Dewatering

Almost every mine encounters some degree of water problems, and controlling or getting rid of them requires far more skill, and equipment, than most people know or understand. After all, most photos of  pits, tunnels or shafts focus primarily on people and machines working in dark or dusty surroundings but rarely do they show rivulets or ponds and sometimes small lakes that often hamper mining operations.

In fact, controlling water is such a big issue for mine owners and operators, particularly during Care and Maintenance, that most companies include Water Management Specialists as part of their Operations’ Team to help ensure that mine structures, both open-pit and underground, are safe from failures caused by freshet or other sources unearthed during digging or blasting.

“Springing a leak” is no laughing matter and it takes more than the fabled “Little Dutch Boy” who used his finger to plug a hole in a dyke to stop water from flowing, and when it happens in a mine, it takes a great deal more skill and perseverance to stop it and, more importantly, get rid of it!

With so much at stake, miners cannot afford to have profits washed away and that’s why pumps and the technology associated with dewatering have become such an integral part of today’s mines. Water is certainly an essential ingredient to most mining operations, but like everything else there’s a right and wrong place for it, and in the mine is certainly the wrong place.

Flooding and collapses are the obvious extremes when it comes to water-related accidents, but other issues associated with water that demand equal attention involves the environment and the damage that can be caused by water that has come in contact with highly acidic minerals.

Keeping properties as high-and-dry as possible is paramount to successful mining, but getting them to that point also requires a care and understanding of the consequences of pumping and discharging contaminated water back into the environment.

Simply sucking trapped and often stagnant or otherwise “dangerous” water from mines into neighbouring waterways or onto adjacent properties is not acceptable, nor legal, but thanks to new technologies and highly efficient filtration systems, today’s dewatering systems meet environmental standards and moreover, help make the companies that use them responsible operators.

As every mine owner and operator knows, being a socially responsible corporate neighbour is almost mandatory to conducting business in certain areas and, in fact, without demonstrating CSR, many companies are finding it difficult to be accepted in many communities.

Dewatering a mine site, regardless if it involves a trickle coming out of a garden-size hose or a gusher blasting out of huge hoses or pipes, calls for the right equipment to handle the job properly and responsibly, and the units featured on the following pages are what’s new in dewatering technology to help make mining safer. 

Massive unit handles huge volumes

DIEMME’S GHT 2500 dewatering filter is the largest unit of its kind in the world, weighing more than 100 tonnes.

The unit is specifically designed and fabricated for high-speed pressure filtration on mineral concentrates and tailings. Because of its large chamber volume and filtration area, it is ideal for dewatering massive quantities of suspension while reaching very low values of residual moisture. A special geometry of the filtering elements results in a very high cake drying efficiency using compressed air.

The unit shown here is composed with a mixed plate pack of 89 plates for a total filtration area of 821 m². The GHT 2500 is capable to dewater iron ore concentrate with a capacity of up to 200t/hr and reaching a cake residual moisture of 7-9%.

For more information contact: www.diemme-spa.com/filtration

Cost efficient mine pump

The GEHO-APEXS mine dewatering pump is a positive displacement hose diaphragm unit designed for moving fluids at high pressures and in large volumes.

Due to its design, the pump runs at 3 to 5 strokes per minute, resulting in significantly less check valve cycles, less impact on valve closure and a slower speed of operation…

A hose installed inside the tube protects the pump’s internal parts from abrasive fluids resulting in savings in wear and maintenance costs and an improvement in availability and reliability.

For more information contact: www.geho-apexs.com

Answering demands for dewatering solutions

Metso‘s vertical plate pressure filter (VPA) has been developed to meet increasing demands for higher efficiency and automation in industrial and mining dewatering applications.

The new VPA is a heavy-duty machine suitable for metallic minerals, industrial minerals, and coal and tailings. Main features include lightweight construction with machined polypropylene filter chambers, a load cell weighing system integrated to a “smart” PLC-control system for fully automatic filter operation, and a compact design for a reduced space requirement.

Additional design features include a slurry thickener with automatic discharge, a feed slurry buffer tank, flow and density metres for filter feed, slurry feed pump, and a product weighing system for production monitoring.

Metso also offers a full range of other process solutions for dewatering of slurry concentrates and tailings from gravity separation with clarifying and thickening to high-pressure filtration at 100 bar.

Products include Spiral Dewaterers, Inclined Plate Separators, and the VPA plate and frame Pressure Filters and Tube Press.

For more information contact: www.metso.com

Improved in-line pump assembly

FLSmidth‘s new pumps, slurryMAX, millMAX, and gravelMAX, are the biggest in-line assemblies in the company’s complete line of mining pumps.

Each pump features a shaft that is directly connected to a gear reducer which in turn is  connected to an automatically adjusting fluid coupler, then to the motor and all precisely aligned on a common steel base.

The manufacturer commonly uses FALK gear reducers and VOITH fluid couplings.

For more information contact: www.flsmidth.com

Underflow thickener pump

Watson-Marlow‘s SPX underflow thickener pump is a unit designed to handle a variety of harsh materials including abrasive heavy metal slurries and corrosive cyanide, copper sulphate and methylcellulose.

The Bredel SPX handles these materials without damage to the working parts of the pump. The peristaltic hose pumps are virtually maintenance free with no expensive impellers, liners or mechanical seals to replace, no check valves to clog and no rotors and stators to wear out.

In addition, millions of gallons of water can be saved as the hose pump can handle very high solids contents compared to centrifugal type pumps. As an added bonus, this also eliminates the requirement to treat this waste water.

The self-priming pumps accommodate flow rates from 0.1 microfilter to 350 gpm and can withstand pressures up to 232 psi. There are no internal universal joints, valves, dead corners, or glands to impede flow and the pumps are reversible for backflushing lines.

They can also run dry indefinitely with damage and provide up to a 30′ suction lift.

 For more information contact: www.watson-marlow.com

Submersible dredging pumps

Dragflow‘s submersible dredging pumps are units designed for heavy-duty applications, especially for slurry with abrasiv
e solids, and are capable of pumping as much as 70% solids by weight up to 5″ diameter solids.

The portable design of the pumps makes them ideal for mounting on excavators or to be incorporated into a barge system that can then pump water and sediment slurry into a holding/drain off tank or geo-tube for drying and then haulage.

The process helps improve overall productivity partially due to the dry haulage of the sediment material compared to hauling heavy slurry from traditional methods. The pumps are designed with agitators and cutters to allow the equipment to pump large quantities of solids even in the presence of very compact soils.

Dragflow’s dredging pumps can perform high-depth dredging operations up to 100 m and 150 m for deep dredging operations and can pump sand and gravel up to 120 mm diameter.

For more information contact Dragflow at: info@aquatd.com

A “Monster Pump”

Technosub has just completed production of its “Monster Pump,” a product that can handle 1000 gallons per minute at 1700 feet of head pressure.

This massive unit is powered by a 700 Hp motor and features internal components manufactured from duplex stainless steel in order to withstand the hard conditions associated with mine dewatering.

These Technojet high-pressure pumps are designed to be connected to an underground sump where water is fed by submersible pumps and then to the surface tailings.

For more information contact: www.technosub.net