Drillhole electromagnetic surveying in the mine environment

Abstract

An efficient and effective exploration strategy for further resources is important for large scale mining operations such as Mt Isa where the depth and scope of the operations means that a proportionately larger volume of highly prospective rock is available for exploration.The application of drillhole electromagnetics (DHEM) allows the effective radius of exploration from a single drillhole to be significantly increased, thus decreasing the cost of discovery. Typically this type of near- and in-mine exploration will utilise directional drilling technology from the surface or underground. Such holes commonly have sections with inclinations too shallow for conventional DHEM, which relies on gravity to move the probe. This paper describes trials undertaken by MIM Isamine which were designed to overcome the problem of surveying shallow dipping to upwardly inclined drillholes. Various logistical, operational and safety aspects are also addressed which cumulatively produce a working system and help minimise noise.