A Study On Optimum Cut-Off Grade Policy And Economic Exploitation Of Polymetallic Deposits In Underground Mining

Abstract:In recent years, with the rapid development of China’s mining industry, a lot of easy mining, high grade deposits are nearing close. Based on the characteristics of metal mineral resources in China and the need for future development of industrialization in China, mining targets will gradually expand to low grade, polymetallic deposits with complex occurrence conditions. How to mining these deposits, one of the most basic and the most important task is to solve when the deposit is profitable and mining what grade deposits can bring the greatest benefits to the enterprise, also known as the cut-off grade optimization. On the other hand, China’s current "double index" system is put out in the planned economy period, it has played an important role in the development of China’s mining industry, with market economy developing in our country, the current industrial index of mineral is no longer adapt to the development of mining industry, with needing change urgently.In view of the above problems, based on economic problems in mining, we focuses on the determination of optimum cut-off grade policy in underground mining, and carry out the research work of economic optimization of mining method, the main contents of this paper include the following aspects:(1) The cut-off grade indexes system is composed of geological cut-off grade, designed cut-off grade and production cut-off grade. We define the concept and significance of three kinds of index. Based on the modern theory and method, with the foundation of the previous study, the general mathematical model of the three kind boundary grade indexes is proposed to solve this kind of complicated mathematical model algorithm.(2) Based on the platform of DIMINE(?), we establish the3D borehole database and mineralization domain model of Shaxi copper deposit. Using geostatistics method, we assess the different grade interval ore amount and metal weight, rendering the grade and tonnage curve.(3) Considering the main factors affecting the cut-off grade, we study its relationship with the cut-off grade, and determine the corresponding economic parameters. According to the proposed algorithm, we develop the corresponding software of optimum cut-off grade policy (OCGP1.0), then we present the results of geological cut-off grade, designed cut-off grade and production cut-off grade in Shaxi copper deposit.(4) With constructing profits constitutive equation, we compare the one step mining method with the two step mining method in Shaxi copper deposit, at last, we draw a conclusion.Ideas and results in this paper have a significance in increasing the recovery rate of resources and mining profits, and raising the technical level of enterprises.