1、 Background of iron ore filling
With the exploitation of mineral resources, iron ore mining is facing many problems. During the mining process of underground iron mines, waste rocks and tailings will be generated, which will occupy a large amount of land, including farmland, if stored on the surface. For example, the accumulated storage capacity of waste rock and tailings generated by metal mines in China has reached 6 billion tons (4 billion tons for metal mines alone), and is growing at a rate of nearly 300 million tons per year. At the same time, the rate of land occupation has reached 200 hectares per year, which not only causes waste of land resources but may also affect food problems. Moreover, underground mining may cause surface displacement and collapse, damage natural landscapes and environments, and bring various disasters. For example, in China, improper handling of underground mining voids has caused surface displacement and collapse, resulting in the destruction of 2 million hectares of land and affecting nearly 40 cities, of which 25 have caused serious disasters. In this context, iron ore filling has become a trend to solve these problems. In the context of the country's emphasis on the rational development and utilization of mineral resources, land protection, and environmental protection, the application of backfill mining methods in iron mines is of great significance. Currently, backfill mining methods have been designed and adopted in Caolou Iron Mine, Lilou Iron Mine, Zhengjiapo Iron Mine, Nopu Iron Mine, and Xulou Iron Mine, and the national defense iron mine scheme design also adopts backfill mining methods.

2、 The significance of iron ore filling
Regarding resource recycling
Improve ore recovery rate: The filling mining method can use cemented filling, leaving no top, bottom, or intermediate pillars in the mining area, and the recovery rate can reach over 85%. Compared to the caving mining method (with ore loss rates of over 20%, sometimes up to nearly 30% for the pillarless segmented caving mining method) and the open pit mining method (with loss rates below 20%), backfill mining has significant advantages in improving ore recovery rates.
In terms of environmental protection
Reduce surface occupation: Waste rocks and tailings generated from underground mining are stored on the surface, occupying a large amount of land and farmland. Restoring these waste rocks and tailings and filling the underground goaf can save a large amount of land and farmland occupation. For example, in Caolou Iron Mine, filling the goaf underground can reduce the amount of tailings stored on the surface and decrease the capacity of the tailings pond.
Protecting surface stability: The use of backfill mining methods can reduce rock mass movement and surface displacement around underground voids, reduce the entry of upper rocks and sand into the mined ore during mining, thereby reducing ore impoverishment rate, and avoiding disasters such as surface collapse, protecting natural scenery.
Reduce waste emissions: Fill the tailings and other waste discharged from the beneficiation plant underground to reduce the amount of tailings stored on the surface and minimize pollution to the surrounding environment.
Mine safety aspect
Maintaining geological stability of mines: Backfilling mining is a method of filling goaf and forming a stable support system, which can effectively prevent disasters such as collapse and subsidence of goaf, ensure the stability of mines, reduce geological risks, and ensure the safety and sustainable development of mines.