Annex 3 Draft
New Test Procedure for Determining TML of Iron Ore FinesAppendix 2 Laboratory test procedures, associated apparatus
and standards
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Test procedures for materials
which may liquefy and associated apparatus
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"1.4
Modified Proctor/Fagerberg
test procedure for Iron Ore Fines
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1.4.1
Scope
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.1 The test procedure specified in this section
(this test) should only be used for be used for determining transportable
moisture limit (TML) of Iron Ore Fines. See individual schedule for
Iron Ore Fines.
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.2 Iron Ore Fines is iron ore containing both:
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.1 10% or more of fine particles less than 1 mm,
and
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.2 50% or more of particles less than 10 mm.
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.3 The TML of Iron Ore Fines is taken as equal
to the critical moisture content at 80% degree of saturation according
to the modified Proctor/Fagerberg method test.
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.4 The test procedure is applicable when the degree
of saturation corresponding to Optimum Moisture Content (OMC) is 90%
or higher.
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1.4.2
Modified Proctor/Fagerberg
test equipment
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.1 The Proctor apparatus (see figure 1.4.1) consists
of a cylindrical iron mould with a removable extension piece (the
compaction cylinder) and a compaction tool guided by pipe open at
its lower end (the compaction hammer).
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.2 Scales and weights (see 3.2) and suitable sample
containers.
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.3 A drying oven with a controlled temperature
interval from 100°C to maximum 105°C.
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.4 A container for hand mixing. Care should be
taken to ensure that the mixing process does not reduce the particle
size by breakage or increase the particle size by agglomeration or
consistency of the test material.
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.5 A gas or water pycnometry equipment to determine
the density of the solid material as per a recognized standard (e.g.
ASTM D5550, AS1289 , etc. )
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1.4.3
Temperature and humidity
(see 1.1.3)
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1.4.4
Procedure
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.1
Establishment of a complete
compaction curve
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A representative sample according to a relevant standard
(see section 4.7 of the IMSBC Code) of the test material is partially
dried at a temperature of approximately 60°C or less to reduce
the samples moisture to suitable starting moisture, if needed. The
representative sample for this test should not be fully dried, except
in case of moisture content measurement.
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The total quantity of the test material should be at least
three times as big as required for the complete test sequence. Compaction
tests are executed for five to ten different moisture contents (five
to ten separate tests). The samples are adjusted in order that partially
dry to almost saturated samples are obtained. The required quantity
per compaction test is about 2,000 cm3.
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Figure 1.4.1
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At each compaction test a suitable amount of water is added
to the sample of the test material. The sample material is gently
mixed before being allowed to rest and equilibrate. Approximately
one fifth of the mixed sample is filled into the mould and levelled
and then the increment is tamped uniformly over the surface of the
increment. Tamping is executed by dropping a 150 g hammer 25 times
through the guide pipe, 0.15 m each time. The performance is repeated
for all five layers. When the last layer has been tamped the extension
piece is removed and the sample is levelled off along the brim of
mould with care, ensuring to remove any large particles that may hinder
levelling of the sample, replacing them with material contained in
the extension piece and re-levelling. When the weight of the cylinder
with the tamped sample has been determined, the cylinder is emptied,
the sample is dried at 105ēC and the weight is determined. Reference
is made to ISO 3087:2011 "Iron ores -- Determination of the moisture
content of a lot". The test then is repeated for the other samples
with different moisture contents.
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Density of solid material should be measured using a gas
or water pycnometry equipment according to internationally or nationally
accepted standard, e.g. ASTM D5550 and AS 1289 (see subsection 1.4.2.5).
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.2
Definitions and data for
calculations (see figure 1.4.2)
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empty cylinder, mass in grams: A
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cylinder with tamped sample, mass
in grams: B
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wet sample, mass in grams: C
C = B A
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dry sample, mass in grams: D
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water, mass in grams (equivalent
to volume in cm3): E
E
= C D
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Volume of cylinder: 1000 cm3
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Figure 1.4.2
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.3
Calculation of main characteristics
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density of solid material, g/cm3 (t/m3): d
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dry bulk density, g/cm3 (t/m3): γ
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net water content, volume %: ev
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void ratio: e (volume
of voids divided by volume of solids)
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degree of saturation, percentage
by volume: S
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gross water content, percentage
by mass: W
1
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net water content, percentage by
mass: W
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.4
Presentation of the compaction
tests
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.5
Compaction curve
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The test sequence results in a specific compaction curve
(see figure 1.4.3).
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The critical moisture content is indicated by the intersection
of the compaction curve and the line S = 80% degree of
saturation. The transportable moisture limit (TML) is the critical
moisture content.
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Optimum Moisture Content (OMC) is the moisture content corresponding
to the maximum compaction (maximum dry density) under the specified
compaction condition. To check the applicability of this test, the
relationship between moisture content and dry density should be evaluated,
during this test. Then the OMC and the corresponding degree of saturation
should be determined. This test procedure was developed based on
the finding that the degree of saturation corresponding to OMC of
iron ore fines was 90 to 95%, while such degree of saturation of mineral
concentrates was 70 to 75%. In the case that the degree of saturation
corresponding to OMC is less than 90%, the shipper should consult
with an appropriate authority, for the reason that this test may not
be applicable for the material and the TML determined by this test
may be too high."
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