Drill holes in rock are rarely straight. Rock, h:>le drilling equipment, drill operators, hole plans – are among the several contributing factors to hole deviations. Little is actually known about the hole deviation phenomena, but economic consequences in mining, oil, construction and exploration industries are undoubtedly enormous.
In this thesis the results of a field study are presented, in an attempt to shed sane light one of the least understood phenomena, namely: rock dependent hole deviations. In order to reach a reasonable statistical conclusion and still keep the costs of the study limited, this study was carried out on holes that remain in rock walls after smooth blasting in road-cuts, open-pits, and quarries.
Thephenomena and statistical results of the study clearly indicate that rock structural properties do have an influence on the amount and direction of hole deviations in such a way that one can actually predict the future deviations if the rock structure, hole plans, and drilling conditions remain the same in the area. Based on evidence from hole paths in layered and jointed rock structures, a qualitative theory is finally presented to explain the ”up-dip” and ”down-dip” hole deviations phenomena.
The BeFo publication hereby presented contains in essence a summary of a licentiate thesis at Luleå University with registration no 1986:07L (140 pages). Any reader who would be interested in further details is kindly referred to this publication.
