Pilgangoora Lithium-Tantalum Project, Pilbara, Australia


Pegamatites

Pilbara Minerals' wholly owned Pilgangoora Lithium-Tantalum Project is located approximately 120km south of Port Hedland in the Pilbara region of Western Australia, and roughly 55km from its flagship Tabba Tabba Tantallum Project.

The pre-feasibility study (PFS) for the project was completed in March 2016, whereas the definitive feasibility study (DFS) is scheduled for completion in the third quarter of 2016. Construction works are expected to start in early 2017 and production is anticipated to start in late 2017.

The overall investment to bring the project into production is estimated to be A$184m ($141m approximately) and the mine is estimated to have an initial production life of 15 years. A 15,000m drilling campaign is currently underway as part of the DFS, which could further extend the life of the mine.

The project aims to produce 330 kilotonnes per annum (ktpa) of 6% spodumene concentrates (48ktpa of lithium carbonate-equivalent) and 274,000lb a year of tantalite.

Pilgangoora lithium-tantalum project geology and mineralisation

Covering an area of approximately 31km², the project hosts three mining licences, namely M45/78, M45/333 and M45/511, as well as two exploration licences, EL45/2232 and EL45/2241.

It is located within the Archean North Pilbara Craton, hosting the East Strelley Greenstone Belt, which is composed of a series of steeply dipping mafic meta-volcanic rocks and amphibolites.

The pegmatites extend more than 7km and the mineralisation occurs in a number of north-south trending pegmatites, with strike lengths reaching approximately 1,250m. The pegmatites are comprised of albite, quartz, muscovite and spessartine garnet, with the mineralised zones hosting lepidolite, spodumene, tantalite and cassiterite, and small amounts of microlite, tapiolite and beryl.

Reserves

As of February 2016, the project is estimated to hold combined indicated and inferred resources of 80.2Mt grading 1.26% Li2O (spodumene), containing approximately 1Mt of lithium oxide, 42.3Mt grading 0.02% Ta2O5 (tantalum), containing 18.3Mlbs of tantalum oxide.

The probable reserve is estimated at 29.5Mt grading 1.31% Li2O, 134ppm Ta2O5 and 1.18% Fe2O3. The project is touted to host the world's second biggest spodumene-tantalum resource.

Mining and processing at the Pilbara lithium-tantalum project site

The mining method envisaged for the project is open-pit mining integrating 100t truck and hydraulic excavator operations, and drill and blast activities.

The proposed concentrator plant will have an ore processing capacity of two million tonnes per annum (mtpa) and a nominal capacity of 250 tonnes per hour (tph). It is designed to produce chemical-grade spodumene, technical-grade spodumene and tantalite concentrate.

The concentrator will primarily integrate a two-stage crushing circuit, a feed preparation facility, a dense media preparation circuit, a gravity preparation circuit, a grinding circuit, and a flotation circuit incorporating a wet magnetic separation facility to reduce the quantity of iron in the technical-grade spodumene product.

Infrastructure for the Western Australian lithium-tantalum mine

The project benefits from its close proximity to existing major roads, an airstrip, and the Port of Hedland. A reverse osmosis water treatment plant will be installed to provide potable water and the electricity requirements will be met by a diesel-powered generator.

The mining infrastructure will include a maintenance workshop, offices, crib rooms and amenities, fuel farm, water dams and dewatering systems. Other major infrastructure for the project will include a tailings management facility, mine waste stockpiles, an airstrip, and accommodation facilities.

Off-take MoUs for Pilbara Minerals' lithium-tantalum project

As of March 2016, Pilbara Minerals has signed off-take memorandum of understandings (MoUs) with eight different chemical and technical-grade customers located in China, Korea, Japan, North America and Europe.

Key players involved

Major consultants involved in preparing the DFS include Como Engineers for the process plant infrastructure, non-process plant infrastructure and the metallurgical studies, Trepanier for the geological and the resource estimate studies, MiningPlus for the mine design studies, ATC Williams for the tailings management facility and geotechnical studies, and Groundwater Resource Management for the hydrogeology and hydrology studies.

The metallurgical testworks for the PFS were conducted at Dorfner Anzaplan's facility in Germany, Nagro Mineral's facility in Perth, and ALS' laboratories in Perth and Adelaide.