The Steenbras dam inspection project - men underground.

The Steenbras dam inspection project is one of the most difficult access work scopes to perform in the industry, due to its remote location, deep access points and limited securing locations. 

Steenbras Dam Inspection Conditions

  • Access to the site is through the use of SIMOPS techniques, integrating rope access and diving teams. 
  • Rope Access teams utilise inspection buggies with emergency response and breathing gas systems onboard for insertion into the tunnel terrains. 
  • OSC Marine is proud to have completed this work scope for the client over the last 15 years and continues to perform it with a 100% safety record.

Steenbas dam inspection rope access

Scope of the dam inspection

The work included the underwater internal and external Close Visual inspection of the storage dam water,
intake tower and pipelines including the pipe inner and outer diameter, gates and trash racks.

Steenbras dam inspection plan of dam interior

The penstock Concrete condition inspection:

  • 1064m length inclined Penstock.
  • 3.5 to 4 meter diameter concrete pipe.

Technical workscopes include:

  • Visual inspection of Penstock Concrete condition – 150m vertical height Penstock (30m surge tank and 120m fall), concrete pipe 5 meter diameter.
  • Visual and Ultrasonic Thickness measurement inspection of 491m Steel Penstock pipe thickness, (scanned for weld integrity and visual inspection for corrosion).
  • Visual and Ultrasonic Thickness measurement inspection of 4 x Draft tubes 10 meter long and 4 meters in diameter.
  • Visual inspection of embedder gates.

Steenbras dam inspection open entrance


A critical process for the selection of contractors in these types of workscopes is their safety management system and the strength of the procedures, processes and engineering capabilities in executing the work.  As such your ideal contractor will have a robust safety management system with good feedback loops and lessons learnt from industry and internal feedback, as it ensures a constantly learning organisation that applies this information to its risk reduction models.

OSC Marine has continued to focus on reducing risks in all of its value add services and perform to ensure clients achieve a Zero harm worksite.

Is your worksite due for an inspection? Get in touch!