A Study On Several Issues On Application Of Geostatistics In Solid Mineral Resources Estimation

The promotion of geostatistical application was tardo in solid mineral resources estimation though there has been 30 years since the introduction of geostatistics into China. The reasons are that there is no exact indication for selecting estimation methods, no abundance of experience of choicing key parameters and no effective method to classify the estimation results accorging to the specifications of exploration and national standard of mineral resources and reserves classification.In order to clear the obstacles in the ways of promotion of geostatistical application, via a great deal of experimentals, this dissertation provides a maneuverability answer to the problems hereinbefore mentioned based on the basic theories of geostatistics, using real data gotten from big metal mine and from exploration engineerings of big scale mineral properties.From the study of basic geostatistics theories and the meaning of 5 kinds of kriging methods, this dissertation gives the conclusion that the normal distribution of data is not a necessary condition. After Investigating how distribution affects the estimation results, the dissertation suggests that the coefficience of skewness serve as a indication in methods selection between ordinary kriging and lognormal krging used for resources estimation.This dissertation gives the practical sources and theoretic reasons of nugget effects. Collecting the real data from mineral properties, the dissertation researches the impacts on resources estimation and on determination of searching scope when using defferent nugget effects, points out that estimation error would increase on condition that big nugget value. The dissertation suggestes that one should think over the variability of variables measured from drillholes, the variablility of variables measured from whole mineralization domain and the variability of variables measured from one direction. The dissertation also briefly discusses how the nugget value affects on search domain.The existed methods on classification of mineral resources and reserves have some limitations based on the geostatistics methods when block serves as target unit in resources estimation. According to the general specification on solid mineral exploration, all kind of specified mineral exploration specifications and national standard on solid mineral resources and reserves classification, this dissertation brings forward an easily performed method to classify mineral resources and reserves. This method meets the practical demand and provides the opptunity to take into account the characteristics of geostatistics, the geological assurance of mineral resourcea and reserves and the scopes of feasibility study.