Based on suspension of particles and stability of coal slurry in coal transportation pipeline, the calculation formulas for non-silting velocity and resistance loss parameters of coal slurry in pipeline transportation were deduced.The necessity for controlling the maximum particles in coal transportation pipeline was discussed. The verification with the experimental data shows the formulas have high accuracy. Therefore, these formulas can be used in planning
and constructing coal transportation pipelines.

The paper focuses on an introduction of a gas storage tank as a protective measure for water hammer in pipeline transportation of solid materials. According to the principle of reducing the pressure for water hammer, a formula for calculating the gas volume in the gas storage tank was deduced, and the experimental result shows that this formula can provide a high-precision calculation. This gas storage tank have been successfully applied into Shen-Wei coal transportation pipeline, which not only solves the pressure pulsation at the outlet of positive displacement pump,but also solves the problem of water hammer due to negative pressure at the highest point of pipeline along with large downslope, thus playing an important role in ensuring the safe operation of coal transport pipeline.

If the elevation difference between the inlet and outlet of a slurry pipeline system is enough to overcome the hydraulic resistance of slurry pipeline, slurry can be transported with pipelines by gravity. A gravity flow slurry pipeline system has the advantages of low investment and operation costs, as well as being green and eco-friendly.Several successful cases of adopting such system are introduced in this paper, and the key technologies in the design are also analyzed and summarized.

Slurry pipeline transportation technology has become increasingly mature, but process conditions also become more complicated as transportation distance increases. Therefore, multiple pump stations in series are frequently adopted now, and SCADA/DCS system alone cannot meet the requirement of intelligence. The PipelineExpert^TM software can not only visualize the state of pipeline transportation, but also expand its practical functions, such as detection of pipeline blockage and leak, location, batch operation management and warning of accelerated flow, which can provide a more comprehensive guarantee for the safe operation of long-distance pipeline.

A super large copper mine in Tibet is the largest copper mine in Asia with the productivity of 150,000 tons per day. An unreasonable design will bring a profound impact to it. In order to meet the process requirement, coarse and fine flotation tailings are designed to be transported separately by gravity in the early stage of project. For the coarse flotation tailings, a technique consisting of first-stage cyclone, gravity flow, second-stage cyclone and stacking on dam is adopted, while a technique consisting of first-stage cyclone, thickening, and transportation by gravity is adopted for fine-grained flotation tailings. And at a later stage of the project, the treated tailings are transported with a pressurized pipe. It is found that this technique can meet the working condition of centerline tailings dam for coarse tailings, thus achieving a balance in the tailings discharge, as well as cutting operation cost and meeting the requirements for environmental protection.

In order to determine the pipeline resistance during the transportation of tailings slurry in a copper mine,according to the physical and chemical properties of tailings, the rheological properties of the slurry was studied in an experiment by using a rotary viscometer, and the viscosity coefficient and yield stress of the tailings slurry with different mass concentrations were determined. Based on the rheological properties obtained from the test, the critical velocity, flow velocity in the operation and frictional resistance loss were all calculated, and then the calculated results were compared with the measured data in the engineering field. It is found that this method is applicable to fine-grained slurry to a certain extent, and the research results can provide a basis for the design of tailings pipeline transport system.

The rheological properties testing and pipe-loop testing were conducted with tailings slurry of different concentration, for investigating the relationship between pressure loss during the pipeline transportation and slurry concentration and flow velocity, based on the analysis of physical and chemical properties of tailings in Waitoushan Iron Mine. The results show that the critical flow velocity of the tailings won′t change much with the mass concentration. The tailings slurry with mass concentration of 50% is most suitable for long-distance pipeline transportation. And the drag loss was measured to be 107.8 kPa/km during the transportation of the tailings slurry in DN273 pipe at an average flowing velocity of 1.4 m/s.

Hydraulic transportation tests for sediment with different particle size distribution were carried out in pipelines of 300 mm diameter, the influence of particle size fractions on pipe friction was analyzed, and then a four-component friction formula was improved. Based on the combination of 5 different particle sizes of sediment, sediments with 11 kinds of particle size distribution were obtained, and 17 groups of tests were carried out. It is found that with a wide particle size distribution, the peak value in the friction curve appears in the region of higher velocity; an addition of coarse particles to fine particles can significantly increase the pipe friction, while an addition of fine particles to coarse particles at higher flow velocity has little effect on the pipe friction; the mean absolute error between the calculated value obtained by the optimized four-component friction formula and the practical measurement is 5.82%.

