Drillhole EM – a strictly scientific Hokey-Pokey

Examples of drillhole EM (DHEM) from the Eloise copper-gold ore deposit, Queensland, show how EM methods can contribute to exploration and resource evaluation drilling programmes, by determining existence and extent of conductive mineralisation above and below a drillhole, along strike and off-section. Multiple conductors respond with differing transmitter coupling and time-constants, and can be identified by the use of multiple transmitter loops; an extreme example shows how four separate conductors can be identified in one drillhole with the use of five transmitter loops. © 1996, CSIRO. All rights reserved.