綜合機(jī)械化采煤工作面的充填技術(shù)和地層運(yùn)動(dòng)外文文獻(xiàn)翻譯

英文原文Backlling technology and strata behaviors in fully mechanized coal mining working faceZhang Qiang, Zhang Jixiong, Huang Yanli, Ju FengA、School of Mines, China University of Mining & Technology, Xuzhou 221116, ChinaB、State Key Laboratory of Coal Resources & Mine Safety, Xuzhou 221008, ChinaAbstract:Based on the principle of fully mechanized backlling and coal mining technology and combined with theXingtai Coal Mine conditions, we mainly optimized the coal mining equipment and adjusted the coalmining method in the Xingtai Coal Mine 7606 working face for implementation this technology. Firstly,we dene the practical backlling process as the (from backlling scraper conveyors) head to tail back-lling, step by step swinging up of the tamping arm, gradual compacting, moving formed backlling scra-per conveyor when the second tamping arm cannot pass and connecting the immediate roof by back material push front material movement. Meanwhile, the stress changes of backll body in coal minedout area was monitored by stress sensors, and the roof caving law was analyzed by monitoring thedynamic subsidence of 210 west roadway of this face. The site tests results show that using this new backlling and coal mining integrated technology, the production capacity in the 7606 working facecan reach to 283,000 ton a year, and 282,000 ton of solid materials (waste andy ash) is backlled, which meets the needs of high production and efciency. The goaf was compactly backlled with solid material and the strata behavior was quite desirable, with an actual maximum vertical stress of the backll body of 5.5 MPa. Backll body control the movement of overburden within a certain range, and there is no col- lapses of major areas in the overlying strata upon backlled gob. The maximum subsidence and speed were 231 mm and 15.75 mm/d respectively, which proved the practical signicance of this integrated technology.Keywords:Fully mechanized backlling and coal mining technology，Hydraulic support，F(xiàn)ormed backlling scraper conveyor，Backlling technology，Strata behaviors1. IntroductionChinas economy is continuously depending on the coal energy.The coal production in China has increased rapidly in recent years,however, the other resources and environment are affected seri-ously. As an example, coal waste is a kind of solid waste discharged from coal exploitation and preparation. This waste pile on the sur-face and form waste dumps over the time. According to the partial estimates, there is about 4.5 billion tons of waste rock piled on the surface in China, and about 15,000 hectares of land are occupied.There are 1600 comparatively large waste rock dumps, and the piled waste is increasing at a speed of 0.150.20 billion tons a year.Waste dumps have not only occupied too much land, polluted the air, soils and underground water around them, but also have caused potential dangers, such as landslide, spontaneous combus-tion and explosion. So it is a severe threat to the peoples health and environment in mining districts.If the condition is such that the roof will not cave or subsidence to the surface is not allowable, it will be necessary to backll the void with materials such as sand, waste from coal-preparation plants, or y ash. Owing to technical and environmental reasons,backlling is practiced in many mining countries (e.g., Poland,India), but the unit cost of coal mining is much higher with backlling.Up to date, there are three main mature backlling technologies in China which are; super high-water packing material backlling,paste backlling and solid material fully mechanized backlling coal mining technology 1. Some literatures studied the experi-ments and applications of super high-water packing material. Some articles studied mining method and coal winning tech-nology of paste backlling. Zhang et al. studied the strata pressure behavior of raw waste backlling with fully-mechanized coal mining technology. As a new backll technology in coalmine, the solid material fully mechanized backlling coal mining technology is developing day by day.This technology has been applied in Xingtai Coal Mine, Jining No. 3 Coal Mine in China. Its applications have conrmed distinc-tive advantages on extracting coal under water bodies, railway lines and buildings and controlling the surface subsidence.This is its major difference compared with traditional fully mechanized coal mining methods. To the best of our knowledge, there are sel-dom researches on backlling and coal mining technology. This article mainly introduces this technology from the above two points based on the mining conditions of Xingtai Coal Mine.2. Basic principles of fully mechanized backlling miningIn fully mechanized backlling mining, we usually use waste rock, y ash and other solid materials as the backll materials.We use the vertical continuous conveyor system to transport such solid materials from the surface to the underground, and then through the belt conveyor transportation to the backlling work-ing face. We take the advantage of the backlling device to achieve the lling process. The basic principles of a fully mechanized back-lling mining is shown in Fig. 1 16,18,19.3. General information of 7606 working face3.1. Geological conditions7606 backlling and coal mining face are therst solid material fully mechanized backll mining faces in China. This face extracts 2# coal seam, which has an average inclination of 9, average height of 3 m and depth of 320 m. The lithology of the roof is sandy shale with height of 4.5 m and the oor is sandy shale with height of 6.69 m.The face is located in east of underground in the 6th mining area. Its northeast is near the goaf of 7602 working face, northwest near to F10 fault, south is 50m away from 210 west roadway and east is 100 m away from shaft bottom.3.2. Backlling