Rugged planetary gearboxes from Brevini are helping to reinvigorate the coal mining industry of Wales

Established in 2004, Cowbridge-based Metal Innovations is at the forefront of this resurgence in interest. The company is devoted to the design and production of a new generation of highly efficient coal mining equipment that it hopes will make many of the region’s coal seams economic once more. To prove its claim, the company owns and operates its own mining operation at the Blackbarn mine near Pontypool.

While there is certainly coal under the hills of South Wales – experts estimate that 70% of the region’s reserves are still in place – much of the remaining material is distributed in relatively small, low seams. Large, conventional mining machinery simply won’t fit into these seams, while manual mining methods are too arduous and expensive to consider. The answer, according to Metal Innovations managing director Gareth Thomas, is a new type of mining machine, one that is smaller, more manoeuvrable and more efficient to operate than anything seen before.

Metal Innovations first product was the Celtic Miner 4500. This compact, tracked mining machine has a powerful hydraulic cutter and material removal arm that can access coal in seams up to 4.5m in height. The machine itself is extremely compact however, allowing it to squeeze into the smallest commercially viable coal seams. An integrated conveyor system within the machine allows material to be cut, collected and removed by a single operator, dramatically improving productivity compared to conventional mining approaches.

Designing a machine with the capabilities of the Celtic Miner was a significant challenge. The coal mining environment is an extremely tough one. Machinery is exposed to high peak loads, water, dust, slurry and freezing conditions, while the difficult economics of modern mining mean that downtime must be kept to an absolute minimum. Safety is also critical in the underground environment and all equipment must meet demanding legislative requirements to eliminate the risk of flame or sparks.

To further complicate matters, the compact design of the Celtic Miner means there is little space inside the machine to house its mechanical components. To overcome these difficulties, Metal Innovations turned to planetary gearbox specialist Brevini UK. The Celtic Miner 4500 uses two compact close-coupled planetary gearboxes and hydraulic motor units in its bespoke track drive system and another gearbox and motor to power its rotating cutting head.

“The Brevini planetary gearboxes are the ideal solution for the Celtic Miner,” explains Brevini UK sales director Jon Snaith. “Planetary gearboxes are particularly compact and, as they transmit power through multiple gears instead of just one, they are particularly resistant to high peak loads.” The Brevini products selected by Metal Innovations have been specially developed for tough industrial environments and feature robust mechanical seals to keep water, grit and debris out. They are also constructed without the use of aluminium to meet ATEX fire and explosion proofing criteria.

“The mining application is a great test of our products,” continues Snaith. “The taper roller bearings gearbox in the cutting head, for example, must withstand all the axial and radial forces generated as the head plunges into the coal seam.” To further increase fire safety in the mine environment, all the hydraulic equipment on the machine is filled with Hydrotherm 68 LW Red, a 80% oil, 20% water-based hydraulic fluid, which places special demands on seals and connectors.

Brevini has provided parts and technical support to Metal Innovations throughout the development of the Celtic Miner. Brevini supplied gearboxes for the first prototype machine in 2006 and, based on its positive experience during the design, development and testing process, Metal Innovations has specified Brevini products for the production versions. The company plans to build 20 machines this year at its new assembly facility in South Wales.

Today, Celtic Miner 4500 machines are in commercial operation at Metal Innovations Blackbarn mine. The aim, with a staff of twenty, is to produce 1000 tonnes of coal per week. “Using the Celtic miner, our people can produce more in 2.5 hours than a conventional team of ten would produce in an eight hour shift,” says Metal Innovations’ Gareth Thomas. The Brevini gearboxes in the machines have operated reliably since starting work at the mine.

Metal Innovations is continuing with the development of a further range of equipment including a super-compact mining machine – the Celtic Miner 1500 – that will be suitable for seams only 0.8 m high. Other products now being tested include a mobile conveyor system, a tracked dumper truck and a robust hydraulic power pack suitable for underground use. The company is also exploring other potential uses for its equipment, in tunnelling and rescue operations for example.

“Our equipment is the key to a totally new kind of mining industry,” says Thomas. “We hope it will play a role in revitalising the economy of Wales and the UK coal industry as a whole. To achieve this, however, we must be able to operate with the utmost safety and reliability. Our partnership with Brevini is helping us to achieve just that.”