The RMi (rock mass index) system is based  on well defined inherent rock mass parameters.  Basically,  it combines the compressive strength of intact rock and a jointing  parameter composed of 4 jointing characteristics, namely block volume or densþ of joints, joint roughness, joint alteration,  andjoint  size. From calibration  of measured  compressive strength of 7 large samples and 1 back analysis, the 4 jointing features have been combined to express the effect the jointing  parameter has in reducing the strength  of intact rock.