Distribution and quality of potential sources of aggregate infrastructure resources project area, Colorado-Wyoming

Crushed stone and sand and gravel are the main types of natural
aggregate used in the United States. Aggregate is used in nearly
all residential, commercial, and industrial building construction,
and in most public works projects including roads and highways,
bridges, railroad and light rail beds, airports, water and sewer
systems, and tunnels. Much of the infrastructure built during the
1950s and 1960s has deteriorated to a point that requires extensive
repair or replacement. All this construction requires enormous
amounts of aggregate. In Colorado, for example, nearly 45 million
tons of aggregate, or about 12 tons per person, were produced
during 1994.