Selecting the Best Pumping System to Meet a Mining Site’s Water Management Needs

Mine sites are home to significant water management challenges. Whether a site is dealing with groundwater swells, nearby water sources, rain and snow accumulation, overall mining waste processing – or all of the above – the safety and productivity of a mine come down to reliable and efficient dewatering across a variety of application needs. For mining engineers, that means selecting a pumping system that is built to handle the unique challenges a mine site faces. Choosing the right pumping system isn’t just about addressing immediate dewatering challenges; to assure that water management is effective for the long-term, mining engineers need to evaluate a pumping system across a range of unique factors.

This article takes a closer look at many of the parameters and questions mining engineers should consider when selecting a pumping system – from water quality and volume to site size and well depth. It also explains the different types of systems available and the benefits they offer under different operational conditions and applications. Finally, it provides resources and guidance on using online tools to compare, contrast, and select the best pumping system for specific mining site needs. 

Assess Your Site's Water Management Challenges

Mining sites can be harsh environments that are difficult to access and challenging to maintain. High environmental pressures, safety demands and overall productivity all factor into finding the right pump for a site’s needs and are often unique considerations only mine operators face. When it comes to dewatering, consider these typical mining site demands: 

• Mine topography: Where is the water and where does it need to go? How far underground is the water and where does it need to be moved to? Is the water clean and being diverted to a close natural water source? The more linear and vertical feet of pumping required, the more extensive a dewatering system will need to be since not every pumping system will work as efficiently over longer distances.  
• Water volume/flow: How much water needs to be moved? Are the dewatering needs constant or occasional? Be specific when considering the gallons per minute (gpm) or flow rate requirements of the application since this is a major consideration when evaluating pumping options. 
• Water chemistry: What is the solids content of the water? Is the application moving naturally occurring minerals such as sand and rocks or harsher elements like acid or waste? Solids not only effect the weight and volume of water management needs, but can also affect the equipment itself, since not all pumps are engineered to handle abrasive or corrosive elements.  
• Water quality: Does the water need to be treated? Mining operations in remote and dry locations often need to recycle the water they pump out. Others may be pumping out waste that must be treated to meet Environmental Protection Agency (EPA) regulations 
• Mine size: How much space is available to accommodate the pump? Not all pumps are small – yet many mining sites have limited real estate to house a pumping system. Is the pump located deep underground in a small area? Or just 50 feet below the surface? This consideration works hand-in-hand with another one: the accessibility of the pump for service and priming. Not all pumps are self-priming and service-free. If the mine site team needs to reach the pump to keep it operational, will they be able to?  
• Power options: In some cases, an electric-driven pump package may be the right choice for a mine. The heavy tanker trucks needed to refill a diesel pump package may result in too much wear-and-tear on some mine sites, making electric a smarter choice. However, if a mining site does not have power or the job is temporary, diesel is typically the best choice as it will cost more to run power to the mine site than operating a diesel pump package. 

Finally, consider the overall natural environment and weather conditions. From sandstorms to blizzards, what type of rain, cold, heat and unexpected conditions might the site face?

Compare System Capabilities

A pumping system that is designed to meet the unique demands mining operations face is more likely to keep running through every tough mining challenge. Finding the pump that works best for a site’s needs often comes down to comparing how today’s pumping technologies differs from one another – and how a site’s available power source can factor into selection. Consider these typical pump system options:  

Surface Pumps vs. Submersible & Vertical Lineshaft Turbine (VLST) Pumps 

Surface pumps are designed to be used at ground level. Their rugged design and easy access make them ideal for wastewater disposal, reuse, slurries and tailings, as well as general dewatering. Self-priming versions will continue to reprime automatically after initial priming, for less maintenance. The best surface pumps for mining applications will feature impellers designed with materials such as stainless alloys and high-chrome white iron that maximize resistance against abrasives.

Submersible and VLST pumps are available in custom configurations to meet a variety of demanding application requirements. Submersible and VLST pumps are available in custom configurations to meet a variety of demanding application requirements. Submersible turbines are typically paired with fully encapsulated or rewindable submersible motors and VLST pumps are paired with a surface motor, however both can be used for most general dewatering needs. They can also be used to access nearby water sources. Submersible pumps are often ideal for smaller mine sites where there is limited real estate to house a surface pump, since these compact pumps are out-of-the-way and protected within the mine shaft. A combined approach can also be taken, operating a submersible pump deep within the area being dewatered alongside a surface pump to move the water completely out of the mine.   

