Sandvik Crushing and Screening Plant Installed at Moons Hill Quarry

23 September, 2014

First published in the September 2014 issue of Quarry Management as Second Wind

Major investment in new secondary-stage processing plant sees John Wainwright & Co. boost production capacity at Moons Hill Quarry

Last year was marked by a great deal of activity for Somerset-based John Wainwright & Co. Ltd. In particular, the company’s Moons Hill Quarry saw £3.5 million invested in a secondary-stage aggregate processing plant, to replace equipment which had been in use since 1963. The new 20m high plant is estimated to be 60% more productive than the previous facility and utilizes some of the most modern and efficient crushing and screening equipment manufactured by Sandvik Construction.

John Wainwright & Co. have been supplying premium aggregates to the construction industry since 1891 from their two Somerset quarries, Moons Hill and Stoke. The company is proud of its independent status and renowned for its innovation, environmental and ecological awareness, as well as its strong local roots, which are reflected by the part the company plays in fulfilling its community responsibilities.

‘Our independence and shared values set us apart in our sector,’ said managing director Peter Barkwill, who explained Wainwright’s business ethos: ‘The company has maintained its market share through the expansion of its core capabilities, major inward investment, the professionalism of its extremely experienced staff, and, ultimately, the quality of its major asset – the basalt upon which the company was founded.’

For more than 100 years Wainwright have been extracting basalt from their Moons Hill Quarry. With a minimum PSV of 57, the material is the only source of surface course quality aggregate within Somerset and the surrounding region. Once extracted by drilling and blasting, the basalt passes through an extensive crushing and screening process to produce both single-sized and blended aggregates. As well as being used extensively for surface dressing throughout the south of England, the processed material has many other applications, including the production of asphalts and concretes, Clause 803 (SHW) Type 1 sub-base, a specialist dust for horse arenas, as well as a non-calcareous aggregate for watercourses.

In the autumn of 2012 foundations were laid for a new scalping plant, which was eventually completed in the summer of 2013. This new plant consists of a scalping screen fed by extended conveyors from the quarry’s existing primary crushing station. New scalping conveyors and a radial conveyor allow two sizes of scalpings to be stocked and blended. Dependant on material quality and weather conditions, the scalping screen and conveyor arrangement allows the scalpings to be recovered and fed into the secondary-stage surge bin.

Recovered oversize scalpings and –200mm crushed rock from the primary crusher are discharged into the secondary-stage surge bin prior to crushing by the quarry’s new Sandvik CS440 Superior secondary crusher, which reduces the feed material size to –63mm. The crushed product is then passed over a Sandvik SS1223 selector screen to remove the –6mm, while the –63mm +6mm is discharged into a hopper feeding two Sandvik tertiary crushers, to produce a –20mm cubical product with a low flake index, which is specifically required for road surface-dressing purposes.

The tertiary crushing station consists of a new Sandvik CH440 Hydrocone crusher and an existing Sandvik H3800 Hydrocone that was refurbished by Sandvik and then relocated from the old processing plant. The tertiary crushed material is conveyed to the main screen house where it passes over three linear-motion screens, each equipped with polyurethane decks, to produce: dust; 5mm, 6mm, 10mm, 14mm and 20mm aggregates; and rejects.

Wainwright opted for Sandvik’s Superior and Hydrocone crushers due to their design features and ability to offer high reduction and excellent product shape. All the crushers offer hydraulic close-side setting adjustment and feature ASRi automation. Additionally, a choice of several different crushing chambers and many other high-performance features make each model more versatile, user-friendly and productive.

The CS440 Superior secondary cone crusher has proved to be an ideal solution to Wainwright’s secondary-stage requirements due to its compact and easy-to-service design. Moreover, the CS440 carries out the same duty as two aging cone crushers it replaced in the original plant. Equipped with Sandvik’s ASRi automatic setting system, the CS440 is playing a key part in maximizing production through the secondary stage of the company’s quarrying operation.

Sandvik’s ASRi system is also fitted to both tertiary crushers and helps to optimize the efficiency and operation of the Hydrocones by automatically adapting the crushers to variations in feed conditions. By continuously measuring and compensating for crusher liner wear, the ASRi system allows Wainwright to fully utilize the crusher liners and schedule liner replacements to coincide with planned maintenance. The ASRi system also assists in keeping the crusher choke fed, thus maximizing rock-on-rock crushing, which helps to optimize the quality of the final product.

Peter Barkwill explained the benefits that have resulted from the new plant: ‘In order to comply with local planning, the new plant has minimal visual impact, while the low noise and low emissions from all the Sandvik equipment is vitally important given the proximity of the plant to both a main road and a village. Community relations are very important to us, and hence these benefits cannot be overestimated. Now fully operational, we estimate the plant to be 60% more productive than the previous installation, with the Sandvik equipment being the culmination of a £3.5 million investment.’