The purpose of the pilot is to show that the company will have the ability to treat both the drainage water of the now water-filled Viscaria mine as well as the water that will be discharged when the mine has returned to production. Copperstone has so far invested approximately SEK 25 million into the water treatment project. The test facility has the capacity to treat between 50–100 cubic meters of water per hour. This corresponds to up to one-sixth of the expected volume at steady-state mining and drainage.

„It is, of course, extremely gratifying that we now have proof-of-concept that we can meet our own high standards that we presented in the permit application. It also demonstrates that the technology is sufficient for the requirements that we expect to be included in the future environmental permit for the business. In fact, the treatment technology enables us to improve the water environment even before obtaining permission, both in the stream Pahtajoki and in the lake Luossajärvi“, comments Copperstone’s Head of Sustainability Anders Lundkvist.

responsible future mining

„The levelof innovation in the combined Copperstone and TeVe team has been impressive and it is with great excitement and anticipation that we will now drive the scale-up ahead of the planned restart of the Viscaria mine. This investment is one of many examples that show our commitment and dedication to responsible future mining,“ says Copperstone CEO Anna Tyni.

Copperstone intends to scale up the test facility to full capacity after a granted environmental permit and well ahead of the mine reopening. Copperstone is committed to treat water during the drainage, operation and post-treatment phases and has therefore worked hard to investigate what technologies are possible.

The tests have taken place with flows of up to 100 cubic meters per hour, which shows that it is possible to continuously treat significant water flows with ground-breaking results, while the water that now naturally drains from the mine can be treated and significantly improve downstream water environments.

The various components that make up Copperstone’s treatment plant have previously been used separately in other designs. Copperstone will now begin long-term testing of the treatment plant and will thus further improve the basis of the ongoing investigation and at the same time treat the water that is currently released from the old mine.

Background

The Viscaria mine was previously operated by LKAB and Outokumpu during the 1980s and 90s, mainly through underground mining. The tunnels in the mine were drained so that the ore could be mined. When the Viscaria mine was shut down in 1997, in accordance with environmental requirements at the time, the pumps were turned off, which meant that the mine has slowly been filled with water again. The old mine shafts and copper ores have since leached minerals and other substances that have degraded the quality of the groundwater.

Measurements show that the Viscaria mine currently discharges elevated levels of, among other things, zinc, copper and uranium. Copperstone has investigated these more closely and sought solutions to both reduce the negative impact from previous operations and prevent negative impact from its own, future mining operations.

Outokumpu Oyj and later Avalon/Sunstone (from 2018) began taking regular water samples (so-called base line studies) monthly, which Copperstone has continued to do since the acquisition of Viscaria in March 2019. Copperstone has also increased the sampling of the water flow to see how variations over time affect the mineral levels in the water.