Police in Brooklyn Center have arrested seven protesters at a conference on silica sand mining...including four Winonans.

The protesters were arrested Wednesday after they climbed on top of a bus that was scheduled to carry conference participants to a tour of silica sand mines in Wisconsin.  The protesters unfurled banners that read "Stop frac sand mining" and "No right way to do something so wrong."
 
The Minneapolis Star Tribune reports the seven Catholic Worker volunteers from Winona and Des Moines, Iowa, were charged with unlawful assembly, booked  and released. The seven spent more than 90 minutes atop the bus.
 
Western Wisconsin and southeastern Minnesota are rich in silica sand deposits. The sand is used in the hydraulic fracturing process to produce oil and natural gas.  Critics say mining the sand can produce harmful dust, increased truck traffic and lower property values.