Limestone quarry in Kentucky.
Limestone, a sedimentary rock mainly composed of calcium carbonate, is an important resource in Kentucky. It is the principal source of crushed stone used in construction, agriculture, and a variety of industries. Some limestones have been altered by magnesium-rich fluids to form dolostone, also a source of construction stone. Dolostone is composed of the mineral dolomite, calcium magnesium carbonate.
Limestone and dolostone are at the surface in 25 percent of Kentucky, generally in the Blue Grass, Knobs, and Mississippian Plateau (Pennyroyal) Regions. In some parts of the State where surface deposits are absent, limestone and dolostone are beneath the ground at a mineable depth.
The principal limestone deposits of Kentucky were laid down in warm, shallow seas, from 460 million to 330 million years ago during the Ordovician, Silurian, and Mississippian Periods. Most of the Silurian limestones have been altered to dolostone, but Ordovician and Mississippian rocks also contain some dolostones.
Limestone was originally deposited as limey sediments in a shallow tropical sea in conditions similar to those of the present-day Bahamas Platform. After the limey grains were deposited, they were cemented together, usually by calcium carbonate (the mineral calcite). When the grains became cemented, the sediments became limestone.
In 1992, Kentucky was the fifth-largest stone producer among the 50 states. Kentucky has achieved its position as one of the Nation's major producers by supplying large quantities of limestone and lime to out-of-state markets in the Ohio River Valley and the Gulf Coast region.
Kentucky produced 58.8 million short tons of limestone and dolostone in 1992.
Kentucky's 1992 stone production had a value of $251.1 million, averaging $4.25 per ton.
Stone is being produced at 72 open-pit quarries and 17 underground mines in 62 of the State's 120 counties. In recent years, a western Kentucky quarry has been the top producer in the United States. The quarry in 1992 produced 10.2 million tons of stone.
Construction, the largest market for crushed stone produced in Kentucky, includes aggregate for road construction and maintenance, and for residential, commercial, and government construction; riprap and jetty stone; and railroad ballast. Industrial and miscellaneous applications include chemically pure stone for the manufacture of lime and cement; filter stone; sorbent stone for removing sulfur dioxide emissions from coal-burning plants; rock dust for explosion abatement in underground coal mines; chemical stone; and acid-water treatment. Agricultural uses include limestone applied to soils to adjust their pH; poultry grit; and mineral feed.
The second- and third-largest lime plants in the United States are in Kentucky, along the Ohio River in Mason and Pendleton Counties. Lime is manufactured from Ordovician limestones for flue-gas desulfurization, steel and chemical industries, and water treatment.
For further information on limestone resources in Kentucky, contact Dr. Warren Anderson , Kentucky Geological Survey (606-257-5500).
Other information about limestone can be found by contacting the following organizations:
Kentucky Crushed Stone Association (502-223-2379)