Mining Publication: Application of the NIOSH-Modified Holmberg-Persson Approach to Perimeter Blast Design
Perimeter control blasting is common in civil construction projects but not as common in mining. A poorly designed and executed underground mine development blast design can result in unwanted wall rock damage. This damage increases the risk of rock falls and injury. With the availability of good drilling equipment, it is a simple matter to add the few extra holes needed to change conventional drifting into drifting with perimeter control. In the 1970's, Holmberg and Persson (H-P) introduced the Swedish approach to contour blasting and it has found wide acceptance due to the logical basis and ease of application. An error in the mathematics of the H-P approach was discovered in 2002 and use has fallen into question. This paper presents a modification which corrects the mathematical error. The NIOSH-modified H-P design curves are basically identical to the original ones in the far field but with some significant differences in the near field. The application of the curves remains the same. The determination of the required site constants and the construction of the design curves are demonstrated with respect to data collected at the Stillwater mine, Nye, Montana.