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Without proper controls, working in or around any excavation is risky. It can result in cave-ins, being struck by moving machinery, slips, falls and exposure to hazardous substances. An excavation is any dug-out area of ground other than a trench, tunnel or excavated shaft. A trench is an excavation that is deeper than it is wide and a tunnel is an underground passage with an incline of 45°or less from the horizontal.

Proper planning is important when breaking ground. Many hazards can be eliminated or mitigated when identified in the planning stage before digging begins. Common hazards associated with this work include the location of the site, adjacent property, structures and people in and near the site, overhead clearance for machinery, weather conditions, ground conditions, moving machinery, slips, falls and exposure to hazardous substances.  The amount of time the trench is being used also a factor in any hazard assessment. One of the biggest risks is the potential for a cave-in. When the walls suddenly collapse, soil can quickly fill the excavated space, exerting tremendous pressure on anything in its path.

Types of Soil

The Occupational Health and Safety Regulations, 1996 [S.S., c. O-1.1, r. 1] sets out four soil types. If you are unsure about the soil type, have the soil tested. If an excavation or trench contains more than one type of soil, the soil should be classified as the soil type with the highest number.

Type 1 soil

  • is hard in consistency, very dense in compactive condition and;
  • if a standard penetration test is performed, has a standard penetration resistance of greater than 50 blows per 300mm;
  • can be penetrated only with difficulty by a small, sharp object; has a low natural moisture content and a high degree of internal strength; has no signs of water seepage; and can be excavated only by mechanical equipment.

Type 2 soil

  • is very stiff in consistency, dense in compactive condition and, if a standard penetration test is performed, has a standard penetration resistance of 30 to 50 blows per 300mm;
  • can be penetrated with moderate difficulty by a small, sharp object;
  • is difficult to excavate with hand tools;
  • has a low to medium natural moisture content and a damp appearance after it is excavated;
  • has no signs of water seepage;
  • does not include previously excavated soils.

Type 3 soil

  • is soil that is stiff to firm or compact to loose in consistency and has one or more of the following characteristics:
    • is stiff in consistency, compact in compactive condition and, if a standard penetration test is performed, has a standard penetration resistance of 10 to 29 blows per 300mm;
    • can be penetrated with moderate ease by a small, sharp object;
    • is moderately difficult to excavate with hand tools;
    • shows signs of surface cracking;
    • shows signs of localized water seepage; or
    • is previously excavated soil that does not exhibit type 4 soil characteristics.

Type 4 soil

  • is soil that that has been either previously excavated or is undisturbed soil that has any of the following characteristics:
    • is firm to very soft in consistency, loose to very loose in compactive condition and, if a standard penetration test is performed, has a standard penetration resistance of less than 10 blows per 300mm;
    • is easy to excavate with hand tools;
    • is cohesive soil that is sensitive and, on disturbance, is slightly reduced in internal strength;
    • is dry and runs easily into a well-defined conical pile;
    • has a wet appearance and runs easily or flows;
    • is granular soil below the water table, unless the soil has been dewatered;
    • exerts substantial hydraulic pressure when a support system is used.

Employer or contractor responsibilities

Employers or contractors are responsible for ensuring that all relevant legislation is followed and work done in and around trenches and excavations is done in a safe manner.

An employer or contractor must:

