Full
Outline
In view of the problems of large water inflow and difficult grouting and water plugging in some underground mines in the copper (cobalt) metallogenic belt of Central Africa, which seriously restrict the safe mining of mineral resources, Chambishi Copper Mine was selected as the research object, and efficient plugging materials and processes suitable for this mine and similar water-rich mines were developed. Five kinds of materials, including local clay, bentonite, a chemical material, domestic ultrafine cement and tailings from Africa, were selected for laboratory tests. Multi-proportion slurries were prepared according to different mixing schemes, and the physicochemical properties (viscosity, relative density, bleeding rate and plastic strength), setting time and compressive strength of each slurry's stone body were tested. The results show that the local mud cake meets the requirements for pulping. The 7 d compressive strength of the modified clay slurry stone body is 0.11-0.69 MPa, and its viscosity increases significantly with a decrease in water-solid ratio. It is suitable for large-scale ground curtain, wellbore curtain and other projects, and can reduce material costs by about 30%. The local bentonite meets the requirements for pulping. The 7 d compressive strength of the cement-bentonite slurry stone body is 0.10-2.34 MPa. When the water-solid ratio is ≤2∶1, the setting time shortens with the increase in bentonite content, making it suitable for deep poorly injectable strata. In the deep multi-layer sand belt area, its injectability is 7 times higher than that of traditional cement slurry. The 28 d compressive strength of the ultrafine cement slurry stone body can reach up to 59.8 MPa, and its strength decreases with the increase in water-binder ratio. It is suitable for micro-fracture and backfill grouting, offering improved impermeability and high compressive strength. By adjusting the content of GROUTEX, the chemical slurry can achieve instant setting, and the compressive strength of its stone body reaches 43.65 MPa. It is suitable for sealing poorly sealed boreholes, achieving instant setting with a strength greater than 43 MPa, thereby preventing water inrush accidents caused by exposing water-rich boreholes underground. The bleeding rate of the tailings slurry is high, and the 7 d compressive strength of its stone body reaches up to 9.7 MPa; further improvement tests with different additives are therefore necessary.
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| 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 |
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