The Wisconsin Department of Natural Resources reports early test results find no harmful chemicals after a spill of sludge last month.  The problem started at the Hi-Crush mine when a bulldozer slid into a pond in western Wisconsin.  People trying to rescue the equipment operator emptied 10-million gallons of water from that pond at a fracking operation.  Thick sludge drained into the Trempealeau River and eventually reached the Mississippi.  No fish kills have been reported and oxygen levels are good.  The preliminary test results show “no immediate toxicity.”