Analysis of blasted rocks fragmentation using digital image processing (case study: limestone quarry of Abyek Cement Company)

Abstract

One of the inseparable parts of mining activities is blasting which one of its important outcomes is fragmentation. Fragmentation is the first result of blasting that is directly related to the mining costs. There are various methods for determining the degree of fragmentation which are divided into two groups, direct and indirect methods. Among direct methods, sieve analysis and, among indirect methods, observational, empirical and digital image processing methods may be referred. In this study, which dealt with the amount of fragmentation in Pir Ali limestone mine, the digital image processing method and Split Desktop software that is the most efficient software in this respect were used. Three blocks with different blast patterns were analyzed to study the fragmentation phenomenon and, ultimately, the F20, F50 and F80 and top size values for each block were obtained separately. Outputs of the Split Desktop software were obtained in tabular form as well as cumulative grain-size curves. The F80 values for the 2.5 × 2.5 m, 2 × 2.5 m, and 2.5 × 3 m patterns were approximately 65.8, 56, and 70 cm, respectively. Finally, outputs of Split Desktop were compared to the results of the Kuz-Ram experimental model. The F80 values obtained for the 2.5 × 2.5 m, 2 × 2.5 m, and 2.5 × 3 m patterns were 54.9, 43.5, and 62.03 cm, respectively, which were in close agreement with the outputs from the software. It can be concluded that the closer F80 of the blasted rocks to the crusher entrance (60 cm), reduced the production costs, which is an outcome practically realized for the 2.5 × 2.5 m pattern.