Copperstone
Gold stream on Copperstone Gold Mine – a previously producing, construction-stage mine in Arizona
Operator
Sabre Gold Mines Corp. (pending proposed acquisition by Minera Alamos announced Oct. 28, 2024)
Location
Arizona, USA
Stage
Construction-ready
Commodity
Gold
Terms
Gold Stream of 4% of Au produced for the duration of Copperstone’s Life-of-Mine (“LOM”).
Cash payment per ounce of gold delivered equal to 25% of the average LBMA gold spot price.
Purchase Price
US$12 million in two US$6 million tranches.
In November 2023, the stream was revised from a previous 6.6% of gold production with production-based stepdowns to a flat 4% gold stream for the duration of Copperstone’s LOM and C$4.55 million in combination of cash and shares. Please see the November 2, 2023 press release detailing the restructuring.
Highlights
- Near-term production: On October 28, 2024, Minera Alamos announced a proposed acquisition of Sabre Gold and indicated its intent to accelerate Copperstone into production by already initiating engineering efforts aimed at fast-tracking Copperstone’s development, engaging with lenders regarding finance facilities, as well as expanding its technical team. Copperstone’s permits are in place for the restart of mining operations and Minera Alamos anticipates a 12-month construction schedule from a construction decision.
- Tier 1 jurisdiction in Arizona, USA: The mine restart plan envisions an approximately 550 tonne-per-day underground operation and whole ore leach process to produce gold doré on site.
- Low capital intensity restart: Fully permitted asset with significant (+US$100 million) infrastructure in place.
- Historical producer: Copperstone historically produced over 500,000 ounces from 1987 to 1993 through open-pit mining, and was acquired by Sabre Gold in 2014.
- Expansion potential and exploration upside: The February 2023 Mineral Resources Estimate contains 300,000 ounces in Measured and Indicated Resources and 197,000 ounces in Inferred Resources. Sabre Gold has identified multiple high-priority drill targets and highlights over 1 million ounces of near-mine resource potential at Copperstone that could lead to an eventual mine life extension.
Asset Description
Copperstone is a past-producing gold mine located in western Arizona, USA, approximately 230 km west of Phoenix and has year-round access. The project sits within the Walker Lane gold trend, a mineral belt hosting a total known gold endowment of over 40 million ounces.
The Copperstone Project is presently under construction and re-development as an underground operation. Over 500,000 ounces were produced from 1987 to 1993 by Cyprus Minerals via open pit methods. Sabre Gold estimates that over US$100 million in mining and processing infrastructure remain in place at Copperstone allowing for relatively modest restart capital costs.
Sabre Gold’s recently updated Mineral Resources Estimate at Copperstone contains Measured & Indicated Resources of 300,000 ounces (1,207,000 tonnes at 7.74 g/t), and Inferred Resources of 197,000 ounces (970,000 tonnes at 6.3 g/t). The updated mineral resource statement and a recent Preliminary Economic Assessment (June 2023) support Star Royalties’ investment case by demonstrating potential for additional growth in resources and future mine life extension.
The mine and process plant are forecast to run at a rate of 550 tonnes per day, with all mineralized material being crushed, milled and processed by whole ore leach (direct cyanidation of Copperstone’s entire ore feed and production to doré). Gold recoveries are expected to average 95%. The mining method is expected to be predominantly mechanized cut-and-fill using rock fill and cemented rock fill with an average dilution assumption of 25.3%. Annual gold production is expected to be approximately 40,000 ounces, with average all-in sustaining costs of ~US$1,290/oz, according to Sabre Gold.
