The Strength of Massive to Moderately Jointed Rock and its Application to Cave Mining

Abstract

The early understanding of the rock masses in which a mine will be constructed and operated is of fundamental importance and required for developing reliable designs. To assist such understanding, this contribution is focused on massive to moderately jointed rock mass domains, their behaviour under load, rock mass strength, assessment, and implications to some cave mine design elements. Since more cave mines are being studied, constructed, and operated at greater depths, the need to understand and design in high stress and in massive to moderately jointed rock mass conditions is critical. Cave mines, by their nature, are vulnerable to disruption from unanticipated rock mass behaviour and at risk for unreliability. Cave mine excavations and their geometric layouts are constructed early in the mine life (when there is limited understanding of the rock mass and its response underload) and have minimal flexibility to be modified as experience is gained in the rock mass. They are thus fragile systems. Many design aspects that have a large financial impact on the investment value of a cave mine have the potential to be negatively influenced by unplanned or inappropriately considered rock mass conditions.