3.2. Alternatives to the Amendments
3.2.1. Amendment #1
Most land within the Mount Morgan Mine tenures are highly disturbed from historical mining and waste
disposal activities that has resulted in source contaminants remaining in-situ and caused significant
environmental harm to the receiving environment. There is a lack of suitable areas within the mining
tenure to construct a new TSF due the presence of historically placed waste material, relatively limited
undisturbed areas within the ML and diverse topography. A siting assessment was performed to inform
TSF design and though this it was determined that the Upper Mundic Gully area provided the most
favourable conditions to reduce long term stability risks, seal exposed historic waste rock dumps and
accommodate the dimensions of the proposed TSF.
An options assessment to determine potential locations for processed tailings disposal is provided in
Table 15 with the preferred option chosen to support this proposed amendment highlighted .
Table 15. Processed Tailings Disposal Options Assessment
Advantages
Option
Disadvantages
Avoids further disturbance at a significantly modified and contaminated site
Does not provide for a more resilient water management strategy that reduces loss of containment risks to ALARP ITE unlikely to support mine plan
•
•
Do nothing
•
Permanently stores processed tailings Majority or TSF footprint is a highly disturbed environment associated with previous mining activities Provides long term water management capacity that is future proofed against potential climate change impacts Favourable topography that provides for a valley TSF geometry that reduces stability risks Currently exposed waste rock dumps will be encapsulated by the TSF Upper Mundic Gully footprint is hydrogeological and topographically upgradient of existing environmental impacts at the Mount Morgan Mine Avoids sterilization of resources as treated tailings deposition will occur in an area with no known latent tailings resource recovery
• •
•
Unavoidable impacts to some MSES however management strategies are proposed to reduce impacts Requires an amendment to the EA
•
•
Discharge produced tailings into Upper Mundic Gully TSF
•
•
•
•
Permanently stores processed tailings
The maximum volume of tailings authorised for discharge into Sandstone Gully TSF is 11Mm 3 and this volume has been accounted for in the mine plan The proposed tailings discharge volume into Upper Mundic Gully TSF is 9.24Mm 3 which could not be contained within Sandstone Gully TSF Although the Sandstone Gully TSF was designed for a maximum of 6 Stages, the EA
•
•
Discharge additional produced tailings into Sandstone Gully TSF
•
•
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Wulguru Technical Services Pty Ltd – Supporting Information Report
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