Diesel- vs. Electric-Driven Pump Packages

 

If electricity is available at the mine site, mining engineers will want to consider using either a diesel- or electric-driven skid and trailer package. If the mining application requires varying duty points, an electric-driven package can offer unique flexibility, allowing the pump to meet the specific efficiency and performance requirements of each application. Portable electric driven pump packages are typically paired with variable frequency drives (VFDs) so that multiple performance conditions can be achieved with one pump simply by adjusting the speed. This flexibility makes electric-driven packages a great choice for maximizing return on investment, since one pump can do the job of many. Electrical packages also offer environmental benefits, since they run clean – minimizing harmful emission and mitigating hazardous waste cleanup from leaks and other EPA regulations.  

While electric-driven packages have some cost and performance advantages in certain types of applications, there are still circumstances when diesel-driven packages are the better choice. For example, consider the operating environment. To use an electric-driven pump package, the mine site will need to have access to on-site power. Ideally this power should run across the entire mine so the pump can be used in multiple applications (fixed or portable). Having access to power in all locations across a mine site that have a pumping need may not be practical or cost effective. In these instances, the profitability and simplicity of a diesel-driven package will provide more flexibility. If site power is unavailable, a generator will be needed. This can add to the pump package’s initial cost. In this case, a diesel-driven pump package may be a lower upfront investment. 

Configure a Pump for Optimal Results

When it comes to comparing and configuring the best pump for a mine site and its application needs, online tools can provide guidance and allow selections to be made across multiple product categories for a single application.

Here’s one example of how the online tool FE Select assists with product selection, using the performance requirements of a general dewatering application. FE Select, from Franklin Electric, is secure and free-to-use. Users input parameters, and the tool does the rest: fully specifying what products are recommended, including the necessary components, a list price quote for the system, and links to related informational product documentation. Since both surface and submersible pumps would be viable product choices for this application, FE Select allows users to search for both types of products, starting with submersible and VLST application needs.

These inputs generate several results, sorted by hydraulic efficiency. The list can easily be narrowed down based on the parameters that are most important to the user: desired speed of operation, number of stages, bowl diameter, power rating and more. Most users typically look for a product that falls between 80 and 85% efficiency:

FE Select then correctly matches the components necessary for the desired application, provides a list price quote for the package, and offers links to related informational product documentation as well as pump and motor performance curves. 

These steps can be repeated for surface pumping equipment, considering variables such as Net Suction Positive Head Required (NPSHr) that are unique to this type of pump. NPSHr is evaluated based on the Net Positive Suction Head available (NPSHa) of an application — or the absolute pressure on a liquid at the suction port of the pump. NPSHa is a calculated value for every application, whereas NPSHr is a calculated value for the pump and is typically provided by the manufacturer. Online product selection tools often have NPSHr values calculated to help ensure users choose a product that does not cavitate, and that meets the application and performance requirements.

For example, if a pump needs to dewater a mine pool, a greater NPSHr will create a pumping situation where more water is left in the pool.

 

Other factors to consider include speed, horsepower and pump size, which can be easily assessed by viewing a pump's performance curve. When reviewing the performance curve available for the pump, look at two to three different performance points within a single pump to account for the pump handling the changing water levels. FE Select walks through the process from start to finish. Users can do either a basic search that requires only primary application data, such as flow and total dynamic head demands; or a more advanced selection that considers some additional variables unique to the situation.

Does the application need a product that is temporary or permanent? How far is the closest water source and where does the pump need to be placed? For example, a VLST is going to be easier to install in a 340-foot-long mine that’s underground whereas a mine that’s 50-feet long with above ground access will utilize a surface pump more effectively.

As these examples demonstrate, online tools can be invaluable when it comes to selecting the best pumping system to meet a mine site’s needs. Just as critical is outlining a site’s unique needs and using these variables to narrow down the hundreds of different pump configurations available into the one that will maximize investment and deliver reliable water management. With 24/7 online and mobile-friendly availability, online tools help to walk users through the process from start to finish, instantly formalizing deliverables with printable and downloadable quotes – giving mine owners and operators what they need to keep operations running smoothly.

As featured in Pit & Quarry’s article, Selecting the Right Pumping System

Author: Luke Tucker, Marketing Strategist, Franklin Electric Company Inc., 310 S Sequoia Parkway, Canby, OR 97013, Phone: 503.956.4266, www.fewater.com, ltucker@fele.com