Drainage Technology Research Articles

Calculation Model of Multi-Well Siphoning and Its Feasibility Analysis of Discharging the Groundwater in Soft Soil

The use of a siphon is a drainage method that does not require the use of external power, and siphons are used extensively in practice. The application of siphons in the treatment of soft soils has become a popular approach in recent years. Analyzing the change in the water level in multi-well siphoning is the basis of the application of siphons. The calculation model of multi-well siphoning is established through equivalent transformation. A finite difference method is used to solve the model, and the accuracy is verified by comparing the results with a test of the model and with field tests. Using the numerical model, the feasibility of siphoning drainage in soft soil is demonstrated from two aspects, i.e., well spacing and the permeability coefficient. The results show both the “minimum drop increase” and the “average drop increase”, as well as the spacing of the decreases or increases in the permeability coefficient. When the permeability coefficient is 1 × 10−8 m/s and the well spacing is 2 m, the decrease in the water level is approximately 9.72 m after 100 days of drainage. It is feasible to apply siphon drainage technology to discharge the groundwater in soft soil.

Sustainable Drainage Technologies Under the Sustainability Tripod Perspective

The management of drainage and urban rainwater management in Brazil and in the world faces numerous challenges in order to be sustainable. When dealing with sustainability, it is important to relate the aspects: of social, environmental and economic, known as the sustainability tripod. Compensatory urban drainage techniques, through infiltration or detention and increasing the evapotranspiration rate, have the potential to reduce: the amount of rainwater runoff; flow peaks; vulnerability of urban areas to flooding; contamination of water courses. It is important that, even with all these benefits, such technologies are associated with such aspects. In this context, this systematic review article (SR) was developed, which aimed to identify trends in the use of sustainable drainage technologies adopted in Brazil and in the world, relating them to aspects of sustainability. For that, a systematic review (SR) was carried out in which the following were identified: trends in the adoption of technologies for sustainable drainage in the world and in Brazil; and the terms used and related to technologies for sustainable drainage. It was also observed, both in Brazil and in the world, that the approach to the theme begins with the technological aspect involving the implementation, life cycle and maintenance of sustainable technologies and, in sequence, the environmental, economic and social aspects unfold in this order, but which are not done in an integral way. It was possible to characterize an important knowledge gap.

The Law of Liquid–Solid Carrying in the Wellbore of Natural Gas Hydrate Gas Well under the Condition of Foam Drainage Gas Recovery

During the trial production of marine gas hydrate in the former Soviet Union, Canada, North Slope of Alaska, South Sea Trough of Japan and Shenhu Sea of South China Sea, the problem of sand and water production cannot be avoided. The problems of sand production and water production in the process of natural gas hydrate depressurization exploitation have seriously restricted the exploitation efficiency and production of natural gas hydrate. The problems of sand production and water production are some of the main factors that prevent natural gas hydrate being commercially exploited. Therefore, it is urgent to carry out useful, relevant and cutting-edge research on the efficient drainage of sand and water from the wellbore in the process of natural gas hydrate mining. This paper innovatively proposes liquid-carrying and solid-carrying technology under foam circulation purging to address the existing problems of sand removal and drainage technology in hydrate mining. At present, no scholar has used this technology to solve the problem of sand removal and drainage in hydrate mining. Therefore, the research on efficient drainage is imperative. In this paper, We mainly studied the liquid-carrying and solid-carrying of vertical wellbore under the condition of foam cycle purging. We have revealed the relevant the liquid-carrying law and solid-carrying law through the above research.

