Downhole Geophysics Project 1986-1990: Final Report

The Downhole Geophysics Project began in 1986 as a joint venture of coal and oilsands mining operators, consultants, geophysical companies, research organizations and government agencies. The group has studied the use of downhole geophysics to determine geotechnical and hydrological parameters in overburden materials. The ultimate objective has been to decrease costs and increase data availability, continuity and accuracy for coal and oilsands exploration, open-pit mine planning and operations.

Engineers must address a variety of problems when designing and operating surface mines. These include stability of highwalls and spoil piles; diggability of overburden materials; the ability of overburden and pit-floor materials to support mine equipment; and the impact of groundwater on the mining operations and materials handling. Geological, geotechnical and hydrological factors play major roles in solving these problems.

In the mining industry, downhole geophysical logs have rarely been used to obtain geotechnical and hydrological data. However, a suite of natural gamma, resistivity, density and calliper logs is normally run in most coal and oilsands exploration drilling programs in western Canada and in some instances supplementary neutron, sonic and dipmeter logs are also run. The logs are used primarily qualitatively, to determine geological stratigraphy and to verify the depth and thickness of ore zones. Extending the use of the logs to the quantitative determination of geotechnical and hydrological information would have immediate practical and economic benefits, as would identifying new logging tools that should be applied to these problems.