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New Powerscreen Washing Plant for Grundon's Butts Lake Quarry

Mineral extraction has been an important activity of the Grundon Group of companies since the company was founded in 1929; currently operating from their head office at Ewelme near Wallingford, Oxfordshire the company operate nine quarries across Southern England, one of which is in East Anglia.

Grundon's core business is the supply of sands and aggregates to the building and construction industries but they also have an 'open door' policy which actively encourages the public, small builders, landscapers and DIY trade to visit and purchase directly from our quarry weighbridge offices. The care and high standards which characterises Grundon operations are maintained throughout their wide range by the services of independent consultants and testing laboratories which ensure the best possible product quality control.

Butts Lake Quarry at Padworth is where the company process their Golden Shingle, this is the most popular of their products, it is a very decorative shingle which some major bagging companies bag to supply through outlets like DIY superstores, garden centres, stone merchants and builders merchants nationwide. The shingle is a naturally occurring, uncrushed, washed and screened Thames Valley Flint, which is very hard and does not lose its colour.

Production at Butts Lake Quarry was previously handled by an old conventional static plant, Grundon’s needing to increase production; process more difficult raw material and also eliminate loss of fines to lagoons decided to install a new Powerscreen Washing Systems full aggregate wash plant. Their decision to choose a Powerscreen wash plant was based on the company’s success with similar contracts throughout the industry.

Plant Operation.

Designed to operate in excess of 130 tph the plant utilises the Fines Master 120; with its combination of bucket wheel and twin hydro cyclone sand recovery system this machine ensures that fine sand losses to the ponds will be minimised thus maximising production.

Sand and gravel is imported from another company owned site and loaded into a 20 tonne feed hopper with remote control tipping grid, this material is then fed up a 65’ 00” inclined lattice conveyor.
All material is then delivered onto a 12 x 5 static rinsing screen which features a rolling chute arrangement and all-round galvanized walkway for ease of access. This screen separates the oversize, with the underflow passing through the bottom deck and then to the Fines Master 120.
This efficient machine comprises a twin bucket wheel, a centrifugal slurry pump, twin hydro cyclones, a collection tank and a high frequency 12 x 5 ft dewatering screen mounted on a single chassis to produce the grade of sand. The -5 product is then delivered via a T5032 powered radial conveyor onto a stockpile.
The remaining oversize material passing through the rinser is fed into a Powerscreen Powerscrub 120 log-washer.

To maximise sand production any adhered sand from the scrubbing process is fed via a pump back to the Powerscreen Fines Master 120.
Capable of producing up to 120 tonnes/h of contaminant-free sand and gravel, the Powerscrub 120 unit comprises an inclined trough fitted with two counter-rotating axles with Hardox 500 exchangeable blades and an elevated spray-bar system. The unit mixes incoming feed while milling and washing the material at the same time,
mid-size material passing directly through the Powerscrub is then fed onto a 65’ 0” transfer conveyor. Material from this conveyor is then fed into 12 x 5 part-rinser; fitted with spray bars this machine features a rolling chute arrangement and all-round galvanised walkway for ease of access. The material is then given a final wash before it is screened to three separate T5032 50’ 0” stockpile conveyors providing stockpiles of 8/10/20/40 mm.

The new Powerscreen Washing plant has provided Grundon’s with huge improvements on overall production and product quality enabling the company to increase their market share.