The Brukunga Pyrite Mine: a Field Laboratory for Ard Studies
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THE BRUKUNGA PYRITE MINE: A FIELD LABORATORY FOR ARD STUDIES GrahamGraham FF TaylorTaylor RaymondRaymond CC CoxCox BRUKUNGA HISTORY G Mine opened 1955 G Pyrite (pyrrhotite) concentrated on-site G Transported to Port Adelaide for conversion to sulfuric acid G Minewastes disposed of on-site G Mine shut 1972 G Small township remains on site CSIRO Environm ental Projects Office BRUKUNGA GEOLOGY G Talisker Calc-siltstone of Cambrian Kanmantoo Group G Sulfide – rich bands in Nairne Pyrite Member over 100 km strike G Three steeply E-dipping conformable lenses G Each lens 15-30 m thick G Iron sulfides in muscovite schists/gneisses G Waste rock of quartz plagioclase granofels G Pyrite, pyrrhotite, minor sphalerite, chalcopyrite, galena, arsenopyrite CSIRO Environm ental Projects Office Brukunga Mine Site layout and Sampling locations CSIRO Environm ental Projects Office MINING LEGACY G Exposed quarry benches G Diversion of Dawesley Creek G Waste rock dumps G Tailings storage facility G Ponding on tailings surface CSIRO Environm ental Projects Office Quarry faces CSIRO Environm ental Projects Office Waste rock dumps CSIRO Environm ental Projects Office Wall of TSF and retention dams CSIRO Environm ental Projects Office Sludge dam CSIRO Environm ental Projects Office MINING LEGACY – cont. G Water contamination G Soil contamination G Cover materials G Noise, dust, odour G Municipal impact CSIRO Environm ental Projects Office Seepage From TSF CSIRO Environm ental Projects Office Contamination of Dawesley Creek CSIRO Environm ental Projects Office Representative Water Quality from Mine Sources (range of values shown) Parameter Dawesleys u/s Dawesley d/s Waste Dump (mg/L) except Mine Cuts Tailings pH Peggy Buxton (KAN 2) R/O and Seep* PH 2.5 2.3 7.5 3.0 2.5 3.0 4.5 3.0 Acidity# 4,000 7000 0 200 4,000 8,000 1,000 6,000 SO4 5,000 8000 80 1,000 6,000 10,000 100 2,000 9,000 Fe 1,000 4000 1.5 10 200 2,500 30 600 Al 400 50 <1 25 700 800 200 1,000 Cl 300 250 400 500 100 1,500 200 Ca 200 450 50 100 200 500 60 300 300 Mg 200 300 40 50 200 500 60 100 300 Na 200 200 450 300 100 1,200 400 Mn 20 150 0.1 5 30 40 20 50 Zn 30 15 0.005 15 20 CSIRO Environm ental50 Projects Office 50 BRUKUNGA - MONITORING Required by EPA Site Licence No. 10577 G Annual and seasonal lodes of heavy metals entering Dawesley Creek G Impact of mine on Dawesley Creek using biological monitoring every 3 months G Determine spatial and temporal variations of pH and heavy metal concentrations in zone of impact – monthly program CSIRO Environm ental Projects Office Note: Chromium, Copper and Lead were not graphed because a high number of Samples are recorded as being below the detection limits of the analysis technique. Using this data can result in high calculated loads that are not real. Continued ... CSIRO Environm ental Projects Office Calculated annual load of contaminants in Dawesley … continued CSIRO Environm ental Projects Office BRUKUNGA – WATER QUALITY G Sampled at 8 localities G Analysed for pH, TDS, conductivity 2- Cu, Fe, Pb, Mn, Al, Ni, Cd, Zn, Cr, SO4 G Ecosystem impact - macroinverterbrates CSIRO Environm ental Projects Office 2002 pH results against four year average Dawesley Creek as it leaves the Brukunga Mine site 7.0 6.0 Max imum 5.0 Lower limit ANZECC guideline for irrigation pH 4.5 4.0 Average pH 3.0 Minimum Winter 2.0 Summer 1.0 0.0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec CSIRO Environm ental Projects Office 2002 Sulphate results against four year average Dawesley Creek water as it leaves the Brukunga Mine site 10,000 9,000 Sum m er 8,000 Max imum 7,000 6,000 5,000 Average 4,000 Minimum 3,000 Concentration (mg/litre) Winter 2,000 1,000 1992 ANZECC recommended guidline for