1405
1405
1405
IS : 1405- 1982
Indian Standard
METHODS OF SAMPLING IRON ORES
( Second Revision)
-
SMDC 4
Rcprcstnting
Chaiman
Indian Agrkultural
New Delhi
DR DAROGA SINCJH
Statistics
Rcscarch
Institute,
Mmbrrs
SHRI J. N. GARG ( Alternate to
D? Daroga Sirigh)
Central Statistical Organization. New Delhi
SHRI S. N. AGARWAL
Tata Iron & Steel Co-Ltd, Jakhedpur
SHRI M. G. BHADE
SHRI H. L. CHADHA ( Alternate )
The Indian Iron & Steel Co Ltd, Bumpur
DR M. M. CHAKRABORTY
Government of India Mint ( Ministry of Finance )
SHRI A. W. CXAWATHE
Directorate General of Supplies & Disponalr, N_ew
SHRI S. K. DAS
Delhi
SARI B. DASGUPTA( AIfrrnah)
Mineral Exploration Corporation Ltd, Nagpur
SHRIB. K. DHRUVA RAO
Geological Survey of India, Calcutta
SHRI D. B. GHOSH
Ferro Alloys Corporation Ltd, Shreeramnagar
SHRI C. N. HARMAN
SHRI A. SANQAME~WARA
RAO
Italab Pvt Ltd, Bombay
SHRI $ PZE~)VAR
SHEIK. P. PATEL ( Alfrmalu )
Ministry of Railways
SHRI P. K. KRISHNAMOORTEIY
SHRI R. K. DASGUPTA( Altcrnafr )
Indian Bureau of Mines, Nagpur
SHRI K. S. MAHAPATRA
SHRI U. N. SARKAR( Alternate )
Mitra S. K. Pvt Ltd, Calcutta
Smu A. K. MITRA
SHRI M. N. MITRA ( Altarnate)
Steel Authority of India Ltd, Bhilai
SHRXB. MIJKHERJEE
National Test House, Calcutta
SHRI P. K. PAIN
Indian Statistical Institute, Calcutta
SHRI R. J. PANDEY
Therapeutics
Chemical
Research
Corporation,
SHRI B. R. PATRL
Bombay
SHRI M. V. VAIDYA ( Altmatr )
Army
Statistical
Organization
(Ministry
of
SHRI T. R. PURI
Dcfence ), New Delhi
SHRI R. D. AQRAWAL( Alkrnak )
@ Copyrighr 1982
INDIAN
STANDARDS
INSTITUTION
This publication is protected under the Indian Copyright Act ( XIV of 1957 ) and
reproduction in whole or in part by any means except with written permission of the
publisher shall be deemed to be an infringement of copyright under tbe said Act
IS :1405-1982
(Confinusdfrom pug.9 1 )
Members
Represeniing
DR J. RAJARAM
SHRIV. SHANKARNARAYAN
(Alternate
I)
SHRI K.N. GuRuRAJACHAR
(AlternateII )
DR M. RAN~A RAO
Subcommittee
Members
SHRI S. K. AQRAWAL
DR S. M. RE~E ( Ahrnatc)
SHRI D. N. BHARGAVA
SHRI U. N. SARKAR ( Alternate )
SHRI S. K. DIKSHIT
SHRI A. GANCULY ( Alternate)
DIRECTOROF INDUSTRIES
& MINCE
SHRI N. B. GUDE
SHRI C. N. HARMAN
SHRI A. SANOAMESWARA
RAO
( Alternate )
SHRI S. S. HONAVAR
SHRI J. P. PATEL ( Alternate I )
SHRI J. C. DEY ( Alternate II )
DRSURESH M. JAMKHINDIKAR
SHRI D. LAHIRI
SHRI G. P. MATHUR
Mine&
Corporation
Ltd, New
( CSIR ),
SHRI A. K. MITRA
SHRI M. N. MITRA ( Altcrnafe)
Indian Aluminium Co Ltd, Calcutta
SHRI M. M. MOUDGILL
Bhilai Ispat Ltd, Bhilai
SHRI B. MUKHERJEE
SHRI PIJV~HKANTI BANERJEE
(Alternate )
( Continued on page 17 )
IS :1405-1982
Indian Standard
METHODS OF SAMPLING IRON ORES
( Second Revision )
0. FOREWORD
0.1This Indian Standard ( Second Revision ) was adopted by the Indian
Standards Institution on 25 June 1982, after the draft finalized by the
Methods of Sampling Sectional Committee had been approved by the
Structural and Metals Division Council.
