207.1 207.3(a) 207 – 1
207.1DESCRIPTION —This work is excavation of rock using controlled blasting and production blasting
to achieve a uniform face in the rock along the plane of the specified excavation back slope .
spaced and aligned blastholes to produce a uniform surface in the rock along a specified excavation back slope . Controlled blasting methods include:
plane of the specified final excavation back slope . Presplitting uses reduced blasthole spacing, diameter, and explosive charges. The initiation of blasting in the presplit blastholes precedes the initiation of the adjacent production blasthole explosives by a delay. The delay decouples the final excavate d rock face from the excavation and prevents energy from production blasts from propagating to, and dama ging, the final cut face.
and fractures in the finished rock face when there is an insufficient burden of 15 feet or less for production blasting. It is similar to presplit blasting, but without production blast holes.
controlled blastholes. Production blastholes are drilled in a pattern throughout the main excavation area adjacent to the controlled blast row. Production blastholes are detonated in a controlled delay sequence toward an open face or relief produced by blastholes firing on an earlier delay. Production blasting fragme nts the rock in the area to be excavated, to the size required for removal and placement .
207.2MATERIALS —
have not been exposed to weather. Non -electric detonators and initiating devices include, but are not limited to, all explosive materials, initiators, blasting caps, detonating cord, delays and timing devices, and all other materials and devices necessary to perform the work. While electric detonators are not allowed , electronic programmable detonators are permissible for use. Submit copies of the technical data sheets and safety data sheets for all materials to the Representative with the Blasting Plan. A ll blasting caps for any individual shot must come from one manufacturer .
207.3CONSTRUCTION —
methods cannot produce a uniform excavated surface at the spe