The outcome from the audit was that the overall system was extremely inefficient, due to the fact that over a period of many years, the standards and protocols for maintenance and repair of pumps of this nature had been abandoned.

The water reticulation system was also complex due to the multiple pump stations required on various levels, to cater for the enormous volume of natural fissure water present which is typical in this region. The mine was at great depths as well, with the bottom-of-mine pump station just below 900 m from surface. 

The Primary objective

Apply best practice technology and methodology such that the system will reliably deliver targeted volumes, in the most energy and cost-efficient manner. 

The Solution

Scamont took control of the complete underground system, from the penstock valves upstream of the settlers all the way through to the discharge outlets on surface. This included the following corrective actions: 

• Cleaned and serviced all the settlers.
• Upgraded settlers where possible to increase the capacity per unit.
• Installed flocculant dosing plants before the settlers.
• Complete mud underflow management from the settlers, using our range of Positive Displacement pumps (See below image)
• Re-introduction of repair standards that complied with best practice including the following: 
  • Hydrodynamic Pump Testing as per ISO 9906:2012 1B
  • Rotating element dynamically balanced to ISO 21940-11
  • Pressure Test pump as per SANS 347:2019
  • Standardization on all multistage pumps to our GHP Range (See below image), as well as optimized the pump sequencing on each level 

The End-result

The corrective actions described above yielded not only a stable pump system but efficiency gains that resulted in a significant reduction of maximum power draw in order to meet the daily flow requirements. Increased standby capacity was also achieved because these flow requirements were being met with less duty pumps than before.

The theme forced us to change our perspective from always being engaged in the present, to looking towards the future!

The opening keynote speaker was Beau Lotto, the founder and CEO of the “Lab of misfits”. His keynote topic was – “Thriving because of uncertainty”. A very interesting and relevant topic in our industry. He challenged us to think differently and used the analogy of a surfer, encouraging the industry to “ride the waves” instead of standing still and trying to fight them. He also challenged us to make the implicit – explicit.

Many fruitful discussions were had, from engaging with mining colleagues at the social functions, listening to the thought-provoking plenaries and informative technical sessions. As these discussions converged it started to paint a picture of how we are going to mine for future generations.

Some of the key discussions included:

• Autonomous mining vehicles and how they can boost production in the mining sector.
• Conversion from diesel to electric mining vehicles.
• Environmental and Social Governance (ESG)
• How drones and vehicles can collaborate more in the mining environment.  

Many of the technical programs were centred around how the world needs the mining industry to provide the essential minerals required for electric vehicles. As can be seen below, there is an expanse of minerals required to manufacture an electric vehicle:

It was apparent that in order to keep up with the demand of the minerals required, mines will need to transition their operations from open pit to underground, to extend the life of mine (LOM). Many of the technical discussions were also centred around Original Equipment Manufacturers (OEM’s) ensuring that their equipment was aligned with this transition.

In conclusion, it was a very worthwhile visit for Scamont Engineering, and we look forward to playing a more active role in the Canadian mining market.

Remember – if we can’t grow it – we need to mine it!

The most common systems in use in the industry are:

The above systems have a multitude of limitations and downsides, with the main ones being:

• Intermediate dams between levels silting up with solids
• An extensive number of pumps required to keep up with the water demands
• Limited to Low-to-Medium volume applications
• Lack of redundancy, whereby the loss of 1 pump (breakdown) in a Cascade System or a Series System will shut the entire system down and if no redundancy exists, no pumping can take place until the breakdown unit is brought back on line.
• Intensive maintenance requirements
• Power Intensive

Scamont Engineering advocates that the pump supplier must engage with the mine or mining consultant during the early stages of mine development, in order to ensure that the dewatering system can be designed in phases, for the duration of Life of Mine (LOM). The main advantage of our technology is that there is no need to utilise the above mentioned systems. Instead, we have created our own unique system with the following positive attributes:

• High Head
• High Volume
• High Efficiencies

Scamont Engineering is currently engaged with many clients around the world, assisting them with the most appropriate dewatering solution for their specific requirements.

Through our projects that we are currently executing it has become apparent that our GSB Multistage self-balancing pump is the technology of choice for High-Volume / High Head dirty water applications.

We are also however executing projects that require Low Volume / High Head dewatering. In this instance we offer our range of positive displacement pumps.

