Nahanni Construction was hired by Parsons Inc. to complete a vacuum enhanced dewatering trial program at Giant Mine in Yellowknife, NT. The project aimed to collect information for future tailings dewatering during site closure, specifically tailings cover installation in support of broader remediation activities at Giant Mine. Nahanni was responsible for providing all labor, materials, equipment, tools, power, operations, monitoring and services necessary to complete the program. The project required continuous control of water during the dewatering operation throughout the 28-day trial program. Nahanni also had to put measures in place to prevent the erosion of existing tailings surface outside of the dewatering trial area.

Scope of Services:

  • Ground surface preparation, provision of survey, surface water management, installation and operation of dewatering trial system, installation of instrumentation for groundwater level monitoring, monitoring of groundwater levels and tailings moisture conditions during the dewatering and testing period.

Fast Facts:

  • The project included drilling and installation of 84 wells, Installation of 7 standpipe piezometer and installation of 45 vibrating wire piezometers and 9 data loggers and cables to record groundwater levels
  • Nahanni had an excellent overall safety record and was commended by the client for their safety culture throughout the entire project.

Challenges and how Nahanni Helped:

  • One of the key aspects that required thoughtful management and preparation related to working on a site of known Arsenic contamination.
  • Tailings and road surfaces required dust control, contaminated water needed to be managed on site and considerations to ensure this was done within the appropriate best practices and regulations required good planning, training, and execution. The site is also home to numerous abandoned buildings and debris piles; some of which are contaminated with hazardous materials including arsenic and asbestos.
  • To meet the needs of this complex project and to ensure the safety and protection of our workforce Nahanni worked to implement comprehensive training and safety programing for all crew on site.
  • Other challenges included ensuring appropriate sequencing and interfacing with other activities on a busy mine remediation site and ensuring good communication with other site contractors and personnel.