ASSESSING THE IMPACT OF AN OPERATING TAILINGS STORAGE FACILITY ON CATCHMENT SURFACE AND GROUNDWATER QUALITY: A CASE STUDY OF ADAMUS RESOURCES LIMITED (NZEMA GOLD MINE) IN THE ELLEMBELE DISTRICT OF THE WESTERN REGION OF GHANA BY ELVIS AKWASI ACHEAMPONG (10443343) THIS THESIS IS SUBMITTED TO THE UNIVERSITY OF GHANA, LEGON IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF MASTER OF PHILOSOPHY DEGREE IN ENVIRONMENTAL SCIENCE COLLEGE OF BASIC AND APPLIED SCIENCES INSTITUTE FOR ENVIRONMENT AND SANITATION STUDIES UNIVERSITY OF GHANA LEGON MARCH, 2016 University of Ghana http://ugspace.ug.edu.gh i DECLARATION I testify that this research work was carried out entirely by me at University of Ghana under the supervision of the under listed supervisors. This thesis has never been presented, either in part or whole, for the award of a degree in this university or any other institution. All cited works and assistance have been fully acknowledged. ………………………….. .…………………………… Acheampong Akwasi Elvis Date (Student) ……………………………….. ……………….……………. Prof. F. K. Nyame Date (Principal Supervisor) ……………………………….. ……………………………… Dr. Daniel Nukpezah Date (Co-Supervisor) University of Ghana http://ugspace.ug.edu.gh ii DEDICATION This thesis is dedicated to my loving wife, Mrs Dorcas Acheampong and son, Obrempong Boakye Acheampong. University of Ghana http://ugspace.ug.edu.gh iii ACKNOWLEDGEMENT Firstly, I give thanks to Almighty God for his divine protection and guidance throughout my life and during this study. My appreciation also goes to my Supervisors - Prof. Frank K. Nyame (Principal Supervisor), of the Department of Earth Sciences and Dr. Daniel Nukpezah (Co- Supervisor), a Research Fellow at the Institute for Environment and Sanitation Studies for their constructive criticisms, guidance and important contributions to the study. I am grateful to Mr. George Owusu Ansah, Environmental Manager of Adamus Resources Limited, Nzema Gold Mine for his tutelage. I am equally gratefully to Mr. Joseph Nanor, Director of Quality Environmental Consult (QEC) for his constructive comments and criticisms. My sincere appreciation goes to these institutions- University of Ghana – Carnegie Foundation (USA) Next Generation of Academics in Africa Project for funding this work and Adamus Resources Limited (Nzema Gold Mine) for their permission to use their site and facilities for the study. University of Ghana http://ugspace.ug.edu.gh iv TABLE OF CONTENTS DECLARATION....................................................................................................................... i DEDICATION......................................................................................................................... ii ACKNOWLEDGEMENT ..................................................................................................... iii TABLE OF CONTENTS........................................................................................................iv LIST OF TABLES ............................................................................................................... viii LIST OF FIGURES.................................................................................................................ix LIST OF ABBREVIATIONS ................................................................................................xi ABSTRACT ......................................................................................................................... xiii CHAPTER ONE....................................................................................................................... 1 INTRODUCTION .................................................................................................................... 1 1.1 Background .................................................................................................................... 1 1.2 Problem Statement and Relevance of Study ................................................................ 3 1.3 Objective of the Study ................................................................................................... 4 CHAPTER TWO ...................................................................................................................... 6 LITERATURE REVIEW ........................................................................................................ 6 2.1 Overview of Water ......................................................................................................... 6 2.2 Water Cycle .................................................................................................................... 6 2.3 Groundwater Recharge and Discharge ......................................................................... 7 2.4 Water Quality ................................................................................................................. 8 2.4.1 Water Quality Parameters ...................................................................................... 9 2.4.1.1 Biological Oxygen Demand (BOD) ................................................................... 9 2.4.1.2 Color ..................................................................................................................... 9 2.4.1.3 pH ....................................................................................................................... 10 2.4.1.4 Conductivity....................................................................................................... 10 2.4.1.6 Cadmium ............................................................................................................ 12 2.4.1.7 Arsenic ............................................................................................................... 12 2.4.1.8 Copper ................................................................................................................ 12 2.5 Tailings Dams............................................................................................................... 13 2.5.1 History of Tailings Dam....................................................................................... 13 2.5.2 Key Features of a Tailings Storage Facility............................................................ 15 2.5.3 Planning, and Design of TSF ............................................................................... 16 2.5.4 Tailings Construction Methods............................................................................ 17 2.6 Types of Tailings Impoundments ............................................................................... 18 2.6.1 Valley Impoundment, Ring Dyke and In-pit ...................................................... 18 University of Ghana http://ugspace.ug.edu.gh v 2.7 Operation of Tailings Storage Facilities ..................................................................... 19 2.7.1 Methods of Tailings Discharge ............................................................................ 19 2.7.1.1 Single Point ........................................................................................................ 20 2.7.1.2 Alternating Single Point .................................................................................... 20 2.7.1.3 Multiple Discharges .......................................................................................... 20 2.7.1.4 Hydro cyclones .................................................................................................. 21 2.8 Tailings Depositional Strategies ................................................................................. 21 2.9 Monitoring of TSFs ..................................................................................................... 22 2.9.1 Visual Inspection and Use of instruments........................................................... 23 2.9.2 Ground and Surface Water Monitoring ............................................................... 25 2.10 Environment Impacts of Tailings Storage facility ................................................... 25 2.10.1 Air Pollution ....................................................................................................... 25 2.10.2 Soil Contamination ............................................................................................. 26 2.10.3 Water Pollution ................................................................................................... 26 2.11 Seepage Control ......................................................................................................... 28 2.12 Liner Applications ..................................................................................................... 29 2.13 Risk and Emergency Action Plans............................................................................ 30 2.14 Closure of TSFs ......................................................................................................... 30 2.15 Water Supply in Rural areas in close proximity to surface nines in Ghana ........... 31 CHAPTER THREE ................................................................................................................ 34 METHODOLOGY ................................................................................................................. 34 3.1 Study Area .................................................................................................................... 34 3.1.1 Site Location ......................................................................................................... 34 3.1.2 Natural and Physical Environment ...................................................................... 36 3.1.2.1 Climate ............................................................................................................... 36 3.1.2.2 Rainfall ............................................................................................................... 36 3.1.2.3 Temperature and Evapo-transpiration .............................................................. 37 3.1.2.4 Local Geology and Soils ................................................................................... 38 3.1.2.5 Hydrogeology and Hydrology .......................................................................... 39 3.2 Design and Construction Background of the Nzema Tailings Storage Facility ...... 41 3.3 Methods ........................................................................................................................ 43 3.3.1 Study Design ......................................................................................................... 43 3.3.1.1 Groundwater Monitoring Borehole Locations and Surface Water Sampling Sites ................................................................................................................................. 44 3.3.1.2 Selection of Water Quality Parameters ............................................................ 47 3.3.1.3 Sampling Frequency .......................................................................................... 47 3.4 Sample Collection and Analysis ................................................................................. 47 3.4.1 In-situ Measurements ........................................................................................... 48 3.4.2 Analysis for Cyanide (CN) .................................................................................. 49 University of Ghana http://ugspace.ug.edu.gh vi 3.4.3 Total suspended solids analysis (TSS) ................................................................ 49 3.4.4 Dissolved Metals .................................................................................................. 50 3.5 Quality Control and Quality Assurance...................................................................... 50 3.6 Questionnaire Administration ..................................................................................... 51 CHAPTER FOUR .................................................................................................................. 52 RESULTS ............................................................................................................................... 52 4.1 Physical Parameters of TSF Decant Water (TSF-DW) ............................................. 52 4.1.1 pH .......................................................................................................................... 52 4.1.2 Electrical Conductivity (EC)................................................................................ 53 4.1.3 Total Dissolved Solids (TDS) .............................................................................. 54 4.1.4 Biological Oxygen Demand (BOD) .................................................................... 55 4.1.5 Colour .................................................................................................................... 55 4.1.6 Total Suspended Solids (TSS) ............................................................................. 56 4.2 Chemical Parameters of TSF Decant Water (TSF-DW) ........................................... 57 4.2.1 Total Cyanide (CN-t)............................................................................................ 57 4.2.2 Free Cyanide (CN-f) ............................................................................................. 58 4.2.3 Weak Acid Dissociable Cyanide (CN-WAD) .................................................... 59 4.2.4 Arsenic .................................................................................................................. 60 4.2.5 Copper ................................................................................................................... 61 4.2.6 Mercury ................................................................................................................. 62 4.2.7 Cadmium (Cd) ...................................................................................................... 63 4.3 Physical Parameters of Groundwater within 500m radius of the TSF ..................... 64 4.3.1 pH .......................................................................................................................... 64 4.3.2 Electrical Conductivity (EC)................................................................................ 65 4.3.3 Total Dissolved Solids (TDS) .............................................................................. 66 4.3.4 Total Suspended Solids (TSS) ............................................................................. 67 4.3.5 Biological Oxygen Demand (BOD) and True Colour........................................ 68 4.4 Chemical Parameters of Groundwater within 500m radius of the TSF ................... 68 4.4.1 Arsenic (As) .......................................................................................................... 68 4.4.2 Copper ................................................................................................................... 69 4.4.3 Cyanide (Total, WAD and Free Cyanide), Cadmium and Mercury.................. 69 4.5 Physical Parameters of Surface Water within 500m radius of the TSF ................... 70 4.5.1 pH .......................................................................................................................... 70 4.5.2 Electrical Conductivity (EC)................................................................................ 71 4.5.3 Total Dissolved Solids (TDS) .............................................................................. 72 4.5.4 True Colour ........................................................................................................... 73 4.5.5 Total Suspended Solids (TSS) ............................................................................. 74 4.5.6 Biological Oxygen Demand (BOD) .................................................................... 75 4.6 Chemical Parameters of Surface Water within 500 m radius of the TSF ................ 75 University of Ghana http://ugspace.ug.edu.gh vii 4.6.1 Arsenic (As) .......................................................................................................... 75 4.6.2 Copper (Cu) .......................................................................................................... 76 4.6.3 Cyanide (Total, Free and WAD Cyanide), Mercury and Cadmium.................. 76 4.7 Pearson’s Product Moment Correlation between Parameters ................................... 76 4.7.1 TSF Decant Water ................................................................................................ 76 4.7.2 Groundwater ......................................................................................................... 77 4.7.3 Surface Water........................................................................................................ 78 4.8 Social Survey................................................................................................................ 78 CHAPTER FIVE .................................................................................................................... 83 DISCUSSION ......................................................................................................................... 83 5.1 Physical Parameters ..................................................................................................... 83 5.2 Chemical Parameters ................................................................................................... 85 5.2.1 Cyanide.................................................................................................................. 85 5.2.2 Arsenic, Cadmium, and Mercury ........................................................................ 86 5.3 Correlation between Parameters ................................................................................. 88 5.4 Social Survey................................................................................................................ 89 CHAPTER SIX ...................................................................................................................... 91 CONCLUSION AND RECOMMENDATION ................................................................... 91 6.1 Conclusion .................................................................................................................... 91 6.2 Recommendation ......................................................................................................... 91 REFERENCES ....................................................................................................................... 93 APPENDICES ......................................................................................................................109 University of Ghana http://ugspace.ug.edu.gh viii LIST OF TABLES Table3.1: Monthly Average, Maximum and Minimum Rainfall Values of Project Area (2000-2006). ................................................................................................................... 36 Table3.2: Average Monthly Temperature of Project area ................................................... 37 Table3.3: TSF Design Parameters ......................................................................................... 43 Table3.4: GPS Coordinates of Sampling Sites ................................................................... 46 University of Ghana http://ugspace.ug.edu.gh ix LIST OF FIGURES Figure 2.1 Diagram of a typical TSF .................................................................................... 16 Figure 4.1 pH of TSF- DW Samples Collected Between June and December, 2014 compared with GHEPA Upper and Lower Limits (2013). ......................................... 52 Figure 4.2 EC of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ......................................................... 53 Figure 4.3 TDS of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ......................................................... 54 Figure 4.4 True Colour of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ................................................ 55 Figure 4.5 TSS of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ......................................................... 56 Figure 4.6 Total Cyanide of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ................................................ 