  • Give notice to the divison as soon as reasonably possible of any plans to:
    • dig a trench, shaft or excavate space workers may enter, that is more than 5m deep;
    • dig any tunnel that workers may enter;
  • Give notice to the division as soon as reasonably possible if there is a dangerous occurrence at the jobsite, whether or not a worker is injured. A “dangerous occurrence" would be a structural failure or collapse of a shaft, tunnel or excavation that caused the hospitalization of a worker for at least 72 hours or could have caused the death a worker. The required notice must include the:
    • names of each employer, contractor and owner at the place of employment;
    • date, time and location of the dangerous occurrence;
    • circumstances related to the dangerous occurrence; and
    • name, telephone number and fax number of the employer, contractor or owner or a person designated by the employer, contractor or owner to be contacted for additional information.
  • Locate all underground pipelines, cables and conduits where work is to be done;
  • Make sure that the locations of underground utilities are conspicuously marked before you dig using power tools or powered mobile equipment or breaking ground surface with any equipment to a depth that may contact underground utilities:
  • Expose the utilities by hand digging or another approved method, if the work disturbs the soil within 600mm or an existing pipeline, cable or conduit;
  • Support the exposed pipeline, cable or conduit to prevent any damage during backfilling and any subsequent settlement of the ground;
  • Immediately notify the owner of the pipeline, cable or conduit where there is a contact with or damage to underground utilities; and
  • Take steps to protect the health and safety of any worker at risk until the resulting unsafe condition is repaired or corrected.
  • Before excavation and trenching begin, support the structure that may be affected by excavation or trench by a temporary protective structure designed by a professional engineer.
  • Make sure that all loose material is scaled or trimmed from the sides of excavations or trenches that workers are likely to enter.
  • Make sure that equipment, spoil piles, rocks and construction materials are kept at least one metre from the edge of an excavation or trench.
  • Keep excavations or trenches free of water if workers are likely to enter them.
  • Ensure the sloping angle of spoil piles next to an excavation or trench are not at an angle steeper than one horizontal to one vertical, or 45 measured from the horizontal.
  • Check if work may affect nearby overhead power line supports, such as utility poles. If the work cannot be done without weakening these supports, contact the utility company and get permission to dig.
  • Make sure that no powered mobile equipment or vehicle is operated and that no powered mobile equipment, vehicle, or heavy load, is located near an excavation or trench where they could affect the stability of the excavation or trench’s walls.
  • Make sure that when the wall of an excavation or trench is cut back,
    • if the soil is classified as Type 1 or Type 2, the walls must be sloped to within 1.2 m of the bottom of the excavation or trench, with a slope at an angle not steeper than one horizontal to one vertical, or 45 measured from the horizontal;
    • if the soil is classified as Type 3, the walls must be sloped from the bottom of the excavation or trench, with a slope at an angle not steeper than one horizontal to one vertical, or 45 measured from the horizontal; and
    • if the soil is classified as Type 4, the walls must be sloped from the bottom of the excavation or trench, with a slope at an angle not steeper than three horizontal to one vertical, or 19 measured from the horizontal.
  • If the wall of an excavation or trench is made of sound and stable rock, other procedures may be used as long as the health and safety of workers is not at risk. 
  • When the trench is considered as a confined space, follow safety precautions that apply to confined space entry, such as monitoring and ventilation.

Temporary Protective Structures

Temporary structures may be needed in excavations, trenches, tunnels, excavated shafts or boreholes to prevent the dangerous shifting of materials or a collapse of walls supporting these spaces.  It is the employer’s or contractor’s responsibility to ensure that temporary protective structures are created, maintained and removed safely according to the legislative requirements. 

  • Artificially freezing the ground is a possible alternative to temporary protective structures if it is designed by a professional engineer and applied the engineer’s specifications and instructions.  Natural freezing is never acceptable as an alternative. 
  • To prevent material from falling in, temporary protective structures must extend at least 300mm above the walls of the excavation, trench, tunnel or excavated shaft. 
  • Design drawings and instructions must be kept at the site of the excavation, trench, tunnel, excavated shaft or borehole.

Employer or contractor responsibilities for protection against cave-ins.

Preventing Cave-ins in an Excavation

Generally workers are safest keeping a distance from walls or banks equal to the height of those walls or the depth of the excavation.

