User:Oceanflynn/sandbox/tailings ponds

Tailings ponds or tailings impoundments are facilities designed to receive, store and process waste tailings on-site usually near extraction plants and often associated with mining, milling and heavy oil industries. The tailings ponds serve as sediment traps in which tailings settle gradually, sometimes with the use of coagulants, flocculants or other agents to facilitate the process. While a tailing pond can be built in a naturally occurring depression—a basin, gorge or valley, or a basin—at a distance of several kilometers from a concentration plant, they are often contained by dams and/or buttresses. The resulting tailings water can be reused in the extraction process. Recent technological efforts are being made to reclaim tailings ponds. Tailings ponds are usually stable but when a tailings dam overflows or the dam bursts during floods or flash rains, there is an environmental risk as toxic materials are unleashed through mudflow or flooding..

In some mining processes tailings ponds hold and process residue that was used to wash ore. In tailings ponds, metals and other dangerous or toxic elements that were either trapped underground or unexposed to the oxidizing environment, become exposed. Also acidic wastes amplify the leaching of these metals and toxic elements.

Toxicity of effluents
While tailings ponds are usually stable and safe there are environmental risks due to the toxic nature of by-products of extraction which can harm wildlife that come in contact with the toxic water, affect air quality and in the case of dam bursts during periods of flash rains, overland flooding, structural issues or overfilling, surrounding areas including ground water, can be exposed to high levels of toxins.

Tailings and waste rock analyses
Tailings are fine-ground waste by-products of the recovery or extraction processes to obtain metal, minerals, and heavy oil used either directly by consumers and/or by the agricultural, mining and petroleum industries. Some of the tailings are created as large quantities of rock and/or sand are mined, crushed, pulverized, and processed to recover metal, mineral values and/or oil. These extraction and recovery processes often produce tailings, enormous quantities of fine-grained, fine rock particles as by-products, "in sizes ranging from sand-sized down to as low as a few microns."

In the United States alone there has been a dramatic rise in the number and size of tailings ponds or tailings impoundments since the 1970s with the corresponding growth in the mining industry..

Disposal of tailings
The U.S. Environmental Protection Agency noted that the most common method used for tailings disposal was the "disposal of tailings slurry in impoundments.". Other methods of tailings disposal include the use of free-standing piles of dry tailings, backfilled underground mine shafts and open-pit storage. These tailings impoundments are "tailings impoundments are engineered structures for permanently disposing of the fine-grained waste from mining and milling operations. At some projects, tailings embankments reach several hundred feet in height and the impoundments cover several square miles."

Concerns of public and legislative bodies
By 1989, there was a rise in concern about the need for sound design in the construction of dams for tailings impoundments in the uranium industry, according to a leading international authority in tailings management, Dr. Gordon M. Ritcey of Curtin University's Western Australian School of Mines. Dr. Ritcey speculated that this resulted in more careful scrutiny of the construction of tailings ponds in other industries.

Corporate responsibility
By 1976 in the Athabaska oil sands region there were advances being made, such as slope stability analysis, into the safe construction of embankments that would prevent seepage of toxic elements from the oil sands tailings ponds.

Tailings ponds reclamation
Tailings ponds reclamation projects were already being considered by 1989. The tailings in tailings ponds

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 * Oil sands tailings ponds This is a parallel sandbox project that has potential content references of relevance to this sandbox article "Tailings ponds".