Overview
Stage | Production |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Cut & Fill
- Drift & Fill
- Longhole stoping
- Paste backfill
|
Production Start | ...  |
Mine Life | 2034 |
Hecla’s Greens Creek Mine in southeast Alaska is one of the largest and lowest-cost primary silver mines in the world. |
Source:
p. 47
The Project core claims at Big Sore are held in the name of Hecla Greens Creek Mining Company, a wholly-owned Hecla subsidiary.
Contractors
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Summary:
Work by Taylor and Johnson (2010) in the USGS Professional Paper 1763 indicated that the Greens Creek deposit displays a range of syngenetic, diagenetic, and epigenetic features that are typical of volcanic massive sulfide deposits (VMS), sedimentary exhalative (SEDEX), and Mississippi Valley-type (MVT) genetic models. Based on those observations the investigators indicated that the Greens Creek mineral deposit was a ‘hybrid’ type with elements of several deposit models.
Due to variations in mineralization, structural complexity, and spatial location, the Greens Creek mineralization is segregated into nine separate mineralized zones. In order from easternmost and highest elevations to westernmost, the zones are:
• East;
• West;
• 9A;
• Northwest West;
• Upper Plate;
• 5250;
• Southwest;
• 200 South;
• Gallagher.
The mineralization is stratigraphically controlled and typically found at the contact between the phyllites (stratigraphic footwall) and the argillites (stratigraphic hanging wall). Due to the intense structural deformation, mineralization may be tightly folded into the phyllite or argillite packages such that the original stratigraphic relationships are unclear. In rare cases there may be areas where the mineralized materials are stratigraphically above the phyllite/argillite contact but still proximal to it.
On a gross deposit scale the mineralization trends N 30° W and plunges to the so ........

Mining Methods
- Cut & Fill
- Drift & Fill
- Longhole stoping
- Paste backfill
Summary:
Greens Creek is a portal accessed mine that utilizes conventional rubber-tired mining equipment, and drill and blast techniques. Production mining is primarily executed using cut and fill and drift and fill methods, supplemented by longhole stoping where orebody geometry permits.
The orebody is complex which has resulted in each of the nine mining zones being unique in size and shape. Each requires differing levels of mine development infrastructure which is included in the mine plan. Ore handling is performed with a fleet of underground haulage trucks and scoop trams or load-haul-dump units (LHDs). Waste is either trucked out of the mine to the waste disposal area or is placed in previously mined-out stopes when available. All LHDs are equipped with remote operating capability and can be operated from an operations room on surface. Production areas are backfilled with either paste fill, created from concentrator tailings, or cemented or uncemented rock depending on future strength requirements.
Fresh air is fed into the mine via the 920 level access portal and distributed through a series of internal ramps and raises, and exhausts through the 1350 level portal and the 2853 surface raise. A ventilation on demand (VOD) system is currently in place in a limited number of headings and is planned to be extended to the remainder of the mine.
The LOM plan is based on a 2,300 stpd production rate continuing through to the end of mine life in 2035. Or ........

Source:

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Flow Sheet:
Summary:

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Reserves at December 31, 2022:
The reserve and resource NSR cut-off values for Greens Creek are $210/ton for all zones except the Gallagher Zone at $215/ton; metallurgical recoveries (actual 2022): 81% for silver, 72% for gold, 82% for lead, and 89% for zinc.
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
7 k tons
|
Silver
|
16.1 oz/ton
|
108 koz
|
Proven
|
7 k tons
|
Gold
|
0.07 oz/ton
|
0.4 koz
|
Proven
|
7 k tons
|
Lead
|
2.3 %
|
150 tons
|
Proven
|
7 k tons
|
Zinc
|
5.4 %
|
360 tons
|
Probable
|
10,668 k tons
|
Silver
|
10.9 oz/ton
|
116,748 koz
|
Probable
|
10,668 k tons
|
Gold
|
0.09 oz/ton
|
935 koz
|
Probable
|
10,668 k tons
|
Lead
|
2.5 %
|
264,600 tons
|
Probable
|
10,668 k tons
|
Zinc
|
6.5 %
|
694,800 tons
|
Proven & Probable
|
10,675 k tons
|
Silver
|
10.9 oz/ton
|
116,856 koz
|
Proven & Probable
|
10,675 k tons
|
Gold
|
0.09 oz/ton
|
935 koz
|
Proven & Probable
|
10,675 k tons
|
Lead
|
2.5 %
|
264,750 tons
|
Proven & Probable
|
10,675 k tons
|
Zinc
|
6.5 %
|
695,160 tons
|
Indicated
|
8,421 k tons
|
Silver
|
12.9 oz/ton
|
108,717 koz
|
Indicated
|
8,421 k tons
|
Gold
|
0.1 oz/ton
|
810 koz
|
Indicated
|
8,421 k tons
|
Lead
|
2.9 %
|
245,990 tons
|
Indicated
|
8,421 k tons
|
Zinc
|
8 %
|
675,740 tons
|
Inferred
|
2,383 k tons
|
Silver
|
12.1 oz/ton
|
28,949 koz
|
Inferred
|
2,383 k tons
|
Gold
|
0.07 oz/ton
|
178 koz
|
Inferred
|
2,383 k tons
|
Lead
|
2.8 %
|
67,400 tons
|
Inferred
|
2,383 k tons
|
Zinc
|
6.9 %
|
164,080 tons
|
Source:

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