Keeping Abandoned Mines Safe

It's not obvious from the peaceful scene at ground level, but a disused salt mine in Carrickfergus near Belfast is a real threat to nearby housing and businesses.

Since its working life ended at the start of the twentieth century, water has seeped in and is now eroding the pillars supporting the mine's roof.

There are more than 2000 disused mine shafts and adits - entrances or tunnels leading to mines - scattered across Northern Ireland and many of them are hazards to the public.

When the nearby Tennant mine suddenly collapsed in 1990, it threw debris high into the air and left behind a huge crater. Geologists think this one is likely to suffer the same fate within a decade or two, and anyone nearby when that happens will be in great danger.

The Geological Survey of Northern Ireland (GSNI) is using sensitive monitoring equipment down boreholes drilled through the mine to keep track of its slow progress towards inevitable collapse. In the meantime, the government has fenced off the area in an effort to keep local people out of harm's way.

Science writer and broadcaster Richard Hollingham talks to Geoff Warke of the GSNI and Bridget Harrigan from the Department of Enterprise, Trade and Investment, which is responsible for overseeing disused mines, about what they're doing to deal with the threat.