ABSTRACT
The accidental curved or spiral wandering common to most boreholes is known as borehole deviation and is distinguished from deflection, which indicates a borehole trajectory which has been reorientated away from some former course by the drilling engineer using technological methods. This chapter offers considerable potential for both reducing costs and increasing the quantity of information obtained from exploration core drilling in deep mines. It is primarily designed for use at the bottom of existing deep-level workings where there is limited strike development available for simple short-hole exploration programmes and thus few opportunities for evaluating downdip extensions of the mineralisation. Thus, in order to demonstrate the advantage of the proposed system its technical constraints are discussed, the operation of computer analysis demonstrated and the system then evaluated for a typical deep-level Cornish tin mine.
