1945 In the simulation utilizing a 1.8 m spacing, the following observations were made: • 1 1/2-inch Explosive Diameter: The performance regarding presplit filter generation is classified as "fair," according to the criteria established in Table 3. As shown in Figure 3, there is sufficient connectivity between the fractures generated by the 1 1/2-inch diameter to allow for the formation of a continuous fracture plane. • 1 1/4-inch Explosive Diameter: In contrast, the cracks generated by the 1 1/4-inch diameter fail to coalesce, resulting in an attenuation percentage of less than 20%. According to the classification in Table 3, this represents "Very Poor" performance. • Attenuation Efficiency: The theoretical attenuation percentage calculated through numerical modeling is 34% for the 1 1/2" diameter, while the 1 1/4" diameter yields a value of 18% (see Figure 7). Figure 14; Results obtained under intact rock conditions for packaged explosive diameters of 1 1/2" and 1 1/4", with a 1.8 m spacing and a 0.5 x 0.5 m grid. Illustration 7; Presplit filter results for 1.8 m spacing. 7. CONCLUSIONS Based on the results of this study, the following conclusions are reached: • Modeling Framework: The analysis was conducted using numerical modeling, considering a rock mass with a GSI of 60% (Hoek, 2002). This necessitated the incorporation of structural planes consistent with this specific geomechanical condition. • Study Objective: This study represents a theoretical evaluation of various presplit design scenarios, analyzing the effects of varying both the borehole diameter and the packaged explosive diameter. • Optimal Configuration: When comparing the spacing scenarios, the highest presplit attenuation efficiency was achieved with a 1.2 m spacing and a 1 1/2-inch explosive diameter, reaching 48% according to the classification in Table 3. However, this design exhibited a larger fracture radius, indicating a greater impact on the rock mass compared to the 1 1/4-inch diameter, which recorded an efficiency of 39%.
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