The Mineral and Fuel Industry of Indiana

[Mineral and Fuel Industry Chart]

Mineral and fuel commodities mined in Indiana include common clay and shale, limestone and dolomite, construction sand and gravel, industrial sand, sandstone, gypsum, peat, and coal. Depending on the quality and type of limestone, it may be sold as dimension stone for construction of buildings, crushed for use as aggregate, or used in the production of concrete or cement. Crushed stone is also processed into agricultural lime or used for sulfur dioxide removal in coal-fired electric power plants with limestone scrubbing systems or may be finely ground for use as fillers in various products.

In addition to agricultural lime, some stone is imported from Michigan and processed by two northern Indiana companies into lime used mostly by the steel industry on Lake Michigan. Dolomite is sold as crushed stone. Some has been sold as decorative dimensional stone. A small quantity of sandstone is produced on demand for small landscaping or construction projects.

The clay and shale produced in Indiana is primarily used for cement, concrete blocks, tiles, animal feed, absorbents, plastics, adhesives, or paint. Gypsum is primarily used in production of wallboard and cement. Peat is used for soil improvement, on golf courses, for earthworm culture and by nurseries. Construction sand and gravel is used mostly for concrete aggregate, roadbase and road stabilization, fill, for asphaltic concrete and for snow and ice control. Industrial sand is used for refractory purposes and by foundries for molding, for blasting, and in glass manufacture. A small quantity of freshwater pearls are also harvested in Indiana. Approximately 89 percent of all coal produced in Indiana is burned in coal-fired electric power plants, 10 percent powers industrial plants, and 1 percent goes for residential use. Oil and natural gas are also extracted from many wells in Indiana.

Underground Coal Mining in Indiana

[Underground Coal Mining Chart]

Underground coal mining began in Indiana in the early 1830's. With the coming of the railroads, the number of underground mines grew rapidly in the late 1800's and early 1900's. Peak coal production of 29 million tons came in 1918 because of the demand created for coal by World War I. With improved surface mining since the 1920's, underground mining declined, so that today about 2 percent of Indiana's coal comes from underground mines.

About 900 million tons of coal has been produced in Indiana by underground mining. The total area undermined is more than 100,000 acres, or about 150 square miles, mostly in Vermillion, Vigo, Sullivan and Knox Counties. Mines have ranged from one-person operations to mines employing hundreds of workers. The state's largest mine - more than 9 square miles - was King's Station Mine in Gibson County south of Princeton. It closed in 1972.

[Surface-Mined Land in Indiana]

Surface-Mined Land in Indiana

More than 160,500 acres have been disturbed by surface mining for coal in Indiana. This mining has been limited to 21 counties in southwestern Indiana, mostly in Clay, Greene, Pike, Sullivan, Vigo and Warrick Counties.

Before the 1920's, nearly all coal produced in Indiana was mined underground. Since then the amount of coal produced by surface mining has gradually increased, so that now nearly all coal is mined in Indiana by stripping overburden from above the coal.

Early attempts to reclaim mined land were concurrent with large-scale mining, but these voluntary attempts were limited to reforestation. Indiana's first compulsory-reclamation law was passed in 1949. Reclamation has improved, so that in many places it is difficult to determine whether an area has been mined. Some land is considerably improved after surface mining.

By the 1950's many markets for Indiana coal had disappeared, but these losses were compensated by the increased use of coal by electric utilities. In 1980 about 80 percent of Indiana coal production was used to generate electricity

Distribution of Coal in Indiana

Our Indiana coalfields lie on the east edge of a broad, gently downwarped bedrock structure called the Illinois Basin (stippled area on map). Coal-bearing rocks are restricted to an area of about 6,500 square miles in southwestern Indiana because those that have existed elsewhere in Indiana have been removed by erosion.

[Distribution of Coal in Indiana]

Because of downwarping, the rocks dip to the southwest at 30 feet per mile, and each coalbed is at increasingly greater depth in that direction. The most active mining in Indiana has been in Vigo, Sullivan, Greene, Knox, Pike and Warrick Counties where the thicker and more widespread rocks of Middle Pennsylvanian age are near the surface. Most Hoosier coal is now strip mined, but vast resources of coal are available for underground mining.

Indiana Limestone

Indiana limestone or Bedford limestone is a common term for Salem limestone, a geological formation primarily quarried in south central Indiana between Bloomington and Bedford. Salem limestone, like all limestone, is a rock primarily formed of calcium carbonate. The limestone was deposited over millions of years as marine fossils decomposed at the bottom of a shallow inland sea which covered most of the present-day Midwestern United States.

The first Indiana limestone quarry was started in 1827, and by 1929 Hoosier quarries yielded 340,000 m* (12 million cubic feet) of usable stone.

[Indiana Limestone Company, Inc., Bedford]
Men working in a quarry of the Indiana Limestone Company, Inc., Bedford.

