Nevada Lithium Resources Inc. (CSE: NVLH; OTCQB: NVLHF; FSE: 87K) (“Nevada Lithium” or the “Company”) is pleased to provide a technical update on its 2024 metallurgical program at its 100% owned Bonnie Claire Lithium project (the “Project” or “Bonnie Claire”), located in Nye County, Nevada.
Nevada Lithium’s CEO, Stephen Rentschler, comments:
“The high-grade Lithium and Boron mineralization we have identified over the last two drilling programs presents additional opportunities that were undiscovered when the Company’s Preliminary Economic Assessment (“PEA”) was completed three years ago. With Bonnie Claire now looking to be an analog to Ioneer Ltd.’s Rhyolite Ridge deposit (“Rhyolite Ridge”), the logical next step was to explore relationships with companies instrumental in the development of Rhyolite Ridge.
We are happy to report that we have engaged Fluor Enterprises, Inc. (“Fluor”) to develop the metallurgical processes and plant design that will be incorporated into an updated PEA”, he continued. “The updated PEA will, for the first time, reflect the impact of the tremendous grades and intercepts of Lithium and Boron that we have encountered in the lower high-grade Lithium and Boron mineralized zone at Bonnie Claire.
Fluor is an internationally recognized firm with comprehensive capabilities that have been utilized in some of the world’s largest and most significant Lithium projects, such as Ioneer’s Rhyolite Ridge, Albemarle Corporation’s Meishan Project, Jindalee Lithium Ltd. and Aurora Lithium SA, among others. We think that Fluor’s participation in our Project clearly reflects the increasing industry recognition of Bonnie Claire’s position among the world’s top tier of Lithium and Boron projects.”
Highlights:
- Acid leaching has become the preferred option for treating material with high Lithium and Boron content at Bonnie Claire. Preliminary acid leach test work gives 97% overall Lithium recovery and 98% overall Boron recovery. To date, acid leaching has been advanced as the typical recovery process for Lithium-bearing Nevada claystone projects.
- A conceptual two-stage acid leach flowsheet proposes a Boron stream to produce boric acid and a Lithium stream for generating lithium carbonate.
- Thermal treatment may be an option for processing high grade Lithium material with low Boron content at Bonnie Claire. Processing claystone material with 1,000 ppm Lithium and 1% searlesite achieved 80% Lithium recovery.
- Fluor Enterprises, Inc. of Greenville, South Carolina and Kemetco Research Inc. of Richmond, BC (“Kemetco”) will oversee future test work and develop a process plant design for the updated Preliminary Economic Assessment.
- Test work should conclude in early 2025, with PEA completion at the end of Q1 2025.
Previous Work
The 2021 Preliminary Economic Assessment for Bonnie Claire favored thermal treatment of mineralized material. This treatment included calcination of material with the addition of sodium sulfate, followed by hot water leaching. This thermal treatment achieved high Lithium recoveries of up to 80%. Additional work by Hazen Research Inc. (“Hazen”) included the successful production of battery-grade lithium carbonate (see the Company’s news release dated February 27, 2023). The thermal process on a bulk (300 kg) sample confirmed the process using the same flowsheet but achieved a lower 61% Lithium recovery rate. This sample contained about 11% searlesite. The lower recovery was likely due to agglomeration by the presence of searlesite.
Newly Identified Boron
The Company has identified a thick zone of gently dipping, high-grade mineralization at depth. This zone exhibits both high-grade Lithium mineralization, including 3076 ppm Lithium over 1100 ft (November 20, 2023 news release) and high-grade Boron mineralization, including 15,001 ppm Boron over 560 feet (May 22, 2024 news release).
Boron mineralization is contained in the mineral searlesite, which makes up to 38% of mineralized rock in the lower zone. Hazen has demonstrated that a high searlesite content reduces the melting temperature of the material, inhibiting effective calcination. While the Company has concluded that calcination is not preferred for the high-grade material at Bonnie Claire, it may still be an option for material with lower searlesite content, such as the lower-grade upper zone.
Two-Stage Acid Leaching
To formulate a suitable recovery method for high-grade Lithium and Boron material at Bonnie Claire, the Company asked Hazen to conduct preliminary acid leach benchwork and to develop a conceptual acid treatment process to recover both Lithium and Boron. To date, acid leaching has been advanced as the typical recovery process for Lithium-bearing Nevada claystone projects. Fluor has also advanced the use of acid leach in the Definitive Feasibility Study for Rhyolite Ridge, the only other known Lithium-Boron claystone deposit in Nevada.
Hazen has developed a conceptual two-stage leaching approach using:
- An initial dilute acid leach at 160 kg acid/t solid, to facilitate the recovery of Boron
- A second concentrated 500 kg acid/t solid for the recovery of Lithium
Using this two-stage leaching approach, Hazen achieved a 97% overall Lithium recovery, together with a 98% overall Boron recovery.
The two-stage leaching approach produces two filtrates: a high Boron stream to produce boric acid and a high Lithium stream for generating lithium carbonate. However, there may not be a benefit to a two-stage leach if Boron content is low. A single stage leach has the advantage of requiring less solid/liquid separation stages. The decision to use countercurrent leaching for better acid utilization will be determined after further test work is performed.
Fluor and Kemetco
Following the successful preliminary acid leach benchwork and conceptual flowsheet by Hazen, Nevada Lithium has accepted a proposal from Fluor and Kemetco. The companies will oversee and perform future benchwork and develop a process plant for inclusion into an updated PEA.
Fluor’s Lithium Center of Excellence will set-up and coordinate a test work program to take place at Kemetco’s lab facility. The key focus will be to prove the make-up of a conceptual acid-leach circuit. Fluor and Kemetco’s joint expertise in developing test work programs for Lithium compounds of similar metallurgy will play an instrumental role in bringing a high level of certainty to the Project flowsheet.
It is estimated that the test work program will conclude in early 2025. The development of a process plant will then feed the preparation of the updated PEA report pertaining to metallurgy, capital, and operating expenses (CAPEX and OPEX, respectively). Global Resource Engineering will prepare an updated PEA, with an estimated completion date by the end of Q1 2025.
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