OKD starts backfilling ventilation shaft at ČSM-South mine

OKD today began backfilling the ventilation shaft at the southern section of the ČSM Mine in Stonava, in the Karviná region. This followed the completion of 87 explosion-proof seals used to close off mine workings. David Hájek, the mine’s closure director and mine manager, told reporters that backfilling the shaft will take around 11 days.

"We will decommission the shaft, which is approximately 900 metres deep, by backfilling it with material we produced while we were still mining coal, as a by-product of the processing plant. It is certified stone and has the right parameters," Hájek said.

The material passes through a screen, with the maximum specified particle size being 100 millimetres. "It must be placed gradually so that no arches form beneath which voids could remain, potentially causing unplanned settlement of the backfill," the mine manager explained. OKD workers will monitor the backfilled shaft using a so-called topping-up pipe.