  • If workers are in an excavation that is more than 1.2m deep and must be closer to the wall or bank than the distance equal to the depth of the excavation,
    • cut back the upper portion of slope of the walls so that it follows requirements laid out for each classified soil type; or
    • install a temporary protective structure; or
    • a combination of cutting back the walls to the required slope and installing a temporary protective structure that extends at least 300mm above the base of the cut-back.
  • Temporary structures that are required in excavations more than 1.2m deep must be designed by a professional engineer and installed or removed according to professional designs.
  • When an excavation is more than 3m deep, the professional engineer must certify that the structure is safe and that it has been installed, maintained and removed according to the professional design specifications. 
  • Shoring for temporary structures in an excavation must be made of 1 structural grade spruce lumber. The required sizes are set out in Table 17 of the Appendix according to the type of soil and the depth of the excavation. Alternatively other materials that are equally strong or stronger can be used.

Preventing Cave-ins in a Trench

  • Protect workers from cave-ins, structural collapses and being struck by shoring components when shoring is installed or removed.
  • Connect pieces of shoring securely together to prevent sliding, falling, kickouts or other possible failures.
  • The maximum load allowed is no more than what the components of the shoring were designed to bear.
  • Shoring for temporary structures in an exaction must be made of 1 structural grade spruce lumber. The required sizes are set out in Table 17 of the Appendix according to the type of soil and the depth of the excavation. Alternatively other materials that are equally strong or stronger can be used.
  • As a safe way to enter and exit trenches, each trench must have ladders, stairways or ramps no more than 8 m from each worker in a trench.
  • When a worker is in a trench more than 1.2m deep,
    • cut back the upper portion of slope of the walls so that it follows requirements laid out for each classified soil type; or
    • install a temporary protective structure; or
    • combine cutting back the walls to the required slope and installing a temporary protective structure that extends at least 300mm above the base of the cut-back.
  • Station a competent worker outside trenches more than 1.2m deep to inform others about potentially unsafe conditions and to help in an emergency.
  • Ensure that a temporary protective structure in a trench more than 6m deep in Types 1, 2, or 3 soil or in a trench more than 4m deep in Type 4 soil is designed and certified as safe by a professional engineer and installed, used, maintained and dismantled according to the professional designs.

Temporary structures in excavated shafts and tunnels

  • Ensure temporary structures are appropriate for the type of soil present and prevent collapse or cave-in of the walls of the excavated shaft or tunnel.
  • Shafts more than 3m deep and all tunnels must have temporary protective structures designed and certified by a professional engineer.
  • Make sure that the temporary protective structures are installed, used, maintained and removed according to the professional design. Around each shaft or tunnel opening, install a solid or wire mesh fence at least 1m high. This fence will prevent material from falling into a shaft or tunnel opening. Gates in the fence must be substantial and at least 1m high. Keep all gates closed when workers are not using them.
  • Water must not accumulate in shafts or tunnels.  Provide suitable equipment and tools to prevent water accumulation.

Boreholes, belled areas of excavated shafts

  • If workers may be entering a borehole, casings must be designed by a professional engineer and constructed, installed, used, maintained and removed according to the professional designs.  These casings must extend 300mm above the ground so that material will not fall into the casing’s opening. 
  • Makes sure that workers are not permitted
    • to enter the belled area of an excavated shaft unless it is protected by a temporary protective structure that has been designed by a professional engineer and has been constructed, installed, used, maintained and dismantled in accordance with that design; or
    • to remain in a belled area of an excavated shaft if there are likely to be falling materials in the area. 
  • Make sure that the worker goes before or accompanies each load of excavated material to the surface.

Worker responsibilities

As a worker, you must:

  • Follow safe work procedures established by your employer.
  • Not enter trenches if they are not adequately protected from cave-ins and other risks.
  • Wear all personal protective equipment provided by the employer.
  • Conduct daily inspections on temporary structures for possible defects.
  • Be aware of all potential health and safety hazards/risks and the controls put in place to prevent them.
  • Report promptly to the supervisor any hazardous situations of equipment and work site.

Special requirements for excavations in mines

An employer or contractor must:

  • Prepare and implement open pit and underground mine designs that also outline the geometry of existing and proposed excavations. and
  • Take effective steps to control the movement of strata in all underground excavations such as supporting the ground by bolting, timbering, shotcreting or screening and sounding or scaling.  
  • Give notice to the division as soon as is reasonably possible of any dangerous occurrence including the unanticipated failure or collapse of all or any part of an excavated shaft, tunnel, trench or excavation.

