Aggregates are basic raw materials for the construction industry without which houses, schools, hospitals, factories, offices and roads could not be built or maintained.

Aggregates can be split into two main groups:

> Primary aggregates such as crushed rock and sand and gravel which are extracted directly from the ground at quarries (land-won aggregates) or dredged from the sea (marine dredged aggregates).

> Alternative aggregates such as "secondary aggregates" (by-products of mining or quarrying operations and/or industrial processes such as slate waste or old blast furnace slag banks) and "recycled aggregates" (derived from processing of construction, demolition and excavation wastes such as crushed concrete, bricks and glass; road planning and railway ballast)

It can be easy to underestimate the importance of aggregates to the economy and to our quality of life, because they tend to be high volume relatively low cost materials. They are at the start of the supply chain for the construction industry and their true value lies in their eventual end-use.

The Managed Aggregates Supply System

A national Managed Aggregates Supply System (MASS) has been in place since the 1970's. To date this system has successfully maintained sustainable supplies of these essential construction materials. The system operates through a number of regional Aggregate Working Parties which apportioned the regional figure of need for aggregates to the mineral planning authorities. Cumbria is a member of the North-West Aggregate Working Party.

The North West, as a whole, meets only around half of its aggregates consumption from within the region. Cumbria helps to meet the needs of other parts of the region, but much of the shortfall is met from other regions, for example, quarries in Derbyshire and north Wales supplying Greater Manchester.

Cumbria and Lake District National Park Joint Annual Local Aggregates Assessment

The National Planning Policy Framework requires mineral planning authorities to plan for a steady and adequate supply of aggregates by preparing annual Local Aggregates Assessments. The County Council has produced a Local Aggregates Assessment for Cumbria jointly with the Lake District National Park. The document sets out information about the sales and reserves of quarries within the county. It also takes into account the high specification road stone quarries in the Yorkshire Dales National Park.