Q2. What are the future works in "Mine tailings dams: characteristics, failure, environmental impacts, and remediation" ?
Further collaborative research in the fields of engineering ( e. g., the influence of cementation on impoundment stability ), geomorphology ( e. g., the effects of changing flood occurrence on the remobilisation of contaminated floodplain sediments ), mineralogy ( e. g., the secondary mineral contaminant-sink assemblage ), chemistry ( e. g., the influence of oxidation on particular minerals ) and toxicology ( e. g., quantifying the role of the wind as a contaminant vector ) is required. It may be, however, that the accounting practices applied to the individual companies concerned do not provide a full and accurate assessment of the potential environmental cost and risk of tailings dam failure.
Q3. What is the effect of tailings dam spills on the biota?
Tailings dam spills can contaminate natural waters in the short-term, but in the medium- to longerterm (years to centuries) contaminant concentrations are likely to fall because of the effects of sediment and aqueous dilution and uptake by solid phases in the river bed and floodplain.
Q4. How did the water collected after the dam breach fall to the levels of pb?
Sampling on 12 and 13 November 1996 showed that river waters collected nextto the dam breach had > 2,500 mg L-1 Pb, and that this only fell gradually over 50 km to concentrations of ~ 500 mg L-1.
Q5. What are the main methods of handling and storage of tailings?
Approaches to the handling and storage of tailings include riverine disposal, submarine disposal, wetland retention, backfilling, dry stacking and storage behind dammed impoundments (Lottermoser, 2007).
Q6. How many tonnes of tailings were released into the Pilcomayo catchment?
For instance,immediately after the March 1626 failure of the Bolivian San Ildefonso dam, enormous quantities of tailings and Hg amalgam were released into the Pilcomayo catchment (Rudolph 1936; Gioda et al., 2002).
Q7. What are the main factors that affect the formation of secondary minerals?
Depending on the interaction between source mineralogy and localconditions, such as pH, climate and redox state, particular secondary minerals may form.
Q8. What is the common method of construction for tailings dams?
Tailings dams are commonly constructed from readily available local materials, rather thanthe concrete used, for example, in water-retention dams.
Q9. What are the main economic consequences of tailings dam failures?
In addition, tailings dam failures may lead to further losses arising from business and supply chain interruption, particularly when large third party material damage or casualties occur and authorities close down an operation (e.g., Mahrla, 2011).
Q10. What is the common remedial measure for tailings dam spills?
The most common remedial measure taken for tailings dam spills, however, is the removalof the spilled tailings from the affected areas to a storage area.
Q11. What is the way to preserve the structural integrity of a tailings dam?
In order to preserve structural integrity of successive raises of dams, they are ideallyunderlain by a competent sand-sized layer rather than a loose, potentially incompetent clay-sized.
Q12. How many tonnes of tailings were released into the catchment?
Lásló (2006) calculated that the January spill released up to 120 tonnes of cyanide and metallic elements into the catchment, whereas the March spill, although not as extensive, released significant amounts of Pb, Cu and Zn.
Q13. What is the way to prevent the formation of a tailings dam?
To that end it is appropriate to allow for good drainage of the dam by providing for a wide tailings ‘beach’ (defined as the sub-aerial tailings disposal point), which differentiates the tailings material by size, ensuring that the sand size larger (more permeable) particles form the dam structure, whereas finer (less permeable) clay sized particles are more distally dispersed.
Q14. What is the importance of good maintenance programmes?
Good maintenance programmes are, therefore, an essential requirement of effective tailings impoundment management, a vital component of which is a comprehensive surveillance programme (Martin and Davies, 2000).
Q15. What is the common method of construction for retaining embankments?
Rather than initially installing a finalized full capacity structure, intermediate retaining embankments are normally constructed and then raised as storage demand increases (Lottermoser, 2007).
Q16. What is the effect of tailings dam failures on the environment?
The sheer magnitude and often toxic nature of the material held within tailings dams means that their failure, and the ensuing discharge into river systems, will invariably affect water and sediment quality, and aquatic and human life for potentially hundreds of km downstream (Edwards, 1996; Macklin et al.
Q17. How much of the estimated total production of Pb is stored in the Swale catchment?
Dennis et al. (2009) have calculated that 155,000 tonnes of Pb, or 28% of the estimated total production, is stored within fluvial sediments in the Swale catchment.
Q18. What is the role of negatively charged oxygen atoms in secondary minerals?
In this respect the negatively charged oxygen atoms in secondary minerals such as sulfates, carbonates, phosphates and arsenates may be significant sorption sites, with the negatively charged hydroxyl and oxygen ions found on the surface of primary and secondary oxide and clay minerals of particular significance.