While mechanized mining operations are integral part of mining activities in soft rocks, drill and blast fragmentation method still dominates the hard rock mining operations. Mechanized fragmentation technology for hard rock mining should be robust, relatively small, and flexible; however, development of such system has been a challenge due to energy requirement of cutting hard rocks and the short life span of the cutters. These limitations strongly suggest the need for alternative solutions to reduce the energy requirement of hard rock failure. Actuated Disc Cutting (ADC) is a new dynamic cutting method, which uses disk-shape cutters attacking the rock in an undercutting mechanism. This new system dynamically actuates the cutter, while it is moved across the rock. Breaking the rock under direct tension, ADC consumes less energy for fragmenting rock than conventional methods, hence, reducing the overall power requirement of mechanical hard rock excavation. Introducing the characteristics of an ADC system, this paper summarizes the findings of an experimental study, which investigates the rock failure mechanism and the forces associated with the cutting process using a laboratory ADC test unit.
Application of mechanized cutting/fragmentation technologies in hard rock mining environment is impeded with the limitations of the existing technologies: being power, size, mobility, and cutter life. Overall there are two main classes of cutting tools: drag cutters, such as picks, which are used on road header type machines; and indenters, such as roller disc cutters, used on tunnel boring machines. Drag cutters are more efficient tools than indenters by directly encouraging tensile cracks when moved across the rock surface at a certain penetration depth. Indenter, however, are more wear resistant, due to the rolling mechanism of the cutter, while requiring higher forces for breaking the rock under compression induced tensile failure. Susceptibility to wear and failure has therefore limited the use of drag cutters to excavating low-to-medium strength and non-abrasive rocks (Ramezanzadeh and Hood, 2010); indenters, on the other hand, despite their need for very high thrust forces, have found widespread use in full-faced hard rock cutting of civil applications, where large and heavy machines can be used.