Ecological water security impact of large coal base development and its protection

The two main factors of groundwater system disturbance in coal mines are mine water inflow caused by overburden destruction and advance drainage projects as the main means of mine water hazard control. An urgent problem to be solved in the ecologically fragile area is how to minimize the impact of advance drainage on the groundwater ecological environment while reducing mine water inflow rate to ensure safe production. This paper proposes an optimal advance drainage technology based on multi-objective groundwater management. Based on the analysis of the respective relationship between the drainage groundwater level and the capture supply and mine water inflow rate, the concept and mathematical expression of the drainage threshold of the mine and the ecological environment are put forward for the first time. Based on the numerical simulation model, this technology fully describes the dynamic changes of the groundwater system and establishes a groundwater management model with multi-objective constraints such as mine production safety, ecological water resources protection and efficient drainage. The optimal drainage scheme for the boreholes location, the drainage volume and the time distribution is obtained through objective programming. While reducing drainage volume and ensuring mine production safety, the impact on the locally important phreatic groundwater is significantly reduced, effectively resolving the contradiction between ecological water resource protection and mine safety production. In the example of a coal mine in Northwest China, by comparing the traditional equal drainage scheme, the optimized advance drainage technology fully considers the water-richness characteristics and the dynamic changes of the groundwater system during the drainage process. The number of boreholes in the optimization scheme is reduced by 50 %, and the total drainage volume is reduced by 40.60 %. More importantly, under the condition that the decrease of mine water inflow rate in the two schemes is basically the same, the average increase of Quaternary leakage in the optimization scheme decreases by 53.36 %. Through this technology, the ecological critical value in the study area is evaluated. When the regional Quaternary groundwater level decreases by more than 0.73 m, the impact range of the drawdown funnel and the drawdown rate are obviously accelerated. It provides a scientific foundation for groundwater resource management and low-carbon mining in ecologically fragile areas.

Study on time–space characteristics of gas drainage in advanced self‐pressure‐relief area of the stope

AbstractGas drainage is an important measure to ensure energy safety in coal mines. However, for mines with high gas content and low permeability, the critical question is how to enhance the drainage effect of drilling. By using the self‐unloading pressure effect on the coal body in front of the mine, the permeability of the coal body can be improved, which facilitates gas drainage. Therefore, establishing the fluid–solid model of gas‐bearing coal mass under the influence of mining, this paper simulates the advanced self‐pressure‐relief range in front of the coal working face and the permeability of coal seam at different heights. Through simulations and field tests, the reasonableness of the advanced self‐pressure‐relief gas drainage was verified, and the spatial and temporal characteristics of the gas drainage from the borehole were quantified and analyzed. The results show that the width of the advanced self‐pressure‐relief zone after simulated mining is 25 m, the vertical permeability of the coal seam increases first and then decreases with the increase of the height from the floor, and the maximum permeability of the layer is 2.6 m from the floor, which is 8.62 times higher than the initial permeability; the gas drainage effect of test boreholes has a periodic law with the coal seam recovery, which, divided into the initial drainage stage, the scalar volume of gas drainage increase stage, and the scalar volume of gas drainage decay stage. At a distance from the working face 20–40 m, the boreholes' scalar volume of gas drainage increased by 3.89 times compared with the initial drainage stage, and the scalar drainage volume of the boreholes through the seam increased by 8.01 times compared with the initial drainage stage; in the section of increasing scalar volume of drainage, the gas drainage volume of the boreholes at different heights of the coal seam had obvious “stratification” phenomenon. The test boreholes were optimally placed in the middle of the seam at the lower end. The study provides a reference for self‐pressure‐relief gas drainage technology and optimization of borehole placement.

Study on Key Parameter Design and Adaptability Technology of the 110 Mining Method for the Yuwang NO.1 Coal Mine in the Diandong Mining Area

