Name of the Mine
Pyhäsalmi mine.
Location
In central Finland, on Lake Pyhäjärvi.
Mine Owner/s
First Quantum Minerals.
Brief Description
Pyhäsalmi is one of the oldest and deepest underground mines in Europe, as well as one of the most efficient, noncaving mines in the world.
The remaining life-of-mine was expected to be less than one-year from December 31, 2020. The mine’s life was later extended to June 2021.
Pyrite supply will extend until 2025, based on reclaiming pyrite from tailings.
Brief History
Pyhäsalmi was initially developed by Outokumpu Oyj in 1962 after the deposit was unexpectedly discovered by a farmer.
Outokumpu sold the mine to Inmet in 2002 and continued underground production. First Quantum acquired Pyhäsalmi in 2013 through its acquisition of Inmet.
Primary Metals/Minerals
Copper.
Secondary Metals/Minerals
Pyrite and zinc.
Geology/Mineralisation
The Pyhäsalmi deposit is a copper/zinc volcanogenic massive sulphide deposit of Proterozoic age.
Reserves
Total proven and probable reserves as at December 31, 2020, were estimated at 400 000 t grading 0.58% copper, 0.29% zinc, 0.4 g/t gold, 10 g/t silver and 43.12% sulphur.
Resources
Total measured and indicated resources as at December 31, 2020, were estimated at 4.09-million grading 0.5% copper, 0.3% zinc, 0.4 g/t gold, 10 g/t silver and 40.85% sulphur.
The remaining life-of-mine was expected to be less than one-year from December 31, 2020.
Mining Method
Underground – nonentry, bulk open stope mining methods in a primary-secondary sequence.
Major Infrastructure/Equipment
After single-stage primary crushing by an underground jaw crusher, ore is hoisted to a fines crushing plant. This is followed by conventional flotation comprising three sequential flotation circuits, one each for copper, zinc and pyrite.
Prospects
Mine closure plans, including dismantling and earthworks, are being planned in accordance with legal requirements and best practice.
Planning is in place for the mine facilities and associated infrastructure to be repurposed to take advantage of Pyhäsalmi's unique deep underground infrastructure. Proposed new activities include underground physics laboratories, a secure underground data facility, pumped hydroelectrical energy storage, laboratories for plant and fungus growing, as well as the experimental production of insects and fish.
Contact Details
First Quantum Minerals
Tel +1 416 361 6400
Email info@fqml.com
Website https://www.first-quantum.com/
Sources
First Quantum Minerals. Website https://www.first-quantum.com/ [accessed March 15, 2022]