57 Figure 4.7 CN-f of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ......................................................... 58 Figure 4.8 WAD Cyanide of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ................................................ 59 Figure 4.9 Dissolved Arsenic of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ............................. 60 Figure 4.10 Mean Dissolved Copper of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ............................. 61 Figure 4.11 Mean Dissolved Mercury of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ............................. 62 Figure 4.12 Mean dissolved Cadmium of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). ............................. 63 Figure 4.13 Mean pH of Groundwater within 500m radius of the TSF sampled between June-December, 2014 compared with WHO Guideline (2011) and Baseline Mean . 64 Figure 4.14 Mean EC of Groundwater within 500m radius of the TSF sampled between June-December, 2014 Compared with WHO Guideline (2011) and Baseline Mean. ......................................................................................................................................... 65 University of Ghana http://ugspace.ug.edu.gh x Figure 4.15 TDS of Groundwater within 500m radius of the TSF sampled between June- December, 2014 compared with WHO Guideline (2011) and Baseline Mean. ......... 66 Figure 4.16 TSS Levels of Groundwater within 500m radius of TSF sampled between June-December, 2014 compared GHEPA Limit (2013) and Baseline Mean ............ 67 Figure 4.17 Dissolved Arsenic Concentration in Groundwater within 500m radius of the TSF compared with WHO Guideline Limit (2011) and Baseline Mean. ................... 69 Figure 4.18 pH of Surface Water within 500m radius of the TSF compared with WHO (2011) Guideline and Baseline mean. ........................................................................... 70 Figure 4.19 Electrical Conductivity of Surface Water within 500m radius of TSF compared with WHO (2011) Guideline and Baseline Mean ...................................... 71 Figure 4.20 TDS of Surface Water within 500m radius of TSF compared with WHO (2011) Guideline and Baseline mean ............................................................................ 72 Figure 4.21 True Colour of Surface Water within 500m radius of TSF compared with WHO (2011) Guideline and Baseline Mean ................................................................ 73 Figure 4.22 TSS of Surface within 500m radius of TSF compared with GWC Guideline (2013) and Baseline mean ............................................................................................. 74 Figure 4.23 Arsenic Concentration of Surface Water within 500m radius of TSF compared with WHO (2011) Guideline and Baseline mean ....................................... 75 Figure 4.24: Distribution of Respondents in the Study Area. ............................................. 79 Figure 4.25: Age of Respondent in the Study Area. ............................................................ 79 Figure 4.26: Occupation of Respondents in the Study Area ............................................... 80 Figure 4.27: Water Sources Accessed by Respondents in the Study Area. ........................ 81 Figure 4.28: Views of Respondents on the Impact of Tailings Storage Facility on Water Sources............................................................................................................................ 82 University of Ghana http://ugspace.ug.edu.gh xi LIST OF ABBREVIATIONS AMD Acid Mine Drainage ANOVA Analysis of Variance ARD Acid Rock Drainage ARL Adamus Resources Limited CN Cyanide CN-f Cyanide Free CN-t Cyanide Total CN-WAD Weak Acid Dissociable Cyanide DW Decant Water EC Electrical Conductivity GHEPA Ghana Environmental Protection Agency GWC Ghana Water Company HDPE High Density Poly-Ethylene HDTT High Density Thickened Tailings KP Knight Piesold NGM Nzema Gold Mine PVC Polyvinyl chloride University of Ghana http://ugspace.ug.edu.gh xii PWSD Pond beside Water Storage Dam TDS Total Dissolved Solids TMF Tailings Management Facility TSF Tailing Storage Facility TSMB Tailings Storage Facility Monitoring Borehole TSS Total Suspended Solids USEPA United States Environmental Protection Agency WHO World Health Organization WSD Water Storage Dam University of Ghana http://ugspace.ug.edu.gh xiii ABSTRACT The study assessed the impact of an operating Tailings Storage Facility (TSF) of Adamus Resources Limited (Nzema Gold Mine) in the Ellembele District, Western Ghana, on catchment surface and groundwater quality. Water samples were collected between June and December 2014 from seventeen (17) sampling sites including the TSF decant water (TSF-DW), three (3) streams, a water storage dam, a pond and eleven (11) groundwater monitoring boreholes within 500m radius of the mine’s Tailings Storage Facility. Samples were analyzed for pH, true colour, electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), biological oxygen demand (BOD), dissolved metals (arsenic, cadmium, copper, mercury) and cyanide (weak acid dissociable cyanide (WAD), free cyanide and total cyanide) using standard procedures. Structured questionnaires were also administered to one hundred and twenty inhabitants living close to the TSF to solicit their opinion regarding the impact of the facility (TSF) on water quality in the communities out of which one hundred people responded. Results obtained from the analysis of water samples from the TSF-DW indicated that pH values range from 7.4 – 8.9 (mean 8.2), EC 1340 – 1630 µS/cm ( mean 1507.1 µS/cm), TSS 19 – 105 mg/l (mean 55.3 mg/l), arsenic 0.17 - 5 mg/l (mean 1.26 mg/l), cadmium 0.0001- 0.0004 mg/l (mean 0.0002 mg/l), copper 0.058 - 0.35 mg/l (mean 0.15 mg/l), mercury <0.0001 - 0.0002 mg/l ( mean 0.002 mg/l), Weak Acid Dissociable (WAD) cyanide <0.005 - 1.04 mg/l (mean 1.04 mg/l), total cyanide <0.0005 - 1.55 mg/l (mean 0.59 mg/l) and free cyanide <0.005 - 1.04 mg/l (mean 0.38 mg/l). pH values of surface water samples collected ranged from 6.3 -7.3 (mean 6.7), EC 55.5 – 185.7 µS/cm (mean 116.8), TSS 10.7- 990 mg/l (mean 230 mg/l), arsenic 0.001- 0.021 mg/l (mean 0.021 mg/l), copper University of Ghana http://ugspace.ug.edu.gh xiv 0.001 – 0.004 mg/l (mean 0.0020 mg/l). Cyanide (free, WAD and total), cadmium and mercury concentrations in surface water were however, below laboratory detection limit. However, copper in surface water had a strong positive correlation with TDS (r=0.88) and TSS (r=0.84). The pH of groundwater varied between 6 – 7.6 (mean 6.6), EC 114.7- 441 mg/l (mean 233.8 mg/l), TSS 2.9-29.6 mg/l (mean 10.0 mg/l), arsenic 0.0005-0.0063 mg/l (mean 0.0014mg/l) and copper <0.001-0.0026 mg/l (mean 0.0015 mg/l). Cyanide (free, WAD and total), cadmium and mercury concentrations in groundwater were below laboratory detection limit. There was a significant positive correlation between groundwater cadmium and copper (r=0.68). Pearson’s Product Moment Correlation revealed arsenic in TSF-DW had strong positive correlation with copper (r=0.87), total, free and WAD cyanide (r=0.88, 0.85 and 0.93, respectively). The tailings decant water reported elevated arsenic, free cyanide and TSS concentrations above GHEPA guideline for effluent discharge which could be attributed to arsenopyrite ore mined and processed by the mine and chemicals used in ore processing. Free cyanide, arsenic and TSS values in the TFS were above GHEPA guidelines. Elevated TSS and arsenic concentrations above GHEPA limits were reported in PWSD which is a pond uphill of the TSF and a receptor to effluents from illegal mining sites on the mine’s concession. All other parameters recorded in surface and groundwater bodies studied were within WHO guideline limit for potable water. Results of the study suggest that the quality of surface and groundwater around the TSF has not been adversely affected even though the TSF is contaminated. Study findings suggest that well-engineered tailings dam of ARL with its effective liner and management systems and may have provided a safe structure and prevented contamination of water resources within its catchment. Adherence to the University of Ghana http://ugspace.ug.edu.gh xv mining industry’s best practices by ARL with regards to TSF management could also be a contributing factor to the quality of water bodies in close proximity to the facility. However, inhabitants living close to the TSF believe their water quality has been impacted adversely by the facility with five percent (5%) of the respondents relating the impact to smell, 78% to colour and 17% to odour. University of Ghana http://ugspace.ug.edu.gh 1 CHAPTER ONE INTRODUCTION 1.1 Background Mining plays a key role in the socio-economic development of many countries and Ghana is a good example. Hinton e t a l . (2003) outlined positive aspects of mining including creation of employment, contribution to government revenue, foreign currency earnings and increase of Gross Domestic Product (GDP). Mining operations generally produce many types of waste including tailings and waste rocks, many of which are dumped or contained in facilities near extraction or processing sites. Wastes generated from such mining operations are of grave concern to stakeholders (government, community and company) owing to their potential detrimental impacts on water resources and environment in general. Many mining operations also utilize large volumes of water for mineral processing, controlling dust, and meeting the diverse needs of workers on site (Acheampong et al., 2013). Mine tailings, which are solid-liquid slurry materials made up of fine-grained waste particles remaining after ore treatment (e.g., milling, flotation, separation, leaching), are often stored in a Tailings Storage Facility (TSF) and managed to optimize the amount of tailings stored as well as reduce potential adverse environmental impacts. According to Liu et al. (2008), the components of mine tailings depend to a large extent on the chemicals and the method used in the mineral extraction, as well as the geology of the mined ore been processed. Authors such as Roussel et al. (2000) contend that tailings from mineral processing, in particular, serve as a main source of contamination of University of Ghana http://ugspace.ug.edu.gh 2 catchment surface and groundwater resources. The liquid component of tailings is made up of water and chemicals used in processing of ore. Contents of TSFs could therefore be highly contaminated and are hence not discharged directly into the environment in conformity with international best practice for mining industries. It is therefore imperative to properly manage tailings as they constitute a major source of release of many trace elements and other contaminants into the environment (Bempah et al., 2013). In the case of gold bearing ore, about 95 to 97% of ore processed ends up as tailings or process waste that must be discarded (Paull et al., 2006). After mineral concentrate has been separated from ore, the unrecoverable and uneconomic metals, minerals, chemicals, organics and process water are sent via a pipeline as slurry to a secured storage facility or dam at the mine site (Tailings Storage Facility or TSF or Tailings Management Facility or TMF) (Vick, 1990). Tailings usually include metal precipitates resulting from neutralization sludges or residues from pressure leaching processes. Such materials may exhibit long-term chemical stability concerns and need to be disposed in secure, lined facilities. A TSF or TMF is a large area usually located in a natural hollow or valley. Tailings storage facilities are important and indispensable components in the mining and processing of minerals. Depending on methods used in construction, geology of mine sites, climate, nature of ore mined and/or treated, and overall management, tailings storage facilities may exact variable impacts on the immediate surrounding environment. According to Vick (1990), seepage of some process water from Tailings Storage Facilities may be inevitable irrespective of the facility’s engineering design. Azcue et al. (1994) also suggest that problems arise where excess seepage of process waste from the TSF impacts on the environment. University of Ghana http://ugspace.ug.edu.gh 3 The mining industry contributes 40% of Ghana’s gross foreign exchange earnings and directly employs about 18,000 people, most of whom are Ghanaians (Hilson, 2005). The sector also contributes to development through implementation of Corporate Social Responsibility (CSR) programmes for host communities and the general public at large. Because of the important role that mining plays in the economy of Ghana, the government and regulatory agencies such as the Environmental Protection Agency (EPA) and Minerals Commission closely monitor the activities of mining companies to ensure the country maximizes the benefits and minimizes risks or negative impacts including pollution of the environment that may result from mining operations. 1.2 Problem Statement and Relevance of Study Many large-scale mining companies in Ghana, such as Adamus Resources Limited , often operate in areas also inhabited by local communities within the catchment areas of the mine. Communities such as Tarkwa, Nsuta, Teberebie, Teleku-Bokazo and New Abirem are, for example, are located in the proximities of the operations of Gold Fields Ghana Limited, Ghana Manganese Company Limited, AngloGold Ashanti (Iduapriem), Adamus Resources Limited and Newmont Ghana Limited, respectively. Groundwater contamination is of grave concern where the groundwater feeds surface streams or lakes, or where the groundwater is being used as a source of drinking water and water for other chores by people living close to a mine (Smedley et al., 1996). Adamus Resources Limited, a subsidiary of Endeavour Mining of Canada, operates a surface gold mine in the Ellembele District in the Western Region of Ghana. The University of Ghana http://ugspace.ug.edu.gh 4 company has a Tailings Storage Facility (TSF),which receives effluents from processing of sulphide (mainly arsenopyrite-rich) ore. The mine and its TSF is located in an area that is also inhabited by local communities such as Akango, Aluku, Angajale, Teleku- Bokazo and Salman all of whom depend on surface and groundwater resources in the proximity of the mining and ore processing activities. Smedley et al. (1996), Ahmad & Carboo (2000) and Akabzaa et al. (2005) reported high metal concentrations in water, soil, fruits, food crops, biological tissues, rivers, school compounds, farmlands and settlements close to tailings dams or facilities in Obuasi, Prestea and Tarkwa township. However, studies on the impact of TSF on catchment water bodies are unavailable in the Ellembele District of Ghana as Adamus Resources Limited (ARL) is the first large scale mining firm to operate in the area. In addition, communities close to Adamus Resources’ TSF depend largely on surface and groundwater for drinking purposes, subsistence agriculture and other domestic uses. This study therefore assessed the quality of surface and groundwater resources in the proximity of Adamus Resources’ tailings facility to determine whether, after four years of active mining and ore processing, any perceptible impacts may occur in these water resources and, if possible, to suggest mitigating measures to major stakeholders. The study also solicited views of inhabitants on their perceptions of the impact of the company’s tailings storage facility on the quality of water resources in the area. 1.3 Objective of the Study The main objective of the study was to ascertain the impacts of an operating Tailings Storage Facility on catchment surface and groundwater quality. To address this broad University of Ghana http://ugspace.ug.edu.gh 5 objective, the under listed specific objectives guided the study:  Determine concentrations of Ghana Environmental Protection Agency (GHEPA) conventional pollutants for the mining sector in ARL’s TSF decant water, groundwater monitoring boreholes and surface water bodies within 500 m radius of the tailings dam.  Comparison of the concentration obtained with GHEPA, Ghana Water Company (GWC) and World Health Organization (WHO) guidelines as well as the baseline data of the mine to ascertain impacts.  Soliciting the views of inhabitants living close to the TSF on whether or not the quality of their surface and groundwater m a y have been impacted by the facility after four years of active mining operations. University of Ghana http://ugspace.ug.edu.gh 6 CHAPTER TWO LITERATURE REVIEW 2.1 Overview of Water Water is essential to the welfare and existence of man and other living organisms on earth. It represents one of the basic elements supporting life and the natural environment, a major component of industrial processes, a consumer item for humans and other animals, a key requirement of photosynthesis and a major vector for domestic and industrial pollution (Gleick, 1996). According to Downing et al. (2006), water covers three-fourth of the entire surface of the earth. Its unique chemical properties make it an indispensable element in most manufacturing and chemical processes. Water is ubiquitous and therefore found on the ground (surface water), underground (groundwater), in living organisms, soil and even combined with different elements in rocks. 2.2 Water Cycle The water or hydrological cycle, describes the continuous circulation of water between surface water bodies such as the ocean, rivers and streams, the atmosphere and land through evaporation, precipitation, infiltration and runoff (Cook, 2013). It is a complex process powered by solar energy from the sun. In the cycle, precipitation (rain, sleet or snow) falls on the ground and is either intercepted by plants and transpired or becomes overland flow contributing to the surface water network, or seeps into the ground (Lamontagne et al., 2014). When surface water percolates slowly down through soil and rock, it eventually reaches a University of Ghana http://ugspace.ug.edu.gh 7 layer that it cannot pass through, where it slowly accumulates and saturates the ground above this layer. The top of this saturated zone is known as the water table (Knapp, 2002). 2.3 Groundwater Recharge and Discharge Recharge can be explained as the replenishment of water to a groundwater system from the ground surface. It mostly occurs naturally and in some instances induced artificially (Hughes, 2004). Infiltration of rainfall beneath the land surface and its movement to the water table is a widespread form of natural recharge. Aquifers can also be naturally recharged from surface water infiltrating the ground from water bodies such as rivers, creeks, lakes, dams and wetlands (Schmidt et al., 2011). According to Bouwer (2002), it is possible to artificially recharge an aquifer for subsequent recovery or environmental benefit. This is termed as managed aquifer recharge (MAR) or aquifer storage and recovery (ASR). In urban areas, MAR can be used to store desalinated seawater, recycled water, storm water and even mains water, reducing transportation costs and water lost to evaporation. Discharge can be defined as the process by which water leaves an aquifer. For unconfined aquifers, groundwater generally flows from recharge areas on higher ground to low-lying discharge areas. Groundwater can discharge from an aquifer in a number of ways. Where the flow from an aquifer is slow and spread over a large area, it discharges by seepage; where it is localized and rapid, it discharges through a spring (Cook, 2013). Groundwater can discharge directly into streams, rivers, lakes and wetlands where they intersect the groundwater table. University of Ghana http://ugspace.ug.edu.gh 8 A river may receive water from an aquifer through its bed - a process that may not be visible. Discharges to rivers account for most of the flow from aquifers. In drought, groundwater maintains surface water supplies for human use. Groundwater is convolutedly connected with surface water through recharge and discharge and commonly affects the volume and quality of rivers, lakes and wetlands (Polubarinova- Koch, 2015). Excess water flows to surface water bodies when aquifers exceed their storage capacity. 