Reduction of coal samples to 60 mesh is an important and necessary step for all subsequent coal analysis methods. Section 220.127.116.11 requires all samples to be passed through a 60 mesh screen after pulverization, and any oversized particles shall be reduced on a buckboard and added to the sample mass. Some labs have prepared technical justifications for skipping this step on higher-ranked coals with no perceived bias. But on lower-ranked coals, passing every sample through a 60 mesh sieve and reducing oversize particleshas been shown to cause statistically significant moisture and heating value bias. After discussion, the task group decided to remove the next-to-last sentence in Section 18.104.22.168 This action would eliminate the requirement to pass every sample through a 60 mesh sieve.
Keywordscoal; composite; division; reduction;;
Draft Under Development