system layoutThe tailgate of the 7606 backlling working face is 40 m away from F10 fault, and the headgate is parallel with tailgate connect-ing with 7600 transportation line. The interconnection is 50 m away from the west roadway and the stop mining line is set at least 35 m away from west roadway. The incline width and strike advancing length of 7606 backlling working face are 50 and 460 m, respectively, and the available coal reserve is 115,000 ton.Backlling system is made of four parts including surface trans-portation system, vertical feeding system, underground transpor-tation system and stope lling system. The backlling ability of this system is 450 ton/h.The backll materials in this face are wastes and y ashes. The wastes come from the waste dump with capacity of 380,000 m3,and y ashes come from coal preparation plants with capacities of over 37,000 m3a year. These two materials are mixed by mea-sure instructor before being thrown into vertical feeding system.Then, the mixed backll material is transported to storage silo underground by vertical feeding system, then in turn to 7606 back-lling working face or 7606 tailgate through haulage rise.4. Coal mining and backlling technology4.1. Key equipmentA variety of equipments are used in a surface mining operation including shearer,scraper conveyor,hydraulic support, self-advancing backlling loader and backlling scraper conveyor,which are among the key equipments used in 7606 working face.There is no difference on determining the shearer type in this backlling working face compared with the traditional fully mech-anized coal face. But for hydraulic support, we have known that the roof is supported by mechanized self-advancing supports called longwall shields, which form a protective steel canopy under which the face conveyor, workers, and shearer operate. So except for meeting the need of coal mining, it is also needed to meet back-ll demand. In details, there must be a space in the back of hydrau-lic support for the backlling structure, and the tail beam must be of certain strength for hanging the backlling scraper conveyor,and there must be some additional structures for unloading and tamping backll material.At the end of the tailgate, materials are transshipped from belt conveyor to the backlling scraper conveyor by self-advancing backlling loader, which has an H shaped frame and supports the base at the overlap where it connects with belt conveyor.For the implementation of fully mechanized backlling mining technology, we formed a general scraper conveyor by the following ways: (1) setting up an additional ashboard controlled by a hydraulic cylinder jack at its bottom, (2) opening the discharge port at its bottom, (3) self hanging up on a rear canopy of hydraulic support with hanging chains. The formed scraper conveyor can meet such special need.Based on the actual situation of Xingtai Coal Mine, and through science and technology research, the backlling and coal mining equipment mainly in the 7606 working face are obtained in pairs as follows, MG200/466-WDH shearer, SGZ-630/220 scraper con-veyor, SGB630/150 self-advancing backlling loader, SGB630/150 formed backlling scraper conveyor and ZC6000/20/35G four-post shield-type hydraulic support. The equipment layout in this back-lling and coal mining working face is shown in Fig. 2 18,19.4.2. Coal retreating technologyThe coal is extracted by strike longwall method with one pass cutting coal mining process. The sequence of operations continues with support of the roof at the face and shifting of the conveyor forward. Coal cutting is bidirectional by a double-drum shearer with web cutter of 0.6 m. The advancement of the hydraulic support follow closely behind shearer, and the fourth hydraulic support behind the back roller of the shearer advance rst to support the immediate newly exposed roof after coal removal. The scrapers which load the broken coal onto a conveyor begin to advance from 15 m away behind the back roller of shearer after coal removal. The facesupportisashield-typehydraulicsupport,withafour-postand self-ram-type face ends, which uses ZZC4800/16/32 end support to maintain the operation space. DW-32 double single hydraulic prop is used as advanced support.4.3. Backlling technologyThe backlling works are completed mainly by backll mining conveyor and tamp mechanism. Backll mining conveyor is used to transport backll material and unload it from the discharge port with itsashboard at its bottom. There is one discharge port under each tail beam of the hydraulic support. Tamp mechanism is the key structure in the backlling process, which includes two tamping arms (the rst and second tamping arms) controlled by hydraulic cylinder jacks. The function of tamp is to push and compact material to connect immediate roof with demanded density.In general, tamp mechanism can enforce about 2 MPa of compaction force on backll body when therst and second tamping arms are fully extended.4.3.1. Backlling processThe backlling process operates from tail to head of the backll mining conveyor. So materials are also transported along this way by backll mining conveyor. When the materials are ofoaded from the current discharge port packed to a certain height, the rst and second tamping arms situated besides the discharge port immediately start in 0 n.l9rge1p9to-275.-he discharge port the head to tail of the backll mining conveyor orientation,open 35 ashboards to ofoad the materials. Tamping and ofoading are alternately carried out at the same time behind hydraulic supports.