The conversion of hundreds of acres along the highway south of Shakopee into mining and blasting is creeping toward reality, amid plenty of anxiety among the public and even some officials.

"I have a hard time believing these microparticles will be confined to the [mining] area alone," neighbor Beth Walden of Louisville Township told the Scott County board last week. "We own a business, too, but we walk carefully and make sure we aren't jeopardizing the lives of others just for our own profit."

The county's experts acknowledged they are venturing into unfamiliar territory, with a certain number of unknowns. But they stressed that they plan to watch carefully how it goes and have insisted upon remedies if there are signs of trouble.

Explosions are expected to take place three to four times a week as miners attack the sandstone in the process of turning it back into sand, Kate Sedlacek of the county's environmental health department said. But she added:

"Seismographs will verify the vibrations, and we'll have pre-blast surveys checking out structures before and then after, and the developer will take care of any structural damage caused."

Two sites along Hwy. 169 could be mined for the kind of silica sand used in "fracking" to extract oil:

•The Great Plains site, a small one about halfway to Jordan that was mined in the 1980s, could be operating by November under a green light, with conditions, from the county and townships.

•Merriam Junction, an area of nearly 1,000 acres closer to Shakopee, is big enough to need a full-scale environmental review that's expected to last into 2013.

The study of the latter will serve as lefthanded preparation for the former, as it will be well in hand before Great Plains actually begins operations, officials said.

An article in the latest county newsletter describes Scott County as experienced with silica sand based on those earlier operations and says the situation is less heated than in some Minnesota counties, with no hint of the demands for moratoriums that other counties are seeing.

But it was clear from testimony last week that sour memories remain from those earlier experiences. And the county's own draft environmental statement is careful to offer no guarantees:

When breathed in, "silica dust is a known carcinogen," it says, meaning it can cause cancer. "The proposed mining operation will result in increased risk of exposure to this carcinogen. There is an unquantifiable potential for long-term adverse health impacts due to exposure to respirable silica dust. The extent and significance of this exposure is directly related to the practices employed by the mining operation to control releases of respirable dust. The submitted mining operational plan demonstrates conformance to best management practices for the reduction of fugitive dust. A monitoring and mitigation plan has also been provided."

Witnesses questioned whether anyone is going to want to build anything in the vicinity of a mine that sees big blasts during the week, including Saturdays.

Cy Wolf, of the Sand Creek township board, said his group is going along with the Great Plains work but added that the "nuts and bolts will be significant" and haven't all been worked out.

John Weckman of the Louisville Township board said his group is worried. While the county's staff has been "great to work with," he said, "we definitely do have concerns on this and we want to make sure the county backs us when [issues arise in the future] and makes sure we get action."

County Commissioner Dave Menden said it's a good sign that owners of the property are "homegrown," making him think that "you people should be able to work together." But he added: "Go ahead and make a profit, but these people have rights, too."

David Peterson • 952-746-3285