The Recent Progress China Has Made in the Backfill Mining Method, Part I: The Theory and Equipment of Backfill Pipeline Transportation
Abstract
:1. Introduction and Background
- (1)
- The research on filling slurry transportation theory undoubtedly has a very positive impact on mining production and filling efficiency, and in recent decades, engineering researchers from China have been doing research in this direction.
- (2)
- The research on the performance of backfill pipelines in China has always been the core of the development of China’s mining industry.
- (3)
- Led by Fei-Yi Corporation, China’s major mining equipment manufacturing companies have been vigorously developing mining equipment in the past decade.
- (1)
- Progress of the theory of backfill pipeline transportation in China;
- (2)
- Progress of the equipment of backfill mining method in China.
2. Development of the Theory of Backfill Pipeline Transportation in China
2.1. Introduction and Retrospective: Theory of Solid–Liquid Two-Phase Flow Filling Slurry Pipeline
2.1.1. Rheological Model of Solid–Liquid Two-Phase Flow
- A.
- Bingham Plastic Body
- B.
- Pseudo-Plastic Body
- C.
- Expansion Body (The Expansion of Body)
- D.
- Pseudo-Plastic Body with Yield Stress
2.1.2. Pipe Flow Characteristics of Heterogeneous-Homogeneous Composite Two-Phase Flow
2.2. The Progress of the Calculation Methods of Conveying Resistance of Solid–Liquid Two-Phase Flow Pipeline in China
2.2.1. Jinchuan Formula (from China)
2.2.2. Formula of Changsha Research Institute of Mining and Metallurgy (from China)
2.2.3. Anshan Mine Design Institute Formula (from China)
2.2.4. Formula of Beijing General Institute of Design and Research of Nonferrous
Metallurgy (from China)
3. The Equipment of Backfill Mining Method in China
3.1. Retrospective: Reliability Countermeasures of Filling Pipeline Conveying System
3.1.1. Study on Pipeline Wear Mechanism
3.1.2. Analysis of the Main Influencing Factors of Pipeline Wear
- (1)
- The factor of filling slurry. Pipeline wear is caused by conveying filling slurry, so it must be related to the filling slurry [35,36]. Firstly, the wear velocity of the pipe increases with the increase of packing slurry concentration, which is mainly manifested in the wear of horizontal pipes. Secondly, pipeline wear increases with the increase of aggregate stiffness and particle size [37]. For example, the wear rate of rod grinding slurry with larger conveying stiffness and particle size is higher than that of tailings filling slurry, and this wear performance runs through the whole line of the pipeline [38]. Thirdly, the pipe wear increases with the irregular shape of the filling aggregate particles, and the wear of the bar sand with sharp edges is more serious than that of the smooth spherical river sand. Finally, the erosion of the pipeline increases with the increase of the corrosiveness of the filling slurry [39].
- (2)
- The factor of pipeline. When using the same backfill materials, the pipeline wear is closely related to the selected pipeline material. Usually, the service life of a high-quality pipe is several times or tens of times that of an ordinary pipe; the life of the pipe is also related to the thickness of the pipe wall. The thicker the pipe wall, the longer the service life. The wear rate of the pipe is also closely related to the pipe diameter [40].
- (3)
- The factor of filling times line. Filling times line is also an important factor affecting pipeline wear. The smaller the filling times line is, the higher the height of the free fall area in the vertical pipe is, the greater the impact force of the slurry on the pipe is, and the more serious the pipe wear is [41,42]. At the same time, when the flow velocity of slurry increases, the wear rate increases, the filling times line decreases, the pipeline pressure increases, and the wear rate increases. In addition, reducing the filling times line will also cause excessive residual pressure at the slurry outlet, severe vibration of the pipeline, and serious damage to the pipeline [43,44].
3.1.3. Technical Ways to Reduce Pipeline Wear
- (1)
- Reduce abrasion of slurry on pipeline.
- (2)
- The full pipe flow conveying system is adopted, to reduce the impact force of slurry on the pipe wall in the vertical pipe.
- (3)
- The step-down conveying system is adopted, to reduce the pressure of slurry on the pipe wall.
- (4)
- Improve the installation quality of vertical pipelines and reduce the inclination and non-concentric degree of pipelines.
- (5)
- In the mine with small filling times line, it is necessary to reduce the conveying speed of the slurry and reduce the wear of pipeline.
- (6)
- In the elbow part with high wear rate, the cross pipe or buffer box elbow should be used to avoid the narrow and long groove that the slurry grinds out of the outer radius of the large diameter elbow.
- (7)
- Comprehensively improve the manufacturing quality of steel pipe lining, ensure the quality of lining and coating, and prevent the lining from loosened out with the slurry.
- (8)
- Use neutral water to prepare the filling slurry and flush pipes and avoid using highly corrosive mine water.
3.2. Introduction: Filling Slurry Pipeline Conveying Equipment Products in China
Wear Resistant Filling Pipe
- (1)
- Pipe of Single Material.
- (2)
- Ceramic Composite Pipe.
- (3)
- Bimetal Composite Wear-Resisting Pipe.
- i.
- The composite process of epc vacuum casting adopts polystyrene plastic foam to make the lining model and put it into the steel pipe. After coating, drying, and molding, the high alloy wear-resisting material is poured at high temperature under vacuum conditions; the plastic foam is decomposed and vaporized at high temperature and is replaced by the alloy liquid in situ. After cooling and solidification, the outer layer is a steel pipe, and the inner layer is a bimetal composite pipe with high wear-resistant alloy.
