Page 192 - Advances In Productive, Safe, and Responsible Coal Mining

Out-of-seam dilution: Economic impacts and control strategies 171

4.00
3.00 Roof level
Coal-roof interface
2.00
1.00
Coal
0.00
Feet Pre-Ed Pillar 1 Pillar 2 Pillar 3 Pillar 4
–1.00

–2.00
Coal-floor interface
–3.00

Floor level
–4.00
–5.00
Fig. 9.5 Variation in mining height and OSD extraction from just before OSD awareness
training through 2weeks following the training [17].

Analysis of pre- and post-EAP data (see Fig. 9.6) revealed a definite relationship
between OSD thickness and coal seam thickness. OSD is observed to increase with
decreasing seam height. The relationship is described by the linear regression equation
as follows:

OSD thickness ¼ 0:8331 seam thickness + 5:4945 (9.2)

2.0

1.6
y = –0.8331x+5.4945

1.2
OSD (ft)

0.8

0.4

0.0
4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
Seam height (ft)

Fig. 9.6 Regression analysis showing relationship between OSD thickness and seam height [17].