What is a decant tower?
What is a decant tower?
A decant tower is an intake structure consisting of a vertical or inclined hollow tower (riser) allowing the free water to be pumped out of the tower or drain by gravity via a buried conduit.
What are tailings impoundments?
Tailing ponds are areas of refused mining tailings where the waterborne refuse material is pumped into a pond to allow the sedimentation (meaning separation) of solids from the water. The pond is generally impounded with a dam, and known as tailings impoundments or tailings dams.
Why are tailings a problem?
The storage of tailings under water can effectively hinder the chemical reactions that they undergo. However, tailings dams frequently fail, resulting in the discharge of significant quantities of tailings into the natural environment, thereby causing grievous casualties and serious economic losses.
What do tailings ponds do?
Tailings ponds are engineered dam and dyke facilities used for storage of tailings materials. Tailing ponds are also used to enable water to separate from the tailings. Water from the tailings ponds is recycled back into the extraction process, reducing the use of fresh water from the Athabasca River and other sources.
Do reclaim ponds reduce the risk of surface tailings failure?
This strengthens the argument that these methods of surface tailings storage have a lower risk of failure as water management is reduced or virtually eliminated. However, reclaim ponds may be used to capture surface runoff or any bleed water as the tailings deposit within the facility.
What is the difference between a decant tower and a barge?
Unlike decant towers that are gravity fed, a decant barge requires power to operate the pumps that decant the water from the supernatant pond. This increases operating costs as a constant and reliable power source is required to ensure the pumps operate. If a power failure occurs then no water can be decanted.
What should the design of the Decant system allow for?
The design of the decant should allow for a high surge capacity of storm water to compensate for near future storm events. If the pond cannot drain fast enough (decant system or reclaim/evaporation pond ingress restriction), then the freeboard of the TMF may be lost if a near future storm reoccurs.
What is a “tailings dam?
These Guidelines use the term “Tailings Dam” to represent the structure built to contain the tailings as well as the tailings stored. The scope of the Guidelines does not extend to all aspects of the Tailings Storage Facility (TSF) which may include a range of associated structures and infrastructure.
