Mount Morgans Gold Project, Australia
Mount Morgans gold project is a brownfield gold mine located 25km south-west of Laverton gold district, the second biggest gold province in Australia after Kalgoorlie. The Mount Morgans project is 100% owned by Dacian Gold.
Dacian Gold initiated a three-year exploration programme in 2012 and completed the scoping study of the project in September 2015. The results of the project's feasibility study (FS), which were announced in November 2016 , estimated Mount Morgan to contain ore reserves, which can be mined over an eight-year mine life.
A pre-feasibility study (PFS) for expansion of the mine was also conducted that increased the ore reserve estimate to 1.65 million ounces (Moz).
The project is estimated to require a capital investment of A$220m ($161.25m) including A$172m ($126.07m) for site-based infrastructure and A$48m ($35.18m) for mine establishment. The mine expansion is estimated to cost A$3m ($2.19m).
Gold production at the mine is expected to begin in the first quarter of 2018.
Mount Morgans gold project geology and mineralisation
The Mount Morgans gold project includes three main prospects, namely Westralia, Jupiter and Transvaal. The Westralia mine area includes the Beresford and Allanson underground mines.
Mineralisation at the Westralia prospect includes sulphide replacement in steeply north-east dipping banded iron formation (BIF), whereas the Jupiter prospect consists of steeply east dipping mesothermal gold mineralisation related to syenite intrusions within altered basalt.
The Transvaal prospect features steeply east dipping mesothermal gold mineralisation primarily within altered basalt.
Reserves at Mount Morgans
Mineral resources at the Mount Morgans gold deposit are estimated at 3.3Moz, of which 2.2Moz is measured and indicated.
Initial ore reserve at the mine is estimated to be 18.6Mt graded at 2.0g/t Au, containing 1.2Moz of gold. Of the total reserves, 3.8Mt graded at 4.5g/t Au, containing 557 thousand ounces (Koz) of gold, will be mined from the underground mines, of which the Westralia mine area will contribute 492koz of gold, while 14.8Mt graded at 1.4g/t Au, containing 643Koz of gold, will be mined from a single deep open-pit from the Jupiter mine area.
The expansion PFS, which assessed the impact of expanding only the Westralia mine, estimated that the expansion would increase the ore reserve from 18.6Mt to 21.4Mt grading 2.4g/t Au and containing 1.65Moz of gold. The average gold production upon expansion is estimated to be 197,000oz a year during the first seven years.
Mining and processing at Mount Morgans gold mine
The Westralia prospect will be developed as a large underground mining complex, while the Jupiter prospect will be a large open-pit located in the eastern half of the project. Jupiter will contribute approximately 80% to the total tonnage, while the underground mines will contribute the remaining.
The Jupiter open-pit mining complex includes three potential open-pits namely Heffernans, Doublejay and Ganymede deposits. Conventional drill, blast, load and truck haulage method will be used at all the open-pits, while top-down, narrow sub-level open stoping mining technique will be adopted for the underground mines.
A new 2.5 million tonne per annum (Mtpa) processing facility has been proposed to be built for processing the mined ore. The average expected gold recovery from the proposed process design is 90.7%.
The processing facility will be located adjacent to the Jupiter pit and incorporate an SABC configuration, which includes single-stage crushing process, semi-autogenous (SAG) mill, ball mill and pebble crushing circuit with gravity and carbon-in-leach (CIL) gold recovery.
Infrastructure at the Western Australian gold project
Being a brownfield site, the Mount Morgans project benefits from existing infrastructure, including road access through sealed highways, a new gas pipeline passing through the project area and a public airport at Laverton. The site also includes a bore field that will supply low-salinity raw water to the proposed treatment plant and a Telstra microwave tower for site-based communications.
The proposed new infrastructure includes a processing facility, tailing storage facility, raw-water supply infrastructure and an accommodation village. In addition, mine service area facilities and an administration complex will be established apart from redevelopment of haul roads and service roads, and installation of mobile infrastructure.
A new 20MW power station is also proposed to supply power for the processing plant operations. It will be located adjacent to the proposed processing plant in the Jupiter mine area.
Power to the Westralia and Transvaal mine areas and accommodation facilities will be supplied through an 11kV overhead power line.
The feasibility study for the project was compiled by GR Engineering Services. Other consultants who assisted in estimating ore reserves include Orelogy Consulting, Entech, Peter O'Bryan & Associates, Groundwater Resource Management, Blueprint Environmental Strategies, ATC Williams and Walker, and Newman & Associates.