Mount Morgan Mine Upper Mundic Gully TSF EA Amendment

Aspect

Potential Impact

Risk Rating

Risk Controls

Residual Risk Rating

Treatment

L

C

R

L

C

R

tailings properties are similar as they originate from the same processing plant. Rehab methodology well defined to achieve a safe, stable and non- polluting landform. The proposed activity will result in the reduction of contaminant sources via the excavation and placement of historical ARD generating mine waste into TSFs When tailings are appropriately managed in a TSF, the geochemical properties of the treated tailings are not expected to cause harm to the receiving environment TSF designed by RPEQ in accordance with DETSI guidelines

Adverse effects on the environmental values of and due to unplanned releases or discharges, including spills and leaks of contaminants

Potential impacts on land from construction and operation of the Upper Mundic Gully TSF are unlikely

Possible Moderate 13

Unlikely Moderate

9

given the significant existing disturbance within the area

associated with the Western Dump placement and construction of the water diversion tunnel. The construction of the Upper Mundic Gully TSF will likely improve impacts to land as the currently exposed face of the Western Dump will be sealed.

and ANCOLD best practice Annual regular maintenance

inspections in accordance with EA conditions in Schedule H and the Manual for Assessing Consequence

Categories and Hydraulic Performance of Structures (ESR/2016/1933) .

Nature conservation

Clearing of potential, but degraded, habitat for several MSES

Likely

Moderate 17

Pre-clearance fauna surveys will be undertaken by suitability qualified and experiences persons to identify individual fauna at direct risk from clearing

Likely

Insignificant 7

Considering the historical disturbance and degraded nature of the project area, including existing

ARD contamination in soil, the modified hydrology, and the presence of dense patches of

Project number: 25B061

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