Sand and gravel

Sand and gravel from Tarmac's quarries

Sand and Gravel is defined as 'loose collections of the more durable rock fragments released from their parent rocks during weathering'. These can be deposited in layers by wind, glacier flows, rivers or marine actions or ice.

Sand quarries are shallow, sometimes only 5 or 6 metres deep. Operations are likely to be of a shorter term than for a rock, limestone or gritstone, quarry with progressive restoration normally following closely behind extraction. The working area at any time is usually comparatively small.

Sand and gravel deposits are commonly found in the south east of the UK. The fundamental difference between sand and gravel is the particle size, anything that passes through a 2mm sieve and is retained on a 63 micron sieve is classed as sand, with all particles retained on the 2mm sieve classed as gravel.

The rounded shape is the most noticeable characteristic of gravel, however, this shape can provide poor aggregate interlock in asphalt mixtures and this is why crushed aggregate is preferred. In concrete mixtures the smooth texture of gravel can provide a greater level of workability.