Pumps play an integral role in mineral processing plants, essential in moving material from one point to another.
In the world of hard rock mining, the crucial job of pumping large amounts of solids or particles from one location to another is done with the aid of water or other solutions.
The speed, efficiency and reliability of pumps are paramount to the smooth running of multiple, interconnected systems at an operation. A whole host of factors determine pump selection and system design at a mine site, including client preferences, site applications, nature of the solids and fluids, distance, height and gradient, to name but a few.
Robust pumps are stable while in use, discharge solids properly and are easy to maintain, thereby minimising blockages and supporting safe systems of work.
The Australian Mining Review spoke to Kelair Pumps Australia regional sales manager Michael Charnley about tackling the issues of pump efficiency, reliability and packaging at Australian mine sites.
Pumps In Mining
Application for mining pumps can be categorised into centrifugal (for slurries), dewatering or processing plants. Kelair Pumps specialises in pumps for mineral processing plants and hard rock mining such as copper, lithium, gold and nickel.
“Kelair is heavily involved in gold processing plants where we design systems involving suction pumps, multistage pumps, dosing pumps, acid pumps and all other types of chemical pumps,” Michael said.
“With the dewatering process, we offer self-priming pumps sets, borehole pump sets and line shaft vertical turbine pumps to move large amounts of water.”
Understanding the application of the pump or a series of pumps at a mine site comes down to knowing the nature of the fluid and the solids, as well as working out the system or friction head losses including distance, gradient and height.
Pipe length and size are useful when calculating the flow pressure or pump head. Pressure and head are not typically the same thing. Head, measured in metres per head, is used to measure a centrifugal pump’s energy, as pressure can fluctuate when the weight of the liquid changes.
Corrosion
Where there is heavy pumping of water or solutions, the inner linings of the pumps are subject to corrosion.
“A lot of mining processes depend on large volumes of water,” Michael said. “Water is probably the thing that gets pumped the most and many of these pumps are subject to corrosion.
“If a fluid is corrosive, there are a couple of options including the use of exotic alloys or internal coatings. There is a much lower cost and much shorter lead time with internally coating a pump versus getting a new pump made from an exotic alloy.
“If someone has to replace something in a fairly short period of time, replacing internal coatings would be the best solution.
“For underground mine dewatering and pumping solutions that will not corrode, we see AODD technology as widely accepted.
“Sandpiper air-powered diaphragm pumps have both ball and flap-check valve pump technology available in an all non-metallic body, offering longevity of unit.”
Sandpiper plastic-bodied diaphragm pumps will last longer than their metallic model counterparts in corrosive environments.
Seeing a need globally for a true solids handling pump that is suitable for use in harsh corrosive environments, Sandpiper developed the HD20F 2” non-metallic flap valve pump.
Designed around the existing metallic Sandpiper Heavy Duty HDF2 with proven air system, diaphragms and flap valves technology, the HD20F has flap-check valves that allow access to the pump without needing to dismantle the pump.
It also allows large solids up to 44mm to pass through the system without causing any damages to the pump.
Access ports on the side are unique to this Sandpiper design and not found on any other dewatering pump on the global market.
Blockages can be cleared easily and the pump put back into operational service without the need to remove it from site.
Another feature is the very low air consumption compared to some of the major brand 2-inch plastic pumps.
Comparative testing has shown that the Sandpiper HD20F consumes 25-40% less compressed air than other brands of pumps, leading to significant energy and dollar savings.
Reliability, Efficiency And Durability
Efficiency is about getting the most work done for the least possible power. An efficient pump is usually a reliable pump.
All pumps have a “best efficiency point” and it is imperative to get the unit to operate at the point where it should operate. Reaching this best efficiency point will, by its very nature, create a more efficient product.
“An in-depth look at the application of the pump and its uses requires careful consideration of the following: what does the pump have to do, where will the pump spend its time, how will be manage the external factors and environment,” Michael said.
“Answers could be the installation of variable speed drives on the pump to achieve multiple flow rate and pressures. It depends on how much power you are going to use and how often or for how long.
“The more we can spend talking to our clients about what exactly their pumps are going to do, the more likely we are going to get an efficient solution. It’s really about sizing the pumps properly for the job. That’s what really makes the difference to efficiency.
“So having a pump where most of the energy is going into the fluid is what we really want to happen and that way we ensure an efficient pump, a pump that people will be happy with.”
