Five aspects to consider when selecting dewatering pumps for quarrying

The first consideration is where the water is being pumped from and where it is going. Apart from overcoming gravity, all pump sizing must consider the amount of friction that needs to be overcome along the entire discharge line length. The so-called head of the pump is the combination of gravity and friction that must be considered for a particular application.

The sum of gravity and friction, or total head, and the inflow to be dealt with, determine the pump size. We need to apply these concepts to all pump selections, not just in quarries. What can make quarry selection unique is that the distance between the pump and the surface level of the water being pumped might vary over time. A pump that was working efficiently and effectively six months ago might not provide the same performance when the quarry has become considerably deeper due to the greater vertical elevation difference that needs to be overcome.

When the water comes in and needs to be removed, operators will tend to use whatever is available, possibly using the wrong pump for the required flow and pump head. In addition, if the water rises more quickly than is being pumped out, there could be a tendency to use more pumps. Usually, there is no time to change to a bigger pump, so they use what is at hand. Of course, when there is a planned extension to the quarry, they are more likely to select the correct pump from the beginning.

There is a wide variety of pumps available that can extract water out of a quarry. Dewatering pumps are designed specifically for removing dirty water and are built with more wear-resistant parts. An ordinary pump, for instance, even if chosen according to the correct flow and pump head requirements, would, after time, pump less and less water out of the quarry. By choosing pumps that resist wear better, quarry operators can reduce their environmental impact while increasing uptime.

Solids suspended in water can cause an impeller to wear and prematurely fail. Atlas Copco’s PAS - PAC range of surface pumps, for instance, which can handle liquids containing solids of up to 100mm in size, has several design features to ensure it performs reliably for more extended periods. The closed impeller in the PAC H pumps is equipped with deflector vanes that keep the mechanical seal clean and free of detritus, making it last three times longer. Additionally, it eliminates the need to flush the pump with water to keep it clean, saving significant energy and money throughout the pump's operational lifetime.

In addition, Atlas Copco’s PAS - PAC self-priming pumps incorporate many design features to provide reliable, high-performance pumping so operators can improve their efficiency and productivity. For example, mechanical shaft seals are set in an oil bath, enabling dry running without damage.

For electric submersible pumps, Atlas Copco has introduced a new patented Wear Deflector Technology platform for the WEDA D line, an innovative hydraulic design that provides a high pump efficacy. The impellers in this pump are made from high-chrome stainless steel and, as such, have high hardness and exceptional wear resistance. The Wear Deflector Technology is already finding its way into other WEDA submersible pumps as they receive design updates.

Whether there are excavation or blasting operations within the quarry, dewatering pumps need to be moved, which means they have to be transportable. However, when moving pumps around, there is also rough physical handling to consider.

Transportability is essential, especially for heavier surface pumps. The PAS pump range, for example, is available with a galvanized undercarriage or skid, which is resistant to corrosion and makes the unit easy to move around on site. This range of mobile dewatering pumps recently added the HardHat® canopy, a robust polymer, as an alternative. And the models featuring this technology have a road towing trailer for superior transportability.

For WEDA submersible pumps, the power-to-weight ratio is far superior to conventional pumps. They weigh up to 40 percent less, which makes them easier to handle and move around a site too. They also feature general robust design decisions in combination with specific solutions, such as shock absorbers, so they are more resistant to rough handling.

Routine preventative maintenance may also be delayed when other pressing matters present themselves in the daily course of business. This is one of the biggest differentiators of the dewatering pumps from Atlas Copco, which have been designed with ease of maintenance in mind.

Referring back to the PAC H pump, its semi-cartridge seal design allows changeout without dismantling the pump, reducing downtime and simplifying maintenance.

Thanks to a novel Atlas Copco hinged door design on the pump itself, the PAS – PAC pumps provide superior serviceability on site. All components are exceptionally easy to access for simple servicing and maintenance. The pumps can be cleaned and restarted in a matter of minutes and serviced in under 60 minutes, making them less of a barrier to routine maintenance.

The latest WEDA drainage pump additions feature a cartridge-type sealing system with a stainless steel body that enables maintenance to be carried out on-site, ensuring that operators achieve minimal downtime. They also feature easily accessible oil inspection plugs, reducing the time needed for routine inspections and maintenance.

In Europe, and especially in certain countries where the rental market for dewatering pumps is around 75%, local aftersales support is essential. All pumps in the Atlas Copco range come with full aftersales support and ready availability of spare parts via the company’s global network of customer centres. Product training is also available, particularly useful for rental companies with their own maintenance crew. 

Taking advantage of digitalisation, QR codes are also being implemented, meaning that essential information about parts and spares is just a scan away. Rental firms can also take advantage of the Fleet Link telemetry solution by Atlas Copco, a secured and remote monitoring feature. Hence, operators are always in control of pumping equipment and operations.