Friday 14 June 2013

Iowa sinkhole linked to nineteenth century mines.

A three meter wide, three meter deep sinkhole that opened up in Runnells, Polk County, Iowa, around the beginning of June has been linked to abandoned nineteenth century coal workings in the town by the Iowa Department of Agriculture’s Mines and Minerals Bureau. Engineers plan to begin excavation work at the site of the sinkhole, close to the home of local resident Bob Borg, on Friday 14 June 2013. The appearance of the hole necessitated the removal of a pole supporting power cables which was in danger of falling onto Mr Borg's house.

The Runnells sinkhole. Des Moines Register.

The State of Iowa required all mines to be documented and mapped from 1902 onwards, but mining began around Runnells in the 1880s, fueled by the demand for coal for paddle-steamers on the Des Moines River. A large number of mines popped up in the area at this time, many of them small, family-run operations with no effective record keeping. 

Sinkholes have been a longstanding problem in the eastern part of Runnells, though there have not been any major incidents leading to loss of life or property. Engineers from the Mines and Minerals Bureau will attempt to ascertain whether this sinkhole is the result of an abandoned mine, or another cause, such as an old well or septic tank. If an abandoned mine is found then the plan is to infill it with crushed limestone as far as possible.

The approximate location of the Runnells sinkhole.

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