0.2 This standard was originally issued in 1961 and it was subsequently
revised in 1966. Since then, a lot of developments have taken place in iron
ore industry and trade. With the increased capacity of ships, the tonnage
of a single consignment of export from Indian ports has crossed the one
lakh mark. Further handling operations have become faster thereby
necessitating speed in the operations of sampling, sample preparation,
analysis and final estimation of quality of iron ore consignments.
0.3 In the present revision, lot sizes beyond one lakh tonnes have also been
covered and the number of sub-lots into which a lot is to be divided has
been slightly reduced taking into account the need for faster sampling
operations.
Delivery of iron ore in trucks has been quite popular in some
parts of the country and to cater to this situation sampling from trucks
has also been introduced in the present revision.
0.4 Taking into consideration the latest developments in iron ore industry
and trade at national and international levels, the classification of iron ore
has been changed to include four categories, namely, lump, sized ore,
calibrated ore and fines.
0.5 The present revision mainly deals with manual sampling of iron ores
and as such cannot be employed in those cases where sampling and sample
preparation are fully mechanised.
0.6 In the formulation of this standard due consideration has been given
to international coordination among the standards and practices prevailing in different countries.
For this purpose, reference has been made
to the following documents issued by International Organization for
Standardization:
i) ISO/TC 102/SC 1 N 529E - Draft Proposal ISO/DP 3081- Iron
Ores - Increment Sampling - Manual Method.
ii) ISO/TC 102/SC 1 N 530E - Draft Proposal ISO/DP 3083 Iron
Ores - Preparation of Samples - Manual Method.
3
IS :1405-1982
0.7For the determination of size distribution of iron ores, sieves conforming to IS : 460(Part I)-1978* and IS : 460 ( Part II )-1978t, shall be used.
When such sieves are not available other
judged by the aperture size may be used.
equivalent
standard
sieves as
off,
1. SCOPE
1.1 This standard prescribes the methods for sampling of iron ores from
conveyors, wagons, trucks, ships and stock piles for the determination of
size distribution, moisture content and chemical composition of the ore in
the lot. It also lays down a method for reporting the quality of the material
sampled.
2. TERMINOLOGY
2.0 For the purpose of this standard, the following definitions shall apply.
2.3 Calibrated Ores - Ores of sizes greater than 10 mm but not exceeding
35 mm; also of sizes greater than 6 mm but not exceeding 30 mm.
2.4 Fines - Ores of sizes not exceeding 10 mm.
2.5 Lot - The quantity of ore indicated to be of the same category ( see 2.1
to 2.4) and offered for inspection at one time. A lot may consist of the
whole or a part of the quantity ordered for.
2.6 Sub-lot - The quantity of ore in each of the parts into which a lot is
divided for the purpose of sampling.
2.7 Increment - The quantity of ore obtained by a sampling device. at one
time from a lot or sub-lot.
2.8 Unit Sample - The quantity of ore collected at one point in sectional
sampling or at one time from the conveyor by stopped belt method.
*Specification for test sieves: Part I Wire cloth test sieves ( second revision ).
tSpecification
for test sieves: Part II Perforated plate test sieves (second revision).
IS : 1405- 1982
2.9 Gross Sample-
of the size
3. .GENERAL PROCEDURE
FOR SAMPLING
3.1 Sub-lots - For the purpose of sampling, a lot shall be divided into a
number of sub-lots of approximately equal mass as specified in Table 1.
NOTE -When
it is not practicable to have sub-lots of approximately
sub-lots with varying mass may also be permitted.
