Project AspectProject IconProject Aspect Description
NEVADA JOBSNevada JobsEmploying 250-300 people while mine operates and 400-500 people during the construction period with median total compensation levels of ~$141,000/year*
NEVADA SUPPLIER OF CRITICAL MINERALSCritical MineralsProducing ~24,000 tons per year of Lithium Carbonate /Hydroxide and ~192,000 tons per year of Boric Acid
STATE AND LOCAL PUBLIC REVENUE IMPACTPublic Revenue ImpactConstruction period impact of $15MM-25MM and Operating period annual impact of $13MM–31.5MM*
LOW WATER USAGELow Water UsageAbout 3,550 acre-ft/year- similar usage to 7 pivots irrigating 840 acres, no evaporation ponds
SMALL FOOTPRINTSmall FootprintNo evaporation ponds, no tailings dam. Plan of Operations mine footprint of approximately 931 acres
LOW EMISSIONSLow EmissionsMajority of on-site power will be met with CO2-free energy production, low greenhouse gas emissions
ROAD IMPROVEMENTSRoad ImprovementsResponsible for maintenance and improvements for road from Highway 264 to the facility

*Applied Analysis Economic Impact Study, April 2020, Low-High Case Range


The Rhyolite Ridge Lithium-Boron Project is located in Esmeralda County, Nevada, on public land administered by the U.S. Department of Interior’s Bureau of Land Management (BLM) within the Silver Peak Range.

Rhyolite Ridge Location

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Project Location

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Average Commute Times from RR

Rhyolite Ridge is approximately 14 miles northeast from Dyer, Nevada (nearest town); 65 miles southwest of Tonopah, Nevada (closest city); 215 miles from Reno (third largest city in Nevada); and 255 miles from Las Vegas (largest city in Nevada). Average commute times to Rhyolite Ridge from nearby communities are noted in the image to the left. Surface elevations at the project site range from 5,535 to 6,010 feet (1,687 to 1,832 meters) above sea level.

Community Engagement

Ioneer is committed to making a positive impact on the global environment and that starts with the support of the local community. For many years we have solicited feedback and provided updates to the community on a regular basis as the project has progressed. We also have worked closely with regulators regarding the socio-economic studies required for permitting projects on land administered by the BLM.

Ioneer continues to provide information and solicit feedback by:

  • Providing regular presentations to regional County Commissions
  • Holding In-person community meetings
  • Collaborating with local Tribal Nations to understand their interests and priorities, while facilitating partnerships so they too can maximize the benefits of the transition to a clean energy economy
  • Providing updates in Local Newspapers
  • Publication of a Quarterly Newsletter oriented towards the communities near the Project
  • Being an active participant in the Esmeralda County Land Use Advisory Committee – a body formed by the Esmeralda County Commission to review and make suggestions to update the County’s Master Plan. We have provided information relating to the Project’s economic impacts to the region so the Committee can make appropriate recommendations for changes in the Master Plan

The Rhyolite Ridge Project will generate considerable economic impact within the regional community by generating millions of dollars in revenues for local governments and the state of Nevada, while creating jobs both from direct employment and through local businesses that will provide products and services at Rhyolite Ridge.


In April 2020, Applied Analysis issued an economic impact study related to the Rhyolite Ridge Project.
Key findings from the study are detailed below.


  • Construction of the Rhyolite Ridge Project is expected to take two years. The combined value of all spending as a result of the project’s construction (i.e., economic output) is estimated to range from $68 million to $217 million.
  • Given direct and indirect economic benefits of the project, for every dollar spent in the local economy on the development of the Project, a total of $1.99 in economic activity benefits the community as a whole.
  • Over the expected construction period, using a median case scenario Applied Analysis calculates the creation of 946 person-years of employment, or about 473 construction jobs per year. This will result in over $60 million in wages and salaries, and an overall economic output of over $130 million.


  • Once the Rhyolite Ridge project is operational, the same study projects that Rhyolite Ridge will directly employ 284 persons per year, for a total of nearly $40 million dollars in annual wages (average total compensation of $140,727 per job).
  • Additionally, nearly 681 indirect jobs are projected to be supported through purchases of supplies for the project, generating an additional $40.9 million in annual wages.
  • Further, local spending from both direct and indirect employees is expected to support an additional 381 jobs per year across the region.


  • During the construction phase of Rhyolite Ridge, the Applied Analysis report projects that the Project will contribute approximately $22.5 million in sales and use taxes to benefit local and state governments using its median case assumptions.
  • Once in operation, the Project will generate approximately $22 million annually in fiscal revenue for state and local governments through 1) Nevada net proceeds of minerals taxes, 2) sales and use taxes, 3) property taxes, 4) modified business taxes, 5) commerce taxes and 6) regulatory fees. This estimate is also calculated by Applied Analysis using its median case assumptions.


