Crushed Stone Aggregate Resources of Indiana

Abstract

Mineral aggregate is an aggregation of mineral material, such as crushed rock, expanded shale, perlite, sand and gravel, shells, or slag. It is sometimes bound with such material as cement or asphalt or is sometimes not bound for use as filter stone, flux stone, railroad ballast, riprap, or road metal. Crushed limestone and dolomite, sand and gravel, slag, perlite, and expanded shale are the main natural and fabricated aggregates currently used in Indiana. Some aggregate, such as sand and gravel, requires little or no processing and can be used almost as it is mined, but rock must be crushed and sorted into various desired sizes before it can be used. Many types of rocks can be used for crushed stone aggregate, but limestone and dolomite are used exclusively in Indiana (pl. 1). In this report crushed stone is synonymous with crushed limestone and dolomite. Each type of aggregate has a distinct advantage with respect to cost and availability or to a specific use for which one type is more suited than another. The advantages of crushed limestone and dolomite are that they can be crushed and sized to meet most specifications, the materials are clean and angular and bind well with cementing mixtures, a uniform lithologic composition can be maintained with little or no selective quarrying in many areas, and they are available at low cost in most counties in Indiana. Crushed stone is one of Indiana’s most important mineral commodities, ranking third in annual value behind coal and cement. During 1969 crushed stone production in Indiana totaled 25, 516,000 tons and was valued at $34,418,000.