Based on the principle of alkali excitation, high concentration fly ash slurry was prepared as filling material with fly ash as the main material, quicklime and cement as activators. The concentration of fly ash was 55%–60%, the bleeding rate of slurry was 1.3%–2.1%, and fly ash and activator was at a ratio of 4.4. The 28-day uniaxial compressive strength of the filling body was 2.87–3.71mpa. The fluidity of the filling slurry was 155–270 mm, the yield stress was 2.61–5.11 Pa, and the viscosity coefficient was 0.029–0.121 Pa?s, which is 1/(2–30) of the relevant parameters of the paste filling material. It shows that this slurry, presenting excellent flow characteristics, can greatly reduce the resistance loss of pipeline. Based on Bernoulli's equation, the characteristics of energy conversion and the determination method of pipeline resistance loss of gravity transportation system were analyzed, and a feasibility analysis process was presented for the gravity transportation of filling slurry. Based on the research, the gravity flow transportation of high concentration fly ash filling material with the backfilling gradient of 7.6 was designed for Shenzhou Coal Industry Co., Ltd. and has been successfully put into use.

The identification, the harm and the measures of accelerated flow in slurry pipeline were analyzed. Based on the flow variation and discharge points of slurry pipeline transportation in a mine, four commonly used energy dissipation measures, namely, increasing route, reducing pipe diameter, energy dissipation of water drops and choke energy dissipation, were qualitatively and quantitatively analyzed in terms of adjustment capacity, operation management and investment, and the choke station for energy dissipation that was finally determined to be more suitable for this project.

A real-time warning system has been verified and used for pipeline blockage in order to ensure the continuity, stability and high efficiency of slurry pipeline transportation. Based on the long-time monitoring of the pipeline transportation characteristics and blockage analysis, the pressure, flow and concentration change law during the pipe blocking process were explored, and a complete set of equipment and technology have been developed for real-time warning of blockage. It is found that when the pipe blockage occurs, there exists an abrupt change in both pressure and flow, and the spreading rate of abrupt change in pressure is in consistence with the advancing speed of slurry. Then, a real-time warning system, established based on the variation characteristics of flow speed and fluid concentration in the blocked pipe and the spreading rate of the abrupt change in the pipe pressure, can be adopted to real-time predict the blockage location, with the maximum error of 5%.

With focus on the progress in slurry pipeline construction, standard systems and theoretical research of transportation technologies in China, combined with the development of domestic oil and gas pipeline, the construction and development trend of slurry pipeline are analyzed. Coal slurry pipeline in China has a wider potential market in the future. The localization process of key equipment, materials and software is accelerated for slurry pipeline, and the market share is gradually increased. Based on the experience of oil and gas pipeline development, the concepts of digitization and intelligence have become an inevitable trend for slurry pipeline system.

For river and lake dredging engineering project, a fabricated cutter-suction dredger with small diameter pipeline has a shortcoming of insufficient discharge distance, and the traditional relay pump has not only difficulty in installation and maintenance, but also high operating cost. In order to alleviate those shortcomings, an experimental study was carried out with small diameter sludge discharge pipes of DN400 under various working conditions. The results show that gas-water jet can lead to pressure increase, drag reduction and increase of discharge distance. The optimal process is as follows: gas-water mixture is jetted through a jet pipe preferably with a diameter of DN32, from the top part of pipeline about 150m away from the outlet of dredge pump with a vertical incident angle. And the jet gas pressure is about 0.27–0.32 MPa higher than the pressure in the pipe, and the jet water pressure can be set around 0.6 MPa. Compared to the traditional relay pumping operation, the discharge distance can be increased by about 16.4% under the optimal process parameters. This research result can provide reference for the construction of cutter suction dredger with small diameter pipeline with long discharge distance.

In order to optimize the technical parameters of air pressure to boost pipeline transportation, a numerical simulation of characteristics of pipeline transportation under different air pressure was carried out. Based on an experiment of transportation with DN300 steel pipe by ejecting air, a mathematical model for pipeline transportation under different air pressure was established and verified, and the influence of different air pressure on boosting pipeline transportation were also explored. The results show that as air pressure increases, the pressure, velocity and turbulent kinetic energy in the pipeline increase accordingly, which will inhibit the pipeline transportation of clean water after an initial boosting effect, showing there is an optimal critical air pressure. With air pressure of 120 kPa, the pressure in pipeline can be increased by 0.5% and drag reduced by 9.74%, which can bring a good pipeline transportation performance.

