Hecla Mining Company today provided an update on its exploration programs during the fourth quarter.
- San Sebastian continues to expand high-grade, polymetallic zones similar to the Hugh Zone on the Middle and Francine veins.
- Casa Berardi has expanded and refined resources that could increase the size of the proposed Principal and current East Mine Crown Pillar (EMCP) open pits and discovered mineralization that could lead to new pits in the west part of the mine at the West Mine Pillar and NW-SW zones.
- Drilling of the 118 and 123 zones at Casa Berardi has discovered high-grade mineralization at depth and to the west.
- Greens Creek exploration continues to expand the resource by drilling on known mineralized trends.
"Our strategy of investing in exploration continues to add value, with considerable exploration success this year, including the record silver, gold and lead reserves announced last week," said Phillips S. Baker, Jr., President and CEO. "This past quarter was no different than the full year. We continue to expand the polymetallic mineralization at San Sebastian, so much so that we expect to take a bulk sample this year. At Casa Berardi, our exploration continues to confirm the high expectations we had when we acquired it, with expansions of planned pits and discovery of new open pitable material as well as new high-grade lenses underground. Finally, drilling at Greens Creek discovered high-grade mineralization in the central part of the mine that could enhance Greens Creek's already exceptional mine economics and mine life."
San Sebastian - Mexico
During the quarter, exploration with three core drills that were directed towards polymetallic mineralization successfully discovered new high-grade zones along the Middle and Francine veins.
Drilling of the 97 Zone along the West Middle Vein was directed toward a new zone of high-grade, polymetallic mineralization with similar mineral characteristics as the previously discovered Hugh Zone on the Francine Vein. The 97 Zone extends 1,000 feet along strike and 750 feet down-dip and is open to the east and at depth. This mineralization is located about 100 to 300 feet below the new Middle Vein underground mine ramp and a development drift has begun that will facilitate the collection of a bulk sample of the polymetallic mineralization this year. Recent assay results from step-out drilling include 10.2 oz/ton silver, 3% copper, 10% lead, and 18% zinc over 4.4 feet and 12.0 oz/ton silver, 4% copper, 6% lead, and 9% zinc over 5.4 feet. Drilling is planned to the east and at 1,000 feet of depth to evaluate the potential of polymetallic mineralization to extend below the 3,000 feet of strike length of the oxide reserves.
On the Francine Vein, drilling continues to intersect high-grade, polymetallic mineralization extending 600 feet to the west and 800 feet east of the current Hugh Zone resource for a total of over 5,000 feet of strike length. Recent vein intercepts suggest this polymetallic mineralization is closer to surface to the west. Recent assay results from drilling on the Francine Vein include 9.2 oz/ton silver, 2% copper, 5% lead, and 5% zinc over 6.3 feet to the east and 12.8 oz/ton silver, 2% copper, 4% lead and 6% zinc over 3.6 feet to the west.
As noted in the last quarter, a drill hole located 2,500 feet to the west of the Hugh Zone resource intersected a polymetallic vein with over six feet of true thickness. Results of step-out drilling in this area include 9.1 oz/ton silver, 3% copper, 3% lead, and 4% zinc over 2.6 feet. The vein is one of the most western intersections along the Francine Vein and is largely open between the most recent drilling west of the Hugh Zone.
Drilling continues to expand resources and evaluate polymetallic targets along the Middle and Francine veins and the plan is to also evaluate near-surface, oxide mineralization at the Provessor, North and Esperanza veins.
More complete drill assay highlights from San Sebastian can be found in Table A at the end of this release and a presentation showing drill intersection locations is available at the following: https://www.hecla.com/
Casa Berardi - Quebec
During the fourth quarter, six underground drills were used to refine stope designs, expand reserves and resources in the 118, 123, and 124 zones and confirm further potential at depth, to the west and in some cases to the east. Up to four drills on surface completed in-fill and exploration drilling that could expand the proposed Principal Pit and the current EMCP pit and discover new mineralization that could lead to pits in the west part of the mine.
At the Lower 118 Zone, drilling has confirmed the continuity of multiple mineralized lenses that extend over 1,600 feet down-plunge and remain open to depth and to the east and west of the current resources. Drilling near the bottom of the mine returned 0.90 oz/ton gold over 21.9 feet and 0.38 oz/ton gold over 37.8 feet and suggests there is good potential to extent high-grade resources to the west and to depth near the Casa Berardi Fault and below the current mine infrastructure.
