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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80 E&MJ; • DECEMBER 2015 www.e-mj.com While many mining applications rely upon the delivery of high-pressure water requiring powerful pumps and heavy-duty pipework, elements of an effective water management system can often operate successfully without the need for pumps. Tailings management and heap-leach processes can sometimes be configured to use "cost-free" gravity flow, along with general rainwater or storm water drainage management as non-pressurized sys- tems. However, it is common to see pumped-pipe systems specified for such applications, leading to unnecessary expenditure on pumps and high-specifi- cation pipes themselves, as well as on the ongoing maintenance of the equip- ment. Similarly, higher-pressure pipes are frequently specified where there is no benefit in doing so. Fully certified, high-quality, high-density polyethylene (HDPE) pipes designed for gravity-appli- cation pressure grade would provide all the required corrosion and abrasion resistance required of mining applica- tions without the added expense of a higher rating. All pressure pipelines carry a Pressure Nominal (PN) rating, which indicates the pressure (in bars) the pipe can support when the water inside is at 20°C. For all too many gravity applications, PN10 or even PN16 is frequently specified, when in actuality the water or slurry within is drip-fed, meaning a less expensive gravi- ty pipeline will be more than sufficient for the purpose. Pump manufacturers typically esti- mate that up to 90% of a pump's life- time cost is attributed to energy usage, wear and parts, making them one of the most expensive components on a mine site and even more costly if they are specified when not truly required. Poorly maintained pumps or those work- It's common to find water management strategies at mines that are based on expensive high-pressure pumped systems when more economical gravity flow would be suffi- cient in many cases, says U.K.-based plastic pipe supplier Polypipe. O P E R AT I N G S T R AT E G I E S Gravity Flow vs. Pumped Systems: Are You Overspending on Pipes and Pumps? Mine-duty plastic piping and water management systems present options to reduce costs for mine operators By Phillip Wood