技术报告-尾矿库设计及评估 (英文)

Design and Evaluation of Tailings Dams

Figure 4. Single (a) and Multiple (b) Side-Hill Impoundments

(Source: Vick 1990)

Other types of valley impoundments may be employed when there is an excessively large drainage catchment

area and/or there is a lack of necessary valley topography. Two variations are the side-hill impoundment and

the valley-bottom impoundment. The side-hill layout consists of a three-sided dam constructed against a

hillside (Figure 4). This design is optimal for slopes of less than 10% grade. Construction on steeper slopes

requires much more fill volume to achieve sufficient storage volume (especially when using the downstream

method of construction).

If the drainage catchment area is too large for a cross-valley dam and the slope of the terrain is too steep for a

side-hill layout, then a combination of these two designs, the valley-bottom impoundment, may be considered

(Figure 5). Valley-bottom impoundments are often laid out in multiple form as the valley floor rises, in order

to achieve greater storage volume. Because the upstream catchment area is relatively large, it is often, or

usually, necessary to convey upstream flows around (and/or under) valley-bottom impoundments.

The valley dam configurations are often the optimum choice for economic reasons. This is because the valley

walls form one or more sides, so that the dam length is reduced, minimizing construction costs. However,

decreased construction costs and low average depth of tailings in the embankment may be offset by increased

environmental mitigation and increased costs of shut-down and reclamation.