Media Release
Solid Energy to undertake further work to control underground fire at Strongman Mine
16 October 2008
Solid Energy is planning further work at the former Strongman 2 Mine near Greymouth to restrict an underground fire. The work, in an area called Harrison’s Ridge, is also expected to improve the stability of a slope above Doherty Creek.
The West Coast Regional Council has granted consents enabling Solid Energy to undertake the work, which is expected to take four months. Along with a quantity of coal, approximately 35,000 cubic metres of rock will be removed from the ridge area as it is shaped into steps. During the work there is some potential for rock to fall into the valley and creek bed. Any impact on the creek will be assessed and, where necessary, remedial action will be taken.
Mark Pizey, Solid Energy’s National Environmental Manager, says the fire at Strongman is fed by remaining coal deposits and without that fuel source it would naturally go out. By cutting out a potential fuel source under Harrison’s Ridge, the planned work will also make the escarpment more stable.
“By slowly consuming the edge coal along the cliff, the fire has been causing that area to subside, exacerbating the escarpment’s natural instability,” Mr Pizey says. “Removing a section of remaining edge coal should restrict the fire’s ability to migrate any further west and to cause subsidence. In the area of the actual work, we plan stepped benches that will be much more stable than the present situation.”
The underground fire was first noticed in August 1996 and Solid Energy’s programme of active management has included covering areas where the fire was close to the surface with more than 200,000 tonnes of overburden, the injection since 2004 of approximately 100,000 dry tonnes of clay and cement kiln dust mixed with water to create an underground grout curtain, an extensive monitoring programme and other work to remove coal ahead of the fire. Strongman 2 Mine closed in August 2003.
Solid Energy has been working with an Australian specialist in mine fire management to further develop options for the Strongman fire and has been discussing these with the Regional Council. As well as cutting out the coal margin and reshaping Harrison’s Ridge, options under consideration include stopping the remaining open portal to cut off oxygen supply and to gauge the potential to flood the old workings.
