Remote Sensing Monitoring And Ecological Restoration Evaluation Of Mines In The Qilian Mountains,Gansu Province

As a special geographical area,in the process of developing mineral resources,mines not only contribute to the economic construction,but also cause serious damage to the ecological environment of the mining area,leading to increasingly prominent geological problems and environmental pollution of mines.The Qilian Mountains is rich in mineral resources.It is not only an important ecological barrier in Western China,but also an important source of water and flow in the Yellow River Basin,and also a priority area for biodiversity protection in China.This paper takes the Qilian Mountains in Gansu province as the research area,based on GF-1/2 and ZY-3 remote sensing images to carry out remote sensing monitoring of mines in the Qilian mountains area,and analyzes the development and utilization of mines,environmental pollution and geological disasters in this area from 2014 to 2018.At the same time,based on the Landsat OLI remote sensing image,the vegetation coverage of the mines in this area from 2014 to 2018 is estimated,and the current situation and changes of the ecological restoration and management of the mines are evaluated.At the same time,countermeasures and suggestions are put forward for mine ecological restoration.The results show that:In 2018,there were 2180(48 ground fissures)mining spots(damaged land,environmental pollution,geological disasters and hidden dangers)in the Qilian Mountains of Gansu province,covering an area of 112.99 km~2(6.45 km long ground fissures).Among them,there are 2101 damaged lands in the mine development,covering an area of 76.61 km~2,accounting for 96.38%and 67.80%of the corresponding total.In 2018,the number and area of mining spots in the Qilian Mountains of Gansu province showed a decreasing trend from east to west,among which the number and area of mining spots in the east section were the largest(1546and 49.96 km~2),followed by the middle section(409 and 21.89 km~2)and the west section(146 and 7.75 km~2).The development and utilization of mineral resources in the Qilian Mountains of Gansu province are mainly energy,metal and non-metal minerals,with the largest number and area of non-metal mineral spots,followed by metal minerals and the least energy minerals.In 2018,there were 2101 mining spots in the Qilian Mountains of Gansu province,with a damaged land area of 76.61 km~2.Among them,the number and area of mine sites are the largest,the number of mine waste material sites and transfer sites are the same,and the number of mine buildings is the least.In 2014,there were1402 mining spots in this region,with a damaged land area of 82.65 km~2.From 2014to 2018,the number of mining spots in the Qilian Mountains of Gansu province increased by 703,with an area of 36.84 km~2,accounting for 92.64%of the total area in 2014.The number and area change trend of mining spots from 2014 to 2018 is consistent in the Qilian Mountains of Gansu province.In addition to the transfer sites,the number and area of mine sites,waste material sites and mine buildings are increasing,with the most increase in mine sites and the least in mine buildings.From 2014 to 2018,the number and area of subsidence area and dust pollution are decreasing,the number of debris flow is unchanged,the area is increasing,and the number and area of other disasters are increasing in this region,among which the number of ground fissures is the largest,debris flow and dust pollution is only one,located in Sunan Yugur Autonomous County.From 2014 to 2018,there are many kinds of disasters and hidden dangers caused by mining in Tianzhu Tibetan Autonomous County and Honggu District,and Jingtai county is the least.The spatial distribution pattern of vegetation coverage and its corresponding grades in the Qilian Mountains of Gansu province from 2014 to 2018 has certain similarity,showing the characteristics of high in the middle east and low in the west.The vegetation coverage of the area and its mines improved from 2014 to 2018,and significantly improved from 2016 to 2017.Among them,the vegetation coverage in most of the central and western regions of the study area increased slightly;the vegetation coverage in most of the central and eastern regions did not change,and the vegetation coverage in some regions degraded;the vegetation coverage in some regions of the experimental area of the Qilian Mountain National Nature Reserve in Gansu province decreased.The area with the largest increase and degradation of vegetation coverage in the mining spots,and the area of mine building increase and degradation is the smallest.In 2018,the Qilian Mountains of Gansu province recovered 234 mining spots with an area of 6.16 km~2.Among all counties(regions),Sunan Yugur Autonomous County has the largest number of mining spots for restoration,and Tianzhu Tibetan Autonomous County has the largest area.This region recovered 8 mining spots with an area of 1.86 km~2 in 2014.From 2014 to 2018,the number of restoration spots in the Qilian Mountains of Gansu province increased by 226 and the area increased by4.29 km~2;From 2014 to 2015,the number and area of restoration did not change,and since 2016,the number and area of restoration showed an increasing trend,while in2017,they increased rapidly.Different counties(regions)have different time for mine restoration.Honggu District,Subei Mongolian Autonomous County and Tianzhu Tibetan Autonomous County started earlier,the mine has been restoration in 2014,and other counties and regions began to treat the mine in 2016.