Wales Environment Trust

Aggregates are the basic constituents used in construction and can be generalised as:

• Primary Aggregates: Naturally occurring bulk materials such as rock, sand and gravel, which are extracted directly from land or marine sources for use in construction;
• Mineral Waste: Material arising as a by-product of mineral extraction that is capable of use, either with or without further treatment, as a primary aggregate substitute, for example crushed rock fines and slate waste; and,
• Secondary/Recycled Aggregates: Previously used materials that are capable of being substituted for primary aggregates. These include material from construction, demolition and excavated waste, and the by-products of industrial processes, such as steel slag or pulverised fuel ash from power stations.

Primary aggregates production in Wales has declined from a peak of 26 million tonnes in 1989, to just under 20 million tonnes in 2001.

Primary aggregates production in Wales is dominated by crushed rock including limestone, sandstone and igneous rocks. In addition to these, land based and marine dredged sand and gravels are produced.

There are large quantities of mineral waste in Wales, e.g. crushed rock fines, slate waste and colliery spoil, all of can be used, or have the potential for use in aggregate markets.

Recycled aggregates: In 2003 arisings from Construction, Demolition and Excavation Waste were in the order of 6.24 million tonnes. Of these 30% were recycled for aggregates use, with a further 24% re-used at licensed landfill sites, mostly for restoration and site engineering works.

Secondary aggregates are a by-product of industrial processes including steel production and power stations. In general all of these materials are used, with large quantities being supplied into the aggregates market.

Email: info@walesenvtrust.org.uk