ABSTRACT
This paper aims at demonstrating the optimum Percentage of Resource Mined (PRM – mineable reserve divided by total ore resources) by means of a parametric analysis, given three ore body geometries, namely: tabular, cylindrical and pipelike, showing the threshold between open-pit and underground mining, using the so-called Ore Quality Factor (OQF), which will be defined in the text. A conycal open-pit mine was considered to calculate the OQF, the economics of underground mining to go beyond the established limit by underground mining being not considered, which, in the case of the pipelike orebody would be more important. The relative dimensions of the aforesaid shapes were chosen in a way, that resulting volumes are the same and therefore tonnages. The overburden thicknesses considered for the three shapes being the same, the waste-to-ore ratio varies a lot, whether PRM is 10% or 100%. Sensitivity analyses included overburden thickness, ore grades, and slope angles.
