The Syncrude Mildred Lake Tailings Dyke in Alberta, Canada, is an embankment dam about 18 kilometres (11 mi) long and from 40 to 88 metres (131 to 289 ft) high. It is the largest dam structure on earth by volume, and as of 2001 it was believed to be the largest earth structure in the world by volume of fill.

How many tailings dams are there in the world?

There is no comprehensive global registry of tailings dams. It is estimated there are around 18,000 dams, 3,500 of which are active.

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.

What is the purpose of a tailings dam?

Tailings dams are used to store water and waste that come as by products from the mining process. It is estimated there are at least 3,500 tailings dams around the world.

What happens to tailings dams?

Tailings are pumped into a pond to allow the sedimentation – or separation – of solids from the water. The water removed from tailings dams can be, and often is, later reused in the mine's processing cycles.

Ep.12 How the mining industry is responding to tailings dam failures

20 related questions found

What is in a tailings dam?

A tailings dam is typically an earth-fill embankment dam used to store byproducts of mining operations after separating the ore from the gangue. ... Copper, gold, uranium and other mining operations produce varied kinds of waste, much of it toxic, which pose varied challenges for long-term containment.

How are tailings formed?

Tailings consist of ground rock and process effluents that are generated in a mine processing plant. Mechanical and chemical processes are used to extract the desired product from the run of the mine ore and produce a waste stream known as tailings.

Why do tailings 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.

How do tailings affect the environment?

Mine tailings are the materials left over after the process of separating the desired product from an ore. They often consist of fine particles suspended in water, which have the potential to damage the environment by releasing toxic metals, causing erosion and sinkholes, and contaminating soil and water supplies.

What tailing means?

/teɪl/ to follow and watch someone very closely, especially in order to get information secretly: That car has been tailing me for the last ten minutes.

Are tailings dams safe?

Hazard from seismic events

Upstream tailings dams are known to have very poor properties during seismic events. During cyclic mechanical stress, as experienced during seismic events, the tailings slurries (including the material used for the dam) may liquefy.

What are tailing piles?

Tailings are a type of rock waste from the mining industry. When a mineral product is mined, the valuable portion is usually embedded in a rock matrix called ore. Once the ore has been stripped of its valuable minerals, sometimes through the addition of chemicals, it is piled up into tailings.

Which country has the most high risk upstream dams?

South Africa has the highest number of dangerous tailing dams—structures constructed, often by mining companies, to store waste in liquid form. The dams are considered hazardous if improperly handled and have resulted in environmental disasters and deaths many times around the world.

What is the difference between mine waste and tailings?

Waste rock is bedrock that has been mined and transported out of the pit but does not have metal concentrations of economic interest. Tailings are the finely ground residuals that remain after the mill process has removed the valuable metals from the ore.

What is dam and types of dam?

• 1) Diversion Dam. Like the name says, a diversion dam is used to divert water. ...
• 2) Buttress Dam. Buttress dams can take many forms, but they all consist of a sloping deck supported by intervals of buttresses. ...
• 3) Embankment Dam. ...
• 4) Cofferdam. ...
• 5) Storage Dam. ...
• 6) Detention Dam. ...
• 7) Gravity Dam.

Are tailings toxic?

Tailings aren't “toxic.” They are a natural byproduct to be kept in a lined facility and returned to the pit at closure. All pyritic tailings will be backhauled to the pit for permanent underwater storage. They will present no failure risk and offer no threat to downstream habitat.

Why are tailings so controversial?

What are tailings and what are they so controversial? They lead to much of the pollution associated with mining. Where does mineral processing usually begin? at the mining site.

How can we reduce tailings?

Here are three of the more common alternatives, which can also reduce or avoid the need for water-covered TSFs: Paste or thickened tailings on surface – One way to help reduce the amount of water going to the TSF is through thickening the tailings, so that the product moves through the pipe in a plug-flow rather than a ...

Has any dam broke?

Dam failures are comparatively rare, but can cause immense damage and loss of life when they occur. In 1975 the failure of the Banqiao Reservoir Dam and other dams in Henan Province, China caused more casualties than any other dam failure in history.

How many dams have failed in the US?

Yet about 1,000 dams have failed over the past four decades, killing 34 people, according to Stanford University's National Performance of Dams Program. Built for flood control, irrigation, water supply, hydropower, recreation or industrial waste storage, the nation's dams are over a half-century old on average.

What are tailings in the mining industry?

Tailings are the mineral waste remaining after the processing of ore to extract mineral concentrates and are typically stored within an engineered containment structure known as a tailing storage facility or TSF.

Can tailings be recycled?

Especially, the recycling of gold mine tailings is indispensable for mining and brings about additional income. ... These wastes are partially reutilized as construction materials, red tide remover, lower grade pigment, etc.; however, most of them are not recycled (Lee, Hwang & Bae, 2006, 2009).

What is a downstream tailings dam?

Downstream tailings dams are raised progressively “downstream” of the starter dam, with an internal drain or filter. They often have an impervious layer (low permeability zone) on the upstream slope of the dam (labelled “core” in Figure 3).

What are toxic tailings?

Tar sands mining operations have generated over 250 billion gallons of toxic tailings – a poisonous brew of water, sand, silt, heavy metals and other petrochemical waste products – which they store in toxic lakes that cover an area greater than Manhattan and Boston combined.