HighVale Mine

Geotechnical Challenges & Construction Mitigation

  • Weak displaced soils at base of valley
    • Toeberm construction & aggregate buttresses installed
  • Borrow area –High Moisture Content
    • Soil conditioning, selective backfill , achieved all compaction specs
  • Unexpected springs encountered
    • Constructed French Drains
  • Valley slope movement due to Ancient failure-200m wide
    • Emergency placement of buttress to slow movement
  • Slope stability of both sides of ravine
    • Raised invert elevations 5m to avoid area
  • Slope stability—Ground movement
    • Excavation, culvert installation & backfill completed in panels
  • Monitoring movement
    • Instrumentation installed and raised during 30m of backfill depth
  • Backfill during winter conditions
    • Material kept live from borrow– achieved all compaction specs

Project Statistics:

  • Location: Highvale Mine, Seba Beach AB
  • Value: $13 M+
  • Client: SunHills Mining (TransAlta)
  • Our Services:
    • Salvage of topsoil
    • Pond construction and drainage
    • Excavation and Culvert
    • Haul road and ditch construction

Sureway’s Role:

In 2018 Sureway was awarded the contract for the development of a new mine expansion area, Pit 09. Sureway completed the tree clearing for this expansion in 2017.
Work scope included reclamation salvage of topsoil and peat, drainage establishment including ditches, berms, and ponds, haul road construction, and original box cut development. The key challenge was the installation and backfill of 2 large diameter CSP primary water culverts through an environmentally sensitive ravine environment that had many complex geotechnical challenges (see next page). This is the largest 2000mm culvert installation and deepest buried of this type of culvert in Alberta.

 

Scope of Work:

  • 325,000 m3 – Topsoil stripping
  • 370,000 m3 – Pond construction & drainage
  • 4.3 km – Ditches
  • 712 lm – 2000 mm diameter culvert—2 X 356m long
  • 4km – Haul Road Construction
  • 1,300,000 m3 – Original Boxcut excavation
  • 650,000 m3 – Ravine / culvert backfill—over 30m of culvert cover
  • 100,000 m3 – Unsuitable Ravine excavation