Heap leaching is used extensively for the processing of low-grade copper and gold ores. If the ore has low permeability, it may lead to underperformance or even project failure. Poor permeability is caused by a high fines content, resulting in a high steady-state moisture hold-up which causes the bed to operate close to saturation. The problem of low permeability can be addressed by either desliming (removal of the fines by wet screening), or by agglomeration (binding the fines together) with a cementitious binder. Fines removal by desliming is shown to reduce the steady-state moisture hold-up, resulting in the bed operating further away from saturation and increasing the maximum solution application rate. Agglomeration with Ordinary Portland Cement modified with additives resulted in fine particles binding together as lumps or coatings onto coarser rocks. These bonds were not destroyed after prolonged exposure to dilute sulphuric acid, due to the pozzolanic properties of the additives (e.g. fly ash), which cause cementitious Ca-bonds to be substituted with more stable Al- or Mg-bonds. Agglomeration with cementitious binder was also found to reduce slumping in leach column tests. This resulted in a higher bed porosity, higher limits on the solution application rate and higher copper dissolution rates. Agglomeration with modified cement may provide a novel, cost-effective method for the treatment of low-permeability ores in acid medium (e.g. copper, uranium and nickel), since cement agglomeration has only been applied commercially in alkali medium (e.g. cyanide solutions for gold ores) to date. Desliming is less attractive due to the high losses of the target metal to the fines.

堆浸广泛用于低品位铜矿石和金矿石的加工。如果矿石渗透率低，可能会导致性能不佳甚至项目失败。渗透性差是由细粉含量高引起的，导致稳态持水率高，导致床层运行接近饱和。低渗透性的问题可以通过脱泥（通过湿筛去除细粉）或通过用水泥粘合剂附聚（将细粉粘合在一起）来解决。通过脱泥去除细粉可以降低稳态水分滞留量，从而使床进一步远离饱和状态并提高最大溶液施用率。用添加剂改性的普通硅酸盐水泥进行团聚，导致细颗粒以块状或涂层形式粘合在一起，附着在较粗的岩石上。由于添加剂（例如飞灰）的火山灰性质，这些键在长时间暴露于稀硫酸后不会被破坏，这会导致水泥钙键被更稳定的铝键或镁键取代。还发现，在浸出柱测试中，用水泥粘合剂进行团聚可以减少坍落度。这导致了更高的床孔隙率、更高的溶液施用速率限制和更高的铜溶解速率。改性水泥团聚可以为在酸性介质（例如铜、铀和镍）中处理低渗透性矿石提供一种新颖的、具有成本效益的方法，因为水泥团聚仅在商业上应用于碱性介质（例如金的氰化物溶液）矿石）至今。由于目标金属在细粉中的损失很大，因此脱泥不太有吸引力。