The 110 mining method is a high-efficiency entry-retaining technology without coal pillars or filling materials. At present, there is no precedent for its application in the Huaneng Group. In order to introduce this technology, it is planned to carry out experimental application research in the Yuwang NO.1 Coal Mine of the Huaneng Diandong mining area. The Yuwang NO.1 Coal Mine is a typical coal and gas outburst mine with a coal seam group. In view of the introduction of the 110 mining method under these conditions, first, the geological conditions of the Yuwang NO.1 Coal Mine in the Huaneng Diandong mining area are analyzed, the geological characteristics of the test mining face are summarized, and the practical feasibility of the 110 mining method is analyzed according to the geological characteristics of “one soft, one low, two high, and two complex”. Then, according to the engineering experience, calculations, and analysis, the key parameters of roof cutting of the test mining face in the Yuwang NO.1 Coal Mine are obtained, and with the help of a numerical simulation, the roof-cutting height, the roof-cutting angle, and the blasting parameters are numerically simulated and analyzed. The roof-cutting key parameters of the test face are obtained as follows: the roof-cutting depth is 7 m, the roof-cutting angle is 15°, and the blasting method is continuous hole blasting with 500 mm spacing. After that, according to the coal and gas outburst and the occurrence conditions of coal seams in the Yuwang NO.1 Coal Mine, a variety of gob closure design schemes and gob gas drainage design schemes are put forward, and the field effect investigation scheme is given. After the tunnels and open-off cut of the test coal mine’s first mining face are connected, under the guidance of the above research results, the field blasting test and the 110 mining method entry-retaining test are further carried out to verify the rationality of the design of the roof-cutting parameters and the feasibility of the gangue wall closure and gas drainage design. Furthermore, in the process of the field practice, continuous research is carried out on the stope pressure law and the adjacent layer gas drainage technology under the 110 mining method, and finally, the 110 mining method application technology system in the Diandong Mining Area is formed.

Study on Gas Drainage Technology in Goaf of Steep Seam

Aiming at the problem of gas control in the upper corner of steeply inclined coal seam, taking 3103 working face of a mine as an example, this paper determines the height range of fracture zone by combining theoretical empirical formula with on-site investigation of microseismic monitoring technology, designs the parameters of drainage borehole during production, and analyzes the gas drainage effect of long-strike borehole through on-site experiments. The results show that the average gas extraction concentration of the long borehole along the strike of 3103 working face is 53.55%, and the average gas extraction purity is 5.37 m3/min. After treatment, the gas concentration in the upper corner is about 0.4%, and the concentration in the return air roadway is about 0.3%, which ensures the control effect of gas extraction quantity.

Modeling optimization for a typical VOCs thermal conversion process

Aiming at the current environmental problems, the thermal oxidation treatment for industrial VOCs emission is a common and effective measure. This paper studies on the optimization effect of one optimization method for direct VOCs thermal oxidation of a color aluminum spraying production line based on Aspen-Plus. According to the direct VOCs thermal oxidation process with a 30000 m³/h circulating air volume, propose the flue gas reflux and coating room drainage technology. Use the second law of thermodynamics, and the exergy flow analysis shows the methane consumption could be reduced 12%. Carbon emissions also decreased significantly, with 3.42% reduction. These findings are practical for industrial production cost saving and environmental protection problems solving.

Adsorption kinetics investigation of surfactant molecules at the short-chain alkane-water interface

Foam drainage technology based on surfactants is considered the most promising measure to solve liquid accumulation in natural gas wells and gathering pipelines. However, the presence of multiple alkane components in condensate and natural gas will affect the properties of aqueous foam containing surfactants, which greatly limits the application of this technology. To clarify the mechanisms of different condensate oil and natural gas components on foam properties, the interface characteristics of different alkane-surfactant-water systems were systematically analyzed from thermodynamics and kinetics by molecular dynamics simulation and experimental methods. The results show that the interfacial adsorption of alkanes and the interaction between alkanes and surfactants are the main factors affecting the surface tension and stability of interfacial films of different systems. This study has guiding significance and reference value for foam drainage in oil and gas fields.