Drilling of stacked, high-grade lenses of the 123 Zone is defining the connection of multiple mineralized lenses for over 1,600 feet of strike length and over 3,000 feet down-dip below the 1010 level. Drilling on the western extreme of the lower 123 Zone intersected 0.32 oz/ton gold over 37.1 feet, confirming the continuation of multiple lenses. Also, to the east there was an intersection grading 0.22 oz/ton gold over 24.0 feet. Drilling below the mine infrastructure intersected 0.41 oz/ton gold over 10.7 feet and 0.35 oz/ton gold over 11.5 feet. Drilling of the lower 123 Zone at the bottom of the mine confirmed vein continuity and shows that it is open at depth and to the east and west of the current resources.
Intersections from drilling on the upper part of the 124 Zone include 0.91 oz/ton gold over 4.6 feet and 0.42 oz/ton gold over 17.7 feet, suggesting mineralization continues down from surface and is open at depth and to the west. Drilling in this area has also confirmed the high-grade nature of the crown pillar below the proposed Principal Pit.
Surface and shallow underground drilling have identified extensions of potential pits that are being evaluated for production. Drilling along the northeast extension of the proposed Principal Pit area confirmed 1,200 feet of continuity to the northeast and includes an intersection of 0.11 oz/ton gold over 7.2 feet. Drilling targeting the shallow eastern extension of the 124 Zone intersected strong mineralization including 0.14 oz/ton gold over 9.7 feet. Underground drilling of this target is planned to evaluate deeper extensions of the high-grade shoots. Drilling on the west extension of the current EMCP pit has returned 0.09 oz/ton gold over 27.8 feet and 0.07 oz/ton gold over 50.7 feet to define an extension over 700 feet to the west of the current pit outline.
Drilling of the West Mine Surface Pillar within 800 feet of surface to the west of the west shaft intersected a broad mineralized zone of 0.04 oz/ton gold over 78.7 feet that contains an interval of 0.12 oz/ton gold over 13.8 feet. In-fill drilling in 2018 may convert a large portion of those resources to indicated category with the eventual incorporation into the life of mine plan.
Aggressive surface drilling programs are planned through 2018 at the 124 Zone (Principal area), 146/EMCP, West Mine Surface Pillar and South West zones to define a possible series of open pits along the Casa Berardi Fault. Underground drilling is expected to continue to expand and refine the lower 118, 121 and 123 zones lower in the mine.
More complete drill assay highlights from Casa Berardi can be found in Table A at the end of the release and a presentation showing drill intersection locations is available at the following: http://ir.hecla-mining.com/interactive/newlookandfeel/4130678/Hecla-Q4-2017ExplorationUpdate.pdf
Greens Creek - Alaska
At Greens Creek, drilling in the fourth quarter, targeting the East Ore, Deep 200 South, Gallagher, Deep Southwest and West zones, upgraded and expanded the known resources. Strong assay results were also received from previous drilling on the East Ore, Gallagher and Deep 200 South zones.
In the East Ore Zone intersections from definition drilling, including 32.3 oz/ton silver, 0.18 oz/ton gold, 9.0% zinc and 4.8% lead over 19.8 feet, compare favorably to previously modeled resource estimates, particularly at higher elevations. Step-out drilling, including an intersection of 54.2 oz/ton silver, 0.43 oz/ton gold, 4.25% zinc and 1.34% lead over 19.0 feet, suggest strong mineralization continues beyond the resource to the south and at depth. Aggressive drilling of the East Ore Zone is planned to continue well into 2018 with the goal of confirming reserves and expanding the known resource.
Definition drilling of the southern portion of the Deep 200 South Zone, including 40.1 oz/ton silver, 0.03 oz/ton gold, 6.0% zinc and 4.2% lead over 18.9 feet, improved the high-grades and upgraded it to indicated resource. Exploration drilling south of the current resource has extended 200 South Bench mineralization another 300 feet with an intersection of 23.6 oz/ton silver, 0.06 oz/ton gold, 2.5% zinc and 1.3% lead over 19.5 feet. Recent exploration drilling further south suggests the bench mineralization remains robust.
Drilling of the Gallagher Zone confirmed modeled thicknesses and may have increased the resource by defining mineralization further to the west and east beyond the current resource. Intersections from this program include 25.3 oz/ton silver, 0.01 oz/ton gold, 0.7% zinc and 0.3% lead over 9.4 feet and 8.4 oz/ton silver, 0.03 oz/ton gold, 11.8% zinc and 6.4% lead over 11.2 feet.
Underground drilling for the remainder of the year is planned to focus on the East Ore, Upper Plate, Deep 200 South, and Gallagher zones.