Are tailings ponds lined?

Are tailings ponds lined?

Tailings ponds are lined with compacted sand and a layer of fine clay. The clay has a low permeability rate which helps prevent tailings water from seeping into the groundwater. All seepage water and contaminated perimeter water (from rain or melting snow) is pumped back into the process.

How does a tailings dam work?

Tailings dams can be huge in size, as big as lakes, and reach 300 metres high. As the slurry of waste is piped into the dam, the solids settle to the bottom and the water is recycled to be used in the separation process again. Rather than reinforced concrete, tailings dams use earth or rock to create a barrage.

What do mine tailings contain?

Tailings are Mine Waste

• Crushed rock.
• Water.
• Trace quantities of metals such as copper, mercury, cadmium, zinc, etc.
• Additives used in processing, such as petroleum byproducts, sulfuric acid and cyanide.

Why are mining tailings bad?

Tailings, especially tailing stored in water by tailings dam in ponds, can be dangerous sources of toxic chemicals, such as heavy metals, sulfides and radioactive content. These ponds are also vulnerable to major breaches or leaks from the dams, causing environmental disasters.

What are tailings ponds used for?

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.

Why are tailings ponds negative for the environment?

There are several environmental concerns that are associated with the existence of tailings ponds. The main problem with the ponds is that they include toxic and harmful chemicals such as ammonia, mercury, and naphthenic acids. The water containing these chemicals is toxic to animals, particularly aquatic organisms.

How long do tailings dams last?

According to mining engineer David M Chambers of the Center for Science in Public Participation, 10,000 years is “a conservative estimate” of how long most tailings dams will need to maintain structural integrity.

What are tailings and why are they so controversial?

Minerals are processed so we can gain access to the desired minerals. What are tailings and what are they so controversial? They lead to much of the pollution associated with mining. while the mines cause habitats to be temporary destroyed and miners can get lung diseases from breathing in mineral particles in the air.

Why are tailings so controversial?

Research from Canada’s environmental agency has shown that tailings ponds in the tar sands region have leached potentially deadly toxins into land and groundwater, and First Nations tribes and environmentalists have blamed those leaching chemicals from the tar sands on rare cancer clusters.

What chemicals are in tailings?

Tailings from oilsands can contain napthenic acids, polycyclic aromatic hydrocarbons, phenolic compounds, ammonia, lead, mercury, and other metals.

What is the dirtiest type of mining?

According to the U.S. Environmental Protection Agency’s Toxics Release Inventory, metal mining is the nation’s #1 toxic polluter.

Are tailings ponds toxic?

Oil sands tailings pond in Fort McMurray, Alberta. The Oil sands tailings ponds are settling ponds that contain the waste byproduct of oil sands extraction and upgrading. The main problem with the ponds is that they include toxic and harmful chemicals such as ammonia, mercury, and naphthenic acids.

How are tailings thickened in a tailings dam?

Tailings are thickened into a paste by removing excess water and recycling the water back into the mine processing stream via holding ponds. First adopted in the 1980s]

What kind of liner is used for tailings ponds?

Solution ponds are normally lined with HDPE as an exposed liner. Tailings dams can be lined with PVC or HDPE. Tailings dams use liners to prevent the release of concentrated mine chemicals into the environment. Tailings ponds and dams accumulate the solids remaining from the mining operation, often in the form of a fine sand.

Are there any tailings dam failures in the US?

Recent major tailings dam failures have led to an industry-wide review of the design and management of tailings storage facilities.

When did ANCOLD produce tailings dam design guidelines?

ANCOLD produced their “Guidelines on Tailings Dam Design, Construction and Operation” in 1999. Since that time the publication has been widely used within Australia and internationally where the expertise of Australian practice has been recognised.