Engineering & Mining Journal

AUG 2018

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REGIONAL NEWS - U.S. & CANADA 12 E&MJ • AUGUST 2018 www.e-mj.com Lithium Americas Advances Thacker Pass Project in Northwest Nevada Lithium Americas has reported the results of a preliminary feasibility study (PFS) of its large-scale Thacker Pass lithium carbonate (Li 2 CO 3 ) project in northwest Nevada and based on the results has outlined a time- table for two phases of development. Phase 1 will have production capacity of 30,000 metric tons per year (mt/y) of battery-grade Li 2 CO 3 beginning in 2022. Phase 2 will double capacity to 60,000 mt/y in 2026. Given the soft nature of the Thack- er Pass deposit, minimal blasting and crushing is anticipated. Mining will be by continuous miners. The open-pit mine plan is based on 3.1 million mt of proven and probable reserves of Li 2 CO 3 equivalent at a grade of 3,283 ppm lithium, supporting a mine life of 46 years. The strip ratio is 1.6:1, waste-to-ore. The ore will be processed in a leaching circuit using sulphuric acid to liberate the lithium from the claystone. After leaching, the lithium-bearing solution will be purified using crystallizers and reagents to produce battery-grade Li 2 CO 3 . Lithium Americas col- laborated with Ganfeng Lithium, of China, to develop and test the process flowsheet. An on-site sulphuric acid plant will cre- ate value for the project by reducing trans- portation costs, producing steam and elec- tricity, and generating revenue through sale of excess acid and electricity to the market. Capital costs to develop Thacker Pass Phase 1, including a 19% contingency, are estimated at $581 million. Capital costs for Phase 2 are estimated at $478 million. Average life-of-mine operating costs are estimated $2,570/mt of Li 2 CO 3 , net credits from sulphuric acid and electricity sales. Average life-of-mine all-in sustaining costs, including royalties and sustaining capital costs, are estimated at $3,043/mt. At a price of $12,000/mt for bat- tery-grade Li 2 CO 3 , cashflow from Phase 1 production is forecast to fully fund Phase 2 capital costs. The Thacker Pass project is designed to avoid environmentally sensitive and rugged terrain, which is expected to re- duce permitting timelines, construction risk and costs. The plant and tailings facilities are in a low-lying area immedi- ately adjacent to the pit. The flat and ex- pansive terrain allows for a very compact footprint, while also allowing for future potential expansions. "The strong economics demonstrated by the Thacker Pass PFS clearly support the commercial potential for this large, high-grade, clay-based lithium resource," said Alexi Zawadzki, president of Lithium Americas' North American Operations. "With the experience of our team and le- veraging our strong partner relationships, we plan to rapidly advance this scalable project to become the leading source of lithium production in the USA." Equinox Planning Restart at Castle Mountain Gold Mine Equinox Gold has released the results of a prefeasibility study of redevelop- ment of the Castle Mountain gold mine in southeast California. The project will be developed as an open-pit, heap-leach mine, starting with Phase 1 run-of-mine heap leaching of stockpile material from previous operations and ramping up to a full restart in Phase 2, which will in- clude milling of a limited stream of high- er-grade material and run-of-mine leach- ing of the balance. Castle Mountain has 3.6 million ounc- es (oz) of proven and probable gold re- serves. Equinox anticipates that the proj- ect will create a robust, low-cost mine producing an average of more than $83 million after-tax operating cash flow per year in the current gold price environment over a 16-year mine life. Phase 1 production is estimated at 45,000 oz per year (oz/y) of gold over a period of one to three years. Phase 2 is planned to produce an average of 203,000 oz/y during years four through 14. Total production is estimated at 2.8 million oz. Phase 1 commissioning is planned for late 2019. Capital expenditures are estimated at $52 million to develop Phase 1 and $295 million to develop Phase 2. Life-of-mine all-in sustaining costs of production are estimated at 763/oz. The Castle Mountain mine produced more than 1.3 million oz of gold from 1992 to 2004, when production ceased due to low gold prices. The property was substan- tially reclaimed from 2004 to 2012, but 3.6 million oz of gold reserves remain and are economic at current gold prices. Permits to operate the mine have been maintained in good standing. During Phase 1 construction and opera- tions, Equinox will undertake permitting and water studies required to commence Phase 2 production. The Castle Mountain site plan shows how the full-life footprint stays within the permit boundary.

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