Officials will be digging into a sinkhole to see whether it leads to an abandoned mine under the Polk County town of Runnells.
A state environmental engineer, Mike Bourland, told The Des Moines Register that there are mines in the area.
The sinkhole made its debut about two weeks ago in the front yard of Bob Borg. It was nearly 10 feet deep and around 10 feet wide, gaping just a few yards away from his house. The soil had eroded around a power pole, which was taken out.
Environmental engineers plan to dig into the sinkhole on Friday.
Runnells Mayor Ron Tate says several sinkholes have appeared over the past 20 years in a field on the east side of town.