"We've got the hills, you've got the holes." is how Imerys - the former English China Clays - is marketing the idea.

Selling china clay waste for use in construction is an old idea which has taken on a new life.

It is costly to transport the waste any distance but this sideline of the clay industry could now become much bigger business as a new government tax penalises construction firms that use conventional aggregates which have to be specially dug out of quarries.

Aggregate products

As part of its renewed sales drive, Imerys is now planning to build a �17m docks facility.

Clive Kessell of the St Austell-based company, said this aggregates levy made their familiar by-product look more attractive.

"It was brought to light because of the new tax imposed by Gordon Brown in last year's budget of �1.60 on all aggregate products mined out of the ground," he said.