1. technical name

Complete technology and application of fine tailings mold bag method for dam construction.

2. scope of application

Fine-grained tailings dam.

3. technical content

3.1 technical principle

By establishing a strength growth mechanism of sand consolidation and water-permeability-extrusion drainage consolidation-constraint molding for processing fine-grained tailings with mold bags, the overall stability of the fine-grained tailings dam is improved and the safe dam construction of fine-grained tailings is achieved.

After the tailings slurry enters the mold bag, water penetrates through the effective pores of the mold bag material to block the tailings in the mold bag, achieving the purpose of sand consolidation and drainage. Under the combined action of the external load of the mold bag and the grouting pressure, the free water is discharged in time, and the tailings in the mold bag are consolidated from free drainage to extrusion drainage. Compared with the traditional dam stacking method, the consolidation time is shortened to 1/4 of the original. The single dam capacity of automatic mold bag filling equipment reaches 1200m3/d.

3.2 main innovations

(1) Innovate a complete set of technologies for dam building with fine tailings mold bag method, achieve safe and efficient dam building of fine tailings, and broaden the application scope of particle size of fine tailings dams.

(2) The mechanism and failure mode of enhancing the stability of the model bag dam are proposed.

(3) The stability control mechanism and process optimization measures for mold bag dam under the coupled action of multiple factors have been established, and on this basis, a new safety and stability evaluation method suitable for fine tailings mold bag dam has been developed.

(4) Developed automatic grading dam building equipment with mold bag method, optimizing the traditional mold bag method dam building process.

4. Pollution control or environmental restoration effects

The sub-dam method is used to pile the mold bag body to change the fine tailings from loose bodies into compacted bodies in the mold bag, and the measured mechanical strength is increased by more than 10%. At the same time, the mold bag dam lengthens the thickness of the dam shell, allowing the most dangerous sliding face to move into the reservoir, and the overall safety and stability of the dam body is improved by more than 30%; the materials used to fill the mold bag all use tailings discharged from the dressing plant or all after adding chemicals. Tailings, and the fine tailings discharged during the process of filling the mold bag are reused after treatment.

5. Technology demonstration

The mining and dressing capacity of the Dapingzhang Tailings Pond of Yunnan Simao Shanshui Copper Co., Ltd. has increased from 1500t/d to 4000t/d. Due to the increase in the production capacity of the dressing plant and changes in the dressing process, the amount of tailings stored in the reservoir has increased, and the average grain size of the tailings has been relatively fine, resulting in small slope of the sediment beach in the reservoir, difficult to control the beach length and safety super-high, and poor safety of the dam body. Problems such as poor safety. Comprehensive safety management measures based on mold bag tailings dam are adopted. The technical route is: mold bag laying → graded (full) tailings filling → squeeze water consolidation of mold bags → mold bag bodies → mold bag body staggered dam stacking to realize Tailings solid waste is safely and environmentally friendly. The volume of mold bag dam is 1000m3~ 1,200 m3/(d·set), and the filling pressure is 0.1MPa~ 0.3MPa. The tailings pond has been operating well since its completion in 2014 and is currently under reclamation.

6. investment estimation

The investment in mold bag filling equipment is about 1 million yuan, which is direct expenses such as equipment material procurement and assembly.

7. investment recovery period

Investment can be recovered in the year when technology is applied.

8. Prospects for transformation and promotion of technological achievements

Compared with the traditional upstream method, the fine-grained tailings mold bag method dam construction technology has the characteristics of fast consolidation of tailings, high utilization rate of tailings, simple construction process, strong site adaptability, and dam construction while producing. It can achieve large-scale dam construction, mature application of technology and strong popularization. It is expected that by 2025, this technology will be promoted and applied in Xizang, Xinjiang, Gansu, Yunnan, Heilongjiang and other provinces.