2.4 Water Quality According to Downing et al. (2006), water quality determines the appropriateness of water for particular purposes such as dinking, cleaning, irrigation and industrial processes. It is defined in terms of the chemical, physical and biological aspects of water. The quality of water is dynamic and a function of state, time, and location. Industrialization, agriculture and other economic activities have put excessive strain on the quality of water, which is already a scarce resource in Ghana and other parts of the world. Decline in water quality has become a global issue of concern as human population continues to surge, industrial and agricultural activities expand, and climate change threatens to cause major alterations to the hydrological cycle. In the absence of human impacts, water quality would be determined by weathering of bedrock minerals, by atmospheric processes of evapo-transpiration and deposition of dust and salt by wind, by the natural leaching of organic matter and nutrient from the soil, by hydrological factors that lead to runoff, and by biological processes within aquatic environment that can modify the physical and chemical composition of water (Lumb et al., 2006). University of Ghana http://ugspace.ug.edu.gh 9 2.4.1 Water Quality Parameters 2.4.1.1 Biological Oxygen Demand (BOD) BOD is the amount of oxygen consumed by bacteria in the breakdown of organic material. While a dissolved oxygen test tells you how much oxygen is available, a BOD test tells you how much oxygen is being consumed. BOD is determined in the laboratory by measuring the dissolved oxygen level in a freshly collected sample and comparing it to the dissolved oxygen level in a sample that was collected at the same time but incubated under specific conditions for about five (5) days. The difference in the oxygen readings between the two samples in the BOD is recorded in units of mg/L (Koenings et al., 1991). Unpolluted, natural waters should have a BOD of 5 mg/L or less. Raw sewage may have BOD levels ranging from 150 – 300 mg/L (Moyle, 1996). It can also be determined by water quality multi parameter probe by immersing the probe in the water and taking BOD readings when the readings stabilize. Chemical Oxygen Demand (COD) on the other hand is the amount of oxygen that will be consumed directly by an oxidizing chemical contaminant. 2.4.1.2 Color Color is considered as a pollution problem in terms of aesthetics, but is not generally considered a threat to aquatic life. Increased color may interfere with the passage of light, thereby impeding photosynthesis in an aquatic environment (Koenings et al., 1991). It is a measure of the dissolved coloring compounds in a water body. The color of water is mainly as a result of the presence of organic and inorganic materials. University of Ghana http://ugspace.ug.edu.gh 10 Color is expressed as Pt-Co units according to the platinum-cobalt scale (Simeonov et al., 2003). Water color can naturally range from 0-300 Pt-Co. Higher values are mostly associated with swamps and bogs. 2.4.1.3 pH The pH of water can be defined as measurement of how acidic or basic (alkaline) water body is. It is represented as the negative common logarithm of hydrogen ions concentration. The pH of water bodies can provide relevant information about many chemical and biological processes and provides indirect correlations to a number of different impairments (Yamamoto et al., 2005). According to Salomons (1995), water bodies around tailings impoundments with significantly low values of pH may indicate a likely process of acid mine drainage taking place. On the other hand, high pH values (up to 10) may sometimes infer the presence of cyanide. 2.4.1.4 Conductivity Conductivity is the numerical expression of the water's ability to conduct an electric current (Simeonov et al., 2003). It is measured in micro Siemens per cm and depends on the total concentration, mobility, valence and the temperature of the solution of ions (Boyd, 2015). Electrolytes in a solution disassociate into positive (cations) and negative (anions) ions and impart conductivity. Most dissolved inorganic substances are in the ionized form in water and contribute to conductance accordingly. Among these substances are chloride, sulfate, sodium, calcium and others. After the gold has been extracted from its component ore, some previously bonded inorganic components become “free” and therefore may contribute to the amount of total ions in solution. In other instances, they may react with other mobile ions to form salts (Liu et al., 2008). University of Ghana http://ugspace.ug.edu.gh 11 The conductance of the samples gives rapid and practical estimate of the variation in dissolved mineral content of the water supply. 2.4.1.5 Cyanide Cyanide in water bodies mostly come from industrial activities predominantly processing of gold ore by mining industries. Cyanide is a likely substance to leak from gold tailings storage facility (Hilson & Monhemius, 2006). Cleaning waters of blast furnaces, synthesis processes in the chemical and petrochemical industries are also potential sources. Cyanide is a lethal substance and kills within few minutes of exposure by rendering tissues or animals including humans incapable of oxygen exchange (Eisler & Wiemeyer, 2004). At pH less than 8, cyanide exists as un-dissociated hydrogen cyanide (HCN), which is more toxic to aquatic life than the free cyanide ion. Cyanide is acutely toxic to most species of fish at concentrations greater than 200 µg/L. Cyanide, though toxic, is easily broken down when exposed to sunlight. Cyanide breaks down quickly in surface water to form other products and the three (3) most commonly monitored species in surface waters around mining companies are: free cyanide, weak acid dissociable cyanide (WAD), and total cyanide. Cyanide is measured in various forms in water samples. It can be reported in either µg/L or mg/L. Cyanide has the potential to combine with metals to form a variety of compounds. The form it takes is largely contingent on salinity, temperature, pH, dissolved oxygen, and the presence of other ions such as chloride. When cyanide is run through a heap, it leaches not only gold, but also leaches arsenic, mercury, selenium, and certain other heavy metals (Donato et al., 2007). University of Ghana http://ugspace.ug.edu.gh 12 2.4.1.6 Cadmium Cadmium is closely linked with zinc and lead in the natural environment. Cadmium pollution of water bodies mostly comes from mining effluents. Cadmium has cumulative and highly toxic effects in all chemical forms and accumulates in plant cells (Friberg et al., 1974). It is also known to have extremely toxic effects on trout and zooplankton (Cherif et al., 2015). Cadmium is measured in either the total or dissolved state in a water sample. It is reported in mg/L or µg/L and is generally found in trace concentrations of less than 0.1 µg/L. At high pH cadmium precipitates from solution. 2.4.1.7 Arsenic Arsenic in drinking water is a hazard to human and aquatic health. It is largely and naturally present in the biosphere, principally in the form of As2S2 or As2S3. This element is used in metallurgy as alloys, in electronics as semiconductors, the tanning industry as sulphides, paint formulations and glass colouration (Petrusevski et al., 2007). According to Smith et a l. (2000) the main source of arsenic in drinking water is arsenic-rich rock through which the water has filtered. Arsenic poisoning from groundwater especially can have numerous health effects, ranging from circulatory disorders gastrointestinal upsets, diabetes, peripheral neuropathies, and skin lesions (Kapaj et al., 2006). The maximum permissible limit for arsenic in water applied by WHO is 10 μg/L. 2.4.1.8 Copper Copper is essential nutrient for all plants and animals. Elevated quantities give drinking water a bad taste (McConnell & Rosado, 2000). Extremely large and University of Ghana http://ugspace.ug.edu.gh 13 prolonged doses may result in liver damage. According to Guilizzoni (1991), copper is acutely toxic to most forms of aquatic life at relatively low concentrations. Copper is measured in either the total or dissolved state in a water sample. It is reported in either µg/L or mg/L and is generally found in trace concentrations in the range from 1-10 µg/L. presence of copper in water bodies mostly comes from mining and other industrial effluents. 2.5 Tailings Dams 2.5.1 History of Tailings Dam Crushing of ore to expose metals of interest was done in the early years of mining but involved relatively small volumes and unsophisticated technology. Technological advancement c ou p l ed with the advent of high steam engines has led to increase in the capacity of grinding mills resulting in a surge in the volumes of tailings generated after the ore treatment process (Rico et al., 2008). In the early days of mining, after minerals of economic interest had been separated usually by specific gravity, remnant tailings were routed to a location that was deemed convenient. Streams and other water bodies in close proximity to the mine were the main receptors of mine tailings owing to weak or nonexistence of environmental laws that prohibited such act. In addition, people were barely aware of the environmental implications of that mode of mine tails disposal. Invention of flotation and cyanidation technology in the late 1800s increased the extraction of economic metals from low grade ores and resulted in the production of huge volumes of tails with finer gradation (Azam & Li, 2010). This new development University of Ghana http://ugspace.ug.edu.gh 14 resulted in increased pollution of water resources in mining areas in several parts of the world. Conflict arose between mining companies and people who depended on water bodies for agriculture and other economic endeavors. Farmers close to mining areas began to experience lesser yields and crop began to show signs of strange diseases due to contamination of water and land by mine tailings (Davies, 2002). This unfortunate development led to a surge in tailings pollution related litigation in most mining countries especially in Europe and North America where people were becoming better informed about environmental and health implication of improper tailings disposal. By 1930, indiscriminate disposal of mine tailings was illegal in most part of the world owing to restrictive laws that were enacted following the numerous law suits. To stay in business and be in good relationship with indigenes and other stakeholders, mining firms recognized the need to construct dams to safely contain tailings. Dams in the early days were usually built across stream channel with limited provisions for infrequent floods and most of these dams failed to stand the test of time after heavy rainy events. There was initially very little or no engineering or regulatory inputs involved in the construction and operation of tailings dams (Vick, 1990). A hand labor construction method was employed in construction of dams, as mechanized earth moving equipment was not available. Low dyke impoundments were initially filled with hydraulically deposited tailings and then incrementally raised by constructing low berms above and behind the dyke of previous level. A similar but University of Ghana http://ugspace.ug.edu.gh 15 more mechanized procedure is used in modern construction of tailings dam. The arrival of high performance earth moving equipment’s in the 1940s in open pit mines provided opportunity for construction of tailings dams of compacted earth fill in a manner similar to conventional water dam practice with its attendant higher degree of safety (Rico et al., 2008). Davies (2000) explains that, tailings dam structural issues such as seepage phenomena, static and earthquake induced liquefaction of tailings and foundation stability were better understood and informed the design of tailings impoundment facilities. On the other hand, issues related to geotechnical stability were not given the needed attention. Post mining land reclamation concerns were also not captured in tailings design. In recent times, mining and its environmental issues have grown immensely in relevance. The focus now is not only on mine economics and physical stability of TSF’s but also, the potential pollution of environmental resources by contaminants from mine tailings dam. 2.5.2 Key Features of a Tailings Storage Facility A typical tailings dam comprises a pond which mostly contains the tailings, the embankments, spill way and a series of underground and under pipes (Vick, 1990). The figure below provides details of key features showing free board and flood capacity. University of Ghana http://ugspace.ug.edu.gh 16 Figure 2.1 Diagram of a typical TSF Source: Vick (1990) 2.5.3 Planning, and Design of TSF Tailings Storage Facilities are planned in line with the general mine plan for the project and this plan is reviewed intermittently when it becomes necessary. Site selection and characterization is usually the first and most important step in the entire tailings impoundment design process. Site selection is dependent on availability of site, construction method, location of domestic water supply, cost of operation and closure of the facility, geotechnical and geological conditions of area, storage capacity required of the TSF, the hydrology of the area, and the ease of the day to day operations. Obermeyer & Alexieva (2011) described the site selection process and outline the process as follows:  Regional screening to eliminate unsuitable areas and locate potential sites University of Ghana http://ugspace.ug.edu.gh 17  Eliminate site with obvious environmental constraints  Qualitative ranking of sites evaluation criteria  Quantitative ranking of sites  Field investigating of top ranking sites  Evaluation of field data  Selection of preferred sites. 2.5.4 Tailings Construction Methods The three main methods of tailings impoundment construction are the upstream, downstream, and centerline (Davies, 2002). Upstream method is the oldest among the three methods. According to T ilt et a l. (2009), tailings dams that are constructed using the upstream method are less stable than those constructed by either the downstream or the centerline method from a seismic point of view. In Idaho in the United States for example, upstream construction method is discouraged and considered unsuitable especially for high impoundments, which are constructed to contain large volumes of solids or water or both. TSFs constructed by upstream technique are most susceptible to post earthquake deformations and liquefaction (Rosenberg et al., 2000). Ghanaian mining regulations do not encourage the upstream method of tailings construction especially where the risk involve ranges from moderate to high. The downstream method is the most expensive method and also the more stable than the other two (Obermeyer & Alexieva, 2011). It is better able to respond to liquefaction and can be used in areas of high seismicity. Downstream TSFs are suitable for storing any type of tailings and can hold significant volumes of water. University of Ghana http://ugspace.ug.edu.gh 18 Centerline construction is a hybrid of upstream and downstream construction types and has risks and costs lying between them (Davies, 2002). The centerline method has acceptable resistance compared to the upstream method. It is however, not recommended for permanent storage of water. The upstream method for tailings dam construction is more liable to failure as compared to those built by the downstream method which is mostly attributed to embankment material generally having a low relative density and high water saturation (Davies, 2002). The upstream method involves construction of walls on top of consolidated and dehydrated tailings in an upstream direction usually using waste rock or tailings as material for construction; the downstream method involves construction with waste rock or borrow materials in a downstream direction; and the centerline method involves construction of the walls above a fixed crest alignment, using waste rock, borrow materials, or tailings (Rico et al., 2008). 2.6 Types of Tailings Impoundments Tailings impoundments geometry is generally dictated by the topographic condition of the site. There are three main impoundments categories and include:  Valley impoundments  Ring dyke (Paddocks or cells)  In-pit 2.6.1 Valley Impoundment, Ring Dyke and In-pit A valley impoundment is normally utilized to take advantage of the natural topography of the land. Valley impoundment is subdivided into cross valley, side hill University of Ghana http://ugspace.ug.edu.gh 19 and valley bottom. As pointed out by Blowes et al. (1998), c ro s s valley impoundment design is similar to the layout of a conventional water storage reservoir in that an embankment is placed across the valley to dam a drainage area. Diversion ditches, spillway or upstream water dams may be essential to divert peak flood flows. Ring Dyke impoundment is also known as Paddock or cell and is not dependent on topographical depressions as in the case of valley impoundments. Ring dyke is more flexible for site selection purposes and can usually be located relatively close to the processing plant (Dwyer, 2000). The ultimate advantage of the Ring dyke is that surface runoff cannot inundate the tailings storage area making the contained water within the TSF being entirely process or precipitation derived. As the name suggests, In-pit involves simply backfilling abandoned open pit of surface mines with tailings. In-pit impoundment is usually preferred by mine operators as worked out voids can be filled at a fraction of the cost associated with designing, constructing and operating a conventional thickened paste or dry stack facility. As espoused by Bl ight (2009), the In-pit impoundment has an additional advantage of not requiring retaining walls, thus risk associated with embankment instability are eliminated. 2.7 Operation of Tailings Storage Facilities 2.7.1 Methods of Tailings Discharge Decisions about how to discharge tailings must be made at the design stage of the life of a TSF and operator must be made aware of and implement the adopted procedure (Rosenberg et al., 2000). The design and operating practices for tailings transport, University of Ghana http://ugspace.ug.edu.gh 20 placement and decant recovery are closely inter-related. Additionally, the method and direction of tailings discharge, depositional strategy, and the location of decant pond are also interconnected. For storage of tailings in impoundments, it is pertinent to ensure a distribution of tailings, which will effectively utilize the storage volume available. Typical discharge methods to achieve as per international best practices are as follows: 2.7.1.1 Single Point For some depositional strategies and surface topography, a single point discharge is a possibility. However, if the discharge point is kept in one location, tailings may build up from this point and the filling of the impoundment may be uneven, requiring a more sophisticated method (Vick, 1990). 2.7.1.2 Alternating Single Point This method involves discharging a full stream of tailings from a single point at any one time, but with other points available. With this method, discharge points are often alternated from time to time. This method may be utilized where there are separated valleys to the storage and areas where even filling is required (Redwan & Rammlmair , 2012). 2.7.1.3 Multiple Discharges This method is popularly known as spigotting and is an alternative to single point discharge. This involves installing a header main a long the full crest length of the embankment with multiple valve outlets at say 10 m or 20 m centers (Wei et al., 2016). The discharge can then be rotated around the storage by using limited or small outlets University of Ghana http://ugspace.ug.edu.gh 21 for a time, then closing them and opening the next series of small outlets. 2.7.1.4 Hydro cyclones This technique is used where tailings contain significant proportion of sand. Hydro cyclones may be used to separate the coarser, more freely draining material from the finer fraction (Bascetin et al., 2016). It is however, difficult to use for fine graded tailings. Additionally, separation is not likely to be fully efficient in slurries containing significant proportion of clay fines (as from oxide ores). Mostly, hydro cyclones are located on the embankment walls. This technique is very expensive and is rarely used by mining companies. 