Farmland damage due to coal mining subsidence and its remediation in Eastern China

Subsidence damage on farmland due to coal mining can be classified into two types: landscape damage and soil damage. The water accumulation, land sloping and fissures are typical damage characteristics of the subsidence landscape in Eastern China. Based on the dynamic tests of soil properties in subsided land, the rules governing soil changes were defined. It is believed that changing soil properties are the main reason of lower farmland productivity. Soil physical properties are sensitive to mining subsidence, but soil chemical properties are not sensitive, except for soil electrical conductivity. Soil salinisation is the most important change resulting from mining subsidence. The soil analysis of subsided lands also indicates soil erosion problem due to subsidence, most severe in the middle of the affected area. To remedy the subsidence damage, several reclamation treatments are discussed in this paper, such as “Digging deep to fill shallow”, appropriate drainage and backfilling.