Murchison Goldfield, Australia
Murchison Goldfield is located between Mount Magnet town and Cue town, 600km north-east of Perth, Australia. It is made up of 14 open pit and four underground gold mines with most of the reserves contained in Tuckabianna, Comet, Moyagee and Eeyla deposits. The project is owned by Silver Lake Resources.
Murchison goldfield includes a centralised carbon-in-leach (CIL) gold processing facility that processes the ore extracted from the project's open-pit and underground mines and its tenements.
Silver Lake Resources commenced the mining activity at Murchison in 2012 and poured the first gold in February 2013. Commercial production commenced in June 2013. The goldfield is expected to have a life of eight to ten years.
Further exploration is being conducted in the Sherwood, Ridge 456, Hollandaire and Rapier South deposits to expand the reserves. Hollandaire contains huge copper deposits along with gold, silver and zinc.
Murchison gold mine geology and mineralisation
Murchison goldfield contains volcanic rocks of the Gabanintha and Golconda Formations. The rocks host high-grade volcanogenic massive sulphide mineralisation.
Gold mineralisation is mostly within banded iron formations. It is also found in the quartz-feldspar margins and in the rafts of greenstone stratigraphy.
Fine-grained basalt rocks are found at the project site. Coarse grained gold occurs as iron rich sediments divided into footwall and hanging wall lodes. Higher grades occur in steeply dipping shoots.
Murchison mine reserves
The Murchison goldfield is estimated to contain reserves of 4.27 million ounce (moz) of gold. The combined JORC-compliant resource estimate is 19moz of gold.
Mining and processing at Murchison gold mine
Gold mining at Murchison is currently performed at the Genesis, Caustons North and Comet South mines. Conventional drill and blast method of mining is applied. The mined ore is transferred to the 1.2 million tonne per annum (mtpa) capacity central processing facility.
The processing facility includes a crushing, grinding, milling and leaching installation at Tuckabianna. Gold particles will be recovered from the ore in a gravity circuit before conducting cyanide leaching.
The processing facility includes a base metals circuit with a prospect to transform the facility into a base metal grinding and recovery unit.
Murchison gold field infrastructure and construction details
Construction activities at Murchison involved the setting up of a processing facility, gravity circuit, tailings dam lift, storage tanks, gold room, and CIL circuit. The milling and surface infrastructure cost $91m.
The construction of the 1.2mtpa capacity processing facility at Tuckabianna included dry commissioning of the crushing circuit, wet commissioning of the ball mill, and the development of the crushing and grinding units. The crushing circuit has a capacity of processing two million tonnes per annum and the ball mill can process 135t per hour.
The gold room at the mine site is used to pour gold and carbon stripping. It also includes a gravity circuit.
The power station at Murchison is a 10.2MW diesel-fired plant and includes six generators running on a continuous basis.
Workers are accommodated at a 250-person camp at the village of Cue.
Financing for the Murchison goldfield development
Silver Lake Resources utilised internal cash flows and cash reserves for the exploration and development of the Murchison goldfield project.
National Australian Bank also partly financed the project.
Contractors involved with the Murchison goldfield development
Boddington Gold Mine (BGM) is located about 130km south-east of Perth in Western Australia.
The contract for delivery of the CIL processing plant to Tuckabianna deposit was awarded to Pacer Corporation, a subsidiary of Resource Development Group. The $35m contract includes relocation and refurbishment of equipment from the Tarmoola processing facility.
Alliance Mining was awarded the contract to conduct open-pit mining operations at Murchison.
Redpath Contracting Services was awarded the contract for the underground mining work.
The contract for constructing and operating the accommodation village at Cue was awarded to NT Link.