2.8 Tailings Depositional Strategies According to Redwan & Rammlmair (2012), there are three main strategies of depositing tailings in impoundments. The techniques include Sub – Aqueous, Sub – Aerial and Multiple Storage. The Sub-Aqueous method is applicable to tailings where free water is allowed to continuously submerge the tailings surface. This method of deposition may be adopted deliberately for environmental or health and safety reasons (Blowes et al., 1998). This is usually informed by the chemical and/ physical properties of the tailings being deposited. This technique may for example, aim at preventing oxidation of sulphides or emission of radon from radioactive tailings. In some instance, management of site water may not be possible without accepting free water ponded or flowing over tailings. An important feature of this technique is that separation of the tailings solids from the liquid phase occurs by the process of sedimentation and consolidation only. University of Ghana http://ugspace.ug.edu.gh 22 Sub-aerial technique involves the placement of tailings to for an exposed beech for most of the storage area. This results in minimal pond area and thereby reduces total evaporation losses and mostly less attractive to birds (Newman et al., 2001). Multiple storage deposition involves operating more than one storage area and rotating discharge between areas. This facilitates drying of central pond in one area whilst that storage is being rested. It also eliminates the accumulation of wet low strength slurries in the center of the storage area. The flow of seepage through the base is also reduced due to the regular interruption. Scheduling of embankment raising is also made easier since it is not necessary to be discharging into and raising same storage simultaneously. 2.9 Monitoring of TSFs Instrumentation and monitoring program for a tailings dam is usually included in a comprehensive Operations Manual, a document required by legislation in an increasing number of jurisdictions. An effective TSF monitoring system demands geotechnical understanding of the tailings being stored, the design of the facility, seepage migration potential, groundwater flow conditions, potential interaction of the leachate with the soils, and the most probable and significant pathways of potential migration of leachates. It is therefore mandatory in most jurisdictions to have Environmental coordinator or officer and a geotechnical engineer who will superintend the operations and monitoring of the tailings impoundment facility. Hudson-Edwards et al. (2003) highlighted the reasons for instrumentation and monitoring of tailings dam and are rephrased as follows:  To ascertain whether the environmental performance of the facility is meeting design intent, with no downstream out-of-compliance impacts on University of Ghana http://ugspace.ug.edu.gh 23 surface and groundwater quality.  To validate that the dam and its contents are safe from physical point of view right from the construction stage through operations and closure.  To make available the data required for configuration and/or optimization of design and construction through successive stages of TSF construction and development. According to Krausman and Mushtag (2008), the environmental monitoring program of TSFs is usually integrated into the Environmental Management Plan of the mine site. Key environmental aspects that require routine monitoring include:  Impacts on catchment surface and groundwater quality  Impact on groundwater quantity or level and  Generation of odor, noise or dust from the facility  Impacts on fauna especially birds that are susceptible to poisoning after drinking contaminated supernatant water.  Impacts on vegetation. 2.9.1 Visual Inspection and Use of instruments This includes visual inspection of the tailings embankment, monitoring of piezometers and other instrumentations. Distress signals such as wet spots on downstream face, cracking in embankment walls and critical settlement indicate deficiency in the structure (Kossoff et al., 2014). It would however b e difficult to understand the extent of the problem without proper instrumentation. Instruments can be installed to measure pore water pressures, seepage flows, University of Ghana http://ugspace.ug.edu.gh 24 embankment movements, and total pressures (Vick, 1990). Piezometers can be used to measure the pore water pressure in soils. The Casagrande piezometer for example, is a simple and effective piezometer, has a porous ceramic stone element and is designed to measure pressure changes with a minimum lag time. It is installed in a hole drilled into the embankment or its foundation, and probe lowered down the hole measures water levels. Similar types can be installed using porous plastic, porous bronze, perforated steel casing, or steel casing and well points. Hydraulic and electrical piezometers are also available and can be installed at various levels in an embankment but difficult to maintain. Piezometers and inclinators are used to show developing trends in the behavior of deposited materials. The most common design parameters requiring on- going monitoring as pointed out by Mchaina (2001) are:  The phreatic surface in the down-slope retaining embankment and  Excess pore pressure below an upstream embankment Simple methods for measuring embankment movement can be installing markers on the surface aligned in a straight line-of-sight to allow early detection of horizontal movement during periodic surveys. Successive measurement between pegs spaced either side of a crack will indicate any widening and acceleration in separation rate. A more advanced device such as slope indicator can be used to measure horizontal movement. When tailings become consolidated after closure, additional advanced warning stations can be sited within the tailings impoundment by installing piezometers in the tailings to monitor the quality of the groundwater and pore water (Schmitz, 1995). University of Ghana http://ugspace.ug.edu.gh 25 2.9.2 Ground and Surface Water Monitoring Groundwater is one of the most monitored environmental aspects among those mentioned above. A number of groundwater monitoring bores are installed at specially selected locations around the TSF to facilitate monitoring of both groundwater quality and quantity. Selection of bore locations usually requires a good understanding of local groundwater environment and chemistry to ensure the locations and depth of the bores serve their purpose (Krausmann & Mushtaq, 2008). In some situations, several bores are required to intercept several aquifers to ascertain the actual impacts of the TSF on catchment groundwater resource. Shallow bores are usually installed near dam wall to facilitate detection of any seepage that might occur. Surface water bodies that are located close to a TSF are also monitored to detect impacts if any (Heikkinen et al., 2002). 2.10 Environment Impacts of Tailings Storage facility 2.10.1 Air Pollution Emissions from dry tailings to air can be dust, odour, and noise. Usually, dust is the main cause for concern among the three. Dust from tail ings da ms in drier region of the wor ld are exposed to wind erosion and pose a major environmental problem (Rösner & Van Shalkwyk, 2000). This is especially due to the fact that growing vegetation, wind barriers or soil roughness cannot protect these facilities. Tailings impoundments are susceptible to wind erosion particularly when it is dry and the weather is windy. This may transport large volumes of particulate matter, which may contain heavy metals and other contaminants that have potential adverse impact on air quality of downstream areas (Laghlimi et al., 2015). Such dust dispersion can be University of Ghana http://ugspace.ug.edu.gh 26 a nuisance and a health hazard to inhabitants and animals that live in close proximity to the facility. 2.10.2 Soil Contamination Tailings impoundments have the potential to contaminate soils within its immediate environment. This occurs mainly as a result of surface spillages of process wastes; pipeline or tailings dam seepages and by wind-blown dusts emanating from tailings dams (Razo et al., 2004). Potential soil contaminants include heavy metals and remnants of reagents and other chemicals used in the ore treatment process. Contamination of soil by TSF can pose serious threat to human health when directly or indirectly ingested (Krausmann & Mushtaq, 2008). Nutrients content of soils can badly be affected which will eventually lead to annual food yields in mining communities close by. Soil pH may also be affected which can cause stunted growth or death of some plant species. 2.10.3 Water Pollution Tailings Storage Facilities have the potential to impact negatively on both surface and groundwater, either through surface water run off to watercourses or leaching to groundwater (Razo et al., 2004). The type and import of such impacts is dependent on the characteristics of the tails and the environmental setting. The principal water quality issue associated with tailings dams from mines and mineral processing worldwide is considered to be the generation of acid rock drainage (ARD), also known as Acid Mine Drainage (AMD) (Vadapalli et al., 2015). Acid rock drainage (ARD) refers to drainage from the natural oxidation of sulphide minerals contained in rock that is exposed to air and water, resulting in the production of sulphuric acid University of Ghana http://ugspace.ug.edu.gh 27 (Akcil & Koldas, 2006). The root causes of acid mine drainage and its attendant environmental problems are outlined below;  Tailings and/or waste-rock often contain metal sulphides  Sulphides oxidise when exposed to oxygen and water  Sulphide oxidation creates an acidic metal-laden leachate; and  Leachate generation over long periods of time. Sulphide minerals extracted from the bedrock has been formed under strongly reducing conditions resulting in sulphur being present in its lowest oxidation states. The most commonly occurring sulphides are iron sulphides (pyrite FeS2(s) and pyrrotite FeS(s)). These iron sulphides often coexist with other sulphides of higher economic value such as chalcopyrite (FeCuS2(s)); galena (PbS (s)); sphalerite (ZnS(s)) or with sulphides of very little economic value such as arsenopyrite (FeAsS2(s)). However, when the sulphiides become exposed to an oxidizing and humid atmosphere, by the mining activity such as excavation to expose economic ore, they start to oxidize. Geller & Salomons (2012) described the formation of ARD as a three phase process:  Phase I - Involves the relatively slow chemical or biological oxidation of pyrite and other sulphide materials near neutral pH, producing ferrous iron and acidity. This step may be catalysed by the bacteria. Thiobacillus ferroxidans through direct contact with sulphide materials;  Phase II - In the presence of oxygen, ferrous iron is oxidised into ferric iron, which precipitates as ferric hydroxide and releases more acidity. As the University of Ghana http://ugspace.ug.edu.gh 28 pH falls even further, below about pH 3.5 ferric iron remains in solution and oxidizses the pyrite directly; and  Phase III - Acidophillic bacteria rapidly catalyse the process by oxidising ferrous iron into ferric iron and the overall rate of acidity production is increased by several orders of magnitude. This process is commonly demonstrated by pyrite (FeS2(s)) oxidation by oxygen and water with this general chemical equation: 4FeS2 + 14O2 + 4H2O = 4FeSO4 + 4H2SO4 The oxidation reactions yield water with low pH with the propensity to leach and mobilize heavy metals that may be contained in surrounding materials. Acidic water generated mostly contains sulphate and other metals which are deleterious to birds and aquatic life (Grande et al., 2015). The brownish- yellowish coloration often called ’Yellow boy ’ associated with ARD also causes negative visual impacts. 2.11 Seepage Control Seepage control methods must be integrated into the design of the Tailings Storage Facility from the onset to ensure the dam remains continually stable and also to facilitate compliance to applicable environmental regulations (Krausmann & Mushtaq, 2008). The three main aims of seepage control in tailings dam management are to maintain embankment stability, lessen water losses from the facility especially in arid regions and to maintain water quality at the site and areas in close proximity to the facility (Beckett et al., 2015). The above mentioned objectives can be achieved by either; keeping tailings and its constituents in the impoundments or capturing it after it exits the dam. University of Ghana http://ugspace.ug.edu.gh 29 Barrier or collection systems are usually employed to avert seepage from a TSF. Barrier systems maintain or repel the flow of seepage outside the impoundment area whereas collection systems intercept and safely focus the seepage as it leaves the tailings storage facility. Barrier control methods consist of liners and embankment barriers to prevent seepage passing through the tailings containment area into the open environment. Collection methods create pathways for the seepage to accumulate then flow to controlled locations such as embankment toe drains (Razo et al., 2004). Seepage monitoring is essential to evaluate TSF‟s performance. Visual inspections of a tailings facility can determine the superficial operations (e.g. pond control, discharge management, pipework integrity). However, the internal performance of a TSF can only be identified by monitoring variations and irregularities of the seepage effluents (Robertson et al., 2015). Reducing the water content of tailings being delivered into the impoundment facility can decrease seepage remarkably as the water handling and storage volumes of the TSF are reduced. Rösner and Van Schalkwyk (2000) emphasized that this reduces seepage losses and groundwater contamination as there is less moisture present in the deposited tailings and generally supernatant water is nonexistent. 2.12 Liner Applications Liners can be installed beneath the entire impoundment to contain water and to exclude groundwater. Liners can include a high-density polyethylene (HDPE) or other types of geosynthetic material, a clay cover over an area of high hydraulic conductivity, or both. Denis e t a l . (2012) established that a non-exposed HDPE liner could have a predicted lifetime of 69 years at 40 °C to 446 years at 20 °C. Where geomembranes University of Ghana http://ugspace.ug.edu.gh 30 are used, a drainage layer above the membrane is usually included to reduce the water pressure on the liner and thereby minimizing leakage. Liners may cover the entire impoundment area, or only the pervious bedrock or porous soils (Waterhouse & Friday 2000). Full liners beneath TSFs are very expensive an often not opted for by many mining companies; nevertheless, there is a rising demand by regulators for the industry to use liners to minimize risks of groundwater contamination. New mines in Australia for example are required to justify why one wouldn’t be required (Rico et al., 2008). Under-drains reduce water saturation of the tailings sediments in order to improve geotechnical strength and safety of the facility. It also directs drainage toward a storage area for subsequent treatment. Spillway diversion drains are usually constructed to provide a catchment for runoff during extreme rainy events. 2.13 Risk and Emergency Action Plans Risk and emergency action plan should be developed prior to the operation of TSF as required by Ghana’s Environmental Protection Agency. These plans are hinged on the existing tailings management plan, operating manual, monitoring and emergency response plan. 2.14 Closure of TSFs A TSF after closure is required to have either a continuous water cover or an engineered cover to prevent oxidation of tailings, which may generate Acid Mine Drainage (AMD). It is expensive to finance inspections, maintenance, and repairs in post-closure for as long as the tailings exist (Lacy & Barnes, 2006). Closure of a TSF mostly includes containment/encapsulation, minimization of seepage, stabilization with a surface cover to prevent erosion and infiltration, diversions and collection of University of Ghana http://ugspace.ug.edu.gh 31 precipitation, and design of final landform to minimize post-closure maintenance as much as possible. There are a numerous of cover types and depths that can be chosen; the choice is site specific and depends on climate, type and volume of tailings, and geometry of the TSF, available cover material, and the end-use for the property (Lottermoser & Ashley, 2008). Traditionally, water in TSF ponds is drained as completely as possible prior to closure to reduce potential for overtopping and erosion of the embankments; raising water levels in large dams could cause considerable long-term risk. However, water covers might be used when feasible to maintain a submerged condition, such as in regions where the hydrology is well understood and the terrain is flat, such as has been used and encouraged in Canada (Davis & Masten, 2004). Regardless of the type of reclamation used for closure, the reclaimed facility must be monitored and maintained to ensure stability over time. The reclaimed facilities are monitored for any deformations, structural changes, or weaknesses and the surfaces should be inspected for intrusion by animals, humans, or vegetation, any of which could compromise long-term stability. 2.15 Water Supply in Rural areas in close proximity to surface nines in Ghana Although in Ghana laws and regulations have been enacted to monitor and ensure compliance for sound environmental management by mining companies, inhabitants of most communities in close proximity to surface mines are not satisfied with the level of enforcement and compliance (Asante et al., 2007). University of Ghana http://ugspace.ug.edu.gh 32 Many of these communities are of the view that surface mines have negatively affected their environment especially the quality of air, water and forestland (Garvin et al., 2009). This situation has in the past resulted in several confrontations between the communities and the mining companies leading to bloodshed, destruction of property and loss of thousands of dollars (Aryee et al., 2003). With regards to mining effects on rural and urban water supply, Asante et al. (2007) reported that mining has a negative impact on water quality and invariably adversely affect water supply in both urban and rural Ghana. This observation is significant, considering the fact that most rural settlements in Ghana including those close to mining operations have traditionally relied on raw surface waters from sources such as streams, rivers, lakes and ponds and groundwater from dug-out wells and boreholes Water from these sources is more likely to be contaminated and rendered unsafe to drink, hence exacerbating the already existing water scarcity problems confronting rural Ghana (Serfor-Armah et al., 2006). According to a study by Singh et al. (2007), mining operations of Golden Star Resources (Bogoso/Prestea) caused siltation of six (6) rivers in Dumase (Aprepre, Wurawura, Akyesua, Pram, Nana Nyabaa, Nsu Abena) and two (2) rivers in Twigyaa. The operations of AngloGold Ashanti Obuasi mine also caused arsenic contamination of about 12 rivers in Sanso and many communities in Obuasi who do not have access to clean water such as Odumase, Fenaso (Amonoo-Neizer et al., 1996). Cyanide spillages from the TSF of AngloGold Ashanti Iduapriem Limited contaminated rivers such as Achofoe, Angonaben and Bromenasu in Tarkwa. Rivers such as Awura, Atibri, Betihini were also completely buried with mine waste rock by AngloGold Ashanti Iduapriem Limited (Amegbey & Adimado, 2003). University of Ghana http://ugspace.ug.edu.gh 33 The availability of water in wells and boreholes in mining areas has significantly reduced due to pit dewatering and abstraction of water for ore processing. The challenges discussed above have denied many people in these areas access to water for drinking and other household chores (Amonoo-Neizer et al., 1996). The above review suggests a negative socio-economic impact of mining activities on communities close to mining areas. This present study therefore also assesses communities’ views on the extent to which mining has impacted their water resources (surface and groundwater) and general livelihoods University of Ghana http://ugspace.ug.edu.gh 34 CHAPTER THREE METHODOLOGY 3.1 Study Area 3.1.1 Site Location The Nzema Gold Mine is located in the Ellembele district of the Western Region of Ghana and is approximately 280 km west of the capital, Accra, and less than 20 km from the coast at Essiama. The mine is accessed from Accra via the main coast highway to Takoradi and from there by sealed road (of about 77.6 km) to the village of Teleku- Bokazo and then by 10 km of untarred road. The current project setting consists of the following concessions; Salman, Akanko and Ebi-Teleku- Bokazo, which covers a total area of 92.3 sq. km (9,230 ha). The mine footprint is estimated to disturb an area totaling approximately 0.4 % of the total land take. The project falls within the Nzema East and Jomoro Traditional Areas and is situated in the Wet Evergreen Forest Zone with an average annual rainfall of about 2000 mm (Knight Piesold, 2007). The project lays within three major drainage systems namely the Ankobra River to the east, the Amansuri lagoon to the west and the Biare catchment that flows to the south into the Atlantic Ocean. The site is largely transformed as a result of extensive human induced degradation. The main land uses include subsistence and cash crop farming, logging and illegal artisanal mining. There are six distinct communities within the Project area, namely Teleku-Bokazo, Anwia, New Aluku, Salman, Akanko and Duale (Ichino & Nathan, 2013). Additionally, a number of smaller satellite communities also exist within the University of Ghana http://ugspace.ug.edu.gh 35 project catchment area. The location of the study area is shown in Figure 3.1 below. Figure 3.1 Location of Adamus Resources Limited Source: Knight Piesold (2007). University of Ghana http://ugspace.ug.edu.gh 36 3.1.2 Natural and Physical Environment 3.1.2.1 Climate The climate of the project area is hot and humid and can be classified as wet semi- equatorial (Lacombe et al., 2012). The Inter Tropical Convergence Zone (ITCZ) crosses the area twice a year, resulting in a bimodal rainfall pattern with peaks in March – July and September to October. The dry season is from November to February and the climate is heavily influenced by the dry, dust-laden northwest trade wind (Harmattan) which blows down from the Sahara Desert (Gyampoh et al., 2008). 