Low-Sloped Rooftop Storm-Water Detention Assembly to Mitigate Urban Flooding

Low-sloped roofs such as commercial and high-rise buildings in a dense urban area provide vast “unused” surfaces that can be used to manage storm-water and mitigate urban flooding. Storm-water Detention Assembly (SDA) known as “blue roof” exerts advanced drainage technologies and operational strategies to store-and-release storm-water during and after heavy rainfall events. SDA can reduce peak flow and decrease storm-water run-off volume. However, the SDA application is limited due to the lack of science-based regulatory requirements. This paper introduces SDA, summarizes the benefits and challenges of this system, reviews the existing code specifications on roofing drain systems, and documents the criteria to design and construct SDA. With this systematic approach, the missing links are identified that shall form code change request for possible inclusion in the National Building Code of Canada (NBCC) and National Plumping Code of Canada (NPC). In addition, a road map is stated to calculate and benchmark the drain requirements on low-sloped roofs for a given design climatic load.

Quantitative Identification of Water Sources of Coalbed Methane Wells, Based on the Hydrogen and Oxygen Isotopes of Produced Water—A Case of the Zhijin Block, South China

The quantitative identification of water sources is an important prerequisite for objectively evaluating the degree of aquifer interference and predicting the production potential of coalbed methane (CBM) wells. However, this issue has not been solved yet, and water sources are far from being completely understood. Stable water isotopes are important carriers of water source information, which can be used to identify the water sources for CBM wells. Taking the Zhijin block in the Western Guizhou Province as an example, the produced water samples were collected from CBM wells. The relationships between the stable isotopic compositions of the produced water samples and the production data were quantitatively analyzed. The following main conclusions were obtained. (1) The δD and δ18O values of the produced water samples were between −73.37‰ and −27.56‰ (average −56.30‰) and between −11.04‰ and −5.93‰ (average −9.23‰), respectively. The water samples have D-drift characteristics, showing the dual properties of atmospheric precipitation genesis and water–rock interaction modification of the produced water. An index d was constructed to enable the quantitative characterization of the degree of D-drift of the produced water. (2) The stable isotopic compositions of produced water showed the control of the water sources on the CBM productivity. The probability of being susceptible to aquifer interference increased with the increasing span of the producing seam combination, reflected in the lowering δD and δ18O values and the decreasing gas productivity. (3) Three types of water, namely, static water, dynamic water, and mixed water, were identified. The characteristic values of the isotopic compositions of the static and dynamic water were determined. Accordingly, a quantitative identification method for the produced water sources was constructed, based on their stable isotopic compositions. The identification results have a clear correlation with the gas production, and the output of the static water contributes to the efficient CBM production. The method for the quantitative identification of the water sources proposed in this study, can help to improve the CBM development efficiency and optimize the drainage technology.

Velocity String Drainage Technology for Horizontal Gas Wells in Changbei

The Changbei gas field is dominated by wells with large horizontal displacement, which have exhibited high gas production performance at an early stage of development. With the decrease in reservoir pressure, the liquid loading in the gas well is relatively high and gas production rapidly decreases. Therefore, suitable drainage measures are required to maintain stable gas production. Based on the characteristics of the unconnected oil jacket of gas wells in Changbei, a velocity string was used for drainage. A critical liquid-carrying model was established to determine the location of liquid loading in horizontal gas wells in Changbei. First, the coefficients of the liquid-carrying model were determined through theoretical analysis of the characteristics of the gas well formation. Then, the depth setting of the velocity string was analyzed. The critical liquid-carrying model was employed to calculate the liquid-carrying flow rate of each section; the calculated flow rates were compared with the actual flow rates to determine whether fluid accumulation occurred in each section of the gas well. Thereafter, with the help of the oil and casing position, the suitable setting position of the velocity string was determined. The formation fluid was driven from the tubing into the casing owing to the increase in the overflow area, based on the principle of reducer fluid mechanics. The fluid velocity in the larger overflow cross-section decreased, thereby reducing the drainage capacity of the gas well and resulting in liquid loading. Finally, a timing analysis was performed. After the formation pressure decreased, the well production and flow rate changes were analyzed by placing two velocity strings of different sizes at different wellhead pressures in the gas well with fluid accumulation. The results indicated that although the velocity string was set at a position suitable for fluid drainage, fluid accumulation still occurred after a production period, thus necessitating replacement deliquification.