TABLE
NUMBER
OF SUB-LOTS
INTO
TO BE DIVIDED
(C~auses3.1,4.2,5.1,6.1,7.1
Miss OF THE LOT
(in tonnes )
5
10
15
25
35
45
60
75
100
130
160
WHICH
A LOT
MINIMUMN-RR
SUB-LOTS
2
3
4
5
6
7
8
10
001
100 000
001
130 000
001
160 000
001 adb above
12
14
16
18
to
,,
))
,)
,,
,,
,,
,,
),
,,
5
10
15
25
35
45
60
75
IS
and8.1)
000
000
000
000
000
000
000
000
up
001
001
001
001
001
001
001
equal mass,
OF
IS : 1405 - 1982
3.1.1 A representative gross sample shall be drawn from each of the sublots and shall be kept separately. Thus, there will be as many gross
samples as the number of sub-lots into which the lot has been divided.
3.2 Minimum Mass and Number of Increments - The number of increments
to be taken from a sub-lot for drawing the gross sample shall be governed
by the mass of the gross sample and the mass of increments as specified in
Table 2 for various categories of ores. This number shall be evenly distributed over the sub-lot. The increments shall be drawn with the help of a
suitable sampling scoop (see Fig. 1 ) at regular intervals.
TABLE
MINIMUM
AND
MINIMUM
( &fin )
LUMP
SIZED
800
8
100
CALIBRATED
FINES
600
400
200
75
100
50
1s : 1405- 1982
5. SAMPLING DURING LOADING OR UNLOADING
OF WAGONS
5.1 Sub-iots - For the purpose of sampling, all the wagons in a lot shall
be divided into a suitable number of sub-lots of approximately equal mass
in accordance with the requirements of Table 1.
5.1.1 A representative gross sample shall be drawn from each of the sublots and shall be kept separately. Thus, there will be as many gross
samples as the number of sub-lots into which a lot has been divided.
5.2 In order to get a representative gross sample, the ore shall be sampled
as far as possible in a steady motion during loading or unloading of the
wagons.
5.2.1 A minimum of 25 percent of the wagons shall be selected at random
from the sub-lot. The number of increments to be taken from the selected
wagons and the mass of the increments and the gross sample shall be in
accordance with Table 2. The increments shall be evenly distributed over
the selected wagons with a view to determining the necessary number of
increments that should be collected from each of the wagons of the sub-lot
for making up the gross sample. These increments shall be drawn with the
help of a suitable scoop (see Fig. 1 ) at regular intervals at the time of
loading or unloading of the wagons.
NOTE -While taking the increments as described above, if a large lump is encountered at any point and cannot be taken in the scoop, it shall be picked up as such.
The lump so obtained shall, however, be accounted for in the determination of the ore
size distribution as given under 9 and in the reduction of gross samples as given
under 10.
OF TRUCKS
6.1 Sub-lot - Quite often the nature of iron ore tendered in trucks is as
heterogeneous as that supplied in wagons or ships and variation in terms of
particle size and chemical composition has been found to be considerable
Hence, when iron ore is supwhich requires limiting of sub-lot tonnage.
plied in trucks the sub-lot size shall not exceed 100 trucks counted on
continuous basis. If loading or unloading is done shift-wise, sub-lots may
be conveniently formed in terms of trucks handled in one shift, subject to
the condition that the size of each sub-lot shall not exceed 100 trucks.
Hundred percent of the trucks are to be sampled if the ores originate
from more than one source and minimum 25 percent of the trucks in the
sub-lot are to be sampled if the ore is from a single source. The number
of increments per truck shall be adjusted SO that total number of increments
from each sub-lot ( 100 trucks or less ) is always greater than or equal to
the number specified in Table 2 for various categories of ores.
6.2 In order to get representative sample, increments shall be drawn at the
time of loading or unloading of the trucks. From each truck in the sub-lot,
7
Is : 1405 - 198a
a minimum of one increment shall be drawn. For drawing increments 8 kg
or 4 kg sampling scoop ( Fig. 1) shall be used depending on the category of
ore. At the time of taking increments care shall be taken not to exclude
deliberately lumps or fines and this will be ensured by drawing increments
in the middle of loading/unloading time of a truck.
6.3 The aggregate of increments collected from each sub-lot shall constitute
a gross sample.
7. SAMPLING FROM SHIPS DURING LOADING/UNLOADING
7.1 For the purpose of sampling the quantity
7.2 In order to get a representative gross sample, ore shall be sampled as far
as possible when in motion. If it is taken on a conveyor, the gross sample
shall be collected according to the procedure laid down in 4. If the ore is
handled in any other manner the gross samples may be drawn during loading
or unloading of the ship. For this purpose, the number of increments to
be taken at regular intervals and the mass of the increments and the gross
sample shall be in accordance with Table 2 for different categories of ore
( see also Note under 5.2.1).
7.3 The aggregate of the material collected from the various increments or
unit samples from a sub-lot shall constitute a gross sample.
8. SAMPLING FROM STOCKPILES
8.1 Sub-Lots -
8.a Sampling of ore from stockpiles shall be carried out, as far as possible,
when ore is in motion, that is, during the making or breaking of the
stockpiles.
8.a.l The number of increments to be taken from a sub-lot for making up
the gross sample, shall be governed by the mass of the gross sample and
the mass of the increments as specified in Table 2 for various categories of
iron ore. This number shall be equally distributed over the sub-lot. The
IS : 1405- 1982
increment shall be drawn with the help of a suitable sampling scoop ( see
Fig. 1) at regular intervals in the course of making or unmaking of the
stockpiles (see also Note under 5.21).
8.3 When it becomes necessary to sample a stationary stockpile sectional
sampling method ( see 8.3.1) or trench sampling method (see 8.3.2 ) may
be used for a stockpiles up to a maximum height l-5 metre only. In the
former case, the requisite number of points shall be located at random on
the entire surface of the sub-lots.
8.3.1 Sectional Sampling - By this method, at least 4 unit samples in the
case of fine and calibrated ores and at least 8 unit samples in the case of
sized ore and lumps are to be collected from each sub-lot. For this purpose, the requisite number of points shall be chosen at random on the entire
surface of the stockpiles. At each of the selected points, a circle of suitable diameter (minimum three times the largest particle size ) shall be
marked. The material over the area of this circle and along entire height
of the stockpile from top to bottom shall be collected in stages. This can
be done by taking initially ores up to a depth of 50 cm and covering the
hole so formed by a plate for removing the ores lying on the sides of
the hole. Then after removing the plate further depth can be reached in
the same manner and the ores can be collected from the freshly formed
hole.
8.3.2 Trench Sampling -The
gross sample shall be made up of the
number of increments as specified in Table 2. These increments shall be
collected as indicated in 8.3.2.1.
8.3.2.1 Along a randomly chosen line on the ore surface of the sub-lot,
a trench shall be dug, right down to the ground level leaving about O-3 m
walking space at the ground level. From the trenches so dug, the required
number of increment shall be collected with the help of suitable sampling
scoop, at various points randomly spread over the two exposed sides of the
trenches. In case of large stockpiles, in addition to the trench, the sides
of the piles may also be opened to expose the ore down to the bottom, at
places where the trench does not expose the ore inside.
9. DETERMINATION
OF SIZE DISTRIBUTION
9.1 The size distribution of iron ores in a lot shall be estimated as per
contract.
In the determination of ore size distribution, IS sieves of suitable
sizes specified in IS : 460 ( Part I )* and IS : 460 ( Part II)? shall be used.
9.2 Gross Samples Obtained from Aggregating Unit Samples
9.2.1 Each gross sample shall be screened through selected IS sieves and
the ore retained on each of the sieves and that passing through the
*Specihation
tSpecification
10
IS : 1405- 1982
of the lot
a, + as + -*-.** x. 100
Wl + wg + . . . . . .
where
WI, w2, ...... are the mass of the different gross samples; and
a,, a2 . . . . . ., are the corresponding masses of ore in the size
range A ( A may be below, above or bounded by
two nominal sizes of IS sieves ).
