A US NATIONAL ACADEMY OF Sciences dam safety study team has concluded that it is difficult to say whether coal mine waste impoundments in the nation are safe.

The study team expressed concern that mine maps showing the location of underground mines beneath many of the impoundments might be inaccurate.

The year-long study into coal mine tailings dam safety was ordered by Congress in 2000 after the spill of toxic coal slurry from an impoundment owned by Massey Energy, in Martin County, Kentucky. On 11 October 2000, more than 1.4B litres of slurry from the Massey operation broke into underground mine workings beneath the impoundment and later poured into two tributaries of the Tug Fork of the Big Sandy river, affecting fish and drinking water supplies as far downstream as 97km.

In the 281-page report, the committee called for new regulations and additional inspection of the 700 impoundments throughout the country’s coalfields.

The National Research Council committee emphasised in the report that it only considered specific issues related to dams and not broader matters about the coal industry’s environmental and community impacts.

The academy’s study noted that there have been other dam accidents since the 1972 tailings dam failure at Buffalo Creek which killed 125 people and left 4000 homeless. The study said the majority of incidents involved failure in the basin area, indicating the likely causes as inaccurate mine maps and inadequate characterisation of the basin area.