A mine simulator model is used by the Bureau of Mines to evaluate the economics of a mineral recovery operation. This document explains the computations performed in this discounted cash flow rate-of-return (dcfror) procedure and the use of a Lotus 1-2-3 (r) template version (pcminsim) of this model. A minsim evaluation combines reserve tonnage and grade estimates and the associated capital and operating costs with information about financial and tax conditions to simulate the DCfror that can be expected over the life of the mine. Solution options include the net present value (npv) of the property, the average total production cost over the life of the operation, or the after-tax rate of return expected at an assumed selling price for the marketable product. Running pcminsim is simplified by 11 tiered menus that direct the user through the evaluation process. The main contribution of the pcminsim is the use of automated spreadsheet technology to illuminate the relationships inherent in a DCfror evaluation, to expedite interactive sensitivity analysis, and to facilitate modifications to explore new applications of this property evaluation tool.