Occupational Health and Safety Regulations, 1996
S.S., c. O-1.1, Reg 1

Part XVII Excavations, Trenches, Tunnels and Excavated Shafts

Section 259 Locating underground pipelines, etc.

259. (1) An employer or contractor shall accurately establish the location of all underground pipelines, cables and conduits in an area where work is to be done and shall ensure that those locations are conspicuously marked:

(a) before commencing work using power tools or powered mobile equipment on an excavation, trench, tunnel, excavated shaft or borehole; or

(b) before breaking ground surface with any equipment to a depth that may contact underground utilities.

(2) Where an operation is to be undertaken involving the disturbance of soil within 600 millimetres of an existing pipeline, cable or conduit, an employer or contractor shall ensure that the pipeline, cable or conduit is exposed by hand digging or other approved method before mechanical excavating is allowed to begin within that area.

(3) Where an operation mentioned in subsection (2) exposes a pipeline, cable or conduit, an employer or contractor shall ensure that the pipeline, cable or conduit is supported to prevent any damage during backfilling and any subsequent settlement of the ground.

(4) Where there is contact with or damage to an underground pipeline, cable or conduit, an employer or contractor shall immediately:

(a) notify the owner of the pipeline, cable or conduit that contact or damage has occurred; and

(b) take steps to protect the health and safety of any worker who may be at risk until any unsafe condition resulting from the contact or damage is repaired or corrected.

Section 260 Excavating and trenching

260. (1) An employer or contractor shall ensure that:

(a) before excavating or trenching begins, where the stability of a structure may be affected by an excavation or trench, the structure is supported by a temporary protective structure designed by a professional engineer and constructed, installed, used, maintained and dismantled in accordance with that design;

(b) all loose material is scaled or trimmed from the side of an excavation or trench where a worker is required or permitted to be present;

(c) equipment, spoil piles, rocks and construction materials are kept at least one metre from the edge of an excavation or trench;

(d) an excavation or trench that a worker may be required or permitted to enter is kept free from any accumulation of water; and

(e) the slope of a spoil pile adjacent to an excavation or trench has a slope at an angle not steeper than one horizontal to one vertical, or 45 measured from the horizontal.

(2) Subject to subsections (3) and (4), where a wall of an excavation or trench is cut back, an employer or contractor shall ensure that:

(a) in the case of type 1 or type 2 soil, the walls are sloped to within 1.2 metres of the bottom of the excavation or trench, with a slope at an angle not steeper than one horizontal to one vertical, or 45 measured from the horizontal;

(b) in the case of type 3 soil, the walls are sloped from the bottom of the excavation or trench, with a slope at an angle not steeper than one horizontal to one vertical, or 45 measured from the horizontal; and

(c) in the case of type 4 soil, the walls are sloped from the bottom of the excavation or trench, with a slope at an angle not steeper than three horizontal to one vertical, or 19 measured from the horizontal.

(3) Where an excavation or trench contains more than one type of soil, the soil must be classified as the soil type with the highest number.

(4) Subsection (2) does not apply to an excavation or trench that is cut in sound and stable rock.

(5) Where an excavation or trench is to be made in the vicinity of an overhead power line, an employer or contractor shall ensure that the work is carried out in a manner that will not reduce the original support provided for any overhead power line pole, unless permission has previously been obtained from the utility company responsible for the overhead power line.

(6) An employer or contractor shall ensure that no powered mobile equipment or vehicle is operated, and that no powered mobile equipment, vehicle or heavy load is located, near an excavation or trench so as to affect the stability of the walls of the excavation or trench.

[Sask. Reg. 6/97, s. 11]

Section 261 Temporary protective structures

261. (1) An employer or contractor shall ensure that a temporary protective structure to be used pursuant to this Part:

(a) is designed, constructed, installed, used, maintained and dismantled to provide adequate protection to a worker who is in an excavation, trench, tunnel, excavated shaft or borehole and to a worker who installs, uses, maintains or dismantles the temporary protective structure; and

(b) extends at least 300 millimetres above the wall of the excavation, trench, tunnel, excavated shaft or borehole to prevent material from falling in.

