2023-10-03_REVISION - M1977344 (5)

Home Browse Search

Procedures Regarding Blast Implementation Factors To Reduce Air Overpressure Factor Procedure Drilling Accuracy Ensure good control over drilling so that the planned and spacing are those actually achieved by the driller. Good drilling control will also help to reduce the subgrade drilling, and may make it possible to reduce the total charge per hole. Preblast Inspection  Review the drill logs for the borehole conditions and drilling accuracy. The drill penetration rate will identify clay-filled seams, highly fractured zones or other zones of weakness.  Check the free faces for excessive fracturing from back break and the presence of mud seams or voids. Load the front row or boreholes according to maintain sufficient burdens to minimize the potential generation of gas release or excessive throw.  Ensure that design burdens are maintained for the entire length of the borehole. Check each borehole for incline and drift prior to loading. Loading  Load boreholes properly according to the information provided on the drill log. Borehole irregularities that may cause overloading include fracture zones, rubble zones, voids and caverns.  Deck through all fracture zones and voids to avoid overloading boreholes. Stemming  Use sufficient stemming commensurate with the burden to eliminate blowouts at the hole collar and generation of a stemming release pulse. The stemming length should be at least 0.7 times the burden.  Use competent stemming material appropriate for the drill hole diameter. Stemming material with good size and angularity promotes high-friction sidewall forces that will withstand detonation pressures and will resist ejection. Fine stemming (dust) or light weight stemming materials do not bind or lock well are more likely to be eject. Expose detonation cord Cover exposed detonation cord trunk lines when blasting near structures and consider using non- detonation cord initiation systems. Weather Condition  Schedule blasting to avoid adverse conditions. Use the internet or contact or contact local airports to get up-to date information.  To avoid the temperature inversions that may be present on windless mornings, schedule blasting in the afternoon when inversions are least like to persist.  When wind directions are unfavorable, if convenient, delay blasting until the wind direction is away from structures or the wind velocities decrease. Quality Control Review the quality control procedures to ensure that the blast plan is properly implemented. Table 9. Procedures regarding blast implementation factors to Reduce air overpressure. 5.4 Description of monitoring systems to be used and where to be set up Ground Vibrations and Air Over Pressure. For monitoring Ground Vibrations and Air Overpressure, the Quarry will utilize seismographs: “Blasting seismographs are equipped to monitor ground vibration and air over pressure. Fly Rock and Blasting Evaluation Holcim will film all the blasts with the objective/purpose of identifying potential flyrock and to evaluate the blasting events. 5.5 Blasting protocol/procedure In the Appendix 1 is the SOP for blasting in the Bear Creek Quarry will to the Red Creek Quarry.