Gas and oil wells are a hazard for underground miners if they are mined into, with the threat of inundations, fires or explosions.

MSHA said wells drilled prior to state laws requiring exact locations may be present, but unmapped, within mine boundaries. Abandoned wells are particularly difficult to locate.

MSHA requires all oil and gas wells within the mining boundaries to be identified and accurately located in advance of planned mining.

MSHA's recommendations for locating oil or gas wells include:

Conduct a complete and comprehensive field survey and accurately plot the location on all mine maps;

Search well-owner information and databases;

Review and compare geographic information such as various generations of topographic maps and aerial photographs;

Search tax records, permits and other county or state databases for the history of royalty and other transactions regarding wells. Museums and historical sites may also be a source for records;

Use scientific methods and instrumentation such as magnetometers to locate the traces of iron indicating past drilling activity; and

Contact local residents and representatives of gas well operators for information regarding knowledge of pre-existing wells or drilling activity.