Table 1 Calculation results of bottom coal thickness under different floor lithology.

From: Safety evaluation method of bottom coal thickness in thick coal seam roadway

Floor strength

σRC < σMC

σRC = σMC

σRC > σMC

Floor failure depth h3/m

0.684

0.658

0.644

Bottom coal safety thickness h4/m

1.026

0.987

0.966

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