Drilling to enhance exceptional Greens Creek
Last updated 5/18/2018 at 4:21am
Hecla Mining Company May 8 said first quarter exploration drilling continues to expand high-grade silver resources along the East Ore, Upper Plate, Deep 200 South and Deep Southwest mineralized trends at its Greens Creek Mine in Southeast Alaska.
"(D)rilling at Greens Creek continues to discover high-grade mineralization that could enhance the already exceptional mine economics and mine life," said Hecla President and CEO Phillips Baker, Jr.
Hecla said the high-grade intersections encountered during definition drilling East Ore Zone – including one hole that averaged 47.2 ounces of silver per ton, 0.76 oz/ton gold, 23.1 percent zinc and 12.6 percent lead over 12.9 feet; and another averaging 10.2 oz/ton silver, 0.09 oz/ton gold, 8.1 percent zinc and 4.3 percent lead over 31.5 feet – compare favorably to previously modeled resource estimates, particularly at higher elevations.
The company said step-out drilling at East Ore Zone – including an intersection of 23.2 oz/ton silver, 0.02 oz/ton gold, 3.97 percent zinc and 1.68 percent lead over 10.4 feet – suggest strong mineralization continues beyond the resource to the south and at depth.
Aggressive drilling of the East Ore Zone will continue throughout 2018 and into 2019 targeting the northern extent of the East Ore Zone.
Definition drilling of the southern portion of the Deep 200 South Zone – including 28.9 oz/ton silver, 0.05 oz/ton gold, 2.1 percent zinc and 1.2 percent lead over 16.4 feet – confirmed the high grades found there and upgraded this portion of the zone to the indicated resource category.
Exploration drilling south of the current 200 South Bench resource has extended mineralization another 400 feet. One hole drilled in this expansion area cut 31.9 feet averaging 24 oz/ton silver, 0.02 oz/ton gold, 0.9 percent zinc and 0.5 percent lead.
Hecla said recent exploration drilling further south suggests 200 South Bench mineralization remains robust.
Drilling of the Upper Plate Zone suggests the two, flat-lying ore zones found there, which are near the mine portal elevation, could be thicker than modeled and higher in elevation toward the west.
Definition drilling at Upper Plate Zone 32.1 oz/ton silver, 0.18 oz/ton gold, 4.8 percent zinc and 2.5 percent lead over 13.8 feet. Step-out drilling at the upper reaches of the underground workings at Greens Creek cut 4.1 feet of 15.9 oz/ton silver, 1.7 percent zinc and 0.9 percent lead more than 100 feet south of the current resource.
Hecla said underground and surface drilling during the second quarter will target further expansion of the Upper Plate Zone resource.
In the deepest reaches of the underground mine drilling targeting the Deep Southwest Zone, an extension of the Southwest Zone and 200 South Zone. Drilling here intersected 22.04 oz/ton silver, 10.18 percent zinc, and 5.14 percent lead over 2.49 feet.
The Idaho-based miner said drilling of the Gallagher Zone, also located at the lower elevations at Greens Creek, confirmed modeled thicknesses and may have increased the resource by defining mineralization further to the west beyond the current resource. Intersections from this program include 7.2 oz/ton silver, 0.12 oz/ton gold, 10.5 percent zinc and 5.6 percent lead over 4.6 feet.
Exploration drilling also intersected rock units with the same characteristics as Gallagher ore more than 750 feet west but on trend. Future drilling is planned to further evaluate this area to see if the current precious metal-rich mineralization transitions into broader and higher-grade precious and base metal-rich mineralization.
Hecla said underground drilling at Greens Creek will continue to focus on the East Ore, Upper Plate, Deep 200 South zones throughout 2018 with additional drilling targeting the Lower Southwest, Northwest West and Southwest Bench zones.
Surface drilling is slated to start in June and will evaluate expansions to the Upper Plate, North Gallagher, Southwest Bench and 5250 zones.
Hecla also plans to resume exploration drilling at Kinskuch, a silver project in northwestern British Columbia that it acquired in 2016.
"In the second quarter, we plan to initiate drilling programs at Kinskuch in northern British Columbia, Little Baldy in Idaho and on surface at Greens Creek," said Baker, Jr.