The uniaxial compressive strength (UCS) is a key factor for examination, whether roadheader cutting head used or not. It varied with the capacity of roadheader or its cutting head, but it was generally known that roadheader cutting head was useful less than the UCS of 100 MPa. This study performed a series of linear cutting tests in the condition of different penetration depths, cutter spacings by using a slim conical pick for the light cutting condition. Two dominant rock types in Korea is granite and gneiss. They were unsuitable for linear cutting test in the range of less than 100 MPa, because they exist in weathered or soft rock form with discontinuity. In this study, cutter forces were measured by 3-directional load cell on the mortar specimens with the different UCS. The variations of cutter forces and the opt. S/d were examined depending on strength change of specimens. And the cutter forces from the experiments were compared with those predicted by the existing prediction models of cutter forces.

1. Introduction

Pick cutters are used in partial face machines such as roadheaders and continuous miners. Recently, conical type cutters is most commonly used for partial face excavation work because their performance is well maintained during working time (Hurts and Evans, 1981; Kim et al., 2012). Three-directional forces are applied to the tip of the cutter during cutting of a conical pick. The cutter acting forces are very important input variable for the cutting head design. They are used to calculate the required thrust, torque and power of the cutting head of a partial face machine (Balci et al., 2004; Copur et al., 2011). This study measured the cutter acting forces on the mortar specimens with the different Uniaxial Compressive Strength (UCS).

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