Applications of downhole SIROTEM surveys in the Agnew Nickel Belt, WA

Abstract

Field examples of downhole SIROTEM surveys investigating massive sulphide targets in the Agnew Nickel Belt, WA are presented to highlight different applications of the technique. The examples show that the downhole EM (DHEM) method can successfully solve specific exploration problems posed by initial drilling of a prospect. Such problems include: the presence or absence of deep conductors in favourable geological positions; the location or confirmation of the source of a surface EM response; the resolution of the geometry and extent of a drilled conductive target; and the effect of conductive overburden on surface and downhole EM responses. Interpretation of the Agnew DHEM survey data, based on computer forward modelling aids, shows good agreement with drill indicated conductor positions. The results demonstrate that the DHEM method represents an efficient and cost-effective means for second phase exploration for massive sulphide targets.