Graphite One Inc. plans to develop the Graphite Creek Project, a graphite mine and mineral processing facility near Nome, Alaska. Barr completed an NI 43-101-compliant feasibility study, which incorporated data and information from other consultants, third-party laboratories, and Graphite One, and ultimately published a compliant technical report for the project. Part of Barr’s work involved designing a waste management facility (WMF) to store co-mingled tailings produced by the mill and waste rock (non-ore material) from the mine. The WMF’s primary objective is to safely store the material produced during mining operations while prioritizing progressive closure of the facility and minimizing operating and capital costs.
To support the design of the WMF, Barr completed geotechnical characterization and analysis of the site and performed material characterization for the filtered tailings produced by the pilot processing plant. Barr retained an expert seismologist consultant to perform site-specific probabilistic seismic hazard analysis (PSHA) and a deterministic seismic hazard analysis (DSHA). These analyses were based on a selected design earthquake to develop ground motion time histories for use in seismic deformation modeling.
Barr conducted a field investigation to assess and characterize foundation conditions. We performed seepage analysis, slope stability analysis, and deformation modeling using GeoStudio and FLAC to help evaluate constructability, long-term static stability conditions, consolidation processes, and seismic loading. We also performed advanced, critical state-based constitutive modeling for both static and seismic deformation modeling and liquefaction assessments. Conducting a sensitivity assessment helped us to model the potential transition of filtered tailings from unsaturated to saturated conditions and the associated impacts with respect to liquefaction susceptibility.
