An overview of aggregate resources in the United States

摘要

In 2000 the USA produced about 2.7 billion tonnes of aggregate worth about $13.7 billion. Both crushed stone and sand and gravel are produced in virtually every State, although limited quantities are available in the Gulf Coastal Plain, the Colorado Plateau, the Wyoming Basin and the Great Plains. Prices vary depending on the product and location. Most aggregates are transported by road, and minor amounts by railroad, barge on navigable inland channels, and through the Great Lake ports. Imports and exports of aggregates are very minor. A major amount of crushed stone aggregates is consumed by public projects, mostly for highway and road construction and maintenance. A significant amount of sand and gravel is used for concrete aggregate. Recycled aggregates account for about 8% of total demand, although the amount recycled is thought to be increasing. Current issues facing the industry include the differences in quality specifications between States, adjusting to the increasing concern for the impact of aggregate mining on the environment, health issues from paniculate matter and crystalline silica, and the complexity of obtaining permits for extraction. Reduction in the number of companies extracting aggregates is likely to occur through acquisitions.