Within Indiana, over a billion dollars worth of material is mined from the ground every year, primarily from mining coal and limestone. Quarrying of the rock limestone and gravels(which is a rock, not a mineral) is the primary form of industrial resource extraction after coal. Often rocks are lumped with minerals and both are called "mineral resources"--just to make life confusing. So even though limestone and coal are types of rocks, they are considered "mineral resources."
The mineral resources and mining within Indiana are of entirely mundane, non-glamorous resources. Precious metals and gemstones are not mined in Indiana---because they are non-existant or extremely rare.
The contribution of mineral and rock resources to Indiana's economy. In this section we will discuss crushed stone, cement, dimension limestone, and sand and gravel.
What Can You Mine in Indiana?
In this section we will go over the mining of industrial minerals and fuels, while in the next section we will review the coal mining industry. Below are definitions for each of these "mineral" commodities mined or quarried in Indiana.
Portland Cement
Cement is primarily derived from the mining of calcium carbonate, which is the mineral calcite. The calcite is derived from limestone that has a very high concentration of calcite. The limestone is crushed into a fine powder and used as the main ingredient at a cement plant. This crushed lime is also used as a fertilizer.
Dimension Limestone
This is limestone used for decorative purposes. Indiana is most famous for this type of limestone, which is used in the facades of many famous buildings like the Pentagon, Empire State Building, and the IUPUI University Library. Good dimension stone limestone has to be free of fractures, fossils, geologic imperfections, and have a consistent chemistry that lacks iron. Generally, it is massive and uniform in color, which is required when being used to decorate a building.
Crushed Stone
Crushed stone or aggregate is a primary ingredient in concrete (which is a mixture of sand, cement, and aggregate). It is also used in applications where gravel or rip-rap (large chunks of rock) are required. A key factor of aggregate is that it is rigid (it won't break apart) and it lacks chemical elements that will react with water or the atmosphere.
The aggregate used in concrete varies from state to state, depending on what rock is locally available that meets the requirements. In Indiana, limestone is also used as aggregate. Aggregate stone can have more impurities than limestone used for concrete, but still a relatively pure limestone of almost all calcite is desired.
Sand and Gravel
Sand and gravel is typically mined from river or glacial deposit that have a high concentration of sand and gravel sized particles. Sand and gravel describe the grain size of the material, not its lithology--or mineralogical content. In Indiana, almost all sand and gravel quarries are mined in glacial deposits in former river valleys that were present during former glacial times. Sand is used as an ingredient in concrete, components of cement, and in mortar, which is used in brick laying. Gravels are often used in concrete, construction site preparation, and special applications like traction control on snowy roadways.
Miscellaneous
Other resources mined in Indiana include a limited amount of natural gas and oil, but it is a very minute amount. Clay is mined and used in applications like adding glossiness to magazine pages, make up, paints, and kitty litter. Gypsum is mined in several locations in southwest Indiana and used in the production of wall board.
One miscellaneous resource I'd like to mention is methane gas, which can easily be processed into natural gas. Methane gas is ofted tied up in coal deposits, and can be extracted from coal deposits. In the past 5 years, coal bed methane extraction has increased drastically, causing companies to develop gas fields in Appalachian coal beds and coal found in Indiana and Illinois.
Coal
This resource will be discussed in the last section.