Based on the production data of a large number of surface drainage wells in the Huainan mining area,the present study shows that four types of typical production characteristics for relieved methane wells are recogniz...Based on the production data of a large number of surface drainage wells in the Huainan mining area,the present study shows that four types of typical production characteristics for relieved methane wells are recognized,of which the stable type for production and gas concentration is the most dominate,as determined by a comprehensive study on the volume and concentration of drained gases, as well as the stress changes of rocks influenced by mining.Some influence factors for the productive differences of the drainage wells were also been discussed.The results indicate that protective coal-seam mining has a significant effect on overlying strata,which promotes the development of pores and fractures of coal reservoirs for methane desorption and migration;however,the production and the stability of drainage wells are affected by deformation and damage of the overlying strata.The second distribution of strata stress is caused by mining engineering,and if the stress load is larger than the carrying capacity of the extraction well,the gas production would be influenced by the drainage well that has been damaged by rock movement.Furthermore,the case damage occurs first in the weak, lithologic interface by its special mechanical properties.The stability of drainage wells and the production status are also influenced by the different drilling techniques,uneven distribution of gas concentration,and combination of gob gas and methane from the protected layer.展开更多
The purpose of this work is to study the effect of a type of water-saving irrigation （WSI） on nutrient runoff of paddy field. The volume of surface drainage was maintained low by WSI. In particular, WSI effectively ...The purpose of this work is to study the effect of a type of water-saving irrigation （WSI） on nutrient runoff of paddy field. The volume of surface drainage was maintained low by WSI. In particular, WSI effectively reduced surface drainage in rain events. Model simulation indicated that net runoff load of total nitrogen （TN） from the paddy field was increased by WSI. Meanwhile, net runoff loads of total phosphorus （TP） and total organic carbon （TOC） from the paddy field was decreased by WSI. Because ponding waters of the study fields were enriched with TP and TOC, WSI reduced runoff of these nutrients by controlling the volume of surface drainage. WSI could be considered an efficient method for reducing runoff loads and could conserve water quality in an agricultural watershed.展开更多
基金supported by the National High Technology Research and Development Program of China (863)(grant no.2007AA06Z220)Important Project of the Ministry of Education(grant no.307014)the Huainan Mining Group program
文摘Based on the production data of a large number of surface drainage wells in the Huainan mining area,the present study shows that four types of typical production characteristics for relieved methane wells are recognized,of which the stable type for production and gas concentration is the most dominate,as determined by a comprehensive study on the volume and concentration of drained gases, as well as the stress changes of rocks influenced by mining.Some influence factors for the productive differences of the drainage wells were also been discussed.The results indicate that protective coal-seam mining has a significant effect on overlying strata,which promotes the development of pores and fractures of coal reservoirs for methane desorption and migration;however,the production and the stability of drainage wells are affected by deformation and damage of the overlying strata.The second distribution of strata stress is caused by mining engineering,and if the stress load is larger than the carrying capacity of the extraction well,the gas production would be influenced by the drainage well that has been damaged by rock movement.Furthermore,the case damage occurs first in the weak, lithologic interface by its special mechanical properties.The stability of drainage wells and the production status are also influenced by the different drilling techniques,uneven distribution of gas concentration,and combination of gob gas and methane from the protected layer.
文摘The purpose of this work is to study the effect of a type of water-saving irrigation （WSI） on nutrient runoff of paddy field. The volume of surface drainage was maintained low by WSI. In particular, WSI effectively reduced surface drainage in rain events. Model simulation indicated that net runoff load of total nitrogen （TN） from the paddy field was increased by WSI. Meanwhile, net runoff loads of total phosphorus （TP） and total organic carbon （TOC） from the paddy field was decreased by WSI. Because ponding waters of the study fields were enriched with TP and TOC, WSI reduced runoff of these nutrients by controlling the volume of surface drainage. WSI could be considered an efficient method for reducing runoff loads and could conserve water quality in an agricultural watershed.
