Heap Leach Plant Site Selection and Construction

The heap leaching site must be in an area with uniform soil texture and sufficient strength to carry thousands of tons of ore and equipment, so as to ensure that there will be no local subsidence, damage the leaching pad and loss of gold containing leaching solution. In addition, the site is required to have a certain slope to collect and outflow the leaching solution, but it should not be too large to prevent the bottom pad from sliding.

1. Heap leaching structure

The construction of heap leaching directly affects the porosity and solution permeability uniformity in the ore heap. Therefore, the occurrence of coarse and fine particle segregation and ore heap compaction should be avoided as far as possible. The height of ore pile is determined by test, generally 2 ~ 9m.

2. Technical conditions of heap leaching

(1) The particle size of loose and porous ore can be coarser, generally – 50 or – 30 mm, and the relatively dense ore can be controlled at – 10 mm.

(2) The cyanide concentration in the leaching solution is generally controlled between 0.025 ~ 0.1%. In practice, it is best to control it by stages according to the later three stages of junior middle school, which is higher in the initial stage and lower in the later stage.

(3) The pH value of the leaching solution is generally controlled between 9.5 ~ 11. The usual operation is to wash the heap with clean water after the heap is built, remove metal impurities, and wash the heap with saturated lime water or caustic soda liquid until the pH value of the liquid discharged from the bottom of the heap reaches more than 9.5.

(4) Spray intensity and leaching time.

3. Adsorption and recovery of gold containing solution

Carbon adsorption is usually used for gold recovery. There are a variety of specific adsorption devices, which are essentially the same and have different efficiency. Small and medium-sized storage yards are mostly adsorbed by series carbon columns.