Cash flow vs. cut-off grade criteria for mining planning and production scheduling - Case study on an underground gold mine

The influence of cut-off grade criterion on the short time cash flows (for instance, in the case of small mines) could be crucial. Yet management decisions to improve cash flows have strong linkage with the current cut-off grade criterion. To tackle with such problems, a package of programs for mine planning and operational control was developed and is described. The program takes into account mineralogical and metallurgical characteristics of the mined material. The first step is the construction of a typology of the ore to be mined based on its mineralogical and minerallurgical characteristics. After the definition of the mine preparation works (shafts, drifts, etc..) several mining policies can be adopted. To each policy corresponds one time series of run of mine material which will be processed in the concentrator under the criterion of “maximum conservation”. Besides, to each output of the concentrator corresponds a cash-flow and several additional economical indicators. The program is interactive so that the operator can choose the policies he is interested to. An example concerning an underground gold mine is presented.