Water Research Commission 40 Year Celebration Conference 31 August – 1 September 2011; Emperor‟s Palace, Kempton Park, Johannesburg (South Africa) BLUE vs. TRUE GOLD Impacts of deep level gold mining on water resources in South Africa – insights from selected case studies Frank Winde NWU Potchefstroom Campus Mine Water Research Group Contents (1) Introduction (2) Au mining impacts on water resources: 3 x case studies (A) Dewatering of karst aquifers (B) Uranium pollution (C) Flooding of mine voids (AMD decant) (3) The future? Largest urban agglomeration in Africa: - triggered by Au rush 125 years ago, today: - 25% population SA - 50% of energy consumption in Africa - 70% GDP SA Ferreira Camp (1886) ~400 x diggers - 70 km from nearest major river: strongly negative water balance imports from Lesotho Johannesburg (2011) ~4 million residents 50 Total surface runoff ) 45 40 km³/a 35 Economically 30 exploitable run off 25 demand ( demand 20 15 total water water 10 5 0 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 125 years of Au production: >6 bn t of tailings covering ~400 km² Total since 1886: 42,000 t 1970: Peak of SA gold production (989 t) = 68% of world production 17m all gold ever poured: 127 000 t Au 17m 33%: SA worldwide more steel is poured in 1 hour …1700 1400 Au-prize [$/oz] 1300 ‚Sunset industry‘? SA: 35.000t Au still available 1200 15 kt accessible with current technology 20 kt ultra deep mining needed 1100 1000 900 800 700 600 price [US$/ ounce] [US$/ price - 500 Au 400 WDL 300 200 m 4300 > 100 0 2011 1900 1870 1880 1890 1910 1920 1930 1940 1950 2010 1850 1860 1960 1990 2000 1970 1980 1800 1810 1820 1830 1840 1. Background: Au-mining and dolomite Case study 1: Dewatering (FWR) GAUTENG FAR WEST RAND WEST RAND NORTH WEST PROVICE CENTRAL RAND JHB Case study 3: KLERKSDORP Flooding/ AMD (CR) Case study 2: EAST RAND U pollution (WFS) MPUMALANGA EVANDER FREE STATE FREE STATE 100 km (Draper report) Zuurbekom pumping station continuous pumping since 1899 EVANDER Goldfield Mine lease area Case study 1: Dewatering of karst aquifers (Far West Rand) Case study 1: Dewatering Dolomitic compartments highly karstified ~365 km² JHB Mooi River Mooi Ohz. c VP c - 5 x longest caves in SA Bank c - 2 x strongest ~800 km² springs - storage capacity dewatered GMB compartments > Vaal Dam ####### ## ## # # # # # # ### Boskop Dam # # ## Potchefstroom ### # Apocalypse cave ## # ### # # Case study 1: Dewatering of karst aquifers - consequences Case study 1: Dewatering - altering recharge rates Case study 1: Dewatering – tailings injection into karst aquifers Dolomitic outcrop area of Sinkhole dewatered compartments Wetland Slimes dam Stream Khutsong N Winde (2006) Case study 1: Rewatering – decant of AMD flooded mine voids 30 Ml/d active mine voids ~130 Ml/d GMB GMB as potential outflow point Total mine void volume FWR: est. 600 Mio. m³ (prior to deepening projects) Case study 2: Uranium contamination - Wonderfonteinspruit (2) Case study 2: U pollution - history DRD Rand Uranium poss. re-open GM Tailings 1st U-pilot plant 1949 Blyvooruitzicht GM First U-plant SA: WR Cons. 1952 JHB GFL Mintails Tailings + by-prod .+ U-plant Tailings WFS Mooi River NUFCOR GMB Dominion (240.000t) New U-mine Simmer & Jack N Potchefstroom Re-opened GM Chem Wes Tailings Buffelsfontein West Wits Re-opened GM Tailings + by-prod .+ U-plant Vaal River Vaal Reefs 10 x GM produce U for Tailings + by-prod .+ U-plant 5 x U-plants in FWR/ WR (2) Case study 2: U pollution- sources West Rand (mined out) Slimes dams in WFS catchment: Mass: ~1.5 bn t Surface area covered: ~50 km² U-contents: ~150,000 t of U slimes dams GMB Far West Rand (most mines still operational) (DWAF 2006) (Coetze 2003) (2) Case study 2: U pollution – media reports (2) Case study 2: U pollution - studies Selected studies (16 out of 35) 1967 – CoM/ DWAF – Onderstepoort study on health impacts (confidential) 1991 – Deelkraal GM – U-levels in urine of miners 1991 – Pulles (COMRO) – Health hazard of radionuclides in GM (confidential) 1992 – Slabbert (Dfnt. GM) – Radioactivity concentration in mine effluents 1996 – IWQS (DWAF) – Screening on water radioactivity in mining regions 1997 – IWQS (DWAF) - Radioactivity Monitoring in WFS 1998 … ongoing: DWA - Mooi Rivier radioactivity surveillance programme 2000 – Wade et al. (CSIR for WRC) – Radioactivity in sediments of the WFS 2000 - Nel (Potchefstroom municipality) – U-monitoring programme 2002 – CGS (for DWAF) – Radioactivity in sediments