Aggregates provide the backbone of our world. They are an end-product in themselves, but also an essential raw material used in the manufacture of other vital construction products such as ready-mixed concrete, asphalt, lime and mortar.
We are fortunate that aggregates are plentiful in most parts of the UK. This is important as the cost of aggregates can be dramatically affected by the distance it needs to travel.
However, the aggregate resources are not distributed evenly across the country. The 'Stone Line', running roughly from Flamborough Head to Portland Bill, splits the country in two geological parts. South East of this line there can be found no surface hard rock deposits. Ironically, however, over a third of UK demand is in the South East! For this reason the South East, while self-sufficient in supplies of sand and gravel, relies heavily on rail connected quarries, such as Lafarge's Mountsorrel Quarry in Leicestershire, to supply the hard rock demand.
Types of Aggregates
There are three main types of Aggregates used in the UK:
1, Crushed Rocks, including 450 millions year old solidifed molten rocks such as Granite, or sedimentary rocks created by settlement of organic remains eg limestone).
2, Alluvial aggregates, deriving from the erosion of particles transported by water or ice - such as silt and clay and larger particles such as sands and gravels.
3, Marine Aggregates, including sand and gravels, dredged from sea beds.
Increasingly, companies such as Lafarge are producing recycled or secondary aggregates created from crushed or demolished buildings, old road planings, or in the case of Envirosand, recyled, crushed bottles!