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Heap Leaching

Heap Leaching

At Amulsar, gold will be extracted by heap leaching method. The modern heap leaching method was first applied in the USA in the 1960s. So, Nevada state, USA, is the place of origin of the modern heap leaching method. The method does not require extensive crushing of the rock and operation of big treatment plants. Besides, no tailings dump is needed for the mine wastes, in case of the heap leaching.  

Heap Leaching at the Amulsar 

Two types of rock are extracted from the pit: the rock that bears valuable metals that is called ore and the barren rock. Crushed ore will be transported by a conveyor to the heap leach pad where the gold will be extracted. Dilute cyanide solution will be applied to the ore heap using drip emitters. Afterwards cyanide solution that bears the gold will be directed to the process pond from where it is pumped to gold extraction ADR plant. After the gold is extracted, cyanide is added to the solution as a new batch of material keeps being added during the process. The leach solution continues to be pumped back to the process without discharged to the environment.       

Heap leach pad has composed liners to prevent seepage. So, this is a closed cycle with the solution continuously circulated through the system. After the mine closure, water with no cyanide will be added and circulated for several months until the heap is cleaned from cyanide.  Then, the heap is covered with clay and soil and revegetated. 

Distance Between Heap Leach Platform and the Residential Settlement

There is no limit set on the distance of heap leach pad. The reason is that a properly designed pad may be placed at any distance provided that the pad is constructed and managed in compliance with the requirements of the International Cyanide Management Code. Cyanide may be as safe as any other chemical substance, used in the production, on the condition of a proper and accurate management of the cyanide. In case of Amulsar, the settlement, nearest to the heap leach pad, is Gndevaz located at a distance of some 1 km. Globally, there are other mines with the heap leach pads located as close as the Amulsar one or even closer.  For example,

  • Cripple Creek (Colorado, USA), the distance from the closest settlement is 0.7 km, the population is 1189
  • Round mountain (Nevada, USA), the distance from the closest settlement is 3 km, the population is 1868
  • Miami mine (Miami, USA), the distance from the closest settlement is 1 km, the population is 1837
  • Sierrita Green Valley (USA), the distance from the closest settlement is 1 km, the population is 23 765.