Analysis Of Metallogenic Conditions And Metallogenic Prediction In The Xiyi Pb-Zn Deposit Based On 3D Digital Model, Yunnan Province

Yunnan Xiyi Pb-Zn deposit is located in the middle of carbonate platform of Baoshan Block. After many years’ prospecting, the Pb+Zn reserves are up to a large scale and its prospective reserves can be up to a super large scale.This study is guided by “three levels integrate into one” ore-prospecting theory and method, operated by means of Surpac, Mapgis and AutoCAD software and based on mining the traditional geological information and applying geostatistics to build a 3D geological model for metallogenic conditions analysis, reserves estimation of V3 orebody and concealed orebody prediction in the principal study area-Dongjiazhai ore section. It can provide theoretical and technical support for drillhole layout and enlarging prospecting achievement.The Geological Database and 3D modeling of surface, orebody, strata, fault and dyke have been built through analyzing and arranging the data of Dongjiazhai ore section collected from Dali Geological Institute. The topographic relief is small. The slope is smooth and the altitude difference is little. The fold develops which impacts and varys the thickness of strata. Fault F17 has a simple form and gentle extension. The subsidiary fracture develops. The diabase dyke is broken which cuts through strata and fault. According to this we deduced that the diabase dyke formed after the formation of Lower Carboniferous Xiangshan Formation and it’s unrelated with Pb-Zn mineralization. The form of orebody V3 was similar to that of fault F17. The space variation of orebody V3 was little and the extension was smooth.Through geostatistics analyzing and applying Kriging method, the reserves of Dongjiazhai V3 orebody is estimated. The total ore reserves is 20.55 million tons. The total metal(Pb+Zn) is 0.9 million tons. Among them, Pb is 0.46 million tons; and Zn is 0.44 million tons; the associated Ag with above 2g/t grade is 8.01 million tons.Through 2D and 3D metallogenic prediction of Dongjiazhai ore section, the prospecting target was confirmed. By means of analyzing contour map of element anomaly and orebody thickness in 2D prediction, the flow direction of ore-bearing hydrothermal fluid is speculated. The result is that hydrothermal fluid flowed from northeast to southwest along fault F17 on the plane and from northeast lower part to southwest upper part of orebody on the vertical plane. By means of analyzing and extracting of each ore-controlling factor and calculating the weighted value in 3D prediction, the ore-controlling factors are marked. According to the classification of synthesis scores, the predicting area with scores greater than 0.6 is divided into two kinds. One is first class predicting area with score greater than 0.64; the other is second class predicting area with score between 0.6 and 0.64. The former is located at northwest of orebody V3 where the elevation is from 800 to 1100 m. The latter is divided into two parts: area A and area B. The area A is located in northwest of orebody where the elevation is from 680 to 900 m. The area B is located at northeast of orebody where the elevation is from 800 to 1200 m.