Fig. 1. Dust-near infrared spectroscopy experimental device

Fig. 2. Spectra of 23 coal and rock samples
(a): 11 typical coal measures samples(b): 12 typical coal samples

Fig. 3. Near-infrared spectroscopy of different dust concentrations in typical coal samples
(a): Sample 2, anthracite No.2;(b): Sample 10, gas coal;(c): Sample 12, lignite coal

Fig. 4. Near-infrared spectra of different dust concentrations in typical rock samples
(a): Sample 17, sandy shale No.2;(b): Sample 20, siltstone No.1;(c): Sample 23, argillaceous limestone No.2

Fig. 5. Angle cosine between experimental samples and standard samples

Fig. 6. Correlation between experimental samples and standard samples

Fig. 7. Processed standard spectral database by SG+SNV
(a): Typical coal measures samples;(b): Typical coal samples

Fig. 8. Angle cosine between experiment samples and standard samples

Fig. 9. Correlation coefficient between experimental samples and standard samples

Fig. 10. Coal and rock identification results of experimental samples by two recognition models
(a): Spectral angle matching (SAM);(b): Pearson correlation coefficient