Tunnel blast design illustrations

The following criteria govern the design of the drilling, loading and firing plan: - Cross section of tunnel 16 m 2 - Blastability Medium - Borehole diameter 37 mm - Borehole depth 3,5 m - Contour Smooth blasting Parallel cut, large diameter, area 150 cm 2 (curve Fig. 4.11 ) Number of large diameter holes 2@ 102 mm–164 cm 2 Distance between large diameter hole and first loaded hole: : a = 1.5 × 10.2 mm = 15 cm Number of holes of 37 mm diameter 47 (curve Fig. 4.13 ) Explosives per m 3 of rock (specific loading) 1,85 kg/m 3 (curve Fig. 5.1 ) Rock per round: 16 m 2 × 3.5 m = 56 m 3 Drilled meters per m 3 : (47 + 2) × 3.5/56 m 3 ) = 3,06 m/m 3 Explosives per round total: 56 m 3 × 1.85 kg/m 3 = 103,6 kg Cut/production/lifter/wall: Cartridged explosives of diameter 32 and 25 mm Contour (roof): One cartridge of 25 mm and 80 gr/m detonating cord Detonators: Millisecond (Group 3) in the cut, otherwise 1/2 — second (Group 3)