Coking Coal Company markets several types of clay and
silty sand products. Our
primary clay product is a basic Gray
Clay composed of fine sands, silt, and clay.
In characterizing soil, the “size consist” of
the soil particles determines how the soil is classified.
Sands are the larger particles and for that reason
are generally better drained.
Next comes silt, while the finest or smallest
particles are the clay fraction.
The greater the amount of clay, the less permeable
the soil and the harder it packs.
With clay, like most products, there is a tradeoff
between purity and ease of handling. Without
some sand and silts, pure clay when wet would be very
“sticky” and difficult to work.
The inclusion of some sand and silt makes the clay
soil more workable and improves its flow characteristics.
A good way to think of flow characteristics is to
contrast the way sugar or salt flows as compared to the
way very fine flour or corn starch might flow.
Clay is useful in a number of applications
where the user needs a hard packed material with low
percolates through clay soils very slowly when compared to
a rapid permeability material such as drain gravel.
Applications for our clay products include
compaction grouting, horse stalls, BMX bike trails, a
barrier soil liner for ponds, ditches, landfills, streams,
or as a soil or soil amendment where a denser clay
consistency is required.
sieve or particle size analyses for our Gray Clay is shown below (product sieve
sizes can change so please call for our most recent
Unique Characteristics of Clay
by Alfred R. Conklin, Jr.
Soil is made up of three
different size solids - sand, silt, and clay.
Of these, the smallest are the clay
particles. Though many soils contain gravel, rock,
and boulders, all contain sand, silt, and clay.
Here however, we are only thinking of the
clay fraction. Soils
are said to be “clayey” over a broad range of
clay contents. Any
soil with a clay content of 30% or more will have
clay as part of its textural name.
Clays, along with organic matter, are highly
active both chemically and physically.
It is this high reactivity that makes clay an
important consideration in all the uses to which we
wish to put soil.
are not smaller versions of sand or silt particles
which are primarily silica.
They are formed chemically by substitution or
rearrangement of primary minerals, or by
crystallization of aluminum and silicon oxides from
the soil solution.
Soil contains many different types of clays.
The important differences are not in size but
in chemical make up, crystal arrangement, and
Clayey soils have high water holding capacity
and low to extremely low hydraulic conductivities.
They also have high chemical reactivity.