Impact Of Mining On The Grassland Landscape And Heavy Metals In Soil

Based on RS and GIS technology,this paper classified the three phase TM remote sensing images of Xilinhaote in 1995,2005 and 2015,and analyzed the types,quantity and area of mineral exploitation and the change of landscape pattern in the last 20 years.The landscape patterns in the 10 km buffer zone of typical opencast coal mines,fluorite and tin polymetallic minerals were analyzed by using high resolution remote sensing images.In the same time,the spatial distribution characteristics and the sources of soil heavy metals(Zn,Cr,Cu,Ni,Mn and Co)in the 5km buffer zone were analyzed It provides basis for rational mining of mineral resources and effective management of ecological environment.The main results are as follows:1.In the past 20 years,the type,quantity and area of mining area in Xilinhot increased significantly,with an increase of 71.43%,220% and 154.2% respectively.The area of construction land,traffic land and saline alkali area increased significantly around the mining area.The water area decreased significantly,and the heterogeneity of grassland landscape increased and fragmentation increased.2.During the period of 2009~2015,the grassland area in the 10 km buffer zone of typical open pit,fluorite and tin polymetallic ore decreased significantly,the number of landscape patches,landscape diversity,and fragmentation of the landscape increased obviously.Mining has caused great damage to the grassland landscape in mining area.The area of grassland in the mining area of open pit is reduced by 10.6%.The area of mine pit,construction land,industrial and mining storage,dumping ground,washing pool and traffic landscape increased respectively,the increase was 729%,178.1%,143.39%,94.88%,73.6%,0.45%,and the grassland and water area of the fluorite mine area were reduced by 1.13% and 4.76% respectively,and the washing pool,dump,pit,construction land,transportation land and work were also increased.The ore storage has been increased by 269.39%,85.79%,84.71%,44.82%,33.33% and 28.03%.The grassland in the tin polymetallic mine has been reduced by 4.7%.The area of construction land,ore washing pool,industrial and mining storage,dumping ground and transportation land has been increased by 191.77%,100%,68.3%,25.37%,7.29%,in three mining areas,the number of patches of industrial and mining storage,transportation increased and fragmentation increased.3.From the perspective of land occupation,the coal mines in 2009 and 2015 have the largest area,and the land occupations for the four types of landscapes including pits,dumps,washing tanks,and industrial and mining storage are ranked first.The second of the area is fluorite and tin polymetallic mine has the smallest area.From the number of plaques,the number of patches in coal mines was the largest in both 2009 and 2015,and the damage to grassland was the most serious.In 2009,second of the damage to grassland was fluorite.By 2015,the damage of tin polymetallic ore to grassland was more than that of fluorite.The number of patches in waste dumps,industrial and mineral storage,wash basins and bare landscapes is coal mine> fluorite ore> tin polymetallic ore;overall,the coal mines in the three types of mines have the largest diversity and the strongest heterogeneity,the lowest degree,the largest degree of fragmentation,the greatest impact on grassland continuity.4.From the perspective of heavy metal content,the heavy metals Zn,Cr and Cu in coal mines all showed a trend of decreasing with the increase of the distance from the center of the mine.The content of Zn,Cr,Cu,Ni,Mn,and Co in the soil of fluorite ore deposits showed the highest in the central area of the mining area,and decreases with the increasing distance,and the trend of the upwind direction and the side wind upward are both increasing firstly and then decreasing.The sources of Zn,Cr,and Cu in six soil heavy metals can be classified into one category,Ni,Mn,and Co are other types in the coal mine buffer zone;among the six elements in the open-pit fluorite mine buffer zone,Mn is The source is one,and the other elements are from another source.