Information with respect to probable ore reserves, mineralized material, and other resources is set forth below, and represents our 100% ownership of Greens Creek after April 16, 2008.
(as of December 31, 2011)
Tons |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
Silver (oz) |
Gold (oz) |
Zinc (tons) |
Lead (tons) |
|||
| Probable Reserves Mineralized Material (1) Other Resources (2) |
7,991,000 445,900 4,416,700 |
12.3 5.81 11.9 |
0.093 0.109 0.093 |
9.2 |
3.5 |
98,383,300 |
742,400 |
733,140 |
281,620 |
(1) Indicated resources, Gallagher orebody, factored for dilution and mining recovery.
(2) Inferred resources, East, West, SW, Gallagher, NWW, '9A', and 2005 orebodies, factored for dilution and mining recovery.
The United States Securities and Exchange Commission permits mining companies, in their filings with the SEC, to disclose only those mineral deposits that a company can economically and legally extract or produce. We use certain terms on this website, such as "resource," "other resources," and "mineralized materials" that the SEC guidelines strictly prohibit us from including in our filing with the SEC. U.S. investors are urged to consider closely the disclosure in our Form 10-K, included on this website.
geology
The Greens Creek deposit is a polymetallic, stratiform, massive sulfide deposit. The host rock consists of predominantly marine sedimentary, and mafic to ultramafic volcanic and plutonic rocks, which have been subjected to multiple periods of deformation. These deformational episodes have imposed multiple folding of the orebodies to create a complex geometry. Mineralization occurs discontinuously along the contact between a structural hanging wall of quartz mica carbonate phyllites, and a structural footwall of graphitic and calcareous argillite.
Ore lithologies fall into two broad groups: massive ores with over 50% sulfides and white ores with less than 50% sulfides. The massive ores are further subdivided as either being base-metal or pyrite dominant. Massive ores vary greatly in precious metal grade from uneconomic to bonanza Au (>.5 opt) and Ag (>100 opt). White ores are subdivided into three groups by the dominant gangue mineralogy; white carbonate, white siliceous, and white baritic ore. These ores tend to be base-metal poor and precious-metal rich. Major sulfide minerals are pyrite, sphalerite, galena, and tetrahedrite/tennanite.
exploration
At the Greens Creek mine in Alaska, approximately 94,559 feet of underground in-fill (definition) and exploration drilling and 27,398 feet on surface was completed through 2011. The drilling tested the trends of known zones including the Gallagher, 5250 South, 200 South and the NWW resulting in a replacement of tons mined during 2011. In 2011, underground drilling in the Gallagher zone delineated several higher-grade resources within a thicker mineralized body. In the 200 South zone, drilling continues to outline a precious metal-enriched body that added 35,000 tons of new reserves and in the NWW zone, in-fill drilling converted 100,000 tons of resources to reserves. Definition of new reserves and resources in the last ten years has been able to replace mineral during that period.
The Greens Creek exploration program should exceed $7 million in 2012 with drilling planned at the Gallagher, 200 South, West Wall, NWW and 5250 zones. Two drills are expected to work underground all year, and the surface exploration program has three drills and a number of surface mapping and sampling crews in the spring and summer. Exploration along the NE contact will use underground and surface drills.
The drilling designed to test the down plunge extent of the main Gallagher mineralization to the west and south has defined a broad zone of mineralization over approximately 200 feet of strike and 400 feet down dip containing narrower 2.3 to 7.4 feet high-grade precious and base metal intervals. Drilling in the 200 South has defined two separate mineralized limbs that are typically barite-rich and contain higher values of precious metals relative to other zones in the mine. Definition drilling covered a strike length of 250 feet and added 35,000 tons of new reserve at 0.55 ounces per ton gold, 59.5 ounces per ton silver, 12.4% lead and 26.73% zinc. Exploration drilling outlined the mineralized fold another 450 feet to the south of the resource but drilling is too wide-spaced to define a resource.
Hecla continues to be encouraged with the North East (“NE”) contact, a relatively new target area that is located below the mine infrastructure. Surface and underground drilling continue to define the NE contact which represents a continuation of the Greens Creek mine contact. The contact has been folded underneath the current mine workings; it extends near surface at Cub Creek, north of the current mine infrastructure, and dips below and sub-parallel to the current mine infrastructure.
On surface at Greens Creek, two holes at West Bruin, two miles NNW of the mine infrastructure, intersected 5 to 14 foot-wide zones that encompass chalcopyrite and sphalerite-bearing vein mineralization. Final results from West Bruin showed nearby mine contacts with anomalous silver and zinc and elevated gold values. Similar chalcopyrite-bearing mineralization was intersected at Cub #4, just over one mile north of the mine. Assay results from the Cub #5 show up to 2% copper and1.5 ounces per ton silver with highly anomalous lead and zinc in pyritic muds at the mine contact. Drill holes targeting the south end of the East Ore trend intersected weakly mineralized argillite near the mine contact in for over 300 feet along strike. All three targets are likely to continue to be drilled in the summer of 2012.
Some of the high priority underground and surface targets where upside potential exists include:
- Further extension of the high-grade, precious metal-rich 200 South and 5250 zones, and further definition of two new and distinct limbs below the current workings on the NWW zones which will be added to the reserves and resources;
- Gallagher zone to the southwest is open in three directions and will be one of the primary underground exploration areas in 2012;
- Surface and underground drilling continues to define the NE contact which represents a continuation of the Greens Creek mine contact. The contact has been folded underneath the existing mine workings, extends near surface at Cub Creek less than a mile northeast of the mine infrastructure, and dips below and is sub-parallel to the mine infrastructure. Recent wide-spaced drilling has defined discontinuous mineralized intervals along the contact which has a folded strike length of over 5,000 feet and down dip extension of 3,000 feet. The NE contact’s dimension compares to the current Greens Creek deposit; and
- To the north of the mine area, surface exposures of mineralized mine contact at Cub, West Bruin Killer Creek and West Gallagher will be evaluated by surface drilling over the next year.
