1548 Table 2 – Cuttability index and roadheader performance predictive models Bilgin et.al. (1988), ICR = 0.28×P×0.974 hwxy where, RMCI = rockmass cuttability index (kg/cm2) RQD = rock quality designation (%) σc = unconfined compressive strength (kg/cm2). P = Motor Power, HP, ICR = Instantaneous cutting rate (bcm/h) Gehring (1989) For Roadheader model VASM-2D; where, L* = production or cutting performance (bcm/h) N = cutter head power (kW) k = a factor for consideration of relative cuttability or tuning effect between road header and rock σc = unconfined compressive strength (MPa). k1 = relative cuttability of intact rock and, = 6 for very tough and plastic rock = 7 for tough and plastic rock = 8 for average rock = 9 for brittle rock = 10 for very brittle rock = 10 – 15 for coal k2 = influence of discontinuity such as joint, bedding plane etc and, = 1 for massive and discontinuity distance > 25 cm = 1.5 – 2 for layered/fissured, thinner bed rock, discontinuity 10 – 25 cm = 2.5 for layered/fissured/interbedded rock discontinuity <5 cm k3 = influence of specific cutting condition and is a function of no sumping, cutting height, cuter head oscillation, pick array, pick shape. However, for roadheader its value ranged from 3.5 – 4.5 Copur et, al. (1997, 1998) RPI =(P×W)/UCS ICR = 27.511×e<.<<#Z×h{y Where: ICR = Instantaneous cutting rate (m3/hr) RPI = Roadheader penetration index W = Roadheader weight (te), P = Cutter head power (kw) UCS = Uniaxial Compressive Strength (MPa) #"! $%% & & ! " # $ % & = !"# !$%C D' ! " # $! ! " = ! " " " # $! # " ! $ % % % % " " =
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