  • The investment by Ioneer in the local community goes beyond jobs and broader economic impact: we have been, and plan to continue to be an active participant in the community by supporting local causes. This includes the annual Ioneer Sustainable World Scholarship – which is awarded to local High School graduates pursuing higher education in Engineering, Science and/or Mining.
  • Total charitable investments in the community are expected to range between $100,000 and $250,000 during operations.

Regional Geology

The Rhyolite Ridge Project site is situated in the Silver Peak Range, part of the larger geo-physiographic Basin and Range Province of western Nevada. Horst and graben normal faulting is the dominant characteristic of the Basin and Range Province, which is believed to have occurred in conjunction with large-scale deformation due to lateral shear stress. This is evidenced in the disruption of large-scale topographic features throughout the area. The project area sits within the Walker Lane Fault System, a northwest trending belt of right-lateral strike slip faults.

Rhyolite Ridge is a geologically unique lithium-boron deposit that occurs within lacustrine sedimentary rocks of the South Basin, peripheral to the Silver Peak Caldera. The South Basin within the project boundaries measures 4 miles by 1 mile and covers an area of just under 2,000 acres.

The regional geology is characterized by relatively young Tertiary volcanic rocks thought to be extruded from the Silver Peak Caldera, which date to approximately 6.1 million to 4.8 million years old. The northern edge of the Silver Peak Caldera is exposed approximately 2 miles to the south of the South Basin area and is roughly 4 miles by 8 miles in size. The Tertiary rocks are characterized by a series of interlayered sedimentary and volcanic rocks, which were deposited throughout west-central Nevada. These rocks unconformably overlie folded and faulted metasedimentary basement rocks that range from the Precambrian through Paleozoic periods.

Rhyolite Ridge is one of only two major lithium-boron deposits globally and the only known deposit associated with the boron mineral searlesite. This mineralization style is different to the brine and pegmatite deposits that are the source of nearly all the lithium produced today and is also unlike lithium-claystone deposits found in the region.

The laterally continuous sediments of Cave Spring form distinctive units and are found outcropping at surface as well as at depths of up to 1000 feet. Interbeds of siltstones, claystones and carbonate units characterize the formation and pumice-rich volcano-sedimentary units called gritstones form pervasive marker beds.

The 6 million-year-old basement rocks – Rhyolite Ridge Tuff and Argentite Canyon Latite – represent the early stages of volcanic activity for the Silver Peak Caldera. The caldera, with activity spanning 1 million years, injected volcanic glass, rhyolite and ash into a spring-fed closed basin, depositing the Cave Spring Formation.

The highly competent 65-foot-thick ore zone, formed by diagenesis of volcanic sediments deposited in an alkaline lake, is characterized by very fine boron-rich searlesite crystals (up to 30,000 parts per million (ppm) boron) and lithium in illite-smectite layers (about 1,500-2,500 ppm lithium).


Click map to enlarge.

The overall site plan for the Rhyolite Ridge Project is shown to the left. The compact project site extends from the mine quarry in the east to the processing facilities and spent ore storage facility in the west. The processing facilities are approximately 1.8 miles northwest of the quarry and 1 mile north of the spent ore storage facility.

The mining operations will consist of a conventional drill-and-blast, load-and-haul operation. Ore will be trucked from the mine quarry to the nearby ore processing plant over a new heavy duty haul road.


We have expended considerable effort to develop a safe and economically viable Project while avoiding
and/or minimizing potential impacts to environmentally sensitive areas.

As a result of ongoing consultation with federal regulators, Ioneer submitted a revised Plan of Operations for the Project in July, 2022. A partial list of these revisions are below:

  • Quarry Modification – no longer calls for translocation of Buckwheat from any subpopulation, resulting in no direct impact to any buckwheat plant
  • Development of in-quarry overburden storage to minimize ground disturbance and improve stability
  • Adoption of site-tailored mining techniques to maintain stable quarry walls
  • Implementation of closure plans to provide long term stability once mining is completed
  • Fencing around each buckwheat population
  • Construction of North Overburden Storage Facility – located away from buckwheat populations
  • Revision of West Overburden Storage Facility to avoid buckwheat and other sensitive resources
  • Weed and Invasive Species control activities will be limited to methods approved by BLM and USFWS
  • Enhancing design of Spent Ore Storage Facility as a “dry facility” with liners, seepage collection systems, and leak detection systems to collect and manage contact water.

Ioneer will capitalize on new advancements in mining technology to enhance project performance including haul truck automation, semi-autonomous dozing and drilling, and fully autonomous drones for mine advancement surveys.

In September of 2022, Ioneer announced the completion of a Technology System Supply Agreement with Caterpillar, the world’s largest manufacturer of construction and mining equipment. This definitive agreement builds upon the Memorandum of Understanding signed in 2021 and solidifies the early introduction of Cat® MineStarTM Command for hauling, Autonomous Haul System (AHS) at the Rhyolite Ridge Project.

To date, Cat autonomous mining trucks have safely hauled more than 2 billion tons of material worldwide, driving over 42 million miles.



