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
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D E W AT E R I N G Selecting a Reliable Dewatering Pump for Mining Applications It's important for pump buyers to understand their requirements for casing materials, port sizes, power options, features, maintenance needs and total cost of ownership prior to making a purchasing decision By Ken Boyce According to a recent Research and Markets report, the U.S. metals and mining industry grew by 5% to $201.5 billion between 2007 and 2011. Research and Markets anticipates even faster growth—around 6.3%—will drive the industry's revenues to $273 billion by the end of 2016. As the U.S. mining industry grows, so does the need for reliable dewatering solutions. Standing water is an issue for miners in most regions, and contractors The Ingersoll Rand Pit Boss air-operated diaphragm pump has a unique exhaust check valve to prevent water and contaminants from entering the air motor system, enabling it to function while fully submersed. 36 E&MJ; • AUGUST 2013 rely on diaphragm pumps to clear the site before they send in employees and equipment. Most mining contractors bid projects on flat rates, and it is critical that the project remain on schedule to stay within budget. If a pump breaks down during the dewatering process, it causes production delays, which quickly drives up project costs. Evaluating Diaphragm Pump Options Diaphragm pumps are available in a variety of materials, port sizes and power options. When selecting a diaphragm pump for dewatering applications, buyers should look for features that increase its reliability and durability to help prevent breakdowns. Diaphragm pumps' casings are made from metallic or non-metallic materials, and some of the most common include aluminum, stainless steel and polypropylene. If mining customers are uncertain about the composition of the standing fluid, they should use a pump with an aluminum casing because it is corrosion-resistant and compatible with a wide range of fluids. In addition, aluminum is lightweight, which makes it easier to transport around the site and durable enough to withstand rock and sediment on location. The pump's design affects its flow rate and portability. Most diaphragm pumps are offered in 1-1/2-, 2- or 3-in. (38-, 50.8- and 76.2-mm) ports to handle moderate to heavy flow rates, which vary by application. It takes crews longer to clear standing water using the 1-1/2-in. port, but the pump is more compact and lightweight than the 3-in. model, to facilitate transportation. Diaphragm pumps designed with comfort-grip handles are easier to move— and more ergonomically friendly—than the pumps without handles, which require workers to lean over and grab the pump by the manifold. Mine operators and contractors have the option to use air- or diesel-operated pumps. Air power pumps meet the stringent requirements of hazardous environments, where electrical or diesel-driven units are not considered suitable. If contractors are uncertain whether the standing water contains traces of diesel fuel or combustible substances, they should opt for an air-operated diaphragm pump, which meets applicable codes and grounding requirements. Selecting Features that Increase Reliability Buyers can choose from generalpurpose diaphragm pumps or dewatering pumps designed specifically for mining applications. Either option can be used to remove standing water from a pit, but dewatering pumps are specifically designed to prevent the most common pump issues, which include clogging, stalling, centering, tipping and air blow-by. Most clogging issues occur when foreign particles get trapped in the pump during the dewatering process. If this occurs, the pump continues to cycle without pushing any water through the hose, causing production delays. When making a purchasing decision, it is important to select a pump with a removable screened inlet that prevents rocks and debris from entering the system and keeps it flowing smoothly. Removable screened inlets also give operators the flexibility to take off the filter and attach a suction hose to the inlet, instead of submersing the entire pump. Stalling, centering and air blow-by commonly occur when operations use diaphragm pumps designed with balanced valves, which allow air to leak www.e-mj.com