A Study On Application Of Multiple Kriging Methods In Solid Mineral Reserve Estimation

In China, the main method of geostatistics used in solid mineral reserver estimation is ordinary kriging at present. The reasons are that the application of ordinary kriging is simple comparatively and can always get a reasonable result. The non-linear and non-parametric kriging is more reasonable in theory, but because of the complication of its parameter, it is easy to get an error result, if you don't know how to define the parameter. A few academicians work over the applicability and setting of parameter of non-linear or non-parametric kriging, which causes the fewer applications of non-linear kriging. Now the theory research of Multi-kiging has developed riped, but this cause the choice of kriging method become a very important problem. At present there are very few empirical validation studies that compare non-linear kriging with each other and with linear kriging. The promotion of geostatistical application was tardo in solide minearal reserve estimation. It needed to be solved. This article based on the basic theories of geostatistics and kriging methods, using real data gotten from big exploration engineering of big metal mine, via a great deal of experiments, provides the methods of setting the parameter of non-parametric kriging and compares the precision and uncertain of the common kriging methods.This article first deeply researched the theory of indicator kriging which is a non-parametic kriging method, and then used the common methods of setting the cutoff (using the equal quantile and using the equal space) in the indicator kriging estimation, and then analyesed the statistical result and the distribution of the data. Through this we knew that the two methods of setting the cutoff caused the error result. According to the kriging result and the distribution of the error, this article pointed out two new methods of setting the cutoff (using the methods of equal quantile and equal space simultaneity and the normal distribution) and used in the indicator kriging and got very good result. At the same time the article analysed the parameter of the whole indicator kriging and pointed out the whole indicator kriging process and the method of setting parameter of the indicator kriging. At last the purpose of this artical is to provide a reference of the use of the indicator kriging in the solid mineral reserve estimation.This article used the statistic criteria in the compare of the precision and uncertain of the several kriging methods. The kriging methods include ordinary kriging, lognormal kriging, multiguass kriging and indicator kriging. According to classify the result of kriging and compare the correctness between the result of kriging and the original data, we can analyse the pnts and cots of the several kriging methods and the characteristic of the distribution of the kriging result. Several result we can get according to the criteria of the precision of the kriging and the correctness of the sort between the kriging result and the original data.(1) The linear kriging methods and non-linear kriging methods have similar estimation precision result, more over the precision of the linear kriging is more high.(2) Lognormal kriging can result some system error, Although at this research we used the unbiased backtransformation, because of the skew of the orginal data and the biased of the lognormal kriging, which caused the high estimation result. (3) Multiguass kriging has similar precision result with the other kriging methods, and its variance is equal to the original data's, but its local estimation result has a distance with the orginal data.(4) Indicator kriging is more equal to the orginal data in the middle than the other kriging methods. Because at this research we used the median indicator kriging.(5) The uncertain of the non-linear kriging is over the linear kriging, especially to the untaildata.(6) The uncertain of the multiguass kriging is the best in all the methods of kriging.Those result can provide some references of the use of the geostiatistcs in the solid mineral reserve estimation.At last, according to the references about the methods of setting the parameter of the non-parametric kriging and the precision and uncertain of the several kriging methods, this article choices two kriging methods and uses them in the reserve estimation of the real deposit. The discrepancy between the results of the two methods is lower than 5%.