Tema Machinery supply new Delta II screen to Moons Hill Quarry

1st September 2014

As part of a major plant upgrade Tema Machinery have recently supplied a Hein Lehmann Delta II intensive action screen to Moons Hill Quarry near Radstock, Somerset. Hein Lehmann are one of the sister companies of Tema (Machinery) Ltd.

Owned and operated by John Wainwright and Co Ltd the company have been supplying premium aggregates to the construction industry since 1891. Now as then, Wainwright's are proud to be an independent business, renowned for its innovation, environmental and ecological awareness and strong local roots and community responsibilities. This independence and those shared values set them apart in their sector.

Wainwright's have maintained their market share through the expansion of the company's core capabilities, major inward investment and the professionalism of its extremely experienced staff at all levels and ultimately the quality of its major asset, the basalt upon which the company was founded. This basalt extrusion is the only example of hard stone in the Mendips and was formed in the Silurian period, approximately 425 million years ago.

New investment

Last year saw Wainwright’s most significant investment in recent years, spending £3.5 million on new quarry processing plant. This has taken the form of a secondary-stage aggregate production plant, replacing equipment, some of which had been in use since 1963. This involved bringing up to current standards the secondary and tertiary processing sections linking them all up with appropriate conveyors to the existing primary and final screening section.

Foundation works began in the Autumn of 2012, with the project completed and commissioned in October 2013. The twenty metre high new plant, constructed by Devon based Centristic is up to 60% more productive than the old facility.


Delta II Screen

As part of this investment Tema Machinery supplied a new high efficiency Delta II screen which was supplied with WS85 polyurethane screening media.

Prior to winning the order, Tema Machinery held numerous site visits to discuss the machine and its capabilities and how it would cope with the ‘difficult’ material to be processed.
The material is a capricious ‘basalt’ material with a variable amount of volcanic and clay fines within the product which can be as high as 30%. When the material is in a damp and poor condition it needs to be screened at a 40mm setting, however when the material is clean and fine there is a desire to be able to screen at 20mm so that there is an optimisation of reclaiming the high value stone for aggregate use and consequently reducing the waste scalpings element from the stone.

Peter Restorick – Project Engineer, commented, “We looked carefully at a number of options which included the concept of the Tema machine as a high resonance and high action screen that would satisfy our needs. After supplying Tema Machinery engineers with test material, (with positive results) two of our key personnel were invited to visit a similar application in Belgium and were very satisfied with the performance of the equipment.”

“It was obvious from the outset that the uniqueness of the computer controlled synchronisation of the two screen drives eradicates some of the traditional wear associated with trying to link two separate drive units together. As this is normally done by mechanical means of either teeth or belt or similar system the Delta II proved to us it was certainly innovative and offered us the best chance of recovering good material from the scalped element of the product.”

With the mechanisms positioned over the spring mounts the Delta II screen provides very quick synchronisation by electronically timing them away from the mechanical timing, thus equating to a very smooth electronic and mechanical operation with no excess vibration in the structures.
Kevin Sargant – QM, commented, “Given the difficulty of the product and a brand new plant the screen has functioned perfectly. We did have to make some changes to the feed size and the amount we put over the screen but after the feed changes the scalped product off the screen we have had is very good.”

“There was also a preference to go with the WS85 media system as it was already in use in the quarry on the final screening section and had proved very cost effective over the years. The beauty of the polyurethane modules is that if you only get wear in one section they are simple and easy to change, rather than the complete deck. There is also the noise consideration as they are much quieter than the traditional woven wire, with the manual handling aspect being more in line with safe lifting limits. We also found that as the weather changed, the material changed it was easier to make changes to suit and with the new system this became much quicker than previously.

Peter Restorick, further commented, “The screen was installed by the project contractor Centristic in a near seamless operation. We found that the machine was of excellent build quality and after installation, initial operation was very straightforward. The German engineers were also very responsive if we needed assistance at any time and although we had some initial teething problems with setting up the software, these were quickly and easily resolved.”
“It was essential that we maximised the efficiency and output of the new plant. The main criteria behind the purchase and selection of the Delta II screen was that we recognised there was an element of the product going in the scalpings that we could recover and put through the cone crushers, subsequently maximising the amount of reserve we were utilising. The Delta II has provided us with the means to achieve this.”

TEMA (Machinery) Ltd has a number of high quality sister organisations within the group, such as Hein Lehmann GmbH, Siebtechnik GmbH, Steinhaus GmbH, Isenmann Siebe GmbH, Multotec PTY (RSA) and Tema Isenmann Ltd.