Page 16 - Hub-4 Magazine Issue 76
P. 16

 Low-carbon secondary aggregates shipped into London by sea
The first sea shipment of construction aggregate derived from Cornish china clay waste has been brought into London by UK recycled materials specialists GRS.
The delivery marks the start of an exclusive deal which enables GRS to import more than half a million tonnes of secondary granite – branded Enviroc® – from Cornwall into London each year by ship, with a fraction of the embodied carbon of other construction aggregates.
London developers looking to build greener can specify the GRS material, available in bulk or bags, for almost every construction application from sub-base and capping layers to structural concrete and asphalt, and even decorative landscaping.
Recognised by leading green building rating systems as one of the most sustainable alternatives to newly quarried aggregates, Cornish granite has previously been used in a handful of London developments, including the Olympic Park. But its widespread use has been constrained by the belief that transporting it into London is not viable.
Yet in partnership with the Port of Tilbury, GRS has invested £4 million in a new Molson CDE aggregates processing plant on the dockside to produce a range of high-quality, certified single-sized products to meet the needs of construction across London. Because of the plant’s location, that material can be delivered across the capital by road, rail and even river using GRS’s wholly owned Thames freight business Walsh Marine.
Power for the aggregates plant is supported by an on-side wind-turbine and the stone washing system uses rainwater that is recycled and reused time after time. Silt washed off the stone is collected for use in land remediation schemes further down the Thames and GRS says these ‘fines’ may themselves be used to produce a lightweight aggregate in the future.
For centuries, the production of china clay (kaolin) has shaped the Cornish countryside. For every tonne of china clay extracted, around 9 tonnes of granite by-product are generated – this has built up into enormous waste piles estimated to be around 500 million tonnes which are now the
source for Enviroc aggregates. The new venture sees GRS’s Cornish subsidiary Maen Karne haul the raw material from a china clay pit near St Austell to nearby Fowey harbour where it is loaded onto ships to make the 400 nautical mile trip to Tilbury for processing.
 | p16 | Sept/October 22 - Issue 76

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