Overview
Stage | Restarting |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Room-and-pillar
- Bench stoping
|
Production Start | ... |
Mine Life | 3.7 years (as of Jan 1, 2018) |
The Shafter silver mine has all material permits in place with extensive surface infrastructure and underground workings including portal/decline and shaft access and a processing facility rated at approximately 1,500 tons per day. Mining was discontinued after the plant commissioning and testing phase were complete, due mostly in part to lower silver prices and rushed production start-up issues. The mine was put on care and maintenance in December 2013.
Silver Hammer Mining Corp. has entered into a definitive share purchase agreement dated September 27, 2023 to acquire a 100% interest in the previously producing high-grade Shafter silver mine, from Aurcana Silver Corp. Silver Hammer has recently assembled a highly experience technical team to complete due diligence to fully evaluate and to assist in advancing the Shafter Project through an accelerated strategy to complete a mineral resource expansion, initiate mine development towards future production by 2027. |
Source:
p. 1,5,7
Aurcana owns 100% of the Shafter project through its wholly owned subsidiary, Rio Grande Mining Company (“RGMC”).
Silver Hammer Mining Corp. has entered into a definitive share purchase agreement dated September 27, 2023, to acquire a 100% interest in the Shafter silver deposit, a previously producing high-grade silver mine, from Aurcana Silver Corporation.
Completion of the Shafter Acquisition is subject to customary conditions such as shareholder approval, regulatory approvals, completion of the equity financing, the reorganization, the debt settlement, and approval of the CSE.
Contractors
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Deposit Type
- Manto
- Vein / narrow vein
- Carbonate hosted
Summary:
The Shafter silver deposit is considered an example of a polymetallic replacement deposit. Because of their irregular, but sharp contact with the enclosing carbonate host rocks, deposits of this type have been categorized as high-temperature, carbonate-hosted deposits.
Polymetallic deposits consist of massive lenses and (or) pipes, known as mantos or replacement orebodies, and veins of iron, lead, zinc, and copper sulfide minerals that are hosted by and replace limestone, dolomite, or other sedimentary rocks; most massive deposits contains more than 50 percent sulfide minerals. Sediment-hosted deposits commonly are intimately associated with igneous intrusions in the sedimentary rocks. Emplacement of these intrusions triggered mineral formation and they host polymetallic veins and disseminations that contain iron, lead, zinc, and copper sulfide minerals. Some polymetallic replacement deposits are associated with skarn deposits in which host carbonate rocks are replaced by calc-silicate±iron oxide mineral assemblages. Most polymetallic vein and replacement deposits are zoned such that copper-gold mineralization is proximal to intrusions, whereas lead-zinc-silver mineralization is laterally and vertically distal to intrusions.
There is little evidence in the Shafter district to indicate the source of the mineralizing solutions. No evidence of contact metamorphism has been noted, and this may indicate that the mineralizing solutions had traveled some dista ........
Mining Methods
- Room-and-pillar
- Bench stoping
Summary:
The relatively sub-horizontal geometry and the thickness of the mineralization suggested the use of room and pillar as the primary mining method. Longhole slashing, benching and partial pillar recovery would be employed as needed during the secondary extraction phase. A minimum mining height of 8 ft was included in the resource modeling to allow sufficient height for personnel and mechanized equipment. Areas with thickness over 15 or 20 ft can be mined using the secondary extraction methods listed above, or another variation of conventional room-and-pillar mining.
Mine design for primary extraction is based on 6.8 oz Ag/ton cutoff grade. Block grades for the stopes is the block diluted grade of the 10 ft x 10 ft x 8 ft block with a cutoff of 6.8 oz Ag/ton. The minimum mining height is 8 feet with basic heading size of 28 ft wide. Average height for the above cutoff resource base is 12 ft. Stopes were formed by successive re-blocking of the block model at higher cutoffs. The average stope width is estimated to be 140 ft from the selected resource blocks. Pillars are planned to be 24 ft by 24 ft. These stope dimensions yield a primary extraction ratio of 78%. Secondary extraction involve mining half of the pillars. Overall extraction increases to 89%, assuming half the pillar marterial is recoverable.
Once the primary extraction sequence in each work area is complete, secondary extraction would include combinations of: slashing pockets of back material ........
Source:
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Flow Sheet:
Summary:
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Source:
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Projected Production:
Commodity | Units | Daily | Avg. Annual | LOM |
Silver
|
koz
| 5.3 | 1,837 | 6,559 |
All production numbers are expressed as metal in doré.
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Operational Metrics:
Metrics | |
Daily ore mining rate
| 600 tons * |
Hourly processing rate
| 25 tons * |
Daily processing rate
| 600 tons * |
Annual ore mining rate
| 210,000 tons * |
Annual processing rate
| 210,000 tons * |
Waste tonnes, LOM
| 228.7 k tons * |
Ore tonnes mined, LOM
| 748.7 k tons * |
Total tonnes mined, LOM
| 977.3 k tons * |
Tonnes processed, LOM
| 749,000 tons * |
* According to 2018 study.
Reserves at September 15, 2023:
Mineral Resources are comprised of model blocks greater than or equal to the 4.2 oz Ag/ton cutoff.
Category | Tonnage | Commodity | Grade | Contained Metal |
Measured
|
97,000 tons
|
Silver
|
8.95 oz/ton
|
868,000 oz
|
Indicated
|
1,055,000 tons
|
Silver
|
9.42 oz/ton
|
9,935,000 oz
|
Measured & Indicated
|
1,152,000 tons
|
Silver
|
9.38 oz/ton
|
10,803,000 oz
|
Inferred
|
823,000 tons
|
Silver
|
7.67 oz/ton
|
6,315,000 oz
|
Corporate Filings & Presentations:
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