Pit & Quarry, November 2016

WASHING CLASSIFYING Pumped UP When a slurry pump proves insufficient Short Mountain Silica discovers a high pressure alternative that meets the demands of its ultra fines recovery system J immy Smith noticed something was wrong with the ultra fines recovery system at Short Mountain Silica Eventually Smith pinpointed a two monthold pump as the problem The operation disassembled the pump three months into its use confirming Smiths suspicion We noticed the impeller was almost completely gone says Smith quality control manager at the operation in Mooresburg Tennessee Short Mountains minus 400 mesh silica had eaten away at the metal The operation could have replaced the existing pump with another of the same model Smith says but Short Mountain which operates a plate and frame filter press likely would have encountered the same predicament in another three months or so Instead Smith sought a longer lasting solution We decided we were going to need a high pressure pump Smith says So Smith turned to Paschal Associates which presented a Schurco Slurry pump as a solution In Short Mountains application a pump has to generate a lot of pressure to force water through mud says Tom OBrien sales engineer at Paschal Associates A pump in a typical application might develop in worst cases 100 lbs of pressure Typically though when BY KEVIN YANIK Short Mountain Silicas 4 in x 3 in x 20 in high head slurry pump delivers higher pressures because of a unique impeller geometry according to Schurco Slurry the pump manufacturer pumping slurries it may be 45 to 65 lbs of pressure and a lot of times less than that In Short Mountains case a pump providing 185 lbs of pressure is now being utilized Short Mountains process is a batching process OBrien says The plate press is filled up with mud by this pump and the pump pushes mud into the press and thereby water out of the press DEVISING A SYSTEM The pump is one key component in Short Mountains ultra fines recovery system which was constructed in three phases to eliminate the costly task of digging the operations waste stream from three settling ponds Cyclones and a dewatering screen were added in the first phase of the project several years ago That equipment captures about 90 percent of the operations plus 325 mesh material OBrien says reducing the amount of solids reporting to settling ponds You pull out some of the solids mechanically so you dont have to dig it out afterward OBrien says A second phase of the ultra fines recovery systems development involved adding a clarifier to achieve solid liquid separation Were separating the mud from the water right there OBrien says The clean water goes back into the water system and is reduced This is a means mining operations have to recycle clean water so theyre not constantly pulling water from the environment The mud pumped out of the clarifier is then pumped to a filter press the third stage where it is dewatered But the pump breakdown Short Mountain experienced at that stage made the entire system less efficient That is until the Schurco H Series 4 in 30 PIT QUARRY November 2016 pitandquarry com PHOTO COURTESY OF JIMMY SMITH