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presses met the capacity that was expect- ed. Forge commissioned and operated the plant for the first six months before t u r n i n g i t o v e r t o S o u t h e r n C o a l . T h e s t a r t u p w e n t w e l l , J e n s o n e x p l a i n e d . "The first cycle surprised everyone with t h e d r y n e s s o f t h e c a k e , " J e n s o n s a i d . "We had some problems with the pumps. T h a t h a s b e e n r e s o l v e d a n d t h e y h a v e been producing cake at the dryness and volume that they specified." A lot of thought was put into this installation considering the characteris- tics of the coal and the refuse and the desired quality of the cake, explained Pat Borreggine, vice president procure- ment, Forge Group North America. "There was testing that figured into the selection of the cloth," Borreggine said. "We bought the better cloth, which is critical as far as longevity and opera- tions of the plate frames. We had antici- pated, or were given the expected moistures for the cake, and we exceeded that by an additional 5%. That allowed us to reduce the cycle times and pressures." Lessening the cycle times decreases the wear and tear on the machine. The Development Curve Believing that the technology could benefit coal operators, McLanahan has been work- ing with these machines in the field for a while. Their first unit at Sunrise Coal was a recess chamber machine purchased from an Italian company. "After that installation, McLanahan worked with a second Italian company before deciding to pursue our own design that we could support ourselves with local parts and service." McLanahan now has five of these machines operating with more starting this year in other applications (aggregates and industrial min- erals). The units at Bishop are the first two operating in coal. "Six additional McLanahan presses are due to be coming online in coal applications in the next six months," Jenson said. "Anywhere that chemical or handling costs, permitting or compaction is an issue, we are seeing lots of interest." Mine operators have been fairly vocal a b o u t t h e h e a d a c h e s a s s o c i a t e d w i t h permitting and permitting an impound- m e n t o r e x t e n d i n g t h e p e r m i t f o r a n impoundment. The filter press offers a closed-loop solution. The cake simply n e e d s t o b e d r y e n o u g h t o m e e t c o m - paction requirements. After working with these systems, McLanahan discovered how it could improve the system using standardized local parts. Probably the biggest selling point about the McLanhan filter presses is that they are easy to install, integrate and operate, and they provide an efficient, cost-effec- tive operation. The company's Smart Hydraulic system controls operating pressures and positions for fast, precise opening and closing. With pressures of 225 psi to 870 psi (16 to 60 b), the press can dewater even the most difficult sludge, including those with a high clay content. The PLC-controlled press has many available cake thicknesses or mem- brane plates for the driest possible cake. Ultimately, it depends on the specifica- tion for the dryness of the filter cake. d e w a t e r i n g f i n e s c o n t i n u e d March 2014 www.coalage.com 39 CA_pg38-41_V3_CA_pg46-47 3/11/14 2:46 PM Page 39