This paper is a positive contribution to the safe and cost-effective blasting of tunnels. It emphasizes the high dependence of blasting results on drilling accuracy. Attention is paid to the efficient, hazard-free drilling and blasting of burn cuts; failure in the burn cut is usually synonymous with a "frozen" round. Some advantages and limitations of water gel explosives (cf. Gelignites) are presented as are the relative merits of paper and plastic as cartridging materials. Inadequate mixing of anfo causes reductions in both the safety and efficiency of blasting. Overbreak resulting from perimeter blastholes containing anfo can be reduced significantly by continuously side initiating the charge; greater decreases in overbreak are achieved by using anfo/polystyrene mixtures. The phenomena and effects of sympathetic detonation and dynamic pressure desenitisation of explosives (especially in burn cuts) are described. Aspects of post blast fumes which are associated with the introduction of recently-developed explosives are briefly mentioned. /TRRL/

  • Corporate Authors:

    Institution of Engineers

    11 National Circuit
    Barton, A.C.T.,   Australia 
  • Authors:
    • Hagan, T N
  • Publication Date: 1978-9


  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00194039
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Monograph
  • Files: ITRD, TRIS, ATRI
  • Created Date: Jul 11 1979 12:00AM