The Habitat And Vegetation Constructing For Spontaneous Combustion Gangue Pile In Yangquan, Shanxi Province

The study depend on environmental ecology as the theoretical foundation, the basic engineering technology of gangue piles about Habitat-building was advanced, which was found from the study of spontaneous combustion,water content and physical and chemical characteristics of gangue piles; the basic theory and techniques about vegetation redvelopment of gangue piles were advanced on the basis of characteristics of the resistance under the gangue envieonmental stress. With the reclamation project of Yangquan Coal Industry (Group) Company Ltd., 280 spontaneous combustion, the simple fire technology on industry and simple cultivation techniques on eco-forestry were integrated, and the theoretical and practical breakthrough was achieved in the construction of habitats and vegetation of gangue piles.The main findings are as follows:1.Fundamental characteristics of spontaneous combustion gangue piles1) Survey found that: (1) the "chimney effect" can be strengthened and the fire increased if covered improperly; (2) the traditional design and construction of retaining walls and soil cannot be separated by air; (3) various facilities built on gangue piles during the management of the coal waste dump form a new channel air flow; (4) explosion can be triggered when water is imported to high-temperature egions and grouting fire.2) Divener2000 was first used on monitoring water-dynamic of gangue piles. Soil and water conditions of the gangue piles were changed by soil cover. (1) The soil moisture content was reduced after the soil was covered, as in the coal mine in Yangquan for example, where the annual average water content dropped from 22.4% to 12.2% after soil cover; 2) the rule of gangue piles seasonal water changes was changed by soil. Take the coal mine in Yangquan as an example, the bare did not change significantly, but the gangue files covered by soil which water content changes was similar to the dynamic changes of seasonal precipitation. The time of minimum water was before the onset of the rainy season in May; the most arid layer was in high temperature gangue layer, of which the lowest water content was only 2.1 percent. (3) it was found that there was little variation at the vertical bare gangue and that the upper 0-20cm of water was relatively active, but with lower stability. The vertical change was very obvious after the gangue was covered by soil.3) The spontaneous combustion gangue piles'temperature characteristics are: (1) the level of high-temperature distribution points and the temperature points were unregulated and the distribution was uneven, with some fire zones overlapping; (2) the temperature in the mountain fell from high to low; (3) internal temperature of gangue piles first rising then decreasing from outside to inside, and about 7 m was the highest around; (4)the soil's thermal conductivity of the spontaneous combustion gangue profiles was lower, where the temperature from maximum points dropped sharply with the increase in distance; (5) the changes of the shallow layer temperature was similar to air temperature, which receive daily changes and seasonal changes, but the deep layer temperature did not change significantly.4) Salt and acid were the products of the spontaneous combustion gangue profiles, with the total salt content being as high as 3.80 percent, but there were no rules in the salt content of the vertical and horizontal distribution. The pH in high-temperature regions was lower, with pH minimum at 2.8, the pH in the region without spontaneous combustion was close to normal pH, and pH maximum was 7.9.2. Constrains of vegetation construction of spontaneous combustion gangue piles1) Many factors affect the vegetation of spontaneous combustion gangue piles; high temperature, drought, salt injury, acid, compaction and the lack of nutrients are the most important factors.2) Heat stress is the main factor affecting the survival of plants during vegetation construction of spontaneous combustion gangue piles, but the plants are adaptable. The studies of plant under heat stress show that: (1)"Death"temperatures vary greatly among plants ranging from 30℃to 70℃. The plants are "dead" within the 28-360h stress time; (2) They have strong self-healing ability and the ability to avoid heat stress, the "dead" plants can "resurrect" after the lifting of the heat stress. The permanent "death" temperature for each plant has not been established.3) Photosynthesis rate, transpiration rate, intracellular concentration of carbon dioxide, stomatal conductance of plants would be affected under salt stress. The salt content of area in 280 gangue pile where plant can grow is 0.13%.3. Habitat construction of spontaneous combustion gangue piles1) To establish strengthened "chimney effect" after the gangue was covered by soil, new retaining walls and drainage facilities construction method were designed, as an effective solution to prevent the air entering from the foot and draining from the top.2) Regarding the problem of grouting fire, a patented technology called "grouting apart-oxygen-tube for spontaneous combustion gangue piles" (Patent No.: ZL 2006 2 0024643.0) was developed tosolve the problem of explosion induced by water and gas.3)The contradictions between quenching fire and plant growth were solved by the method of compound soil covering.4)The slope runoff water catchment systems were proposed from the perspective of using rainwater resources.5) Soil improvement study found that: (1) Acid in spontaneous combustion gangue piles could be counteracted by loess. (2) Loess could not solve the problem of salinization; there was still great salt in the gangue covered by loess.6) Gangue microbes can ease the stress on plant growth. Ectomycorrhizal fungi (Gomphidium viscidus) can survive in the high concentration of coal gangue extracts. For example, the survival and growth of Pinus bungeana in weathered coal gobs were significantly increased after Gomphidium viscidus were vaccinated in Pinus bungeana.4. Vegetation construction of spontaneous combustion gangue piles1) Study found that: plant screening principles in spontaneous combustion gangue piles were: (1)suitable plants planted in suitble places; (2) Native plants are main. 2) According to the demands of high temperature-resistant, drought-resistant, salt-resistant, the arbors are Elm, Acacia, Ailanthus altissima, Arborvitae, Pinus bungeana, the shrubs Amorpha fruticosa, Caragana, mountain acacia, north Celastraceae, purple Yexiao Berberis, Forsythia, thevine plants Parthenocissus, Periploca, mountain buckwheat, and the herbs purslane, a ghost-grass, A. adsurgens, alfalfa, Ap Mao, tall fescue, Cimicifuga Tangdeng.3) Cultivation methods of spontaneous combustion gangue piles were: early herbaceous plants and pre-rapid growth of shrubs mainly and later replanting container seedlings of woody plants.4) The recommended structure for the community are: herbaceous plants including legume and gramineous grass to lower mainly, woody plants in the upper-layer mainly.5) The management and protection method is: develop woody plants into shrubs, community construction, community structure is composed mainly of cover plants controled by artifical.