Most of the mines mentioned in Figure 1 utilize a conventional underground dewatering system. In these conventional systems all the dirty water from the mining operations, as well as the fissure water, transfers down to the shaft bottom where the underground settlers (sometimes referred to as clarifiers) are situated.

Before the dirty water reaches the settlers, it is pre-conditioned in two ways:

• The grit (typically consisting of particle sizes ranging upwards of 500 µm) is removed to ensure that it does not cause blockages downstream.
• Hydrated lime is dosed to correct the pH, to ensure the water remains pH neutral, thus preventing corrosion.

Once the water is preconditioned in this manner it is ready to be clarified in the settler. In the settler solids are separated from the water by means of gravity. The process is assisted by dosing various flocculants and coagulants, which agglomerates the finer particles so that they are able settle out easier.

The overflow from the settler, known as “clear water,” reports to the clear water dam/s, and the underflow from the settler, known as “mud,” reports to the agitated mud dam/s. 

The clear water can now be re-used underground for mine service water (MSW) or pumped to surface to be used in the process plant. If there is excess water, it is typically discharged into the environment if it meets the environmental discharge limits. Some mines treat the excess water to potable standards, which can then be used in the hostels, offices and for chemical make-up in the processing plant.

Due to the depth that some of these underground mines need to go to reach the reef, the dewatering pumps are required to operate at high pressures, while ensuring the power input is kept to within the mine’s requirements. It is therefore imperative that the pumps selected for the system can operate at a high efficiency, and more importantly can maintain that efficiency over the lifespan of the pump.  

For this reason, the pumps, and services we offer our customers include:

Multistage clear water pumps:

GHP

Balance disc assembly

SRB

Balance disc assembly

GSB

Self-Balancing

Positive displacement mud pumps:

FXG

Duplex double-acting reciprocating piston pump

SP 200

Triplex single-acting reciprocating plunger pump

SP 600

Triplex single-acting reciprocating piston pump

Services:

Technical Support

Spares & Repairs

References:

Mining Review Africa (2018), https://www.miningreview.com/top-stories/deepest-mines-world-south-africa-canada/

The Copperbelt refers to an area in Africa that consists of a number of copper deposits and associated mining operations. The belt extends about 450 km northwest from Luanshya, Zambia into the Katanga region of the Democratic Republic of the Congo. The Copperbelt contains more than a tenth of the world’s copper deposits! 

The mines in the Copperbelt are notoriously wet. One can easily find operations in the Copperbelt that require up to 100 ML/day of water to be dewatered in order for mining to commence. Dewatering up to a vertical head of on average 600 m is also typically required in the Copperbelt. It is for this reason, that the Scamont range of pumps are becoming the preferred choice when high volume and high head dewatering is required. 

Most of these operations prefer to pump dirty water to surface, as only a small portion of the water to be dewatered would be required for underground operations. Once on surface, suspended solids are removed in order to comply with environmental standards by using either clarifiers or settling ponds. The treated water is then typically discharged into the surface water catchment. 

The most significant cost involved in the dewatering of a wet mine is the power consumption of the dewatering pumps. Power input increases as the internal components of the pump wears, which in turn increases the life cycle cost (LCC) of the pump. Therefore, the main focus of dewatering projects must always be a holistic one, taking into account the LCC of the pump station as well as the capital expenditure (CAPEX) cost. 

For this reason, the key technology we offer for these types of dewatering projects is our range of GSB multistage pumps, which offer the following benefits:

• Capable of handling dirty water due to the unique opposed impeller construction. 
• Due to the self-balancing effect of the opposed impellers, costly and maintenance intensive balance disc arrangements (as found in conventional multistage pumps) are not required.
• Only a single pump is required for high heads, instead of multiple single stage pumps in series as is the convention. 
• Various materials of construction are available, depending on the water quality. 

As Scamont Engineering we always stress to our customers that the success of any engineered system requires it operate within the design specifications after commissioning, and for that reason, we offer support and spares to our customers in the DRC and Zambia. 

References

Heyden, C. & New, Mark. (2003), The role of a dambo in the hydrology of a catchment and the river network downstream. Hydrology and Earth System Sciences. 7. 10.5194/hess-7-339-2003.

Britannica, The Editors of Encyclopaedia. “Copperbelt”. Encyclopedia Britannica, 6 Jan. 2014, https://www.britannica.com/place/Copperbelt-region-Africa. Accessed 9 February 2022.