Ore reserve estimation at the Enterprise Gold Mine, Pine Creek, Northern Territory, Australia. Part 1: structural and variogram analysis

CIM Bulletin, Vol. 81, No. 909, 1988

NEIL SCHOFIELD, Applied Earth Sciences Department, Stanford University, Stanford, California

The Pine Creek gold mineralization is associated with saddle reefs andquartz and'quartz sulphideveining within theEnterprise Anticline. The anticlinal structure is complex and the mineralization was considered prior to development to be dominantly strata controlled. Gold grades vary up to 160 g in 1.5 m core samples with coefficients of variation in excess of three.The estimation of ore reserves for such a deposit must account for both the geological complexity and the extreme variability of gold grade. This paper describes the structural and variogram analysis of the gold grades and demonstrates the importance of incorporating the geological model in such an analysis. Variogram interpretation is greatly improved and greater insights into the finer geological structure are provided. Part 2 of this work presents the application of multigaussian kriging to reserve estimation for deposits with highly variable grade and which consequently demand highly selective mining operations.

Mots Clés: Geology, Ore reserve estimation, Gold mineralization, Mineral deposits, Structural analysis, Variogram analysis.