The report said the Guza Pit, which is located across the Mississippi River from Winona, has been shut down as it was found to be operating without a permit and had been dumping polluted wastewater into an unlined pond.

According to the report, operators of the county in which the mine is located require water containing certain chemicals such as polyacrylamide, to be dumped into lined ponds. The Guza Pit is located near a stream that flows into the Mississipi River. Polyacrylamide, the report said, contains a neurotoxin that is linked to cancer and infertility. You can read the rest of the report here.

The Guza Pit is operated by Superior Silica Sands which is part of Emerge Energy Services which produces 4.4 million tons of sand a year.

Read more about frac sand minning here.