3.1.2.2 Rainfall Rainfall data for the period of 2000-2006 from the environmental obtained from the offi ce of the environmental department of Adamus Resources are presented in Table 3.1 Table3.1: Monthly Average, Maximum and Minimum Rainfall Values of Project Area (2000-2006). Month Average Rainfall Minimum Maximum January 39.5 0 179.1 Feb.ruary 60.5 0 267.1 March 115.3 12 233.4 April 175.4 45.4 380.1 May 334.2 89.4 1016.5 June 561.7 198.9 1499.3 July 204.1 7.2 1096.1 August 78.1 3.6 510.2 September 91.8 2.4 465.8 October 214.4 26.2 1480.6 November 156.3 16.7 743.2 December 70.0 0 248.9 Annual Total 2,101.1 Source: Knight Piesold (2007) University of Ghana http://ugspace.ug.edu.gh 37 June is the wettest month of the year with an average rainfall of 561.7 mm, while January is the driest month with an average rainfall of 39.5 mm. The average number of rain days per month ranges from 3 in January to 22 in May. 3.1.2.3 Temperature and Evapo-transpiration Mean daily temperature of the project area varies between 25.0 and 30.8 oC with August reporting the minimum and September recording the maximum. Mean monthly potential evapo-transpiration values range between 51.5 mm in August and 86.3 mm in March. Mean annual potential evapo-transpiration is around 857 mm as per data obtained from the mine. Summary of monthly temperature and Potential Evapo- transpiration values are presented in Table 3.2. Table3.2: Average Monthly Temperature of Project area Month Temperature(oC) Potential Evaporation(mm) January 26.8 79.1 February 27.6 84.1 March 27.7 86.3 April 27.6 83.6 May 26.9 73.6 June 26.0 62.8 July 25.3 56.9 August 25.0 51.5 September 30.8 54.2 October 26.1 64.3 November 26.6 79.2 December 26.7 81.1 Source: Nzema Gold Mine- Environmental Department (2015) University of Ghana http://ugspace.ug.edu.gh 38 3.1.2.4 Local Geology and Soils Basement exposure is generally poor within the Project area and is largely restricted to road cuttings, a few stream beds, prospecting pits and trenches, and drill pads (Dzibodi-Adjimah, 1993). Laterite and mottled clay zones are locally developed on ridges, and saprolite typically extends to 10 – 30 metres beneath surface and locally as much as 80 m. The eastern part of the Project is largely underlain by Birimian volcanic and volcaniclastic rocks assigned to the Ashanti Belt, the western part mainly by Birimian metasedimentary rocks of basin and basin margin affinity in the southeastern corner of the Kumasi Basin (Dzibodi-Adjimah, 1993). The Birimian volcanics are thought to be faulted against the Tarkwaian Group immediately northeast of the current tenure, and a small area of quartz-rich fluvial rocks immediately east of Axim may also belong to the Tarkwaian. A large biotite ganite body is exposed in the western part of the Project area and probably belongs to the Cape Coast suite (Leube et al., 1990). Two large, magnetically zoned Dixcove-type granitoid batholiths intrude the volcanics at the eastern edge of the Project, and curved magnetic ridges adjacent to these intrusives could represent contact aureoles (Dzigbodi- Adjimah, 1993). Several narrow granitoid dykes and fault slivers up to 13 kilometres long and 700 metres thick of uncertain affinity are scattered through the Project area, and some near-circular geophysical features (electromagnetic resistors with weakly magnetic edges) between 1.5 and 2.0 km diameter, northeast of Anwia may represent subsurface plutons (Knight Piesold, 2007). Two north-striking doleritic dykes are known from geophysics and drilling in the Nkroful-Anwia area. There is no formal subdivision of the Birimian Supergroup in the Southern Ashanti University of Ghana http://ugspace.ug.edu.gh 39 area but several lithologically and geophysically distinct units can be identified and three litho-structure domains are recognised: Avrebo, Salman and Anwia. The soils of the Project area have developed over the sediments of the Lower Birimian rocks and belong to the Boi Soil Association (Knight Piesold, 2007). The soils are deeply weathered and intensively leached of bases rendering them acidic and low in fertility according. The series members of the Association within the Project site according to a study by Knight Piesold (2007) are the Omappe, Boi, Bremang and Oda series. The commonest features of the soils of the site are their great depths, strong brown to yellowish colour, acidic reaction, moderate fertility levels, high nutrient levels, clayey texture, sticky and plastic consistence and high contents of hard fresh quartz gravels and stones resulting from the weathering of quartz veins embedded in the subsoil (Dzigbodi-Adjimah, 1993). 3.1.2.5 Hydrogeology and Hydrology The aquifers are predominantly fractured leaky to confined, and the static water level tends to follow the topography, as observed in the drilled characterization boreholes ( Ku m a , 2 0 0 7 ) . The project area is comprised of predominantly metamorphic rocks, namely greywackes and phyllites. Intrusive granitoid domes also outcrop in the central part of the area, with few dolerite dykes intruding on the Anwia ore body (Kuma & Younger, 2004). The main groundwater flow in the area is through fractures, weathered zones and shear zones as a result of the relatively low matrix porosity of greywackes and phyllites. The hydrogeological setting is, therefore expected to have high transmissivity but low storativity values (Dapaah-Siakwan & Gyau-Boakye, 2000). Aquifer test analyses by Knight Piesold (2007) showed that the transmissivity, University of Ghana http://ugspace.ug.edu.gh 40 storativity and yield of the aquifers in the project area are highly variable which is typical in a fractured aquifer. The drainage of the area of influence is dominated by the Ankobra River to the east and the Amansuri Lagoon to the west. A smaller drainage, known as the Biare catchment flows to the south into the Atlantic Ocean (Kuma, 2007). The Ankobra River forms a significant part of the southwestern drainage of Ghana, draining a catchment area of approximately 8,300 km2. A number of smaller streams on the eastern side of the area of influence drain directly into the Ankobra River. These streams include the Kokweiba, Tika and a number of other un- named tributaries. These rivers drain the villages of Salman and Akanko (Yidana et al., 2008). The western side of the area of influence is drained by a number of rivers, which lead into the Amansuri Wetland System. The eastern half of the Amansuri Wetland catchment comprises the Broma and Subele Rivers, which later becomes the Franza River (Kuma, 2007). These rivers drain the villages of Teleku Bokazo, Anwia and Nkroful. The Amansuri Wetland at the mouth of the river has been identified as a site of internationally significant biodiversity. The Biare Catchment drains directly into the Atlantic Ocean to the south. This drainage, which is referred to as the Biare catchment, comprises a number of smaller streams including the Anuaye, Ngontubile, Wowule, Kokokulo and Eliabrazule (Yidana et al., 2008). This drainage includes the village of New Aluku. The numerous minor streams in the area which show dendritic drainage pattern suggest low percolation but high incidence of runoff and / or flooding during the rainy season (Knight Piesold, 2007). Most of the streams in the area of influence are utilised for domestic and economic purposes. A number of illegal artisinal mining activities occur within the Broma and Subele basins while the minor University of Ghana http://ugspace.ug.edu.gh 41 catchments of Anuaye, Ngontubile and Wowule are known for kaolin extraction. Other activities include recreation, fishing and palm wine distillation according to Environmental Impact Assessment (EIA) conducted by Kinght Piesold (2007). 3.2 Design and Construction Background of the Nzema Tailings Storage Facility The TSF was constructed in the year 2010 and is a cross-valley type impoundment located immediately due north of the plant site. It was designed by Knight Piesold (KP) Consulting to store tailings at a maximum capacity of 18 million tonnes. The storage is created by the construction of a main confining embankment across the valley some 2 km downstream of the treatment plant site (Knight Piesold, 2007). Tailings are deposited into the facility by multi-point spigot discharge from the main embankment and small east-west trending saddle dam. This deposition pattern will result in a tailings surface that slopes downwards to the south where the supernatant pond is formed remote from confining embankments (Vick, 1990). A series of decant towers are constructed in the southern part of the facility from which supernatant water are reclaimed and returned to the plant site. An under-drainage system is constructed within the basin area to minimize seepage to the local groundwater (Azcue et al., 1994). The system comprises a series of drainage pipes, surrounded by sand drainage material laid on the basin floor. Water intercepted and collected by the system is drained to a sump located immediately upstream of the main embankment. A groundwater drain system is also in place and this comprises a 160 mm diameter drain-coil pipe in a 1m2 cross-section of clean crushed granite aggregate which is surrounded by geo-textile and backfilled with compacted clay prior to constructing the impervious compacted clay soil liner. University of Ghana http://ugspace.ug.edu.gh 42 The technical justification for the ground water drainage system is based on the principles of groundwater hydrology, namely that the water table in the hills surrounding the TSF is draining by gravity through the fractured and weathered rocks to come to surface in the stream bottoms and then drain by gravity on surface (Rico et al., 2008). The groundwater is conveyed under the soil liner by a drainage system to avoid uplift and penetration of the liner. The ground water drain is expected to yield less and less water over time as the recharge area is progressively reduced by the increasing area of the liner in the catchment and as the stored water in the hills is slowly drawn down over time (Davies, 2000). Water intercepted and collected by the ground water drain system is drained to a sump located immediately upstream of the main northern embankment. Emergency spillways are constructed at each stage of facility development in the vicinity of a north-south trending saddle dam. A final spillway has been located in the small saddle, some 400 m south west of the plant site. The decant system for the facility comprises series of decant towers. The towers are located in the southern part of the facility. The two towers were constructed from pre-fabricated slotted concrete pipe and surrounded by coarse free draining rock-fill (Knight Piesold, 2007). A submersible pump is installed to pump water back to the plant via a High Density Ploy-Ethylene (HDPE) reclaim line along the decant access road. The pump and return water line systems is capable of removing water from the pond at a rate equivalent to maximum plant demand. The tailings delivery pipeline comprises a solid HDPE pipeline some 4,000 m long, located on the downstream side of the TSF access road. The alignment of the University of Ghana http://ugspace.ug.edu.gh 43 pipeline is such that any leakages from the line, due to a rupture or pipe break, will flow directly into the TSF and thus be contained. The TSF pipeline containment bund is fully lined with felt pad membrane. The future embankment raise is a downstream method. Design parameters are shown in the table below. Table3.3: TSF Design Parameters PARAMETERS DESIGN/CONSTRUCTION Total storage required 18.0Mt Life of mine 9 years Ore Processing Rate 2.0 Mtpa (Average) Plant Availability 92% (336 days/year) Tailings Beach Slope 1V:100 H (1%) Tailings Slurry- Percent Solid 45% (Oxide) 55% (Suphide) Source: Adamus Resources Limited (2015) 3.3 Methods 3.3.1 Study Design Water samples were collected between June and December 2014 from seventeen (17) sampling sites including the TSF decant water (TSF-DW), three (3) streams, a water storage dam, a pond and eleven (11) groundwater monitoring boreholes within 500 m radius of the mines Tailings Storage Facility. The data obtained were subjected to descriptive statistical analysis (95% confidence limit) and a correlation matrix was generated for parameters analyzed within the different media. Analysis of variance (ANOVA) was used to determine the level of differences between the various parameters sampled from the various sampling sites. When P-value is <0.05, it indicates a significant difference and p>0.05 indicates no significant difference. Microsoft Excel 2010 and EQwin data management software was used in statistical analysis University of Ghana http://ugspace.ug.edu.gh 44 conducted in the study. A structured questionnaire was the main research tool that was used to collect data on the views of people living close to the tailings dam on how the TSF has impacted on the quality of their water sources. 3.3.1.1 Groundwater Monitoring Borehole Locations and Surface Water Sampling Sites Ground and surface water sampling locations were carefully selected to reflect the potential impacts of ARL’s TSF on water resources within its catchment. Closeness of these sampling sites to the TSF makes them susceptible to pollutants through leachates and seepage from the facility. Four (4) groups of two monitoring boreholes and three single deep boreholes have been strategically installed by the mine at the northern and eastern embankment to to monitor possible seepage of contaminants from the TSF. Each monitoring borehole pair consists of one shallow borehole, extending through approximately 5 - 10 m of the near surface horizon and one deep borehole terminating at approximately 25 m. The monitoring boreholes comprise 100 mm PVC pipe, with a 3m slotted tip wrapped in geotextile. The boreholes are all capped with plastic material and locked to avert possible contamination of its content from external sources. In all, there are eleven (11) groundwater monitoring boreholes located at various points down gradient of the operating TSF of Nzema Gold Mine, which were sampled. The shallow boreholes are designed to detect seepage flowing within the surface sediment whilst deep boreholes monitor the chemical composition of groundwater. Locations of the monitoring boreholes were informed by initial hydrological studies conducted prior to operation to the TSF by an independent engineering firm (Knight University of Ghana http://ugspace.ug.edu.gh 45 Piesod) and recommendations from Ghana EPA. The water storage Dam (WSD) shares boundary with the southern embankment of the Tailings Storage Facility. Pond besides Water Storage Dam (PWSD) is a pond 80 m uphill of the TSF at the south and 8 m away from the WSD. It used to be a stream that traverses the existing location of the TSF and the WSD before its construction and was later dammed by the mine to make way for the construction of the TSF and the WSD. It is stagnant and does not have and vertical flow. TSF North-West Stream (TSF-NWS) is located just at the toe of the TSF northwestern embankment about 10 m away from the facility. It recharges from a cocoa farm located on a hill at the west of TSF and drains eastwards. The stream channel is about 4 m wide and 0.5 m deep and flows in a dendritic pattern. Angajale Stream (ANG) is located further northeast of the TSF and flows to join other streams which finally end up in the Ankobra River. It is monitored by the mine for surveillance purposes on monthly basis. The Angajale stream flows downstream of the TSF in the northeast direction. The stream passes through the Angajale and Akango communities. It serves as the main source of water for farming and domestic chores for the community folks. Sampling point coded BAN-T is a perennial stream that flows in an easterly direction down gradient of the TSF North Embankment. It flows through Akango to join the Ankobra River. All surface and groundwater bodies studied were within 500 m radius of the TSF. Coordinates of the sampling sites in the study have been listed in Table 3.4. University of Ghana http://ugspace.ug.edu.gh 46 Table3.4: GPS Coordinates of Sampling Sites Groundwater Sampling Site Code Name Latitude Longitude TSF Monitoring Bore 02A TSF MB02A N 50 1’ 13.9’’ E -2’ 15’ 5.3’’ TSF Monitoring Bore 02B TSF MB02B N 50 5’14.2’’ E -2’ 15’ 5.4’’ TSF Monitoring Bore 03A TSF MB03A N 50 1’ 6.1’’ E -2’ 14’ 50.8’’ TSF Monitoring Bore 03B TSF MB03B N 50 1’ 6.0’’ E -2’ 14’ 51.0’’ TSF Monitoring Bore 04B TSF MB04B N 50 1’ 3.5’’ E -2’ 14’ 44.5’’ TSF Monitoring Bore 04A TSF MB04A N 50 1’ 3.7’’ E -2’ 14’ 44.5’’ TSF Monitoring Bore 05 TSF MB05 N 50 1’ 10.6’’ E -2’ 14’ 50.8’’ TSF Monitoring Bore 07 TSF MB07 N 50 1’10.9’’ E -2’ 14’ 43.4’’ TSF Monitoring Bore 06 TSF MB06 N 50 1’ 15.6’’ E -2’ 14’ 51.7’’ TSF Monitoring Bore 08B TSF MB08B N 50 0’ 49.2’’ E -2’ 14’ 33.7’’ TSF Monitoring Bore 08A TSF MB08A N 50 0’ 48.9’’ E -2’ 14’ 33.7’’ Water Storage Dam WSD N 50 0’ 47.9’’ E -2’ 30’ 47.6’’ Pond Besides WSD PWSD N 50 16’ 29.0’’ E -2’ 30’ 50.5’’ TSF Northwest Stream TSF-NWS N 50 1’11.98’’ E -2’ 15’ 5.2’’ Angajale Stream ANG N 50 1’44.5’’ E -2’ 14’ 10.4’’ Bangara Stream BAN-T N 50 1’10.0’’ E -2’ 14’ 43.4’’ TSF Decant Water TSF-DW N 50 1’ 48.4’’ E -2’ 15’ 3.4’’ Source: Project Work, 2015 University of Ghana http://ugspace.ug.edu.gh 47 3.3.1.2 Selection of Water Quality Parameters Ghana EPA conventional pollutants for the mining sector were used as water quality parameters for the study. These parameters are closely associated with water pollution as a result of leachate from gold mines TSFs. They include BOD, true colour, electrical conductivity, pH, TDS, TSS, dissolved arsenic, dissolved cadmium, dissolved copper, dissolved mercury, free cyanide, total cyanide and WAD cyanide. These parameters are monitored on monthly basis by the mine and results are reported to the EPA in line with compliance of environmental permit conditions. 