ASTM D441-86(1994)e1

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Designation: D 441 – 86 (Reapproved 1994)
Standard Test Method of
Tumbler Test for Coal
This standard is issued under the fixed designation D 441; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Section 10 was added editorially in November 1994.
1. Scope pulverizing coal samples for analysis. The jar shall be fitted
inside an iron frame with lifting shelves constructed as shown
1.1 This test method covers the determination of the relative
in Fig. 1. The two rings, a, shall be 7 ⁄8 in. (181 mm) in outside
friability of a particular size of sized coal. It affords a means of
3 1
diameter and shall be made of ⁄4-by ⁄8-in. (19- by 3-mm) iron.
measuring the liability of coal to break into smaller pieces
1 3 1
The three ledges or shelves, b,6 ⁄2 by ⁄4 by ⁄8 in. (165 by 19
when subjected to repeated handling at the mine or subse-
by 3 mm), shall be attached radially to the rings by means of
quently, by the distributor or by the consumer. This test method
small brackets, c, the ends of the shelves being flush with the
is serviceable for ascertaining the similarity of coals in respect
outer edges of the rings. The shelves shall be attached so that
to friability rather than for determining values within narrow
there will be ⁄8-in. (15.9-mm) clearance between their outer
limits to emphasize their dissimilarity. This test method also
edge and the outside of the ring. Rivets, not bolts, shall be used
may serve to indicate the relative extent to which sized coals
in constructing the frame. As the jars available commercially
will suffer size degradation in certain mechanical feed devices.
are not of absolutely uniform size, the measurements of the
This test method may be used for differentiating between
frame may be slightly varied to suit individual cases. The frame
certain ranks and grades of coal, and therefore the test method
shall be fixed inside the jar by means of wedges between the
is of service for coal classification purposes.
rings and the inside wall of the jar so that its axis shall coincide
1.2 The values stated in inch-pound units shall be regarded
as nearly as possible with the axis of the jar, and so that the
as the standard. Mass may be expressed in metric values.
frame will rotate with the jar. The jar shall be closed by a set-in
1.3 This standard does not purport to address all of the
porcelain lid resting upon a heavy rubber gasket and sealed
safety concerns, if any, associated with its use. It is the
tightly according to the customary procedure with such jars,
responsibility of the user of this standard to establish appro-
that is, by means of a bolt working against the lid. The bolt
priate safety and health practices and determine the applica-
shall be set in a crossbar, the ends of which shall be held by a
bility of regulatory limitations prior to use.
metal strip which fits around the body of the jar. For tumbling,
2. Referenced Documents
the jar shall be laid in a horizontal position in a suitable support
or rack and rotated about its cylindrical axis at the rate of 40
2.1 ASTM Standards:
rpm. The assembled apparatus is illustrated in Fig. 2.
D 410 Method for Sieve Analysis of Coal
4.2 Optional Iron Jar Tumbler—An iron jar may be substi-
E 11 Specification for Wire-Cloth Sieves for Testing Pur-
tuted for the porcelain jar specified in 4.1, provided it has
poses
approximately the same internal dimensions, namely, 7 ⁄4 in. in
3. Significance and Use
diameter by 7 ⁄4 in. in depth. A jar constructed of cast iron is
recommended, and the interior machined to the required
3.1 This test method is a measure of the resistance of the
internal dimensions. For making it sufficiently light for lifting,
coal to breakage upon impact and abrasion as the coal rubs
the jar may have a wall thickness of not less than ⁄4 in. (6.35
together and against the walls of the transportation vehicle.
mm), except at each end. It is recommended that the lid, rubber
4. Apparatus
gasket, and the metal strip that passes from the bottom up the
outside of the jar to serve in holding in place the crossbar above
4.1 Porcelain Jar Tumbler, consisting of a cylindrical por-
the lid, be similar in design with those for the porcelain jar. The
celain jar of uniform dimensions, 7 ⁄4 in. (184 mm) in diameter
wall of the iron jar for a distance of approximately 1 in. (25.4
and 7 ⁄4 in. in depth, inside measurements, such as is used for
mm) from the top shall have a thickness of at least ⁄2 in. (12.7
mm) to correspond with that of the porcelain jar; and in order
This method is under the jurisdiction of ASTM Committee D-5 on Coal and
that the metal strip may fit evenly, the lower inch of the wall
Coke and is the direct responsibility of Subcommittee D05.07 on Physical
Characterization and Beneficiation of Coal and Coal Slurries.
should also have a thickness of not less than ⁄2 in.
Current edition approved Sept. 26, 1986. Published November 1986. Originally
4.3 Sieves—For sizing the sample for test, square-hole
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published as D 441 – 37 T. Last previous edition D 441 – 45 (1980) .
2 sieves having 1.50- and 1.06-in. (38.1- and 26.9-mm) actual
Discontinued; see 1988 Book of ASTM Standards, Vol 05.05.
Annual Book of ASTM Standards, Vol 14.02. openings between the wires shall be used. These sieves may be
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D 441
5. Sampling
5.1 Collection of Gross Sample—Collect the gross sample
of coal in accordance with Section 5 of Method D 410.
5.2 Preparation of Sample:
5.2.1 Make a preliminary sieving of a representative por-
tion, approximately 100 lbs (45 kg), of the gross sample, using
square-hole sieves with 1.06- and 1.50-in. (26.9- and 38.1-mm)
openings. If this preliminary sieving indicates that the pieces of
coal are mostly smaller than 1.50 in., sieve successive repre-
sentative portions of the gross sample until at least 25 lbs (11
kg) of the 1.06- to 1.50-in. size are obtained. If most of the
pieces obtained by the preliminary sieving are larger than 1.50
in., conduct sieving of representative portions of the gross
sample until at least 50 lbs (23 kg) of the sieved material
remaining on the 1.06-in. sieve are available. Then break the
pieces so obtained that are larger than 1.50 in. with a hammer
until they pass the 1.50-in. sieve, avoiding as much as possible
the production of pieces smaller than 1.06 in. Should the
combined weights of the 1.06- to 1.50-in. size, obtained by
Metric Equivalents
sieving before and after hammer breakage of the larger pieces,
1 5 3 1 1
in. ⁄8 ⁄8 ⁄4 6 ⁄2 7 ⁄8
be less than the required 25 lbs, augment the amount by further
(mm) (3.18) (15.9) (19.0) (165) (181)
sieving and breakage of additional representative portions, or
FIG. 1 Steel Frame Used in Jar Mill
the remainder of the gross sample, taking care to discard all
pieces in which noticeable cracks have developed by hammer
breakage. Take care also to provide pieces covering the whole
range of the 1.06- to 1.50-in. size in both the 25-lbs composite
sample, and in each 1000-g sample taken for test as in Section
5. This may be accomplished by the use of a 1.25-in.
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