Buildings such as the Empire State Building, The Pentagon, and the United States Holocaust Memorial Museum feature Indiana limestone in their exteriors.

[Limey shale overlaid by limestone]
Limey shale overlaid by limestone.

Oil and Gas in Indiana

Trenton Field

The history of oil and gas development in the state of Indiana officially began in the mid-1800s with the early settlers' practice of drilling for salt water. Salt was a necessity for the preservation of foodstuffs and critical to the early state's agricultural industry; shallow wells were sunk in many parts of the state to obtain salt water that could be evaporated to produce salt. Drilling was probably accomplished by using a "spring pole" method. Early settlers also became aware of gas springs and oil seeps along the Ohio River in Harrison and Crawford Counties.

[Oil Well]

Following the news of the success of Colonel Edmond Drake's oil well in Titusville, Pennsylvania in 1859, oil exploration moved westward into Ohio and Indiana. Between 1862 and 1869, wells were drilled in Pulaski County and Vigo County and gas and oil were discovered but not further developed. Gas was discovered in what would become the Trenton Field near Eaton in Delaware County in 1876. Beginning in 1886 and continuing into the first decade of the 20th century, gas and then oil were discovered and developed in east central Indiana. A wild untethered boom ensued that ultimately resulted in thousands of wells being drilled; this was America's first giant oil field (greater than 100 million barrels of oil). The gas was used to attract and then fuel numerous industries in the region. In fact, the existence of Muncie, Anderson, Marion, and Kokomo as manufacturing centers can be directly attributed to the development of the Trenton Field. In addition to these industrial complexes, the oil boom led to the development of refining and petrochemical industries in the Calumet region. The boom quickly ended in the beginning of the 20th century because wasted resources and unregulated drilling practices caused a precipitous drop in production. Unfortunately much of the resource was wasted or lost through the burning of gas at the surface and the contamination of oil by fresh water within the subsurface reservoir.

Southwestern Indiana

As gas and oil production quickly declined in northern Indiana, new discoveries were being made in the southwestern part of the state known as the Illinois Basin. Production from fields in Vigo and Pike Counties was rapidly followed by new discoveries in Sullivan and Gibson Counties. Unlike the single field of northern Indiana that produced from a single reservoir, these new discoveries produced from many smaller fields and a variety of different reservoirs at different depths. Also, unlike the Trenton Field, the Illinois Basin fields produced mostly oil, not gas. Soon all the counties located in the southwestern part of the state were contributing to oil production. Production peaked in 1956 at over 12 million barrels for the year. Since that time both the number of holes drilled and the production for the state have declined. In 1997, Indiana produced just under 2.5 million barrels of oil and 526 million cubic feet of gas.

Current Activity and Future Prospects

Since the early 1960s, the amount of oil produced in Indiana has declined. Close examination of this decline reveals that changes in the price of oil are directly related to the number of wells drilled and consequently, the volume of oil produced. For instance, the reversal of the steep decline in the 1960s and 70s can be attributed to the energy crisis of 1973 and Iranian crisis of 1979. After 1986 a steep declined resumed, resulting from a dramatic lowering in the price of crude oil. In this same time frame, the number of holes drilled within the state has declined from over 1,200 in the early 1980s to around 200 in recent years. Most of these holes are drilled as development wells in existing fields in attempts to extract more oil. A low level of "wildcat" exploration still takes place within the state, but at an average price of $12 per barrel, exploration for new reserves is very limited.

There is a fair potential for the discovery of significant new reserves in the state. Much of the state has been drilled; however, this drilling reached only the first few thousand feet of depth. A considerable portion of the subsurface remains unexplored, and many thousands of feet of potential reservoir exist, especially in the southern portion of the state. Although the deep subsurface geology of this region is thought to be similar to northern areas of the state, details of thermal maturity, migration pathways, and trapping mechanisms are unknown. In addition to untested geology, the application of new technologies to explore for and produce oil and gas could hold the key to unlocking some of Indiana's resource potential. These new technologies, some of which are being used in the development of the New Albany Shale as an unconventional gas source, include the application of advanced seismic acquisition and processing techniques, new drilling technologies including horizontal drilling, and complex completion techniques such as liquid CO2 stimulation.

Gypsum, Clay, Sand and Gravel

Gypsum, one of the most widely used minerals in the world, literally surrounds us every day. Most gypsum in the United States is used to make wallboard for homes, offices, and commercial buildings; a typical new American home contains more than 7 metric tons of gypsum alone. Moreover, gypsum is used worldwide in concrete for highways, bridges, buildings, and many other structures that are part of our everyday life. Gypsum also is used extensively as a soil conditioner on large tracts of land in suburban areas, as well as in agricultural regions.

Gypsum deposits are in the NE and SW, and sand and gravel are found throughout the state.

Indiana is an important producer of masonry cement. Mining of gravel, gypsum, and stone is also commonplace in the central portion of southern Indiana.