Abstract:The permeability of the weathered crust elution-deposited rare earth ores directly affects the efficiency of in-situ leaching. The soil-water characteristic curve (SWCC) is an important constitutive relation for calculating the permeability of ore body, which is related to many factors. Soil-water characteristic tests of rare earth ore samples considering different factors were carried out by using the pressure plate instrument. Effects of dry density, particle size and solution leaching on water holding behavior and the mechanism were investigated. The experimental observations indicate that with the decrease of dry density, the pore ratio increases gradually, and the saturated water content increases. Under the same matric suction, the water content decreases gradually with the increase of particle size, thus decreasing water holding capacity of ore accordingly. In the same water content, matric suction is inversely proportional to particle size. Under the same matric suction, the water content of ore samples after leaching is less than that of the ore samples before leaching, indicating that solution leaching can decrease water holding capacity of ore.

Key words: weathered crust elution-deposited rare earth ore; dry density; particle size; solution leaching; soil-water characteristic curve