(2) An employer or contractor shall ensure that:

(a) all drawings and instructions necessary to safely construct, install, use, maintain and dismantle a temporary protective structure required pursuant to this Part are kept at the site of the excavation, trench, tunnel, excavated shaft or borehole; and

(b) where required by this Part, a professional engineer certifies that the temporary protective structure, if constructed and installed as drawn and used, maintained and dismantled as instructed, will provide adequate protection to a worker who constructs, installs, uses, maintains or dismantles the temporary protective structure.

(3) Freezing the ground by artificial means is acceptable as an alternative or partial alternative to installing a temporary protective structure in an excavation, trench, tunnel, excavated shaft or borehole if the freezing is:

(a) designed by a professional engineer to control the ground condition so as to ensure the safety of workers; and

(b) performed in accordance with the professional engineer's specifications and instructions.

(4) Natural freezing of the ground is not acceptable as an alternative or partial alternative to the installation of temporary protective structures.

Section 262 Protection against cave-in of excavations

262. (1) Where a worker is present in an excavation that is more than 1.2 metres deep and is required to be closer to the wall or bank than the distance equal to the depth of the excavation, an employer or contractor shall ensure that the worker is protected from cave- ins or sliding material by:

(a) cutting back the upper portion of the walls of the excavation in accordance with subsection 260(2);

(b) installing a temporary protective structure; or

(c) a combination of cutting back the walls to the slope specified in subsection 260(2) and installing a temporary protective structure that extends at least 300 millimetres above the base of the cut-back.

(2) Subject to subsection (3), an employer or contractor shall ensure that a temporary protective structure required by clause (1)(b) or (c) is:

(a) designed and installed using shoring made of number 1 structural grade spruce lumber having the dimensions set out in Table 17 of the Appendix for the type of soil and the depth of the excavation or made of material of equivalent or greater strength; or

(b) designed by a professional engineer and constructed, installed, used, maintained and dismantled in accordance with that design.

(3) An employer or contractor shall ensure that a temporary protective structure in an excavation more than three metres deep is designed and certified as safe by a professional engineer and installed, used, maintained and dismantled in accordance with that design.

Section 263 Protection against cave-in of trenches

263. (1) Where a worker is present in a trench that is more than 1.2 metres deep, an employer or contractor shall ensure that the worker is protected from cave-ins or sliding material by:

(a) cutting back the upper portion of the walls of the trench in accordance with subsection 260(2);

(b) installing a temporary protective structure; or

(c) a combination of cutting back the walls to the slope specified in subsection 260(2) and installing a temporary protective structure that extends at least 300 millimetres above the base of the cut-back.

(2) An employer or contractor shall ensure that a temporary protective structure required by clause (1)(b) or (c) is:

(a) designed and installed using shoring made of number 1 structural grade spruce lumber having the dimensions set out in Table 17 of the Appendix for the type of soil and the depth of the trench or made of material of equivalent or greater strength; or

(b) designed by a professional engineer and constructed, installed, used, maintained and dismantled in accordance with that design.

(3) An employer or contractor shall ensure that a temporary protective structure in a trench more than six metres deep in type 1, type 2 or type 3 soil or in a trench more than four metres deep in type 4 soil is designed and certified as safe by a professional engineer and installed, used, maintained and dismantled in accordance with that design.

(4) An employer or contractor shall ensure that:

(a) shoring is installed and removed in a manner that protects workers from cave-ins and structural collapses and from being struck by shoring components;

(b) shoring components are securely connected together to prevent sliding, falling, kickouts or other possible failure; and

(c) individual components of shoring are not subjected to loads that exceed the loads the components were designed to bear.

(5) Where a worker is in a trench that is more than 1.2 metres deep, an employer or contractor shall ensure that a competent worker is stationed on the surface to alert the worker in the trench about the development of any potentially unsafe conditions and to provide assistance in an emergency.

