Indiana Geological Survey Bulletin 42-HMineral 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.Indiana Department of Natural Resource
