It is vital to gain a better understanding of the processes contributing to the development of physicochemical gradients (pH, Eh, Oxygen etc…) that form in these tailings ponds over time, with the goal of remediation and subsequent construction of end-pit lake systems once oil extraction has ceased.
Mine tailings were spread over the site, and the area was planted with grass.
Although these tailings were deposited over the entire history of mining at the LCMS; the older tailings are capped with recently deposited material released by the 1996 log dam failure (the approximate extent of this material is shown by the gray shading in the inset box in Figure 1).
The permit allowed Coeur to dump 4.5 million tons of a combination of waste rock and tailings into Lower Slate Lake over a period of ten years, causing the floor elevation of the lake to rise by 50 feet.
Now, instead, there are some of the darker sides of capitalism: Western entrepreneurs picking over the old tailings from the steel plants for what was left unrefined, paying low wages in a county with a jobless rate of 20.3percentt, nearly three times the national unemployment rate of 6.5percentt.
And the planned waste facility — where as much as 14.6 million tons of waste rock and 7.2 million tons of tailings would be deposited over the expected nine-year life of the mine — would be about 150 steps from the river.
Four of the cells were constructed with CCBEs over the tailings, while the fifth tailings cell was left uncovered.
The simulations also illustrate how the behaviour and efficiency of a monolayer cover placed over reactive tailings depend on specific factors, including water table position, initial porewater chemistry, and cover materials' hydrogeological properties and thicknesses.
Chemical stabilization aims to prevent wind and water erosion using a chemical agent such as a lignin sulfonate or a resinous adhesive to form a crust over the tailings, also a temporary stabilization technique, as these crusts can eventually fail (Tordoff et al. 2000).