of AC Dam 2003 – Metago (for WRC) – U-pollution by filling sinkholes with tailings 2004 - Blyvooruitzicht Gold Mine U-monitoring programme 2004 – Coetzee, Winde, Wade (WRC 1214) - U-pollution risks 2005 – DWAF – U-contamination of mine canal sediments 2007 – NNR (Brenk report) - radioactive dose calculation WFS 2007 – Sediment analysis by GFL Ltd. (WAG) 2008-2011: 10 x more studies added 1 Site-nr. (Tab. 1a/b) G: 100 (1) Source (A...K): av U (n) max.U [µg/l] U-conc. stream water: 1997 - 2008 4 (C2H152) A: 156 (25) 406 Slimes dam B: 319 (19) 705 Rock dumps - 12 x studies/ monitoring programms 5 Mine lease boundary - ~3400 x U-conc. data for water C: 29 (69) 198 Outcrop of dolomite 6 (C2H153) A: 20 (25) 99 Dewatered dolomite B: 8 (22) 23 C: 13 (66) 78 36 8 A: 0,8 (29) 9,1 10 (Att. Dam) C: 17 (69) 543 C: 16 (64) 289 (23)76 B: 0,8 (2) 1,1 (17)100 (2) 69 J: 14 (1) 60 50 37 67 Harmony GM A: B: J: J: 3,0 (1) 22 16 Doornkop (2) 48 C: 62 (67) 759 sectrion (77) 124(77) (1) 46 18 (1m – out) 24 J: 44 37 A: 31 (31) 58 17 (1m – in) (31) 160(31) 106(55) (1) (1) B: 26 (21) 59 D: K: 26 A: 38 (25) 71 (C2H069) 57 85 79 J: 19 (1) 23 B: 44 (23) 76 K: 31 (1) 31 A: B: J: K: (305) 566(305) Harmony GM (3) 84 (4) 94 (4) Kloof GM Cooke (AC dam) (AC 71 65 (Venterspost) 55 sectrion 32 B: D: J: (31) 7,0 (31) 20 (20) (16) 43 (16) (C2H013) 0,9 1,6 14 34 A: E: B: (25) 104(25) 52 (22) (105) 172(105) Simmer & Jack U-mine 19 22 13 35 A: B: D: Driefontein Cons. GM South Deep GM 33 Doornfontein/ J: 105 (1) Blyvooruitzicht GM K: 99 (1) 39 Elandsrand A: 0,5 (31 2,1 B: 2,3 (16) 24 GM Deelkraal GM 40 (Boskop dam) A: 2,7 (31) 9,5 B: 11 (26) 142 N 43 (Potch dam) A: 4,2 (23) 48 10km B: 14 (12) 57 out of map Decanting mine 15 West Rand void water 6679 (2) Case study 2: U pollution - Wonderfonteinspruit 1219 793 8 319 Bovenste Oog +104% perennial perennial - 50 Mooi River Mooi 0,8 C2H152 non 993 1m pipe 1m Outflow Dam Don 15 Outflow C2H025 C2H172 +130% Harry„s dam Harry„s 0% Outflow 1607 80 871 34 15 C2H080 +286% Gauging Gauging station upstr. A Dam of Coetzee C2H080 100 159 C2H175 1358 C2H157 62 Klerkskraal +69% Cooke #1 dam C2H172 143 C2H154 effluent 175 C2H069 26 3196 50 C2H069 +38% 1099 292 20 C2H171 -32% 35 C2H063 +17 425 57 86 32 -66% Venterspost (Kloof) 25 GM C2H061 Driefontein GM Fissure water dirt road road culvets dirt C2H161 at Muiskraal WFS 13-fold increase 190 95 270 C2H160 C2H156 of U-load 1342 Mooi River Mooi - 33% +1260% - 40% Blyvooruitzicht GM -52% 40 18 C2H013 5 At Doornfnt # 3 shaft 35 13 14 Upper Turffontein 148 105 N Eye Not to scale 51 Gerhard 43 2,3 Minnebron Eye Receiving stream +330% C2H011C2H011 Discharge from active gold mines into the WFS 200 Dolomtic karst springs 11 C2H162 Inflowbridge Boskop dam 803 C2H069 DWAF code for sampling points +308% 3-fold increase C2H174 Boskop dam Ml/d average flow [Megalitre per day] of U-load ppb average U-conc. in water [µg/l] (italic- sources other than DWAF) 10 51 Potch dam 14 +240% 793 U-load [kg/a] (1998-2008) +104 To Potch water supply U-load difference [kg/a] (since 1997), (+ load increased; - load decreased) (Winde 2009) to Vaal River Case study 2: U-pollution ~3.5 t/a TFT eyes ? Mooi Rivier Mooi GMB eye Natural dissolution of dolomite results in abundance of: Boskop dam 2+ 2+ - Ca , Mg , HCO3 each ion found to reduce U- removal effiency of standard potabilization processes to 60% Potch (Baeza, 2008 water works ) i.e. In dolomitic water U standard is more likely to slip potabilization: chlorination, through treatment flocculation, plants filtration 2003: Kettle scale 21 vs 1 ppm Case study 2: U pollution – health effects - 1995: Dr de Villiers (Stellenbosch Univ.) high number of leukaemia patients from area around Poffadder (N-Cape) - blood samples of 418 people from 120 localities (>16 a of age, 1993) - water quality: 126 boreholes, AEC data (early 1980s) (2) Case study 2: Uranium pollution – health effects U-levels Lymphocythe count in 126 boreholes (418 residents from 120 localities) Reddish colours: Reddish colours: 30-100 % of sampled U: >70 – 300 µg/l population with abnormally high lymphocyte count WFS: >300 (upper) … 80 µg/l (lower) Mine water: 200 … >3000 µg/l 500 000 grid cells correllated r = 0,5731 3 x follow-up studies confirmed high U-levels and domestic use of water Case study 3 Flooding of mine voids (AMD) (2) Case study 3: Flooding of mine voids flooded mine voids 15 Ml/d active mine voids (2002) 60 Ml/d (2012) ~130 Ml/d (2050?) GMB Total mine void volume FWR: est.