Mining Explorers 2017: Hecla Mining Co.
Hecla Mining Company has a long-running practice of replacing reserves it mines each year at the Greens Creek Mine, a tradition it continued in 2016 despite producing a record 9.3 million ounces of silver at this high-grade underground operation in Southeast Alaska. Going into 2017, Greens Creek had 7.6 million tons of proven and probable reserves averaging 11.7 oz per ton (88.9 million oz) silver; 0.09 oz/t (673,000 oz) gold; 7.6 percent (576,130 tons) zinc; and 2.9 percent (217,280 tons) lead. This is nearly identical to the previous yearís reserves and provides the operation 10 years of ore. The mine also hosts 19.3 million oz silver and 154,000 oz of gold in measured and indicated resource; and 40.2 million oz of silver and 285,000 oz of gold in inferred resource. Historically, roughly 80 percent of the Greens Creek resources have been converted to reserves. This year, definition drilling primarily focused on converting resources in the East Ore, 9A, West and Southwest Bench zones to reserves. Located near the mine portal, the 9A and East Ore and West zones are compelling target for mining. East Ore hosts 510,100 oz silver and 5,500 oz gold in indicated resource; and 12.6 million oz silver and 112,000 oz gold in the inferred category. Highlighted East Ore intercepts include 33.8 ounces-per-ton silver, 0.11 oz/t gold, 3.2 percent zinc and 1 percent lead over 11.9 feet; and 29.7 oz/t silver, 0.07 oz/t gold, 1.8 percent zinc, and 1 percent lead over 5.4 feet. Highlights from drilling at 9A, a narrower zone adjacent to East, include 52.1 oz/t silver, 0.03 oz/t gold, 10.5 percent zinc and 5.3 percent lead over 21.7 feet; 60.5 oz/t silver, 0.02 oz/t gold, 15.1 percent zinc and 7.3 percent lead over 14 feet; and 27.5 oz/t silver, 0.03 oz/t gold, 15.8 percent zinc, and 7.9 percent lead over 8.2 feet. Additionally, drilling indicates a high-grade expansion of the West zone, where one hole cut 643.5 oz/t silver, 1.8 oz/t gold, 14.9 percent zinc, and 7.8 percent lead over 4.8 feet. Hecla said these resources are immediately available to existing ramps. Drilling of Deep Southwest identified mineralization that extends north of previous mining in the zone and down to the upper limb of the NWW zone. One hole cut 47.2 oz/t silver, 0.22 oz/t gold, 4.3 percent zinc, and 2 percent lead over 7.9 feet. In addition to underground drilling, Hecla completed roughly 21,000 feet of surface exploration drilling at Greens Creek in 2017. This program targeted the Gallagher, East Ore and 5250 zones from surface. One of the first holes of this program cut a mineralized zone more than 1,500 feet west of the current ore zones at Greens Creek, indicating extensions of the known mineralization.
Hecla is also exploring Kinskuch, a silver project in northwestern British Columbia that it acquired in 2016. Three holes drilled at Kinskuch in 2011 cut significant widths of high-grade silver mineralization, including a 2.8-meter interval averaging 318 grams-per-metric-ton silver 0.40 g/t gold, 6.5 percent zinc and 2.2 percent lead. In April, Hecla and Dolly Varden Silver Corp. collaborated to carry out airborne geophysical surveys over Kinskuch and Dolly Vardenís neighboring Big Bulk copper-gold property.