Sorting out the mode of mine ecological restoration and activation utilization

1. Main problems in mine rehabilitation and activated utilization

The restoration and activation of mines in China are mainly faced with such problems as capital investment, land use policy and withdrawal mechanism.

1.1 Mining activities have a great impact on the natural environment and require large investment in ecological restoration funds and technologies

The restoration and comprehensive treatment of mine geological environment are the basis of mine activation and utilization. The extensive development mode still has a serious impact on the geological environment of the mine. The land use and development behaviors of mining sites, tailings, storage yards, waste dumps, goaf, workshops, mines and mining facilities have damaged the original vegetation and topography, resulting in enhanced heterogeneity of the mining landscape, destruction of stability, and impact on ecological processes. Lead to a certain range of surface collapse and groundwater level changes, often lead to surface movement basin, ground cracks, collapse pits, seasonal water, accelerate farmland soil salinization, resulting in higher ecological restoration technical requirements and environmental governance and restoration costs.

1.2 Insufficient connection between the mining cycle and the land transfer time limit of mining land leads to idle land after mine closure

According to the provisions of the Land Administration Law, the Rules for the Implementation of the Mineral Resources Law and other laws and regulations, the term of use of construction land shall be clearly stipulated by the State. The maximum term for the transfer of mining land is 50 years. However, the use mode and term of mining land are determined by the characteristics of mineral resources themselves. Generally, the use cycle of mining land for mineral resources suitable for open-pit mining may only be 4 to 6 years, and some may even be shorter. The mining land that needs to be mined underground may be used for far more than 50 years due to the distribution conditions of underground mineral resources. After a production cycle of just a few years, open-pit mines often become idle land.

1.3 The withdrawal mechanism of mining land is not perfect, and the activated utilization lacks policy support

Due to the imperfect withdrawal mechanism of mining land, after mining enterprises complete reclamation of mines, the land is difficult to replace or return to the government, and it cannot be further activated. Due to various reasons, the policy [1] that "state-owned industrial and mining enterprises can replace the rural collective cultivated land destroyed due to production by reclaiming the original state-owned abandoned land with the same quantity and quality of farmland has not been effectively implemented [2]." On the other hand, at present, there is no perfect policy support for the transformation of mining land use, which makes it difficult to effectively promote the restoration and activation of mining land.

2. Model reference for mine restoration and activation utilization

In the world, mining ecological restoration has been explored and practiced for a long time, and basically formed a technical system mainly based on matrix improvement, phytoremediation, soil quality evolution and plant succession. In terms of land function transformation, apart from the traditional reclamation and forest utilization, it can be basically summarized into three activated utilization modes: ecological recreation, heritage memorial and regeneration.

2.1 Ecological recreation model

Ecological recreation mode is to build abandoned mining areas into ecologically themed country tour parks and theme parks on the basis of mine environment regulation and restoration of regional biodiversity, relying on beautiful outdoor environment and characteristic landscape, so as to reshape habitats, enrich ecological recreation products for surrounding residents, and promote regional economic development.

(1) State-owned Akashi Kaikai Park

Japan's state-run Akashi Kaikai Park was originally a massive quarry that, from the 1950s to the mid-1990s, provided 1.06 trillion cubic meters of sand for the construction of Kansai Airport and artificial islands off the coast of Osaka and Kobe, digging depths of more than 100 meters and creating a wide range of exposed mountains. Through years of continuous vegetation restoration and rainwater management, the project transformed it into a future-oriented regional leisure place including an international conference center, a star-rated hotel, a large greenhouse, an open-air theater and other facilities, which is still a popular destination for global flower tourism.

Beginning in the 1980s, Hyogo Prefecture, where the island is located, commissioned Tadao Ando to carry out planning and design, and set up a committee of greening experts to restore vegetation. The plan emphasizes the restoration of the natural state, the formation of a good landscape and the creation of a recreational space for people. The scientific method of planting makes this plan possible, including fixing a honeycomb of three-dimensional metal plates on the bedrock, filling it with new soil and covering it with grass curtains to conserve water. The irrigation system uses embedded polyethylene pipes with a density of 1 meter. At the same time, because the local precipitation is relatively low, so in order to meet the needs of plant growth, the use of surface water collection, water recycling and other technologies.