Evaluation of injectable platelet-rich fibrin produced by a simple twice-centrifugation method combined with vacuum sealing drainage technology in the treatment of chronic refractory wounds.

Objective: To evaluate the effects of injectable platelet-rich fibrin (i-PRF) produced by a simple twice-centrifugation method combined with vacuum sealing drainage on wound inflammation and scar formation in chronic refractory wounds (CRW). Methods: A total of sixty-eight patients with CRW who were admitted to our hospital were enrolled in this study. They were then randomly divided into the study group (n = 34) with being treated using negative pressure sealing and drainage technology, and the control group (n = 34) with being treated using injectable platelet-rich fibrin in conjunction with negative pressure sealing and drainage technology. The following were the primary outcomes: scar conditions at 1 and 3months after the wound was fully healed, wound healing time, hospitalization time, wound healing rate, incidence of adverse reactions, serum inflammatory indices, and pain levels were assessed 1day before treatment and 14days after treatment. The secondary outcomes were determined by comparing the proportion of positive bacterial cultures in the two groups on the day before therapy, as well as on the seventh and fourteenth days after treatment. Results: The wound healing time and hospital stay in the study group were significantly lower than that in the control group (all p < 0.001). The wound healing rate of the study group was significantly higher than that of the control group on the 14thday and 28thday after treatment (all p < 0.001). On the 14thday after treatment, the levels of WBC, CRP, and IL-6 in the study group were lower than those in the control group (all p < 0.001). The positive rate of bacterial culture in the study group was significantly lower than that in the control group on the 7th and 14thday after treatment (all p < 0.05). At 1month and 3months after treatment, the VSS score in the study group was lower than that in the control group (all p < 0.001). The total defect rate of the study group was also significantly lower than that of the control group (5.88% vs. 29.41%, p = 0.011). Conclusion: The i-PRF produced by simple twice-centrifugation method combined with VSD could reduce wound inflammation and improve scar formation in patients with CRW.

Analysis of the Application of Energy-saving Water Supply and Drainage Technology in Municipal Water Supply and Drainage Engineering Design

Analysis of the Application of Energy-saving Water Supply and Drainage Technology in Municipal Water Supply and Drainage Engineering Design

Mining Stress Distribution and Gas Drainage Application of Coal Seam Group under Fault Influence

The existence of fault structures often seriously endangers the safe production of coal mines. In order to ensure the safe and efficient production of close coal seam group mines under the influence of faults, it is of wide engineering significance to study the gas occurrence and extraction technology between coal seam groups under the influence of faults. In this study, the mining and gas drainage of 13817 working face in Yueliangtian Mine were taken as the research background. Combined with theoretical research, laboratory analysis, and numerical simulation analysis, the pressure relief range of coal seam and the evolution characteristics of surrounding rock stress were studied, the coal and gas comining system under the influence of faults was determined, the gas drainage technology was optimized, and the effect was investigated and analyzed. The results show that the gas pressure reduction zone is formed in the range of 20 m and 6 m of the lower wall of F1 fault, and the pressure relief effect is good in the range of 40 m above the roof of the working face to 20 m below the bottom plate during the advancing process. The optimized gas drainage technology has a good effect on gas control in coal seam group mining under the influence of faults. The absolute gas emission of the working face is reduced to 28~36 m3/min, the gas concentration in the upper corner of the mining face is about 0.6%, and the gas concentration of the return airflow is reduced to less than 0.5%. The gas extraction rate of No. 8 coal seam is 52.9%, and the gas content in the fault zone is reduced by 60%, realizing the safe and efficient comining of coal and gas. The research results have certain reference and application value for mine gas control with similar mining conditions.

