Environmental Effects Of Mining And Strategies For Integration Of Mine Resources And Environment

Sustainability issues and the significant environmetal problems in mining have led to increased public concerns around the world. Many people are devoting themselves to solving them from different perspectives. Years of unregulated mining and mineral extraction activities within the mining district of Dachang, located at the upper region of Diaojiang river, have caused severe environmental problems, which reflect the historical negative environmental legacies produced by unregulated mining. On the basis of identifying the environmental impacts caused by mining activities in Diaojiang river basin, this article analyzes some technical details including the reuse of mine tailings, plant restoration and reconstruction, etc., and discusses the necessities of building an integrated system incorporating environmental protection into mining processes from a sustainable development perspective. The main research methods and works comprise the following: (1)Investigating the species, niches of plants colonising naturally at the abandoned mine sites, and analyzing heavy metal concentrations of the plants and the mine wastes; (2)Investigating the distribution and area of abandoned mine sites using GPS; (3)Investigating the flooded area using a high-tech measuring instrument n2000GPS,and analyzing the relationships between the flooded area and the polluted area along Diaojiang river; (4)Analyzing the concentrations of heavy metals in soils along Diaojiang river; (5)Collecting data by visiting all the related departments; (6)Conducting field trials of revegetation at Kengma tailings pond; (7)Conducting pot culture experiments of Leucaena leucocephala(Lamk) Dewit in a green house. The following conclusions can be drawn: (1) Severe environmental problems have been resulted due to the mining operation at the upper region of Diaojing river basin, and the pollutants extend to the lower reaches which are more than 200 kilometers away. (2) Large amounts of abandoned mine sites which include tailings, derelict mining and extraction sites, and the abandoned arable land caused by mining, are not physically stable and contain toxic elements which can serve as a more or less permanent source of threat to surroundings. The plants on the mine sites contain high levels of heavy metals which may lead to more serious detriment to local ecosystem. (3)Severe water pollution and sediment build-up at the Diaojiang river bottom have spoiled aquatic ecosystem, causing a fish kill and forcing local people to turn off their drinking water intakes, and increased the incidence and severity of overbank flooding. All of these can have a significant negative effects on the local ecosystems along the river. (4)The flooding resulted in the deposit of mine waste on the arable land, and caused severe heavy metal contamination of soils along Diaojiang river. There are obvious mine wastes in soils of upper region, so it's relatively easy to identify the polluted area, but in the lower reaches, mine wastes are not so obvious although the concentrations of pollutants in soil are still high. The plough sole of rice land can obstruct the transport of heavy metals downwards. The concentrations of Cd, Pb and Zn in rice and corn have exceeded the national food standards, and may have serious detriment to public health. (5)There are still several kinds of valuable elements worth of reextration in the mine tailings. (6) The selection of plant species and appropriate amendment of substrate are the key to successful revegetation on the mine sites. The results of field trials at Kengma tailings pond demonstrate that Saccharum arundinaceum, Arundo donax L. and Leucaena leucocephala (Lamk) Dewit. can grow well when the substrate is amended with garbage compost, especially for L. leucocephala which bore fruits after 16 months'growth, and the three plant species can be introduced as pioneer plants for vegetation establishment on the mine wastes. The results also indicate that pure tailings inhibit the growth of L. leucocephala, but not seriously affect the growth of S. arundinaceum and A. donax. The results of pot cultivation in green house indicate that different combinations of tailings and garbage compost have different effects on the growth of L. leucocephala. Adding appropriate amount of NH4H2PO4 to the substrates composed of tailings and garbage compost can be helpful to the growth of L.leucocephala. (7)Mineral development has been often hostile to well environment in the history of mining. It's essential to introduce an new framework which can combine them together. The integration of mine resources and environment is a theoretical framework which contains two basic parts: First, mine resources are the components of mine environment which have economic value, so it's inevitable for mine environment to be changed in the process of mineral development, but the environment problems are often the results of unreasonable mining operation, and the mine wastes can be seen as the unused resource. Second, only if environmental protection measures are incorporated into the whole process of mineral development, the environmental problems caused by mining could be solved soundly. The distinguishing features of this article comprise the following: (1)Analyzing the environmental impacts of mineral development in Diaojiang river basin, including the impacts on soil environment, water environment and ecological environment,etc.. (2) Conducting the field trials at Kengma tailings pond for the selection of appropriate plant species which can endure high levels of heavy metals in tailings. Conducting the pot cultivation experiments in a green house for the growth of L. leucocephala which was planted in the substrates composed of tailings and garbage compost. The results was as expected. (3) Analyzing the contaminated area by an innovative method combining sampling analysis with GPS measurement. (4) Defining an new concept "the integration of mine resources and environment", and applying it to regulate the treatment of historical environmental problems and the development of mine resources. The innovations of this article comprise the following: (1)Defining an new concept "the integration of mine resources and environment"and putting forward a series of strategies for the treatment of historical mining legacies and prevention of new environmental problems in Diaojiang river basin. (2)Revealing the remarkable effects of mineral development on water, soil and ecosystem in Diaojiang river basin. The pollution extends to the lower reaches which are more than 200 kilometers away. (3)Proving that overbank soils along Diangjiang river have been severely contaminated by heavy metals and the plough sole of rice land can obstruct the transport of heavy metals downwards.(4) S. arundinaceum, A. donax and L. leucocephala can be introduced as pioneer plants for revegetation on the mine wastes. Adding appropriate amount of NH4H2PO4 to the substrates composed of tailings and garbage compost can be helpful to the growth of L. leucocephala.