How are tailings dams built?

Upstream construction begins with a starter dam. The tailings are then discharged into the facility where they form a tailings beach. The deposited tailings adjacent to the dam wall is allowed to drain and then can be compacted to be used to form the foundation for subsequent levels of the wall as the dam is raised.

What are tailings in construction?

Tailings are the waste materials left after the target mineral is extracted from ore. They consist of: Crushed rock. Water.

What three environmental problems are caused by tailings?

Tailings can reach immense proportions, appearing in the form of large hills (or sometimes ponds) on the landscape. Tailings deposited as large piles can cause a variety of environmental problems: Slumps, landslides. Tailing piles can be unstable, and experience landslides.

How much does it cost to build a tailings dam?

Tailings dams are an economic solution to the management of refuse. The cost of tailings dams is somewhere in the range from $1 per tonne to $5 per tonne of tailings deposited, and, adding societies true cost, it could be argued the cost is actually between $2 per tonne and $10 per tonne.

Why do tailing dams fail?

In the literature on the topic, the majority of the tailings storage-facility failures discussed can be attributed to a few factors – in particular, the lack of management continuity and inadequate resourcing (especially financial) for the facility.

What are tailings used for?

Tailings ponds are used to store the waste made from separating minerals from rocks, or the slurry produced from tar sands mining. Tailings are sometimes mixed with other materials such as bentonite to form a thicker slurry that slows the release of impacted water to the environment.

What is tailing dam failure?

The mine tailings is used to create a barrier. The dam gets higher as more tailings are stored behind them, increasing the risk of collapse. Upstream dams can become unstable and leak if the mine waste behind the dam gets too wet. This will damage the dam and may cause it to collapse.

How many tailings dams are in Australia?

In 2019 BHP announced that 32 of its 67 tailing dams were built using the upstream method and classified as ‘high risk or worse. ‘ Four of the five ‘extreme risk’ dams are in Australia – Mt Whaleback iron ore mine in WA and three at Olympic Dam in South Australia.

How tailings are formed?

Tailings are a by-product of mining. After ore containing an economically-recoverable commodity is mined from the earth, that commodity is extracted in a processing plant or mill. After the commodity of value is extracted from the ore material, the resultant waste stream is termed “tailings”.