9
fines generation, with shallow cuts at 0.2-inch penetra-
tion generating the most amount of fines (456.01g), while
medium depth cuts at 0.4-inch (438.8g) and deep cuts at
0.5-inch (269.6g) are the deepest. Bit wear, on the other
hand, is linearly correlated with fines generation: it pro-
gresses from new bits (369.24g) to moderately worn bits
(517.6g) and reaches its peak at fully worn bits (627.73g).
That’s a 70% jump in fines production between new and
worn states. This correlation implies that at deeper depth,
the pick might consume more energy, but produce less fine
particles, and bit wear is more effective in increasing fines
production irrespective of penetration depth.
Laser Diffraction-Smaller Fines
The fine size distributions for the three pick wear condi-
tions are presented in Figure 2. During data collection, the
equipment detected a range of particle sizes while recording
the raw physical diameters. The particle size bins, measured
in micrometers (µm), used for data collection in the “per-
cent channel” covered a broad range of airborne particles.
These bins were designed to offer the best possible balance
between processing speed and resolution, ensuring a reli-
able particle size distribution while maintaining efficiency
in data processing.
The PSD was obtained from laser diffraction with a
minimum size of 2000 microns. The bin size for the par-
ticle ranges from 88 µm for new, 148 µm for moderately
worn- out, and 248.9 µm for completely worn-out bits
10
53
37
23 8 9 4 4 1 3 4
0
20
40
60
80
100
120
140
160
180
Particle size (mm)
cumulative cumulative %
10
53
37
23
8 9 4 4 1 3 4
Particle size (mm)
Figure 14. Particle size distribution of 0.5 penetration
Table 4. Particle size distribution (count and cumulative) of different penetration
0.2 0.4 0.5
Particle Size Count Cumulative Count Cumulative Count Cumulative
0–100 0 0 4 4 10 10
100–200 5 5 40 44 53 63
200–300 22 27 34 78 37 100
300–400 17 44 6 84 23 123
400–500 6 50 13 97 8 131
500–600 4 54 4 101 9 140
600–700 4 58 2 103 4 144
700–800 3 61 1 104 4 148
800–900 0 61 2 106 1 149
900–1000 0 61 1 107 3 152
1000 2 63 1 108 4 156
Figure 15. (left) Particle Shape of Worn Pick (center)
Particle Shape of Mod Pick (right) Particle Shape of New
Pick
Cumulative
%
Particle
number
fines generation, with shallow cuts at 0.2-inch penetra-
tion generating the most amount of fines (456.01g), while
medium depth cuts at 0.4-inch (438.8g) and deep cuts at
0.5-inch (269.6g) are the deepest. Bit wear, on the other
hand, is linearly correlated with fines generation: it pro-
gresses from new bits (369.24g) to moderately worn bits
(517.6g) and reaches its peak at fully worn bits (627.73g).
That’s a 70% jump in fines production between new and
worn states. This correlation implies that at deeper depth,
the pick might consume more energy, but produce less fine
particles, and bit wear is more effective in increasing fines
production irrespective of penetration depth.
Laser Diffraction-Smaller Fines
The fine size distributions for the three pick wear condi-
tions are presented in Figure 2. During data collection, the
equipment detected a range of particle sizes while recording
the raw physical diameters. The particle size bins, measured
in micrometers (µm), used for data collection in the “per-
cent channel” covered a broad range of airborne particles.
These bins were designed to offer the best possible balance
between processing speed and resolution, ensuring a reli-
able particle size distribution while maintaining efficiency
in data processing.
The PSD was obtained from laser diffraction with a
minimum size of 2000 microns. The bin size for the par-
ticle ranges from 88 µm for new, 148 µm for moderately
worn- out, and 248.9 µm for completely worn-out bits
10
53
37
23 8 9 4 4 1 3 4
0
20
40
60
80
100
120
140
160
180
Particle size (mm)
cumulative cumulative %
10
53
37
23
8 9 4 4 1 3 4
Particle size (mm)
Figure 14. Particle size distribution of 0.5 penetration
Table 4. Particle size distribution (count and cumulative) of different penetration
0.2 0.4 0.5
Particle Size Count Cumulative Count Cumulative Count Cumulative
0–100 0 0 4 4 10 10
100–200 5 5 40 44 53 63
200–300 22 27 34 78 37 100
300–400 17 44 6 84 23 123
400–500 6 50 13 97 8 131
500–600 4 54 4 101 9 140
600–700 4 58 2 103 4 144
700–800 3 61 1 104 4 148
800–900 0 61 2 106 1 149
900–1000 0 61 1 107 3 152
1000 2 63 1 108 4 156
Figure 15. (left) Particle Shape of Worn Pick (center)
Particle Shape of Mod Pick (right) Particle Shape of New
Pick
Cumulative
%
Particle
number