3.3.1.3 Sampling Frequency Water samples were collected on monthly basis consecutively from first week of June 2014 to the first week of December 2014. The sampling matrix was designed to capture both dry and wet seasons to ascertain the quality of water in the two key seasons experienced over the project area. 3.4 Sample Collection and Analysis Prior to collection of water samples, the Horiba Multi-parameter (U-52) probe used for in-situ surface and groundwater quality analysis was calibrated with 500 ml of HORIBA 100-4 pH standard solutions, as per the equipment’s operating manual. Standard latex gloves were always worn and disposed of after sampling at each sampling site to avoid cross contamination. Proper well purging before collection of samples is fundamental to successful ground water sampling. This ensures that the ground water sampled is of good quality and reflects natural conditions (Singh et al., 2004). In that regard, purging was done with the aid of portable generator set and submersible pump. Boreholes were purged for 5-10 minutes. In some instances, University of Ghana http://ugspace.ug.edu.gh 48 bailers were used when the generator set was faulty. Surface water samples were taken from below the surface (75 mm minimum) of the surface water in flowing streams. Care was taken not to include any surface film in the water collected. Containers were slowly and gently filled to avoid contamination of sampled water and disturbance of the water during sampling. Samples bottles were made to face the flow direction of water bodies. Air bubbles were eliminated and the bottles capped tightly to prevent contamination and water spilling. In order to avoid errors and mix-ups of samples, sample bottles were labeled with permanent, legible markings with the following information: Sample location or code, date and time, Parameters for analysis, and Preservatives, if any (Parizek, & Lane, 1970). Preservation methods are limited to: pH control, chemical addition, and refrigeration. The following parameters were preserved as follows: Metals: - Conc. HNO3 to pH < 2, after filtering with 0.45-micron filter; Cyanide: - NaOH to pH > 12 (filter if turbid or TSS present). Samples were packed upright in a cooler with ice packs to maintain the temperature of the samples just above freezing. A sample submission form (chain of custody) was filled out with all of the above information plus comments pertinent to the sample and transported to the laboratory for analysis. 3.4.1 In-situ Measurements TDS, pH, BOD and electrical conductivity were measured in-situ using Horiba multi parameter probe (Model No. Horiba 500, S/N). The probe was rinsed with distilled water after every measurement to avoid cross contamination. The most stable reading displayed by the probe was taken to be the actual reading. All samples collected were sent to SGS Mas laboratory at Tema for analysis. Analyses of water samples were University of Ghana http://ugspace.ug.edu.gh 49 carried out in line with strict laboratory standards and internationally accepted protocols. 3.4.2 Analysis for Cyanide (CN) The titrimetric method as outlined by Bradbury et al. (1991) was used for the analysis of CN species. A blank solution was titrated against standardized 0.1M AgNO3 solution using p-dimethylamino benzalrhodanine indicator solution, until the colour of the indicator changed from cannary yellow to salmon blue. The blank titre was recorded and subsequently used. 100 ml of the sample was titrated against 0.1 M AgN03 using 5ml of p- dimethylaminobenzalrhodanine as an indicator to the end point. Concentrations of total cyanide in the water samples were determined by distillation of the sample to which 10 ml of conc. HCl and 10 ml of 12 % w/v hydroxylamine hydrogen chloride solution had been added to generate hydrogen cyanide gas (HCN), which was absorbed into 2 M NaOH solutions. The resulting sodium hydroxide solution was further diluted to 250 ml out of which 100 ml was titrated against standardized 0.1 M AgNO3 solution using 5 ml of p-dimethylaminobenzalrhodanine indicator to the salmon blue end point (Kuhn &Young, 2005). Concentrations of free and total cyanide in the samples were calculated as follows: CN- mg/l = (A-B)/100 ml * (250/1000) ml where A – sample titre volume of AgNO3 and B – blank titre volume of AgNO3 3.4.3 Total suspended solids analysis (TSS) The photometric (non-filterable residue) method was used. 500 ml of sample was blended at high speed for two minutes. This was poured into a 600 ml beaker, stirred and 25 ml immediately poured into a sample cell. The stored programme number for University of Ghana http://ugspace.ug.edu.gh 50 suspended solids, 630, was entered. The wavelength was set to 810 nm. A sample cell was filled with 25 ml de- mineralized water (blank). This was placed in the cell holder and standardized. Next the sample was placed into the cell holder and the reading taken in mg/l suspended solids. 3.4.4 Dissolved Metals Metals in the water samples collected were determined using atomic absorption spectro- photometer (AAS), AAS 220 model. The samples for AAS were first digested with nitric acid before analysis. In the laboratory, the acidified samples were filtered using Whatman’s filter paper. The 0.45μm membrane filter paper was used because the analyte of interest in this work is the total dissolved metals. The filtered samples and the unfiltered samples were stored in the refrigerator at 4 0 C for further analysis (Serfor- Armah et al., 2006). 3.5 Quality Control and Quality Assurance In order to ensure the quality of the data, field and laboratory procedures were optimized. In this vein, sampling bottles were properly washed with dilute hydrochloric acid and later rinsed with de-ionized water in the laboratory prior to the field sampling. At each sampling location, the bottles were rinsed with the water to be collected to eliminate any introduced contamination. Replicate samples were collected at some stations to inform of any procedural errors in the laboratory. University of Ghana http://ugspace.ug.edu.gh 51 3.6 Questionnaire Administration To solicit the views of inhabits in the catchment area of the mine’s tailings facility on the potential impacts of the TSF on the surface and groundwater resources, questionnaires were administered randomly to some residents in three selected communities in close proximity to the TSF. Among others, the questionnaires sought to investigate the perception of community members on qualitatively observed surface and groundwater parameters including colour and odour as well as their awareness on the tailings facility possible environmental impacts. Out of the total of one hundred and twenty questionnaire distributed, one hundred people responded. University of Ghana http://ugspace.ug.edu.gh 52 CHAPTER FOUR RESULTS 4.1 Physical Parameters of TSF Decant Water (TSF-DW) 4.1.1 pH The pH of TSF-DW in the study ranged between 7.4 and 8.9 (Appendix IA). The highest pH was recorded in the month of December with August and September recording the lowest (Figure 4.1). Mean pH of 8.2 within GHEPA effluent guideline limit (6-9) was recorded for TSF-DW in study. Figure 4.1 pH of TSF- DW Samples Collected Between June and December, 2014 compared with GHEPA Upper and Lower Limits (2013). 8 8.3 7.4 7.4 8.9 8.6 8.9 0 1 2 3 4 5 6 7 8 9 10 Jun Jul Aug Sep Oct Nov Dec p H pH of TSF Decant Water GHEPA Guideline Upper Limit GHEPA Guideline Lower Limit Month University of Ghana http://ugspace.ug.edu.gh 53 4.1.2 Electrical Conductivity (EC) Electrical conductivity of TSF-DW in the study ranged between 1340 and 1630 µS/cm (Appendix IA). Highest EC was recorded in the month of December and the lowest in July (Figure 4.2). Mean EC of TSF-DW recorded for the study was 1507.1 µS/cm and is slightly above GHEPA guideline (1500 µS/cm) for effluent discharge. Figure 4.2 EC of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 1600 1340 1380 1470 1590 1540 1630 0 200 400 600 800 1000 1200 1400 1600 1800 Jun Jul Aug Sep Oct Nov Dec EC ( µ S/ cm ) EC of TSF Decant Water WHO Guideline Limit Month University of Ghana http://ugspace.ug.edu.gh 54 4.1.3 Total Dissolved Solids (TDS) Total Dissolved Solid of TSF-DW ranged between 861 and 1040 mg/l (Appendix IA). Maximum TDS was recorded in the month of December and minimum in July. Mean TDS of 964.5 mg/l well within GHEPA guideline for effluent discharge was reported for TSF-DW in the study. Figure 4.3 TDS of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 1020 861 886 940 1020 985 1040 0 200 400 600 800 1000 1200 Jun Jul Aug Sep Oct Nov Dec TD S (m g/ l) TDS of Tailings Decant Water GHEPA Guideline Limit Month University of Ghana http://ugspace.ug.edu.gh 55 4.1.4 Biological Oxygen Demand (BOD) Biological Oxygen Demand recorded for the TSF-DW was below laboratory detection limit in the entire study. 4.1.5 Colour Values of true colour ranged between <3 and 40 TCU (Appendix IA). Maximum value of colour was recorded in the month of October whereas the minimum was reported in the month of November (Figure 4.4). Mean colour of 9.40 TCU far below GHEPA guideline limit for effluent discharge was reported for TSF-DW in the study. Figure 4.4 True Colour of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 5 5 5 5 41 <3 5 0 20 40 60 80 100 120 140 160 Jun Jul Aug Sep Oct Nov Dec Tr u e c o lo u r True colour GHEPA Guideline Limit Month University of Ghana http://ugspace.ug.edu.gh 56 4.1.6 Total Suspended Solids (TSS) Total Suspended Solids values of TSF-DW ranged between 19 mg/l and 105mg/l as shown in (Appendix IA). Highest TSS was recorded in the month of July and the minimum in October (Figure 4.5). Mean TSS of 55.29 mg/l above GHEPA Guideline limit of 50 mg/l was reported for TSF-DW in the study. Figure 4.5 TSS of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 91 105 41 36 19 40 55 0 20 40 60 80 100 120 Jun Jul Aug Sep Oct Nov Dec TS S (m g/ l) TSS of TSF-DW GHEPA Guideline Limit Month University of Ghana http://ugspace.ug.edu.gh 57 4.2 Chemical Parameters of TSF Decant Water (TSF-DW) 4.2.1 Total Cyanide (CN-t) Total cyanide concentration in TSF-DW ranged between <5 and 1.55 mg/l (Appendix IA). The highest concentration, 1.55 mg/l was recorded in the month of June and the lowest below laboratory detection limit (<5 mg/l) recorded in December as shown in Figure 4.6. Total cyanide recorded in June was above EPA guideline for effluent discharge. Mean CN-t concentration of 0.586 mg/l below recommended GHEPA threshold of 1 mg/l was recorded for TSF-DW in the study. Figure 4.6 Total Cyanide of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 1.55 0.031 0.32 0.38 0.72 0.52 <0.005 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 Jun Jul Aug Sep Oct Nov Dec To ta l C ya n id e ( m g/ l) GHEPA Guideline Limit Total Cyanide of TSF-DW Month University of Ghana http://ugspace.ug.edu.gh 58 4.2.2 Free Cyanide (CN-f) Free cyanide concentration in the TSF-DW varied between <0.005 and 1.04mg/l. Highest CN-f concentration was recorded in the month of June with September and October recording minimum values below laboratory detection limit (Figure 4.7). Mean CN-f concentration of 0.38mg/l above recommended regulatory (GHEPA) limit of 0.2 mg/l was reported for the study (Appendix IA). Figure 4.7 CN-f of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 1.04 0.02 0.07 0.06 <0.005 <0.005 0.71 0 0.2 0.4 0.6 0.8 1 1.2 Jun Jul Aug Sep Oct Nov Dec Fr e e C ya n id e ( m g/ l) Free Cyanide of TSF-DW GHEPA GuidelineMonth University of Ghana http://ugspace.ug.edu.gh 59 4.2.3 Weak Acid Dissociable Cyanide (CN-WAD) Values of CN-WAD recorded during the sampling period ranged between <0.005 and 1.04mg/l (Appendix IA). Highest concentration was recorded in June while October, November and December recorded the lowest concentration below laboratory detection limits as shown in Figure 4.8. Mean WAD cyanide concentration of 0.342 mg/l below GHEPA effluent discharge limit (0.6 mg/l) was reported in the study. Figure 4.8 WAD Cyanide of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 1.04 0.03 0.08 0.23 <0.005 <0.005 <0.005 0 0.2 0.4 0.6 0.8 1 1.2 Jun Jul Aug Sep Oct Nov Dec W A D C ya n id e (m g/ l) WAD Cyanide of TSF-DW GHEPA Guideline Limit Month University of Ghana http://ugspace.ug.edu.gh 60 4.2.4 Arsenic Arsenic concentration in TSF-DW ranged between 0.17 and 5 mg/l . Highest dissolved arsenic concentration of 5 mg/l was recorded in the month of June whereas the lowest, 0.17 mg/l was recorded in August. Mean Arsenic concentration of 1.26 mg/l far above GHEPA Guideline limit of 0.1 mg/l was recorded for TSF-DW during the study. Arsenic concentration exceeded regulatory guideline limits in all months sampled as shown in Figure 4.9. Figure 4.9 Dissolved Arsenic of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 5 0.52 0.17 0.39 0.79 0.85 1.1 0 1 2 3 4 5 6 Jun Jul Aug Sep Oct Nov Dec A rs en ic (m g/ l) Arsenic in TSF-DW GHEPA Guideline Limit Month University of Ghana http://ugspace.ug.edu.gh 61 4.2.5 Copper Values of copper recorded for TSF-DW ranged between 0.058 and 0.35 mg/l (Appendix IA). Highest concentration was recorded in the month of June whereas the lowest was recorded in July (Figure 4.10). Mean copper concentration of 0.15 mg/l far below GHEPA guideline of 5 mg/l for effluent discharge was reported in the study. Figure 4.10 Mean Dissolved Copper of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 0.35 0.058 0.082 0.071 0.145 0.077 0.249 0 1 2 3 4 5 6 Jun Jul Aug Sep Oct Nov Dec C o p p er ( m g/ l) Dissolved Copper in TSF-DW GHEPA Guideline Limit Month University of Ghana http://ugspace.ug.edu.gh 62 4.2.6 Mercury Mercury concentrations recorded for TSF-DW ranged between <0.0001 and 0.0002 mg/l. Maximum concentration (0.0002 mg/l) was recorded in the months of July, October and November whereas June, August, September and December recorded the minimum (<0.0001 mg/l) as shown in Figure 4.11. Mean mercury concentration of 0.002 mg/l well within GHEPA guideline limit (0.006 mg/l) was recorded. Figure 4.11 Mean Dissolved Mercury of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). <0.0001 0.0002 <0.0001 <0.0001 0.0002 0.0002 <0.0001 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 Jun Jul Aug Sep Oct Nov Dec M er cu ry ( m g/ l) Mercury Concentration in TSF-DW GHEPA Guideline Limit Month University of Ghana http://ugspace.ug.edu.gh 63 4.2.7 Cadmium (Cd) Concentration of cadmium in TSF-DW varied between 0.0001 and 0.0004 mg/l. Maximum concentration was recorded in December and the minimum recorded in July (Figure 4.12). Mean cadmium concentration for TSF-DW of 0.0002mg/l well within the GHEPA guideline for effluent discharge (0.1mg/l) was reported in the study. Figure 4.12 Mean dissolved Cadmium of TSF-DW Samples Collected Between June and December, 2014 compared with GHEPA Guideline limit (2013). 0.0002 0.0001 0.0002 0.0002 0.0002 0.0002 0.0004 0 0.02 0.04 0.06 0.08 0.1 0.12 Jun Jul Aug Sep Oct Nov Dec C ad m iu m ( m g/ l) Cadmium Concentration in TSF-DW GHEPA Guideline Limit Month University of Ghana http://ugspace.ug.edu.gh 64 4.3 Physical Parameters of Groundwater within 500m radius of the TSF 4.3.1 pH Values of groundwater pH varied between 6 and 7.64. TSMB 03B recorded the highest pH of 7.64 with TSFMB 04A and TSFMB04B recording pH of 6 as the lowest (Figure 4.13). There was a significant difference (P <0.05) between the pH values of various groundwaters sampled (Appendix IB). Mean pH of 6.63 below baseline mean (6.8) but within WHO Guideline range for drinking water and GHEPA guideline for effluent discharge was recorded during study. Figure 4.13 Mean pH of Groundwater within 500m radius of the TSF sampled between June-December, 2014 compared with WHO Guideline (2011) and Baseline Mean 6.1 6.3 7.1 7.6 6.0 6.0 7.2 6.8 6.9 6.4 6.5 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 p H Groundwater Bores WHO Guideline Upper Limit WHO Guideline Limit Base Mean Monitoring Bore University of Ghana http://ugspace.ug.edu.gh 65 4.3.2 Electrical Conductivity (EC) Mean EC of groundwater varied between 114.7 and 441.8 µS/cm. The differences between the means were statistically significant (P < 0.05) as shown in Appendix IC. Mean EC of 233.8 µS/cm below baseline mean (312 µS/cm) and well within WHO Guideline limit for drinking water was recorded for groundwater around the TSF during the entire study. Figure 4.14 Mean EC of Groundwater within 500m radius of the TSF sampled between June-December, 2014 Compared with WHO Guideline (2011) and Baseline Mean. 129.4 190.9 441.9 373.7 114.7 128.1 362.7 190.9 208.6 134.0 187.0 0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0 EC ( µ s/ cm ) Groundwater Monitoring Boreholes WHO Guideline Limit Baseline mean Monitoring Bore University of Ghana http://ugspace.ug.edu.gh 66 4.3.3 Total Dissolved Solids (TDS) Total dissolved solids values in groundwater ranged between 74.8 and 285.8 mg/l (Appendix ID). Highest TDS was recorded in TSFMB 03A whereas TSFMB04A recorded the lowest (Figure 4.15). The difference between means of TDS of the monitoring bores was statistically significant (P<0.05). Average TDS of 146.8 mg/l below baseline mean (218 mg/l, Appendix IIF) and well within WHO guideline limit of 500 mg/ was recorded for the study. Figure 4.15 TDS of Groundwater within 500m radius of the TSF sampled between June- December, 2014 compared with WHO Guideline (2011) and Baseline Mean. 84.3 124.0 285.9 242.3 74.6 82.9 252.7 124.3 135.7 87.1 121.4 0.2 100.2 200.2 300.2 400.2 500.2 600.2 TD S (m g/ l) Groundwater Monitoring Boreholes WHO Guideline Limit Baseline Mean Monitoring Bore University of Ghana http://ugspace.ug.edu.gh 67 4.3.4 Total Suspended Solids (TSS) Highest TSS value of 29.57 mg/l was recorded in TSFM05 whereas TSFM08A recorded the lowest of 2.9 mg/l as shown in Figure 4.16. The difference between the means of groundwater was statistically significant (P<0.05). Mean TSS level for the entire study period was 10.01 mg/l, which is below with baseline mean (11.2 mg/l). Mean TSS for TSF monitoring bores 04B, and 05 were above baseline mean but consistent with regulatory applicable allowable limit of 50 mg/l. Appendix IE presents details of TSS values of groundwater monitoring boreholes within the catchment of the TSF. Figure 4.16 TSS Levels of Groundwater within 500m radius of TSF sampled between June-December, 2014 compared GHEPA Limit (2013) and Baseline Mean 10.6 8.3 5.4 4.4 8.4 23.9 29.6 7.6 4.7 2.3 5.0 0.0 10.0 20.0 30.0 40.0 50.0 60.0 TS S (m g/ l) Groundwater Monitoring Boreholes WHO Guideline Limit Baseline Mean Monitoring Bore University of Ghana http://ugspace.ug.edu.gh 68 4.3.5 Biological Oxygen Demand (BOD) and True Colour BOD and true colour recorded in all monitoring boreholes within the catchment of the TSF were below their respective laboratory detection limits in the study. 4.4 Chemical Parameters of Groundwater within 500m radius of the TSF 4.4.1 Arsenic (As) Mean arsenic values varied between 0.0005 and 0.0063 mg/l with TSFMB 03B and TSFMB 04A recording the highest and lowest concentrations respectively. Difference between the means was statistically insignificant (P>0.05) as shown in Appendix IF. Mean concentration of dissolved arsenic consistent with baseline mean was recorded in all monitoring bores during the sampling period except TSMB03B as shown in Figure 4.17. Mean concentration for groundwater within the catchment of the TSF for the entire study period was 0.0014 mg/l, which is within the WHO guideline limit of 0.01 mg/l for potable water. University of Ghana http://ugspace.ug.edu.gh 69 Figure 4.17 Dissolved Arsenic Concentration in Groundwater within 500m radius of the TSF compared with WHO Guideline Limit (2011) and Baseline Mean. 4.4.2 Copper Mean copper concentration ranged between <0.001 and 0.0026 mg/l (Appendix IG). Highest mean copper value of 0.0026 mg/l was recorded in TSFMB 04A with TSFMB 07 and TSFMB08A recording the lowest of <0.001 mg/l. The difference (P>0.005) between the means was statistically insignificant. Mean copper value of 0.0015 mg/l consistent with baseline mean and well within WHO Guideline was reported for entire study. Baseline means of surface and groundwater are presented in Appendix IIF. 4.4.3 Cyanide (Total, WAD and Free Cyanide), Cadmium and Mercury Cyanide (Total, WAD, and Free) concentrations were below laboratory detectable limits for all groundwater monitoring stations sampled during the entire study. 