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Package # VB-S-C-2019-16 QBE Nomination Closing Date
Title Dam Safety Tender Issue Date TBA
    Bid Closing Date TBA

For more information contact: Dwayne Chiasson
709-896-6426
709-752-3459
click here to send email

Contract Scope

As part of the development of the Voisey’s Bay Mine facilities, Vale Newfoundland and Labrador constructed the following impoundment facilities:

  • Headwater Pond (HP – completed in 2005)
    • Dams H1 and H2

  • North Sedimentation Pond (NSP – completed in 2005)
  • South Sedimentation Pond (SSP – completed in 2005)
  • East Diversion Dam (EDD – completed in 2004)
  • Mine Water Surge Pond (MWSP – completed in 2005)
  • Plant Site Sedimentation Pond A (SPA – completed in 2005)
  • Plant Site Sedimentation Pond B (SPB – completed in 2005)
  • Port Site Sedimentation Pond (PSSP – completed in 2004)

In order to comply with regulatory requirements as well as Vale internal policies on dam safety, an annual dam safety inspection (DSI) of impoundment facilities is required to be completed. The most recent Annual DSI, carried out by Aivek Stantec Limited Partnership, took place in August 2018.

Detailed Scope of Work to be performed by the Contractor shall include the following:

    1. To be performed a registered professional engineer in the Province of Newfoundland and Labrador and must have demonstrated knowledge and experience relating to design, construction, performance analysis, and operation of dams and tailings facilities. Along with extensive knowledge of the Canadian Dam Association’s (CDA) Dam Safety Guidelines.   

    2. The DSI shall encompass visual inspections of containment and control structures and include field inspection forms to be completed for each structure.  Photographs are essential to record the site conditions as well as document issues noted in the field inspection forms.  DSI reports are to address the apparent stability and condition of the containment and control structures and serve as a record of the site visit.

    3. The following activities shall be completed during the DSI:

      1. Visual site inspection, with emphasis on the nature, extent and condition of the contained material(s) and downstream environment;

      2. Walk-over inspection of the dams, including their crests, slopes, abutments and toe areas, with emphasis on the visible signs of change around the embankments, foundations, and abutments, which could be indicative of the stability and potential risk of instability (e.g., depressions, cracking, deformation, surface erosion, freeboard, and signs of past flooding, overtopping, internal erosion, piping, sand boils, instability, and the like) of the dam;

      3. Visual inspection of the appurtenant structures for their conditions, functionality and, where possible, adequacy; and,

      4. Digital photography of typical and significant features.  All photographs shall be geo-tagged for future reference.

         

    4. The DSI shall document:

      1. Apparent visual stability indicators.

      2. Pond levels, observed freeboard and design freeboard.

      3. Review of installed instrumentation and condition assessment. 

      4. Review of instrumentation data collected since the last DSI and commentary on recent and long term trends. 

      5. Crest conditions such as cracking, settlement, erosion, other movement and crest vegetation

      6. Downstream slope and toe area conditions such as erosion, settlement, bulging, sloughing, slope protection, slope vegetation, animal burrows and seepage. 

      7. Upstream slope and tailings surface conditions such as beach length, sinkholes, settlement, bulging, sloughing, slope protection, slope vegetation, animal burrows, sinkholes and tailings surface. 

      8. Other conditions that appear unusual and/or that could indicate stability concerns but not listed above.

      9. Provide a detailed list of recommendation/action list.