History of Aggregates - CEMEX USA
Every year more than 10 tons (or 20,000 pounds) of sand, gravel and stone is mined for every person in the United States. These materials are used to make or repair roads and highways, sidewalks, houses, schools, offices, stores, factories and other buildings that each of us use daily.
The average new house contains 120 tons of sand, gravel and stone. About 17 tons is used in concrete.
85,000 tons of aggregates are necessary to construct one mile of an interstate highway or ¼ mile of a four-lane road.
Content provided by the Mineral Information Institute, © 2002 mineralseducationcoalition.org
Aggregates are used to build highways, bridges, homes, schools and sidewalks. Your driveway may be made of concrete or crushed stone. Your house may be constructed of brick or stone. The sidewalk near your school is probably made of concrete. We call the aggregates used for building "construction aggregates". Some aggregates are also used in agriculture and manufacturing.
The first step in any type of mining is removing rock from the ground. To begin, any unusable rock and soil (called "overburden") covering the orebody is removed and stockpiled for later use. Depending on how hard or loose the rock to be mined is, it may be removed by either dredging, digging or blasting.
The United States alone uses more than 2 billion tons of aggregate each year.
How big is a boulder?
- Boulder: More than 10 in. (254mm) in diameter
- Cobble: From 2.5 to 10 in. (64 to 254mm) in diameter
- Pebble: From .16 to 2.5 in. (4 to 64mm) in diameter
- Granule: From .08 to 0.16 in. (2 to 4mm) in diameter
- Grain: From .04 to .08 in. (1 to 2mm) in diameter
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