Equinox Gold (TSX: EQX; NYSE: EQX) has announced an increase in reserves and resources at its Mesquite open-pit heap leach gold mine in California, 56 km east of Brawley and 84 km northwest of Yuma, Arizona.
According to the company, estimated proven and probable reserves increased by 142,267 oz. gold as of June 30, up 28% from the previous estimate in December 2019, and now stands at 37.8 million tonnes grading 0.54 gram gold per tonne for 658,000 contained oz. gold. The estimate, the company said, is net of mining depletion amounting to 68,267 oz. gold during the first half of 2020.
Measured and indicated resources are estimated at 66.7 million tonnes grading 0.39 gram gold for 837,000 oz. gold, a 94% increase from the December 2019 estimate of 432,000 ounces.
Inferred resources rose by 193,000 oz. to 69.2 million tonnes grading 0.32 gram gold for 703,000 oz. gold, a 38% increase over the same period.
The mid-year update, the company said, incorporates an additional 77 drill holes over 10,785 metres of bedrock drilling, 661 holes totalling 36,785 metres of drilling targeting historical dumps, and updated geologic and grade-shell domains.
At the end of 2019, the company had identified approximately 36 million tonnes of potentially mineralized material from previous operations that had not been drill tested and initiated a 35,000-metre exploration drill program.
Drilling in the Big Chief, Midway, and Brownie waste dumps at Mesquite yielded significant gains in mineral resources, the company reported. Indicated resources in the dumps increased more than four-fold to 22.7 million tonnes grading 0.22 gram gold for 160,000 contained oz. gold and inferred resources rose by 31% to 36.6 million tonnes grading 0.22 gram gold for 225,000 ounces. The increase did not reflect the depletion of resource material contained in the 2019 mineral resource that had already been stacked on the leach pad, the company noted.
Drilling in 2019, the company reported, confirmed that the dump material overlying the Brownie deposit area contained gold resources and that in-situ mineralization was present adjacent to and extending from the resource pit.
A follow-up 13,897-metre drill program on the Brownie deposit was undertaken to test the potential to extend mineralization along strike and down dip. Highlights include 35 metres grading 0.51 gram gold; 34 metres grading 0.66 gram gold; 53 metres grading 0.85 gram gold; and 44 metres grading 0.58 gram gold.
The results, the company said, increase its confidence in the geological model and highlight the potential for further expansion potential to the north, northwest, and southeast of existing resources.
“Exploration efforts at Mesquite in the first half of 2020 more than replaced mined reserves and significantly increased mineral resources, providing additional mine life at what has been our best-performing mine this year,” Scott Heffernan, Equinox’s executive vice president of exploration, said in a statement.
“Drilling in the Brownie deposit also yielded excellent results and points to the potential for a multi-year mine life extension from in-situ mineralization and overlying mineralized dumps.”
At press time in Toronto, Equinox was trading at C$15.62 per share within a 52-week trading range of C$6.60 and C$17.99.
The company has around 241 million common shares outstanding for a C$3.8-billion market capitalization.
(This article first appeared in The Northern Miner on October 09)