Andy Well Gold Mine, Murchison

Blasting activity being done for providing underground access at Andy Well. Image courtesy of Doray Minerals.

Underground mining is being carried out at the Wilber Lode section of Andy Well mine. Image courtesy of Doray Minerals.

The Carbon in Pulp processing plant at Andy Well processes 170,000 tonnes of ore and includes a two stage crushing circuit. Image courtesy of Doray Minerals.

Andy Well is an open pit and underground gold mine located within the Meekatharra North Project in the North Murchison region of Australia. Doray Minerals fully owns the project and expects to produce 74,000 ounces of gold per annum.

The mine extends over an area of 1,100ha and is currently expected to have a mine life of 3.7 years.

The mining lease for Andy Well was granted in April 2012 by the Western Australian Department of Minerals and Petroleum. Bankable feasibility study was completed in July 2012 and the mining activities began in November 2012. The mine commenced production in August 2013.

Andy Well mine geology

Andy Well is a part of Murchison mineral field of Yilgarn Craton. The craton is a sequence of Archean rocks formed by the greenstone belts. The granite and granodiorite intrusions of basalt and porphyry rocks form the rock sequence.

The mine is situated at an altitude of 470m to 500m. The mine’s strata comprise of colluviums containing alluvium, quartz and rock formations.

Andy Well mine reserves

The Andy Well Gold mine had maiden reserves of 248,000oz of high-grade gold. The combined measured and indicated resources were estimated at 444,000oz. Ongoing exploration is expected to increase the reserves further.

Andy Well mine production

The mine produced 24,100 ounces of gold grading 13.1g/t in the quarter ending in December 2013.

Mining and ore processing at Andy Well gold mine

Doray started underground mining at the Wilber Lode section after completing mining at the open-pit region. A cross-cut was laid from the bottom of the open-pit in order to access the section.

The run of mine project is expected to extract 733,000t of ore per annum. The extracted ore is processed through a two stage crushing system and grinded in a ball mill within a closed circuit.

The centrifugal gravity concentrator executes the intensive cyanidation of the concentrate. Leaching and adsorption of gold takes place before extraction of gold.

Details of the processing plant and tailings facility at Andy Well

The Carbon in Pulp processing plant installed at the mine carries out the ore processing. It consists of a two stage crushing circuit and a cyanide leach extraction system. The processing capacity of the plant is 170,000t of ore per annum.

A tailings storage facility and a process water storage facility supplements the processing plant. The tailings facility has a storage capacity of 170,000t of dry slurry per year.

Infrastructure and construction at Andy Well mine

The infrastructure facilities include a landfill facility for the disposal of inert waste generated at the mine. The landfill facility is at 100m south of the tailings storage facility and constructed in an area of 12,800m².

A 3MW captive power station is included at the plant site. Eight diesel generators of 500kW are used for power generation.

Workers were accommodated at the 126-person accommodation village at Meekatharra.

Financing for the Andy Well gold mine

The Commonwealth Bank of Australia funded the Andy Well Gold project to meet the capital expenditure requirements of approximately $50m.

Doray also raised $27.95m through financial placement and obtained a fully underwritten Entitlement Offer of $11m.

The project achieved financial closure in September 2012.

Contractors involved with Andy Well mine development

The Engineering, Procurement and Construction contract for the processing plant was awarded to GR Engineering. The scope of the $28m contract also included provision of site infrastructure.

The contract for mining at the open-pit region and other civil earthwork services was awarded to MACA Civil.

GBF Underground Mining was awarded the contract for providing the underground mining services at Andy Well.

Nordic North was awarded the contract for the construction of the diesel-fired power plant at the mine site and the accommodation facility at Meekatharra.

The contract for the construction of tailings storage facility and process water storage facility was awarded to Coffey Mining.