8541 International Standard (ISO Manganese and chromium ores - Experimental methods for checking the bias of sampling and sample preparation Minerais de manganese et de chrome - Methodes experimentales de controle de I'erreur systématique d'echantillonnage et de preparation des échantillons First edition - 1986-10-15 UDC 553.32 + 553.461 : 620.113 [SO 8541-1986 (E) Ref. No. ISO 8541-1986 (E) Descriptors: minerals and ores, manganese ores, , chromate minerals, quality audit, statistical quality control, sampling, rules of calculation. Price based on 6 pages Copyright International Organization for Standardization Not for Resale Foreword ISo (the International Organization for Standardization) is a woridwide 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 mental and non-governmental, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the Iso Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 8541 was prepared by Technica! Committee ISO/TC 65, Manganese and chromium ores. Users should note that all International Standards undergo revision from time to time and that any reference miade herein to any other International Standard implies its latest edition, unless otherwise stated. @ International Organization for Standardization, 1986 Printed in Switzerland Not for Resale INTERNATIONAL STANDARD ISO8541-1986 (E) Manganese and chromium ores - [ Experimental methods for checking the bias of sampling and sample preparation 1 Scope and field of application assured if the two samples taken by method A and method B are from identical material and undergo identical processing This International Standard specifies experimental methods for and analysis almost simultaneously under similar conditions. checking the bias of sampling and preparation of samples of manganese and chromium ores, whether natural or processed, when the sampling is carried out in accordance with the 3.6 In cases where the pairing of individual increments of a methods specified in the relevant International Standards. sample taken by method A and that by method B is considered to be not sufficient, the method of data analysis for unpaired data shall be applied. References 2 The method of unpaired data analysis used in this International Standard is based on the condition that the numbers of Sampling ISO4296/1, Manganese ores Part 1: measurements of method A and method B are the same. Care Increment sampling. shall be taken to obtain the same number of increments of a sample for both methods. Sampling ISO'4296/2, Part 2: Manganese ores Preparation of samples. Experimental methods 4. General conditions Experiments for bias of sampling 4.1 3.1 The sampling and preparation of samples shall be carried out in accordance with the methods specified in the relevant International Standards. 4.1.1 Methods'to be checked Examples of checking the bias of methods of sampling are 3.2 In the experimental method, the results obtained from given in 4.1.1.1 to 4.1.1.5. the method to be checked (referred to as method B) shall be compared with the results of a specified reference method (referred to as method A) which is assumed to produce prac 4.1.1.1 Sampling from conveyors tically unbiased results from technical and empirical view- points. The comparison shall be made by use of a statistical Method A: Stopped-belt sampling shall be the reference method of test for significance of difference between two mean method in which each increment is taken from a stopped-belt values of test results at the 5 % level of si