Walsh has been chosen by Imerys Minerals to process by products from its massive china clay operations.

The Imerys china clay plant in Cornwall generates millions of tonnes of material annually which can be processed into secondary aggregates – also known as “stent”.

Westley Pickup, Commercial Director of S Walsh, said: “It has always been our long term vision to secure a sustainable resource to build a Greener London.

“We have undertaken extensive research and know that these products can be used more widely for infrastructure, residential, commercial, education and health construction projects.

“Secondary aggregate from china clay waste meets the requirements of sustainable building in the UK.

“There is a huge lack of understanding of availability and potential for this ‘secondary’ resource and we expect that through our commercial relationships we can share what the possibilities are.”

Imerys has also signed a deal with local Cornish firms Brookland Sand and Aggregates and Denis May & Sons.

An Imerys spokesman said: “We are pleased to have made these appointments after a significant and thorough review of the marketplace.

“We were very keen to ensure that we made every effort to secure partners who best understood our strategic aims and could help us make the most of the aggregate by-products which come from our China Clay production process.

“We look forward to working with all of our partners to deliver this objective”.

Products sourced from Walsh can be used to produce construction products such as asphalt, ready-mix concrete and various concrete products such as blocks, kerbs, flags, bricks and precast products constituting up to 100% secondary aggregates.