A Bit Of History Makes An Appearance

Crews work on ‘over excavating’ a mine subsidence in order to facilitate the repair

Oskaloosa, Iowa – Oskaloosa was built on mining and now rests upon those very mines. On Thursday local road crews handled a hole that developed in front of 1810 Kemble Drive, just east of William Penn’s new dormitory construction.

Wallace Greenlees, who is with the Iowa Department of Agriculture Soil Conservation Division, says that during the past few years he has seen this type of situation, or what is known as a mine subsidence, two or three times in the past. Greenlees said that not all sink hole type of situations are mine related, but said it’s his belief that the hole that developed on Kemble Drive was indeed related to an abandoned mine.

The Iowa Department of Agriculture Soil Conservation Division, Mines and Minerals Bureau has as relationship with The Office of Surface Mining, a Federal agency that has “Federal grant money involved that makes repairs like this possible, and the repairs have to be specifically related to mining. If it wasn’t part of mining, we wouldn’t be doing this.”

Repairs to the collapse involved digging the hole deeper, or ‘over excavate’ the subsidence with a track-hoe or excavator, then pushing rock that is up to nine inches in size down into the hole and compacting the rock into the dirt. This process helps create a stable bed to help prevent further collapse.

As the hole is filled with the compacted rock, the stone size gets smaller towards the top and then the street is eventually repaired.

Looking at a map indicating the location of old mines in the Oskaloosa area, it’s possible that the mine was named D.O. Steen and dates to 1895. Although, it’s entirely possible that the mine could be one of the ‘mom and pop’ type that were also common in Mahaska County at the time. Those kinds of mines were almost never mapped or well documented.