MANAGEMENT OF THE MOUNT MORGAN MINE SITE, QUEENSLAND

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1 MANAGEMENT OF THE MOUNT MORGAN MINE SITE, QUEENSLAND December 2016 Derelict Mines Summit Singleton NSW Authors Oskar Kadletz and John Frankish

2 Site History Mining operations began in 1882 and ceased in November 1990 The State government subsequently took over management of the site. Tenders for existing mining leases 2003 an agreement was set in place between the state and the successful tenderer for the mining leases to facilitate reprocessing of the residual mineral resources Currently the government still manages the site, as active reprocessing has not yet been undertaken The ML holders Norton Goldfields Limited and their partners Carbine Resources Limited are in the final stages of a feasibility study. 2

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4 Long Term Strategies Continual reduction/de-water of Open Cut Pit via water treatment plant and evaporators; Reduce inflows into Open Cut Pit (Dam 8 & overland flow); Trials to investigate potential for relocating/capping of priority dumps (pending mining resource areas); Make safe works on site heritage aspects in line with site priorities and legislation; Facilitate reprocessing options for longer term site remediation; Continue to actively engage with the local community, via the sharing of information and having presence at a local level. 4

5 Current Site Management Priorities Safety and Health Pit Water Level Reduction Mining Leaseholder Partnerships Seepage Pumpback Systems Mundic Gully Emergency Action Plan Water Monitoring Upgrading of sites priority electrical infrastructure Fireclay Caverns tourism study Improvements to the Seepage interception System 5

6 Site Safety and Health Key Issues Ageing and deteriorating site infrastructure (electrical, heritage building structures, facilities, land forms) Acidic environmental conditions Activities on site: staff, external contractors, visitors, mining company staff and contractors

7 Mine Pit Water Level Reduction Current status of the Open Cut Pit 3.2 metres below spillway crest Lowest level since 2010 Able to contain approx. 1600mm steady rainfall

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9 Water Level Reduction Systems - Water Treatment Plant Lime based WTP was commissioned in 2007 Currently collaborating with the Mining Lease partners to improve WTP efficiency Improve resilience by removing dependence on local fresh water storage Plant Performance Water quality issues Gypsum and sludge management issues

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11 Evaporator System 3x 21 L/sec units operational since mid Operation subject to wind direction New intake system being installed due to the lower water level in the Mine Pit

12 Reducing Pit Inflows - No.8 Freshwater Dam Seepage

13 Reducing Pit Inflows - No.8 Freshwater Dam Seepage Massive level rises in large storms Pump Out via pontoon mounted diesel pump Second trailer mounted diesel pump for high water levels Pumps combined discharge capacity 100 L/sec After major storm event, water level can be returned to operating level within 7 days instead of the >30days in Set up on high bank, operation triggered by float switch, effective during Cyclone Marcia. Dam is currently virtually dry, and is required to provide water for the WTP

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15 Seepage pump back systems

16 System Overview 10 catch dams/sumps, multiple links with small pumps 4 major pumps returning water to the OCP

17 Pumpback Volumes Pumpback volume (ML) intercepted and returned to OCP 01/07/2015 to 13/12/2016 (18 months): Total = 1246 Mundic West = 758 Frog Hollow = 319 No. 2 Mill = 97 Shepherds Holding = 72 Rainfall Calendar year to date: mm Last financial year: mm

18 Mundic Gully Emergency Action Plan Strategy to protect lives in event of uncontrolled piping/failure of the Mundic Gully Embankment Embankment failure was assessed as low / unlikely by engineers in 2015 Reducing the water level in the OCP will further reduce risk

19 Contingency Plan - Communications Strategy for poor downstream water quality Strategy to alert downstream water users of acidic seepage flow or pit water release Notifications issued via and SMS to impacted stakeholders Notifications also sent when ph<6 recorded at Wura (20km downsteam)

20 Major Pumpback Systems Mundic Gully

21 No 2 Mill

22 Dee River Surface Water Monitoring Sampled every 2nd month Additional sampling triggered by events 7 key sites from the main crossing to 70km d/s Meyenberg, Kenbula, Walmul, Wura, Dululu, Deeford, Rannes Sampling includes total and dissolved metals General trends associated with flow events indicate an acid pulse followed by recovery period

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24 Questions?