Photos taken of the silica sand mine and processing site at CTH DD and STH 64 in the Town of Auburn on October 7, 2011 by James Torseth. Note visible emissions from sand piles. Photographer noted "Upwind of the site the sky was clear. Downwind of the site there was a whitish gray haze extending for a mile or more."
Photo of Superior Silica Sand mine in Bloomer, WI on November 5, 2011 (from Mary Kenosian).