According to the situation that damaged natural eco-environment in closed coal mine areas has been impeding ecological civilization construction in China, it is urgent to develop ecological restoration plan to guide concrete actions at the national level. This paper reviews the main features of ecological restoration planning for closed coal mine areas, including scales of implementation, planning aims, and methods. Then achievements made in former studies of ecological restoration planning in closed coal mines are concluded. At last, four prospects of ecological restoration planning in closed coal mines at the national level are proposed, i.e., ecological restoration planning methodology, interdisciplinary integration and talent training, application of advanced technology, and establishment of long-term ecological monitoring and census.

There are currently a large number of closed/abandoned mines in China, among which closed/abandoned mine underground space resources are the most stable and easy to develop resources, with low development costs, high returns, and easy realization. However, no one has yet conducted a comprehensive study on the underground storage space of closed/abandoned mines. Based on summarizing the research status of different types of storage (oil, gas, water, nuclear waste, seeds, etc.), this paper conducts an in-depth research on mine selection, sealing performance, storage space size, storage time and other aspects. Corresponding evaluation indicators and transformation technologies for underground space storage are proposed to formulate a theory and technology for ensuring the stability of underground space storage environment in closed/abandoned mines suitable for China's national conditions and natural geological conditions.

It is significant to construct underground reservoir to utilize underground space and water resource and energy in goaf, and to promote environmental ecological protection of mining area. Based on typical worldwide cases, this paper discusses three utilization modes of underground space and water resources based on underground reservoir:underground storage and filtration reservoir, pumped storage power station, and development and utilization of mine geothermal energy. Compared with the previous UWR with the tunnel as the main space, the storage capacity is larger and the gangue in the caving zone can be purify the mine water. This makes the capacity of underground reservoir of mine increase greatly. On this basis, the paper summarizes two key scientific problems of underground coal reservoir in China:capacity of underground reservoir and stability control of underground reservoir in mine. Furthermore, the influencing factors of reservoir capacity and stability control of the dam body and the main research methods at the present stage are given, and the follow-up research direction of construction of underground reservoir in the production and resource exhausted mines is proposed.

Combined with the key knowledge of urban gas transmission and distribution, and based on an in-depth analysis of current situation and characteristics of abandoned coal mine resources and utilization in China, this paper studies the restrictions of the permanent underground space of abandoned coal mine as urban natural gas storage space, and puts forward an idea of natural gas storage in abandoned coal mine. Sealing is the limiting condition of natural gas storage in abandoned coal mines. According to the determination of urban peak shaving gas volume, using the permanent underground space of abandoned coal mine, and cooperating with the underground space transformation and surface engineering construction, the abandoned coal mine well can be used as the underground gas storage, so as to effectively solve the imbalance between natural gas supply and demand in different periods of the city.

To improve the capacity of photovoltaic energy consumption, a hybrid power generation system of abandoned mine pumped storage and battery is constructed. Aiming at the hybrid power generation system, mathematical models of PV, abandoned mine pumped storage power station and battery are studied respectively. By introducing the cost of light discarding, an optimal scheduling model is proposed, which aims at the lowest total operating cost and the maximum PV energy consumption of the hybrid power generation system. Combined with power balance constraints, operation constraints of abandoned mine pumped storage power station and battery energy storage, an optimal solution of the scheduling model is obtained by means of CPLEX optimization tool. The results show that the scheduling strategy can achieve the optimal operation cost of the system and reduce the waste light effect.

In order to make better use of the large amount of resources and underground space left by abandoned coal mines and promote the transformation & development of energy-exhausted cities, a new technology for abandoned coal mine pumped storage power station is introduced. The overall reconstruction plan of power station construction is preliminarily analyzed. The necessity, feasibility and strategic significance of the construction of power station are pointed out. Combined with the existing construction machinery and equipment, the composition and application of power station infrastructure equipment group are discussed in terms of excavation and expansion support, earthwork, auxiliary machinery and intelligent robot. Then, in view of construction, operation and maintenance of the power station, the technical problems are summarized, such as stable support and sealing of water transmission system, throttling and drainage between multiple tunnels, anti-seepage and reinforcement of underground powerhouse, pumping and draining of natural groundwater around powerhouse, and efficient and safe transportation of personnel and large equipment. Finally, corresponding solutions are proposed for construction of underground pumped storage power station and special equipment.

Underground pumped storage station (UPSS) using abandoned mine is a newly emerging technology, which has great significance to adjust the energy industrial structure of China in the future. Pump-turbine is the key equipment of UPSS. The characteristics of large drop, small space and poor water quality of UPSS requires the pump-turbine to be of ultra-high head, small volume and high corrosion resistance. Through the analysis of domestic and foreign research status, it is found that the research on pump-turbine in UPSS using abandoned mine is not comprehensive, the study on the corrosion mechanism of pumpturbine with mine water as working medium is not systematic, nor the transition process of pump-turbine frequently switching working conditions for new energy consumption is clear. Therefore, it is suggested to further develop a hydraulic model design optimization technology, research safe and stable operation technology in the transition process in frequent switching conditions, and study the coupling mechanism of corrosion-sediment wear-cavitation erosion and collaborative control technology.

Based on the literature of foreign industrial heritage tourism included in the Web of Science, 499 related articles are reviewed, and the research trend, research focus and research methods are summarized for the abandoned mining area industrial heritage tourism., We argue that overseas research on industrial heritage tourism is application-oriented with increasing research interest, and that so far the amount of research is limited but the potential for future research growth is huge. China's future research should focus on improving theory of industrial heritage tourism system, strengthening the research on tourists spending behaviors and in-depth research of community management, promoting the establishment of development potential evaluation framework, and so on.

Based on an analysis of the policy background and development status of transformation and upgrading of resourcebased cities, a structural equation model is used to construct an index system of transformation influencing factors for resourcebased cities, which has five dimensions, i. e., economy, policy, society, innovation, and environment. Huainan City of Anhui province is taken as an example to carry out an empirical analysis. The analysis shows that innovation factor, environmental factor and social factor can directly affect the transformation effect of resource-based cities. At present, under the background of policy pressure, environmental factors have the most obvious impact on the transformation effect, and the standardized path coefficient β reaches 0.701. Further more, policy factor and financial factor can indirectly affect the transformation effect of resource-based cities through innovation, environmental and social factors. Therefore, combined with the actual development of a large number of abandoned mines in Huainan City in recent years, corresponding transformation and upgrading path suggestions are put forward.