Pumps for the mining and processing industries
I don’t have to tell you that the mining industry is an extremely important part of the Canadian economy. National Resources Canada reports that in 2012, mining contributed approximately $63 billion to the Gross Domestic Product (GDP), representing 3.9% of the Canadian economy.
In that year, mineral exports accounted for 20.2% of Canada’s total exports. Canada is also a giant in the global mining economy: Canadian exploration, mining and allied industries operate in over 100 countries, with cumulative assets worth $147 billion outside Canada.
Managing water resources efficiently is an increasingly critical part of mining operations, especially when mines are located in dry and/or environmentally sensitive regions.
Mark Sidon, mining specialist and regional manager for the Canadian arm of pump-maker KSB Canada points out that “awareness has increased among mining companies about the importance of conservation, reclamation and preservation of water in a mine – and that calls for more sophisticated pumping solutions and pump systems”.
Reclaimed Water
Increasingly stringent environmental protection requirements mean more emphasis on water processing – especially for reclaimed water that is being returned to ponds or lakes.
Tailings water treatment for mining and mineral processing operation often involves the handling of water with significant amounts of abrasive suspended solids. Pumps for dry-well installations are available with highly wear-resistant hydraulic components that help ensure longer service lives and reduce maintenance requirements under arduous operating conditions.
Water Transport
Mining operations can require the transfer of large volumes of service water over significant distances. There are a variety of high-capacity pumps available with proven success in mining water transport applications.
The key selection criteria are reliability, longevity and the overall energy efficiency of the installation. Since these pumps typically run continuously for long periods, energy costs become a significant element of the total cost of ownership. Increasing capital expenditure for a more efficient system can significantly reduce operating costs, resulting in a lower total cost of ownership for the entire system.
To optimize a system’s efficiency, it is important to look not only at pump and motor efficiency, but also ensure a close match between the required duty point of the installation and the best efficiency point (BEP) of the pump set.
Oil sands
The SAGD (Steam-Assisted Gravitational Drainage) process has emerged as an important technology for the extraction of bitumen from underground oilsands deposits.
This in-situ extraction technique enables access to deep deposits while reducing the environmental impact of large-scale open-pit excavations. Here, super-heated water is pumped through pipes into the heart of the oilsands deposits.
The hot water flashes to steam and heats the bitumen, making it sufficiently fluid to be pumped back to the surface through extraction pipes that run parallel to the steam-injection pipes. Special high-pressure, high-capacity pumps are required to provide large volumes of the high-pressure, high-temperature water needed by this process.
Slurry pumps
The processing of ores also requires transport of large quantities of water, frequently in the form of slurries. Pumped slurries are an efficient method for transporting mineral particles from mine to processing plant and through the ore separation processes. Slurry mixtures are also encountered in mineral processing facilities and in refining processes such as the separation of bitumen from sand and gravel in the oilsands.
Water/mineral slurries are extremely abrasive, wearing on pumps and associated equipment. Specialized slurry pumps are designed and built to provide reliable service in mill circuits, grinding circuits and the flotation circuits.
Slurry pumps differ from solution pumps in a number of important ways:
Since the solid particles in slurries are highly abrasive, wear of internal pump components is a concern. Pump components are typically made from highly abrasive-resistant materials such as extra-hard white iron or martensitic steel alloys.
For some applications, pump linings made from natural rubber or other polymer materials are used to reduce wear.
Wear from abrasive suspended solids tends to be more severe when flow velocities are high. Therefore, slurry pumps are often designed to run at lower speeds than water pumps. Consequently, slurry pumps often require gearboxes between the pump and motor and are often considerably larger than water pumps with equivalent capacity and head ratings.
Slurry pumps are designed with easily accessible casings to simplify replacement of high wear components such as suction plates and impellers.
Reducing mine down time with quick and efficient pump maintenance directly affects the profitability of any mine.
The impellers used in slurry pumps are designed for wear-resistance and to provide generous free passage for large solid objects.
Properly configured slurry pump systems can be a cost and energy-efficient way to transport ore to and through processing facilities. Water used for mineral slurries can be almost completely recovered and reused in this cycle.
Service and Support
The pumps used in mines and mineral processing facilities face harsh conditions. To help ensure reliable operation and long service life under these conditions, it is important to select the right pump for the job, install and commission it correctly, and then implement suitable preventative maintenance procedures.
*Mike Blundell is President of KSB Canada
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