Thacker Pass

The Thacker Pass Project is located within an extinct 40x30 km supervolcano named McDermitt Caldera, which was formed approximately 16.3 million years ago (Ma) as part of a hotspot currently underneath the Yellowstone Plateau. Following an initial eruption and concurrent collapse of the McDermitt Caldera, a large lake formed in the caldera basin. This lake water was extremely enriched in lithium and resulted in the accumulation of lithium-rich clays.

Late volcanic activity uplifted the caldera, draining the lake and bringing the lithium-rich moat sediments to the surface resulting in the near-surface lithium deposit called Thacker Pass.

Science Advances published a peer-reviewed academic paper co-authored by Thomas R. Benson, Matthew A. Coble and John H. Dilles on the hydrothermal enrichment of lithium in intracaldera illite-bearing claystones. The research paper describes how lithium-rich hydrothermal fluids altered the lake sediments to a lithium-rich illite, creating the exceptional lithium deposit known today as the Thacker Pass project. Click to view the August 30, 2023 publication.

The McDermitt Caldera has been explored for several minerals since the 1970s during multiple drilling campaigns by many different companies. The ~50 years of drilling confirms that lithium mineralization in smectite clays is extensive throughout the McDermitt Caldera, from the Thacker Pass project area in the south and northward into Oregon. The caldera-wide smectitic mineralization is stratiform, resulting from primary deposition of lithium-rich magnesian smectite clays in a calm lacustrine environment.

Drilling by Lithium Americas identified a second type of lithium-rich claystone, illite, in the vicinity of Thacker Pass. These lithium-rich illites formed when hydrothermal fluids associated the resurgent uplift of the Montana Mountains rose through resurgence fractures in the underlying volcanic rock and spread laterally into the caldera lake sedimentary sequence, altering a section of the smectites to illties.

The lithium-rich claystones at Thacker Pass range in depth from a few meters up to 90 m. The upper clay horizons are dominated by the smectite-type clay with mineralization up to 4,000 ppm, while the deeper horizons are dominated by illite-type clay, with mineralization of up to 9,000 ppm. They are typically overlain by alluvium with an average thickness of approximately 6 m and underlain by hard intracaldera tuff associated with the eruption of the McDermitt Caldera. Interbedded with the lithium-bearing clay are volcanic ashes and a small volume of interbedded hard basaltic beds. Basaltic rock increases in volume towards the southeast of the project area.

Lithium Americas is engaged in an exploration program to expand the resource in the vicinity of the proposed pit area. In 2017, Lithium Americas identified a new target area south of the proposed pit area called the Southwest Basin. Exploration assay results, published in the May 2017 Technical Report, demonstrate that lithium mineralization in the Southwest Basin occurs at grades and depths similar to the proposed pit area. Ongoing geophysical surveys and exploration drilling aims to increase the confidence of the Southwest Basin resource and define the total extent of smectite and illite lithium mineralization throughout the McDermitt Caldera south of the Montana Mountains.

The sedimentary-clay deposit at Thacker Pass will use similar mining techniques to many coal deposits. The shallow (average depth of 300 ft), open-pit will be mined in blocks and actively reclaimed. Once one block is mined to the bottom , mining will move to the next block while backfilling begins in the previously mined area. The backfilled pits would then be capped with topsoil and revegetated with native species.
Block mining allows us to reclaim the land quickly and only have a fraction of the pit exposed at any given time. This will minimize long-term visual impacts and allow for substantial restoration of pre-project land uses by wildlife.
In 2019, we entered into a mine design, consulting and mine operations agreement with Sawtooth Mining, a subsidiary of North American Coal. Sawtooth Mining has exclusive responsibility for the design, construction, operation, maintenance, and mining and mine closure services for Thacker Pass.
North American Coal has over 60 years of surface mining experience and manages reclamation for over 200,000 acres under regulatory permits. Their extensive reclamation history has earned them over 94 federal and state awards in the last 30 years, which includes reclaiming 61,000 acres of land, reconstructing over 54.5 miles of streams and over 1,449 acres of wetlands and planting over 8.8 million trees.

The production process is designed to use conventional and commonly-available equipment, arranged to take advantage of the distinctive qualities of the high-grade ore.  The process comprises a series of steps to concentrate, separate and produce battery- quality lithium chemicals.
First, ore from the mine will be crushed, screened and then transferred as a slurry to the leaching circuit where sulfuric acid will be added to attack the ore and liberate the lithium from the clay. The high-grade quality of the ore allows for leaching to occur in stirred reactors (vats), specifically designed to maximize speed and efficiency of lithium dissolution, while minimizing sulfuric acid consumption. Total leaching time is estimated at three hours.
The resulting lithium-bearing solution will then go through a pH-neutralization step. Neutralization will be achieved with ground limestone during start-up and sustained with recycled alkaline solids from an upstream precipitation process during normal operation. Next, the lithium solution will undergo a crystallization step using steam and electricity from the sulfuric acid production process. Water is removed for recycling, and magnesium sulfate (Epsom salt) is produced. Any magnesium remaining in solution is removed in a second step that involves the addition of reagents to precipitate magnesium hydroxide.
Finally, soda ash will be added to the lithium bearing solution to produce a high-quality, battery-grade Li₂CO₃. Much of the water contained in the lithium solution will be recovered and returned to the process.  The total time projected to manufacture battery- quality Li2CO3 from the ore is less than 24 hours.

We remain committed to engaging with key stakeholders throughout the lifecycle of our projects to better understand and address their interests and concerns, and to advance our shared priorities. We continue to collaboratively work with the Fort McDermitt Paiute and Shoshone Tribe (the "Tribe") and communities closest to Thacker Pass towards mutually beneficial relationships.

