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1、BRITISH STANDARD BS ISO 3086:1998 Iron ores Experimental methods for checking the bias of sampling ICS 73.060.10 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 3086:1998 This British Standard, having been prepared under the direction
2、 of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 June 1998 BSI 04-1999 ISBN 0 580 29958 9 National foreword This British Standard reproduces verbatim ISO 3086:1998 and implements it as the UK national standard. The UK participatio
3、n in its preparation was entrusted to Technical Committee ISE/58, Iron ores, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests info
4、rmed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in
5、 this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract.
6、Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, p
7、ages 1 to 9 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Mo
8、n Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 3086:1998 BSI 04-1999i Contents Page National forewordInside front cover Forewordiii Text of ISO 30861 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy
9、: sheffieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 3086:1998 ii BSI 04-1999 Contents Page Forewordiii 1Scope1 2Normative references1 3Definitio
10、ns1 4Principle1 5General conditions1 6Sampling and sample preparation methods1 6.1Sampling1 6.2Sample preparation2 7Analysis of experimental data2 7.1Determination of the standard deviation of the differences2 7.2Determination of the confidence interval for 2 7.3Statistical analysis3 8Test report3 A
11、nnex A (normative) Flow sheet of the statistical analysis4 Annex B (informative) Numerical examples of experiments4 Table 1 Value of t at 10 % level of significance (two-sided test)2 Table B.1 Experimental data5 Table B.2 Experimental data6 Table B.3 Experimental data7 Table B.4 Experimental data8 D
12、escriptors: Minerals and ores, metalliferous minerals, iron ores, sampling, error checking, bias. d Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 3086:1998 BSI 04-1999iii Foreword ISO (the International Organization for Standardizat
13、ion) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be r
14、epresented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Sta
15、ndards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 3086 was prepared by Technical Committee ISO/TC 102, Iron ores, Subco
16、mmittee SC 1, Sampling. This third edition cancels and replaces the second edition (ISO 3086:1986), which has been technically revised. Annex A forms an integral part of this International Standard. Annex B is for information only. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+
17、00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 3086:1998 BSI 04-19991 1 Scope This International Standard specifies experimental methods for checking the bias of the sampling of iron or
18、es, when the sampling is carried out in accordance with the methods specified in ISO 3081 or ISO 3082, having as reference a stopped-belt sampling method according to ISO 3081. NOTE 1Sampling systems not completely in accordance with ISO 3081 or ISO 3082 are not always expected to be biased. Therefo
19、re bias checking may be done when there is some disagreement about the importance of some departure from the conditions of ISO 3081 and ISO 3082. If one party argues that the bias is likely to be substantial under some particular set of conditions then bias testing should mostly be done when those c
20、onditions apply. NOTE 2The method for analysis of experimental data described here may also be applied: a) for checking the bias of sample preparation of iron ores, having as reference the methods for sampling preparation according to ISO 3082 and ISO 3083; b) for checking a possibly significant dif
21、ference in the results obtained from the samples of one lot collected at different places, for example, a loading point and unloading point. 2 Normative references The following Standards contain provisions which, through reference in the text, constitute provisions of this International Standard. A
22、t the time of publication, the editions indicated were valid. All Standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the Standards indicated below. Members of IEC and
23、ISO maintain registers of currently valid International Standards. ISO 3081:1986, Iron ores Increment sampling Manual method1). ISO 3082:1987, Iron ores Increment sampling and sample preparation Mechanical method1). ISO 3083:1986, Iron ores Preparation of samples Manual method1). ISO 3085:1996, Iron
24、 ores Experimental methods for checking the precision of sampling. ISO 11323:1996, Iron ores Vocabulary. 3 Definitions For the purposes of this International Standard, the definitions given in ISO 11323 apply. 4 Principle The results obtained from the method to be checked (referred to as method B) a
25、re compared with the results of a reference method (referred to as method A) which is considered to produce practically unbiased results, from technical and empirical viewpoints. In the event of there being no significant difference, in a statistical sense, between the results obtained by method B a
26、nd method A, method B may be adopted as a routine method. This difference is assessed by comparing a 90 % confidence interval for the true average bias with the relevant bias, (see 5.2). 5 General conditions 5.1 The number of lots to be tested shall be not less than ten. The number of further tests
27、required depends on the confidence interval for the true average bias, based on at least ten tests, and the value of the relevant bias, . 5.2 The relevant bias, , which is considered large enough to justify the likely expense of reducing the average bias, shall be decided beforehand. As a guide, is
28、likely to be less than BSPM, the standard deviation for sampling, sample preparation and measurement, determined according to ISO 3085. NOTEIf the experiment is aimed at checking the sample preparation only, the value of is likely to be less than BPM, determined according to ISO 3085. 5.3 Quality ch
29、aracteristics such as total iron content, moisture content, size distribution and physical properties may be used. 6 Sampling and sample preparation methods 6.1 Sampling The reference method, method A, for checking the bias of sampling is a stopped-belt sampling method according to ISO 3081. Method
