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Common Blast Design Pitfalls Trouble Shooting The 19th Annual Surface Mined Land Reclamation Technology Transfer Seminar Jasper, Indiana December 5 th.

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Presentation on theme: "Common Blast Design Pitfalls Trouble Shooting The 19th Annual Surface Mined Land Reclamation Technology Transfer Seminar Jasper, Indiana December 5 th."— Presentation transcript:

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2 Common Blast Design Pitfalls Trouble Shooting The 19th Annual Surface Mined Land Reclamation Technology Transfer Seminar Jasper, Indiana December 5 th & 6 th, 2005 Wm. J. Reisz

3  Improper Hole Placement holes to close to the face optimal burdens & spacings  Transient Pressures/Dynamic Shock deadpress basic blast design insufficient decking  Electronic Initiation Systems why electronics? pyrotechnic demonstration Common Blast Design Pitfalls

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5 Hole Placement

6 Spoil

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8 Optimum Burdens & Spacings  Determine Bench Parameters bench height width length hole diameter explosives type retangular 1:1.2 staggered 1:1.5

9 105’ 25’ 15’ Non-Proportional Burdens

10 105’ 105’ ÷ 4.7 = 22.3’ 82.7’ 60.4’ 38.1’ 15.8’ 105’ 16.4’ Crest burden ≈.7 X inner row burden 110’ 110’ ÷ 4.7 = 23.4’ 110’ 86.6’ 63.2’ 39.8’ 16.4’ Proportional Burdens & Spacings 153’ ÷ 6 = 25.5’ 153’ 7 holes = 6 inner hole spacings

11 Blast Design ISEE Certificate Program, Level One-Practical Blasting Fundamentals

12 Transient Pressures  Deadpress Fire at a low order Total failure of the explosive charge  Dynamic Shock Damage the initiator Destroy the booster Fire at the wrong time Sympathetic Detonation

13 Bottom FirstInsufficient Decking

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17 Bottom First  Bottom Up ↔ times borehole diameter For example: 9” dia. X 15 = 135” ÷ 12” = 11 ¼ ’  Stemming Between Decks Rule of Thumb

18 Top Deck First

19 Top First  Top Down ↔ 1 foot for every inch of borehole diameter For example: 9” dia. X 1’ = 9’ stem  Stemming Between Decks Rule of Thumb

20 Why Electronics?

21 Why Electronic Detonator Systems?  Eliminate pyrotechnic scatter poor rock fragmentation high ground vibration levels high air blast levels greater flyrock potential

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27 Why Electronic Detonator Systems?  Eliminate pyrotechnic scatter  Delay selection, site specific  Safety immunity to RF, EMI and Stray Current completely testable automated self-test and disarm features requires specific blast machine to fire

28  Eliminate pyrotechnic scatter  Delay selection, site specific  Safety  Optimized Blast Performance Why Electronic Detonator Systems? Vibration Control Flyrock Control Floor Control Wall Control Improved Cast Percentage

29  Eliminate pyrotechnic scatter  Delay selection, site specific  Safety  Autonomous Operation Optimized Blast Performance  Inventory Control Why Electronic Detonator Systems?

30 overcome poor blast design make your job easier What Electronic Detonator Systems Will Not Do

31 Comparison to pyrotechnic dets

32 Detonators Attached to Grade Stake Shock Tube 400 ms Daveytronic 400 ms

33 Comparison to pyrotechnic dets Daveytronic

34 Comparison to pyrotechnic dets

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36 Grade Stake Pyrotechnics/ms Daveytronics/ms400 Grade Stake Actual Firing Times Daveytronic/ms Pyrotechnics/ms

37 %+ 7% Avg. dev % Blast Simulation Using Actual Shock Tube Firing Times Out of Sequence Holes Poor Fragmentation Zone If we add 17ms between holes we have.... Potential FlyrockHigher Air & Ground VibrationsColumn Disruption 6ms

38 Blast Design ISEE Certificate Program, Level One-Practical Blasting Fundamentals

39 Questions or Comments?

40 Thankswww.daveytronic.com Wm. J. Reisz


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