New Linatex sand plant for Scorton Quarry

Working on behalf of principal contractors Whitwick Engineering, Linatex have recently installed a new sand-processing system at Tarmac Northern’s Scorton Quarry, near Richmond, North Yorkshire. Replacing an old and obsolete plant that had provided a single grade of sand, the requirement from Tarmac was to improve the quantity of fines and produce two materials (fine building sand and medium concrete sand). Initial site analysis using borehole tests verified that the material was clean and coarse, with an average sand content of 40%.

Up to 180 tonnes/h of –5mm sand (including crushings) are discharged from two screens and fed to the new sand plant. The process requires the incoming feed to be flumed to the centre of a 1,676mm diameter S-Type classifier that uses 1,500gal of water a minute. This unit splits the incoming flow, with the fine sand tending to pass upwards and coarse sand downwards.

The coarse sand is drawn from the base of the classifier by a 200/150 Linapump 111R and pumped, via 200mm diameter pipework, to a 914mm HK200 sand separator for washing and dewatering. The dewatered product has a consistent moisture content of approximately 20%, irrespective of the feed density.

The coarse-sand separator is mounted in a tower and provides a 3,750-tonne capacity stockpile via a swivel box and three Linatex-lined discharge chutes, which form a clover-leaf stockpile arrangement (ie feed one, dry one, sell one).

The overflow from the HK200 is returned to the vicinity of the classifier by 250mm diameter pipework, with a branch to the classifier providing and controlling the up-current in the vessel, while the remainder flows to an existing effluent tank.

Fine-sand treatment, although very similar to the coarse-sand process, required smaller-sized equipment without classification. The fine-sand overflow from the classifier is flumed to a 2,440mm diameter feed-regulating sump and then pumped, via a 150/125 Linapump 111R, to an HK125 sand separator, thereby providing a 1,100-tonne stockpile capacity, again via a swivel box and three sets of discharge chutes. Any overflow is directed back to the effluent tank.

All the feed and return pipework is mounted on trestles that also support a walkway for pipe maintenance and access to the towers, which in turn are equipped with maintenance platforms to appropriate health and safety standards.

All design work, drawings, delivery, erection on prepared foundations and commissioning was completed by Linatex engineers.