MANKATO — An environmental study on a proposed silica sand mining and processing plant just north of Mankato is finished. The public has until Feb. 20 to comment on the study.

Copy of report (large file 72 MB)

The Lime Township Board reviewed the study at its Jan. 8 meeting, and decided that it covers the topics — such as traffic, air quality, noise and water use — the board was interested in, Chair Karl Friedrichs said.

That decision cleared the way for the study to be officially published, on Monday, which will trigger the one-month comment period.

Jordan Sands, an affiliate of the Coughlan Companies, is seeking permits for the industrial sand mining facility, which could employ 40 people and 30 additional subcontractors. Uses for silica sand include the production of glass and concrete. It can also be injected into rocks to aid in the release of oil and natural gas, a process sometimes called “fracking.”

An open house about the study is slated for 7 p.m. on Wednesday at the Mankato Regional Airport.

“That is the best thing township residents can do, is come to that meeting,” Friedrichs said. Take a look at the 303-page report, and it’s easy to see why. Unless you’re the sort of person who doesn’t need to look up what “decanting” and “clarification” mean, you’ll need someone to help explain it.

When it was introduced last year, the proposal did not include on-site mining — the sand was to be mined from nearby pits in Mankato. But the study, called an “environmental assessment worksheet,” states mining will occur on 70 acres to an average depth of 90 feet.

The mines are not new; they have been previously used to remove the stone that sits on top of the Jordan Sandstone.

Airborne silica sand particles were a particular concern of residents at previous meetings.

The study notes that crystalline silica is not regulated by Minnesota or federal environmental agencies, though some states regulate it as an air toxin. Anti-dust measures in general, such as the “dust collection system” at the rail loading facility, will work for these smaller particles, as well, the study said.

It also said the facility will monitor the concentration of tiny particles for a 24-hour period every sixth day. If the particles approach the density threshold, testing becomes more frequent and, if it’s bad enough, continuous.

Because most of the land is either mined currently or was in the past, the study notes that there is little good habitat.

But there are about 10 acres of good habitat, and it may include three species — two snakes and a bird — that have been identified as needing some form of protection. The study also notes that four species of mussels and a paddlefish that live in Minnesota River are either threatened or endangered, but they are not described in detail because the project isn’t supposed to pollute the river.

The Loggerhead shrike has been designated as a threatened species since 1984, and the state is considering elevating this status to endangered, according to the report. The small songbird is known for impaling its tiny pray on thorns or barb-wire fences.

 The report said the project proposer has agreed not to remove shrubs or trees during the nesting season unless a biologist conducts a survey of the birds’ nests.

The North American racer is listed as a species of special concern, one status beneath threatened, according to the study. The western fox snake is not listed in the same system as the other two animals, but is noted as a “species of greatest conservation need” in Minnesota’s State Wildlife Action Plan.

The snakes are not protected by regulations, so there is no requirement to avoid these species. All three species are also found outside of Minnesota.

Water use, especially of aquifers, is another area of concern to residents.

According to the report, the sandstone to be mined is within the water table over the entire site. That means the water table will have to be lowered to allow drilling and blasting to loosen the sandstone.

While the system will require about 5,000 gallons of water per minute, the study said that 95 percent of that water will be recaptured and recycled.

This work will require permits from the Minnesota Department of Natural Resources. Other state agencies will also need to approve permits for other parts of the project.

After the comment period ends, Lime Township will decide whether more study is needed and, if it isn’t, whether or not the project is approved with conditions.

“That condition process is going to be probably the critical part of this project,” Friedrichs said.

It is the township’s chance, in other words, to set rules for the project to make it as harmless as possible.

Alternatively, the township could decide that no amount of conditions would be sufficient and stop the project entirely, but that could result in a legal challenge.