The Boorara gold project is located in Western Australia. Credit: Horizon Minerals Limited.
Trial open-pit mining was undertaken at the site in 2016. Credit: MacPhersons Resources Ltd.
The Boorara mine is 100% owned by Horizon Minerals. Credit: Horizon Minerals Limited.

Boorara gold project involves the development of an open-pit mine and processing facility in the city of Kalgoorlie-Boulder, Western Australia.

The project comprises three deposits, namely Regal in the north, Royal in the south and Crown Jewel in the centre.

The stage one feasibility study for the project was completed in February 2020. The mine optimisation and design, scheduling and economic evaluation were concluded to commence production from stage one of the project in 2020. The first stage is estimated to have a mine life of eight months.

The plan includes the development of three starter pits for open-pit and toll milling.  A grade control programme conducted at the project during the fourth quarter of 2019 yielded high-grade results across the three deposits.

The Boorara property was acquired by MacPhersons Resources from Polymetals Mining in October 2011. The mine is currently 100% owned by Horizon Minerals, which was formed by the merger of Intermin Resources and MacPhersons Resources in June 2019.

Boorara gold project location, geology and mineralisation

The Boorara gold project is located on the eastern edge of Kalgoorlie-Boulder, 6km north-north-west of Golden Ridge in Australia.

The project extends over the mining leases M26 / 29, M26 / 277 and M26 / 318. It is situated 1km south-west of the Nimbus site and 10km east of Kalgoorlie’s Super Pit gold mine.

The mine is composed of predominantly oxide and transitional material enclosed within its maiden ore reserve. The orebody of the mine lies near the surface and has low strip ratios with exceptional metallurgy.

Boorara’s gold mineralisation extends to more than 1.5km striking north-west at 330°. It is present in a series of north-west dipping stacked quartz vein arrays.

Boorara gold project reserves

The Boorara gold project stage one is estimated to contain proven and probable reserves of 159,000t graded at 1.9 grams per ton (g/t) of gold (Au).

Mining at Boorara gold project

The Boorara gold project will employ open-cut mining with conventional truck and shovel operations. Initial mining activities will involve free digging near the surface. A mining contractor will be engaged to carry out the mining operations while Horizon will be responsible for technical and managerial supervision.

Prior to ore mining, waste overburden of 6m will be removed and ore from the recently completed grade control model will be marked up.

The company is planning to conduct mining on lower bench height and smaller bucket size to reduce dilution and improve ore recovery.

Optimisation studies were undertaken by using Whittle software for open-cut mining while mine designs were carried out on optimised shells.

Small-scale trial open-pit mining and toll milling at the project’s Royal area were completed in 2016. The trial pit was excavated to a depth of 20m and produced 1,550oz of gold at a grade of 1.73g/t Au and a  recovery rate of 91.5%.

Processing at Boorara gold project

The mined ore will be transported to Golden Mile Milling’s processing facility in Lakewood. Located 7km away from the mine, the mill will process the ore on a campaign basis. The mined ore will be stockpiled for processing, which will begin after two months of mining at a rate of approximately 25kt per month.

The one million tons per annum (Mtpa) conventional carbon-in-leach plant will treat the ore through a conventional crushing, grinding and gravity circuit. Gold is extracted from the ore using a standard carbon-in-leach gold extraction process.

Infrastructure at Boorara gold project

Horizon intends to use temporary and nominal mining infrastructure at the site to support the operations. The site is accessible via an unsealed road from the Bulong Road.

“The water table is located 70m below the surface of the mine, avoiding the need for dewatering facility.”

The existing offices at the site are connected to grid power. Water needs for dust suppression operations will be met from the nearby Chappell bore and a water storage dam.

The site will witness minor upgrades of existing establishments and roads, along with the construction of a small temporary office, hard-stand and a workshop.

Contractors involved

Minecomp was contracted to conduct the ore reserve study while BM Geological Services prepared geology and resource estimates for the feasibility study.

ALS Metallurgy and Bureau Veritas Minerals were responsible for metallurgical test work during the study.

Other consultants and companies that supported the study include Rockwater, Strategen-JBS&G Environmental Consultants and Green Geotechnical. MLG Oz undertook the trial mining for the project.