Design Of Drill Hole Patterns And Spacing

INTRODUCTION Much discussion has been generated over the years among geologists and engineers as to the ideal drill-hole configuration and spacing for evaluating various types of mineral deposits. Little can be found in the literature about the outcome of the programs, probably because of their subjective nature and the then lack of suitable means of scientific testing. In years past the drilling patterns and sequence were almost entirely determined by the experience and personal bias of the senior engineer, geologist, or project manager on the job. However, planning a drilling program- spacing, pattern, sequencing, etc.-is simply a specific case of sample design, or the design of a sampling program. Having been exposed in the preceding chapter to the theory of regionalized variables, and having learned something about the tools for measuring correlation, or lack of correlation, among samples within a given mineralogical population, we are now prepared to apply these concepts and new-found parameters to a scientifically designed mineral sampling program, be it by drilling or other means. FACTORS IN SAMPLING DESIGN It was shown in Chapter 8 that three major factors should be considered in any mineral