# Blasting Fragmentation Study Using 3D Image Analysis of a Hard Rock Mine
## 3 Results and Discussion
Despite the small differences in each of the blasting designs, some deviations could be accounted for, such as the drilling operating conditions [8], explosive energy control [8; 9; 10], geomechanical characteristics of the rock massif [10], experimental errors of the image sampler, errors in the delineation of the rock limits and, consequently, of the size of the fragments, and errors of the FMAI algorithm. The distributions presented in Figure 5 correspond to the validation and difference between the average sizes obtained in the determining conditions via Kuz-Ram analysis (mathematical model), and the physical analysis obtained at the place where the events were held (obtained via MMpro). It is possible to observe through the graph analyzed that despite the Kuz-Ram model being widely used in most bibliographies, this method presents a certain delimitation, making visible the inability to demonstrate the number of fine particles present in the system. In addition, the range delimited to observe the fragmentation of the grains corresponds to the granulometry to be destined for the crusher, represented in the range between 150 mm and 1200 mm. The interesting thing about checking the minimum range is related to the percentage of passers-by present in the system, and this range will be differentiated according to the blasting tests carried out. The MMPro results showed that the material was well fragmented, with an average percentage of fragments passing through 150 mm: 69.70% for Tests 1-3; 66.20% for Test 4; and 56.4% for the conventional blasting test. Regarding the maximum sizes measured, the existence of blocks larger than 1200 mm was observed, with the exception of Test 3, where secondary mechanical blasting was indicated. As observed, the equipment detected a large amount of fines, thus making it necessary to adapt the Kuz-Ram formula, so that this material was correctly detected after fragmentation. As the ideal option after detonation is to present homogeneity between the grains and a finer range, facilitating the crushing operation, the ideal range for this to occur in is adherent to the range of 150-1200 mm. When checking the granulometric curves as a whole in Figure 5, it is possible to observe the decrease in granulometry as the tests are applied. \begin{table}
\begin{tabular}{l l c c c c c} \hline  & \multicolumn{5}{c}{**Tests**} \\ \cline{3-6}  & **Parameter** & **1** & **2** & **3** & **4** & **Conventional** \\ \hline n & Kuz–Ram model & 1.37 & 1.58 & 1.56 & 1.54 & 1.69 \\  & PortaMetrics & 0.48 & 0.61 & 0.51 & 0.52 & 0.36 \\ \(X_{c}\) (mm) & Kuz–Ram model & 331.46 & 281.44 & 269.19 & 335.72 & 419.48 \\  & PortaMetrics & 125.86 & 111.00 & 82.83 & 134.00 & 194.92 \\ \(X_{50}\) (mm) & Kuz–Ram model & 253.44 & 223.28 & 212.73 & 264.52 & 337.45 \\  & PortaMetrics & 60.29 & 61.91 & 47.08 & 74.00 & 114.42 \\ \(X_{80}\) (mm) & Kuz–Ram model & 469.19 & 379.80 & 365.14 & 457.12 & 556.01 \\  & PortaMetrics & 341.29 & 242.82 & 186.00 & 304.76 & 398.08 \\ \(X_{100}\) (mm) & Kuz–Ram model & 1775.00 & 1198.00 & 1175.00 & 1492.00 & 1637.00 \\  & PortaMetrics & 1530.00 & 1319.36 & 686.33 & 1421.86 & 1252.08 \\ \hline \end{tabular}
\end{table} 
Table 5: Parameters obtained using the Kuz–Ram model and the PortaMetrics platform. When checking each test, it is verified that as the dismantling operations are configured, it is possible to obtain finer grain sizes, with a considerable gap between the Kuz-Ram curves and those generated via the grain size analysis of the equipment, checking the accuracy of the equipment. It is possible to observe that the equipment makes more superficial records and analyses of the blasting, with it not being possible to validate non-visible and overlapping particles. In order for this to have more conclusive apparent results, it is recommended to use the equipment per shell to be moved for transport, thus resulting in more accurate analyses.