Heap leaching of gold mine-heap building method
2020-07-14 10:02Introduction：Heap leaching Heap buildingmethods include multi-pile method, multi-layer method, slope method and hoisting method. Commonly used heapbuilding machinery has trucks, bulldozers (crawler type). Cranes and belt conveyors. Because the method o
Heap leaching
Heap building methods include multi-pile method, multi-layer method, slope method and hoisting method. Commonly used heap building machinery has trucks, bulldozers (crawler type). Cranes and belt conveyors. Because the method of building the heap directly affects the permeability of the heap and the recovery of gold, it becomes the key to the success or failure of the heap leaching method. The United States Bureau of Mines has investigated 22 ore heaps. Of these, 11 have failed due to improper heap building methods. The current methods and advantages and disadvantages of these methods are as follows:
The multipile heap building consists of a belt conveyer (or loader and excavator) that piles the ore into many ore piles with a height of 6.1 miters (or 4 miters ). Then bulldozer is used to bulldozer (or manual rake). During the process of building the heap, the coarse ore will inevitably roll to the side of the heap, and the ore particles in the surface layer of the heap will also be crushed and compacted by the bulldozer. Thus, when the cyanide solution is sprayed from the heap, the ore is crushed and compacted by the bulldozer. The solution permeates through the coarse ore faster than the fine ore resulting in a serious segregation. Or the solution simply can not penetrate into the ore heap and run away from the side flow to wash the heap slope even if part of the solution can infiltrate into the heap. But it is also easy to flow out of the gap, the whole heap can not be evenly leached, so the leaching efficiency is slightly lower.The multilayer layer heap building is to build up a layer of ore with truck or loader, and then bulldozer to smooth it. The layer by layer is built up until constructed. Because each layer of mine is built by truck and bulldozer, the permeability of ore heap is very poor.
The slope heap builging is to construct a slope road with a height of 0.6 ~ 0. 9 m higher than the mine pile to be constructed. The truck unloaded the ore to both sides of the ramp and bulldozed it with a bulldozer (Fig. 3) after the mine was built, the waste rock ramp was levelled. The bulldozer is preferably crawler because its pressure is smaller than the tire. The disadvantage of this heap buiding is that it occupies a large area.
The method of hoisting is to use bridge crane to pile ore and rake it. The advantage of this method is that the ore pile is not compacted mechanically and its permeability is good, and the solution will not be segregated, so the leaching effect is good and the recovery rate is high. But this method needs to set up crane track, the capital construction investment is large, and the heap building speed is slow
