AS 3880:2017 pdf free.Flow properties of coal.
2.2 SA1PLE PRFPARATION
2.2.1 Sample top size
Flow property measurements are carried out on the natural minus 4 mm fraction of a representative sample of the material to be handled. After drying, the sample shall be sieved according to the method set out in AS 3881 to separate the minus 4 mm fraction from larger material. All tests shall be carried out on the minus 4 mm material occurring naturally in the sample. Care shall be taken at all stages of sampling, sample handling and testing to prevent undue breakage into fine particles.
NOTE: Because testing of flow properties is carried out in small sized apparatus, only the finer fraction of the coal can be tested. Since, however, it is the lines that show the poorest flow characteristics, the results are somewhat conservative on average but reflect the worst case conditions likely to be met in practice. It is important to note that the flow of a material with a large fraction of fines is governed by the properties of the fines.
2.2.2 Sample size
The sample for testing shall be prepared by the methods given in the ISO 13909 series. Sufficient sample shall be taken to yield 1 kg of minus 4 mm material after screening. If. however, time-delayed tests are also to be carried out, sufficient sample to yield 5 kg of minus 4 mm material is required.
2.2.3 Sample division
When necessary, the sample shall be divided by riffling or mechanical sample division to provide the required quantity for analysis. Dust loss and size degradation shall be minimized.
2.2.4 Moisture content
The test sample shall be at the nominated moisture level. The moisture content of the full size bulk sample and minus 4 mm test sample shall he measured before and after flow property testing, in accordance with AS 1038.1, and should not vary by more than 0.5% on a mass basis. Samples shall be stored in sealed containers or similar to maintain moisture content. The moisture content of the minus 4 mm in relation to the full size sample shall be determined and recorded on the results sheet (see Clause 4.9).
NOTES:
I For design purpose. the sample should be in that state that reflects its condition during handling. Thus, the sample should be adjusted if needed, for instance by increasing or decreasing its moisture content. When design is to be realized for the most difficult flow conditions, it is recommended to determine the ‘worst case moisture content’, i.e. the moisture content leading to the worst flow properties. A method to determine the ‘worst case condition’ based on drained saturated moisture is given in Appendix B.
2 While the flow property results are based on the minus 4 mm size fraction, to be meaningful, the results need to be applied to the actual full size variation of the coal being handled.AS 3880 pdf download.