ABSTRACT
Strength of Point – Load >10 MPa intact 4-10 2-4 1-2 For this low range – UCS rock strength preferred
index, MPa Uniaxial >250 MPa 100-250 50-100 25-50 5-25 1-5 <1 compressive strength (UCS), MPa Rating 15 10 7 4 2 1 0
Drill core quality RQD, % 90-100 75-90 50-75 25-50 <25 Rating 20 17 13 8 3
• The discontinuity rating shows it to be the most more important parameter in evaluating the rock rating.
