The Gold Bar property is located on patented lands and public lands managed by the Bureau of Land Management (BLM) Battle Mountain Field Office. McEwen Mining has been pursuing building the Gold Bar mine since 2013. A signed Record of Decision on the Final Environmental Impact Statement published by BLM in November 2017 marked the completion of the National Environmental Protection Act process. Gold Bar was the first new gold mine in Nevada to gain permit approval in several years.
Following obtaining the permit approval, a property-wide exploration program was designed to extend the life of the mine by expanding the mineral inventory surrounding the planned open pits and testing new targets on the property.
Exploration delivered encouraging results, through initial drilling focused on three areas: northwest of the planned Pick open pit, northwest of the planned Ridge open pit, and in-between Pick and Ridge. A new shallow oxide mineralization zone has been identified in Hole GB257, which returned 1.4 gpt gold over 16.8 m, starting at a depth of 9 m. Holes that encountered significant mineralization had a weighted average grade and thickness of 1 gpt gold over 15.2 m.
In February 2018 a feasibility study was completed, with changes to the implementation strategy for the Gold Bar mine, such as the addition of a crushing, conveying and agglomeration plant and changes in heap leach pad construction, made with the goal of reducing overall project risk and maintaining high capital efficiency.
Acquired by McEwen Mining in 2016, Gold Bar South is a property that consists of 109 mining claims, located approximately 3.5 miles (5.5 kilometers) southeast of our Gold Bar mine, and that hosts a near surface oxide gold deposit. An infill and pit definition drilling program conducted in 2019 at Gold Bar South had 25% of the new drill intersections showing gold grades averaging above 1 gpt. New mineralized structures were identified outside the existing resource, including notable gold intersections such as 6.66 gpt over 24 m, 2.13 gpt over 55 m and 2.21 gpt over 51.8 m (for more results see press releases from Aug 20, 2019
and Oct 15, 2019).
Drilling has encountered an area between the NE and NW trending faults of higher-grade oxide mineralization of over 2 gpt gold, measured at 50 m wide, 50 m long and 50 m thick. Exploration drilling at Gold Bar South was continued in 2020, in order to incorporate the associated satellite pit into the mine plan.
Gold Bar reached commercial production in May, 2019.
Gold Bar produced 30,700 gold ounces in 2019, at cash costs and all-in sustaining costs of $1,101 and $1,282 per gold equivalent ounce, respectively.
The majority of the material mined at Gold Bar in 2019 was from the Cabin pits, which reconciled positively to our block model for gold grade (+18%) and negatively for ore tons (-8%), with resulting contained gold ounces at +8%. The transition in 2020 to mining from the Pick West pit has returned lower ore tons and gold grade from the upper benches as compared to the block model, due to greater structural control of the mineralization than was previously expected.
In light of the significant differences observed between the modeled (expected) and mined (actual) ore tonnage and gold grade from the Pick West pit, the resource and reserve estimates have been re-evaluated in 2020. Significant work completed at Gold Bar in 2020 to determine the difference in contained ounces and to mitigate it included a 110,500 feet (33,700 m) drilling program - 64,000 feet (19,500 m) at the Pick deposit, 35,000 feet (10,700 m) at Gold Bar South and 11,500 feet (3,500 m) at the Ridge deposit, together with additional metallurgical testing.
The Pick, Ridge, and Gold Bar South geological models and resource estimates were updated by McEwen Mining technical staff. The Cabin resource estimate was updated by Mine Technical Services. The geologic interpretations were updated to include structural modeling for all deposits and all resource estimates had independent third-party review for quality assurance. In addition, experts in the field of heap leach technology were engaged to review ore processing and recommended improvements based on test work and site observations, which include ending agglomeration, revised recovery estimates for all resources, and categorization of resources based on metallurgical attributes and clay content.
In a Jan 7, 2021 press release the Company announced an updated resource estimate of 499,000 contained gold ounces in the Indicated category and 53,000 contained gold ounces in the Inferred category and a Probable Reserve Estimate of 302,000 recoverable gold ounces for the Gold Bar Mine (resources and reserves with effective date Dec 1, 2020).
To provide perspective on the changes that occurred at Gold Bar, consider that in 2019, when we started mining, the reserve estimate was 430,000 gold ounces. Factoring in the depletion from cumulative mine production to December 2020 of 58,600 gold ounces, there was a net reserve reduction of 16% determined by changes to the geologic model, metallurgical recovery, additional drilling information, and higher gold prices.
Gold Bar's Feasibility Study update issued on Feb 22, 2021 (click here for the report) estimates an After-Tax Net Present Value discounted at 8% and using a gold price of $1,500/oz of $55.2 million; while the upside case, using a gold price of $1,900/oz, has an NPV of $125.7 million. Based on the estimated reserves, current mine life is of 6 years.
In 2021 exploration continues, based on a $5 million budget and a new understanding of the geological characteristics at Gold Bar.