Blockage of ore bearing layers is the most common technical problem in in-situ leaching of uranium. A certain experimental mining area has been operating for about 200 days, and the injection pressure of the injection well has increased to 1.65 MPa, and the average injection flow rate has decreased by 51.87%, and serious blockage has occurred in the surrounding ore-bearing layers. The calculation shows that when the natural flow field conditions are transformed into the leaching flow field conditions, the groundwater flow velocity can be rapidly increased by tens to hundreds of times. Hydraulic erosion is the dynamic condition for the migration and precipitation of debris in the ore-bearing layers around the pumping well. The mineral debris and chemical precipitation carried in the leaching solution, which are retained in the tail liquid after surface filtration and resin bed adsorption, are re-deposited and accumulated in the ore bearing layer around the injection well, which is the direct cause of its blockage. During the research period, mechanical blockage was the main factor, accompanied by chemical precipitation blockage. Based on the research results of the maximum pore throat diameter of previous ore bearing layers, combined with underground television observation, the particle size of the leaching solution, well washing water, and the chemical composition analysis of the settling dry residue of the well washing water, it is determined that the mineral debris is mainly clay powder sand particle level debris, and the chemical precipitation is mainly CaCO3, MgCO3, Fe(OH)3, with a small amount of FeCO3. For this reason, with the goal of “preventing blocking”, a hydrocyclone separator has been added. The surface solid-liquid separation system coupled with “natural sedimentation-hydrocyclone separation-mechanical screening” has achieved obvious results, which is expected to be popularized and applied after further research.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |