<p>The Raglan Mine, located in Nunavik, northern Quebec, is situated in subarctic permafrost. The nickel sulphide ore bodies currently being mined are strongly deformed by parallel bedding plane shear zones and later cross-cutting fault sets. As the mine has developed deeper, it has transitioned through a 600 m thick permafrost to the underlying subpermafrost zone. Subsequently, groundwater inflow has begun to affect operations and site water management; previously, the groundwater was used in operations, and no surface discharge was required. A major safety issue is intersecting inflows of up to 600 psi while drilling, as well as icing on the ramps during winter due to cold air ventilation. More importantly, as with all northern mines, discharge limits based on environmental permits pose operating restrictions if clean operational water is mixed with natural, saline groundwater inflow or the concentrated calcium chloride drilling fluid (water sourced from a nearby lake) needed to drill in the frozen ground. Due to the mixing of clean surface water with higher salinity groundwater and drilling fluids, water pumped from the mine has become a serious operating issue. To assess potential long term groundwater inflow rates and volumes, an assessment of inflow risk was carried out to inform mine design, planning, and the operational water balance necessary for future discharge management. A program of water sampling, permeability testing, hydraulic head pressure monitoring, and cross-hole flow testing was carried out to determine if the unfrozen ground (basal cryopeg and subpermafrost) system was connected to surface recharge via open taliks. These taliks can form under lakes developed along structural trends and can be open to depth (subpermafrost) and even through the base of the permafrost zone. The alternative inflow source is from an isolated subpermafrost zone and limited to rock mass storage capacity and could therefore be more easily depressurized and drained, due to limited recharge, as development progresses and inflow is mitigated. Vibrating wire piezometers were installed to monitor pressures as subsequent drilling and drainage progressed, to assess the effects on storage and potential for recharge. Structural modelling was used to target the drilling and later to provide risk mapping and mitigation planning for ongoing development. Studies to date indicate negligible recharge from the surface and so attention can be turned to depressurizing and draining new sections of the mine prior to their development. This permits further study aimed at understanding the significance of the structural features to be separated into specific groups or classes, and then ranked according to potential inflow risk and expected inflow volumes.</p>