Artisanal small scale gold mining (ASGM) challenges corporate miners environmental performances: A case study from Ahafo, Ghana.

Transcription

1 Artisanal small scale gold mining (ASGM) challenges corporate miners environmental performances: A case study from Ahafo, Ghana. Fatien K.F. Macdonald, Mark Lund, Clint McCullough MAusIMM CP(Env)* Mine Water and Environment Research Centre School of Natural Sciences, Edith Cowan University, Perth, Western Australia *Golder Associates Pty, Ltd, Perth, Western Australia 1

2 Artisanal Small scale Gold Mining (ASGM): Why it matters 1/3 of world gold production (AGC) In 70 developing nations (UNEP 2013) Help eradicate rural poverty But Poor environmental, health and safety conditions World second largest Hg emitter (UNEP 2013) Proximity to corporate mines Commonly practised near to river, streams, lake 2

3 ASGM world distribution and mercury released from ASGM (t/y) UN data on 3

4 Ghana Gold Export 2013 * Goldfields Tarkwa 15% Newmont 13% Anglogold 6% ASGM 34% 34% *Ghana Extractive Industries Transparency Initiative (GHEITI) Report 4

5 ASGM (Galamsey) 101 Ghana 400 years old industry Legal or Illegal, but mostly illegal Legal provision for ASGM in Ghana (limited to Ghanaian nationals, some licensing procedure, selling and buying of gold and Hg through the Precious Minerals Marketing Company) Informal, Transient Low Tech Lack of long term planning 5

6 ASGM Process Pre concentrate amalgamation Whole ore amalgamation Hg 6

7 7

8 ASGM and aquatic ecology Mercury (Hg) and human health have been the main concerns BUT. Hg is not the only negative impact Other aquatic impacts (e.g. sedimentation, changes in river morphology & general water quality) often overlooked significant potentially easier to detect, monitor and manage 8

9 Impacts: Local areas 9

10 Changes in river flow Dry Seasons: Water abstraction Wet Seasons: Unregulated discharge of untreated mine water Elevated EC and Sulphate 18/08/

11 Impacts on landscapes and catchment areas Abandoned mines 11

12 2013 Sedimentation and river morphology changes

13 River Ecological Impacts of ASGM 13

14 The study Two rivers in Brong Ahafo, Ghana: Surow River (ASGM) ~ this presentation Subri River (Conventional Large Gold Mining) Water quality, sediment, riparian quality, Hg biomagnification in fish; macro invertebrates & microbial communities 18/08/

15 Study Area and Sampling Sites Ghana Study area Stream / River Swamp N o r t h Tano Basin Sampling Site ASGM Processors ASGM Mine & Processing Site Surow River Kenyase Kenyase Hwidiem T a n o R i v e r 7 15

16 Study Area N8 Amoma River Tano River Bosumkese Forest Reserve Awonsu River NSW9 KSW16 NGGL Ahafo Operation s Operation KSW3 NSW8 Tano River Stream /River Road (main) Road / path (secondary) Subri River Sampling sites Surow River Sampling sites Swamps AGSM mines and processing sites Township Surow River KSW13 Subri River Kenyase Subri River NSW6 Kenyase Surow River KSW Hwidiem Tano River 16

17 Ahafo Mines and Study Timeline Time / Event Ahafo Mine ASGM < Exploratio n/eia / Planning Constructi on Mill Began Feb Mar April May April Major ASG mining halted Small processors remain Study Fieldwork Began End 17

18 Summary of Results ASGM significantly impacted river sediment and water: Metal pollution of sediment and water at impacted sites Sr, Hg, Ca, Co, Mn, Mg, Zn, Cu Below standards and guidelines criteria for aquatic life & GWC guidelines / drinking water Sediment: Cr, Cu, Hg, Pb, Ni, Zn Water: Al, Fe, Hg, Mn The impact is temporal: rainy season is worse 18

19 Before/After x Control/Impacts Impact was significantly less after cessation of larger ASGM Some downstream impacts persisted PC2 5 0 Surow Sediment Metals PCA February 2013 and April 2014 Location Upstream Between Downstream ASGM Distance PC1 19

20 ASGM Environmental Management : Challenges Lack of institutional and technical capacities agencies and miners Lack of understanding of issues on the ground Unknown quantity Social economic : poverty, unemployment, education 20

21 Implication corporate gold mining Integrity of environmental management measures Potential downstream medium / long term impacts: Sediment is a sink of pollutants Water human health Fish biomagnifications Cumulative impacts Mine Closure Perception is reality 21

22 Concluding remarks Impacts of ASGM on riverine environment is significant, varied longitudinally and temporally Trace metal contamination is not only by Hg Impacts can be reversed, pending scale of impact Know your neighbour. Corporate s awareness of the risks Environmental and Social Impact Assessments (ESIA) and Mine Closure Planning (MCP) Monitoring of ASGM waterways 22

23 Thankyou. Medase! Centre for Ecosystem Management (CEM), School of Natural Sciences, ECU Mr. Mumin Zakaria and Mr. Yakubu Ibrahim of Hwidiem, Ghana Nana Berima Twireku Ampem III, Chief of Ntrotroso Town, Brong Ahafo, Ghana Nana Osuodumgya Berima Apiedwaa Boafo II, Chief of Hwidiem Town, Brong Ahafo Region, Ghana Kenyasi I Galamsey Committee, Brong Ahafo, Ghana. 23

24 18/08/