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Natural rock aggregate is crushed stone and sand and gravel, all used as the raw material in construction, agriculture, and the chemical and metallurgical industry. Aggregate is found in roads, bridges, bricks, concrete, wallboard, glass, plastic, paper, and medicines such as "Tums" or "Rolaids!" According to a USGS publication Natural Aggregates-Foundation of America's Future (February, 1999), aggregate is produced in every state and the U.S. crushed stone aggregate production, by kind of stone, is made up of:
According to Stone in Missouri, a publication of the Missouri Department of Natural Resources, Division of Geology and Land Survey, Rolla, MO (1/22/99), the use of stone in Missouri breaks down to:
The remainder is not reported, although it is believed to be used mostly as rock aggregate. In 1997, Missouri stone production exceeded 79 million tons and this plus cement and lime products manufactured from stone account for 70 percent of the state's mineral industry. The aggregate comes from a rock quarry such as the Capital Quarries operation near Sullivan, Missouri. After this site was deemed suitable, a quarry and plant was developed.
Moments after this image (see above) was taken of the Petosi Dolomite, the site was blasted (see below!).
Photo date 6/27/2000; © by S.W. Aber
Cathy Wilcox and Carol Combs were among the Missouri teachers present at the quarry (see below).
Photo date 6/27/2000; © by S.W. Aber
After the rock is liberated the front loader moves the rock to the crushers.
Photo date 6/27/2000; © by S.W. Aber

Crushed rock is moved by conveyor belts and screened for different sizes of stone.
Photo date 6/27/2000; © by S.W. Aber
The crushed and sized aggregate is loaded into the dump truck, weighed, and the deposited in piles according to size and customer needs.
Photo date 6/27/2000; © by S.W. Aber
This image shows aggregate gradations (from left to right)of 5/16 inch, 1/2 inch, and 3/8 inch, with larger gravel and cobbles behind the seived piles and the natural outcrop of dolomitic limestone in the background.
Photo date 6/27/2000; © by S.W. Aber
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Created July 10, 2000; last update, June 9, 2005. © 2000-2005 Susan Ward Aber. All rights reserved.