MTG036 Mt Garnet TSF Remediation

Major Civil Bulk Earthworks - Mt Garnet TSF Remediation Project

The Department of Natural Resources and Mines, Manufacturing and Regional and Rural Development (NRMMRRD), Technical Services team manages the Abandoned Mine Lands Program (AMLP) across Queensland. The objective of the AMLP is to minimise public health, safety, environmental and property risks arising due to abandoned mines.

One of the sites within this program is the former Mt Garnet polymetallic open-cut and underground mine 3 hours southwest of Cairns.

The site contains an open cut pit, a mineral processing plant and associated infrastructure, a large tailings storage facility (TSF), a core yard, several evaporation and process water dams. A second tailings storage facility was partially constructed but was never completed or used to store tailings.

Capping of the TSF has been identified as a high-priority remediation activity for the site.

This scope of work involves the execution of remediation works for the Mt Garnet TSF, including:

• Pre-mobilisation activities, including a half day workshop with the Principal to review design and construction aspects, plus preparation of relevant management plans;

• Timber and vegetation clearing along the spillway alignment;

• Spillway excavation, with material used to achieve a suitable free-draining landform on the tailings surface prior to capping works.

• Spillway erosion protection works, including armour rock lining and hydro-mulching batters;

• Placement of a trafficability layer across the tailings surface.

• Installation of a Geosynthetic Clay Liner (GCL)

• Placement of a 300mm clay cover layer across the GCL.

• Placement of a 300mm rock cover layer across the clay cover.

• Seeding (drill seeding) and fertilising of works in nominated zones, such as the TSF No.2 basin and material stockpile borrow areas.

• Any other works identified and agreed upon by both parties when subsequent Issued For Construction (IFC) drawings are released.