Conversion of Oil Sands By-Products to Closure Landforms

The goal of this project was to collect high-level design and environmental information on oil sands mining by-products to guide their use in the construction of landforms or landform elements as part of the reclaimed post-closure mining landscape, and to highlight geotechnical and geoenvironmental issues related to the handling or long-term storage of these by-product materials. The project had three phases: (1) Data Gap Analysis – identify ‘critical’ mining by-products anticipated in the post-closure landscape and conduct a data gap analysis of the present body of knowledge concerning the geotechnical and geoenvironmental properties of these by-products; (2) ‘Adaptive Landform’ Concept Review – improve understanding of the evolution of reclaimed landforms in the post-closure landscape – how to predict this evolution and associated changes, how to design for these changes, and how to communicate these evolutionary processes to others; and (3) Landform Conversion Assessment – characterize the selected critical by-products geotechnically and geoenvironmentally, using laboratory and field data collected by mine operators, and provide considerations regarding how each by-product might be used, re-used, or stored in the reclaimed landscape.

In Phase 1, 5 tasks were completed: (1) updated list of testing requirements and protocols; (2) regional list of 25 by-products; (3) identification of critical by-products; (4) review of data on 10 critical by-products; and (5) data gap analysis – 5 critical by-products had enough information for assessment, and 5 did not. In Phase 2, landform evolution was explored through a literature review and a workshop of experts. It was recommended that oil sands operators: (1) adopt the framework of landform evolution and checklist of landform evolution processes in landform and closure plan designs and adaptive management programs; (2) prepare an overview of each process that summarizes: a) its definition, b) its timelines, and c) prediction tools and design guidance for that process; (3) conduct a workshop to identify knowledge gaps for predicting or designing for the processes and determine a path towards filling knowledge gaps and prioritize ‘key’ landform evolution processes; and (4) present these findings to internal engagement teams for awareness and discussion. In Phase 3, 12 by-products were assessed for use, re-use or storage in the reclaimed landscape. Geotechnical data were assessed based upon constructability considerations while geoenvironmental data were assessed based upon solute transport considerations.