Mine tailings dams: Characteristics, failure, environmental impacts, and remediation

Abstract

On a global scale demand for the products of the extractive industries is ever increasing. Extraction of the targeted resource results in the concurrent production of a significant volume of waste material, including tailings, which are mixtures of crushed rock and processing fluids from mills, washeries or concentrators that remain after the extraction of economic metals, minerals, mineral fuels or coal. The volume of tailings is normally far in excess of the liberated resource, and the tailings often contain potentially hazardous contaminants. A priority for a reasonable and responsible mining organization must be to proactively isolate the tailings so as to forestall them from entering groundwaters, rivers, lakes and the wind. There is ample evidence that, should such tailings enter these environments they may contaminate food chains and drinking water. Furthermore, the tailings undergo physical and chemical change after they have been deposited. The chemical changes are most often a function of exposure to atmospheric oxidation and tends to make previously, perhaps safely held contaminants mobile and available. If the tailings are stored under water, contact with the atmosphere is substantially reduced, thereby forestalling oxygen-mediated chemical change. It is therefore accepted practice for tailings to be stored in isolated impoundments under water and behind dams. However, these dams frequently fail, releasing enormous quantities of tailings into river catchments. These accidents pose a serious threat to animal and human health and are of concern for extractive industries and the wider community. It is therefore of importance to understand the nature of the material held within these dams, what best safety practice is for these structures and, should the worst happen, what adverse effects such accidents might have on the wider environment and how these might be mitigated. This paper reviews these factors, covering the characteristics, types and magnitudes, environmental impacts, and remediation of mine tailings dam failures.Peer reviewe

Improvement of Traditional Mining Tailings Storage Facilities

“…As a matter of fact, due to the natural disasters and/ or extreme weather events, several dam failures and catastrophes of tailings release have occurred over the past years. According to the United Nations Environment Program (UNEP) and International Commission on Large Dams (ICOLD) [6,7], the main reasons for these failures and events are the inadequate regulation of water balance and tailings deposition homogeneousness, the absence of advanced tailings dam construction methods and the lack of safe operations. In October 2010, substantial widespread farmland and water were polluted by an unparalleled disastrous release of ~0.7 million m 3 of red slurry in Ajka, Hungary [8].…”

“…Traditional mining tailings storage facilities have faced an enormous challenge to the treatment and disposal of tailings and require a multidisciplinary research, because the tailings can pollute environment by AMD and lead to tailings dam failures due to leakage, instability, liquefaction, and poor design [16,7]. Since the 1960s, 77 mining tailings dams have collapsed worldwide mainly because of the geotechnical instability, and caused at least 471 deaths as well as environmental destruction and serious economic impacts [17].…”

Industrial mining heritage and the legacy of environmental pollution in the Derbyshire Derwent catchment: Quantifying contamination at a regional scale and developing integrated strategies for management of the wider historic environment

“…Their distribution process may be defined as active or passive. Active transformation occurs when the mining sediment transforms the river channel; for example, in the wake of a tailings dam spill (Kossoff et al, 2014). By contrast, passive dispersion occurs when mining-contaminated particulates are disseminated as part of the normal sediment load in the fluvial regime (Macklin et al, 2006).…”

Sediment-associated contaminant transport and storage dynamics in the Quesnel River from the Mount Polley Mine disaster

“…Breaches or failures to mine tailings storage facilities (TSF) are often catastrophic, impacting water and sediment quality, as well as aquatic life in rivers and lakes below the TSF (Azam and Li 2010;Kossoff et al 2014;Rico et al 2008). …”

“…The degree of contamination and the long-term impacts on the receiving aquatic system depend on four factors: the quality, quantity, and the rate of discharge of materials into receiving waters, and the effectiveness of the clean-up (Graf 1990;Macklin et al 2006). A review of historical TSF breaches by Kossoff et al (2014) indicated quantities of tailings released ranged from 100,000 -7,000,000 m 3 ; all of these are at least three times smaller than the estimated 25,000,000 m 3 released by the 2014 Mt Polley Mine TSF breach. Recently, there was a larger breach in Brazil in 2015 (Table 1.2).…”