How to Do Proper Pump Selection for Mine Dewatering

By superadmin on May 13, 2018 in Blog, News

Pump selection for mine dewatering is a huge cost decision (both in upfront and operating costs). In addition, the proper selection of the pump for this purpose may greatly affect the efficiency and safety of many mine operations.

To accomplish this, it’s best to focus on the objective of mine dewatering. Then, we’ll discuss what the role of the pump is in the whole project and how to select the proper one for optimal results and efficiency.

What is mine dewatering

To make mining safe and stable, the conditions should be relatively dry. As a consequence, the water must be removed or managed so the crew can better work in the site. To accomplish this, a pump is often necessary to “move out” the water (or “dewater” the site).

Both levels of groundwater and surface water should be controlled to achieve geotechnical stability. This approach also makes mining methods safer and more efficient. The engineers and crew would then be able to assess and work the site in a shorter time period under safer conditions.

When it comes to managing groundwater levels, the two approaches are exclusion and pumping. Exclusion is about preventing the groundwater to enter the jobsite in the first place. On the other hand, pumping is about actively “transporting” the water into another place to lower the groundwater levels.

To achieve exclusion, cut-off walls are installed around the site. These act as physical barriers to prevent water from coming in. It’s like sealing off the site so there will no intrusion or inflow of the water.

To enable successful pumping of the groundwater, the water is actually pumped from inside the pit. Often the water is also pumped from wells around the pit. This is to control or minimise the flooding of the area. It’s also a controllable and flexible approach to achieve desired groundwater level. In most cases though, it’s ideal to create or maintain a relatively dry condition.

In the case of open pit surface water, one effective method is to divert or intercept the flow of water so it won’t fill the work area. Engineers and crew also create temporary storage areas of the water (through pumping and creation of sumps).

Benefits of mine dewatering

Whichever approach is used to create or maintain a relatively dry working area, the goal is to make the site safe and stable. Without the pit flooding, there will be minimal downtime which results to faster completion of the project.

In addition, the lower water content of the ore and waste rock will result to lower transport or haulage costs. That’s because dry ore weighs less which reduces costs in hauling or transporting it.

This dewatering aspect of the mining operation is actually crucial in its success and progress. In fact, many mining operations in the past have been abandoned due to flooding or poorly managed groundwater levels. It made the site unsafe and unstable. After all, water absorption by the rocks and soils could make the jobsite particularly vulnerable.

Due to the crucial role of mine dewatering, appropriate strategies and pumps should be employed to ensure safety and success. Moreover, the proper selection of pump could result to significant cost savings and operational advantages. After all, mining operations also heavily depend upon time, performance and costs.

Reliable mine dewatering pump for your application

Mine de-watering is often associated with corrosion, abrasion and high pressure. The pump to be selected should be able to withstand these harsh conditions. As a result, special materials and coatings are utilised. Aside from providing durability and ruggedness, special materials and coatings also lead to lower operating costs of the pump.

For example, the rotors could be made from hard chrome plated stainless steel. Aside from its relative inertness to the usual environments of mine dewatering (e.g. high salinity), the rotors could also reasonably withstand constant use.

Even the skid frame should also display some advantages. It could be made from galvanised structural mild steel. The galvanisation provides a protective zinc coating to the steel (which prevents or slows down premature corrosion and rusting). The result is longer-lasting parts and possibly lower maintenance requirements of the pump.

The maximum flow for most applications could reach 14 to 20 litres per second. This is already adequate for many mine de-watering purposes and sites. The rate is high enough to achieve “drying” of the area within reasonable time. Even with this high flow rate range, many quality pumps can still withstand the pressure (and heavy duty performance) because of their robust construction (special materials and coatings).

Compatibility and interchangeability

Aside from performance, reliability and durability, there are other factors such as compatibility and interchangeability to truly achieve lower operating and investment costs.

For example, the pump should have high flange/pipework compatibility so you won’t purchase additional parts. In addition, the parts should be interchangeable so you can easily fit them into other pumps or easily purchase other parts without worries about compatibility.

This allows you to stay lean and better control the costs. This is especially the case in underwater mining environments wherein huge upfront costs are expected to initialise the operation. Compatibility and interchangeability could somehow lower that upfront cost (or make it a safer investment because there will be fewer expenses down the road).

Other important considerations

Energy efficiency, easy servicing, simple maintenance and relatively small base footprint are some of the other important factors in selecting a mine de-watering pump. After all, these factors also affect the operating costs and ease of usage of the pump.

For instance, many sites are actually crowded and cramped (e.g. irregular dimensions of the site, small available working area). A pump with small base footprint is truly valuable in these situations. That’s why many engineers have used a Heli-flo TF084 (base footprint of 4420 x 1400mm). With its small base footprint and excellent max flow (14 litres per second), it has become a valuable tool in many dewatering applications.

Aside from small base footprint, easy servicing and simple maintenance are also important. This is to minimise downtime and maintain the optimum performance of the pump (simple maintenance tasks will be done more frequently). As a result, the rate of dewatering would be continuous and consistent. This will effectively control groundwater and surface water levels to maintain the safety and stability of the work site.

Of course, energy efficiency also plays a huge role in selecting dewatering pumps. Engineers go beyond exploring possibilities. They’re also required to optimise those possibilities by maximising outcomes and minimising the use of resources (particularly time, money and energy). That’s why electric driven and high efficiency pumps will always be in demand for many de-watering applications.

Pump selection for mine dewatering

In summary, it’s still about achieving the desired result while minimising the use of resources. To achieve the desired result, the dewatering pump should be able to pump the water out within a reasonable rate and time period (14 to 20 Ltr/sec is already adequate for most applications). In addition, the pump should be able to withstand harsh conditions (hypersalinity, high corrosion and abrasion). This is to minimise downtime that could be resulting from parts failure and frequent maintenance of the pump.

The pump should also be easily maintained and serviced so work can continue as much as possible. Many dewatering applications are time-sensitive and require tight deadlines. The pump should work reliably even in harsh conditions and continuous use. This ensures proper control of surface water and groundwater levels which allows for timely completion or execution of the project.

Here at Tru-Flo, we have heavy duty electric-driven pumps especially designed for harsh conditions. Whether it’s for industrial or municipal mine de-watering application, our pumps are designed for long running projects.

With continuous pumping capability and robust construction (chrome plated rotors, galvanised steel), our pumps here at Tru-Flo are sure to have lower operating and maintenance costs. There will be minimal downtime and ensure faster project progress (while maintaining safety and stability of the site).

As a family-owned and operated business, we’ve been providing high-performance pumps since the 1990s. Through the years, we’ve expanded our services to cover various sectors (from agriculture up to underground mining). Contact us today if you require high-performance and cost-effective pumps for your project.