When a slurry pipeline in mountainous area is shut down, the solids in the pipeline will settle. Part of solids will slide to the low point, forming a plug, if the slope of the section is greater than the angle of repose of the solids in water. When the movement resistance of the plug is greater than the driving force of the system, the pipeline is defined as blocked. The upper part of the plug is usually watery or soft, which can yield to form a channel under sufficient pressure difference and make it possible to unblock the pipeline. Phosphogypsum slurry contains colloidal compound, which can make the plug solidified with time. Spare equipment must be taken into consideration in the pipeline engineering for this type of slurry, so as to minimize shutdowns and shorten the down time.

An introduction of flexible composite hose adopted in the pipeline transportation of tailings in a mine and the tailings discharge in the tailings pond is presented in terms of its material, structure and characteristics. It is concluded that the flexible composite hoses will partially replace steel pipes in slurry pipeline transportation and have wide application prospects.

Erosion-corrosion resistant steel (BMS1400) with 450 HBW hardness was developed to meet high erosion-corrosion requirement for dredge pipes. The steel sheet, designed with principle of depressing corrosion and improving wear resistance, has excellent formability, low-temperature toughness and erosion-corrosion resistance. The effect of heat treatment process on mechanical properties of steel sheets was analyzed. The dredge pipes with BMS1400 steel were successfully manufactured with the problems of poor dimensional accuracy and the likelihood of weld cracking solved by optimizing plate rolling and welding technique. Practical testing indicates that the large diameter dredge pipes fabricated with BMS1400 sheet steel have good ellipticity and flatness, both up to the design requirement. BMS1400 steel pipes have been successfully applied in dredging for several times, showing the pipes has two times the erosion-corrosion resistance of the pipes fabricated with carbon steel.

In order to prolong the service life of rubber hose of dredger, a new type of rubber hose with inner wall covered with metals was developed based on the analysis of various problems encountered in the actual use of the existing rubber hose. Comparied with the existing rubber hose, the rubber hose with inner wall covered with metals can have a prolonged service life under harsh working conditions, such as transportation through acute-angled coral reefs, medium-coarse sands and rocks, thus it can bring good economic benefits.

A new type of thermoplastic hose for mortar conveying is introduced at first. The adopted hose is a steel wire reinforced thermoplastics composite pipe, with the wear-resistant layer made of polyolefin wear-resistant material GXXG-1101, the middle layer reinforced by steel wire, and the outer sheath made of special elastomer material. Thus, this hose can not only overcome the shortcoming of inflexibility of PE composite wear-resistant pipe, but also overcome the disadvantages of traditional rubber conveying pipe, such as un-recyclability, short service life, high density and product with fixed length. As a result, it has found wide application. Based on the comparison experiment on the wear during the mortar conveying, it is concluded that the new thermoplastic wear-resistant hose is superior to the traditional rubber conveying pipe.

In consideration of the location of head end pulping plant in Shenmu Hongliulin Coal Mine and the convenience of taking mine water, the mine water in Hongliulin Coal Mine is planned to be used as the second water source for coal transportation. In the study, based on the preparation of coal pulp with mass concentration of 53%, the variations in the water quality indexes were compared and analyzed by using Fugu incoming water and Hongliulin mine water in coal transportation. The influencing factors for the corrosion and scaling were also analyzed, which can provide some theoretical guidance and suggestions for the following optimal water used in coal transportation. The analysis result shows that both Fugu water and Hongliulin mine water are weakly alkaline, and the ion content before and after pulping is relatively lower, which has little impact on the corrosion. However, key factors such as conductivity and Cl^- content should be taken into the consideration for the corrosion of the pipeline during long-term operation.

Barun Mining Company of Baotou Iron and Steel Company has its iron concentrate processed by six private concentrators. In order to cut high cost for road transportation of iron concentrate and solve the related environmental issue, Barun Mining Company plans to carry out pipeline transformation for the transportation of iron concentrate slurry from private concentrators. Based on research and efforts for tackling key problems, innovative technology has been developed to realize online accurate measurement for slurry pipeline transportation.

