Date of Issue: May 5, 2006

Description

"Flyrock" means rock that is thrown through the air as a result of blasting. Flyrock is an integral part of blasting that needs to be properly controlled. If flyrock is uncontrolled the rocks, which can travel significant distances, pose a risk to persons involved with blasting as well as anyone else in the area of the blast. There is also the potential for damage to nearby property or equipment.

Between 2003 and 2005, there were at least five serious incidents or near misses involving flyrock. All of these incidents had the potential for very serious or fatal results. In some cases there was significant damage to property and structures.

Causes of Flyrock

The investigations of the recent incidents point to several causes:

1. blast holes loaded with excessive explosives
2. blast design omitting some design parameters, such as adequate burden
3. incomplete or poorly conducted hazard assessment prior to blasting
4. incomplete checking of hole placement and geological changes of the rock mass
5. no clear lines of responsibility and supervision for the whole blasting activity

Suggested Preventive Measures

To reduce the chance of uncontrolled flyrock, blasters should:

1. Ensure that all blast holes are loaded with the proper amount of explosives
2. Ensure that they consider all the parameters, including adequate burden, in their blast design.
3. Perform a complete hazard assessment prior to blasting.
4. Check all hole placements and look into geological changes of the rock mass.
5. Ensure that profile methods are applied where there is a potential for drill wander due to cracked ground.
6. Establish clear lines of responsibility, supervision and communication for the whole blasting activity. The blaster should talk to the driller to determine the condition of the boreholes before loading them with explosives.
7. Establish, review and enforce written safe work procedures for all blasting operations
8. Ensure that all persons associated with the blasting activity are properly trained.
9. Give careful consideration to the blast orientation (i.e. quarry face) to ensure the blast occurs in a safe direction.
10. Where unexpected events occur, determine the causes and take appropriate action.

As well, to guard against unexpected flyrock, blasters should:

1. Predetermine the danger area and clear everyone from the danger area.
2. Protect themselves and others from the threat of possible flyrock with adequate blasting shelters.

What is the law?

Blasting safety in Nova Scotia is covered in the General Blasting Regulations. These regulations require that all blasting be done only by certified blasters. In addition, these blasters must make sure that all of the regulations are observed.