Mine water applications require specialised pumping technology. Katrina Zlobich, business development manager, Grundfos, talks to Water&Sanitation Africa about Grundfos’ holistic offering to the mining industry.

What are the challenges South Africa faces when it comes to addressing mine water?

KZ  Mine processes create acid mine drainage – the acidic water that is created when sulfide minerals are exposed to air and water through a natural chemical reaction. Mine water effluent needs to be treated for reuse within the plant or safe discharge to the environment to avoid contaminating other natural resources.

The cost of energy means that water treatment technologies and associated products, particularly pumps, should be as energy-efficient as possible. For a long-term solution, sustainability is vital to any system and, as such, the selection of processes and products plays a big role in overall sustainability.

Which processes and stages of mining does Grundfos offer pumping solutions for?

Grundfos is a world leader in the supply of pumping solutions for mine water utilities, from raw water intake to water treatment, recycling and disposal. We offer mining companies a long-term partnership, which includes the expertise to meet their needs in every requirement for a reliable pump solution, be it for surface, open-pit or underground mining. Grundfos pumps are built to last, even under the toughest working conditions.

Apart from initial transport and slurry pumps, Grundfos can supply to all processes and stages at the mine, even if water contains abrasives such as sand or is in a low pH environment, for aggressive media, such as leachate solutions, or liquids used for cleaning and maintenance.

A partnership with Grundfos will offer an individual approach to each customer and a solution to any application. We offer great reliability and robust solutions, which ensure a high level of security for operations.

What products and solutions does Grundfos offer for mine applications?

Grundfos offers a variety of products for mine applications, such as:

Mine water utility and water treatment: There are several different methods for mine water treatment, including precipitation, reverse osmosis and ion exchange. Grundfos can supply pump solutions from submersible to end-suction pumps as well as our state-of-the-art vertical multistage centrifugal range (CR). This year, we are launching a larger Grizzly CR pump range, which offers a maximum flow up to 225 m³/h and up to 40 bar pressure.

Mine water treatment includes a variety of chemical dosing. Our complete range of dosing solutions can cover small to large applications in basic or advanced functionality, depending on customers’ needs. To insure compliance with water-quality requirements, we offer the Grundfos DID online water analyser, which can be fitted with a variety of sensors, able to measure up to three different water parameters on single controller.

Open-pit drainage/dewatering: Grundfos dewatering pumps are designed to work in the toughest environments and can be found in mining applications and offshore industries worldwide. We can supply dewatering pumps for durable use and heavy flows that can be installed dry or submerged, available in higher-grade material and anti-corrosion versions for severe conditions. Surface-mounted axle-driven pumps are also available if the depth requirements are limited.

The solid cast iron construction and narrow design characteristics of the Grundfos DWK dewatering pumps range make this pump ideal for pits, temporary or permanent installations and offer high-pressure pump performance unhindered by sand, small stones or other abrasives.

In cases where more mobility is required, Grundfos offers its DW range of pumps, which are lightweight, providing extra mobility.

Peripheral dewatering: Peripheral dewatering and the maintenance of a constant water level typically involve a number of wells installed around open-pit mines. Grundfos can offer a flexible and effective solution for removing clean or dirty water with particles and adjusting water levels with boreholes from 30 m to 600 m. Higher-grade material and anti-corrosion versions for pumps and motors are also available for severe conditions with low or high pH and chlorides.

For example, Grundfos can supply SP pumps with an empty chamber that offers a fast and effective solution when greater depth and power are required by replacing the impeller in the chamber.

In situ leaching: In situ leaching is a process of recovering minerals such as copper and uranium through boreholes drilled into the formation, without the need for conventional mining. Grundfos can supply submersible and end-suction pumps that ensure effective pumping.

Leachate solutions vary according to the ore deposit. This places heavy demands on pump construction, and Grundfos offers customised pumps for in situ leaching. Pumps ranges are available built with high-grade steel or, in some cases, titanium, and with a magnetic drive or various kinds of shaft seal solutions.

With possible great fluctuations in demand for performance and multiple pumps installed, adding variable frequency drives will equalise the hydraulic load to the wells, automatically adjusting pump speed to the required demand with state-of-the-art controls.

How do you ensure your pumps can withstand the corrosive properties of mine water?

Correct material selection is the most important method of corrosion prevention, prolonging the lifespan of pump systems and insuring trouble-free operation. Grundfos can supply the specialist expertise to help meet your performance objectives, from the initial identification of needs to the selection, installation, operation, and maintenance of the pumping solution.

Do you utilise sensors and monitoring technology for early problem detection?

Automation is critical for mining applications. Grundfos’ solutions include early warning notifications and logging systems for plant optimisation, energy savings and safe operation. Although the majority of our products are pumps, Grundfos focuses on developing in-house electronics and controls for optimal pump performance and protection (VSD, motor protection relays, motor controllers).

We also have our GRM (Grundfos Remote Management) program, which allows for full monitoring and control of systems remotely. Our communication modules can be linked to other available Scada or communication systems. We offer a wide range of sensors that can be adapted to these systems to prevent damage but also ensure that systems are maintained and serviced at regular intervals.

How do you ensure low life-cycle costs for your pumps?

Grundfos intelligent control units, if installed, ensure that the system always operates at optimal efficiency and performance, and even has functionality to request services on certain wear and tear items installed in the pumps. This leads to systems increasing their lifespan significantly.

What service agreements do you offer for mining applications?

Our service agreements recognise the greater requirements for maintenance in mining applications. A partnership with Grundfos focuses more on the pumping solution than the pump itself. We remain with our customers for the entire project and plant life cycle, offering pump performance witness testing, commissioning agreements to ensure correct installation, and service level agreements that cover all operational cases, from routine maintenance to spare parts and pump audits.