Table 70. Risk Assessment Results
Aspect
Potential Impact
Risk Rating
Risk Controls
Residual Risk Rating
Treatment
L
C
R
L
C
R
Water
Release of tailings/ water from Upper Mundic Gully TSF causing impact to surface water receptors
Possible Moderate 13
TSF designed by RPEQ in accordance with DETSI guidelines and ANCOLD best practice. Given the total volume capacity of both assessed stages of the TSF, a flood included overtopping failure was deemed as non-credible. Failure mode analysis undertaken that indicates the OCP would buffer most of the receiving water in most release scenarios. The TSF size has been designed to accommodate a PMP storm event. 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) . Reduce potential for seepage from TSF into Dam 8 through construction of the 1.5 m concrete plug to be located in competent rock approximately 5 m past the tunnel inlet. TSF designed by RPEQ in accordance with DETSI guidelines and ANCOLD best practice
Unlikely Minor
5
None identified. The proposed amendments are unlikely to result in further impacts to surface water values in the Dee River and downstream riverine systems. Heritage Minerals will not be discharging water into the Dee River as part of mining operations.
Release of tailings/ water from Upper Mundic Gully TSF causing impact to
Installation of groundwater monitoring bores and ongoing monitoring through proposed conditions
Possible Moderate 13
Possible Minor
8
Project number: 25B061
Page 207
Powered by FlippingBook