Project: Challenges

In order to prevent and/or minimize the risk to human health and the environment, the recommended closure and remediation plan for the Faro Mine Complex will address several major issues resulting from historic mining activities at the site.

Contamination of Water

Metals such as zinc and lead occur naturally in the rocks around Faro. Things like rain and wind can release these metals from the rock through the weathering process. Before the mine opened, weathering was slow and the naturally released metals had no serious effect on the plants and animals in the area.

Because of almost 30 years of mining activities, there are now approximately 70 million tonnes of tailings and 376 million tonnes of waste rock located at the Faro Mine Complex. These materials have the potential for generating acid and releasing metals into the aquatic environment. In addition, certain bacteria thrive on energy stored in rocks that contain sulphur. As they use this energy, the bacteria create heat and can increase the amount of acid/metals released from these types of rocks.

The bacteria that contribute to the production of Acid Rock Drainage (ARD) are active at the Faro Mine Complex, and scientists predict that the amount of metals released in ARD will continue to increase for hundreds of years.

In the future, the release of metals could seriously affect waters downstream of the old mine complex, unless something is done to control them. Key features of the recommended closure and remediation plan are minimizing the generation of metals and acid as well as treating any contaminated water before it flows into creeks running through the mine complex.

Stability of Key Physical Structures

A series of dams in the Rose Creek valley keep tailings and contaminated water in place. Failure of any of these structures could cause tailings to escape and affect areas downstream of the mine for a long time.

Clean water in Faro Creek, Rose Creek and Vangorda Creek flows around the site in diversion channels. If any of the channels fail, clean water flowing into pits, tailings or waste rock will become contaminated.

To address these potential issues, the recommended closure and remediation plan includes upgrading and/or replacing dams and diversion channels to ensure tailings stay in place during natural events such as floods and earthquakes.

Dust Creation and Transport

The 55 million tonnes of tailings stored in Rose Creek Valley are made of finely ground-up rock, resembling sand and containing residual amounts of metals. Wind can pick up fine particles of tailings and blow them several kilometers from the mine site; wind-blown contamination will be higher near dusty sources and decrease further away from the site. Creation and transport of dust may have significant impacts on the terrestrial environment in the long term if no control measures are put in place.

Over the long term, control of tailings dust will be addressed in the closure and remediation plan. In the meantime, the technical team has been working with current care and maintenance staff on-site to design an interim measure to control dust. This involves spraying a compound over key areas of the tailings, effectively 'sealing' the surface and creating a hard crust. The material is first mixed with water and applied by a vehicle-mounted sprayer, with periodic re-applications as needed.

Human and Animal Contact

Repeated, long-term contact with waste materials may have negative impacts on the surrounding flora and fauna of the area. Another key feature of the recommended closure and remediation plan will include methods of minimizing contact with waste materials by covering tailings and waste rock with engineered soil covers.

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