Foam stability: The key to inhibiting slug generation in gas–liquid flow

Surfactant-based foam drainage technology is a favored method of liquid accumulation removal, and it has been demonstrated as an efficient way to improve gas production efficiency. However, foam properties are extremely complex and the same surfactant can produce foam systems with widely varying properties under different environmental conditions. This has a huge impact on the multiphase flow containing foam and thus on the efficiency of fluid removal. To further explore the influences of changing foam properties on the flow characteristics and the liquid-carrying capacity of foam, this study experimentally investigated the gas–liquid multiphase flow containing different foams in a hilly terrain pipeline with different properties in pipelines by adding SDS surfactant and MgCl2. The results show that the foam stability can significantly affect the gas–liquid multiphase flow characteristics. Adding MgCl2 enhances the stability of SDS foam. This narrows the range of intermittent flow conditions and leads to a significant fall in the critical gas velocity corresponding to the transition from intermittent to separated flow. Meanwhile, under the same gas and liquid velocities conditions, the foam with higher stability has a more pronounced suppression effect on the velocity of liquid in the upward inclined section, both the slug velocity and the liquid reflux velocity. The reduction in the holding rate also indicates that a more-stable foam improves the liquid-carrying capacity of gas and the discharge efficiency. In addition, as the gas velocity increases, the enhanced stability promotes the transition of the flow pattern from stratified to annular flow, resulting in a remarkable increase in the pressure drop gradient. This suggests that a more stable foam system is suitable for environments with lower gas velocities.

Interfacial resistance model for electro-osmotic system

Electro-osmotic drainage technology is especially suitable for low-permeability clay soil. The electrode–clay interface is believed to play a crucial role in electro-osmosis. Previous documents have highlighted the importance of the electrochemical processes at the electrode–clay interface, but few studies exist with respect to the influencing mechanisms. Therefore, the influencing mechanisms of the electrochemical processes on the electrode–clay interface have been thoroughly studied herein, both theoretically and experimentally. An interfacial resistance model in the electro-osmotic system is proposed based on the interfacial kinetic reactions of metal electrodes and graphite electrodes according to electrochemical theory. The reliability of the proposed model is demonstrated by chamber tests. The proposed model states that the most critical factor influencing interfacial resistance is the current density on the electrode surface. Other crucial influencing factors for interfacial resistance include the electrode material, surface status, pH of the pore solution, soil void ratio, conductive properties and adsorption properties.

Development history and prospect of Fel Ursi

Fel Ursi(bear bile) has been used as medicine for a long history, with wide clinical applications and definite curative efficacy. Fel Ursi has good pharmacodynamic activities in the treatment of liver and gallbladder diseases, and cardiovascular and cerebrovascular diseases. According to the places of origin, traditional Fel Ursi is divided into &quot;Dongdan&quot; and &quot;Nandan&quot;. According to the gallbladder properties, it is divided into &quot;Jindan&quot; &quot;Tiedan&quot; &quot;Caihuadan&quot;, and &quot;Youdan&quot;. With the development of bear bile drainage technology, Pulvis Fellis Ursi has entered the market and been used clinically instead of Fel Ursi. At present, obtaining artificial Pulvis Fellis Ursi by chemical compounding and biotransformation is the hotspot in medical research, which can solve the shortage problem of bear bile resources, and also protect endangered animals. The quality problem of Fel Ursi in the market is prominent, with counterfeit products prepared from sheep bile, cow bile, pig bile, and chicken bile. Due to the scarcity of bear bile resources, the related research contents are scattered, and there is a lack of systematic analysis and summary. This paper focused on the development of Fel Ursi to clarify the source and classification of traditional Fel Ursi, and summarized the harvesting, processing, identification, and use of Fel Ursi. Additionally, the paper also compared the quality standards of Fel Ursi, summarized the technological development process of Pulvis Fellis Ursi, and prospected the modern research and clinical application of Pulvis Fellis Ursi, which is expected to provided references for the collation of bear bile resources, the clinical application of Fel Ursi, the development of Fel Ursi drugs, and related research on artificial Pulvis Fellis Ursi.

