Overview
Stage | Permitting |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Sub-level stoping
- Cemented backfill
|
Mine Life | 8 years (as of Jan 1, 2017) |
The South Crofty Project is split into two areas, an Upper Mine which is polymetallic (tin-copper-zinc) and a Lower Mine which is tin only. The Upper Mine includes 9 individual polymetallic lodes whereas the Lower Mine encompasses 9 zones or clusters of lodes. |
Latest News | Cornish Metals Releases Updated Mineral Resource Estimate for South Crofty Tin Project September 14, 2023 |
Source:
p. 3
The Company’s 100% interest in the Cornwall mineral projects is held indirectly through South Crofty Limited (previously Western United Mines Limited), which is a wholly-owned subsidiary of Cornish Metals Limited (previously Strongbow Exploration (UK) Limited), itself a wholly-owned subsidiary of the Company. The Company’s mineral rights in Cornwall are held indirectly through Cornish Mineral Limited (Bermuda), which is a wholly-owned subsidiary of Cornish Metals Limited.
Contractors
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Deposit Type
- Intrusion related
- Vein / narrow vein
- Metamorphic hosted
- Epithermal
Summary:
The Devonian to Carboniferous sedimentary and volcanic package was deformed during the Variscan Orogeny. Crustal thickening of the package during the initial phase of the orogeny followed by subsequent lithospheric extension and crustal subsidence resulted in anatexis of the metasedimentary package and formation of the Cornubian batholith. The Cornubian granite is coarse-grained and enriched in a variety of elements including potassium, lithium, uranium, thorium, tin, tungsten, copper, chlorine, fluorine, and rare earth elements. The enrichment in radiogenic elements such as potassium, uranium and thorium and strong thermal activity has resulted in it being classified as a high-heat producing (HHP) granite.
Metal deposits in Cornwall are directly related to the HHP granites. Slow crystallization and possible internal reheating of the granites are considered to have resulted in fractionation of metals which were transported and concentrated by late-stage meteoric fluids.
The geology of the South Crofty Project area consists of metasedimentary and minor metavolcanic rocks of the Mylor Slate formation, locally known as “Killas” and granite of the Cornubian batholith. The Project area is located on the northwestern flank the Permian Carn Brea granite, the outcrop of which forms the hills of Carn Brea, Carn Arthen and Carn Entral. The Carn Brea granite is a satellite of the main Carnmenellis granite which is the major pluton of the district. The contact of th ........

Mining Methods
- Sub-level stoping
- Cemented backfill
Summary:
Mine development will be carried out using trackless rubber tired equipment utilizing ramps and horizontal accesses from the New Cook’s Kitchen Shaft (“NCK shaft”). Existing shafts in the South Crofty Mine will be accessed by the development and will be deepened where necessary for ventilation and manways. The NCK shaft will be the main production shaft after refurbishment once new winder (hoist) components and conveyances are installed and commissioned.
The underground mine production has been scheduled at a steady-state rate of 1,000 tpd on a 7 day work schedule but could be scheduled at 1,200 tpd on a 6 day schedule. The NCK shaft hoisting facility will have the capacity to handle either level of production.
NCK shaft is the main access point for the underground workings, with the vertical shaft extending to a final depth of 769 m below shaft collar. Further sub-declines extend from the lower depths of NCK shaft and reach an eventual maximum depth of 885 m below surface.
Where applicable, stopes will be mined out entirely without any backfill, especially stopes at the top of the mine panel and remnant or isolated stopes. Since the underground ground conditions are expected to be good, and the mine has been operated in the past with minimal backfill, it is expected that stope backfill can either be delayed after a stope is mined or many stopes will not require backfill for ground support.
Within the current estimates to refurbish ........

Source:

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Flow Sheet:
Summary:

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Projected Production:
Commodity | Product | Units | Avg. Annual | LOM |
Tin
|
Concentrate
|
kt
| | 60 |
Tin Equivalent
|
Metal in concentrate
|
M lbs
| | ......  |
Tin
|
Metal in concentrate
|
kt
| 4.4 | |
Operational Metrics:
Metrics | |
Daily ore mining rate
| 1,000 t * |
Daily processing rate
| 1,000 t * |
Annual ore mining rate
| 350,000 t * |
Annual processing rate
| 350,000 t * |
Tonnes processed
| 2.58 Mt * |
Total tonnes mined, LOM
| 2,574,700 t * |
* According to 2017 study.
Reserves at June 7, 2021:
Mineral Resources are reported at a cut-off grade of 0.6% SnEq and a minimum mining width (MMW) of 1.2 m.
Category | Tonnage | Commodity | Grade | Contained Metal |
Indicated
|
2,084 kt
|
Tin
|
1.59 %
|
33 kt
|
Indicated
|
277 kt
|
Tin Equivalent
|
1.01 %
|
3 kt
|
Inferred
|
1,937 kt
|
Tin
|
1.67 %
|
32 kt
|
Inferred
|
493 kt
|
Tin Equivalent
|
0.93 %
|
5 kt
|
Type | Material | Diameter | Length | Description |
Corporate Filings & Presentations:
Document | Year |
Fact Sheet
|
2022
|
...................................
|
2021
|
...................................
|
2021
|
...................................
|
2021
|
...................................
|
2020
|
...................................
|
2020
|
Preliminary Economic Assessment
|
2017
|
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