According to the sampling representation of coal sampling device,the paper analyzed the factors influencing the sampling precisions based on GB/T 19494,such as sampler breaking and division device and sampling parameters.

The factors of influencing performance and use of crushing-dividing machine;

,indicates the classification crusher is the advanced equipment that the size of the handled material is more than the requirement,the main performances are:double functions with screening and crushing to guarantee strictly product′s granularity,the low rate of fine grain,the high handling capacity,adjustable product′s size.

By a testing machine to carry out the experiments to seperate broken mineral of coal gangue,a corresponding probability curve was obtained,and the optimization control of the coal gangue seperation was achieved by the probability value.

With available equipment,the raw material plant formulates a reasonable operating duty of crushing and screening according to the diversity of fuel categories and granularity,so that the yield of fuel granularity is stably at a higher level.

A confined compression test was used to investigate the crushing behaviors of coarse quartz sand and fine gravel particles under high compressive stress,and their fractal crushing was studied based on the fractal concept and the measured data of particle-size distribution.