Why SANDPIPER’s AODD pumps are ideal for mining conditions.

A Whitepaper by Paul Vermaak, Warren Rupp® Inc. Market Mining Manager

When mining underground, the number one danger to all miners is water. Water at the mine face has always been a particular challenge, as this section is the newest area of the mine with many potential unknowns behind it. Water comes from seepage through rock cracks, hidden cavities, and the drill rigs themselves, always presenting a danger to the miners.

Limited pool storage for water at the mine face combined with risks to health and safety and equipment makes the challenge to extract water from this environment an important one. This whitepaper describes the benefits of SANDPIPER’s air-operated double-diaphragm (AODD) pumps over other pumps, including…

• Increased portability in challenging mining conditions
• No need for electricians or other specialists for operation
• A drastically decreased risk of overheating from running dry

Keep reading to learn more about how SANDPIPER’s AODD pumps can make mines safer and more efficient. 

Other Pump Technologies

Traditionally, miners use a pump to draw the water away to a larger pool where more pumps are used to draw the wastewater to upper levels (depending on the depth of the mine) and eventually above ground. 

A common pumping technology used at the mine face is electric submersible pumps (ESPs). These pumps are centrifugal pumps, which means that they use a rotating impeller to draw fluid in and push it out of the outlet of the pump. However, ESPs cause several pumping challenges at the mine face.

Running Dry:

Since the water pumped out of the mine is usually seepage, there is a constant collection of it. Using electric submersible pumps (ESPs) will work, but there is always a minimum depth before the pumps start to run dry. 

For ESPs, running dry will cause the lower mechanical seal to heat up due to the speed of the turning impeller from the electric motor. A sudden impact of freshwater could cause the mechanical seal to rapidly reduce in temperature, possibly leading to premature failure where water would then be exposed to the rotor-stator. This would render the submersible pump useless and would require maintenance such as seal replacements, motor rewind, or at the very least, a “bake and varnish” of the stator.

Finding the Best Pump for Mine Face Dewatering

A solution to overcome this issue would involve using float switches to switch the ESP on and off. However, in practice with large equipment, these float switches are often damaged prematurely, and the cycle of maintenance continues. This still presents other issues associated with this pump technology underground. 

Portability:

ESPs have a multitude of issues when it comes to portability:

• ESPs require an electrician on-site to install or remove the electrical cable.
• ESPs with heavy motors require special lifting equipment to move the pump.
• ESPs are limited to their electric cable.
• With water always around, ESP electric cables damaged by heavy equipment present a health and safety risk to employees. 

pH Levels:

Depending on where the mine is geographically located, there are various pH levels of the seepage water. This could harm the casting material that the electric submersible is made from. The bigger cast iron submersible pumps would probably endure such exposure, but at the mine’s face, the amount of water needed to be pumped requires smaller pumping units, usually with different materials depending on the brand. 

Limited Flow Rate Range:

As stated before, an ESP is based on a centrifugal principle, meaning that at a certain speed of rotation the pump will produce a flow rate against a specific total manometric head. To meet the ever-changing water demand, the pump’s flow rate is either fixed to the pump’s rpm limitation and a fixed total head, or expensive additional equipment like an AC inverter is used to regulate the speed proportionally to the flow rate. Remember, the size of the impeller within the volute of the pump also restricts these parameters.

Other Centrifugal Pump Issues:

Other centrifugal pumps used at the mine face are similar to electric submersible pumps. The primary difference is that instead of submerging the pump in water, you use a suction hose to allow water into the impeller and discharge out the volute. Besides priming obstacles, the technology and inherent pumping issues at the mine face are the same as the submersible principle’s shortfalls. You will, however, need to make use of a strainer and foot valve to ensure the volute is full in order for the centrifugal to prime. It’s important to note that centrifugal/submersible pumps do not suck liquid, as they require liquid within the volute to draw new liquid in and are subject to NPSHr. 

Benefits of AODD at the Mine Face

Warren Rupp’s SANDPIPER brand of AODD (air-operated double-diaphragm) pumps offers many solutions to dewatering the mine face. Let’s explore this technology. First, to best describe the solutions SANDPIPER pumps present, let’s dive deeper into the benefits this pump technology brings to the table. 

No Problem Running Dry:

Let’s begin by understanding the pumping principle of an AODD pump.

The main pumping action of the diaphragms inside the pump is a back-and-forth motion within contained liquid chambers, with the use of either flap valves or ball valves in the top and bottom manifolds.

This motion generates little heat and therefore can run dry for extended periods of time without damage to the pump, making it ideal for the mop-up operations of pumping water away from the mine face. 

Increased Portability:

With its compact size, no rotating parts, and no need to rely on an electric motor, the SANDPIPER® AODD pumps are very portable, with no need for electricians or electric cables like ESPs. In fact, our specialty mining pumps are designed with lightweight materials to make them even more portable. 

Finding the Best Pump for Mine Face Dewatering

pH Levels:

AODD Pumps are offered in a wide range of different materials in both body and internals. AODD Pumps from SANDPIPER are offered in either metallic or non-metallic options, both of which are suitable for all water types no matter what the pH Levels.  

Flow Rate:

With no need for expensive control equipment, Warren Rupp’s SANDPIPER AODD pump’s flow rate can be controlled with the adjustment of air pressure, making this pump technology ideal for variable speed requirements in ever-changing mining conditions. 

Versatility: 

Warren Rupp’s SANDPIPER® AODD pumps are so versatile that they can be hung on a mine wall, preventing unforeseen external damage from other mining equipment. They can even be submerged in small pits/pools of water, making it a very versatile pump for the mine face. 

No matter the pH or type of water at a mine’s face, Warren Rupp’s AODD Pump Range has a solution for your needs. With heavy-duty flap valves and heavy-duty and standard ball valve technology available, we have the right pump designs to handle your most difficult dewatering applications with a focus on product reliability and safety. 

Lightweight and portable, with no need for electricians or heavy equipment specialists, SANDPIPER AODD pumps are the ideal mining face pump.

For more information or the request a quote, contact SPRINGER PUMPS® today.