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Sampling from carload shipments of
fine bulk materials
One established method for sampling a
carload of bulk granular material is to take
eight equal samples, (approximately 700 to
1000 grams each) from the bottom of a
30.48 cm
(1 foot)) conical excavation.
Samples should be suitably spaced to
represent the length and width of the car
and then combined into a single gross
sample.
Sampling
bulk
material with a sampling tube
An alternate and simpler method of
sampling a carload, or other bulk quantity
of fine or granular material is by use of a
sampling tube which, for this purpose,
should be 38.1 mm (1 1/2 inches ) by
approximately 1.829 m (6 feet ). Five or
six insertions of the tube will produce
approximately, a 2 pound (907g) sample.
Sampling from a carload of bagged
material
One method of sampling a carload of
material shipped in bags is to select, at
random, a number of bags equal to the
cube root of the total number of bags in
the car and to take suitable portions (800
to 1000 grams for minus 6 mm material)
from each of the selected bags for a
combined gross sample.
Sampling from a pile
In sampling from a pile, particularly
material
like
crushed
containing large particles, it is extremely
difficult to secure samples that are truly
representative. At the apex of a conical
pile, the proportion of fines will be greater,
while at the base; the percentage of coarse
particles will be greater. Therefore, neither
location will be representative of the whole.
In a shoveling process, every fifth or tenth
shovel, etc., should be taken depending on
the amount of the sample desired. The
sample should consist of small quantities
taken at random from as many parts of the
pile as are accessible and taken in a
shipments
of
stone
or
manner that the composite will have the
same grading as the larger amount.
Reduction of gross sample to test size
for sieve analysis
After
properly obtained, the next step is to
reduce it to a suitable size for sieve
analysis without impairing in any way the
particle size distribution characteristics of
the original sample. This phase of the
operation
fine
procedures described in the succeeding
sections and should be performed with as
much care as was used in the collection of
the gross sample and in performing the
sieve test.
Coning and quartering
Pile the gross sample in a cone, place
each shovel full at the apex of the cone,
coal
and allow it to run down equally in all
directions. This will mix the sample. Then
spread the sample in a circle and walk
around the pile, gradually widening the
circle with a shovel until the material is
spread to a uniform thickness.
Mark the flat pile into quarters, and
reject two opposite quarters. Mix again into
a conical pile, taking alternate shovel-fulls
from the two quarters saved. Continue the
process of piling, flattening, and rejecting
two quarters until the sample is reduced to
the required size.
the
gross
sample
should
follow
the
has
been
applicable
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