Based on the physical model of G J Kench, a non-Newtonian Bingham body yield stress and a static settlement curve of slurry were obtained by performing slurry rheological test and static settlement test in a measuring cylinder. The type of thickener can be selected according to slurry yield stress. Based on the analysis of the static settlement curve, it is proposed that the secant method for index correction can be used to calculate the area and diameter of thickener. It is found that the calculated results are close to the actual operating area and diameter of the thickener used in the pretreatment for the 135-kilometer slurry pipeline transportation in Ramu Nickel Project of Papua New Guinea, which proves this method can be used as a reference for design.

The coal gangue in Zhungeer coalfield is rich in kaolinite, and there is a small part of gangue coal, which is still worth comprehensive utilization. For the purpose of comprehensive utilization and underground backfilling of coal gangue in coal mine, a process consisting of“selective crushing, multiple size screening and pumping of large-size particles”was adopted to realize the classification of coal gangue. Then, environmentally friendly treatment and backfilling process were taken for different areas, so as to ensure coal gangue in the underground coal mine treated in a scientific way and reduce the comprehensive treatment cost. It is found to be beneficial to comprehensive environmental protection, energy conservation, as well as emission reduction.

Aiming at the problems of high turbidity, short service life of pump and low water treatment efficiency caused by high solid content of mining wastewater, flocculation settlement experiment was carried out. Firstly, the relationship between the residence time of wastewater in the clarification tank and the standard flocculation sedimentation time was determined based on the theoretical analysis and similar principles, and a calculation model for the dosage of flocculant was established. Secondly, the model parameters were determined based on the laboratory wastewater sedimentation experiments. Finally, the rationality of the model was verified through the material balance.The results show that the turbidity of wastewater can be reduced to 30NTU after flocculation and settlement with the dosage of flocculant calculated by the model, and the service life of water pump and the efficiency of wastewater treatment can be improved.

With Shenwei coal pipeline transportation project taken for research, the variation law of water quality was investigated by performing a simulation test of coal slurry during the transportation. It is found that the suspended solids, COD, salt content and total hardness of the transported slurry increase, while the total alkalinity decreases. The variation law and causes of variation for the conventional indicators such as suspended solids, chemical oxygen demand, salt content, total hardness and total alkalinity of the slurry during long-distance transportation were analyzed.The research result can provide some guidance for the treatment of process water at the head end of coal transportation pipeline and coal slurry dewatering at the terminal.

The design parameters of pipeline and electric lift pump were analyzed separately for solving problems existing in vertical pumping and conveying pipeline system in deep-sea mining. An optimal design for the pumping and conveying system was prepared for the polymetallic nodule mining project in the South China Sea. Based on the available experimental results and numerical simulation results, the internal diameter of the pipeline and flow velocity of conveyed slurry with different volume concentrations were calculated, and the pressure loss in the conveying pipeline with different process parameters was then obtained. With the pipeline parameters taken into consideration, the electric lift pumps with different number of stages and speed were designed. The specific speed, efficiency and power of the electric lift pump under different design concept were calculated with empirical formulas, which can provide some theoretical basis for the design optimization of electric lift pumps.

Deep sea tailings placement (DSTP) is an environmental friendly tailings storage method. Once the mining activities stop, sediments from nearby rivers will cover the tailings. The ecosystem can be restored fast. DSTP system includes tailings neutralization, transportation, dilution, deaeration and deposition. The design philosophy of the DSTP system is introduced in this paper including the simulation of hydrodynamic behavior of tailings in deep sea environment.

At the Ansys Workbench platform, a 3D model of lift pump impeller was established by using the CFturbo software. Then, CFD numerical simulation was performed with CFX, and the simulation results was compared with the test results to verify the finite element model. With the inlet diameter, outlet width, outlet diameter, blade outlet placement angle, and blade wrap angle of the impeller as the variables in discrete design, and with the head, efficiency and flow area of the impeller as the optimization targets, the design of lift pump impeller was optimized based on a neural network. The results show that this method is more efficient and accurate, and an ideal effect can be obtained after optimization.

The design and operation of leakage and blockage detection system in tailings slurry transportation pipeline are introduced. Based on the negative pressure wave and measurement shortage analysis, the detection system achieves a real-time data communication through the fiber optical LAN. The practice has proven that this system is feasible, and the operation is stable and reliable.