Mining Intelligence and News
United States

Rhyolite Ridge Project

Click for more information

Categories

Overview

Mine TypeOpen Pit
StagePermitting
Commodities
  • Lithium
  • Boron
Mining Method
  • Truck & Shovel / Loader
Mine Life... Lock
SnapshotAs announced on 15 April 2024 the draft Environmental Impact Statement (DEIS) for the Rhyolite Ridge Project was made public by the Federal Bureau of Land Management (BLM) and was published in the Federal Register on 19 April 2024. A 45- calendar day public comment period commenced on that date.

Following the receipt of input provided during the public comment period a Final Environment Impact Statement (FEIS) will be prepared by the BLM contractor, intended to lead to final approval of the FEIS by the BLM through the issue of a Record of Decision (ROD).

The completion of the National Environmental Policy Act (NEPA) permitting process will then be reflected in the approval by the BLM of the Project's Plan of Operations (Plan) through the ROD, allowing construction of the Project to commence and providing the permitting framework for production at the site.

Owners

SourceSource
CompanyInterestOwnership
Ioneer Ltd. 100 % Indirect
IONEER Limited of Australia is the parent company to both IONEER USA Corp. and IONEER Minerals Corp., collectively referred to as IONEER. The operator of the Rhyolite Ridge Project is IONEER USA Corp., a Nevada (U.S.) company. Title to the Rhyolite Ridge mining claims are held by IONEER Minerals Corp. and IONEER USA Corp., which together own 263 unpatented mining claims comprising the project area.

16 September, 2021 – ioneer Ltd (“ioneer” or the “Company”) (ASX: INR) is pleased to announce that the Company has reached an agreement to establish a joint venture (the “Joint Venture”) with Sibanye Stillwater Limited (“Sibanye-Stillwater”) to develop the flagship Rhyolite Ridge Lithium-Boron Project located in Nevada, USA (the “Project”). Under the terms of the agreement, Sibanye-Stillwater will contribute US$490 million for a 50% interest in the Joint Venture, with ioneer to maintain a 50% interest and retain operatorship.

Contractors

Lock

- subscription is required.

Deposit type

  • Sediment-hosted

Summary:

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 6 kilometers by 2 kilometers and covers an area of 800 hectares.

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. The lacustrine (lake) beds that host the mineralization lie within the Cave Spring Formation and overlie the 6-million-year-old Rhyolite Ridge Tuff and Argentite Canyon volcanic rocks. The lacustrine section that measures up to 457 meters thick is composed of three members, divided by marker beds of “gritstone” comprised of airfall debris with abundant pumice lapilli. The middle member, which is bounded top and bottom by distinctive gritstones, is dominantly marl, composing nearly 60 meters of section, and bears anomalous lithium in its upper half. About 18 meters of this section contains high concentrations of boron –contained in the sodium borosilicate mineral, searlesite (up to 30,000 parts per million [ppm] boron) – as well as lithium in mixed illite-smectite layers (about 1,500 to 2,500 ppm lithium). This marl is composed of very fine grained, intimately mingled searlesite, smectite, illite, potassium feldspar, and carbonate. The searlesite zone is capped by about 12 meters of smectite-rich marl with relatively high lithium values (commonly 2,000 to 2,500 ppm). The grade and thickness of this middle member are laterally uniform and continuous over a distance of at least 3 kilometers north to south.

The Cave Spring Formation hosts the ore zones of interest for the project, designated as follows:
- M5 – 13-meter-thick lithium claystone layer to be removed and separately stockpiled for possible future processing.
- B5 – 18-meter-thick upper ore zone of high-grade lithium-boron ore making up most of the ore planned for extraction.
- L6 – 40-meter-thick lower ore zone of lower-grade lithium-boron ore zone.

Underlying layer are sedimentary and volcanic rocks of the Silver Peak Formation.

Reserves

Lock

- subscription is required.

Mining Methods

Lock

- subscription is required.

Comminution

Crushers and Mills

Lock

- subscription is required.

Processing

Lock

- subscription is required.

Production

Lithium hydroxide (99.5%): 21,951 tpa (conversion of lithium carbonate in years 4 to 26).
CommodityProductUnitsAvg. AnnualLOM
LCE t 496,700
Lithium Hydroxide t 21,951
Li2CO3 t 20,588
Boric acid Crystals t 174,348
Sulphuric acid t 3,502

Operational metrics

Metrics
Daily processing rate  ....  Subscribe
Annual ore mining rate  ....  Subscribe
Annual processing rate  ....  Subscribe
Stripping / waste ratio  ....  Subscribe
Ore tonnes mined, LOM  ....  Subscribe
Total tonnes mined, LOM  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2020 study.

Production Costs

CommodityUnitsAverage
All-in sustaining costs (AISC) LCE USD  ....  Subscribe
Assumed price Boric acid USD  ....  Subscribe
Assumed price LiOH USD  ....  Subscribe
Assumed price Li2CO3 USD  ....  Subscribe
* According to 2020 study / presentation.
** Net of By-Product.

Operating Costs

Currency2020
OP mining costs ($/t milled) USD 4.04 *  
Total operating costs ($/t milled) USD  ....  Subscribe
* According to 2020 study.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Closure costs $M USD  ......  Subscribe
OP OpEx $M USD  ......  Subscribe
Processing OpEx $M USD 2,668
Total OpEx $M USD  ......  Subscribe
Gross revenue (LOM) $M USD  ......  Subscribe
Operating margin, %  ......  Subscribe
EBITDA (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax NPV @ 10% $M USD  ......  Subscribe
After-tax NPV @ 8% $M USD  ......  Subscribe
After-tax IRR, %  ......  Subscribe

Required Heavy Mobile Equipment

Lock

- subscription is required.


AV - Autonomous

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2024

Total WorkforceYear
...... Subscription required 2020

Lock

- subscription is required.