Engineering Properties of the Damuda Sandstones and Shales from the Eastern Indian Coalfields

The compressional wave velocity, compressive strength, tensile strength, permeability and density are measured for some coal-bearing rocks of Eastern India. The ranges of compressional wave velocities for the different rock types are presented. It is observed that the compressional wave velocity in sandstones increases linearly with increase of density, compressive strength, tensile strength and Young's modulus. The absorption coefficient of compressional waves in sandstones decreased linearly with increase of Young's modulus. The permeability, determined in a few sandstone samples, increased with porosity.

Empirical relations obtained by least squares technique are also presented, relating to the variation of compressional wave velocity with density, Young's modulus and the strength of sandstones. The results would find application in coal exploration and extraction.