Calculating Ore Reserves Using A Digital Computer

All ore reserve estimates are based on some system for assigning an area of influence to each drill hole. Commonly used methods of calculation are the polygonal, triangular, statistical analysis, and cross-sectional. Each of these methods is based on different volumetric considerations and the weighting of grade with tonnage varies with each method. Because the characteristics of each mineral deposit are different, a preliminary survey of these characteristics should be made for each individual deposit to determine which method or methods should be used. In this project the several methods were not only compared with one another, but also against actual production records. Basic data was derived from a mined out portion of the Silver Bell pit near Tucson, Ariz. All calculation was carried out on a digital computer, and the first step was development of computer programs which would yield the desired information. The second step was the coding of input data into punched card form. Cost and speed of computer operation were measured, and these results are given with the computer program summaries on page 38.