## 3 Analysis
### Crushing Particle Size Distribution of Hard Coal
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline  & & \multicolumn{3}{c}{**Coal Particles Sieve Analysis**} & \multicolumn{3}{c}{**Curve Fitting**} & & \\ \cline{3-10}
**Specimen** & **Impact** & **Velocity** & **\(d_{\rm k}\)** & **Less than the Mass of** & **Cumulative** & **Probability** & **ln\(d_{\rm k}\)** & **lnln [1/(1 - V)]** & **CCI** & **CDI** & **Correlation Coefficient** \\
**No.** & **/(m\(\cdot\)s\({}^{-1}\))** & **/mm** & **the Grade** & **\(V/\%\)** & **ln\(d_{\rm k}\)** & **lnln [1/(1 - V)]** & **\(m_{0}\)** & **\(d_{0}\)** & **\(R^{2}\)** \\  & & & & **/g** & & & & & & \\ \hline  & & 4.75 & 8.592 & 15.335 & 1.558 & \(-1.793\) & & & & \\
1 & 2.675 & 2.36 & 3.567 & 6.366 & 0.859 & \(-2.721\) & & & & \\  & & 0.6 & 0.839 & 1.497 & \(-0.511\) & \(-4.194\) & 1.181 & 22.273 & 0.997 \\  & & 0.3 & 0.331 & 0.591 & \(-1.204\) & \(-5.129\) & & & & \\ \hline  & & 4.75 & 10.223 & 18.105 & 1.558 & \(-1.607\) & & & & \\
2 & 3.275 & 2.36 & 3.875 & 6.849 & 0.859 & \(-2.64\) & 1.457 & 14.301 & 0.999 \\  & & 0.6 & 0.58 & 1.064 & \(-0.511\) & \(-4.57\) & & & & \\  & & 0.3 & 0.195 & 0.379 & \(-1.204\) & \(-5.663\) & & & & \\ \hline  & & 4.75 & 17.821 & 31.026 & 1.558 & \(-0.967\) & & & & \\
3 & 3.574 & 2.36 & 6.399 & 11.141 & 0.859 & \(-2.116\) & 1.365 & 10.205 & 0.996 \\  & & 0.6 & 1.211 & 2.108 & \(-0.511\) & \(-3.829\) & 1.365 & 10.205 & 0.996 \\  & & 0.3 & 0.455 & 0.618 & \(-1.204\) & \(-4.815\) & & & & \\ \hline  & & 4.75 & 20.281 & 35.113 & 1.558 & \(-0.838\) & & & & \\
4 & 4.024 & 2.36 & 7.655 & 13.253 & 0.859 & \(-1.951\) & 1.287 & 9.753 & 0.995 \\  & & 0.6 & 1.604 & 2.777 & \(-0.511\) & \(-3.57\) & & & & \\  & & 0.3 & 0.661 & 1.144 & \(-1.204\) & \(-4.465\) & & & & \\ \hline  & & 4.75 & 23.12 & 38.128 & 1.558 & \(-0.819\) & & & & \\
5 & 4.804 & 2.36 & 10.173 & 16.897 & 0.859 & \(-1.768\) & & & & \\  & & 0.6 & 1.931 & 3.105 & \(-0.511\) & \(-3.499\) & 1.323 & 8.833 & 0.999 \\  & & 0.3 & 0.708 & 1.16 & \(-1.204\) & \(-4.511\) & & & & \\ \hline  & & 4.75 & 24.714 & 39.799 & 1.558 & \(-0.59\) & & & & \\
6 & 4.819 & 2.36 & 10.953 & 17.512 & 0.859 & \(-1.566\) & & & & \\  & & 0.6 & 2.013 & 3.324 & \(-0.511\) & \(-3.345\) & & & & \\  & & 0.3 & 0.752 & 1.218 & \(-1.204\) & \(-4.341\) & & & & \\ \hline  & & 4.75 & 28.488 & 48.942 & 1.558 & \(-0.397\) & & & & \\
7 & 5.011 & 2.36 & 14.314 & 24.594 & 0.859 & \(-1.265\) & & & & \\  & & 0.6 & 3.076 & 5.283 & \(-0.511\) & \(-2.914\) & & & & \\  & & 0.3 & 1.071 & 1.838 & \(-1.204\) & \(-3.986\) & & & & \\ \hline \end{tabular}
\end{table} 
Table 3: The analysis results of coal rock fragmentation. Figure 9 shows that the coal crushing degree index \(d_{0}\) reduces with the increase in velocity as a power function. This shows that the impact speed affects the fracture degree of the specimen. That is to say, the greater the impact velocity, the higher the degree of coal rock fracture. The coal crushing characteristic index \(m_{0}\) fluctuates with the increase in velocity, which is due to the dispersion of test results that are affected by the uneven internal structure of the coal specimen. Since actual coal mining needs to reduce the content of pulverized coal and increase the economic value of coal, it is necessary to ensure that the fragment size of crushed coal is not too small. The coal crushing degree index and the crushing characteristic index can be used to select the speed of coal rock impact crushing, so that the broken lump coal is controlled in a better area.