The Establishment And Application Of Opencast Coal Mine Ecological Impact Post-assessment Index System

Based on the existing research achievement of the concept, methods and procedure of environmental impact post-assessment, according to its principles and processes of the indicator system establishment, and combining with the opencast coal mine ecological impact, this paper probed and studied the establishment of ecological impact post-assessment indicator system of opencast coal mine. Then take Hei-Dai-Gou as an example, by the means of collecting information, field investigation and aboratory disposal, together with the methods of individual index assessment, Analytic Hierarchy Process (AHP), fuzzy comprehensive assessment and ecology theory, the Hei-Dai-Gou mine ecology impact was evaluated and analysed with the application of this indicator system, in order to provide reference and guidance for this type of projects. The conclusion was drawn as following.1,The indicator system of opencast coal mine in this study contained 3 first class indicators, which were vegetation, soil and landscape. Then they were divided into 10 second indicators, which were biomass of herb layer; species richness; species diversity; species evenness; soil organic matter; total nitrogen, total phosphorus and total potassium; hydrolytic nitrogen, available phosphorus and available potassium; heavy metals of soil; landscape diversity and landscape evenness index.2,The conclusions of the single indicator evaluation on Hei-Dai-Gou opencast coal mine were:1)Comparing with the original geomorphy near mining area, the species richness after restoration in mining area was lower, but the vegetation biomasswas a little higher, species diversity and evenness index were both higher, As a whole, the plant communities of mining area had a favorable developing trend.2) The reclaimed soil was alkalescent and with a inferior nutrient level, comparing with the original geomorphy soil, the content of organic matter, total nitrogen and hydrolytic nitrogen in dump soil were lower, the content of total phosphorus, total potassium, available phosphorus and available potassium in dump soil were higher; the content of heavy metals of Cd, Hg, As, Cu and Cr in dump soil were in the bound of background values, the content of Pb and Zn were beyond the background.Cd, As,Cu and Zn were higher than they were in the original geomorphy soil, while Hg, Pb and Cr were lower. However, all of the soil heavy metals didn't exceed the initial pollution value and the Soil Environmental Quality Standards.3) Comparing with the landscape before mining, the type and area of landscape in mining area have had a great change. The main type were still grass and farmland, but the area of grass was increased obviously, while the area of unavailable gully and barren land reduced evidently, land for industrial and mining use were newly increased, the area of farmland, residential points and roads were reduced, the landscape type and area of forestry land, water area and wetland vegetation were increased in different degree; the landscape diversity and evenness index were declined.3,To the comprehensive assessment of Hei-Dai-Gou opencast coal mine ecological situation, the importance order of the 3 indicators was vegetation >soil >landscape by the AHP method, the result of the fuzzy comprehensive assessment model showed that the ecological situation of Hei-Dai-Gou mine was in a "better" grade. Its ecological effect was notable.