There are about 200 stone quarries in Illinois. Most of the larger
quarries (fig. 3) are in the Chicago, Joliet, Kankakee, and East St.
Louis areas, but one or more limestone or dolomite quarry occurs in many
counties.
If all the stone taken from Illinois quarries in 1963 were removed from
a hole 100 feet square, the hole would penetrate into the earth about 8
miles. It would take more than 350,000 railroad cars holding 100 tons
each to haul away the stone. Limestone, dolomite, and their products
added over 80 million dollars to the economy of the state in 1963,
approximately 8 dollars for each person in Illinois.
Most Illinois limestone and dolomite is quarried from open pits, but in
some places, as in the rocky bluffs along the Mississippi River, the
stone is taken from underground mines (fig. 4). There is also a dolomite
mine in Chicago. At the quarries the first step is the removal of the
earth overlying the stone. Next, in both pit and mine, the stone is
blasted to free it from the parent deposit and break it into pieces.
Mechanical shovels (fig. 3) load the stone into trucks that take it to
the crushing plant where powerful crushers further break the stone into
pieces. The pieces are sorted into various sizes by large screens. At
some of the plants, the stone is ground into powder.