Uranium resource distribution and accurate reserve evaluation are important references for mineral investment and production. Eight kinds of interpolation methods in the Groundwater Modeling System (GMS), including ordinary kriging (OK), are used in this study to predict the spatial distribution of reserve-related parameters, such as uranium grade, ore thickness and uranium content per square meter. The present study draws the following conclusions: (1) Cross-validation found that the uranium grade value using the spherical method is the closest to the actual value. The spherical method has the best interpolation effect. (2) The relative error, which is +3.62%, between the uranium reserves that is calculated by the spherical interpolation method and that by the traditional calculation value is the smallest. (3) The setting of the number of interpolation grids is related to the actual number of boreholes. The ratio between the two will affect the accuracy of reserve estimation, and different interpolation methods have different degrees of influence on reserve estimation. This method is applicable to all in-situ leaching sandstone uranium mines. Further study needs to be carried out toward heterogeneity of three-dimensional space, which will make the estimation more accurate.

Granite-hosted uranium ores exhibit heterogeneous mineral assemblages and complex pore structures, which may restrict lixiviant accessibility and uranium dissolution during acid leaching. This study investigated a mixed nonionic surfactant system comprising OP-10 and Tween 80 for sulfuric acid leaching of a granite-hosted uranium ore containing 787.5 ppm U. Mineralogical characterization, surface-tension measurements, stirred-leaching and column-leaching experiments, and kinetic modeling were conducted to evaluate the leaching performance. The ore was dominated by quartz, feldspar, and other aluminosilicate minerals, with a heterogeneous pore network. OP-10 exhibited a greater surface-tension-reducing ability than Tween 80, and a 3:1 OP-10/Tween 80 volume ratio was selected. In stirred-leaching tests at 30 °C, a liquid-to-solid ratio of 5.0 mL·g⁻¹, and 20 g·L⁻¹ H₂SO₄, uranium recovery after 10 h increased from 72.4% in the H₂SO₄ system to 87.8% in the mixed-surfactant system. Separate kinetic experiments were conducted at 20 °C and a liquid-to-solid ratio of 2.5 mL·g⁻¹. After 31 d of column leaching, cumulative uranium recoveries were 74.0% and 92.6% for the H₂SO₄-only and mixed-surfactant columns, respectively. Nonlinear first-order fitting yielded apparent rate constants of 0.04176 and 0.06480 d⁻¹, respectively. These column results are descriptive observations because only one independent column was tested per condition. Kinetic model comparisons did not establish a unique rate-controlling mechanism, and the possible contributions of interfacial behavior and solution transport remain to be verified. This study provides experimental evidence for evaluating mixed nonionic surfactants in granite-hosted uranium leaching and offers a basis for further optimization of surfactant-assisted leaching conditions for complex hard-rock uranium ores.