30、A: take each increment from the full width and thickness of the ore stream on the stopped conveyor at a specified place for a length of belt more than three times the nominal top size or 30 mm, whichever is the greater. The method to be checked, method B, carried out according to ISO 3081 or ISO 308
31、2, shall be compared with method A for the same material. Method B: sampling methods such as sampling from moving conveyors with a mechanical sampler and sampling during the transfer to or from ships and wagons are examples of method B. 1) To be revised and published as ISO 3082 Licensed Copy: sheff
32、ieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 3086:1998 2 BSI 04-1999 6.2 Sample preparation Methods for making up a pair of gross samples, preparation of samples and testing shall be as given in 6.2.1 to 6.2.3. 6.2.1 Increments obtained from one lot,
33、in accordance with method A and method B, are made up into two gross samples, A and B. 6.2.2 The gross samples, A and B, are subjected, in the same manner, to sample preparation as specified in ISO 3082 or ISO 3083 and tested as specified in the relevant International Standards separately, and a pai
34、r of measurements obtained. 6.2.3 The above procedure is performed on ten or more lots (see 5.1). NOTE 1When increments for method A and method B can be taken from closely adjacent portions of the ore, it is recommended that sample preparation and testing be carried out on individual increments or o
35、n combinations of a small number of adjacent increments. This allows comparisons of ten or more pairs of measurements to be made more quickly than if measurements were only made on entire lots. The above comparison of measurements should be made on pairs of increments taken from several lots, prefer
36、ably of the same type of ore. However, it is not permitted to combine a number of paired results, originating from both increments and gross samples. It should be either a number of pairs from increments or ones from gross samples. NOTE 2Given the cost and inconvenience of stopped-belt sampling, it
37、is generally economic to conduct sample preparation and testing in duplicate and with great care so that the number of stopped-belt samples might be reduced. 7 Analysis of experimental data 7.1 Determination of the standard deviation of the differences 7.1.1 Denote individual measurements obtained i
38、n accordance with method A and method B, xAi and xBi, respectively. 7.1.2 Calculate the difference, di, between xAi and xBi using the equation: where k is the number of paired sets of measurements. 7.1.3 Calculate the mean, , of the differences to one decimal place greater precision than that used i
39、n the measurements themselves: 7.1.4 Calculate the sum of squares, SSd, and the standard deviation, sd, of the differences: 7.2 Determination of the confidence interval for 7.2.1 1 Denote the lower limit of the confidence interval LL and the upper limit of the confidence interval UL. 7.2.2 Calculate
40、 the limits of the confidence interval using the equations: Where t is the value of Students t distribution for (k 1) degrees of freedom and is given in Table 1. Table 1 Value of t at 10 % level of significance (two-sided test) NOTETable 1 is taken from ISO 2602:1995, Statistical interpretation of t
41、est results Estimation of the mean Confidence interval. Tables of t are available in large numbers of statistical text books. Where the number of paired sets of measurements is k, the t value for (k 1) degrees of freedom is used. (1) (2) .(3) (4) d (5) (6) Number of paired sets of measurements, t Nu
42、mber of paired sets of measurements, t kk 101,833261,708 111,812271,706 121,796281,703 131,782291,701 141,771301,699 151,761311,697 161,753321,696 171,746331,694 181,740341,692 191,734351,691 201,729401,685 211,725501,677 221,721811,664 231,7171211,658 241,7142411,651 251,711Z1,645 d Licensed Copy:
43、sheffieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 3086:1998 BSI 04-19993 7.3 Statistical analysis Plot on a horizontal scale, with 0 (zero) in the centre, the values of LL, UL, + and . Check if the interval between LL and UL is entirely contained in t
44、he interval between and + . If this happens, any bias is not large enough to justify the likely expense of reducing it. Stop the test and conclude that method B may be adopted as a routine method. If this does not happen, check if the interval between LL and UL includes the 0. If 0 is not included i
45、n this interval, then conclude that method B cannot be adopted as a routine method and the sampling system shall be adjusted. If 0 is included in this interval, then more sampling and testing are necessary. After each new pair of results, or, if desired, several new pairs of results to reduce mobili
46、zation costs, repeat the procedure from 7.1 to 7.3 until the test conclusion on acceptance or rejection of the routine method is definite. (See Annex A). 8 Test report The test report shall include the following information: a) names of supervisor and personnel who performed the experiment; b) site
47、of experiment; c) date of issue of the test report; d) period of experiment; e) characteristic measured and reference to International Standard(s) used; f) details of the lots investigated; g) details of sampling and sample preparation; h) t value and conclusion; i) comments and remarks by the super
48、visor; j) action taken based on the results. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 06:01:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 3086:1998 4 BSI 04-1999 Annex A (normative) Flow sheet of the statistical analysis Annex B (informative) Numerical examples of experiments Th
49、e experimental data shown in Table B.1 to Table B.4 were obtained from real experiments, which have been altered by adding a constant to the results obtained by both methods (A and B) to protect the source of the data. However the conditions of the experiments and the values of the relevant bias are examples only. B.1 Numerical example 1 (: 0,10 % total iron content) The numerical example shown in Table B.1 is the result of an experiment comparing mechanical sampling (method B) with the reference method A. The