Widely recognized for their ability to accurately classify specialist sands, CDE have now turned their expertise to lignite removal. Concrete producers tend to shun sand with visible lignite as it rises to the surface of concrete mixes — a particular problem for flooring applications. This has had a major impact on the market value of lignite-affected sand in regions where lignite is common. The largest lignite seam in western Europe extends under Lough Neagh (itself the largest body of fresh water in the British Isles), close to CDE’s head office in Co. Tyrone. The lough is dredged for sand by a number of companies and lignite is a constant problem. CDE have addressed this with research and prototype development projects for local customers, giving the company a unique insight into lignite-removal systems.
The north-east of England is another region commonly affected by lignite problems, and early boreholes for F.D. Birds’ new sand and gravel project at Catwick Quarry in Beverley, near Hull, showed that lignite would be present in all extracted sand and gravel. Managing director John Bird entered discussions early with CDE to achieve a complete lignite-removal solution, ultimately resulting in the company’s 170 tonnes/h installation.
The dumptruck feed hopper (40-tonne capacity) is fed via an access ramp. Its heavy-duty design and 6in tipping grid accepts ‘as-dug’ material while removing excess oversize. Feed is then conveyed to a twin-deck R2M108 (20ft x 6ft) rinsing screen. This separates oversize, intermediate aggregate and sand. The oversize is stockpiled while the –5mm slurry passes to a CDE Multi- Sands plant.