Unreliable pumps are expensive. When pumps are running at a point where most of the energy is spent as either heat or mechanical stress, and where only about 30-40% of the energy goes into what it is supposed to be doing properly, the rest of the energy goes somewhere else in the unit or system, leading to breakage or failure.
“When a pump runs efficiently, you have a system running the right way with everything balanced, so almost by default, you’ll have a more reliable system. Reliability in many ways is more important than efficiency. Usually when you achieve efficiency, you achieve reliability,” Michael said.
Refurbishments
Correct selection of pumps for the application is important. One way that pumps are damaged, through faulty choice, is via a process called cavitation.
When the inlet pressure of a water pump falls below pump design specifications, tiny vapour bubbles can form in the water around the eye of the impeller.
When the water containing these bubbles is forced into a high-pressure environment on the other side of the impeller, these bubbles collapse, thereby creating tiny shock waves and points of high temperature.
These shock waves corrode the surface of the impeller. To prevent cavitation, the water pump must always be operated within its pressure and flow specifications.
“When we see pumps that are damaged onsite, quite often we prefer to repair them because for one, it takes less time than supplying a new pump; and two, the repaired pump is actually stronger and better than the existing pump,” Michael said.
“We can improve the mechanical seals, we can diagnose problems, so we can come back to them with something which is much more reliable, which is probably half the cost of a new pump.
“We’re really interested in that type of work and really it comes down to fault-finding and discussing problems.”
Fire Protection Pumps
“Kelair provides a whole range of fire pumps for mine sites,” Michael said.
“The environment at sites is tougher and harsher than within the confines of a plant room in an office building, and the pumps tend to be used a lot more as they are integral to other systems.
“Some of these fire pumps are placed into containers, including sea containers, which require a high level of engineering to do based on what has to be built; its robustness and durability; and the delivery over long distance to, say, the Pilbara, which requires a fairly high-spec unit.”
Containerised fire pump units are purpose-built by the Kelair Pumps Building and Fire Division to suit individual requirements.
Offering a compact, pre-fabricated and complete packaged solution, these containerised pump sets are simple to mobilise and transport.
Fully-tested to AS2941/ISO9906 and pre-commissioned, the fire pump sets are fully-piped with valved suction and discharge manifolds, while the wall insulation keeps operational noise to a minimum.
Turnkey installation saves time and labour costs, whether it be diesel or electric pump sets for fire hydrant, sprinkler, combined hydrant/sprinkler, deluge, foam, water mist and hose reel applications.
The fire hose reel and jacking pump sets are electrically-driven with a flow range 0.5l/s to 50l/s, with larger units provided on request. These units boost water pressure to fire hose reels or the system main ring as and when required and perform the task of maintaining the system pressure against minor leaks.
Kelair Pumps’ fire pump sets are fully-compliant with each mine site’s requirements and are used across the country by major mining companies such as Rio Tinto, BHP, Fortescue Metals and Glencore.
Power Stations
Many larger mine sites now have their own power stations, for which Kelair can provide chemical injection and chemical dosing packages.
Power stations that are run by diesel fuel sometimes have their own boilers, for which the boiler feed water requires treatment. These chemical dosing packages feed the right amount of chemical into the water.
About Kelair Pumps
Kelair Pumps specialises in industrial pumps and pump packages for the mining, oil and gas, chemical, pharmaceutical, food and beverage, paints, inks, adhesives, power, water, wastewater and industry in general.
It also specialises in high-rise applications, cold water boosters, variable-speed pressure systems, hot water circulators, fire protection hydrants, sprinklers and combined systems.
Stand-alone all-in-one sewage treatment systems for biological reduction of biological oxygen demand, suspended solids (SS) and ammonia are also supplied, along with other packaged sewage and stormwater pumping stations, grease arrestors and coalescing plate separators.
Kelair Pumps is a member of the AxFlow Group, the fluids handling solutions business group within Axel Johnson International.
Starting operations in 1975, the company now has branches in Sydney, Launceston, Melbourne, Brisbane, Mackay and Perth.
It also runs a specialised test facility with the latest technology, giving faster and more accurate results to recognised standards.
The test rig is compliant with Australian Standards AS/ISO 9906:2018/ and an invaluable diagnostic tool for pump servicing. Repair crew are also on call 24/7 Australia-wide with fully-equipped mobile service vehicles.
SOURCE
Kelair Pumps Australia
P 1300 789 466
E [email protected]
W www.kelairpumps.com.au
