1. Blast Site Edge Protection
Drilling and Blasting
Toolbox Talk : 03
Blast Site Edge Protection
Information on the use of edge protection systems in the blasting area
Target Audience
Any person likely to be working in the blasting area and those supervising such operations.
Quarries Working towards a safe and healthy quarrying industry National
Joint Employers
Advisory Employees
Committee Health and Safety Executive
This publication may be freely reproduced except for advertising, endorsement or commercial purposes.
The information is current at February Please acknowledge ‘QNJAC’ as the source 
Updated September 2009

2. Blast site edge protection 1 : Introduction
Lives have been lost in the past through falls from quarry faces.
Thankfully this is now very rare mainly due to control measures introduced to prevent it.
This toolbox talk is designed to help the industry to reduce further the likelihood of these incidents.
In deciding what are the most suitable control measures for any particular circumstance, account needs to be taken of both The Quarries Regulations 1999 and the Work at Height Regulations 2005.

3. Blast site edge protection 2 : Managing the Risk
The Operator is responsible for Health and Safety on site including all drilling and blasting activities
This includes the design, construction and provision of blast site edge protection
Blast site activities include
Surveying, marking out, drilling, loading and firing
It is therefore very important to carry out a site specific risk assessment including all the personnel likely to be involved in the blasting operation
For Example
Driller, Shotfirer, Explosives Supervisor, Quarry Manager
Bulk explosive supplier, Geotechnical Consultant

4. Blast site edge protection 2 : Managing the Risk
The following topics should be considered as a minimum in a risk assessment
Prevention of personnel and equipment from falling over the edge
The site geology and stability of the face.
Access to the blast site for drill rig, delivery of stemming, explosives delivery vehicles, bulk explosive trucks and emergency vehicles.
Blast design parameters Such as spacing, burden, etc
Profiling and surveying operations
Weather conditions

5. Blast site edge protection 2 : Managing the Risk
The Work at Height hierarchy should be followed in selecting the method used:-
Collective measures should be given priority over personal protective measures. Physical barriers such as the safety bund and post and strap should be considered first
Where the use of physical barriers creates an unacceptable risk then other measures such as delineation of the danger zone or harnesses should be considered
The Quarry operator should be able to show that they have considered how a fall from an open edge will be prevented for that particular shot.

6. Blast site edge protection 3 : Protection Methods
Safety Bund
Advantages
Provides protection for people
Does not need removing before blast
Disadvantages
Can cover up bad edge conditions
A safe system of work needs to be established detailing how such bunds put in place
Requires the movement of mobile plant close to the crest

7. Blast site edge protection 3 : Protection Methods
Safety Bund
How high do the bunds need to be ?
People only on the blast area
Not less than 1m
In this case a second bund will be required behind the blast to prevent vehicles from encroaching
Vehicles operating on the blast area
A minimum of 1.5m or the radius of the largest vehicle wheel

8. Blast site edge protection 3 : Protection Methods (continued)
Post and Strap
Designed to prevent personnel from accidentally approaching the edge
Advantages
Acts as a physical barrier to prevent personnel from falling over face
Disadvantages
Barrier will not prevent machinery from falling over face
Requires a drill rig to approach the edge to drill post holes
Placing and removal of system requires personnel to approach the edge
Normally this will require the use of an additional fall prevention system
Removal of system can result in the initiation system being disturbed with the potential for misfires

9. Blast site edge protection 3 : Protection Methods (continued)
Post and Strap – Bad Practice
Only a single strap
has been used !
Worse than useless as the protection has been placed such that the face edge comes inside the protection

10. Blast site edge protection 3 : Protection Methods (continued)
Post and Strap – Good Practice
Two straps have been used
Straps are tensioned
Line of protection is positioned just in front of the first row of holes

11. Blast site edge protection 3 : Protection Methods (continued)
Stand-off Distance
In this case workers may not approach within a specified distance to an unprotected edge
The distance needs to be well delineated with some form of barrier
Good example is when used with cones and rope
This system needs to be well supervised
Advantages
No need for the drill rig to approach the bench edge
Can easily be removed before the blast
Disadvantages
Does not prevent either people or equipment from falling over face

12. Blast site edge protection 3 : Protection Methods (continued)
Example of Stand-off Distance
In the photograph this system is used on a site that employs a stand-off distance of 3m.
A cone and rope system has been used to indicate the stand-off distance from the edge of the face
Note also that in this case a bund has been positioned to prevent equipment such as bulk explosive trucks from coming on the blast area

13. Blast site edge protection 3 : Protection Methods (continued)
Fall Prevention Systems
Should only be used as a last resort
Should be installed so as to prevent personnel reaching the crest and falling over the face
Requires that personnel are also trained in emergency recovery procedures.
Many sites require the use of such system when removing the post and strap system previously described

14. Blast Site Edge Protection 4 : Key Points
Edge protection is required for all blast areas
Each blast should be separately assessed to determine suitable protection measures for that location
A single edge protection system may not be universally appropriate
If you think the edge protection is inadequate STOP WORK and inform your supervisor