Preliminary Evaluation On The Effect Of Ecological Restoration Demonstration Project Of Waste Dump In Yangchangwan Coal Mine In Ningdong

Aiming at the problems of imperfect technical system,lack of monitoring and evaluation of engineering effect and popularization of ecological restoration project of gangue dump in Ningdong coal base.Based on the screening and integration of local existing technologies,14 ecological restoration integrated demonstration plots with 6 technical modes,including ecological bag,ecological stick,wire gabion,gravel sand barrier,living sand barrier and wheat straw sand barrier,were designed and built in Yangchang Bay gangue dump in Ningdong.Thirteen monitoring indexes were determined from 4 aspects of vegetation restoration effect,soil improvement effect,soil and water conservation effect and construction cost of the 6 technical modes.A monitoring method combining unmanned aerial vehicle,ground investigation and positioning monitoring was adopted to carry out a growth season observation and data collection.Furthermore,the effect of six ecological restoration modes is comprehensively evaluated by using the principal component analysis method,and an ecological restoration technical mode suitable for the gangue dump of Ningdong coal base is put forward.The main research conclusions are as follows.(1)After a vegetation growing season,the surface soil hardness in each plot shows an increasing trend,but the change amount varies with the pattern.Among them,gravel sand barrier and wheat straw sand barrier have the most obvious changes in surface soil hardness,followed by living sand barrier mode,ecological bag mode,ecological bar mode,wire gabion mode and control.(2)The observation and analysis results of vegetation coverage,richness and aboveground biomass in six technical model experimental plots show that the vegetation restoration effect of wheat straw sand barrier plot is the best,with coverage of 45%,richness of 1.23 and aboveground biomass of 0.600 kg/m,followed by gravel sand barrier model,living sand barrier model,ecological bar model,ecological bag model,wire gabion model and control.(3)The runoff and sediment yield of the six technical models are gravel sand barrier model,wheat straw sand barrier model,living sand barrier model,wire gabion model,ecological bar model,ecological bag model and control.The runoff and sediment yield of gravel sand barrier model plot is the least,with the average runoff depth of 1.29mm during the observation period,which is 76.66%lower than the control,and the average sediment yield per unit area is 25.07g/m2,which is 81.86%lower than the control.(4)The construction cost of the six technical modes of residential quarters from high to low is in turn living sand barrier mode,wire gabion mode,ecological stick mode,wheat straw sand barrier mode,ecological bag mode,gravel sand barrier mode and control mode.Among them,the living sand barrier model and the iron wire gabion model are less economical,with the planting costs reaching 49.36 yuan/m~2 and 46.86 yuan/m~2 respectively.The ecological bag model,gravel sand barrier model and wheat straw sand barrier model are all more economical,with the planting costs reaching 16.7 yuan/m~2,16.57yuan/m~2 and 16.86 yuan/m~2 respectively.(5)The comprehensive score calculated by principal component analysis shows that the ecological restoration effects of the six technical modes are gravel sand barrier mode,wheat straw sand barrier mode,living sand barrier mode,iron wire gabion mode,ecological stick mode,ecological bag mode and control mode from good to bad.Therefore,the gravel sand barrier,wheat straw sand barrier and living sand barrier modes initially recommended in this paper can be widely popularized in local areas,and the wire gabion mode,ecological stick mode and ecological bag mode need further monitoring.