Commercial coal samples can be taken from dynamic coal flow and static coal (including coal and coal piles carried by trains, cars, barges and ships) by mechanical method or manual method, and it is best to take them from dynamic coal flow by mechanical method.
The purpose of taking commercial coal samples is to determine the quality of commercial coal. According to the analysis and test results of commercial coal samples, we can know whether the coal shipped abroad meets the quality standards stipulated in the contract, and take this as the basis for settlement between the supply and demand sides. According to the monthly comprehensive coal samples separated from commercial coal samples, the average quality of coal transported in one month can be obtained, so as to determine the overall quality level of commercial coal.
The inspection indexes of commercial coal samples generally include moisture M, ash Ad, volatile V, calorific value Q, total moisture Mt and total sulfur S..
The gangue content of lump coal and raw coal is limited to more than 30 mm; The lower limit ratio (powder content) of screening grade coal other than final coal should also be determined.