TABLE OF CONTENTS There are a number of different sets of National Standards in use and the major ones are the British Standards, ASTM (US), EN (Europe), and the Russian and Chinese standards. There are many common features amongst these standards many of which emanate from the British Standards that are listed below.
In order to be representative, the gross sample is compiled by collecting a number of increments spaced evenly throughout the mass of the consignment of coal and, for the specific method, BS 1017: 1989 should be consulted. The mass of an increment is determined by the maximum size of the coal shown in Table 28.1.
| Nominal upper size of coal, mm | <10 | 10 25 | 25 50 | 50 75 | 75 100 | 100 125 | 125 150 | >150 |
| Minimum size of entry into sampling implement, mm | 30 | 75 | 150 | 200 | 250 | 320 | 375 | >375 |
| Minimum mass of increment, kg | 0.5 | 1.5 | 3.0 | 4.5 | 6.0 | 8.0 | 14.0 | >14 |
The minimum number of increments required may be obtained from Table 28.2 and is determined by the class of coal and the purpose of the sample. Separate general analysis and total moisture samples may be desirable, e.g. when the coal is very wet, otherwise a common sample can be taken from which both total moisture and general analysis samples are prepared.
| Minimum number of increments to be collected from... |
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