Wang G.,Hebei University of Engineering |
Jiao S.,Hebei University of Engineering |
Cheng G.,Jizhong Energy Group Co.
Energy Exploration and Exploitation | Year: 2011
In view of the present situations and existing problems of thin coal seam mining under complex geological conditions, low-profile mining equipment for fully mechanized coal mining was developed. This paper presents the study on the development of the equipment. The low-profile mining machinery includes the shearer, the scraper conveyer, the hydraulic powered supports and others. A highly efficient cutting system with a high-power mechanical drive was utilized to improve the rock breaking capacity. The ultrahigh-temperature laser cladding technology was applied in the cutting equipment for wear-resisting sparkless coal and rocks excavating, suitable for highly gassy mines. The lead-angle friction theory and the side-pushing principle of angled panel forward movement were applied in the development of the moldboard coalloading equipment. This development successfully achieved a coal-loading rate of over 98% and ensured smooth movement of the scrapper. Automation was implemented with electro-hydraulic technology and shearer remote control technology in main coal mining operations such as the movement of hydraulic support and conveyor. The automation enabled fast mining operations following the rapid movement of the cutting machinery. Furthermore, advanced computer simulations and optimizations were conducted to achieve optimal structural designs of the hydraulic powered supports. With the above development of low-profile mining equipment, fully mechanized mining of thin coal seams under the complex geological conditions was achieved. The development equipment has great potential to be widely applied in coal mines with similar conditions.
Jiang Y.,China University of Mining and Technology |
Lu Y.,China University of Mining and Technology |
Zhao Y.,China University of Mining and Technology |
Zhang D.,Jizhong Energy Group Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011
The occurrences of breakage and water inrush disasters of working face floor under mining above aquifer are increasing with the mining depth in China. Taking the working face floor above deep aquifer in Jiulong Mine as the research object, by means of the core extraction, drill core logging and laboratory testing, the distribution laws of aquifers and mechanical parameters of each rock stratum of the working face floor above aquifer are obtained. Meanwhile, the reliability of parameters are ensured. The similar simulation test for fracture instability characteristics of working face roof and floor during the mining above aquifer are carried out by the self-designed confined water simulation equipment. And the stress variation laws of the roof and floor during working face mining are obtained. Using the noncontact optical measurement technology, the whole field displacement contours are measured. Base on the 'down three zones' theory, the maximum failure depth of working face floor, the raise height of confined water and the thickness of effective confining rock strata in deep region of Jiulong Mine are calculated. The simulation results show that: the 'three zones' appear in deep working face floor above aquifer in Jiulong Mine; and the new confined water simulation equipment can simulate the process of water pressure relief.
Feng G.-M.,China University of Mining and Technology |
Sun C.-D.,China University of Mining and Technology |
Sun C.-D.,Jizhong Energy Group Co. |
Wang C.-Z.,China University of Mining and Technology |
Zhou Z.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2010
Based on the basic properties of super high-water material, the technology of goaf filling mining with super high-water material was studied out in order to liberate the coal resources under buildings. There are four types in the technology, including open filling, bag filling, hybrid filling and partition filling. Every type was analyzed detailedly, containing its filling process, advantages, disadvantages and applicable conditions. The results show that super high-water material is an ideal goaf filling material in a wet, cold and closed environment, and the material with its corresponding fill mining methods is one of the development directions of future goaf filling mining technologies.
Chu H.,Jizhong Energy Group Co.
Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery | Year: 2011
To discuss the surgery procedure and the clinical effectiveness of repairing skin and soft tissue defects in the lateral foot and the heel with the abductor digiti minimi muscle flap. Between July 2002 and October 2010, 8 patients with skin and soft tissue defects in the lateral foot and the heel were treated. There were 6 males and 2 females with an average age of 42 years (range, 28-65 years). The locations were the left foot in 5 cases and the right foot in 3 cases. Defects were caused by ulcer of the heel in 2 cases, by poor healing of incision after calcaneus fracture surgery in 1 case, and by crushing in 5 cases. The defect size ranged from 1.5 cmx 1.0 cm x 8.0 cm x 2.6 cm. The disease duration was 30 minutes to 26 months. The result of bacterial culture was positive in 2 cases. After 9 to 15 days of debridement and dressing change, defects were repaired with the abductor digiti minimi muscle flap of 5.6 cm x 1.5 cm to 7.6 cm x 1.8 cm at size. The donor site were sutured directly. Partial necrosis of muscle flap occurred in 1 case at 4 days after operation, which was cured by symptomatic treatment, and the other muscle flaps survived. All incisions of the donor sites healed by first intention. The muscle flaps survived and the granulation grew well at 9-21 days after operation, and the muscle flap wounds were repaired by free leg edge thickness skin grafting. Wounds were repaired by one-stage free skin grafting in 1 case and by two-stage free skin grafting in 7 cases; all skin flaps survived and wounds healed by first intention. Seven patients were followed up 9-18 months (mean, 11 months). The appearance, texture, and sensation were satisfactory. The two-point discrimination was 16-23 mm (mean, 19.5 mm). Epidermal abrasion occurred in 1 case of heel ulcer after weigt-bearing walking. Hallux valgus and muscle weakness occurred in 1 case of necrosis of the peroneus length tendons; and the satisfactory results were achieved in the other patients. It has satisfactory effectiveness to use the abductor digiti minimi muscle flap for repairing skin and soft tissue defects in the lateral foot and the heel, which has the advantages of easy-to-operate, safe, less injury at donor site, good appearance and texture, and good recovery of sensation.
Zhao Q.-B.,Jizhong Energy Group Co.
Meitan Xuebao/Journal of the China Coal Society | Year: 2014
Based on large mining deep mine deep coal seam and under-group coal seam mining influenced by ordovician limestone confined water threat situation and water keeping requirement in Hanxing mining area, regional advanced governance idea of ordovician limestone karst water with pressure mining water disaster governance and advanced initiative, regional governance, wholly transformation, mining with pressure guideline were put forward; Regional partition principle, management mode and suitable conditions, investigation and governance combined with new methods, advanced governance management procedures, floor block water proof capacity evaluation method and key technology governance and other supportive system were correspondingly gave. The whole set technology was put into study and application in Hanxing mining area, especially the ground multi-branch horizontal drilling key technology application research, which got excellent safe technology effect, innovated ordovician limestone karst water disaster governance in deep mining mines and under-group coal seam mining, mined out the coal resourced safely threatened by confined water and protected coal system basement ordovician limestone karst water environment.