Development of a multiple level underground limestone mine from geology through mine planning

Abstract

The development of a multiple level underground mine is a complex task in which geology, engineering, ground control, and unit operations are integrated into a single mine design. The components are inter-dependent and must function cohesively to ensure a profitable underground mining operation. To optimize reserve recovery, mine planning should begin from the lowest level and progress up. This limits any misjudgments or oversights of a given level affecting the underlying levels and ensures the ability to maximize recovery from each level. Mine planning should start with the exploration and characterization of the geologic setting. Once the reserve geology and quality is well understood, then mine planning can begin with respect to the following: (1) orientation of mine works with respect to horizontal stress; (2) access to the reserve; (3) determination of opening widths; (4) selection of back, floor horizons and pillar centers; (5) selection of development and secondary mining heights; (6) appropriate inter-burden thicknesses; and (7) examining the stability of the multiple level mine through numerical modeling. The multiple level mine design process and decisions are presented through a case history example. The theme is that there is one opportunity to “get it right” and many chances to overlook a small aspect within the design that will plague the mine throughout all levels and through the entirety of its operating life.