2018-01-18_REVISION - M1977219 (4)

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BLAST DESIGN AND LAYOUT After the area is deemed satisfactory for layout, measurements are taken of the surface area dimensions of the proposed blast area desired and of the thickness and types of material and if there is a free face existing. The quarry manager, in consultation with the qualified blasting contractor, will design an appropriate drill pattern to ensure safe and efficient production in each area of the quarry.This includes the burden and spacing design, hole depth, number of holes, explosive densities, initiation sequencing pattern, stemming and other factors included in general blasting practice. All owned and non-owned structures are located and the distance to these structures is measured and recorded. The following is the blasting design used mostly in the past and will be used in upcoming blast unless the parameters change. Note that thicknesses of the subsurface geological strata do vary which require different hole patterns and/or different drill hole sizes. The thickness of the sandstone structure that will be shot typically varies from 11 ft to 25 ft. and the clay(if it is of a hardness needing to be shot)varies from 4 ft.to 15 ft. Note that the sandstone thickness can exceed 25 feet in which case the sandstone will be benched and will necessitate a double shot. The nearest non-owned structure is currently more than 1,1850 ft from the existing blasting area. Typical blast design parameters Hole diameter=3 W Pattern=Sx8 or W or tighter(depending on depths—shallower depths would require a tighter pattern) Primers=200 gram and 350 gram cast booster Initiation=non electric shock tube Bulk explosive used=anfo or titan emulsion at 1.05 g/cc final density(when the explosives are loaded into the hole, the blaster will monitor the rise of the explosive column with a tape measure and stop the loading when the desired stemming height is reached. This is done on every hole loaded.) Timing=25ms from hole to hole and 42ms to 84ms from row to row Stemming=crushed stone from the top of the explosive to the surface, typically 5 ft to 8 ft. The pattern is laid out on the ground by the blaster and the holes are drilled to the depth as determined by the thickness of the rock structure.The holes are protected with a hole plug so that no loss to the depth occurs until the day of blasting. Once the pattern is drilled, the blast is scheduled. DAY OF BLASTING PROCEDURE IN REGARD TO NOTIFICATION, SEISMIGRAPH PLACEMENT AND SHOT GUARDING 4