Zest WEG

The African mining sector presents a unique set of challenges for mining companies looking to explore for or develop an orebody. Owing to the remoteness of some of these sites, they are often isolated from grid power connection.

Electrical equipment group Zest WEG understands that stable energy supply is a critical requirement for the success of any mining venture and manufactures customised mobile generators and substations, as well as modular pre-manufactured substations and electric house (E-house) solutions capable of fulfilling this energy need while also helping to overcome the logistical constraints that many African mining projects face. CHANTELLE KOTZE writes.

Not only do these modular and mobile solutions offer an alternative to traditional fixed-type solutions, says Zest WEG Integrated Solutions executive Alastair Gerrard, they also provide clients with the added benefit of flexibility.

This article first appeared in Mining Review Africa Issue 5, 2020
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Built in accordance to client needs or site-specific requirements, Zest WEG provides power generation solutions, electrical infrastructure solutions as well as mobile solutions (generators and substations), able to meet the specific needs of customers that are still in the process of exploration, site establishment or orebody development.

“It is during this stage of a mine’s development where a mobile solution – which fulfils the energy need for the duration of time that it takes to initially access a permanent grid power connection – makes the most sense,” says Gerrard.

Zest WEG undertook a project for a mining company in the DRC, which had access to some grid power supply to start mining activities but were still planning for additional power to undertake and sustain future development at the mine.

Using a Zest WEG manufactured mobile substation, the company was able to access the energy from the grid and provide the mining company with the necessary power needed to begin construction and mining activities.

“This allowed the mining company the time and flexibility to establish a more permanent substation solution on site without any interruption to its power supply.

“In addition to this, the company could then make further use of the mobile substation when it began developing additional orebodies in close proximity to one another, moving the substation to each orebody to power the necessary construction and mining activities,” explains Gerrard.

Moreover, Zest WEG worked with a gold mining company in South Africa where it developed a mobile diesel-powered generator set solution to enable the mining company to have readily available emergency power supply at several of its mineshafts.

The gold mining company reconsidered its initial plan to establish permanent, fixed, diesel power stations at each of the shafts, and instead chose to use mobile diesel generators because of the relatively close proximity of these shafts to one another.

“Instead of equipping each shaft with a permanent power plant, we produced four 2.5 MW, 6.6 kV trailer-mounted diesel generators, following road ordinance guidelines, that they could deploy to the various shafts, as and when needed.

“The generator units could either be used as single generators, or in different combinations, depending on the load requirement at the respective shaft, as they were all designed for ease of synchronisation with one another and were all connected to infrastructure at the respective shafts, allowing for plug and play within  minutes upon arrival at each shaft.

Gerrard says that this solution allowed for a much more cost effective (capex and opex), flexible solution for the gold miner.

Having supplied mobile solutions for over 10 years, Gerrard maintains that these solutions continue to provide a good opportunity for Zest WEG in the African mining market, where the mitigation of risks associated with on-site work is crucial.

“The development of large projects necessitate having several contractors interacting on site simultaneously, but this often causes project delays,” says Gerrard.

“Our mobile generators and substations alleviate some of these risks as they allow for a lot more manufacture and testing to be done in the factory as opposed to on site – mitigating on-site risk, limiting the amount of contractor involvement, reducing the costs associated with standing time on site and allowing for plug and play upon delivery,” he explains.

Modular, pre-manufactured containerised substations and E-houses provide speedy solution

Zest WEG has seen a growing trend in the deployment of modular, pre-manufactured containerised substation and E-house solutions, owing to their indirect cost savings and ease of on-site establishment, says Zest WEG executive Bevan Richards.

This is a more attractive solution, compared to traditional brick and mortar solutions, specifically for clients in Africa who want to limit risks and establish solutions on site as quickly as possible.

There is, none the less, a similar growing trend within local South African operations for similar reasons.

The deployment of these pre-manufactured and fully-tested electrical substations and E-houses reduce the amount of site-based labour and civil work required, with only very basic foundations required to support these structures, Richards explains.

The pre-manufactured container substation solutions are housed in standard 6 m or 12 m shipping containers, with no limit to the configuration of these, whereas the company’s pre-manufactured E-house solutions – the more custom engineered of the two solutions – are custom designed, engineered and manufactured accordingly in any ‘transport splittable’ configuration and to any size.

Unlike the majority of companies that participate in the containerised and modular E-house sector, which are mechanical companies outsourcing to electrical original-equipment manufacturers (OEMs); Zest WEG is in a unique position in that it is one of very few OEMs that has both the electrical skills base and the mechanical manufacturing capability.

“As an electrical engineering company, Zest WEG does not need to rely on a third party electrical manufacturing company to produce the electrical components or integrate any of the electrical components into the substation or E-house.

“Because clients are able to place a single order with us, which we singlehandedly coordinate and deliver from start to finish, it results in shorter lead times for customers,” Richards explains.

When delivered to site, the pre-manufactured, preassembled and interconnected structure (which has already undergone a factory acceptance test by the client) is offloaded, placed into position (reconnected – in the case of the more complex E-houses) and secured to the civil interface on site.

Richards says that installation and connection on-site will vary from a maximum of 10 days for a very complex pre-manufactured E-House to as little as one day for a simpler pre-manufactured substation. This is a significant reduction in both time and risk compared with brick and mortar building construction on site.

While challenging enough to establish construction operations on site in countries like South Africa, crossing the border into Africa compounds these challenges as well as the associated cost of constructing a brick and mortar substation in remote regions, says Richards.

Zest WEG has delivered in excess of 23 pre-manufactured E-house solutions to the market, in various applications.

This includes a pumping application at an underground gold mining operation in Ghana, a conveyor application at an underground coal mine in South Africa; as well as a combination of an E-house and pre-manufactured containerised solution for a catalytic converter manufacturer in South Africa.

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