(6) Where a worker is required to enter a trench, an employer or contractor shall:

(a) install ladders, stairways or ramps to provide a safe means of entrance to and exit from the trench; and

(b) ensure that the ladder, stairway or ramp is located not more than eight metres from a worker working in the trench.

(7) An employer or contractor shall ensure that workers are instructed in and comply with the requirements of this section.

Section 264 Excavated shafts and tunnels

264. (1) An employer or contractor shall ensure that:

(a) during excavating, the walls of an excavated shaft or tunnel are retained by temporary protective structures that are adequate:

(i) for the type of soil; and

(ii) to prevent collapse or cave-in of the walls of the excavated shaft or tunnel;

(b) during the excavating of an excavated shaft that is three metres or more deep or of a tunnel, the walls of the shaft or tunnel are retained by temporary protective structures designed and certified by a professional engineer to be adequate for the protection of workers in the shaft or tunnel and constructed, installed, used, maintained and dismantled in accordance with that design;

(c) a solid or wire mesh fence at least one metre high, or other equally effective means of preventing material from falling into an excavated shaft or the surface opening of a tunnel, is provided around that shaft or opening; and

(d) substantial gates that are not less than one metre high are installed in every opening in a fence provided pursuant to clause (c) and the gates are kept closed except when being used.

(2) A worker who opens a gate mentioned in clause (1)(d) shall close the gate after the worker no longer has a need to keep the gate open.

(3) An employer or contractor shall provide suitable equipment to keep a tunnel or excavated shaft free from any accumulation of water.

Section 265 Boreholes, belled areas of excavated shafts

265. (1) An employer or contractor shall ensure that:

(a) a worker who is required or permitted to enter a borehole is protected by the installation of a casing that is designed by a professional engineer and constructed, installed, used, maintained and dismantled in accordance with that design; and

(b) the casing mentioned in clause (a) extends and remains at least 300 millimetres above the surface of the ground to prevent material from falling into the casing.

(2) An employer or contractor shall not require or permit a worker:

(a) to enter the belled area of an excavated shaft unless the worker is protected by a temporary protective structure that is designed by a professional engineer and constructed, installed, used, maintained and dismantled in accordance with that design; or

(b) to remain in a belled area of an excavated shaft where the worker may be exposed to falling materials.

(3) An employer or contractor shall ensure that the worker precedes or accompanies each load of excavated material to the surface.

Part XXXIII Repeal, Transitional and Coming into Force

Schedule Table 17 Excavation and Trench Shoring

[Sections 262 and 263]

Table

Trench or Excavation Depth Soil Type Braces
Uprights Width of Excavation or Trench at Brace Location Brace Spacing Wales
1.8 m to 3.6 m Up to 1.8 m Vertical Horizontal
3.0 m or less 1 50 mm x 200 mm at 1.2 m o/c 200 mm x 200 mm 150 mm x 150 mm 1.2 m *2.4 m *200 mm x 200 mm
2 50 mm x 200 mm at 1.2 m o/c 200 mm x 200 mm 150 mm x 150 mm 1.2 m *2.4 m *200 mm x 200 mm
3 50 mm x 200 mm at 10 mm gap 200 mm x 200 mm 200 mm x 200 mm 1.2 m 2.4 m 250 mm x 250 mm
4 75 mm x 200 mm at 10 mm gap 250 mm x 250 mm 200 mm x 200 mm 1.2 m 2.4 m 300 mm x 300 mm
Over 3.0 m to 4.5 m 1 50 mm x 200 mm with 10 mm gap 200 mm x 200 mm 150 mm x 150 mm 1.2 m 2.4 m 200 mm x 200 mm
2 50 mm x 200 mm with 10 mm gap 200 mm x 200 mm 200 mm x 200 mm 1.2 m 2.4 m 250 mm x 250 mm
3 50 mm x 200 mm with 10 mm gap 250 mm x 250 mm 250 mm x 250 mm 1.2 m 2.4 m 250 mm x 250 mm
Over 3.0 m to 4.0 m 4 75 mm x 200 mm with 10 mm gap 300 mm x 300 mm 300 mm x 300 mm 1.2 m 2.4 m 300 mm x 300 mm
Over 4.5 m to 6.0 m 1 50 mm x 200 mm with 10 mm gap 200 mm x 200 mm 200 mm x 200 mm 1.2 m 2.4 m 200 mm x 200 mm
2 50 mm x 200 mm with 10 mm gap 250 mm x 250 mm 250 mm x 250 mm 1.2 m 2.4 m 250 mm x 250 mm
3 50 mm x 200 mm with 10 mm gap 300 mm x 300 mm 300 mm x 300 mm 1.2 m 2.4 m 300 mm x 300 mm

