OFFICIAL Figure 17 - Vibration model from signature holes (Antas 2) Based on validation outcomes, the A3N pit was segmented according to distance to the administrative area, as shown in Figure 2. The data demonstrated that achieving the required control and quality necessitated reducing blasthole diameter from 5.5 in to 4.5 in. In closer zones (Sectors I and II), bench height was reduced from 10 m to 5 m to respect MIC limits needed to control vibration at the nearby administrative area and the water dam. A summary of initial drill‑and‑blast parameters for each A3N sector is presented in Table 1. Figure 18 - Zoning map by stand‑off Table 6 - Initial drill‑and‑blast parameters by sector Sector I II III IV Diameter (in) Cust om 4 ½” 4 ½” 4 ½” Burden (m) 2.2 3.0 3.5 Spacing (m) 2.6 3.6 4.2 Stemming (m) 4.0 4.0 3.5 Bench Height (m) 5.0 10. 0 10. 0 MIC (kg) 18. 0 65. 0 89. 0 Powder Factor (kg/t) 0.2 26 0.2 23 0.2 23 y = 323.75x-1.446 R² = 0.8687 y = 523.35x-1.446 R² = 1 1.00 10.00 100.00 1.00 10.00 100.00 Vibration (mm/s) Scale Distance Vibration Regression 95% Prediction Mean Vibration Regression 95% Prediction
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