Determination of sampling precisionSampling precision is determined according to the purpose of sampling, the type of sample and the requirements of the parties to the contract. In the absence of protocol precision, refer to Table 1 to determine
Table 1 Total precision of coal mining, production and chemical
|Coal varieties||Precision Ad /%|
|Clean coal||± 0.8|
|Other coal||± 1 / 10Ad, but ≤1.6%|
When the required precision is changed, the number of sampling units and the number of words per sampling unit shall be changed as described in 5.2.4, and the required precision shall be re-checked; when it is suspected that the variability of the coal is increased Also check the sampling precision.