Northwest Institute

Working towards social and ecological sustainability in Northwest British Columbia since 1996

Technical Review of the Telkwa Coal Mine Proposal


This review was conducted by Dr. Patrick Littlejohn, P.Eng., Senior Chemical/Metallurgical Engineer with Source and a Qualified Professional in BC in the area of mine water treatment and discharge planning. It provides a third party technical review of the Tenas Coal Project Environmental Assessment Certificate Application and was conducted to support the Northwest Institute during the public comment period for the Application. Download the report here.

This review was conducted with the following focus areas and questions in mind:

  1. Geochemical sampling program – are the mineral samples collected representative of coal ore, ore halo & waste rock? Was the geochemical testing program rigorous? How much selenium is present in project rock?
  2. Source control – does the Project apply appropriate Acid Rock Drainage (ARD) mitigation measures in ways that make sense and align with overall mine plan and water balance (i.e. Potentially Acid Generating (PAG) rock submergence, waste rock pile design)? What is the potential for selenium release?
  3. Site water balance – is site water management infrastructure robust and capable of handling a wide range of weather conditions (i.e. wet years, dry years, extreme weather events)?
  4. Mine contact water quality – how contaminated is mine contact water expected to be and are predictions reasonable? How sensitive are predictions to things that may be uncertain, like PAG characterization, site water balance?
  5. Water treatment approach and capacity – how is water treatment applied, and are water treatment goals achievable with the technologies describe? Is water treatment capacity sufficient? Will treatment address potential selenium contamination?
  6. Discharge location – does the project design follow BC best available technology/initial dilution zone policy?

Summary of Findings

Significant risks were identified with the Application in each of these subject areas. To summarize:

  1. The geochemical sampling program is not sufficiently robust to characterize the ML/ARD potential of the disturbed material. The proposed approach to MLARD management relies entirely on source control, which leaves no room for error in materials identification and handling. Significant risk of onset of acid rock drainage, neutral metal leaching and selenium contamination exists with the proposed project.
  2. The Application contains insufficient evidence/analysis supporting the idea that the implementation of source control is practical and can be executed under a range of climate conditions or in the context of geochemical uncertainty.
  3. The Application includes water management features that are designed to meet 1-in-10 year storm events. Discussion of variable climate conditions (i.e. climate change) are limited. Given that the project is to operate for over 20 years with a total lifespan including closure/post-closure of close to 50 years, use of shorter or less conservative design basis adds risk of impacts to the environment.
  4. Expectations of mine water quality are optimistic and do not entertain the possibility of onset of ARD if any aspect of the mine plan does not go according to plan (i.e. mishandling of PAG material, failure of source control measures, higher than expected geochemical source terms, or flushing of oxidation products prior to material submergence).
  5. Water treatment is not included in the application. Any contamination that occurs in mine contact water is proposed to be released directly to the receiving environment without treatment. This is a significant deviation from best practices in BC and represents a major risk to the downstream environment.
  6. The Application proposes site specific water quality targets that are significantly less conservative than BC’s generic guidelines using a process that does not align with BC’s policy. The Application does not include use of Best Available Technology to prevent contamination and so does not follow BC policy on initial dilution zones.

Overall, the project design is predicated on an optimistic interpretation of limited geochemical data and the ability to execute a mine waste and water management strategy with little margin for error. Modeling conducted by the proponent indicates that they expect the immediate receiving environment to be degraded with mine-borne contaminants including a 200 fold increase in selenium concentration in local creeks. The project does not follow BC policy on application of Best Available Technology to prevent contamination in the downstream environment. All of these factors mean that there is significant risk of the project having both short and long term negative impacts on water quality in the downstream environment.