Aggregate Mining
Construction aggregate, or simply aggregate, is a broad category of coarse- to medium-grained particulate material used in construction. Traditionally, it includes natural materials such as sand, gravel, crushed stone. As with other types of aggregates, it is a component of composite materials, particularly concrete and asphalt. Aggregates are the most mined materials in the world,[1][2] being a significant part of 6 billion tons of concrete produced per year.[3]
Aggregate serves as reinforcement to add strength to the resulting material. Due to the relatively high hydraulic conductivity as compared to most soil types, aggregates are widely used in drainage applications such as foundation and French drains, septic drain fields, retaining wall drains, and roadside edge drains. Aggregates are also used as base material under building foundations, roads, and railroads (aggregate base). It has predictable, uniform properties, preventing differential settling under the road or building.
Aggregates are also used as a low-cost extender that binds with more expensive cement or asphalt to form concrete. Although most kinds of aggregate require a form of binding agent, there are types of self-binding aggregate which require no form of binding agent.[4] More recently, recycled concrete and geosynthetic materials have also been used as aggregates.
Essex (/ˈɛsɪks/) is a county in the East of England. One of the home counties, it borders Suffolk and Cambridgeshire to the north, the North Sea to the east, Hertfordshire to the west, Kent across the estuary of the River Thames to the south and Greater London to the south and south-west. The county town is Chelmsford, which remains the only city in the ceremonial county until Southend-on-Sea is formally accorded city status. For the purposes of government statistics, Essex is placed in the East of England region.[3][4]
There are four definitions of the extent of Essex, the widest being the ancient county. Next largest is the former postal county, followed by the ceremonial county with the smallest being the administrative county – the area administered by the County Council, which excludes the two unitary authorities of Thurrock and Southend-on-Sea and the areas administered by the Greater London Authority.
The ceremonial county occupies the eastern part of what was, during the Early Middle Ages, the Anglo-Saxon Kingdom of Essex. As well as rural areas, the county also includes London Stansted Airport, the new towns of Basildon and Harlow, Lakeside Shopping Centre, the port of Tilbury and the borough of Southend-on-Sea.