0.0006 0.0009 0.0025 0.0063 0.0005 0.0006 0.00096 0.0013 0.0006 0.0009 0.0006 0 0.002 0.004 0.006 0.008 0.01 0.012 A rs e n ic ( m g/ l) TSF Groundwater Monitoring Boreholes WHO Guideline Limit Baseline mean Monitoring Bore University of Ghana http://ugspace.ug.edu.gh 70 In a similar vein, mercury and cadmium concentration in all groundwater around the TSF during the entire study was below laboratory detection limit of <0.0001 mg/l. 4.5 Physical Parameters of Surface Water within 500m radius of the TSF 4.5.1 pH Maximum pH of 7.3 was recorded in the WSD with the minimum pH of 6.3 recorded in ANG stream. Statistically, the differences (P>0.05) between the means were not significant. Mean pH of surface water was within WHO guideline for potable water and similar to baseline mean as shown in Figure 4.18. Details of pH of various surface water bodies can be seen in Appendix IIA. Figure 4.18 pH of Surface Water within 500m radius of the TSF compared with WHO (2011) Guideline and Baseline mean. 7.3 6.8 6.5 6.3 6.5 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 WSD PWSD BAN-T ANG TSF-NWS p H WHO Guideline Lower Limit WHO Guideline Upper Limit Baseline Mean Surface water University of Ghana http://ugspace.ug.edu.gh 71 4.5.2 Electrical Conductivity (EC) Mean conductivity of surface water studied ranged between 55.54 and 185.71 µS/cm. Maximum conductivity was recorded at BAN-T stream and minimum at PWSD (Figure 4.19). The difference (P<0.05) between surface water EC was statistically significant. Mean conductivity of 116.82 µS/cm below WHO (2011) guideline limit of 500 µS/cm and baseline mean (203.8 µS/cm) was reported for surface water during the entire study. Figure 4.19 Electrical Conductivity of Surface Water within 500m radius of TSF compared with WHO (2011) Guideline and Baseline Mean 99.1 55.5 185.7 67.0 176.7 0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0 WSD PWSD BAN-T ANG TSF-NWS C o n d u ct iv it y (µ S/ cm ) WHO Guideline Limit Baseline Mean Surface Water University of Ghana http://ugspace.ug.edu.gh 72 4.5.3 Total Dissolved Solids (TDS) PWSD recorded the highest TDS of 990 mg/l whereas ANG recorded the lowest of 43.3 mg/l. Statistically, there was a significant difference (P>0.05) between the means of TDS recorded for various surface water studied. Total dissolved solids of PWSD was above the baseline mean (36.6) and WHO guideline limits for potable water but that of all other surface water were well within limits (Figure 4.20). Appendix IIC provides details of TDS of surface water measured. Figure 4.20 TDS of Surface Water within 500m radius of TSF compared with WHO (2011) Guideline and Baseline mean 64.4 990.0 78.3 43.4 103.1 0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 WSD PWSD BAN-T ANG TSF-NWS TD S (m g/ l) WHO Guideline Limit Baseline Mean Surface Water University of Ghana http://ugspace.ug.edu.gh 73 4.5.4 True Colour Maximum true colour of 13.4 TCU was recorded at ANG stream whereas the minimum of 1.4 TCU recorded at BAN-T as shown in Figure 4.21. Mean True colour of 4.7 TCU below WHO guideline limit for drinking water was reported for the study. Details of true colour of Surface water are shown in Appendix IID. Figure 4.21 True Colour of Surface Water within 500m radius of TSF compared with WHO (2011) Guideline and Baseline Mean 3.0 3.3 1.4 13.4 2.6 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 WSD PWSD BAN-T ANG TSF-NWS T ru e c o lo u r (T C U ) WHO Guideline Limit Baseline Mean Surface Water University of Ghana http://ugspace.ug.edu.gh 74 4.5.5 Total Suspended Solids (TSS) Total suspended solids varied between 10.71 and 990 mg/l. TSS of Surface water compared with baseline mean and Ghana Water Company (GWC) guideline are presented in Figure 25 below. Mean TSS of 230 mg/l recorded for the study is above GWC guideline and baseline mean. There is no WHO guideline for TSS. PWSD recorded the highest TSS of 990 mg/l with BAN-T recording the lowest of 10.71 mg/l (Figure 4.22). Statistically, the difference (P>0.05) between the TSS of various surface water was insignificant. Appendix IIE provides more information about Surface water TSS. Figure 4.22 TSS of Surface within 500m radius of TSF compared with GWC Guideline (2013) and Baseline mean 21.0 990.0 10.7 108.9 24.1 0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 WSD PWSD BAN-T ANG TSF-NWS TS S (m g/ l) Baseline Mean Ghana Water Company Guideline Limit Surface Water University of Ghana http://ugspace.ug.edu.gh 75 4.5.6 Biological Oxygen Demand (BOD) Biological oxygen demand below laboratory detection limit (<5 mg/ l) was recorded in all surface water bodies within the catchment of the TSF for the entire sampling period. 4.6 Chemical Parameters of Surface Water within 500 m radius of the TSF 4.6.1 Arsenic (As) Arsenic concentration in surface water varied between 0.001 and 0.021 mg/l. Highest mean concentration of arsenic above WHO (2011) guideline limit for potable water was recorded in PWSD and the lowest recorded in BAN-T and TSFNWS. The difference (P>0.05) between the means of surface water studied was statistically insignificant. Figure 4.23 presents dissolved arsenic concentration in surface water compared with baseline mean (0.003 mg/l) and WHO (2011) guideline limit for potable water. Figure 4.23 Arsenic Concentration of Surface Water within 500m radius of TSF compared with WHO (2011) Guideline and Baseline mean 0.004 0.021 0.001 0.009 0.001 0.000 0.005 0.010 0.015 0.020 0.025 WSD PWSD BAN-T ANG TSF-NWS A rs en ic (m g/ l) WHO Guideline Limit Baseline Mean Surface Water University of Ghana http://ugspace.ug.edu.gh 76 4.6.2 Copper (Cu) Maximum copper (0.0035 mg/l) was recorded at PWSD and minimum (0.001 mg/l) recorded at BAN-T. Statistically, the difference (P>0.05) between the means of various surface water sampling sites were insignificant. Mean copper concentration of 0.0020 mg/l consistent with baseline mean and well within WHO guideline limit of 2 mg/l was recorded during the study period. Figure 30 shows the means of copper compared with the baseline mean and WHO (2011) guideline limit for potable water. 4.6.3 Cyanide (Total, Free and WAD Cyanide), Mercury and Cadmium Total, Free and WAD cyanide concentrations recorded in surface water around the TSF were all below laboratory detection limit during the study. Similarly, Mercury and cadmium concentration were also below their respective laboratory limits was reported in the study. 4.7 Pearson’s Product Moment Correlation between Parameters 4.7.1 TSF Decant Water Pearson’s product moment correlation matrix carried out to determine the degree, strength and direction of the interrelationship between the parameters in TSF-DW revealed that pH had moderate positive relationship with mercury, with a correlation coefficient(r) of 0.56 as shown in Appendix IIIA. EC had a highly significant positive correlation with dissolved arsenic, cadmium and copper (EC-As, r = 0.5), EC-Cd, r = 0.6), EC-Cu, r = 0.72). EC also correlates moderately positive with free cyanide (EC- CN-f, r = 0.58). There was a strong positive correlation between TDS and cadmium as well as TDS and copper (TDS-Cd, r=0.67, TDS-Cu, r=0.71). However, a very University of Ghana http://ugspace.ug.edu.gh 77 weak negative correlation was reported between TDS and mercury (Hg) (TDS-Hg, r=-0.0122). There was also a moderate positive correlation between TDS and free cyanide as well as TDS and arsenic (TDS- CN-f, r= 0.56, TDS-As, r= 0.48). True colour had a weak negative correlation with dissolved Arsenic, cadmium, WAD and free cyanide (Appendix IIIA). Correlation between TSS and cadmium as well as dissolved mercury was weak and negative. (TSS-Cadmium, r=-0.29, TSS-Hg, r = - 0.018). 4.7.2 Groundwater A very strong negative correlation between groundwater pH and copper (pH-Cu, r =- 0.699) was reported. No defined relationship could be established between groundwater pH, mercury and cadmium because concentrations of these metals in groundwater were below their respective detection limits. Pearson’s Product Moment Correlation revealed that EC had a weak positive correlation with copper (EC-Cu, r = 0.29). The relationship of EC with arsenic was however weak and negative one (EC- As, r=-0.22). TDS had a strong positive correlation with copper (TDS-Cu, r=0.65). The correlation between TDS and arsenic was very weak and negative (TDS-As, r = - 0.097). There was no defined relation between TDS and cyanide (Free, WAD, and Total). This is because concentrations of cyanide in groundwater were below detection limit. Relationship between true colour and study parameters could not be established because true colour in groundwater reported in the study was below detection limit. University of Ghana http://ugspace.ug.edu.gh 78 4.7.3 Surface Water Pearson’s Product Moment Correlation revealed that Surface water pH had a very weak negative correlation with copper (pH-Cu, r = -0.16). The relationship between pH and other metals studied as well as cyanide could not be established as values recorded were below detection limits. EC of surface water had an insignificant positive correlation with copper (EC-Cu, r = 0.27) as shown in Appendix IIIC. Relationship between surface water EC and other study metals as well as with cyanide could not be defined owing to the same reason above. There was a strong positive correlation between TDS and copper (TDS-Cu, r = 0.88) as shown in Appendix IIIC. Surface water true colour had a weak negative correlation with dissolved copper (Colour- Copper, r=- 0.34). 4.8 Social Survey A total of 100 respondents out of the 120 questionnaires distributed, was made up of 30 from Angajele, 40 from Akango and 30 from Aluku were interviewed Figure 4.24 shows the percentage of distribution of respondents. With respect to sex of the individuals, 68 people representing 68% were males whilst 32 individuals representing 32% were females. University of Ghana http://ugspace.ug.edu.gh 79 Figure 4.24: Distribution of Respondents in the Study Area. Figure 4.25 indicates the ages of the respondents in the study area. Twenty- nine percent (29%) of the respondents were between the ages of 20 and 29 years, 28% between 30 and 39 and 22% between 40 and 49. Only 4% were above 60 years at the time respondents were interviewed. Figure 4.25: Age of Respondent in the Study Area. 29% 28% 22% 17% 4% 0% 5% 10% 15% 20% 25% 30% 35% 20-29yrs 30-39yrs 40-49yrs 50-59yrs >60yrs Age % o f R es p o n d en ts 30% 40% 30% Angajele Akango Aluku University of Ghana http://ugspace.ug.edu.gh 80 Similarly, on the occupation of the respondents in the study area, it was observed that eighteen percent (22%) of the respondents were students, 24% engaged in small scale mining and 25% and 29% engaging in some form of artisanship and farming respectively (Figure 4.26). Figure 4.26: Occupation of Respondents in the Study Area Majority (74%) of the respondents were settlers who have migrated from the three northern region of Ghana whilst 26% were indigenes. As part of the social appraisal, the educational levels of respondents were sought as it plays a significant role in comprehension of issues relating to environmental pollution. Twenty-one percent (21%) of the respondents had SSS/6th form education whilst majority (42%) had primary/JSS education. Seventeen percent (17%) had no form of formal education. Majority of respondents use streams as major source of water (68%), which are complemented with 29% 25% 24% 22% Farmers Artisans Small scale miners Students University of Ghana http://ugspace.ug.edu.gh 81 other sources such as hand dug wells and boreholes. Figure 4.27 below illustrates water sources accessed by respondents in the study area. Figure 4.27: Water Sources Accessed by Respondents in the Study Area. All respondents use water for domestic activities including cooking, drinking, bathing and washing. The water used for domestic chores are however not subjected to any form of pre-treatment before use. When the respondents were asked whether they were living in their respective communities before the construction and operation of the TSF, 87% answered in the affirmative whilst 13% said they were not. The respondents, however, said that the TSF has significantly impacted on their water resources. Five percent (5%) of the respondents related the impact to smell, 78% to colour and 17% to odour. 4% 4% 68% 24% Hand dug-well borehole stream borehole, stream and well University of Ghana http://ugspace.ug.edu.gh 82 Figure 4.28: Views of Respondents on the Impact of Tailings Storage Facility on Water Sources When the respondents were asked whether they had been sensitized by the mine on possible environmental and health impact of TSF, majority (83%) said no whilst the remaining 17% answered in the affirmative. The respondents made suggestions that the mine authorities should provide them with potable water. They also advocated for regular monitoring of existing water resources for early identification issues of public health concerns. 78% 5% 17% Colour smell odour University of Ghana http://ugspace.ug.edu.gh 83 CHAPTER FIVE DISCUSSION 5.1 Physical Parameters The mean pH of the Tailings Decant Water was slightly alkaline (8.2) and within GHEPA allowable limit for effluent discharge. Acheampong et al. (2013) reported similar mean pH (8.1 - 8.3) in TSF water at Bogoso mine. The slightly alkaline pH of the TSF water could be attributed to addition of lime during the beneficiation process at Adamus Resources Limited. On the contrary, the mean pH of ground and surface water (6.67 and 6.63 respectively) within the catchment of the TSF were near neutral and well within WHO guideline for potable water. Water bodies studied recorded pH consistent with their respective baseline means (6.8 and 6.6 for surface and groundwater respectively). The results of the study suggest that pH of the TSF water would not adversely affect the surrounding natural water bodies and their life forms. The slightly alkaline pH of the Tailings Decant Water also suggests that the tailings of ARL is not acid generating. There is therefore a very low probability of catchment water bodies being contaminated as a result Acid Mine Drainage (ARD). According to Shinoda et al. (2013), EC of water depends on the quantity of dissolved salts present and for dilute solutions it is approximately proportional to the total dissolved solid (TDS) content. The presence of dissolved salts in water increases its electrical conductivity, which varies according to the temperature. Mean electrical conductivity for the TSF-DW (1147.6 µS/cm) recorded during the study is above University of Ghana http://ugspace.ug.edu.gh 84 WHO limit of 500 µS/cm. Conversely, relatively low mean EC of 116.8 µS/cm and 223.8 µS/cm were recorded for surface and groundwater respectively. These values are well within WHO guideline for potable water and below baseline values (312.8µS/cm and 203.88µS/cm respectively). This suggests that the TSF does not have a negative impact on surrounding water bodies as far as conductivity is concerned. High EC in TSF-DW could be attributed to free ions originating from reagents such as HCL used in the ore treatment process. Electrical conductivity was however, relatively high in ground water than in surface water. The TSF-DW recorded high mean TDS of 964.6mg/l which is above the WHO limit of 500mg/l for potable water. On the other hand, ground and surface water recorded relatively low TDS of 146.3mg/l and 255.8mg/l respectively and were within WHO guideline. This suggests that high TDS of TSF has not impacted on the surrounding water bodies. Mean Biochemical Oxygen Demand ( BOD) in all media studied were below detection limit. This observation suggests that organic contamination was non- existent in the media studied. Biochemical oxygen demand is an estimate of the quantity of oxygen used by microorganisms such as aerobic bacteria in the oxidation of organic matter (Preininger et al., 1994). Mean true colour of the TSF-DW measured in this study was well within maximum allowable limit recommended by GHEPA. Groundwater recorded true colour (<5 TCU) below detection limit. Surface water bodies around the TSF recorded mean true colour of 4.7 TCU below baseline mean of 5 TCU and well within GHEPA limit of 150 TCU. There is no WHO guideline for true colour. Results gathered from the study suggest that true colour of TSF water and water bodies within its catchment are independent of each other. University of Ghana http://ugspace.ug.edu.gh 85 Mean TSS (55.3 mg/l) of the TSF-DW, which was recorded during the study, was above GHEPA limit of 50 mg/l for effluent discharge. There is no WHO guideline available for TSS. Spikes in TSS recorded in June and July could be attributed to washouts from bare embankment of the TSF during the rainy season as observed during the sampling regime. Slurry discharge into the TSF could also contribute to the high TSS reported in TSF-DW. Mean TSS (10.03 mg/l) for groundwater was within GHEPA guideline and less than baseline mean (11.2 mg/l). Although, all the other surface water bodies recorded mean TSS within GHEPA limits, PWSD recorded extremely high TSS value of 990 mg/l, which was far above GHEPA maximum permissive limit (50 mg/l). The PWSD sampling sites is located uphill of the TSF and a receptor to effluents from illegal mining sites on ARL’s concession. High TSS in PWSD could possibly be as a result of effluent discharge from the illegal mining sites located uphill. Water bodies with high TSS could habor pathogens that may be harmful to humans and therefore not suitable for drinking (Noble et al., 2004). High TSS could also reduce the rate of photosynthesis in aquatic environment. 5.2 Chemical Parameters 5.2.1 Cyanide Cyanide is a toxic substance that renders tissues incapable of oxygen exchange (Shifrin et al., 1996). Significant concentrations of cyanide (Total, Free and WAD) was recorded in the Tailings decant water during the study. Free cyanide exceeded GHEPA guideline for effluent discharge. Elevated concentrations of cyanide in water could be hazardous to man and wildlife, particularly migrating bats and waterfowls (Eisler et al., 1999). Cyanide contamination of the decant water could be attributed to its use as University of Ghana http://ugspace.ug.edu.gh 86 a process chemical by Adamus Resources Limited as recounted by Acheampong et al. (2013) at Bogoso mine. High free cyanide concentration relative to other species (Total, and WAD) could possibly be attributed to excessive use of cyanide at the process plant relative to the rate at which they are broken down by natural process. However, Cyanide concentrations recorded in both surface and groundwater around the TSF were below detection limit in the entire study. Significant concentration of cyanide in the TSF with non-detection in water bodies around the facility suggests that cyanide in the TSF has not impacted on catchment water resources. This could possibly be attributed to adherence to the industry’s best practices as observed at ARL during the study. 5.2.2 Arsenic, Cadmium, and Mercury Arsenic (As) is an identified carcinogen, mutagen, and teratogen and it is associated with increasing risk of bladder, kidney, liver and lung tumors (Kortatsi et al., 2008). Chronic and acute poisoning by arsenic due to exposure to elevated concentrations is a common occurrence. Mean As concentration (1.26 mg/l) was above GHEPA maximum permissible limit of 0.1 mg/l recorded in TSF-DW. High As concentration in TSF-DW could be attributed to leaching of the element by cyanide from arsenopyrite ore mined by Adamus Resources Limited (Armah et al., 2010). Welch et al. (1988) reported that, As is an important auxiliary contaminant in mine waters, particularly where the ore bodies contain arsenopyrite as is the case at ARL. Even though, very high concentration of arsenic above GHEPA guideline for effluent discharge was recorded in the TSF decant water, arsenic concentrations in all surface University of Ghana http://ugspace.ug.edu.gh 87 water were within WHO (2011) guideline (0.01mg/l), except PWSD which recorded high As concentration of 0.021mg/l which was above the guideline and baseline mean of 0.003 mg/l. On the contrary, all groundwater recorded very low As concentration (mean concentration of 0.0014 mg/l) below WHO’s 0.1 mg/l and baseline mean 0.0071 mg/l. Low As concentration in groundwater although TSF recorded high concentrations could be attributed to arsenic’s ability to bind strongly to soil and therefore does not travel downward toward aquifers very quickly (Woo & Choi, 2001). Low As in groundwater could also be attributed to effective liner application systems of ARL’s TSF as suggested by Vick (1990). Findings from the study suggest that TSF has no impact on surrounding water bodies with respect to arsenic contamination. The spike in As concentration seen at PWSD is an isolated case and may be due to influx of effluents from uphill illegal mining sites during the rainy season. Cadmium and Mercury are important factors in aquatic monitoring studies. This is because, they have been found to be toxic to fish and other aquatic organisms (Essumang et al., 2007). Even though significant concentration of dissolved mercury and cadmium (below GHEPA limit for effluent discharge) was reported in the TSF-DW, the concentrations of these metals in surface and groundwater around the TSF were all below the detection limit. The results suggest that concentration of dissolved mercury and cadmium in the TSF-DW has not affected the quality of water within the vicinity of the facility. High levels of copper are associated with nausea, abdominal pain, or vomiting in humans (Pizarro et al., 1999). Mean dissolved copper concentration of 0.15mg/l below GHEPA effluent discharge (5 mg/l) was recorded in the TSF-DW. Concentrations of University of Ghana http://ugspace.ug.edu.gh 88 dissolved copper in groundwater (0.0015 mg/l) were greater than that of surface water (0.0020 mg/l). Copper concentration in both surface and groundwater were consistent with their respective baseline means (0.0017 mg/l and 0.002 mg/l respectively) and within WHO (2011) guideline (2.0 mg/l) for potable water. Results of the study suggest that TSF decant water has no impact on catchment water bodies with respect to copper contamination. 