Solar power solutions supplied to opencast mines

The ZRW mobile solar-powered floodlighting system was supplied to Namibian iron-ore mine which requires electricity to run 24/7 Tailor-made energy solutions provider ZRW Mechanika’s supply of solar-powered masts last year to chrome mining company Samancor Western Chrome, which operates an opencast mine in Marikana, in the North West, has sparked interest from numerous municipalities in South Africa, Namibia and Botswana, as well as State-owned power utility Eskom.

ZRW notes that these govern- ment entities requested more information this year on the company’s solar power solutions, designed and manufactured in South Africa by ZRW. ZRW’s Samancor contract involved supplying solutions that could be used to light up the informal settlements around its opencast mine in the Mooinooi area of Bapong municipal district.

Samancor approached ZRW in 2014 on behalf of the town of Marikana, in the Bapong muni- cipality, to supply solar-powered masts to the informal settlements, as crime and unrest were on the increase, ZRW CEO Dr Kamalluddien Parker explains.

ZRW notes that it specialises in adapting to client require- ments and can, therefore, tailor its technology to South Africa and other African environments. “The mining sector is often accused of using power that is not necessarily clean, green or renewable because it is not suitable or sustainable, but there are companies such as ZRW that have the expertise to supply sustainable solutions to the mining industry that work and are cost effective,” states Parker. He notes that Samancor also required ZRW’s solar-powered power packs to electrify remote security and access control booths, located at junctions on the routes used by mining trucks transporting mined materials from different sites.

The trucks often have to be driven 20 km to 30 km through farmland and drivers have to sign in at the booths for security purposes. The solar-powered packs provide power at the remote sites to power radio communication devices as well as lighting around the security booths. Samancor required a maintenance-free solution so that running costs could be limited and to ensure that the solar-powered units did not require continuous and skilled maintenance.

The solution required by Samancor also needed to ensure comparable functionality and features to a grid-powered high mast system, but reduce the burden of electricity running costs or the replacement of bulbs on the municipality or community. ZRW designed and commissioned the solar-powered light- emitting-diode (LED) high-mast system to electrify an area of between 100 m2 and 200 m2 and provide high-powered light output for over three days, even in cloudy or rainy conditions. “This is also the ideal solution for safe, sustainable and environmentally clean electricity in rural communities and informal settlements,” says Parker.

The ZRW system is highly innovative in that the use of remote sensing technology allows, the municipality to monitor the high masts from its offices, including battery capacity or system performance monitoring. ZRW was also approached in 2014 by an intermediate equipment distributor to supply a mobile, compact solar power solution to an opencast iron-ore mine, in Namibia. The mine required a solution which would work in remote applications, as its dependence on diesel generators has become a burden in terms of transport- ing the diesel to site.

The mine required electricity to run 24/7, with especially strong light in the evening to enhance safety and identify where mining vehicles and machines were used for mining. ZRW, therefore, designed its mobile solar-powered flood- lighting system, delivered in 2015. It can be trailer-mounted and towed by a bakkie and is easily erected in any location, the company states.

The solar panels are pneumatically operated to open up into a position suitable to charge the storage battery banks at any remote location. During the day, the system can be used to generate power and charge battery banks, which are used to power nine 80 W LEDs in the evening for up to 12 hours. One solar-powered floodlighting unit contains nine floodlights and can provide light for an area of about 50 m × 50 m. The unit – 3 m long, 2 m wide and 1.5 m high – can retract and be packed away into a compact transportable form to comply with road safety regulations for towing behind a standard bakkie. During 2015,

ZRW successfully supplied 15 units to the Namibian iron-ore mine; however, Parker notes, the company faced challenges while working on the installation of these units. The mine has very specific safety regimes and compliance requirements, including structural integrity requirements, which differ from requirements in the electrical engineering and the energy sectors.

The mine’s safety regulations focus on the issues of connecti- vity of equipment, such as point of connectivity, access control, enclosing and waterproofing, Parker states, adding that it was a challenge to adhere to and integrate the mining and electrical compliance requirements with the need to be electrically efficient and lightweight for the system to be easily transported. An additional challenge was balancing the operational requirements of the solar systems with available skills of the operators on site.

The mobile units needed to be easily deployable, rapidly moveable and simply transported. ZRW adopted a design to reduce operator involvement through automated deployment of the solar panels, using simple push-button control.

The light quality and intensity needed to be consistent with comparable diesel generator units and function in adverse cloudy and rainy conditions. Further, the area for erecting solar panels was limited, and the physical dimensions of the units had to adhere to homologation requirements to be roadworthy. Parker adds that dust in the operational environment was a significant consideration, parti- cularly in the Northern Cape and in Namibia, where the dust is red and oily and tacky, and will stick to electronic equipment and fan inlets.

This affects cooling, printed circuit boards and the functioning of any power electronics. He stresses that dust on batteries is also potentially hazardous. As a result, after the pilot phase of the solar-powered floodlighting system, many modifications had to be made to counteract the effects of the dust through filters and of louvres on the trailer had to be redesigned. ZRW Mechanika continues to provide home-grown solutions for the mining sector, including energy efficient lighting solutions, solar-powered main and backup power solutions as well as power to remote areas, including rural electrification.


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