Name of the Project
South Crofty tin project.
Location
Cornwall, UK.
Project Owner/s
Cornish Metals, formerly Strongbow Exploration.
Project Description
South Crofty has one of the highest-grade tin mineral resources in the world not currently in production and has the potential to be among the lowest-cost producers globally.
Significant mine infrastructure is still in place, most notably several mine shafts that can be used for future production and ventilation purposes. The operation is located within an industrial area, with access to the national electricity grid and existing transport infrastructure.
A preliminary economic assessment (PEA) on the South Crofty mine indicates that the project is potentially economically viable and technically feasible.
The mineralised material mined in the PEA indicates that 2.58-million tonnes at an average grade of 1.55% tin are amenable to mining.
The mine is expected to be accessed using the existing New Cook’s Kitchen shaft, which will serve as the primary access to the mine for personnel and materials, and for transporting mill feed to the plant site.
The existing Tucking mill decline will be extended in the second half of the mine life and eventually provide an alternative haulage route from the upper levels, as well as access and ventilation. The existing New Roskear shaft will provide ventilation and secondary egress during development and early mine life.
Mill feed of up to 350 000 t/y is planned, primarily using sublevel longhole mining. Delayed thickened tailings will be used as backfill to support some mining areas.
Mining blocks will be about 60 m along strike and 20 m to 30 m high.
Mineralised material will be removed from the stopes using 3.5 t load-haul-dump vehicles and transported to the existing shaft hoisting infrastructure using 20 t trucks.
All development and rehabilitation work will be conducted using single-boom hydraulic jumbo drills to widen the existing access development from 2.4 m × 2.4 m to 3.0 m × 3.5 m to allow for trackless mining.
Potential Job Creation
The project has the potential to create about 110 new jobs during the 24- to 36-month dewatering and construction period, excluding construction personnel and contractors.
The mine has the potential to directly employ about 275 people in permanent positions.
Net Present Value/Internal Rate of Return
The project has an after-tax net present value, at a 5% discount rate, of $130.5-million and an internal rate of return of 23.4%, at assumed metal prices of $10.00/lb tin, $2.65/lb copper and $0.90/lb zinc, with a payback of 3.8 years.
Capital Expenditure
The project has an estimated preproduction capital cost, including contingency, of $118.7-million.
Planned Start/End Date
The project is expected to be completed in 2026.
Latest Developments
Cornish Metals is making good progress to return the South Crofty mine to production.
The company aims to commission the mine water treatment plant in June this year, followed by full-scale dewatering operations in July.
At a design rate of 25 000 m3/d, the plant will take about 18 months to dewater the historic mine.
In addition to the mine dewatering programme, Cornish Metals is continuing with metallurgical, feasibility study and exploration work.
As part of the ongoing feasibility study, the company has retained the services of Mike Hallewell, the former mill superintendent and chief metallurgist at South Crofty and Wheal Jane, to assist with the collection of a representative metallurgical sample and advise on certain studies.
Key Contracts, Suppliers and Consultants
Siltbuster Process Solutions and Nomenca (process specification and outline design works).
Contact Details for Project Information
Cornish Metals, tel +1 604 200 6664 or email info@cornishmetals.com.