2024 AMA Convention & Tradeshow

Cost-effective Strategy for Investigating Permafrost at Remote, Northern Mine Sites

Authors: Robin McKillop, Dave Sacco, Vincent Fricaud, and Christopher Stevens (Northern Permafrost Consulting)

Climate change is accelerating the thaw of permafrost and opening pathways for groundwater, with consequences for existing and proposed mine infrastructure. A cost-effective strategy for investigating permafrost at remote, northern mine sites is critical to sustainable mine development, operations and closure. We use illustrative examples from mine projects in Alaska, Yukon and beyond to showcase how access to a diverse suite of tools and analytical techniques allows investigations to proceed in a phased manner, taking full advantage of desktop sources of information and lightweight field equipment to keep up-front costs and footprints of disturbance to a minimum. We are able to preliminarily map permafrost and its associated thaw sensitivity based on interpretation of high-resolution aerial photography, satellite imagery, and topographic data. We use portable geophysical survey equipment (e.g., GPR, ERT) and various configurations of lightweight drills (e.g., Talon, ShockAuger) to validate and refine the mapping, collect core samples from the active layer and upper permafrost, and install ground temperature sensors (thermistors) for longer-term monitoring. For site-specific applications, we leverage various software packages (e.g., TEMP/W) to model existing and future ground temperature and permafrost conditions. We demonstrate how a phased and multi-disciplinary strategy for investigating permafrost in association with mine infrastructure provides flexibility and avoids unnecessarily costly and logistically challenging solutions.