Sigra make use of correlations between sonic logs and material properties. Full waveform tools that measure both compressive and shear waves are preferred. The analysis of these results is in terms of Young’s modulus and Poisson’s ratio and is limited to the assumption of isotropic material. The use of a rotating dipole sonic tool enables some understanding of anisotropy. As with all geophysical measurements, the sonic tool only provides a part of the picture. Extrapolation of sonic tool results to rock strength is generally dangerous.
For greater detail on Sigra’s testing capability, download the document SIGRA ROCK PROPERTY TESTING 20200604 or for a description on the use of the tests the paper by Gray (2020).