Analysis and selection of borehole composite length for accurate and optimal geological resource reserve calculation: A case study of timulike iron deposit

Standardizing the length of borehole samples is one of the essential steps in the estimation and calculation of geological resource reserves with contemporary software such as Surpac. This standardization resulting in a composite chain file has a significant impact on the accuracy and optimization of the estimate. Unsuitable composite lengths can lead to underestimating or overestimating these resource reserves. This article helps remedy this problem in the case of the Timulike iron deposit in China. The geological data are first processed in Microsoft Excel using standard mathematical computation and the iron content curve to rectify, filter, rearrange, and readjust them in files in the Surpac format. After that, the anomalous results were checked and corrected using the histogram analysis and cumulative frequency of the iron contents. Afterward, 30 composites with lengths ranging from 0.5 meters to 10 meters are constructed using the Surpac software's composite construction approach and data from the study area's sampling lengths as well as lengths that were often employed in previous research. Their statistical results, which are extracted and listed in a table, include variance, mean, standard deviation, and coefficient of variation. These statistical results can now be represented and interpreted more effectively thanks to the statistical approach of examining the histograms of the data in Microsoft Excel. According to the statistical analysis of these results, three groups of composites are identified: those with short lengths (between 0.5 and 1 meters), those with long lengths (5 and 10 meters), and those with lengths that are very near to the average length of the drill samples (from 1.7 to 2 meters). These results also show that the iron resource reserves will be overestimated by short-length composites and underestimated by long-length composites. On the other hand, composites with lengths that are extremely close to the average length of the samples will result in more accurate estimations. The length of 2 meters was determined to be the composite length best suited to make an optimal estimate and an accurate calculation of the Timulike iron deposit resource reserves through a more thorough investigation of this last group of composites utilizing Microsoft Excel's conditional formatting method.