(2) Firstly, we dene one crop as the quantity of running material between every two discharge ports. To one unloading and tamping course, when the material is being ofoaded,about three other crops are close to the discharge port and begin extending the rst and second tamping arm to push material in turns. When the second tamping arm is fully extended, stop operating the operation valve and retractthe tamping arms. Then slightly swing up the arms and fully retract the rst tamping arm when the end of the second tamping arm is at the bottom edge of the backlling scraper conveyor. Then appropriately swing up the arms again until the bottom edge of arm is in touch with the material face and then fully retract the second tamping arm. Care should be taken to ensure that no materials are brought back along with the tamping arms. Then swing down the arms and wait for the next ofoading and tamping course. As the materials are gradually packed, tamp mechanism is automatically uplifted to a certain angel after recycling 35 times, which automatically stops the second tamping arm to across from the bottom edge to the backlling scraper conveyor. Thus,the rst tamping course is completed together with the rst and second tamping arms.(3) The second tamping course is completed only by the rst tamping arm. In this course, when material is being ofoaded, about two other crops are close to the discharge port and directly push the rst tamping arm to compact the material until the front material has been pushed compact, retract the tamping arm, and then repeat the process again. After recycling 35 times, fully retract the rst tamping arm and off- load material until the space under the backlling scraper conveyor is fully lled, then go to next tamping course after backlling scraper conveyor is advanced.(4) The third tamping course follows when the second tamping course has nished in the entire backlling face. At rst,advance the backll mining conveyor from tail to head, but at the same time, as the conveyor is advancing, carry out the connection of the immediate roof course by pushing the material. This is done rstly by appropriately adjusting the tamping arms angel, and then extending the rst tamping arm and later the second tamping arm. The front material is then pushed to connect the immediate roof by the back material which is also being pushed tightly by the second tamping arm. If the roof connection is not completed,then complete it in the last tamping course by repeating the process, or else, the entire backlling face tamping course is completed.(5) The forth tamping course is the leaklled section, where the two tamping arms are fully retracted after ofoading about two or three crops of material, and then extending the two tamping arms again to connect with the immediate roof.And a tamping course of one hydraulic support is completed.Then when all hydraulic supports are backlled with material to a certain density, advance the hydraulic support and a tamping course in one web cut is completed. The details of unloading and tamping courses are shown in Figs. 4 and 5. Fig. 4 illustrates the backlling elevation in the working face and Fig. 5 shows the different backlling states in working face.5. Strata behaviors5.1. Measure content and methodSome literatures (Chen et al. 2010)20 used the convergence of roof andoor and post load as the characteristic parameter of strata behaviors in waste lling conventional surface. This paper uses stress of the backlling body and dynamic subsidence law of the roof as the key parameters for strata behavior analysis in fully mechanized backlling and coal mining working face. The stress of backlling body is acquired online by stress sensors installed in the goaf. The dynamic subsidence law of roof is obtained indirectly from the observation points set in oor of the 210 m west roadway upon this face. The stress sensors are installed in the rst,second and third rows of the goaflled with backlling body when the coalface advances 15, 40,65 m away from the interconnection.The installation condition is shown in Fig. 6. The 210 m west roadway is 40 m away from the interconnection, and 27 m directly above 7606 working face. We arranged 29 observation points along the sloping direction of the face to timely monitor the rock movements. The 10th to 20th observation points are installed just above 7606 working face. The layout for observation points is shown in Fig. 7 21.5.2. Results and discussion of eld measurement5.2.1. Backlling body stress monitoring results and analysisFrom theeld measurements, with the forward advancement of working face, the roof pressure behind the working face was at rst supported by hydraulic support and rib, but then gradually transferred to the backlling body. When working face advanced to the caving distance of main roof (about 15 m), the speed of caving of immediate roof increased and the backlling body was compacted by immediate roof. The stress sensors in backlling body started to sense pressure in places about 1315 m behind the working face. In the second row (40 m away of the interconnection) of observation points, the maximum stress measured in back(3) We carried out three operation units and cut webs (each cut web of 0.6 m), and the coal face advanced forward 3.6 m in 1 day. The production capacity of this backlling mining face is 283,000 ton (330 6 0.6 50 2.79 180 0.95). And about 282,000 ton of solid materials are backlled in one year, whichmeet the needs of high productionand efciency.(4) After implementing this technology in 7606 face,115,000 ton of coal is mined safely and over 0.82 billion (unit: Yuan) is directly obtained.(5) Inuenced by the mining pressure, the overlying strata upon 7606 working face experienced a lightly subsidence process.The maximum subsidence quantity and speed are 231 mm and 15.75 mm/d, respectively. This shows that the backlling body controls the strata movement to a certain extent,and there is no large area of the roof that appear to have collapsed upon the working face.AcknowledgmentsFinancial supports for this work provided by the National Natural Science Foundation of China (No. 51074165), the Key Program of National