CALEDONIA, Minn. (WKBT) -

Houston County officials want to keep new frac sand mines out of the area.

The county commissioners extended a moratorium on adding new operations through March of 2015. Now, they're asking state officials how to make it permanent.

One of the commissioners says the county tax base is too small to handle the impacts to the infrastructure like the roads.

They're also worried about the effects it would have on the water supply and the environment. "We don't know the adverse effects of this yet, we don't know what the future may bring. Our biggest concern is we don't want to jump in too soon and 10 years from now wish we hadn't. We'd like to take a very cautious approach," said County Commissioner Justin Zmyeswki.

The commissioner does not currently know of any corporations that are interested in sand mining in the county.