Water Transfer and Dewatering in Mining: Using Solar Energy to Power Operations

PROJECT: INFILTRATION PONDS SYSTEM SUPPLY

Location: Pilbara, Western Australia

BACKGROUND

In any mining application, open pit or underground, dewatering and water transfer play important roles. The successful management of water is key to operations. Often mine sites require water from an alternative source or reservoir to enable water resources for mining processes. Whereas, other sites may need to remove unwanted water to drop the water table so that mining activities can continue. With different water management needs, it’s important to consider all options. Making the wrong choice can cause increased costs and downtime.

Challenges of mine dewatering and water transfer

There are many challenges related to mine dewatering and water transfer in mining. These may be specific to the location or other conditions and might include:

• Remote locations: The location of a mine that is isolated won’t have an existing powering pumping system. Maintenance is a concern as well. Using bore pumps for an entire system that’s spread across many kilometres is an issue with varying control of pumps that should be running, those that shouldn’t, and others that have failed.
• Variable flow rates: In a continuous pumping situation, variability can become part of the control challenge when there is a need to transfer large volumes or when additional head is required.
• Water conditions and quality: If the water is high in saline, it will have an affect on the products required.
• Declining water table
• Site requirements related to Occupational Health & Safety (OH&S) and environmental requirements
• High costs, which are impacted by all other challenges; water management in mining is expensive but not optional

Harnessing solar power

Australia has been a proponent of solar energy for years and its use continues to grow. As of July 2017, Australia had over 6,216 megawatts (MW) of installed photovoltaic (PV) solar power. The sun after all is the largest source of renewable energy. Sunlight is present in many regional mine sites throughout the country. Thus, it makes sense to use the sun as a power resource.

When other means of power aren’t available, it makes even more sense to turn to solar power. Allied Pumps was able to use solar power to help a client with telemetry repeater systems, which allowed communication points at remote locations on-site without the need for generators or running expensive power lines.

An iron ore mine operating in the Pilbara region, Western Australia required the supply of a transfer system to pump water into a mine site infiltration pond system. Infiltration ponds or basins are one type of water management system used in mining. They are similar to a dam or turkey nest, but the pond consists of a plastic cover and liner with holes. These holes feed a controlled amount of water back to the water table. These infiltration ponds have historically been effective as a “fast response” tool to increase water levels and lower salinity.

IDENTIFYING THE CHALLENGES

High efficiency pumps needed to run 24/7, yet diesel consumption by engines needed to be low. Thus, an alternative energy source was needed. Diesel engines consume a large amount in 24 hours and would need to be topped up regularly. The diesel driven water transfer pumps were positioned on the edge of the dam but were inaccessible for regular fill ups. The fuel tank was too large to fit on-site next to the water transfer skids.

Communication was also required with the location of the water transfer without the use of running power or generators. These were stringent site specifications so innovative solutions needed to be considered.

DETERMINING THE BEST SOLUTION

Working with a hydraulic consultant, Allied Pumps found the best fitted pump for the site. Allied Pumps supplied three diesel driven water transfer systems as well as a diesel fuel system and four solar powered telemetry repeater stations.

The diesel fuel delivery system designed by Allied included a 5kL fuel tank, which fit along the dam’s edge to feed water transfer pumps. Approximately 100 metres away, Allied placed a 62kL bulk fuel tank to feed the pumps and small fuel tank.

Each of the solar powered telemetry stations consists of a battery box on the bottom, a controller with flow and level instruments and a solar panel on the top to charge the batteries and run the controller. The controller radios back to the main system and back out to site.

During the manufacturing process of this solution, the client was able to be a part of every phase, inspecting the equipment and attending testing. The client had full visibility into the electrical and mechanical design and manufacturing.

IMPLEMENTING THE SOLUTION

Each pond at the site has its own flow meter and level transmitter. They work out the total water quantity filtrated then report back to the site SCADA system. One skid operates at the diesel pumps with its own flow meter and level transmitter in the main dam. This controls all pumps.

The system was tested at an AS2417 certified facility. The system was then installed and fully commissioned on site, incorporating original pump selection and motors.

This was a successful project for both the client and Allied Pumps. As a provider of dewatering and water transfer pump solutions, we are committed to finding the best results for our clients, no matter the challenge.

To discuss your next dewatering and water transfer pump solutions project, please contact us.