Underground construction

Scope

Underground construction applies to the construction of underground tunnels, shafts, chambers, and passageways. it also applies to cut-and-cover excavations which are both

Regulatory citations

• 29 CFR 1926.800 — Underground construction.

Key definitions

• Tunnel: An excavation beneath the surface of the ground, the longer axis of which makes an angle not greater than 20 degrees to the horizontal.
• Shaft: A:
  • Passage made from the surface of the ground to a point underground, the longer axis of which makes an angle greater than 20 degrees to the horizontal; or
  • Pit in which there are employees, and it is foreseeable that they may enter (or do enter) the horizontal excavation; or
  • Pit that has typical underground construction hazards and is connected to a horizontal excavation.

Summary of requirements

In general, the standard requires covered employers to:

• Provide and maintain safe means of access and egress to work areas so that employees are protected from being struck by excavators, haulage machines, trains, and other mobile equipment.
• Control access to all openings to prevent unauthorized entry underground. Make sure unused chutes, manways, or other openings are covered, bulkheaded, or fenced off, and posted with warning signs indicating “Keep Out” or similar language. Completed or unused sections of the underground facility shall be barricaded.
• Maintain a check-in/check-out procedure that will ensure that aboveground personnel can determine an accurate count of the number of persons underground in the event of an emergency.
• Train employees to recognize and respond to hazards. Training should be tailored to the specific requirements of the jobsite and include any unique issues or requirements. Include the following topics in the training:
  • Air monitoring and ventilation
  • Illumination
  • Communications
  • Flood control
  • Personal protective equipment
  • Emergency procedures, including evacuation plans
  • Check-in/check-out procedures
  • Explosives
  • Fire prevention and protection
  • Mechanical equipment
• Inform oncoming shifts of any hazardous occurrences or conditions that have affected or might affect employee safety.
• When natural unassisted voice communication is ineffective, provide a power-assisted means of voice communication between the work face, the bottom of the shaft, and the surface.
• Provide the emergency provisions in 1926.800(g).