| No.92 ore-body is the biggest ore-body of Dachang tin-Polymetallic ore-field in Guangxi province, China's most important tin-producing district. This paper synthetically analyzed the geological and geochemical characteristics and the metallogenesis of No 92 ore-body. As one of the advanced reserves-estimation methods, geostatistics has been widely applied in geology and mining- industry in the world. In this paper, the new techniques of computer, geostatistics theory and methods are firstly applied to establish the mathematics-economic model of No.92 ore-body. The successful application of geostafistics on modeling on No 92 ore-body has important significance to the dynamic management of mining production and the rational exploitation of mineral resources The main results are listed as follow: The study on No.92 ore-body indicates that it is an exhalative hydrothermal sedimentary-transformed type in genesis The ore-body is composed of banded stratiformed mineralization and vein-like mineraliziation. In the previous stage, the banded and stratiformed ores and ore resources layer were formed by spouting hydrothermal sedimentary in the northern-eastern part and in the lower horizon, In the later stage, the vein and veinlet ores were formed by structure-reformation in the western and in the upper horizon With the respect of material resources, the mineralizing materials is from exhalative sedimentary mineralization, it has no obvious relation with Yanshan granite, Yanshan granite mainly provided the energy and motive power for transformed mineralization in later stage No.92 ore-body can be divided into three layers upper, middle and lower Upper and lower layers are Sn, Pb,Zn ore layers, middle layer is Zn, Pb ore layer The mineralization of upper ore layer is the best, that of lower ore layer is the second, and the middle ore layer is bad No 92 ore-body is hosted in D3 siliceous rocks, occurred in bedded shape, conformable with the strata and synchronously folded with the strata. The most important ore-controlling factors are tectonic, structure and strata All those studies not only enriched the metallogenetic theory of Dachang tin deposit, but also provide the basis to determine the ore-body correctly. The original database of No.92 ore-body has been established There are 516 prospecting projects including their tree dimensionality coordinates. 25000 samples and 90000 analyzed data of Sn,Pb,Zn,Sb and Ag in the database. Fundamental statistical analysis shows that the values of Sn, Pb and Zn are logarithmic and normal distributed and their variant coefficients are 196%, 153%and 101% respectively The database can be used by the mining dynamic management whenever necessary The variogram of No 92 orebody in five directions have been calculated, and the variogram curves were formulated All these curves are leap type The mathematical models of grade varialbility of Sn, Pb and Zn have been established separately, the structural analysis of No.92 ore-body indicates the ore-body varies band anisotropically. Cross testing and verifying shows that the estimation error is in the allowed range Aiming at that No.92 orebody changes greatly in morphological characteristics, the new method to respectively estimate depending on the occurrence is firstly applied, lithology model of No 92 ore-body is established And the hthology value is estimated in blocks of one model By means of kriging, the grade model of No 92 ore-body are established, the grade values areestlmated by the un1t of 10X 10X2. 5 cube meters ln voIume, the re5erves of Sn, Pb and Zn arecalculated by tCn dlfferent cut-off grades, and the mlnlng econo...
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