Experimental investigation of mechanical properties, impact tendency, and brittleness characteristics of coal mass under different gas adsorption pressures

Understanding the mechanical properties of coal after gas and coal interaction can better guide the mining technology of gas-bearing coal seams and drainage technology of coalbed methane. In this study, triaxial compression tests of coal mass under different gas adsorption pressures are carried out to evaluate the mechanical properties, impact tendency, and brittleness of coal with different gas adsorption pressures. Results show that due to the adsorption of gas, the mechanical parameters, such as elastic modulus and strength of coal are significantly decreased. In addition to the effect of fluid pressure, the decrease of elastic energy absorbed by coal, the increase of ductile deformation and the change of molecular structure of coal particles caused by gas adsorption also significantly affect the mechanical properties of coal. The influence of gas adsorption pressure on energy input becomes gradually evident when the coal enters the stage of plastic deformation and yield failure. Then the deformation and stress bearing capacity of coal are affected, and the energy accumulation and dissipation process of coal are further affected. The gas adsorption pressure generally develops the energy absorption density and elastic energy density of three characteristic points (initial damage point, volume expansion point and peak stress point), but reduces the dissipation energy density of these points. Gas adsorption reduces the storage of deformation energy of coal, strengthens the energy dissipation, and develops the plastic failure characteristics of coal. It is not prone to appear sudden brittle failure in coal mass. Although high pressure reduces the risk of rock burst, it increases the risk of gas outburst. The chemical effects of pore/fracture fluid caused by the combined action of adsorbed and free gas lead to the further decline in coal brittleness, thus changing the deformation and failure mode of coal.

Green coal mining and water clean utilization under Neogene aquifer in Zhaojiazhai coalmine of central China

Coal plays an important role in the high-quality development of national economy and society, and overburden movement caused by coal mining has also caused groundwater loss and eco-environment damage. Under the national strategic goal of emission peak and carbon neutral, green mining and low-carbon clean production have become the mainstream production mode of coal enterprises. In this study, the overlying unconsolidated layer is divided into four aquifer groups in Zhaojiazhai coalmine of central China based on its characteristics and water yield coefficient of pumping experiment. According to the coal seam thickness, the damage range of the aquifer under the mining influence and the maximum hydrostatic reserves are accurately determined, and a combined up-down well drainage technology is proposed, which solves the water hazard threat of the safe mining under Neogene aquifer. Considering that the loss of groundwater resources will aggravate the surface subsidence , the distribution characteristics and formation mechanism of surface cracks under fully mechanized top coal caving mining are analyzed, the angular parameters of surface dynamic movement and deformation are obtained, the damage degree of mining subsidence area is divided into regions, and land reclamation measures are implemented. Combined with the clean production concept of waste heat utilization , and based on the life cycle theory, the life cycle cost model of mine heat supply mode is established. It is analyzed that the waste heat utilization of mine water and air compressor is the best way of heat supply in Zhaojiazhai coalmine, and has been successfully applied. The engineering application shows that the dewatering and drainage not only liberates the coal resource under water of 5.99 Mt, but also provides rich waste heat of mine water for coalmine clean production. The waste heat utilization saves 7000 tons of standard coal for the mine every year, which has the characteristics of low operation cost, high efficiency, energy conservation and green environmental protection. Meanwhile, using the surface movement parameter to guide the land reclamation in the subsidence area not only improves the land productivity, but also effectively improves the eco-environment of the mining area, speeds up the construction process of green mines, and provides a reference for the green mining and low-carbon production of coal enterprises. • The drainage technology is proposed to convert Neogene water into clean energy. • The waste heat utilization of coalmine is compared, analyzed and determined. • A new mode of green mine construction is proposed and implemented. • The findings are considered instrumental for green mine and low-carbon development.