There are approximately 350 large commercial quarries operating throughout Ireland. There are two main types – rock quarries and sand and gravel pit quarries.
Rock quarries are usually deep quarries and are operated on several different levels or “benches”. The first production stage is usually a carefully controlled explosion that releases and breaks up the rock into large lumps. A large truck or conveyor then takes it to a powerful crusher where it is broken down into aggregates and separated into different sizes.
Sand and Gravel Pits
Sand and gravel pits are shallower than rock quarries because the deposits are usually less than the equivalent of one bench of a rock quarry. The material is excavated with a mechanical shovel and is then carried by conveyor to a plant where it is crushed, washed and screened into different sizes.
Rocks as Aggregates
“Aggregate” is the term used for rock that has been broken into small pieces, either by nature or by people. Aggregates consist of two main types -crushed rock and sand and gravel. Aggregates are one of the world’s great natural resources. Ireland is rich in its reserves of aggregates. First used by settlers and farmers to fence their lands 5,000 years ago, stone and aggregate is as essential to our economic success and development as any other natural resource such as oil, water and food. Our roads and motorways, homes, schools, hospitals, colleges, factories, water and sewerage systems are all built from concrete, 80% by weight of which is aggregate.