Aiming at the significant variation in clay content within the orebody of the Letpadaung copper mine in Monywa, Myanmar, this study conducted comprehensive research on ore classification based on clay content and its impact on bio-heap leaching performance. Pressure filtration tests confirmed that clay content is a critical factor affecting ore permeability and copper leaching efficiency. Accordingly, a classification standard centered on clay content was established based on the ore properties of the Letpadaung Copper Mine, categorizing the ore into four types: low-clay ore (25%). Corresponding differentiated stacking strategies were proposed and applied for the first time in industrial operations at a scale of several hundred thousand tons. Industrial practice results demonstrated that, compared with the unclassified mixed ore with a leaching efficiency of 45.92%, the implementation of classified heap leaching increased the copper leaching rates of low-clay ore and medium-to-high-clay ore to 68.07% and 63.41%, respectively. Moreover, multi-layer heap leaching within the same leaching unit showed consistent leaching efficiency across different layers after ore classification. These results further validate that ore classification based on clay content combined with differentiated heap leaching processes serves as a vital technical approach for ensuring efficient and stable heap leaching operations at the Letpadaung copper mine.
Wang et al. (2026) studied this question.