9.3 Gross Samples Obtained by Aggregating Increments
9.3.1 Where gross samples do not contain any lumps, the procedure
detailed in 9.2 shall be followed for estimating the ore size distribution in
the lot, the percentage of ore. over 150 mm being nil.
9.3.2 Where the gross samples contain some lumps (see Note under
5.2.1) the portion of the gross samples excluding the lumps shall be treated
as in 9.2.1.
9.3.2.1 The ore size distribution of the lot shall be estimated as
follows:
nx8
a) Over 150 mm, percent =
(n x 8) i- ~1 + w2 + wQ+ . . . . . .
b, + b, + . . . . . . ._I. . .
b) Any other size fraction B = (n x 8 ) + w, + w, + We. . . . . .
where
w* WI . . . . . . are the mass of the different gross sample
excluding the lumps,
n is the total number of lumps in all the gross samples, and
bl, b, . . . . . . are the mass of ores in the size range B in different
gross samples.
NOTF -For lump and sized ores, each lump picked up in the course of sampling is
supposed to represent one increment of 8 kg.
IS : 1405 - 1982
and fine
Gross Sample
Size determination
Crushed tt - 10 mm
4
Mixing and reduction to 50 kg
4
J25 kg of reduced sample
J
Crushed to pass through 475 mm IS Sieve
4
Mixing and reduction to 12.5 kg
+
Crushed to pass through 335 mm IS Sieve
Mixing and reductionto
4
Crushed to pass through
JMixing and reduction to
4
CrUISSheSd;;;epassthrough
850 micron
1.6 kg
6.2 kg
1.70 mm IS Sieve
3.1 kg
150 micron
4
25 kg reduced sample
4
Duplicate moisture
samples of 1 kg each by
increment reduction
STAGES
analysis )
IN REDUCING
A GROSS
SAMPLE
12
IS : 1405 i 1982
methods detailed in 10.2.1 to 10.2.3 shall be followed. Each of the
moisture samples shall weigh minimum 1 kg and laboratory
sample
minimum 150 g.
10.2.1 Reduction by R@e Divider - After each crushing the ore shall be
well mixed and poured into the riffle. This process shall be repeated using
different sizes of riffles according to the size of the crushed ore.
10.2.2 Coning and Quartering Method- The crushed ore shall be well
mixed and then scooped into a cone-shaped pile. Care shall be taken to
drop each scoopful exactly over the same spot as otherwise the central axis
of the cone will be slackened and an uneven distribution of lumps and fines
will result. After the cone is formed, it shall be flattened by pressing the
top of the cone with the smooth surface of the scoop. Then it is cut into
quarters by two lines which interesect at right angles at the centre of the
cone. The bulk of the sample is reduced by rejecting any two diagonally
opposite quarters.
10.2.3 Increment Reduction Method -The
crushed ore shall be spread
on a smooth non-moisture absorbing plate into a uniform flat rectangle
with the thickness specified in Table 3. The rectangle so formed shall be
divided into 5 equal parts lengthwise and 4 equal parts breadthwise.
From
each of the 20 parts so obtained, equal quantities of ore shall be collected
by the use of suitable scoop once or more number of times depending on
the quantity of divided sample.
10.2.3.1 The method of increment reduction is recommended only
when the division ratio is high. As such, in the illustration given in Fig. 2,
this method can be applied in the initial stage when the gross sample is
reduced to 50 kg, and also at the final stage for obtaining laboratory
samples. For obtaining duplicate moisture sample also, increment reduction method is preferred to other methods. Table 3 gives the thickness of
layer of ores and the minimum mass of increment from each rectangular
part, to be taken at one time with the use of suitable sampling scoop.
10.3 Laboratory Samples - The laboratory samples shall be obtained after
the material is pulverized to pass through 150-micron IS Sieve. The
material so obtained shall be divided into three or more equal parts, as
requested by the purchaser, the supplier, the referee and others, if any. All
the laboratory samples shall be preserved in dry, clean and well stoppered
containers and labelled with full identification particulars like, source of
the ore, category of the ore, suppliers name, the lot and sub-lot number
and date of sampling.
