MT MORGAN OPEN CUT PIT WATER QUALITY MODELLING stage 2 ● 8
1. BACKGROUND
Mount Morgan Mine was a copper, gold and silver mine in Queensland, Australia. The Mount Morgan Mine site is currently managed under the Queensland government’s Abandoned Mine Lands Program (AMLP). This historic copper, gold, and silver mine operated between 1882 and 1981. It is located near the township of Mount Morgan, approximately 38 km southwest of Rockhampton on the Central Queensland coast. The mine site is adjacent to the Dee River, which flows between the mine and the township of Mount Morgan, into the Don and Dawson Rivers and thence into the Fitzroy River. The Queensland Government accepted environmental liability for the site after closure and has managed the site since 1993. Figure 1-1 shows the various mine waste units, including the open cut pit (OCP) and sandstone gully. The open cut was excavated into the northern flank of the Mundic drainage. It has a surface area of approximately 34.5 Ha and maximum depth of approximately 200 m (relative to the current rim). The open cut was backfilled between 1982 and 1990 with 28 Mt of retreated tailings, the majority of which was removed from Sandstone Gully. After final closure in 1990, the partially backfilled open cut (and Sandstone Gully) were allowed to flood further by natural inflows (surface runoff and groundwater inflow) and by pumping acid rock drainage impacted seepage back into the open cut. The Department of Natural Resources and Mines has long-term, large-scale rehabilitation of the Mount Morgan Mine planned. Heritage Minerals Pty Ltd (Heritage Minerals) have been issued an EA (EPML00433013) to reprocess tailings at Mt Morgan. OCP currently contains around 27.5 Mt of tailings and showing acidic conditions. In the first year, Heritage Minerals aims to process around 2 Mt of tailings. Heritage Minerals will be using the water in the OCP for their re-processing process (Figure 1-2) and re-processed tailings (new tailings) will be discharged into the OCP at around pH10.
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Heritage Minerals
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