McArthur River Mine

McArthur River Mining Pty Ltd (a Glencore company)

The McArthur River Mine (MRM) is an existing lead and zinc mine that has been operating since 1993. Following the completion of an EIS and approval by Government, MRM commenced as an underground mine with the assumption that it would last for 20 years. The underground mine ceased operating in 2005.

The Phase 2 expansion changed the underground operation to an open cut operation to secure the long-term viability of the operation, which was becoming uneconomical due to reduced output rates and safety issues. Phase 2 increased the mining rate from 1.6 million tonnes (Mt) per year to 1.8 Mt per year (Mt/y). The proposal included diverting Barney Creek and a 5.5 km length of the McArthur River around the mineral resource, establishing a flood protection bund around the pit area, and constructing above-ground overburden emplacement facilities for waste rock disposal. Total reserves increased to 43 Mt and the proposed mine life extended to 25 years.

The Phase 3 Development Project was assessed by the Department of Natural Resources, Environment, the Arts and Sport in 2012 and approved in 2013. Phase 3 involved an approximate doubling of the open pit surface area and depth (increased footprint from 145 ha to 210 ha and increased depth from 210 m to 420 m). The mining rate also increased from 2.5 Mt/y to 5.5 Mt/y of ore and production of zinc-lead concentrate increased from 360 000 Mt/y to 800 000 Mt/y), and extended the mine life by nine years, to 2036.

The basis for the assessment of the MRM Overburden Management Project by the NT EPA was the reclassification of waste rock. The classification system used by the Proponent while operating the open cut mine to 2014 did not match the actual characteristics of the rock being mined and led to a significant under-estimation of the volume of reactive (potential to generate acidic/metalliferous/saline drainage) waste rock. The Overburden Management Project was proposed to manage this issue.

The environmental assessment history of the McArthur River Mine is presented below.

MRM Overburden Management Project 2018

MRM Phase 3 Development Project 2012

MRM Open Cut Amendment Project 2006

MRM Phase 2 Open Cut Project 2006

Mt Isa Mines - McArthur River Project 1992