(Q2 2011)
| Area |
Width (Feet) |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
||
| Lower SW Lower SW |
5.00 1.00 |
38.50 24.35 |
0.095 0.710 |
4.66 17.56 |
2.65 8.26 |
latest assay table results – Gallagher
(Q4 2011)
| Area |
Width (Feet) |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
||
Gallagher Gallagher Gallagher |
3.6 3.1 5.0 2.2 9.5 4.5 5.2 4.4 9.5 2.3 3.3 6.4 |
29.1 15.1 18.1 10.5 9.2 9.8 18.3 13.8 9.2 13.2 10.2 18.5 |
0.22 0.26 0.21 0.19 0.23 0.31 0.26 0.21 0.23 0.25 0.24 0.21 |
10.9 5.2 17.8 8.1 5.8 11.2 12.4 17.8 5.8 2.8 6.8 4.1 |
4.9 4.3 6.9 3.7 2.8 3.2 5.1 6.9 2.8 2.8 5.2 1.7 |
(Q3 2011)
| Area |
Width (Feet) |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
||
| Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher |
6.60 2.60 6.40 26.30 2.70 6.60 2.70 2.30 5.30 7.40 |
13.42 3.36 5.76 5.59 6.54 14.26 8.53 6.55 8.28 8.86 |
0.230 0.300 0.160 0.100 0.041 0.302 0.080 0.120 0.080 0.285 |
15.83 16.78 8.90 6.38 17.62 6.85 12.22 5.31 2.95 8.83 |
4.12 8.22 3.71 2.97 3.70 2.96 5.96 2.23 1.38 4.47 |
(Q2 2011)
| Area |
Width (Feet) |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
||
| Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher Gallagher |
23.80 8.90 3.00 12.00 3.70 3.40 23.90 7.80 19.10 37.40 15.00 6.40 5.50 0.90 24.00 5.00 8.00 15.30 1.60 6.50 5.20 |
4.10 5.39 10.15 5.48 6.81 1.79 5.07 2.84 3.33 4.86 2.27 4.40 3.45 33.35 2.77 13.95 4.36 16.56 2.59 23.15 5.96 |
0.077 0.055 0.049 0.041 0.060 0.027 0.066 0.033 0.055 0.067 0.037 0.071 0.034 0.120 0.043 0.190 0.212 0.291 0.017 0.065 0.045 |
8.02 0.82 3.16 8.81 9.87 0.23 6.20 1.11 3.96 4.83 1.28 1.69 8.46 5.19 1.53 6.67 1.09 7.75 9.48 6.58 1.99 |
3.80 0.53 2.00 3.70 4.93 0.34 3.08 0.74 2.06 2.47 0.54 0.86 3.88 2.28 0.71 3.33 0.66 3.45 3.88 2.71 0.86 |
latest assay table results – NWW zone
(Q1 2011)
| Area |
Width (Feet) |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
||
| West Limb West Limb West Limb West Limb East Limb East Limb East Limb |
8.7 6.6 3.3 5.0 5.0 5.1 7.1 |
32.0 149.4 25.5 12.4 9.5 6.1 10.2 |
0.12 0.87 0.57 0.11 0.20 0.10 0.21 |
15.4 4.8 21.2 15.6 22.3 20.8 18.1 |
8.9 1.1 13.0 11.5 6.4 11.8 6.7 |
latest assay table results – 200 South zone
(Q1 2012)
| Area |
Width (Feet) |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
||
| 16.8 9.9 |
32.0 17.9 |
0.02 0.05 |
8.1 7.6 |
4.0 3.7 |
(Q4 2011)
| Area |
Width (Feet) |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
||
| Upper Limb Upper Limb Lower Limb Lower Limb |
12.0 9.4 25.6 14.8 |
10.2 18.5 16.0 16.3 |
0.14 0.21 0.05 0.24 |
3.8 4.1 8.9 4.8 |
2.2 1.7 4.6 1.8 |
(Q1 2011)
| Area |
Width (Feet) |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
||
| Upper Limb Upper Limb Upper Limb Lower Limb Lower Limb Lower Limb Lower Limb |
12.5 9.2 3.1 9.9 3.9 3.5 8.5 |
24.7 23.4 26.2 30.1 23.0 172.7 21.3 |
0.48 0.17 0.06 0.18 0.06 0.07 0.17 |
4.3 3.6 3.8 2.0 5.2 7.1 5.2 |
8.4 10.6 10.1 4.4 9.5 16.3 7.1 |
latest assay table results – 9a zone
(Q1 2012)
| Area |
Width (Feet) |
Silver (oz/ton) |
Gold (oz/ton) |
Zinc (%) |
Lead (%) |
||
16.8 10.0 8.7 19.8 21.2 8.9 22.9 6.0 3.2
|
32.0 15.3 20.7 26.1 9.7 18.0 11.6 16.5 46.6 |
0.02 0.02 0.02 0.02 0.04 0.02 0.07 0.04 0.52 |
8.1 1.3 18.2 11.5 33.4 8.2 5.9 12.9 9.3 |
4.0 0.4 8.7 6.6 10.9 4.8 3.5 2.8 2.4 |