By Dar Danielson (Radio Iowa)

Marion County has learned more about the large sinkhole that has become an attraction after opening up in the county.

County Public Information officer Emily Feagins says borings from the Department of Agriculture have confirmed a coal mine is not to blame.
“There was a very minimal amount of coal in the layers. So right now, we have noted out that it is not coal related,” Feagins says. She says the sinkhole could be related to limestone mining — as there is a mine north of the area, but the maps don’t give a clear picture of what’s going on.

“Mining maps just aren’t simple anyways, when it comes to locating on the top of the surface where they are below the surface. So that’s another thing that we’re kind of working on, where does it match up on top of the surface to where they are below the surface,” she says. Feagins says they want to do some more work to try and determine if a limestone mine could be the culprit.

For now, they are not going to try and fill in the hole. “Because there is the potential that this sinkhole could keep expanding that you know, it could get bigger. So it doesn’t really do us any good yet to start filling it in if we don’t know still, what’s causing it,” she explains. She says they want to be sure they have a solution that will work.

“If we fill it in and we haven’t gotten to the bottom of what’s caused it, then it could continue to sink and then at that point in time, we’re just wasting dollars, manpower, equipment on filling something and that is going to possibly concave again,” Feagins says. The sinkhole is in a field, but expanded and there is a void under a nearby road, which could collapse unless they take the right action.

The sinkhole was first reported April 14th.