Palmer Coking Coal Company sells seven (7) main types of crushed
gravel products. We thought many of our customers might find it
useful to know more about these products and how they can best fit
your usage applications. Our seven crushed gravel products from
largest to smallest are:
2” MINUS CRUSHED SINGLE PASS
This product is similar to railroad ballast, but with more fines.
By single pass, we mean that the product passes through a rock
crusher a single time. This product is created by crushing large
gravel, rocks, and stones with the resulting sieve (i.e. the size
consist of the product) being predominantly 2” and below, with a
few pieces that are slightly larger. This product is very coarse
and has about 15% fines. It’s a great product for firming up a
muddy site or for an interim or final application for use by large
trucks or equipment.
1-1/4” CLEAR CRUSHED GRAVEL:
This product is crushed and then screened so that the product is “Clear” of
most fines and known as 1-1/4” Clear. It is a very coarse
crushed gravel with most of the particles in the 1-1/4” to ˝”
size. It generally has about 5% fines (i.e. sandy binder).
Because it lacks fines, it does not pack as well as a State Spec.
1-1/4” crushed gravel. Many customers find this very coarse
crushed gravel useful in soft or muddy situations where too many
fines would do little to firm up the soft or muddy conditions.
This product can also be used in a situation where you want a
crushed gravel that is free of fines and will still drain.
STATE SPEC. 1-1/4” MINUS CRUSHED SURFACING
BASE COURSE (CSBC): Our 1-1/4” State Spec. crushed gravel is
your traditional base course product for the construction of
streets and roads. In the usual road-section example, 4” of
1-1/4” State Spec. is placed below 2” of 5/8” State Spec. and
after compaction, the road-section is paved. 1-1/4” State Spec.
contains 40 – 50% fines (i.e. 3/8” minus) and thus packs quite
well. It’s a good driveway gravel where a firm base has already
5/8” CLEAR CRUSHED GRAVEL: Our
5/8” Clear is similar to our 1-1/4” Clear, but with a smaller top
size. 5/8” Clear is the largest sized and the coarsest of our
three 5/8” sized products and generally has about 5% fines (i.e.
sandy binder). Most of the rocks will be around 5/8" in size with
some larger and some smaller sized rocks. Because it lacks fines,
it does not pack as well as either a State Spec. 5/8” crushed or
our Homeowner’s 5/8” crushed. Many customers will use this
product in a soft or muddy situation where they want a finished
appearance. If conditions are right, the very coarse (95% crushed
gravel) will embed itself into the softer ground where it is being
used. This product can also be used in a situation where you want
a crushed gravel that is free of fines and will still drain.
HOMEOWNER’S 5/8” CRUSHED GRAVEL:
Our Homeowner’s 5/8” was developed to serve the homeowner market.
This product is something of a compromise between the State Spec.
5/8”, which has about 60% fines or sandy binder and the 5/8” Clear
which has only 5% fines. The Homeowner’s 5/8 has about 20-30%
fines. While it still packs (though not as well as State Spec.
5/8”), it also shows a lot of the larger sizes of crushed gravel.
Many homeowners’ appreciate a slightly coarse product that shows a
lot of rocky crushed gravel but still packs.
STATE SPEC. 5/8” MINUS CRUSHED SURFACING TOP
COURSE (CSTC): Our 5/8” State Spec. crushed gravel is your
traditional top course product for the construction of streets and
roads. In the classic example of a road cross-section, 2” of State Spec.
5/8” is placed above 4” of 1-1/4” State Spec. and after compaction
the road base is paved. 5/8” State Spec. contains about 50 - 60%
fines (i.e. sandy binder) and thus packs quite well. It’s a good
driveway gravel where a firm base has already been established.
1/2” MINUS MAINTENANCE GRAVEL: This
is a cheaper alternative to traditional State Spec. 5/8"
crushed gravel. It's a slightly smaller size with a bit more
sand and a bit more round, partly crushed gravel. It packs
well and will meet WSDOT Spec. 9-03.9(4) Maintenance Rock.
3/8” MINUS CRUSHED GRAVEL: This product
is the finest (i.e. smallest top size with the most fines) of our
crushed gravels. It is almost all crushed product. Because some
of the particles are so small, they are similar in size to sand.
It has a fairly consistent sieve analysis with fairly equal parts
of the particle sizes of 3/8” and below. 3/8” Crushed packs very
well and has often been used in trail construction or in any
situation where a small size product that produces a hard packed
surface is wanted
IMPORTANT NOTES: A gravel mining operation is a dynamic
process. As we move through our pit, the raw particle sizes
change which changes the exact sieve analyses (i.e. the
particle sizes), that make up our products. We generally
have recent sieve analyses of our product.
If you need a copy of a sieve analysis, please call our office and
request one. If you would like to compare and contrast these
products, we have sample buckets at our office with all the
products displayed. If you have any questions about any of these
products, please ask. Also, when you or your truck-drivers are
ordering your products, please be specific. If you want 1-1/4”
Clear, please ask for 1-1/4” Clear. There is a danger that if you
simply ask for 1-1/4” you might receive the more common 1-1/4”
State Spec. rather than the more specialized 1-1/4” Clear. The
same is particularly true for 5/8” where we have three types of
5/8”: the finer State Spec. 5/8”; the larger Homeowner’s 5/8”; and
the largest 5/8” Clear. Please be specific in your order.
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