Pit & Quarry, February 2017
FINES RECOVERY For optimum fines management at the wash circuit the Aggredry dewatering washer is engineered with a fines recovery system where minus 025 mm sand collects in an under f lume and is reintroduced back into the sand screw via a water jet This patented technology saves up to 3 percent of the material from a waste pond Larson says fines management is a major concern We were concerned whether the water jet on the system should run back into our pump or back into the sand screw he explains Superior Industries said that it would be easier to manage the fines with the water jet going back into the sand screw and they were right In the past Larson says Wissota had to be very selective on what could be run through the wash plant If we hit a dirty spot in the pit we werent able to get enough fines out of the sand With our new system we can process dirtier material and still manage the fines on the wash end of the plant This gives us more throughput without having to be so particular about the material coming from the primary circuit Thats a big advantage as the face of the pit is always changing he says adding his operation crushes 18 million tpy with about 15 million tpy going through the wash plant Larson says his operation sees very little waste The fines that are washed out of the Aggredry system go to a set of cyclones where material between minus 200 mesh and 400 mesh is processed out stockpiled and sold as bedding material for nearby livestock facilities Any material that is minus 400 mesh is treated within a clarifier The dry material is easy to convey even when the stacker is elevated to its full height allowing us to manage our stockpiling far more effectively CHRISTOPHER LARSON WISSOTA SAND GRAVEL flocculant system with the solids being pumped into a retaining area and used for reclamation COST PER TON SAVINGS Prior to the purchase of the new Aggredry system Larson conducted considerable research into the various sand washing solutions on the market Compared to the use of cyclones and pumps which can produce similar results in some applications he especially liked the reduction of horsepower The Aggredry system at Wissota Sand Gravel features twin 60 in finematerial screws combined with twin high frequency dewatering screens pitandquarry com February 2017 PIT QUARRY 57
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