The Havieron project in Western Australia is a greenfield gold and copper deposit currently in development.
The project, located in Paterson region, was discovered in 2018.
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It is being developed by a joint venture (JV) between Australia-based Newcrest Mining (70%) and UK-based Greatland Gold (30%).
Construction of the box cut for the underground mine began in February 2021.
It was followed by the release of a Pre-Feasibility Study (PFS) of the South-East crescent in October 2021. The feasibility study is slated for December 2022 quarter completion.
Havieron is expected to produce first ore in the first half of 2024, with gold and copper production to commence in the second half of the same year.
In August 2022, Newcrest chose not to exercise an option to acquire an additional 5% interest in the JV following a non-binding offer from Greatland.
Greatland Gold also executed debt and equity agreements in September 2022 to secure up to A$340m ($213.44m) to fund its share of Havieron development into production.
Location
The Havieron project is located in Pilbara around 450 km east south east from the town of Port Hedland within Mining Lease M45/1287.
The site is approximately 45km east of Newcrest’s Telfer gold mine. The proximity will enable Havieron to utilise the existing infrastructure and processing plant at the Telfer, a move that will reduce the capital expenditure and carbon impact.
Geology and mineralisation
Havieron is regarded as a high-grade gold and copper deposit. The deposit is centred on a deep magnetic anomaly overlain by more than 420m post-mineralisation Permian cover.
Drilling results of the property indicate a 650m x 350m ovoid shaped zone of variable brecciation, alteration and sulphide mineralisation with a north west orientation.
It has identified breccia mineralisation internally and externally to the Crescent zone with open targets.
Mineralisation, hosted by metasedimentary and intrusive rocks, were observed to be more than 1,000m in vertical extent below the post-mineralisation cover sequence.
At Havieron, the exploration works have identified four key target regions- South East Crescent and Breccia, North West Trending Corridor, Northern Breccia and Eastern Breccia.
Gold and copper mineralisation is found in breccia, vein, and massive sulphide replacement styles.
In December 2020, an initial Inferred Mineral Resource Estimate for the Havieron Project was announced to be 3.4 million ounces (oz) of gold and 160,000 tonnes of copper.
Following positive drilling results, Greatland updated the property’s total mineral resource estimate in March 2022 to 5.5 million oz of gold (Au) and 218,000 tonnes of copper (Cu), at 1.9 g/t of gold and 0.24% copper.
The updated ore reserve is 25 million tonnes (Mt) at 3.0 g/t Au and 0.44% Cu for 2.4 million oz of gold and 109,000 tonnes of copper.
Mining Method
The Stage 1 PFS assessed mining methods at the property including the underground Sub-Level Open Stoping (SLOS) method with mining rate ranging between 2-3 million tonnes per annum (Mtpa).
SLOS is a large-scale open stoping method that is conducted over multiple levels simultaneously. Under this method, a stope is backfilled with paste after mining to maintain the stability of the opening and enable mining of adjacent stopes.
The stopes are expected to be mined in a checkerboard fashion starting with primary stopes and then advancing towards intermediate secondary stopes.
The ore produced from the Havieron mine is planned to be transported to Telfer mine via road trains on an all-weather unsealed road. The road has been designed to withstand major floods and maintain access to the mine.
The Havieron mine will be powered by Telfer’s existing gas power station via a 66-kilovolt (kV) overhead line that will run parallelly to the nominated haul road corridor.
The project is expected to have a mine life of nine years.
Ore Processing
The Havieron ore is planned to be processed through a modified Telfer Processing Plant with a single train at 6Mtpa rate on a campaign basis.
The modifications that will be made at the plant will include magnetic separation within the flotation circuit to reduce the amount of pyrrhotite in the final Cu Concentrate. A Carbon in Pulp (CIP) circuit will be installed on the flotation tail and cyanide detoxification circuit.
The tailings from the ore processed will be deposited at the existing Telfer TSF.
Currently, the facility operates two processing trains with a total capacity of around 22 Mtpa.
Contractors involved
Australia-based Derisk Geomining Consultants conducted an independent review of the Havieron mineral resource estimate that was published in November 2020.
Byrnecut, an underground mining contractor, was selected for works such as site establishment, box-cut support, decline development, shotcrete and raise boring services.
Local firm Rockwater was engaged to provide hydrogeological consulting services for the Havieron Project. The scope of work includes the characterisation of poorly-known aquifers within the thick Permian overburden using packer tests, pumping tests, nuclear magnetic resonance surveys, core logging, and correlation with geotechnical datasets.