- ii.
- Automatic centrifugal casting composite process. The steel pipe is fixed in the special pipe mold in a state of high-speed rotation, using a fan-shaped bag, long flow grooves, and other flow pouring principles; by controlling the pouring speed and pouring temperature, the high wear resistant alloy liquid is poured into the steel pipe, so that under the action of centrifugal force, there is uniform distribution on the inner wall of the steel pipe.
- (4)
- Ultra-High Molecular Polyurethane Composite Wear-Resistant Pipe.
3.3. Introduction: The Filling Pump in Chin
3.3.1. Tow Type Concrete Pump
3.3.2. Filling Industrial Pump: The Comparison between German Products and Chinese Products
- (1)
- Germany Putzmeister Company Filling Industrial Pump
- (2)
- Filling Industrial Pump of Fei-Yi Co., LTD. (China)
- i.
- Hydraulic system: High reliability, small reversing impact, low oil temperature, hydraulic system, oil self-cleaning ability; double pump, combined flow hydraulic system, and constant power control, make the system more simple, more reliable; the unique parallel synchronous control hydraulic technology of large diameter valve slide effectively solves the problem of reversing of the hydraulic system with large flow [52].
- ii.
- Pumping system: Hopper through the new design, double side door type, easy maintenance and cleaning. Double stirring feeding mechanism, excellent suction. Adopt high strength wear-resisting steel plate durable. Completely remove dead material, no aggregate, pump material fluidity and absorption are greatly improved; long working stroke of pumping mechanism, system balance, small impact, low pumping frequency; the imported piston sealing body has good wear resistance and greatly improves the service life; cylinder piston adopts imported metal ring seal, and the durability is greatly improved.
- iii.
- Power system: The dual power combination system is adopted. The two power units are the same as each other. They are on standby for each other and work in parallel or independently, which further improves controllable reliability and versatility. Hydraulic power components and control components are of high reliability; stable operation of the system.
- iv.
- Electric control system: Adopting high-performance electronic components and a programmable controller; computer central integrated control, realizing equipment operation, interlocking, proximity protection, and peripheral synchronous control.
- v.
- Cooling system: There are two filters and one air cooler in parallel in the oil return circuit of each main reversing valve, which work independently of each other. When the oil temperature is too low, it is mainly filtered; when the oil temperature is high, it is mainly cooled and automatically adjusted.
- vi.
- Lubrication system: Central automatic lubrication system, with automatic lubrication, running indicator, light, low liquid level alarm, fault alarm, adjustable flow, temporary trigger, and other functions; stable and reliable performance.
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
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Series | Conveying Medium Concentration (%) | Maximum Throughput (m3/h) | Maximum Pumping Pressure (MPa) | The Largest Size (mm) |
---|---|---|---|---|
KOS | 50~85 | 400 | 14~15 | 50 |
HSP | 40~70 | 400 | 15 | 10 |
KOV | 40~50 | 40 | 15 | 1 |
EKO | 60~90 | 14 | 6 | 100 |
Equipment Model | The Biggest Processing (m3/h) | Maximum Pumping Pressure (MPa) | Pump Discharge Size (mm) | Motor the Forehead Rated Power (kW) | Working Device Overall Dimensions (mm) | Dynamic Part Overall Dimensions (mm) |
---|---|---|---|---|---|---|
HGBS110.14.500 | 113.8 | 14.2 | 180 | 500 | 7855 × 2103 × 1580 | 4600 × 2750 × 2195 |
HGBS120.09.220 | 121.1 | 9.1 | 180 | 220 | 7056 × 2103 × 1605 | 4100 × 2062 × 2195 |
HGBS140.08.264 | 137.8 | 8.0 | 180 | 264 | 7855 × 2103 × 1605 | 4100 × 2062 × 2195 |
HGBS160.14.800 | 155.8 | 14.2 | 200 | 800 | 9055 × 2103 × 1580 | 5000 × 2750 × 2195 |
HGBS210.14.800 | 207.2 | 14.2 | 200 | 800 | 9055 × 2103 × 1590 | 5250 × 2750 × 2195 |
HGBS350.12.1260 | 350.0 | 12.5 | 320 | 1260 | 10,744 × 2353 × 1865 | 4775 × 2750 × 2195 |
HGBSQ450.14.1890 | 448.4 | 14.2 | 400 | 1890 | 10,760 × 3020 × 2244 | 7300 × 4343 × 2964 |
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Yu, H.; Li, S.; Wang, X. The Recent Progress China Has Made in the Backfill Mining Method, Part I: The Theory and Equipment of Backfill Pipeline Transportation. Minerals 2021, 11, 1274. https://0-doi-org.brum.beds.ac.uk/10.3390/min11111274
Yu H, Li S, Wang X. The Recent Progress China Has Made in the Backfill Mining Method, Part I: The Theory and Equipment of Backfill Pipeline Transportation. Minerals. 2021; 11(11):1274. https://0-doi-org.brum.beds.ac.uk/10.3390/min11111274
Chicago/Turabian StyleYu, Haoxuan, Shuai Li, and Xinmin Wang. 2021. "The Recent Progress China Has Made in the Backfill Mining Method, Part I: The Theory and Equipment of Backfill Pipeline Transportation" Minerals 11, no. 11: 1274. https://0-doi-org.brum.beds.ac.uk/10.3390/min11111274