| A geostatistical study is carried out on the Pipeline Gold Deposit, Lander County, Nevada. The mine experiences a difference between the long-term estimates of tons and grade, using exploration data, and the production estimates using blasthole data. Three possible reasons for this difference are investigated, namely (1) the estimation method (currently indicator kriging is used), (2) the density of exploration data, and (3) the difference between the grade distributions of the exploration and blasthole data.;Ordinary kriging results are compared to indicator kriged estimates. Blasthole data on different spacings are used to assess the effect of the exploration drillhole density on long-term estimates.;It is found that the major reason for the difference is the wide spacing of the exploration data. Changing the estimation method does not improve the long-term estimates however; the simpler process of ordinary kriging can be used with no meaningful difference in the results. |
