Explain the objective of rock mass classification schemes, RMR and Q, why RQD is important to such schemes, what the main components are and what the main differences are. In a run of 1.5 m of NQ core (4.75 cm diameter), fractures are observed at 8.4, 18.3, 33.5, 39.9, 66.8, 77.0, 90.7, 95.5, 110.5, 134.1 and 137.7 cm measured along the core from one end to the other. Find the RQD. Explain.