Mount Marion Lithium Project, Australia

Located 40km south-west of Kalgoorlie, in the Goldfields region of Western Australia, Mount Marion lithium project contains the world's second biggest high-grade lithium concentrate (spodumene) reserves. The Mt Marion project was approved for development in October 2010 and construction began in 2015. Production of lithium concentrate from the mine started in February 2017.

The spodumene mineral from the mine is processed to produce lithium carbonate. It is mainly used in the production of batteries for hybrid cars.

"In February 2011, the joint venture companies formed an entity called Reed Industrial Minerals (RIM) to develop the lithium project."

A pre-feasibility study conducted by Hatch and Neometals (previously Reed Resources) estimated the demand for lithium carbonate in Asian markets to be 17,000t a year produced by processing 120,000t of chemical-grade spodumene concentrate.

Lithium carbonate is also used in several other industries such as lubricants, glass, pharmaceuticals, air-conditioning and ceramics. By-products recovered from the mining operations include potassium feldspars, tantalum and mica.

Ownership of the Western Australian mine

Development of lithium mine was initiated by a joint venture between Neometals and Mineral Resources (MRL). In October 2009, both companies signed a farm-in agreement, which stated that MRL would fund development, construction and operations of the processing plant, while Neometals would have 100% ownership. MRL would have shared 40% of the net profits.

However, in February 2011, the joint venture companies formed an entity called Reed Industrial Minerals (RIM) to develop the lithium project.

The agreement was amended to include MRL owning a 30% stake in RIM and continue funding and operating the mine. Holding a 70% interest, Neometals, aims to become one of the leading producers of lithium spodumene. Jiangxi Ganfeng Lithium acquired a 25% shareholding in RIM in 2015.

Geology and reserves of the Mount Marion area

Western Mining Corporation (WMC) conducted an exploration study at the Mount Marion tenements between 1960 and 1980. The study estimated a possible production of 5,000t of lithium carbonate a year.

The mine was expected to have a mine life of ten years. A pre-feasibility study was completed by Associated Minerals in 1996. The mine produced spodumene concentrates, ranging from 6.5% to 7% Li2O in the pilot tests.

The recoveries were to range from 75% to 83%. The exploration activities were, however, put on hold thereafter.

In August 2010, the resources estimated at the mine were defined as being 10.5Mt of mineralised spodumene pegamites at 1.4% Li2O (lithium oxide) with a contained Li2O reserve base of 146,500t. In July 2011, the total reserves at Mt Marion were estimated to be 1.49Mt at 1.3% Li2O for 201,000t of contained Li2O and 1.2% of Fe2O3. In 2016, the resources were estimated to be 77.8Mt at 1.37% Li2O and 1.09% Fe2O3.

Hellman & Schofield (H&SC) was contracted for providing a geological model for the mineral resource estimates.

Mining and drilling phases at Mt Marion

The joint venture companies have two mining lease permits to extract pegmatites within the M15/999 and M15/1000, including outcropping.

"Lithium carbonate is also used in several other industries such as lubricants, glass, pharmaceuticals, air-conditioning and ceramics."

Resources were estimated by geological mapping, drilling and sampling. With additional estimates coming from a further 114 drillholes, for a total of 138 holes drilled in 2011.

Phased resource definition drilling identified the pegmatites at the No.1 Deposit, No. 1W Deposit, No.2 Deposit, No. 2W Deposit on M15/1000 and No.4 Deposit on M15/999. The resources occur along downdips and strikes in the region. The interpretation of deposits was provided by Bryan Smith Geosciences.

Neometals increased the life of the open-pit mine through strike and depth extensions at the M15/1000 deposits by drilling 49 additional holes.

A new location, Area 6, has also been identified to contain pegmatite. It acts as an extension of the deposit four drilling programme in the southern part of M15/1000.

Ore processing and production of lithium

Lithium is produced by mining and crushing hard, granite-like rocks hosting the spodumene mineral. Spodumene is processed to produce lithium carbonate.

Mineral Resources built a modular processing plant and installed other ancillary equipment, with a capacity to produce 17,000t of +6.5% Li2O concentrate a month.

The mine is expected to initially produce 200,000t/y of Li2O at 6% chemical grade spodumene concentrate, 60,000t/y of mica and 30t/y of tantalite concentrate. The processing plant includes a modular beneficiation circuit to increase production in future based on customer requirements.