Abstract:

Mining of shallow coal seams mining may cause formation of lots of fissures, some of which close automatically, while the others hardly close and then develop into permanent fissures. In ecological reconstruction, ground fissures and their surrounding vegetation covers is somewhat related to the effect of ecological reconstruction of the mining area. The working faces opened up in 2003, 2004 and 2005 in the Daliuta mining area were selected as examples for field investigation and statistical analysis of fissures. Firstly, based on the layouts of underground mining, distribution of permanent fissures was analyzed; basic information of permanent fissures and their surrounding vegetation covers was extracted with the aid of the ArcGIS 10.0 software; and then statistic analysis was performed of variation of the vegetation covers around the fissures. It was found that fissures were mainly distributed at open-off cuts, stopping lines, bordering of two working faces and intersection of tunnels, and the number of fissures rose with rising undulation degree of the terrain. Statistic regression analysis of 192 ground fissures shows that the vegetation 2 m away from permanent fissures is significantly and closely related to the fissures (P<0.05), while the vegetation >2 m away from fissures is not so much related (P>0.05), which indicates that the vegetation along the fissures is highly affected by other factors. Analysis of seven randomly selected permanent fissures shows that the fissures have some impact on the vegetation within 4 m alongside them.

Key words: coal mining, permanent fissure, destruction of vegetation