Thacker Pass was designed reflecting information collected during numerous stakeholder meetings, including public open houses and ongoing engagement. This approach is expected to mitigate potential concerns at the design level, and ensures the local community is included early in the development process.

We began early engagement with the Tribe, who are located approximately 40 miles away and the largest Native American community within the vicinity of Thacker Pass. We have formed long-term relationships with Tribal members and have encouraged members to consider future employment at Thacker Pass. In October 2022, Lithium Americas and the Tribe entered a Community Benefits Agreement to establish a framework for continued collaboration and to define the long-term benefits for the Tribe.

In 2019, a Cultural Technical Report was completed, providing a cultural-resource inventory covering approximately 13,000 acres of land in the vicinity of Thacker Pass and lays the foundation for cultural-mitigation work. In late 2021 and early 2022, we arranged for specialized cultural monitor training for Tribe members. Pursuant to an Archaeological Resources Protection Act Permit issued by the Bureau of Land Management, the cultural work was completed between April to July 2022. Eleven Tribe members were hired to work in collaboration with Far Western Anthropological Research Group to ensure strict standards were followed, and Native American interests were respected during the archeological mitigation work. The cultural work found no areas of archeological significance at the Project.

We actively participate in the locally based Negotiating Work Group along with select members of the local Thacker Pass Concerned Citizens Group (TPCCG), dedicated to developing agreements - supported by scientific data and community views - to guide the construction and operation of Thacker Pass, with a focus on identifying solutions that protect the safety and wellbeing of community members.

We are committed to employing locally and working with local service providers to the greatest extent possible. We pay wages competitive to other Nevada-based mines, in order to attract and retain quality employees, and provide high standards of living. We have surveyed the qualifications of community members to better understand the current labour available.

We have partnered with Northeastern Nevada Regional Development Authority, Great Basin College, JOIN Inc., Cashman Equipment Winnemucca and Nevada Builders Alliance to leverage local resources and build capacity in the regional workforce.

Looking ahead as we start construction, our focus will be around additional job-ready training and employment opportunities, and support for cultural education and preservation. Furthermore, we have agreed to build a community center for the Tribe that includes a daycare, preschool, playground, cultural facility and communal greenhouse to support reclamation efforts and provide income for the Tribe.

As a responsible steward of the environment, we are focused on reducing our energy consumption and our priority is to sustainably manage water resources by limiting its use and safeguarding its quality. Thacker Pass has been engineered to minimize the environmental footprint, by avoiding sensitive environmental habitat and employing the best available environmental control technologies.

Over a seven-year period, we collected baseline environmental data required for the National Environmental Policy Act (NEPA) process and have developed comprehensive plans to mitigate impacts to wildlife, water and air. Extensive monitoring will be conducted during operations.

Thacker Pass is being designed for low-water consumption, heavily relying on water recycling to meet its needs. We are designing the operation as a Zero Liquid Discharge facility, which is intended to prevent the discharge of industrial wastewater into the environment. This is an extensive commitment because it means all water that is filtered from tailings must be evaporated or recycled for reuse within the site’s production process. Any water drawn will be reused and recycled an average of 7 times within the production process.

Thacker Pass’ energy strategy relies significantly on the self-generation of carbon-free energy through waste heat capture at the proposed sulfuric acid plant (“SAP”). This is expected to generate approximately 40 MW of electricity annually during Phase 1 and an additional 40 MW in Phase 2. Benefits of the co-located SAP include a reduction of Scope 1 and Scope 2 carbon emission intensity per tonne of lithium carbonate produced and eliminating the need to truck sulfuric acid to site, which should reduce the number of transports to site by approximately two-thirds (Scope 3 carbon emissions). As a result, the projected Scope 1 and 2 emission intensity for Thacker Pass is expected to be comparable to South American-based lithium brine operations and substantially lower than Australian-based spodumene operations. The Company is working towards baselining projected Scope 3 emissions

We established the Great Basin Sagebrush Restoration Fund in 2017 with the University of Nevada, Reno to develop technologies that improve desert restoration so we will be better equipped to reclaim the land concurrently during mining. In fact, the coated seed technology developed through our funding is now being commercialized for others to use. More information about the Sagebrush Restoration Fund can be found here

https://naes.unr.edu/rangeland_ecology/great-basin-sagebrush-restoration-fund/

By entering into agreements with two ranchers to utilize the State of Nevada Conservation Credit System, we’ve mitigated any potential indirect impacts to Sage Grouse, even though studies completed to date do not anticipate direct or indirect impacts to Sage Grouse

Lithium Americas achieved a key milestone with the receipt of a Record of Decision (ROD) from the US Department of the Interior Bureau of Land Management (BLM) on January 15, 2021. The ROD represents the final federal permit for the Thacker Pass Project. In February 2021, claims were filed against the BLM to appeal the issuance of the ROD for Thacker Pass. In February 2023, the Federal Court ruled favorably for the Company by declining to vacate the ROD. .The Federal Court ordered the BLM to consider one issue under the mining law relating to the area designated for waste storage and tailings which is not expected to impact the overall construction timeline.

Cultural work on approximately 13,000 acres at Thacker Pass was successfully completed in Q3 2022 with no archeological significant areas identified.

In February 2022, the Nevada Department of Environmental Protection ("NDEP") issued the final state-level permits required to commence construction: Water Pollution Control Permit, Class II Air Quality Operating Permit and Exploration and Mine Reclamation Permits.