Leaton’s Big Break

Breedon Aggregates maximize crusher productivity at Leaton Quarry through state-of-the-art Sandvik technology

Breedon Aggregates Ltd are now largest independent aggregates company in the UK, with 26 quarries, 18 asphalt plants and 40 concrete plants in England and Scotland, employing around 830 people. With approximately 200 million tonnes of mineral reserves and resources in the UK, the company is playing an increasingly key role in the supply of aggregates to the UK construction industry and, therefore, places great emphasis on crushing technology and is keen to embrace the latest developments.

One of company’s strategically most important quarries is at Leaton, near Wellington, in Shropshire, where it fulfils a key role as the only quarry supplying hard rock (olivine dolerite) products to the Breedon Aggregates group in England. The rock is particularly popular because it is hard without being too abrasive and can be shaped to suit a wide variety of asphalt applications.

Production of the material at the quarry is maximized by the use of two Sandvik UH440i track-mounted mobile cone crushers. These form part of two mobile crushing trains that supplement production from the site’s static plant. Both UH440i machines are fed with –150mm primary crushed ‘all in’ material, with one machine set up to produce sub-base and the other operating with a pair of mobile screens to produce dust, 6mm, 10mm, 14mm and 20mm single-size products.

Weighing 43 tonnes, the UH440i is built around the proven and highly durable Sandvik CH440 cone crusher, which delivers the optimum combination of throughput and product shape. The crusher itself is controlled by Sandvik’s patented Automatic Setting Regulation (ASRi) control system, which ensures a smooth flow of material and high productivity levels. The entire crushing process is continuously and automatically monitored by this intelligent system, providing the operator with valuable operational information.

The ease of operation of the Sandvik crushers has been a key element in the success of the machines. However, it is their ability to easily produce a range of material grades that has made them an essential part of the production process at Leaton. Breedon say the machines are producing four different products to a very high quality at a rate of approximately 270 tonnes/h.

Moreover, the UH440i’s ability to cope with the often onerous nature of the production requirements means that, during periods of peak demand, they have on occasions worked from 5am until 11pm. Whereas with previous crushers at Leaton, this would have generated a significant amount of wear, due to the quality materials used in the Sandvik crushers, operators at Leaton report that the new machines have shown no significant signs of this occurring.

Although the performance of the two Sandvik cone crushers has been excellent, Stuart Hopley, quarry manager at Leaton, was quick to take advantage of the latest development from Sandvik that aims to optimize the crushing process – the oversize breaker mantle (OBM). The Sandvik-developed and patented OBM optimizes the crushing process, producing a finer product and achieving greater reduction through the crusher. As a result, Leaton has experienced a maximum net increase in production with a minimum circulating load, achieving a more efficient crushing operation.

The OBM is able to achieve this due to the latest developments in chamber design. The OBM accepts oversized material in part of the chamber while simultaneously reducing the chamber profile in the opposing part of the chamber, which permits operation at a tighter setting. This not only results in a finer product being produced on a ‘first pass’ basis, but also a superior shape, which is essential when the equipment is set up to produce single-size products. In addition, when the OBM is operated in conjunction with the on-board ASRi control system, greater control can be achieved when producing sub-base material.

This has undoubtedly been the case at Leaton Quarry, where both UH440i cone crushers have been fitted with the new technology. ‘The Sandvik cone crushers have become integral to our production here at Leaton, but we are always keen to take advantage of the latest developments in order to boost our production,’ said Mr Hopley. ‘The difference the mantle makes is essentially improved crushing efficiency. In simple terms, that means we get better productivity and lower cost per tonne. Also, as Breedon is a company that is keen to minimize its carbon footprint, improved crushing efficiency not only means better production, but also lower emissions.’