Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr
Issue link: https://emj.epubxp.com/i/131325
PUMPS & PIPING FLSmidth points out, this causes particles to be trapped and ground between the two, decreasing the wear life and efficiency of the pump. The newest addition to the millMAX product family is the Ultimate Mill Discharge (UMD) pump, which is designed specifically for the most abrasive mill-discharge applications. The UMD design minimizes hydraulic turbulent wear within the pump while still maintaining all of the advantages of the suction-side sealing system. Meanwhile, FLSmidth Krebs' Technegate knife gate valve is a bi-directional, packingless, on-off slurry knife gate valve that has been designed for harsh service. Its open body design ejects material from the bottom and prevents the gate from jamming. Available in sizes from 3 to 30 in. (76 to 762 mm), these valves feature a stainless steel gate running within a cast ductile iron body, while the sleeve design allows for unobstructed full-port opening, the company says. Pinch-valve Design Minimizes Internal Erosion U.S.-based Red Valve Co. has been building valves since 1953, when it developed the pinch valve for the world's first coal slurry pipeline. Since then, the company says, use of its equipment has spread world-wide, with its valves featuring fullport openings, non-clogging designs and the use of abrasion-resistant materials in their construction. Red Valve claims to be able to offer solutions to every valve application found within a tailings-disposal system, for instance, with both its pinch valves and Flexgate valves finding applications for this use. For slurry applications, the company points out that rubber is tougher than metal, so in the wide-open position, there is virtually no wear or turbulence on the sleeves of its pinch valves. Unlike the flow patterns in conventional valves, which create a deflection that causes wear, the flow pattern in a Red Valve pinch valve is streamlined even when throttled. Red Valve adds that since the operating mechanism is isolated from the flow, a manual pinch valve can be left in the open or closed position for years without affecting the operating torques, which remain constant. Meanwhile, its Flexgate valves are commonly found on tailings systems, especially in larger-diameter sizes. The Flexgate valve provides the best features of a pinch valve and a knife gate valve. A knife blade 74 E&MJ; • APRIL 2013 passes through two full-port elastomer seats, opening or closing the valve. Pinch valves are also used for controlling the level in thickeners, where the underflow contains a high solids content that quickly destroys ball, butterfly and plug valves. Red Valve says that its pinch valves have a patented cone sleeve trim that is sized to match any application's exact control requirements, so its pinch valves provide precise repeatable control across a wide range of pressure and flow conditions. Multi-stage Centrifugal Pumps for Mining At the heart of a GE Oil & Gas Surface Pumping Systems (SPS) unit is a multistage centrifugal pump that can typically handle up to 125 liter/s (2,000 U.S. gallons/minute) and discharge pressures ranging up to 410 bar (6,000 psi). Offering a low surface profile coupled with quiet vibration-free operation, SPS units are available in electric-, gas- or diesel-powered versions. Their modular design makes the units suitable for a wide variety of applications, including mine dewatering and leaching operations. GE says its SPS pumps provide a versatile, low-maintenance alternative to many multi-stage split-case centrifugal, positive displacement and vertical turbine pump models. SPS pumps are delivered to the job site pre-assembled. The frame assembly is pre-wired with instrumentation and cabling, so the suction and discharge flanges and power hookups are typically the only connections needed. The company notes that effective water management is critical in mining and saltdome leaching operations, and claims that its SPS pumps provide low initial and whole-life costs, high pump efficiencies, minimal routine maintenance, flexibility for changing operating conditions, and easy repair. They are available as portable skid-mounted units, trailer-mounted units or multiple pumps in fixed installations at main pump stations. SPS units are used in many cavern leaching and/or formation jetting (borehole mining) applications. In leaching processes, SPS pumps are frequently used to circulate water in a salt dome, with the cavern formed then being used to store oil, natural gas or other materials. The storage process also requires properly matched SPS injection pumps, GE points out. According to GE, the SPS pump is designed for years of trouble-free operation. There are no V-belts or packing to service, and routine maintenance consists of a quarterly lubricant change and component check. GEÕs surface pumping systems for mine dewatering, as well as salt dome leaching and injection operations, are multistage centrifugal units available as portable skid-mounted units, trailer-mounted units or multiple pumps in fixed installations at main pump stations. www.e-mj.com