Castle Mountain Gold Mine

Producing gold in California

Castle Mountain Phase 1 operations commenced in November 2020 as a small heap leach mine while Equinox Gold permits the planned Phase 2 expansion.





California, USA

2024 Production1

30,000-35,000 oz gold

2024 Costs1

$2,125-$2,200 per oz AISC


4,168 Koz @ 0.51 g/t gold

M&I Resources2

1,470 Koz @ 0.62 g/t gold

Mining and processing

Open-pit / heap leach

Estimated mine life

~20 years (including Phase 2)

1. Guidance released on February 21, 2024.
2. M&I Mineral Resources are exclusive of Mineral Reserves. See Operations / Reserves & Resources and Cautionary Notes.


Castle Mountain is an open-pit heap leach gold mine located in San Bernardino County, California, USA, approximately 200 miles north of our Mesquite Mine and 60 miles south of Las Vegas, Nevada. Under a previous owner, Castle Mountain produced more than 1.2 million ounces of gold from 1991 to 2004, when the mine was closed due to low gold prices. 

Equinox Gold acquired Castle Mountain in December 2017 and completed a pre-feasibility study in 2018 with the intention of restarting operations. The pre-feasibility study outlined a two-phase development plan, with annual average gold production of approximately 30,000 ounces during Phase 1 using existing operating permits, and a Phase 2 expansion to more than 200,000 ounces of gold per year. 

Phase 1 construction activities commenced in October 2019 and commercial production was achieved in November 2020. The Castle Mountain team won Equinox Gold’s 2020 Chairman’s Safety Award for completing construction with no lost-time injuries. Phase 1 processes primarily stockpiled ore from previous operations and is essentially a small-scale pilot plant for the planned Phase 2 expansion. Permitting for the Phase 2 expansion commenced in March 2022; the permitting process and Phase 2 construction are anticipated to require four years.

Production at Castle Mountain in 2024 is forecast at 30,000 – 35,000 ounces of gold with all-in sustaining costs between $2,125 – $2,200 per ounce of gold sold. Costs at Castle Mountain remain elevated as a result of the transition to crushing and agglomerating all ore
to increase ore permeability and gold production. A portion of the ore under leach continues to be run-of-mine but will gradually
transition to all crushed as crusher throughput is improved. Sustaining capital of $3 million is primarily for equipment upgrades. Non-sustaining capital of $4 million is primarily for Phase 2 optimization studies, metallurgical test work and permitting.

Operating Data

 2023 Actuals2022 Actuals2021 Actuals
Gold produced (oz)20,83723,22725,270
Cash costs ($/oz)1,5311,217883
AISC ($/oz)1,8991,6991,429
Sustaining capital ($M)1114
Growth capital ($M)58

Mining and Processing

Mining is performed using owner-operated, conventional truck and shovel open-pit mining methods. While originally planned to be a standard run-of-mine operation, the Company converted to crushing and agglomeration of the ore in Q2 2022 to resolve percolation issues, with conveyor transport of crushed ore to the leach pad for stacking. Stacked ore is fully leached after approximately 90 days.

Loaded carbon from the processing circuit is hauled to the Company’s Mesquite Mine for gold extraction, eliminating the need for a dedicated elution circuit at Castle Mountain and optimizing plant capacity at Mesquite.

Exploration and Geology

Castle Mountain is located in the historic Hart Mining District, at the southern end of the Castle Mountains. The Castle Mountain project is classified as a low-sulfidation epithermal gold deposit. The Miocene-age Castle Mountains Volcanic Sequence rocks are the primary host of epithermal gold mineralization at the project. Silica alteration and iron oxide minerals generally occur with gold mineralization.

Several hundred old prospects, pits, trenches, waste rock dumps and underground workings extend over an approximate two square -mile area overlapping the project area. Three underground gold mines were in production from 1907 to 1911. A resurgence in exploration activity commenced in 1968 and Castle Mountain commenced production as a large-scale open-pit mine in 1991. Mining ceased in 2001 due to low gold prices but heap leaching continued until 2004 to recover residual gold, with more than 1.2 million ounces of gold produced from 1991 to 2004.

While significant exploration potential exists within the mine boundary, to the northeast, and to the northwest, the Company has already delineated enough Mineral Reserves to support an approximately 20-year mine life. There is mine life extension potential from the substantial Mineral Resources, although the Company does not intend to undertake any significant exploration at the property in the near term.

Castle Mountain Phase 2

Permitting is underway for the Castle Mountain Phase 2 expansion that will increase production to more than 200,000 oz of gold per year.

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