Stebbins, S 2015, 'Cost estimates as a design tool — the impact of mine design on ventilation costs for a variety of underground mining scenarios', in Y Potvin (ed.), Design Methods 2015: Proceedings of the International Seminar on Design Methods in Underground Mining, Australian Centre for Geomechanics, Perth, pp. 463-473, https://doi.org/10.36487/ACG_rep/1511_28_Stebbins
(https://papers.acg.uwa.edu.au/p/1511_28_Stebbins/)
Abstract: While an abundance of factors drive the design of an underground mine, the operation may simply not make a profit unless each of the aspects that directly impact costs is considered in that design. Too often, an unforeseen or unanticipated cost parameter, such as the power drawn by the ventilation fan, begins to undermine profitability after it is too late (i.e. too expensive) to remedy the oversight.
The task of supplying adequate volumes of fresh air to the more remote areas of a mine is crucial to underground operations, and the costs of doing so must be considered early in the design and feasibility process. It is, of course, difficult to predict future ventilation requirements to any degree of reliability, given the limited amount of information typically available early in the design phase. However, some relatively representative values can be achieved if evaluators focus on the parameters that determine these requirements and costs.
The following discussion serves to describe mathematical approaches that can be used to incorporate such costs directly into a design, thereby providing a basis for equipment size and opening dimension selection procedures that directly considers economic impact. While the results that are displayed in the following pages were obtained using a commercially available software package, the paper itself details the critical algorithms and suggests an approach that individual evaluators can use to set up their own spreadsheetbased models.
The focus of our work is six critical (along with several less important but influential) ventilation cost parameters. Fresh air volume requirements are first and foremost, and these are based upon machine and workforce specifications. Next are the length and the perimeter of the openings through which fresh air is delivered to the workings and through which it is evacuated to the surface. In addition, the texture of the exposed surfaces must be considered along with the dimensions of the active working stopes. If the evaluator can estimate the machine and workforce requirements, the length and perimeter of the access openings, the texture of exposed surfaces and the dimensions of the stope, then it is possible to reliably estimate ventilation costs.
While the data that defines them may not be readily apparent or available, most of these parameters can be reliably approximated. And, once the math is in place and the system modelled, an evaluator can see the relative importance of each parameter to their specific project. Such modelling can be used to provide an indepth study of the balance between machine type, machine size, opening dimensions and workforce requirements; with the results in hand, adjustments can be made to enhance economic viability.