Secondary aggregates are a by-product of the china clay production process.
Around 6 tonnes of saleable aggregates are generated for every tonne of china clay.
This levy-exempt aggregate ranging from fine sand to gravel and crushed rock is used among other things for block manufacture, roads or as fill material.
For more details see:-
Imerys are actively seeking all and any opportunities to grow the export of secondary aggregates from Fowey Docks.