Sealing the Windmill Well

Last week the windmill well was officially sealed and abandoned. The truck-mounted well rig raised a mast so the long lengths of pipe could be pulled out. The first one to be pulled had the original old pump. It hadn’t been used in more than 20 years because rural water came in when we moved back to the farm. The well was drilled in the 1940s and the windmill was moved on to the location from a shallow well. In the 1980s, the windmill fell; after that an electric motor ran the pump.

Each section of pipe pulled out of the well was about 20 feet long. The rig lifted the string of pipe, each section was unscrewed, and then laid out on the ground. There were about 10 or 11 sections of pipe, so the well was just over 200 feet deep. That’s deeper than most of the old wells in this area, but it’s about half as deep as I thought Dad had told me. Consequently, I’m not sure if the layer producing water (“aquifer”) was a glacial deposit or a deeper sandstone called the Dakota Formation.

After the pump and all of the pipe was pulled out of the hole, a slurry of bentonite was pumped down into the empty casing. Individual bags of the expanding clay were mixed with water and the slurry was pumped into the well through blue PVC pipe. The idea is that when the “grout” sets up, the well is sealed so that surface water can’t contaminate the subsurface water in the buried aquifer. This formal sealing procedure is particularly important in the southeastern part of Minnesota where buried limestone aquifers are more easily polluted by surface water. Although it’s less critical here in southwestern Minnesota, all abandoned wells in the state have to be accounted for on every parcel of land that’s sold.

So, here are the before and after pictures of the top of the well. I’m not sure what we’ll do with that cement remnant. Maybe just leave it as a monument to the memory of the windmill. The decision to abandon the well was based on water quality. The well water had high sulfur content; one of our relatives used to take a jug home to use as a laxative. It also was very hard and had a high iron content that stained things a rusty brown. The rural water is probably better for both cattle and people.

About Lone Tree Farm on Kanaranzi Creek

Recovering academic, earth scientist in phased retirement, farm manager by default, son, husband, father, grandfather.
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