Secondary aggregates can be defined as aggregates produced as a by-product of other mining or quarrying activities such as china clay waste (the source of Maen Karne's Secondary Aggregates).
Processing includes crushing and screening, as with primary aggregates, but also the removal of metal, plastic or wood waste. In some locations top soil is produced as a by-product of this processing.
Importantly the green credentials offered by Secondary Aggregates make them attractive to architects and developers. Subject to the Aggregates Levy since April 2014, these materials have now reverted to exempt status. This decision finally represents the end of a dispute that has lasted 13 years, and whilst we may now see the aggregates levy on primary aggregates start to creep up the tax will not apply to 'Secondaries'.