11. NUMBER OF TESTS
11.1 Moisture Sample- All the moisture samples representing a lot
shall be tested individually for moisture content. Duplicate moisture
13
ls : 1405- 1982
TABLE 3
MAXIMUM SIZE
OF ORE
APPROXIMATE
QUANTITY
TO BE OBTAINED PROY EACH
PART AT Om TIME
(2)
(1)
mm
30 to
25 to
20 to
15 to
10 to
5 to
mm
10
4-75
3.35
l-70
O-85
o-15
(3)
S
250
150
40
35
30
25
20
10
z
25
5
determinations shall be made for each sub-lot. To avoid any change in the
moisture content, the moisture determination shall be done as quickly as
possible, after the sample is taken.
11.2 Sub-lot Laboratory Samples - All the sub-lot laboratory samples shall
be tested individually for important chemical characteristics.
For testing
the remaining characteristics, a composite sample as prescribed in 2.13
shall be prepared and analysed. The following scheme is recommended for
carrying out chemical tests of iron ore:
Chemical Constituents of the Ore for Which
Sub-lot samples are analysed
individually
Fe content and any other
chemical characteristic which is
important or found variable
A composite sample is
analysed
All the radicals stipulated
in the contract
12. REPORTING
12.1 Reporting of Chemical Composition
12.1.1 For those characteristics, where a composite sample has been
tested, only one test result will be available and that result shall be reported
as the value of the characteristic for the lot sampled.
12.1.2 When only two laboratory samples have been analysed individually
from a lot, the average of the two available test results shall be reported as
the value of the characteristic for the lot sampled. In the case of sub-lots
of approximately equal mass, this average shall be calculated as one half of
the sum of the two test results. If the sub-lots are of varying mass, then
the weighed average shall be calculated as the sum of each test result
multiplied by corresponding fraction got on dividing the sub-lot weight by
14
IS : 1405 - 1982
the total weight. The individual results shall also be reported to given an
indication of the range of variation in quality.
12.1.3 When three or more laboratory samples have been analysed
individually from a lot for any characteristic, the following procedure shall
be followed to assess the average quality and its limits of variation:
Let x1, x2, x8... . . . . . . . . . . . . . . .xn be the results of analysing n laboratory
samples for a particular characteristic.
Calculate:
Average(z)=
X1+
. . .. .. ... .. .
or Weighted
wrxr + . . . . . . . . . wnxn
where wl, IV*,. . . . . . . . . w,, are
WI + ---*-****-****WI1 mass of the sub-lots.
Range ( R) = the difference between the maximum and the
minimum of the values ( when n is less than 10 )
or
( x) = the average value of ranges. When the number of
sub-lots n is equal to 10 or more, the corresponding
results on laboratory samples ( 10 or more) should
be constituted into two groups in the order of their
occurrence.
For each group, range ( R ) should be
calculated and the average value ( K) of the Rs
should be used in the subsequent clause.
The average level of the characteristic in the lot shall be reported as equal
to (z).
average
( K) =
The limits of variation in the average level of the lot shall be reported
as (I? f hR) or ( P f hE), where h is a factor, the value of which depends
on the number of samples analysed. The appropriate value of the factor h
shall be taken from the following table:
No. of Laboratory
Value of the
Samples AnaIysed
Factor h
3
4
I.30
O-72
o-51
o-40
0.33
0.29
o-31
0.25
o-21
o-19
0.17
z
7
1:
12
14
ii
15
IS :1405-1982
where
16
Is :1405-198t
( fhtinwd from page 23
Rtprwntinp
Mmb#rs
Export Inspection
SBRI R. C. PALHAN
SHRI KARAM
CHAND
SHRX B. R. PATEL
( Altcmak )
SHRIG.V.
of India, Calcutta
(Alternate)
Council
SUEIRAMAHYA~
Therapeutics
Bombay
Chemical
Research
Corporation,
Testing
National
Mineral
Hyderabad
Goa ( gEaral
17
Ore
Co
Develop*ment
Exporters
( India)
Pvt
Corporation
Association,
Ltd,
Ltd,
Panjim