Hydrogeological Services for Conventional Open-Pit Oil Sands Mining Projects
Waterline specializes in the following aspects of open pit oil sands projects:
- EIAs for new oil sands projects;
- Water management projects for existing open pit projects;
- Source water development;
- Disposal well/capacity testing;
- Regulatory requirements; and
- Post-mine reclamation.
EIAs for New Open Pit Oil Sands Projects
 Preparation of an Environmental Impact Assessment (EIA) study is required to address the environmental consequences of the implementation, operation and closure/reclamation stages of oil sands open-pit mining projects. Implementing such projects requires a detailed knowledge of the local and regional hydrogeologic regime. Linkages to related disciplines such as hydrology and groundwater-surface interaction must also be recognised, assessed, and evaluated. Injection of wastewater into appropriate non-potable geological formations is a common method of disposal. Such issues, as well as identified data gaps and potential impact mitigations on the local and regional scales must be addressed in the EIA.
Existing Open Pit Oil Sands Projects
Oil sands open pit mines represent water management projects on an enormous scale. Prior to mining and throughout the operational period, large volumes of saline and potentially sour groundwater may need to be pumped, to depressurize the basal McMurray Formation, to allow open pit mining of the overlying bitumen. Such water must be treated/re-cycled for process re-use, or piped for deep well disposal, as applicable. Once the bitumen is mined, separating bitumen from the sand/fines commonly involves the use of significant volumes of water, which must be sourced, transported to point(s)-of-use, and recycled to minimize the make-up water demand. New and existing tailings impoundments also require active water management to stabilize the facilities, and to control surface runoff and to capture subsurface seepage, which may be impacted.
Source Water Development
Oil sands open-pit mining projects cannot be implemented without a secure water source that meets the quality and quantity requirements of all project phases. Historically, source water development for open pit mines in the Ft McMurray area have focused on the Athabasca River. With increased development of oil sands projects, concern continues to be raised respecting the ability of available surface water, and
groundwater resources to meet the oil sands water requirement, while not impacting the water resource at-large or existing water users. In terms of groundwater, water wells are typically constructed using engineered stainless steel wells screens or machine-perforated liners, and can include soil or bedrock completions. Industry-standard testing methods are used to establish the long-term deliverability of the wells. Groundwater monitoring programs are implemented to prevent overexploitation of the resource and to minimize the potential for impact to existing users, as specified under the project approval. Routine well maintenance programs are implemented to ensure an uninterrupted delivery of source water. New source water wells are added to ensure adequate back-up supply/capacity.
Disposal Well/Capacity Testing
 Protocols for disposal well tests are detailed in ERCB Directive 051 (formerly Guide 51). Such methodology involves step-rate injectivity tests and represents a simple and effective method of evaluating formation fracture or parting pressure, or to establish an injection regime which should not result in formation fracturing. In one method, injection rate vs. stabilized injection pressure is plotted, with the formation fracture pressure interpreted from the inflection point corresponding to a decrease in slope. Contractor equipment currently employed for injectivity tests ranges widely in terms of automation, redundancy and real-time data monitoring. Based on Waterline experience, key to the successful completion of an injection test is to ensure that downhole and equivalent wellhead pressures are accurately quantified in real-time, while maintaining strict control on injection rates. The test program should also include a provision to measure injection pressure and rates using a variety of methods to ensure redundancy and reproducibility of data collection.
Regulatory Requirements
Oil sands projects represent complex, multi-year endeavours that are subject to regulatory and permitting, respecting water resources/hydrogeology, on a variety of levels. Examples include potable groundwater testing, licensing and annual-returns reporting under the Water Act, surface water and groundwater quality monitoring programs associated with pilot and commercial plant approvals, groundwater – surface water monitoring programs specified in approvals respecting sensitive wetlands, disposal well testing and permitting, etc. With increasing pressures on potable water resources in Alberta, an increasingly knowledgeable public, and a move to improve water use efficiency, oil sands regulatory reporting requirements are expected to increase in the future.
Post-Operation/Mine Reclamation
Mature oil sands projects have immense footprints, and these projects include unique environmental and cultural challenges respecting mine closure, reclamation and abandonment. As such, environmentally acceptable and technically viable programs have to be prepared that address both the operational and post-operational phases of the projects. Long-term implications and impacts on local and regional groundwater resources have to be assessed and quantified, where possible. Additionally, at the time of mine closure, tailings impoundments contain huge volumes of water in storage. Such water must be released in a controlled manner, such that the quantity, duration and quality of the release falls within the range specified in the project approval. Groundwater monitoring and management programs are implemented to ensure that aforementioned occurs, with deviations investigated and mitigated as required.
Waterline Resources Inc. | Groundwater Resource and Environmental Consultants | Calgary, AB, Victoria, B.C., Nanaimo, B.C.
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