Heap Leach Drainage Designs
Heap leach operations have gained popularity in the past while around the world as a reasonable method for extracting metals such as gold, copper, and nickel from earth material. In such heap operations, however, the success of the leaching operation depends on the flow regime established by the sprinklers at the top of each lift and the drainage system at the bottom.
Each lift represents a unique unsaturated flow system, which is established in order to provide a targeted saturation range and to allow the presence of oxygen in the heap layer. Through the three-dimensional saturated and unsaturated flow software features in SVFlux, it is now possible to determine how to optimize the speed of the drainage through the use of a drainage pipe system in the over-liner material. There are two primary types of design, which can be analyzed for this pipe system: a herringbone type design, and a parallel pipe design.
This particular problem is more appropriate for 3D and cannot be reasonably modeled using a 2D system, due to the lateral aspects of the flow regime.
A herringbone type of drainage structure, as well as a parallel type of drainage pipe structure can be set up as shown in the figures on the right.
Figure 1: Location of herringbone drains (3x vertical exaggeration)
Figure 2: Herringbone pipe layout of Design 2