Systematic Drilling and Blasting for Surface Excavations Part 8 potx

... w2 h0" alt="" EM iiiO-2- 380 0 i Mar 72 Table 5-3. Some Typical Hole Spacings and Diameters, Charge Concentrations, and Burdens for Smooth Blasting (after Langefors and Kihlstr6m14) Drill Hole Charge ... the bottom and for close hole spac- ing should be much less. (2) Relation to Main Blast. Presplitting and primary blasting are sometimes performed in one operation with the...

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... heav- ing effect for loosening and moving material. (2) Presplit blasting for a finished rock surface may be more difficult in highly fractured rock depending partly on the nature and atti- tude ... compressive and tensile strengths for a selected group of rocks with divergent properties. (2) Fig. 6-2 is an empirical chart useful for estimating blasthole spacing and size...

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... Introduction. a. A necessary part of all blasting operations is the estimation of potential damage to nearby surface and underground structures and to local rock surfaces that are to remain in ... be made. c. Methods and techniques for preventing damage by cent rolling the amount of airblast, ground vibration, flyrock, and cracking are gen- erally known and should be made a...

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... Specifying and Prohibiting Certain Practices Requiring Gradation Ranges in Blasted Rock Vibration and Damage Control 8- 2e 8- 2f 8- 2g 8- 3 8- 3 8- 4 8- 2h 8- 2i 8- 4 8- 4 8- 2j 8- 4 8- 2k 8- 21 8- 4 8- 7 A-1 B-1 Appendix ... 3b 7-3C 7-3d 7-3e 7-4 8- i 8- la 8- lb 8- 2 8- 2a 8- 2b 8- 2c 8- 2d 6-7 6 -8 6-9 ;:;1 6-i2 6-i2 6-i3 6-13 6- i4 6- i4 6-i5 6-i6 7-i 7-1 7...

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... antici- pated for the future. The drilling and blasting manual for surface exca- vations is the first of this series. Selected references that describe drilling and blasting procedures and results ... 53,300 3,550 15 Basalt 9 ,80 0 730 i3 Basalt 26,500 1,990 i3 Basalt 40 ,80 0 4,020 io Gabbro 29,600 2,150 14 Gabbro 25,050 i,8i0 14 Granite 24,350 i, 780 i4 Granite 22,000 i,...

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... Fair 129 40 4.0 10,000 Fair Fair f35 35 1.0 9 ,80 0 Fair Fair 14i 30 0.9 9,400 Poor Fair 153 25 0.9 8, 800 Poor Fair 163 20 0 .8 8,300 Poor Fair 174 Low-Density Ammonia Dynamite, Low-Velocity Series 50 1.2 8, i O0 Fair Fair i20 45 i.i 7 ,80 0 Poor Fair 129 40 ... CIlln Semigelatin *-SMG I I I 1 I I 1 10 20 30 40 50 60 70 80 CARTRIDGE STRENGTH, percent Fig. 3-5. Average confined velocity...

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... largely replaced dynamites and gelatins in bench blasting. Denser slurry blasting agents are supplanting dynamite and gelatin and dry blasting agents. 3-16 E,M ili O-2- 380 0 i Mar 72 . excavation blasting in ... nitrate 57.3 46.2 37.5 25.1 15.2 Ammonium nitrate ii .8 25. i 31.4 43.1 50.3 Carbonaceous fuel io.z 8. 8 9.2 10.0 8. 6 Sulfur 6.7 5.4 3.6 3.4 i.6 Antacid 1.2 i.i...

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... O-2- 380 0 i Mar 72 SOFT ROCK BIT -FOR CLAY, SHALE, SALT, GYPSUM, CHALK, AN HYORITE, AND MEDIUM LIME ROCK. MEDIUM ROCK BIT - FOR LIME- STONE, DOLOMITE, HARD SHALE, AND AN HYDRITE. HARD ROCK BIT - FOR ... The marked insensitivity to external shock and friction makes a detonating fuse ideal for both down lines and trunk lines for primary blasting. Since the blasting cap need...

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... iiiO-2- 380 0 I 1 Mar 72 CWPTER,5. BASIC SURFACE BMTING TECHNIQUES 5-1. Introduction. a. Rock blasting may be conducted for removal of rock, for con- trol of excavated rock surfaces, and for control ... techniques used for surface excavations. Information was obtained from CE District offices and projects supplemented in less familiar procedures by references 8 and 14....

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... retain gases and reduce noise and flyrock. Table 5-1. Charge Concentration of Inclined Holes (i) for Single-Row Bench Blasting for Fragmentation with Respect to Various Burdens and Hole Diameters ... ft 1 0.42 0.17 2.i 3 .8 2 4.7 0.7 17 7 .8 3 3 .8 1.5 57 ii.5 4 6.7 2.7 130 15.5 5 10.5 4“ 260 19.5 6 15 6 440 23 7 20 8 700 27 8 27 il i,ioo 3i 9 34 13 4,500 35 Note: Values ar...

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