Minmetals Resources Limited 2011 Sustainability Report (PDF)

ENVIRONMENTAL FLOWSSEEPAGE036REINJECTION 0DISCHARGE TO ESTUARY 973DISCHARGE TO SEA/OCEAN 0SUPPLY TO THIRD PARTY 988EVAPORATION 11146ENTRAINMENT 4709OTHER (DEFINE) 1262011 MMG water outputsWater management, treatment processes andinfrastructure are in place at all of our operational sites.We are working to effectively manage our output waterquality in line with local licence conditions. As the outputdata in the following chart shows, the majority of ourwater outputs, 16,806 megalitres, are to surface waterdischarge, with a significant water loss via evaporation atmost sites (11,146 ML in 2011).2011 MMG water output qualityWater output quality is monitored at all sites to meet ourlicence and reporting conditions. We present it here inline with the MCA WAF categories. As charted, around70% of our water outputs are classified as Category 2,with the remaining classified as Category 1 and the lowerquality Category 3.Century experienced a one-in-150-year rain event in2011, which resulted in a challenging year for watermanagement at the site. This included several incidentsSOUTHof sediment dam discharges, which HERCULES were reported to theenvironmental regulator in line with 690 our licence conditions.A Queensland Department of Environment and ResourceManagement 9,507 (DERM) investigationCENTURYfollowed. On 9 March28,6392012, MMG Century Limited received a summons toanswer the complaint that Century contravened aSEPON condition of its environmental authority (Section 430(3)10,088of the Environmental Protection Act 1994 (Queensland)).During the remainder of 2011, Century focused on2,523improving wastewater containment capacity, including theconstruction of a diversion channel around the operation’sevaporation dam to reduce the volume of surface waterentering the system on site during times of high rainfall.Golden Grove's water comes from the dewatering ofour two underground mines. This water is used for oreprocessing, and treated for dust suppression and dischargeto Lake Wownaminya. Potable water at Golden Grove issourced from bore fields and is treated through a reverseosmosis plant. A new reverse osmosis plant was installedduring 2011, greatly improving potable water quality.On average, 2011 was a slightly drier year for Rosebery,allowing the Rosebery environment team to focus onwater monitoring. Water treatment and monitoring werethe focus at the satellite South Hercules trial developmentsite, with a new modular and potentially relocatablewater treatment plant in operation.A total of 2,507 millimetres of rainfall was recorded atSepon, making 2011 the fourth wettest year on record.Rainfall has been measured and recorded at Sepon since1994, with only 2005 (2,679mm), 2002 (2,627mm) and1996 (2,621mm) having more rainfall than 2011. The newsediment dams in the western areas of the site performedwell during this initial year of operation. The project toprovide clean drinking water to villages surrounding Seponalso continued in 2011, with 12 villages and 3,400people now having access to clean water supplies.ROSEBERYGOLDEN GROVETOTAL OUTPUTS BY DESTINATION (ML)ENTRAINMENT4,709EVAPORATION11,146SUPPLY TOTHIRD PARTY988DISCHARGETO ESTUARY973WATER OUTPUTS BY SITE (ML)SOUTHHERCULES8ROSEBERY9,484SEPON8,106GOLDENGROVE2,415TOTAL OUTPUTS BY WATER QUALITY (ML)3,76023,7427,282OTHER126SURFACEWATERDISCHARGE16,806SEEPAGE36AVEBURY132CENTURY14,639Water QualityCategory 1Water QualityCategory 2Water QualityCategory 3Water quality key(Minerals Council of Australia Water Accounting Framework):Category 1 – Close to the drinking water standards, as it onlyrequires minimum treatment (disinfection) to be safe for humanconsumption. It can be used for all purposes.Category 2 – Suitable for some purposes. Treatment will berequired to remove total dissolved solids and/or to adjust otherparameters to be safe for human consumption and more sensitiveagricultural and recreational purposes.Category 3 – Water unsuitable for most purposes due to the highsalinity (>5000mg/L of total dissolved solids) or highly unsuitablepH (10). Category 3 water will require significanttreatment to be suitable for Category 1 and Category 2.54