Overview
Stage | Construction |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Sub-level caving
- Overhand Cut & Fill
- Unconsolidated rockfill
|
Production Start | ... |
Mine Life | 11 years (as of Jan 1, 2021) |
The Yauricocha shaft, currently under construction, will provide access down to 1270 level and is expected to be in production in 2025. |
Source:
p. 24
Company | Interest | Ownership |
Sierra Metals Inc.
|
81.84 %
|
Indirect
|
Sociedad Minera Corona, SA
(operator)
|
100 %
|
Direct
|
Sierra Metals Inc. owns 81.84% of Minera Corona, which in turn owns 100% of the Yauricocha Mine.
Contractors
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Deposit Type
- Hydrothermal
- Vein / narrow vein
- Manto
Summary:
The Yauricocha mine features several mineralized zones which have been emplaced along structural trends, with the mineralization itself related to replacement of limestones by hydrothermal fluids related to nearby intrusions. The mineralization varies widely in morphology from large, relatively wide, tabular manto-style deposits, to narrow, sub-vertical chimneys. The mineralization features economic grades of Ag, Cu, Pb and Zn, with local Au to a lesser degree. The majority of the mineralization is related to the regional high-angle NW-trending Yauricocha fault, or the NEtrending and less well-defined Cachi-Cachi structural trend. The mineralization generally presents as polymetallic sulfides but is locally oxidized to significant depths or related to more Cu-rich mineralization.
Goyllarisquizga Formation
The oldest rocks exposed in the area are the lower Cretaceous Goyllarisquizga arenites. This formation is approximately 300 m thick and comprises thick gray and white arenites, locally banded with carbonaceous lutites as well as small mantos of low-quality coal beds and clay. In the vicinity of Chaucha, these arenites have near their base interbedded, red lutite. The arenites crop out in the cores of the anticlines southwest of Yauricocha, as beds dispersed along the Chacras uplift, and isolated outcrops in the Éxito zone.
Jumasha Formation
The mid-Cretaceous Jumasha Formation consists of massive gray limestone, averages 700 m thick, and conco ........
Mining Methods
- Sub-level caving
- Overhand Cut & Fill
- Unconsolidated rockfill
Summary:
Mechanized sub-level caving (SLC) and overhand mechanized cut and fill (MCF) mining methods are currently used in the mine to achieve production with most of the production by SLC mining methods. The mining method used varies depending on geotechnical constraints, mineralization trends, dimensions, and mine production targets.
The analysis determined that higher production rates are achievable through expansion of the use of the SLC mining method in the new production areas. Additionally, a new configuration of the SLC mining method will allow for a greater recovery of mining resources and increased productivity.
Current mine access includes two tunnels and three used for personnel access and materials movement:
• The Klepetko tunnel (3m x 3m) and the Yauricocha tunnel (3.5m x 3.5m) located at level 720 (Main transport level). These tunnels are used to delivered mineralized material directly to the Chumpe concentrator plant and also provide mine access for personnel.
• The shafts currently in service are the Central shaft, Mascota shaft and the Cachi-Cachi shaft.
• These shafts are typically used to move personnel and materials, as well as moving mineralized material and waste up to the 720-haulage level. They can move mineralized material and waste to surface if required.
• The Yauricocha shaft is currently being sunk to the 1270 level and is expected to be commissioned in 2025.
For mining between the 1170 level to 1270 l ........
Flow Sheet:
Mine haulage trucks deliver polymetallic mineralized material and oxide mineralized material to their dedicated coarse mineralized material bins. The single crushing plant batches mineralized material that is delivered to dedicated mineralized material bins to each processing line. Each process line includes a grinding stage and a sequential differential flotation plant.
Flow Sheet:
Summary:
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Source:
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Projected Production:
Sierra has decided that the 5,500 tpd production rate option is the recommended case for a future pre-feasibility study. Increased production rates beyond 5,500 tpd may be possible once Yauricocha has resolved the mineralized material and waste haulage issues.
Commodity | Units | LOM |
Silver
|
M oz
| 11 |
Gold
|
koz
| ...... |
Copper
|
M lbs
| ...... |
Lead
|
M lbs
| ...... |
Zinc
|
M lbs
| ...... |
All production numbers are expressed as payable metal.
Operational Metrics:
Metrics | |
Daily ore mining rate
| ...... |
Daily milling capacity
| ...... |
Annual ore mining rate
| ...... |
Annual milling capacity
| ...... |
Waste tonnes, LOM
| ...... |
Ore tonnes mined, LOM
| ...... |
* According to 2021 study.
Reserves at March 31, 2021:
Category | Tonnage | Commodity | Grade | Contained Metal |
Measured & Indicated
|
14,310 kt
|
Silver
|
43.69 g/t
|
20.1 M oz
|
Measured & Indicated
|
14,310 kt
|
Gold
|
0.52 g/t
|
240.4 koz
|
Measured & Indicated
|
14,310 kt
|
Copper
|
1.14 %
|
360.7 M lbs
|
Measured & Indicated
|
14,310 kt
|
Lead
|
0.63 %
|
199.2 M lbs
|
Measured & Indicated
|
14,310 kt
|
Zinc
|
2.1 %
|
662.5 M lbs
|
Inferred
|
11,566 kt
|
Silver
|
29.04 g/t
|
10.8 M oz
|
Inferred
|
11,566 kt
|
Gold
|
0.44 g/t
|
161.8 koz
|
Inferred
|
11,566 kt
|
Copper
|
1.4 %
|
358.1 M lbs
|
Inferred
|
11,566 kt
|
Lead
|
0.32 %
|
82.7 M lbs
|
Inferred
|
11,566 kt
|
Zinc
|
1.03 %
|
261.9 M lbs
|
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