5.3 Correlation between Parameters A strong positive correlation was established between TSF-DW EC and cadmium (EC/Cd-D, r=0.674). Similarly, TSF-DW EC had a strong positive correlation with copper (EC/Cu, r=0.72). There was also a moderate positive correlation between TSF- DW EC, arsenic and free cyanide (EC/As, r = 0.499, EC/CN-F, r = 0.58). Electrical conductivity therefore increases with increasing cadmium, copper, arsenic and free cyanide and vice versa as per results obtained from the study. This suggests that free ions of Cd, Cu, CN-f and As account for the high EC recorded in TSF- DW and these elements originate from a single source - the ore and reagents used in the ore processing. Arsenic in TSF-DW had a very strong positive correlation with cyanide total, free and WAD (As/CN-T, r = 0.855, As/CN-F, r = 0.85, As/CN-WAD, r = 0.934). This implies that As concentration in TSF-DW increases with increasing cyanide and vice versa. Copper in TSF-DW also had a strong positive correlation with cyanide total, free and WAD (Cu/CN-T, r=0.63, Cu/CN-F, r=0.958). This implies that, concentration of copper University of Ghana http://ugspace.ug.edu.gh 89 increases with increasing cyanide and vice versa. The relationships between cyanide and metals in the TSF suggest that the higher the concentrations of cyanide in the TSF- DW, the more these metals are leached. No positive relationships between cyanide and any of the metals studied could be established from by Pearson’s Product Moment Correlation test conducted for both surface and groundwater around the TSF. This revelation suggests that there has not been any significant migration of cyanide and heavy metals (Arsenic, cadmium and mercury) from the TSF into surrounding surface and groundwater. The only significant relationship between parameters in surface water around the TSF is between TDS and copper (TDS/Cu, r = 0.881). This relationship suggests that copper in surface water possibly originating from surface bedrock contributes to TSD levels in surface water. 5.4 Social Survey Results of the survey indicate that inhabitants around the TSF believe the TSF has impacted on the quality of water in their vicinity. Five percent (5%) of the respondents related the impact to smell, 78% to colour and 17% to odour. It is also evident from the responses of the respondents that majority of respondents (65%) who live close to the TSF are not aware of the possible environmental impacts of the facility on their water resource. This suggests that the mine has not done enough to educate people in close proximity to the TSF about possible environmental impact of the facility. Majority of the respondents (78%) were of the view that turbidity of their water sources, especially, streams during the rainy season is due to seepage of chemicals University of Ghana http://ugspace.ug.edu.gh 90 from the TSF. This view was, however, not substantiated by the findings of the study. Study data and observations made during the sampling regime suggest that the streams‟ with high turbidity is probably as a result of run-off laden with silt from surrounding exposed areas and illegal mining sites on ARL’s concession. The mine has not done enough to educate folks living close to the facility about the probable impact of the facility on their environment as 83% of respondents indicated they have never been sensitized by the mine about such impact through any media. University of Ghana http://ugspace.ug.edu.gh 91 CHAPTER SIX CONCLUSION AND RECOMMENDATION 6.1 Conclusion Concentrations of key Ghana Environmental Protection Agency (GHEPA) conventional pollutants in ARL’S TSF decant water was above the agency’s guideline limit for the mining sector. However, the concentration of Ghana Environmental Protection Agency (GHEPA) conventional pollutants in surface water and groundwater monitoring boreholes within 500 m radius of the tailings dam were generally within acceptable GHEPA, Ghana Water Company, and World Health Organisation (WHO) guidelines. Concentration of pollutants recorded for surface and groundwater monitoring bore were also consistent with baseline data from the mine. The TSF of ARL therefore has no significant deleterious impact on the quality of surface and groundwater within its vicinity. Inhabitants around the TSF were of the view that, the facility has adversely affected the quality of their surface and groundwater sources with smell, colour and odour being the parameters significantly affected. 6.2 Recommendation  Investigation should be conducted to ascertain the reason for the high arsenic, TSS and TDS levels in Pond besides Water Storage Dam (PWSD).  Investigation should be conducted into the quantity of cyanide used in processing of ore and the rate at which they are degraded by natural processes in the TSF to ascertain whether or not the chemical is being over used. University of Ghana http://ugspace.ug.edu.gh 92  Bare areas around the tailings dam should be covered with vegetation (grassed or seeded with leguminous cover crops such as Pueraria phaseoloides). This crop will facilitate vegetative cover and mitigate erosion.  The mine should halt all illegal mining activities on its concession  The mine should conduct regular sensitization programs to reassure inhabitants in close proximity to the mine that the TSF has not impacted negatively on their water quality. The inhabitants should also be educated about the early signs of possible environmental impacts of the TSF on their environment.  The tailings decant water should be treated to meet GHEPA guideline for effluent discharge before discharging into the open environment. University of Ghana http://ugspace.ug.edu.gh 93 REFERENCES Acheampong, M. A., Adiyiah, J., & Ansa, E. D. O. (2013). Physico-chemical characteristics of a gold mining tailings dam wastewater. Journal of Environmental Science and Engineering, 2, 469-475. Ahmad, K., & Carboo, D. (2000). Speciation of As (III) and As (V) in some Ghanaian gold tailings by a simple distillation method. 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University of Ghana http://ugspace.ug.edu.gh 109 APPENDICES APPENDIX 1A: Physico-chemical Parameters of Tailings Decant Water (June- December, 2014) Parameter Range Mean SD GHEPA Guideline for Effluent Discharge WHO Guideline for Potable Water (2011) TSS (mg/l) 19 -105 55.29 31.29 50 NG pH 7.4 - 8.9 8.21 0.64 6 to 9 6.6 to 8.5 EC (µs/cm) 1340 - 1630 1507.14 113.39 1500 750 TDS (mg/l) 861 - 1040 964.57 70.42 1000 500 Color (TCU) <3 - 41 9.40 14.00 150 NG BOD (mg/l) ND ND ND 50 NG AS-D 0.17-5 1.26 1.68 0.1 0.01 Cd-D 0.0001- 0.0004 0.0002 0.00 0.1 0.003 Cu-D 0.058-0.35 0.1474 0.11 5 2.0 Hg-D 0-0.0002 8.57143E- 05 0.00 0.006 0.001 Total Cyanide 0.031 1.55 0.5868 0.52 1 NG WAD Cyanide <0.005 - 1.04 0.3427 0.47 0.6 NG Free Cyanide <0.005 - 1.04 0.3818 0.47 0.2 NG NB: ND= Non- detection, SD= Standard Deviation, NG= No Guideline Available University of Ghana http://ugspace.ug.edu.gh 110 APPENDIX IB: pH of Groundwater Monitoring Boreholes Monitoring bore Mean SD Range P-value TSFMBB02A 6.13 0.18 5.8-6.3 4.79399E-26 TSFMB02B 6.34 0.16 6-6.5 TSFMB03A 7.05 0.22 6.7-7.3 TSFMB03B 7.64 0.15 7.5-7.9 TSFMB04A 6.00 0.00 6.0 TSFMB04B 6.03 0.05 6-6.1 TSFMBO5 7.16 0.17 6.9-7.3 TSFMBO6 6.83 0.12 6.7-7 TSFMBO7 6.91 0.45 6.2-7.4 TSFMB08A 6.44 0.40 6-7.1 TSFMB08B 6.46 0.30 6.1-6.9 NB: SD= Standard Deviation APPENDIX IC: Electrical Conductivity of Groundwater Monitoring borehole samples NB: SD= Standard Deviation Monitoring bore Mean SD Range P-value TSFMBB02A 129.43 13.44 108-152 2.347E-35 TSFMB02B 190.85 23.84 168-237 TSFMB03A 441.85 89.74 277-557 TSFMB03B 373.71 6.32 366-385 TSFMB04A 114.71 5.42 106-120 TSFMB04B 128.14 24.08 110-173 TSFMBO5 362.71 75.59 179-405 TSFMBO6 190.85 13.07 179-210 TSFMBO7 208.56 5.07 201-215 TSFMB08A 134.00 3.16 129-139 TSFMB08B 187.00 13.18 165-207 University of Ghana http://ugspace.ug.edu.gh 111 APPENDIX ID: Total Dissolved Solids of Groundwater Monitoring Boreholes Monitoring bore Mean SD Range P-value TSFMB02A 84.29 9.45 70-99 4.83158E-35 TSFMB02B 124.00 16.83 109-154 TSFMB03A 285.86 61.44 180-357 TSFMB03B 242.29 5.50 233-250 TSFMB04A 74.57 3.82 69-78 TSFMB04B 82.86 17.26 70-113 TSFMBO5 252.71 9.89 236-263 TSFMBO6 124.29 9.14 116-137 TSFMBO7 135.71 3.64 131-140 TSFMB08A 87.14 2.12 84-90 TSFMB08B 121.43 9.40 107-135 NB: SD= Standard Deviation APPENDIX IE: Total Suspended Solids of Groundwater Monitoring Boreholes Monitoring bore Mean SD Range P-value TSFMBB02A 10.57 19.04 <1-53 0.0062 TSFMB02B 8.29 4.57 2-14 TSFMB03A 5.43 3.69 1-12 TSFMB03B 4.43 1.90 2-7 TSFMB04A 8.43 7.21 1-19 TSFMB04B 23.86 37.75 <1-102 TSFMBO5 29.57 16.59 <1-53 TSFMBO6 7.57 7.98 <1-18 TSFMBO7 4.71 5.56 <1-16 TSFMB08A 2.29 2.81 <1-8 TSFMB08B 5.00 0.79 <1-2 NB: SD= Standard Deviation University of Ghana http://ugspace.ug.edu.gh 112 APPENDIX IF: Dissolved Arsenic Concentration in Groundwater Monitoring Boreholes Monitoring bore Mean SD Range P-value TSFMB2A 0.000567 0.000115 0.0005-0.0007 0.107592483 TSFMB2B 0.0009 0.000141 0.0008-0.001 TSFMB3A 0.00254 0.004007 0.0005-0.0097 TSFMB3B 0.006333 0.003997 0.0021-0.013 TSFMB4A 0.0005 NA 0.0005-0.0005 TSFMB4B 0.00055 7.07E-05 0.0005-0.0006 TSFMBO5 0.0008 0.000415 <0.00010-0.0012 TSFMBO6 0.00126 0.000673 0.0001-0.0018 TSFMBO7 0.0006 0 0.0006-0.0006 TSFMB8A 0.000875 0.000556 0.0005-0.0017 TSFMB8B 0.000633 0.000153 0.0005-0.0008 NB: SD= Standard Deviation APPENDIX IG: Dissolved Copper Concentration in Groundwater Monitoring Boreholes Monitoring bore Mean SD Range P-value TSFMB2A 0.001 NA <0.0001-0.001 0.146685041 TSFMB2B 0.001 0 <0.0001-0.001 TSFMB3A 0.002 0.001 0.001-0.003 TSFMB3B 0.001857 0.00069 0.001-0.003 TSFMB4A 0.002667 0.001155 0.002-0.004 TSFMB4B 0.00165 0.001909 0.0003-0.003 TSFMBO5 0.0015 0.000707 0.001-0.002 TSFMBO6 0.001 0 0.001 TSFMBO7 <0.001 NA <0.0001 TSFMB8A <0.001 0 <0.0001-0.002 TSFMB8B 0.001 0 <0.0001-0.001 NB: SD= Standard Deviation University of Ghana http://ugspace.ug.edu.gh 113 APPENDIX IIA: pH of Surface water around the TSF Surface water Mean SD Range P-value BAN-T 6.53 0.14 6.3 - 6.7 0.001708172 ANG 6.30 0.19 6 - 6.5 TSFNWS 6.50 0.09 6.35 - 6.65 WSD 7.29 0.75 6.5 - 8.7 PWSD 6.75 0.52 6.1 - 7.29 NB: SD= Standard Deviation APPENDIX IIB: Conductivity of Surface water around the TSF Surface water Mean SD Range P-value BAN-T 185.71 144.16 109 - 510 0.001175857 ANG 67.00 10.83 47 - 76 TSFNWS 176.71 9.53 162 - 189 WSD 99.14 11.33 91 - 123 PWSD 55.54 26.57 32.2 - 88.3 NB: SD= Standard Deviation APPENDIX IIC: Total Dissolved Solids of Surface water around the TSF Surface water Mean SD Range P-value BAN-T 78.29 19.42 48 -103 0.007585543 ANG 43.43 7.16 30 - 49 TSFNWS 103.07 32.78 29.5 -123 WSD 64.43 7.44 59 - 80 PWSD 990.00 1177.82 11 - 3370 NB: SD= Standard Deviation University of Ghana http://ugspace.ug.edu.gh 114 APPENDIX IID: True Colour of Surface water around the TSF Surface water Mean SD Range P-value BAN-T 1.429 2.440 <3-5 0.1154 ANG 13.429 18.946 <3-54 TSFNWS 2.571 3.259 <3-7 WSD 3.000 4.243 <3-11 PWSD 3.286 4.645 <3-12 NB: SD= Standard Deviation APPENDIX IIE: TSS of Surface water around the TSF Surface water Mean SD Range P-value BAN-T 10.71 6.87 3-24 0.005791664 ANG 108.86 164.57 4-448 TSFNWS 24.14 7.73 18-38 WSD 21.00 14.32 3-37 PWSD 990.00 1177.82 11-3370 NB: SD= Standard Deviation APPENDIX IIE: Dissolved Arsenic Levels of Surface water around the TSF Surface water Mean SD Range P-value BAN-T 0.00104 0.000181659 0.0008-0.0012 0.017920232 ANG 0.00901429 0.004251442 0.0017-0.014 TSFNWS 0.001 NA 0.001-0.001 WSD 0.00355714 0.004199943 0.0011-0.013 PWSD 0.02128333 0.019210457 0.003-0.045 NB: SD= Standard Deviation University of Ghana http://ugspace.ug.edu.gh 115 APPENDIX IIF: Baseline Mean of Surface and Groundwater NB: GW= Groundwater, SW= Surface water BASELINE MEAN pH EC (µS/ cm) TDS (mg/l) TSS (mg/l) BOD (mg/l) Col. (TCU) As (mg/l) Cu (mg/l) CN- WAD (mg/l) CN-f (mg/l) CN-t (mg/l) Cd (mg/l) Hg (mg/l) GW 6.8 312. 0 218.6 11.2 <5 <5 0.005 0.0024 <0.01 <0.01 <0.01 <0.01 <0.01 SW 6.6 203. 8 36.6 22.0 <5 5 0.003 0.0026 <0.01 <0.01 <0.01 <0.01 <0.01 University of Ghana http://ugspace.ug.edu.gh 116 APPENDIX IIIA: Pearson’s Product Moment Correlation between Parameters Analyzed in the TSF RED=Significant Correlation, NR=No Established Relationship Colour (TCU) EC (µs/cm) pH TDS(mg/I) TSS(mg/I) As-D mg/l Cd-D (mg/l) Cu-D(mg/l) CN-T ( mg/l) CN-F(mg/l) CN-WAD(mg/l) Hg-D( mg/l) Colour (TCU) 1 EC (µs/cm) 0.294956344 1 pH 0.420989673 0.580416816 1 TDS(mg/I) 0.31901237 0.999596535148742**0.593463126 1 TSS(mg/I) -0.466428821 -0.282076979 -0.058371166 -0.29638023 1 As-D mg/l -0.105150416 0.499112053 0.021833318 0.485835995 0.484113809 1 Cd-D (mg/l) -0.058404965 0.67446824 0.371305329 0.669252883 -0.297720225 0.046364152 1 Cu-D(mg/l) 0.02820054 0.724199838 0.245545632 0.713875518 0.302884413 0.869753834 0.486569586 1 CN-T ( mg/l) 0.173896045 0.447964118 -0.101124583 0.443277962 0.110366707 0.855803744 -0.187608735 0.632472645 1 CN-F(mg/l) -0.236985306 0.585111147 0.094179997 0.56825964 0.449166411 0.850357061 0.492871173 0.958593748 0.52304438 1 CN-WAD(mg/l) -0.18895113 0.285836964 -0.319601342 0.269440039 0.460039481 0.934780109 -0.107784126 0.729405878 0.85771618 0.7523006 1 Hg-D( mg/l) 0.393240824 -0.141421356 0.5625 -0.122709136 -0.018507931 -0.301021062 -0.495073771 -0.454299411 -0.1407465 -0.5871781 -0.459235264 1 University of Ghana http://ugspace.ug.edu.gh 117 APPENDIX IIIB: Pearson’s Product Moment Correlation between Parameters Analyzed in Groundwater around the TSF RED=Significant Correlation, NR=No Established Relationship Colour (TCU) EC (µs/cm) pH TDS(mg/I) TSS(mg/I)As-D mg/l Cd-D (mg/l) Cu-D(mg/l) CN-T ( mg/l) CN-F(mg/l) CN-WAD(mg/l) Hg-D( mg/l) Colour (TCU) 1 EC (µs/cm) NR 1 pH NR -0.326835407 1 TDS(mg/I) NR 0.800411761 -0.67712895 1 TSS(mg/I) NR -0.35984769 -0.406743894 0.245079415 1 As-D mg/l NR -0.218870108 -0.187184192 -0.097366941 0.274535635 1 Cd-D (mg/l) NR 0.264924337 -0.723711055 0.777705685 0.790527901 0.082312 1 Cu-D(mg/l) NR 0.294796757 -0.699117613 0.645719031 0.46544283 0.505545 0.681782999 1 CN-T ( mg/l) NR NR NR NR NR NR NR NR 1 CN-F(mg/l) NR NR NR NR NR NR NR NR NR 1 CN-WAD(mg/l) NR NR NR NR NR NR NR NR NR NR 1 Hg-D( mg/l) NR NR NR NR NR NR NR NR NR NR NR 1 University of Ghana http://ugspace.ug.edu.gh 118 APPENDIX IIIC: Pearson’s Product Moment Correlation between Parameters Analyzed in Surface water around the TSF RED=Significant Correlation, NR=No Established Relationship Colour (TCU) EC (µs/cm) pH TDS(mg/I) TSS(mg/I)As-D mg/l Cd-D (mg/l) Cu-D(mg/l) CN-T ( mg/l) CN-F(mg/l) CN-WAD(mg/l) Hg-D( mg/l) Colour (TCU) 1 EC (µs/cm) 0.220481 1 pH 0.130198 -0.315455099 1 TDS(mg/I) -0.30634 0.007393158 -0.145030092 1 TSS(mg/I) -0.36722 0.358360729 0.014011621 0.849372 1 As-D mg/l -0.6539 -0.443416829 -0.430898348 0.466533 0.155703 1 Cd-D (mg/l) NR NR NR NR NR NR 1 Cu-D(mg/l) -0.34469 0.278650617 -0.169704958 0.881353 0.846698 0.361274808 NR 1 CN-T ( mg/l) NR NR NR NR NR NR NR NR 1 CN-F(mg/l) NR NR NR NR NR NR NR NR NR 1 CN-WAD(mg/l) NR NR NR NR NR NR NR NR NR NR 1 Hg-D( mg/l) NR NR NR NR NR NR NR NR NR NR NR 1 University of Ghana http://ugspace.ug.edu.gh 119 APPENDIX IIID: In-situ Water Quality Measurement University of Ghana http://ugspace.ug.edu.gh 120 APPENDIX IIIE: Interviewing of some respondents at their hamlets at Angajale during the Social Survey on 20th January, 2015. University of Ghana http://ugspace.ug.edu.gh 121 APPENDIX IIIF: QUESTIONNAIRE UNIVERSITY OF GHANA My name is Elvis Akwasi Acheampong. I am a student from University of Ghana, Legon pursuing a master of philosophy degree (MPhil) in Environmental Science. This questionnaire is part of the requirement to obtain my degree in the above mentioned program. My Thesis topic is “Assessing the impact of an operating Tailings Storage Sacility on catchment surface and groundwater quality: A case study of Adamus Resources Limited (Nzema Gold Mine) in the Ellembele district of the Western Region of Ghana” The main objective of the study is to ascertain the impacts of an operating Tailings Storage Facility on catchment surface and groundwater quality. I would therefore be grateful if you could spend a few minutes of your time to help me fill out the questionnaires. NB: All answers provided are strictly for academic purposes and would be treated as confidential Sampling Technique: Convenient sampling Target: Members of the local community living close to the Mine’s (ARL) Tailings Storage Facility including; fishermen and women, farmers, miners and artisans. Survey Date…………………… District…………………………. Name of Community………………………… Region……………………………….. University of Ghana http://ugspace.ug.edu.gh 122 A. PERSONAL INFORMATION 1. Sex: a. Male ( ) b. Female ( ) 2. Age: a. 20 -29 ( ) b. 30 -39 ( ) c. 40 - 49 ( ) d. 50 -59 ( ) c. above 60 ( ) 3. Occupation a. Farming ( ) b. Fishing ( ) c. Hand-work ( ) d. Small scale miner ( ) e. Trading ( ) f. Student ( ) g. Others: Specify……………….. 4. How long have you been staying here? a. 1-5yrs ( ) b.6-10yrs ( ) c.11-15yrs ( ) d.15-20yrs ( ) e. 20yrs and above ( ) f. less than a year ( ) 5. What is your residential status? a. Indigene ( ) b. Settler ( ) c. others ( ) 6. Educational Levels . No Formal Education ( ) b. Primary/JHS ( ) 7. c. Middle/SHS ( ) d. Tertiary ( ) B. INFORMATION ON SOURCES AND USES OF WATER 8. What are your main sources of water? 9. Which of these water sources do you often access? 10. What do you use the water for? (Can tick more than one) a. Domestic ( ) b. Irrigation ( ) c. Swimming ( ) d. Transportation ( ) e. Nothing ( ) f. Others ( ) 11. If others please specify……………………….. University of Ghana http://ugspace.ug.edu.gh 123 12 Do you subject the water to any form of treatment before use? Yes or No 13 If yes what kind of treatment do you use...? C. INFORMATION ON IMPACT ON TAILINGS STORAGE FACILITY ON WATER QUALITY 14. Did you live here before construction and operation of the Tailings Storage Facility by the mine? a. YES ( ) b. NO ( ) 15. Has operation of the mine’s Tailings Storage Facility affected your water quality in anyway? color, taste, smell etc Yes or No 16. If yes Please specify………………………………………… 18. Is the change in water quality permanent or occasional? Permanent or Occasional 19. Which time of the year do you see this change in water quality if change is occasional……. 20. Do you think the Tailings Storage Facility can impact on the quality of water sources available in your vicinity? a. YES ( ) b. NO ( ) 21. if yes , what kind of impact could it be? ……………………………………………… University of Ghana http://ugspace.ug.edu.gh 124 D. COMMUNITY AWARENESS OF THE POTENTIAL IMPACT OF THE TAILINGS STORAGE FACILITY 22. Have you ever been sensitized by the mine on the potential impact of the Tailings Storage Facility? a. YES ( ) b. NO ( ) 23. Do you have any more comments?............................................................. University of Ghana http://ugspace.ug.edu.gh