Resources prediction geochemical method in deep area for old orefield—a case study of Chengmenshan copper deposit about copper deep area resources prediction, Jiujiang County, Jiangxi Province, China

In order to improve resource base and guarantee long-term development for old mines, resources predicting and calculating for deep area are imperative under current situation. This paper has researched into Chengmenshan copper (Cu) deposit about Cu deep resources prediction, Firstly certain Cu-enriched geological body has been selected as research target, then by applying fitted function and three-dimension (3D) geological visualization modeling, principles and detailed process by means of integral planar metal quantity and 3D geological body block method are discussed. Two methods has been managed to calculate resources in the range from 0m to -500m (the first space range) and -500m to -1000m (the second space range) in depth respectively. Both of them are feasible for the first space and the results are quite similar compared with the results by traditional method, while 3D block method is preferable for the second space. In conclusion, when the ore cut-off grade index is 0.3% and 0.2% respectively, by using the second method, corresponding results are 57.970×104t and 137.580×104t; besides, deep resources are mainly concentrated in layer-like Cu-enriched pyrite (namely No.Ⅰ ore body).