Holes for blasting must be as large as possible, but the economic limitation is that large holes need heavier equipment. In Sweden, the largest hole diameter is about 150 mm. Equipment for this can produce up to 1.5 M tons annually. Ground vibrations impose a limitation; to reduce these, the amount of explosive per interval must be cut etc, which increases costs. Equipment for 100 mm holes is being developed. Secondary blasting is possible for boulders but this is expensive, and falling weights are employed. Loading is by excavator or loader; excavators are expensive but cheap to run, the inverse being true for loaders. Tyre wear is a serious problem when loaders are used. Hauling from face to crusher is by tippers; usual size is 20 tons. The drawback of large units are the production holdups on breakdown, and buffer stores must be created. In crushing and screening, number of units should be low; reliable performance data must be available. Easy dust encapsulation is important. Dust extraction consumes 10% of total energy. To avoid segregation in storage dumps, sizes should be kept separate and proportioned prior to delivery. Crusher plant is very expensive. Sophisticated plants producing excellent products at excessive prices are no solution. /TRRL/

  • Corporate Authors:

    Svenska Vagforeningen

    Fridhemsgatan 15
    11240 Stockholm K,   Sweden 
  • Authors:
    • Bojesson, B
  • Publication Date: 1975


  • Swedish

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00132234
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • Files: ITRD, TRIS
  • Created Date: Jun 23 1976 12:00AM