livestock 1,000 mg/litre 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec CSIRO Environm ental Projects Office 2002 Cadmium results against four year average Dawesley Creek water as it leaves the Brukunga Mine site 0.25 Summer 0.20 Maximum 0.15 Average 0.10 Winter 0.05 Concentration (mg/litre) Minimum 1992 ANZECC recommended guidline for livestock 0.01 mg/litre 0.00 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec CSIRO Environm ental Projects Office 2002 pH results against four year average Mt Barker water downstream of the Brukunga Mine site 12.0 10.0 Upper limit ANZECC guideline for irrigation pH 9.0 Summer 8.0 Max imum pH Winter Average 6.0 Lower limit ANZECC guideline for irrigation pH 4.5 Minimum 4.0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec CSIRO Environm ental Projects Office 2002 Sulphate results against four year average Mt Barker water downstream of the Brukunga Mine site 700 Max imum 600 Sum m er Winter 500 Average Minimum 400 300 200 Concentration mg/l 100 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec CSIRO Environm ental Projects Office 2002 Cadmium results against four year average Mt Barker water downstream of the Brukunga Mine site 0.02 0.01 Max imum 1992 ANZECC recommended guidline for livestock 0.01 mg/litre 0.01 0.01 0.01 Summer Winter Average 0.01 0.00 Concentration mg/l 0.00 Minimum 0.00 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec CSIRO Environm ental Projects Office Dawsley Creek system-mean & Standard deviation species riches six sites: 1996-2001 45 40 35 30 25 20 15 SPECIES RICHNESS 5 5 0 US Peggy Buxton D/S Brukunga U/S McIntyne Rd Balyrata Freeway Nairne Ck SITE CSIRO Environm ental Projects Office Species richness and pH CSIRO Environm ental Projects Office BRUKUNGA - MONITORING G Depth to water table in TSF G Ecology – algal activity benthic diatoms freshwater shrimp aquatic fungi microbial communities G Groundwater hydrology G Soils and stream sediments G Oxidation rates CSIRO Environm ental Projects Office BRUKUNGA – ENVIRONMENTAL MANAGEMENT G Water collection G Neutralisation plant G Rehabilitation of TSF G Rehabilitation of waste rock dumps G Rehabilitation of quarry faces CSIRO Environm ental Projects Office BRUKUNGA RESEARCH By ANSTO, CSIRO, AWT, AWQC and tertiary institutions G impact of biosoloids and neutralisation sludge G oxidation rates G development of ecological risk assessment protocol G Cd/Zn contamination in soils G aquatic ecosystems … cont. CSIRO Environm ental Projects Office BRUKUNGA RESEARCH - cont. By ANSTO, CSIRO, AWT, AWQC and tertiary institutions G microbiological reduction of AMD G hardpan / cement formation G porous reactive wall to remove contaminants G ecotoxicology G hyperspectral remote sensing CSIRO Environm ental Projects Office BRUKUNGA – ENVIRONMENTAL IMPROVEMENT PLAN G Diversion of Dawesley Creek G Additional lime treatment capacity G Relocation of rock dumps G Community consultation G BMSR Board – activities G Informal liaison G Aboriginal heritage CSIRO Environm ental Projects Office BRUKUNGA – MAINTENANCE COSTS Total = $650,000 (2001 – 02) G Salaries ($150,000) G EPA Licence ($12,900) G Monitoring program ($67,300) G Power ($25,200) G Lime and flocculant ($77,800) G Relocation of neutralisation sludge ($85,700) G Overall maintenance ($205,300) CSIRO Environm ental Projects Office BRUKUNGA – CONCLUSIONS G A legacy of poor practices G Contamination of Dawesley Creek G “Band-aid” treatment to date G Concerted effort by PIRSA to fix problems G Community consultation G Good example of attitude changes during last 20 - 30 years CSIRO Environm ental Projects Office ACKNOWLEDGEMENTS G PIRSA for permission to publish G Peter Grindley for continued insight G Members of the BMSR Board G All those who made data available CSIRO Environm ental Projects Office.