* Note: for excavations and trenches to 3 m deep in soil types 1 and 2, the wales can be omitted if the braces are used at 1.2 m horizontal spacings.

Part II Notice Requirements

Section 7 New operations

7. (1) As soon as is reasonably possible, an employer, contractor or owner shall give notice to the division of the intention to:

(a) begin work at a construction site, manufacturing plant or processing plant where 10 or more workers are to be employed for six months or more;

(b) dig an excavation, a trench or an excavated shaft:

(i) that is more than five metres deep; and

(ii) that a worker will be required or permitted to enter; or

(c) dig a tunnel that a worker will be required or permitted to enter.

(2) Not later than 14 days before beginning the process, an employer, contractor or owner shall give notice to the division of the intention to begin a high risk asbestos process listed in Table 5 of the Appendix.

(3) A notice required by subsection (1) or (2) must include:

(a) the legal name and business name of the employer, contractor or owner;

(b) the location of the site, plant, process or place of employment;

(c) the mailing address of the employer, contractor or owner;

(d) the nature of the work or process to be undertaken;

(e) the number of workers to be employed;

(f) the telephone number and fax number of the employer, contractor or owner; and

(g) the estimated starting date and expected duration of the work or process.

Section 9 Dangerous occurrences

9. (1) In this section, "dangerous occurrence" means any occurrence that does not result in, but could have resulted in, a condition or circumstance set out in subsection 8(1), and includes:

(a) the structural failure or collapse of:

(i) a structure, scaffold, temporary falsework or concrete formwork; or

(ii) all or any part of an excavated shaft, tunnel, caisson, coffer dam, trench or excavation;

(b) the failure of a crane or hoist or the overturning of a crane or unit of powered mobile equipment;

(c) an accidental contact with an energized electrical conductor;

(d) the bursting of a grinding wheel;

(e) an uncontrolled spill or escape of a toxic, corrosive or explosive substance;

(f) a premature detonation or accidental detonation of explosives;

(g) the failure of an elevated or suspended platform; and

(h) the failure of an atmosphere-supplying respirator.

(2) An employer, contractor or owner shall give notice to the division as soon as is reasonably possible of any dangerous occurrence that takes place at a place of employment, whether or not a worker sustains injury.

(3) A notice required by subsection (2) must include:

(a) the name of each employer, contractor and owner at the place of employment;

(b) the date, time and location of the dangerous occurrence;

(c) the circumstances related to the dangerous occurrence; and

(d) the name, telephone number and fax number of the employer, contractor or owner or a person designated by the employer, contractor or owner to be contacted for additional information.

(4) An employer, contractor or owner shall provide each co-chairperson or the representative with a copy of the notice required by subsection (2).

Mines Regulations, 2003
R.R.S., c. O-1, r. 2

Part V General Safety Requirements

Section 34 Controlling movement of strata

34. An employer or contractor must take effective steps to control the movement of strata in all underground excavations to protect the health and safety of workers, including:

(a) if reasonably practicable, supporting the ground by bolting, timbering, shotcreting or screening; and

(b) sounding and scaling as necessary.

