City of OttawaExplosivesInformation Session 2012Explotech Engineering Rene “Moose” Morin, P.Eng. Jeff Corace, P.Eng.
Presentation Schedule • Federal, Provincial and Municipal Regulations • Explosive Products • Blast Operations Overview • Blast Design • Blast Vibration and Overpressure • Hazards of Blasting • Public relations
Why Blasting? • Efficient • Reduction of Construction Time vs. Mechanical Breakers • Effective • Consistently effective in large variety of geological conditions • Economical • Cost effective method of Rock Excavation
Unfortunately….. • Blasting represents an inconvenience to day-to-day activities of neighbors. • Blasting attracts a great deal of attention from nearby occupants and homeowners. • Blasting tends to create concern in neighbors, producing an increased number of damage complaints. • Blasting requires special safeguards to be in place.
Despite the intuitive belief that sounds and vibrations from blasting operations are an indication of increased damage potential or safety concern, such is not the case.
Storage of Explosives • Governed by the Explosives Regulatory Division (ERD) of Natural Resources Canada (Federal). • Storage of explosives for mining is generally governed by the Province or Territory in question and closely follows Federal Regulations.
Storage of Explosives • Quantity/Distance charts have been established so that all explosives storage is at a safe distance from any location where people may gather, residences, roads, churches, railways, etc. • Explosives and detonators must be stored separately.
Storage of Explosives • Careful inventories must be maintained for each product in each magazine, the area around the magazine must be kept clean, as must the magazine.
Storage of Explosives on Urban Projects • On local projects, explosive and detonators are delivered and removed daily. Temporary storage can be in “Day Boxes” or more commonly, pick up trucks with separate compartments for explosives and detonators.
Storage of Explosives on Urban Projects • Regardless of the set up, storage boxes and pickup truck containers should be locked and the truck keys removed when not retrieving explosives or detonators.
Transportation of Explosives • The Department of Transportation’s Dangerous Goods Division regulates transportation of explosives and detonators.
Requirements for Transportation • No person shall handle, offer for transport or transport dangerous goods unless he/she is a trained person, or is performing those activities under the direction of a trained person. • A trained person shall have in his/her possession at all times a certificate of training for the Transportation of Dangerous Goods. • Every explosive shipment must have with it a “Shipping Document.”
Requirements for Transportation • The transportation vehicle must meet the standards of an MTO licensed mechanical safety check. • Smoking on or around the vehicle is prohibited. • A fully charged and accessible fire extinguisher will be carried. • The vehicle must be attended at all times.
Requirements for Transportation • The carrying box must be fully enclosed, lockable and used only for high explosives; if detonators are carried, an approved barrier between the high explosives and detonators is necessary. • Quantity of explosives cannot exceed 80% of the vehicle’s carrying capacity.
Provincial Regulations • In Ontario, construction projects are governed by “The Occupational Health and Safety Act and Regulations for Construction Projects”, June 2000 (Section 196 – 206 for surface blasting works). • The Ontario Standard Specification OPS120 is often incorporated into municipal and MTO specifications.
Provincial Regulations • For blasting at mines and Quarries, the MOE Model Municipal Noise Control Bylaw NPC 103 and 119 apply. • Limits ground vibrations to 12.5mm/s and overpressures to 128dBL when routinely monitored. • MOE limits are nuisance based criteria as opposed to damaged based criteria
Provincial Regulations • The Ontario Provincial Standard, OPSS 120 (April 2008) is often applied to projects in its original or modified state. • Includes requirements for designs, submissions, pre-blast inspections, monitoring, etc. • Limits vibrations to 50mm/s (>40Hz) and 20mm/s (<40Hz). No limit for overpressure. • Current City of Ottawa spec F1201 implements a modified OPSS 120
Provincial Regulations • Effective September 2004, Surface Blasting has been established as a licenced trade. However, the licence is not mandatory in the Province of Ontario
Ottawa Regulations / By-laws • Currently no blasting by-law or permit in the City (repealed in 2004) • F1011 – Addresses pre-construction inspections. Applied to City contracts. • F1201 – Use of Explosives – Amended OPS120 amended. • For private developments, blast control documentation is typically a condition of site plan approval.
Emulsions • Derive their sensitivity from the microscopic particle size of their components and tiny air voids trapped within the mixture. • Perform well in harder rocks. • Often used to prime less sensitive explosives such as ANFO. • Offers excellent water resistance
Dynamite (NG) • Typically consists of a mixture of nitroglycerine, Nitroglycol, nitrocellulose, oxidizing salts (AN) and fuel. • NG content varies from 5% to 90% • Can be water resistant • Packaged according to field application – convolute shells, spiral wound shells, plastic shells.
ANFO • Consists of AN Prill mixed with fuel oil (typically 6% fuel oil by weight). • Typically the most cost effective explosive available. • Effective in softer rocks (Limestone). • Poor water resistance. • Requires priming.
Other types of explosive • Gels • Slurries • TNT • PETN
Initiation Systems • Initiation systems are a combination of explosive devices and accessories designed to convey a signal and initiate an explosive charge from a safe distance. • Signal function can be either electric or non-electric.
Types of Initiation Systems • Electric • Non-electric Shock tube • Electronic • Detonating cord
Initiation systems • Selection of system to employ depends on: • Type of explosive • Temperature • Geology • Hydrostatic pressure • Environmental constraints
Millisecond Delay blasting • Improves rock fragmentation • Improves rock displacement • Limits vibration • Decreases blast noise • Decreases rock throw • Reduces powder factor
Millisecond Delay Blasting • For electric and non-electric shock tube systems, the delay period is pre-set inside the detonator using a pyrotechnic fuse. • For electronic detonators, the delay period is programmed on site using a computer chip inside the detonator. • Cap scatter is a problem with electric and non-electric detonators. Not a problem with electronic detonators.
Electric • Utilizes an electrical power source with circuit wiring to convey electrical energy to detonators which in turn fire and initiate the explosive. • Modern electric detonators include an internal feature to prevent electrostatic energy from accidentally initiating the detonator. • All detonators are configured with a pre-set delay period.