Mining Intelligence and News
United States

Angel Island (Clayton Valley) Project

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Overview

Mine TypeOpen Pit
StagePermitting
Commodities
  • Lithium
Mining Method
  • Truck & Shovel / Loader
Mine Life... Lock
SnapshotAngel Island is among the few advanced lithium projects in the United States designed to deliver an end-to-end process for producing battery-grade lithium carbonate (Li2CO3), addressing the growing demand in electric vehicles and energy storage. Located in Nevada, this large-scale project has a three-phase production plan validated in Century’s Feasibility Study, completed in April 2024. Phase 1 will process 7,500 t/d of mill feed, with expansions to 15,000 t/d in Phase 2 and 22,500 t/d in Phase 3, generating positive cash flows throughout.

Century is actively progressing toward securing permits for Angel Island. In Q3 2024, all required baseline environmental reports were submitted for review, enabling preparation of a Plan of Operations to initiate the NEPA process. Concurrently, the company engaged experts to address key state permits, focusing on water and air quality, aligning the permitting process with project milestones.

Owners

SourceSource
CompanyInterestOwnership
Century Lithium Corp. 100 % Indirect
The claims of Angel Island Project are held 100% by Cypress

Holdings (Nevada) Ltd, a wholly owned subsidiary of Century Lithium Corp.

Contractors

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Deposit type

  • Sedimentary

Summary:

Project Geology
The western portion of the project area is dominated by the uplifted basement rocks of Angel Island which consist of metavolcanic and clastic rocks, and colluvium. The southern and eastern portions are dominated by uplifted, lacustrine sedimentary units of the Esmeralda Formation. Within the project area, the Esmeralda Formation is comprised of fine grained sedimentary and tuffaceous units, with some occasionally pronounced local undulation and minor faulting. Elevated lithium concentrations, generally greater than 600 ppm, are encountered in the local sedimentary units of the Esmeralda Formation from surface to at least 142 meters below surface grade (mbsg). The lithium-bearing sediments primarily occur as silica-rich, moderately calcareous, interbedded tuffaceous mudstone, claystone, and siltstone.

Deposit Types
The Clayton Valley deposit is reasonably well represented by the United States Geological Survey preliminary deposit model, which describes the most readily ascertainable attributes of such deposits as lightcolored, ash-rich, lacustrine rocks containing swelling clays, occurring within hydrologically closed basins with some abundance of proximal silicic volcanic rocks. The geometry of the Clayton Valley deposit is roughly tabular, with the lithium concentrated in gently dipping, locally undulating, sedimentary strata of the Esmeralda Formation. The sedimentary units are interbedded silica-rich, ash-rich mudstone and claystone, with interbeds of sandy and tuffaceous mudstone/siltstone and occasional poorly cemented silt and sandstone. The lithium concentrations are highest within the mudstone and claystone, but lithium is still also present in a siltstone unit underlying the claystone.

The deposition of the lithium-rich sediments likely occurred late in the history of the associated paleo brine lake, based largely on the stratigraphic position of the mudstone and claystone above the thick overall sandstone- and siltstone-dominated basin fill events. Such a setting would be ideal for the concentration of lithium from ash and groundwater inputs over an extensive period. As a result, the lithium-rich strata may represent several million years of lithium input and concentration within the basin. Figure 8-1 through Figure 8-3 show a conceptual sequence of depositional, erosional, and structural events which may account for the present-day nature and occurrence of the lithium deposits.

Within the lithium-bearing sediments of the deposit are oxidation and unaltered horizons that are recognizable in drill cores. Based on the drilling to date, the highest lithium concentrations occur within claystone zone 2 which has a central unaltered zone inter-layered between two oxidized layers. This distribution of mineralization may be the result of recent, oxidizing surface waters penetrating down dip within more permeable beds of the sedimentary package to create a series of oxidation-unaltered layers.

Mineralization
Elevated lithium concentrations, generally > 600 ppm, are encountered in the local sedimentary units of the Esmeralda Formation from surface to at least 142 mbsg. The lithium-bearing sediments primarily occur as silica-rich, moderately calcareous, interbedded tuffaceous mudstone, claystone, and siltstone. The overall mineralized sedimentary suite is a laterally and vertically extensive, roughly tabular zone with at least two prominent oxidation horizons (Figure 7-4). The primary area of mineralization is in a claystone unit consisting of three zones: oxidized claystone, unaltered claystone, and an oxidized claystone. The claystone unit is overlain by tuffaceous mudstone in the eastern portion of the project and underlain by a siltstone. Elevated lithium concentrations occur in all the uplifted lacustrine strata encountered; however, lithium concentrations are notably higher and more consistent in the claystone unit.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

CommodityProductUnitsAvg. AnnualLOM
Lithium Carbonate kt 341,393
Sodium hydroxide kt 12,557

Operational metrics

Metrics
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Ore tonnes mined, LOM  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2024 study.

Production Costs

CommodityUnitsAverage
Cash costs Li2CO3 USD  ....  Subscribe
Cash costs Li2CO3 USD  ....  Subscribe
Assumed price Sodium hydroxide USD  ....  Subscribe
Assumed price Li2CO3 USD  ....  Subscribe
* According to 2024 study / presentation.
** Net of By-Product.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M USD  ......  Subscribe
Expansion CapEx $M USD  ......  Subscribe
Working capital $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
Total OpEx $M USD  ......  Subscribe
Income Taxes $M USD  ......  Subscribe
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Royalty payments $M USD  ......  Subscribe
Net revenue (LOM) $M USD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax NPV @ 8% $M USD  ......  Subscribe
After-tax IRR, %  ......  Subscribe
After-tax payback period, years  ......  Subscribe

Required Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Apr 29, 2024
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Aerial view:

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