In-Situ Leaching Process for Copper Extraction from Copper Ore

In-situ leaching of copper ore is a hydrometallurgical process in which leaching, concentration, and copper extraction are carried out directly within the underground ore body. This method eliminates the need to extract the ore, significantly reducing capital investment and energy consumption. It is particularly suitable for recovering low-grade, hard-to-mine, and residual ore resources, and the process flow is clear and controllable.

The first step involves ore body pre-treatment. For low-grade underground ore bodies, rock drilling and blasting or stratified caving are employed to create a caving zone with well-developed fractures and good permeability. This creates conditions for leachate infiltration and reaction, ensuring sufficient contact between the leaching agent and copper minerals.

The second step involves the construction of the drilling and leaching system. Injection and collection holes are drilled at the surface or underground to establish a leaching—percolation—collection network. Injection holes deliver the leaching agent, while collection holes gather the copper-rich leachate, creating a stable underground flow field that prevents solution leakage and the spread of contamination.

The third step involves leachant injection and in-situ reaction. The leachant is selected based on the ore type: sulfuric acid solutions are commonly used for copper oxide ores, while copper sulfide ores require the addition of ferrous sulfate, oxygen, or Thiobacillus ferrooxidans to enhance oxidative leaching. The leachant permeates along the fractures, reacting with copper minerals to generate soluble copper ions, thereby transferring copper from the solid phase to the liquid phase.

The fourth step involves the collection and extraction of the rich solution. The copper-containing leachate flows into the collection system under the combined action of gravity and pump suction, is extracted to the surface through extraction holes, and enters the extraction and electrowinning section, where it is separated and purified to produce high-purity cathode copper. The poor solution is treated and returned to the injection system for reuse.

Finally, process control and environmental management are implemented. Flow rate, concentration, pH, and groundwater levels are monitored throughout the process to ensure stable leaching efficiency and recovery rates. Upon completion of leaching, the boreholes are sealed, and the underground area undergoes neutralization and impermeabilization treatment, achieving waste-free mining and green production.

This process eliminates the need for mining, crushing, grinding, and beneficiation, resulting in low investment, minimal pollution, and a short cycle time. It represents a key technological direction for the efficient and green development of low-grade copper deposits.