Mining Publication: A Hydrodynamics-Based Approach for Predicting the Blast Damage Zone in Drifting as Demonstrated Using Concrete Block Data

• Blasting
• Data analysis
• Roof falls

Rock falls involving a relatively small amount of material are a leading cause of injuries in underground mines in the United States. A contributing factor is unwanted blast damage and over-break. A goal of the United States National Institute for Occupational Safety and Health is to reduce the number of ground fall-related accidents by improving drift driving practices through the introduction of perimeter control blast designs. This paper presents a blast design technique based on a hydrodynamic method. Using commonly available explosive and geometry data, the theoretical particle velocity is calculated as a function of distance away from a cylindrical charge. A calibration factor is introduced to account for actual conditions by comparing the predicted values to a set of field data. The calibrated curve can then be applied for design. The paper introduces modifications to account for different explosives from those used in a calibration test. The application of the approach is demonstrated with respect to a data set from a large-scale concrete block test.