技术报告-尾矿库设计及评估 (英文)

Design and Evaluation of Tailings Dams

It should also be noted that tailings dam engineering is continually evolving. The relatively recent emphasis

on environmental performance is leading to many changes in the field, many of which are as yet not fully

tested. Vick (1990) may be the most recent and most comprehensive examination of the topics covered by

this report. Consequently, certain sections of this report rely heavily on Vick's approach.

The next section of this report provides an overview of the various methods used to dispose of mine tailings

and the types of impoundments that are used. Section 3 describes the basic concepts used in the design of

impoundments, including a number of site-specific variables of concern. Section 4 discusses tailings

embankment and stability, while Section 5 briefly discusses water management in tailings impoundments. A

case study on a lined tailings impoundment is presented in Section 6. Finally, Section 7 lists all references

cited in the text.

2.OVERVIEW OF TAILINGS DISPOSAL

The ultimate purpose of a tailings impoundment is to contain fine-grained tailings, often with a secondary or

co-purpose of conserving water for use in the mine and mill. This has to be accomplished in a cost-effective

manner that provides for long-term stability of the embankment structure and the impounded tailings and the

long-term protection of the environment. In the process of designing any tailings embankment and

impoundment, these three interests, cost, stability, and environmental performance, must be balanced, with

situation-specific conditions establishing the balance at each stage of the process. It is worth noting that the

long-term costs of tailings disposal depend in part on mechanical stability and environmental integrity, such

that stable and environmentally acceptable structures promote cost effectiveness.

Impoundment of slurry tailings is the most common method of disposal and are the main focus of this report.

Impoundments are favored because, among other things, they are "economically attractive and relatively easy

to operate" (Environment Canada 1987). Tailings impoundments can be and are designed to perform a

number of functions, including treatment functions. These include (Environment Canada 1987):

Removal of suspended solids by sedimentation

Precipitation of heavy metals as hydroxides

Permanent containment of settled tailings

Equalization of wastewater quality

Stabilization of some oxidizable constituents (e.g., thiosalts, cyanides, flotation reagents)

Storage and stabilization of process recycle water

Incidental flow balancing of storm water flows.