Study On Localized And Quantitative Prediction Of Concealed Deposits In The Eastern Gejiu Deposit

Gejiu tin-copper polymetallic ore deposit, located in the metallogenic belt of Southeast Yunnan, is famous for its huge Sn reserves, numerous mineralization type and very long exploitation history in China as well as in the world. However, after several decade exploitation, the known resource has almost exhausted. Gejiu are suffering shortage of resources. Hence, it has important realistic to carry on mineral recourse exploration using new theory and method. With the purpose of looking for succeeding mineral resources, the paper conducted the Study on Localized and Quantitative Prediction of Concealed deposits in the external and deep of Gejiu eastern district.GIS and computer technologies were the main tools used in this study. Based on the metallogenic information mining and extraction on the traditional geological data and other exploration information, under the guidance of the newest ore-forming regularity, using the theory and methods of mathematical geology, this paper conducted three levels mineral resources prediction researches based on different known exploration data in Gejiu eastern area. Namely: (1) mineral prediction based on multi-bands remote sensing data. (2) synthetic information based on geological, geophysical, geochemical and remote sensing data.(3)three dimensional concealed ore prediction based on high resolution exploit dada using digital ore deposits model method.The first level prediction was based on mainstream multi-spectrum remote sensing data ETM and ASTER. The author discussed how to pre-process these two data firstly, and then extracted structure, lithology and alteration information using proper processing methods. Through the establishment of regional geological prospecting model, favorable ore-forming area was delineated using the extracted remote sensing metallogenic information. The second level prediction was based on many multi-source geological data including geological, geochemical, gravity, airborne magnetic and remote sensing data. Under the guidance of regional metallogenic regularities and the geo-anomaly ore forming theory applying, nine diagnostic deposits recognition criteria layers are extracted from those geo-data sets And then, these deposits recognition criteria layers are combined in the weight of evidence (WolE) model which uses the spatial correlations between the evidence lays and the known mineral occurrences to calculation the posterior probability map and indentify the delineate the prospective area. The third level prediction was based on high resolution geophysical and geochemical data, as well as the geological profiles. Through establishing 3D model of geological units using exciting commercial 3D modeling software, the author extracted 3D metallogenic recognition criteria. And then conducted concealed ore bodies prediction"using cube Prediction model"method.The first and second prediction results show that peripheral areas of known ore fields are still with great potential for mineral exploration.The most favorable target area is located in the eastern flank of Laochang ore field. The third level prediction shows that the most promising location for reconnaissance drilling is (X: 126000, Y: 57700, Z: 1150; X: 126300,575800, Z: 1150; X: 125000, Y: 578800, Z: 1710; X: 125600, Y: 57800, Z: 1700). And Sn resource with the grade above 0.07% is estimated to be 9465 tons.