The vat leaching process uses a series of 7 vats where crushed ore is sequentially leached for 3 days with diluted sulfuric acid. The vats operate in a counter-current configuration, made possible by the unique Rhyolite Ridge ore particles remaining largely intact and free-draining during the leach process. Counter-current leaching minimizes the overall leaching time and acid consumption. The spent ore undergoes a displacement wash to remove valuable interstitial lithium and boron in solution. The spent ore is free draining, allowing the vat to be emptied of solution producing a residue material that is suitable for dry stacking. High lithium and boron recoveries in leaching are consistently achieved at low to moderate temperatures (60°C) and moderate free-acidity levels.


Crystallization of boric acid is achieved by cooling the vat leach solution (referred to as pregnant leach solution (PLS). Since the PLS is close to saturation in boric acid, the cooling effect in the crystallizer produces boric acid crystals. The boric acid crystals are separated using centrifuges and then undergo a second-stage recrystallization for purification. Most of the boric acid is recovered with minimal contamination from sulphate salts.


The main evaporation and crystallization circuit is designed to concentrate lithium and remove sulphate salts and other impurities. The solution (mother liquor) from the boric acid crystallization undergoes impurity removal of aluminum and other elements and is then pumped to a 4-stage evaporator circuit to remove 70% contained water and concentrate the lithium. Water vapor from the evaporators is condensed and reused throughout the process. This evaporation and crystallization process is critical to the concentration of the lithium to a high-level suitable for the lithium carbonate circuit.


A 3,858 tons per day sulfuric acid plant will produce commercial-grade (98.5%) sulfuric acid for vat leaching of the lithium ore, steam to drive the evaporation and crystallization circuit, and electricity to drive the entire process. The plant will generate 35 MW of electricity – sufficient to run the entire facility and will be separate from the Nevada state power grid. The selection of the technology for the large sulfuric acid plant is based on a proven operating design and specialty technology provider (MECS-DuPont). The acid plant is a double conversion-double absorption system that has proven to be reliable and predictable. It includes a tail gas scrubber system that results in ultra-low emissions (12 ppm SO2 and 15 ppm NOx).


The lithium carbonate circuit is designed to produce technical-grade lithium carbonate from the lithium brine mother liquor. Lithium carbonate is precipitated from the mother liquor using soda ash. The precipitated lithium carbonate is filtered, washed, and dried. The lithium carbonate produced can be sold as a technical-grade (99.0%) product or with additional processing can be converted into lithium hydroxide (99.5%). For the first 3 years, we currently expect that lithium carbonate will be sold as technical-grade.


The Rhyolite Ridge process flowsheet demonstrates a strong synergy for the installation of an onsite lithium hydroxide circuit. Installation of the circuit is currently planned for year 3 of operations, allowing the main plant to be operating smoothly before the addition. The conversion of Rhyolite Ridge technical-grade lithium carbonate to battery-grade lithium hydroxide will be achieved by the liming method and further utilize the electricity generated by the sulphuric acid plant.


Ioneer is committed to providing a safe, injury-free work site while protecting the environment and surrounding communities.

A site health, safety, environmental (HSE) and security program will be developed before construction commences, and will transitioned once the operations phase begins. The program will meet or exceed mandatory codes, acts, and regulatory requirements of MSHA of the U.S. Department of Labor. The HSE program will include safety requirements addressing hazardous processes, hazardous materials and equipment, fire suppression equipment, safe work permit requirements, emergency procedures, safety training requirements, incident reporting, and medical services support.

The message that safety is a core value will be communicated to all levels of the project’s organization and workforce. The HSE plan will describe the project’s core values and policy for complying with all relevant HSE commitments, laws, and regulations. Training for employees will include a comprehensive overview of expectations for safe execution of work activities on the project. This training will include instructions on how all project employees, contractors, and other personnel are to perform their duties and comply with MSHA regulations.

Key Emergency Response Roles at Rhyolite Ridge will include:

  • Emergency Medical Technician – Ioneer will employ a certified Emergency Medical Technician (EMT) to handle all minor incidents on-site. The EMT will be located at the medical clinic near the administration building during day shift.
  • First Aid Responders – Ioneer will ensure that at least one individual capable of providing first aid is available on all shifts.
  • Fire Brigade – Individuals across the Project site will receive specialized fire-fighting training in areas with special materials or higher fire potential, and will also be equipped and trained to respond to any wildland fire that may occur near the Project.
  • Emergency Safety Warden – Each department/work team will have an emergency safety warden who will be trained and certified to know what to do in the case of an emergency.
  • An on-site ambulance and trained first aid responder will be available to respond to fire and medical emergencies at the site 24 hours per day, seven days per week. Additionally, an EMT will be staffed onsite during day shift at the medical clinic located near the administration building.

Further, Ioneer continues to work collaboratively with local emergency response personnel to coordinate how these entities and Ioneer will work together to quickly and effectively respond to any major incidents.