Mine Tailings Storage: Safety Is No Accident
Options Disadvantages Overview of environmental issues related to major tailings storage and disposal techniques Advantages
Without dewatering Impoundments
More economical construction; Maintaining water in the tailings reduces the possibility of acid mine drainage by restricting oxidation of sulphides.
Water-intensive; High risk of seepage; High risk of damage in the event of dam failure due to large volume of water; Large footprint and habitat disturbance;
Rehabilitation only possible after mine closure. Additional costs (thickening, paste, pumping); Relatively large footprint and loss of habitats; Moderately water-intensive; Paste tailings can be costly to pump; Rehabilitation only possible after mine closure.
With thickened or past tailings Impoundments
Lower risk of damage caused by dam failure; Lower risk of seepage due to smaller volume of water; Reduced volume of tailings; Slightly smaller footprint. Lower risk of damage caused by dam failure; Lower risk of seepage due to less water; Smaller footprint to store separate waste streams.
With co-disposal of tailings and coarse grained waste Impoundments Paste tailings and binder Backfilling With dewatering after closure Impoundments
Additional costs (thickening, paste, pumping, barricade, binder); Seepage; Only for underground mines. High capital costs and moderate operational costs with modern filtration and conveying technology; Requires surface management system to prevent wind and water erosion. Additional costs (Thickening, Paste, Pumping, larger dam required); Relatively large footprint and habitat loss; Moderately water intensive; Paste tailings can be costly to pump; Rehabilitation only possible after mine closure. Only slightly more costly than impoundments without dewatering; Post-closure drain seepage probably needs passive treatment.
Economical construction (a drain system must be installed before operation).
Reduced surface storage area; Low risk of groundwater contamination; More water is recycled and more volume of tailings is reduced; Minimal rehabilitation required. Reduced water use; Elimination of the risks of catastrophic tailings flow associated with dam failures; Reduction of risk of groundwater contamination through seepage; Reduced storage footprint enabling progressive rehabilitation during mine operation; Easier to gain a permit for; Potential for treatment of long-term seepage if potentially acid
generating (PAG) material is dry stacked; Some progressive reclamation possible. Low capital and operating cost.
Environmental contamination and disturbance; Difficult to gain a permit for; Water-intensive due to low water recovery; Difficult or impossible to mitigate impacts. Environmental contamination and disturbance; Mass wasting from the ground sites; Difficult to gain a permit for; Water-intensive due to low water recovery; Lack of data on environmental impacts; Difficult or impossible to mitigate impacts.
Sub-marine and deep marine
Low capital and operating cost.
Table 2. Overview of environmental issues related to major disposal techniques
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