Part VI Design of Mines

Section 42 Design of mine

42. (1) An employer, contractor or owner must prepare and implement a mine design that:

(a) is based on sound geotechnical engineering practices;

(b) considers, so far as is reasonably practicable, the health and safety of workers;

(c) is prepared under the direction of a qualified person;

(d) consists of drawings, plans, specifications and procedures to be used in the construction and operation of the mine;

(e) takes into account the geology of the mine;

(f) assesses the ground stability of the active and proposed workings of the mine;

(g) takes into account previous occurrences of ground instability;

(h) outlines the geometry of existing and proposed excavations;

(i) specifies the ground support system to be used; and

(j) describes the mining methods to be used, including stope sequencing and blasting methods.

(2) An employer, contractor or owner must ensure that a mine design is assessed and updated under the direction of a qualified person:

(a) annually; and

(b) before any alteration is made to the mine that might significantly affect the ground stability.

Section 52 Design of mine

52. (1) An employer, contractor or owner must prepare and implement a mine design that:

(a) is based on sound geotechnical engineering practices;

(b) considers, so far as is reasonably practicable, the health and safety of workers;

(c) is prepared under the direction of a qualified person;

(d) consists of drawings, plans, specifications and procedures to be used in the construction and operation of the mine;

(e) takes into account the geology of the mine;

(f) assesses the ground stability of the active and proposed workings of the mine;

(g) takes into account previous occurrences of ground instability;

(h) outlines the geometry of existing and proposed excavations;

(i) includes a blasting design;

(j) outlines the methods to be used to control water from the strata or from any surrounding bodies of water; and

(k) includes a slope stability monitoring program.

(2) An employer, contractor or owner must ensure that a mine design is assessed and updated under the direction of a qualified person:

(a) annually; and

(b) before any alteration is made to the mine that might significantly affect the ground stability.

Part II General Notice Requirements

Section 6 Dangerous occurrences

6. (1) In this section, "dangerous occurrence" means any occurrence that does not result in, but could have resulted in, a condition or circumstance set out in subsection 8(1) of the OHS regulations, and includes:

(a) the structural failure or collapse of a structure, scaffold, temporary falsework, concrete formwork, dam or bulkhead;

(b) the unanticipated failure or collapse of all or any part of an excavated shaft, tunnel, caisson, coffer dam, trench or excavation;

(c) any equipment failure involving a hoist, sheave, hoisting rope, conveyance, shaft timbering or shaft lining;

(d) any inrush of water underground;

(e) any outbreak of fire underground;

(f) any outbreak of fire on the surface that causes structural damage to a building at the mine;

(g) any call-out of a mine rescue team;

(h) any unusual gaseous condition in a workings;

(i) any rockburst or unexpected or uncontrolled subsidence or caving-in of a workings;

(j) any failure during use of the braking or steering system of a vehicle used for the hauling or loading of ore or waste;

(k) any loss of control of any vehicle conveying workers;

(l) the failure of a crane or hoist or the overturning of a crane or unit of powered mobile equipment;

(m) an accidental contact with an energized electrical conductor;

(n) the bursting of a grinding wheel;

(o) an uncontrolled spill or escape of a toxic, corrosive or explosive substance;

(p) a premature detonation or accidental detonation of explosives;

(q) the failure of an elevated or suspended platform; and

(r) the failure of an atmosphere-supplying respirator.

(2) An employer, contractor or owner shall give notice to the division as soon as is reasonably possible of any dangerous occurrence that takes place, whether or not a worker sustains injury.

(3) A notice required by subsection (2) must include:

(a) the name of each employer, contractor and owner involved in the dangerous occurrence at the mine;

(b) the date, time and location of the dangerous occurrence;

(c) the circumstances related to the dangerous occurrence;

(d) the name, telephone number and fax number of the employer, contractor or owner or a person designated by the employer, contractor or owner to be contacted for additional information.

(4) An employer, contractor or owner shall provide each co-chairperson or the representative with a copy of the notice required by subsection (2).

(5) An employer, contractor or owner shall ensure that every dangerous occurrence is investigated and a written report prepared in accordance with section 31 of the OHS regulations.