Geological hazards such as faulting, basement ridges, and zones of "thin"
(< 6 m) coal have a major impact on mining economics of underground
operations in Huntly Coalfield. Experience has shown that drillhole-based
investigations do not yield sufficiently detailed models of the coal seam to
allow management of the planning risks associated with these hazards.
Consequently, operational performance is affected by unplanned costs associated
with lower productivity, loss of coal reserves, and expensive strata control
remedies in problem ground conditions. Huntly Coalfield is a challenging
environment for acquisition of good quality seismic reflection data due to the
very thick (10-85m) weathering layer. Since 1994, successful acquisition of 2D
and 3D data has been achieved through a combination of careful testing of
technical parameters and experimental trials prior to committing to production
recording. High resolution seismic reflection (HRSR) is proving to be an
investigations technique which generates accurate and reliable models of the
coal seam and associated structures, such as normal faults and topography of the
surface on which the coal seam rests. The HRSR technique has been applied and
developed in the Okowhao Sector where Huntly East Mine is developing and
extracting coal reserves. Results of a recent 3D survey demonstrate that this
technique is capable of revolutionising risk management in mine planning for
underground mines in structurally complicated coal deposits.