Operations can pump the slurry to an unused area of the mine, but then face the problems of running out of space or wanting to re-enter the dump site. Some operations pump the slurry onto conveyor belts, where it can cause spillage at transfer points and drifts. It can also prompt the washery manager to complain about the amount of water on the belt upsetting the washery. Another option is to pump the slurry to a sump, which then creates the inconvenience of cleaning the sump and disposing of left-over solids.
So what is the answer? Slurry pump specialist Supavac says it has come up with a solution that avoids all the usual problems of slurry disposal and can also make a few extra dollars for the operation.
Supavac's Slurry Management System tank dewaters all types of slurry in what the company says is an "efficient, reliable and simple manner".
Water and solids are delivered to the Supavac SMS tank by vacuum solids pumps, double diaphragm pumps or whatever pumps are in action at the mine. Several pumps can be fed into the Supavac SMS tank at one time.
The slurry mixture passes through the tank where the solids are separated from the water and delivered to the solids discharge end of the tank. The solids are delivered at a controlled rate, making it ideal for loading onto a conveyor belt. Water minus the solids is delivered to the water discharge end of the tank and piped into the normal waste water system.
Supavac has found in most cases the mine slowly delivers solids from the tank back onto a conveyor belt and this is conveyed out of the mine with run-of-mine production.
"The solids going on to the belt usually contain a high percentage of coal. In these cases the Supavac SMS tank pays for itself with saleable product returned to the belt, which would normally be lost forever," the company said.
The tank operates fully enclosed and with low energy, and is only slightly larger than the average underground pump tank. It also has only one moving part.
Supavac has developed various SMS tank models including those suiting varying throughputs of water and solids.
The pumps are sold directly. Supavac products are also available for hire through Coates, who will be on show at AIMEX.