ABSTRACT: Continuous rock cutting technology is steadily advancing, with the development of undercutting-disc systems for hard rock applications progressing to the commercial prototype stage. Building on research supported by ACARP that investigates the potential for this technology to be applied to surface coal mining for overburden removal, an economic evaluation is presented to assess potential costs and benefits.
A case study deposit was utilised to examine various mining fleets based on a boom-style cutting machine, including comparison with a conventional drill/blast operation. Several material transport systems were considered: haul trucks, conveyors, and hybrid systems incorporating de-coupled tucks with hopper-style transfer stations. A key finding is that the break-and-load Operating Cost (Opex) for the cutting systems is higher in all cases for this deposit scenario than the baseline case (drill/blast/shovel), by 50% or more. The results also indicate that the haulage Opex for the cutting systems varies considerably, depending on the transport method. Direct truck haulage of cut material has higher Opex than the baseline system, due to the larger fleet requirements and increased loading duration, whereas a conveyor transport system provides a more cost-effective haulage solution compared to the baseline.
The analysis further suggests that whilst the capital and operating costs on a per unit basis ($/bcm TMM) may be higher for a cutting system, when compared to traditional mining methods however, there are significant benefits that are unique to a cutting system that can indeed result in a better overall economic outcome, depending on the specific nature of the deposit and various operational constraints and opportunities. Such benefits include direct value offered by the potential for steeper pit slopes and increased coal recovery, as well as indirect yet tangible value through elimination of blasting-related impacts (e.g. fumes, noise and vibration), process simplification, automation potential, improved safety and lower emissions.