Analysis of Noise at Coal Face by Fully-Mechanized Coal Winning Technology

Jun.2003Analysis of noise at Coal Face by FullyMechanized Coal Winning TechnologyLIU Zhao-peng(刘照鹏)Department of Engineering, Cao Tang Branch, Sichuan Normal University Chengdu, Sichuan 610072, ChinaAbstract: The noise level of coal face by full-mechanized coal winning technology was measured in a coal mine. Andthen it was analyzed and evaluated using environment science ergonomics and fussy mathematics analysis. Basis of thestatistics and analysis of the measured noise level some measures such as applying the new materials and improving theconstruction of the equipment were carried out. The resuts show that they can reduce the noise level improve theworking environment and enhance the work efficiencyKey words: noise, coal face ;fully-mechanized coal winning technology analysisCLC number: TD 823. 97: TH 113. 1 Document code: A Article ID: 1006-1266 2003 X1-0113-04ipments working in the narrow and small1 Introductionspace. Therefore the noise is particularly serieThe noise is one of the main contaminative Table 1312. It is necessary to analyze,evaluatesources so the control of noise is in urgent need. At and control the noise then to improve the environthe coal face using full-mechanized coalment of the coal face and to enhance the efficiency oftechnology there are some big machinery power e- productionTable 1 The noise level in a coal mine(1.0 m from the noise sourcecavating coal machineScraper conveyorCaving the roofCrusherPump roomBelt conveyorCutting Empty Burdened EmptyRunning Idling Burden Empty Machine head Central2 Analysis and Synthesize Evaluation of the noiseUnder the different ratio about signal to the2.1 The influence of noise onnoise at a coal face the frequencies of the instruc-munication at a coal facetion that can be heard to lock the communication oneThe language communication can be coverd time have been obtained Table 2)with the noise. In order to get the right informationTable 2 The heard frequencies in the differentof language in the noise environment a ratio of lanratio of signal to the noiseguage and noise is usually usedL SIN=L((N)Test itempy-20pRight(1) Right frequency number 20Morewhere: P, is language voice pressure, Pa; po is basis Feel senseHave DifficultEasy influencedifficultyvoice pressure Pa;P is noise voice pressure PaMistake rateLp is language voice pressure class ,dB( N\vp Is2noise voice pressure class dB (A). L(S/N)TH中国煤化工34CNMH Gts well the frequencygenerally larger than 10 dBcharacteristic and subjective sense of a man s ear toReceived date: 2002-13-24Biography: LIU Zhao-peng 1963-), male, from Dali, Shanxi province associate professor, master engaged in the research on coal winning万序数搪114Journal of China University of mining technologyVol 13 No. 1noise. This is a good evaluation index for consecu- Then the voice pressure class LAi can be obtainedtion stabilizing noise. But the source of noise of theApplying above meOCoal face is fixed( for examplethe equivalent Amoving transformer substation the machine head of noise for four kinds of fully-mechanized coal winningthe scraper conveyor etc )or moved for example, technology are shown in Table 3the coal winning machine caving the roof moveTable 3 The measured equivalent a voice classplank etc), and mostly it is not stable noise( workin the different coal faceing state and racing state ) Therefore the equivalentFully-mechanized coalA voice class is used as comprehensively evaluating winning technoloCommon HighBig powerthe noise level of working environmentThe definition of the equivalent A voice classLo is that a unstable a voice class is used as an e-According to the noise quantity grade, whethe Lu is more than 75 dB (A), its type is the 5thquivalent a voice class with the method of averagegrade, and the quantity is worse. From Table 3energy in a period of time at a certain position in thebecause every grade of the noise exceeds the Sthcoal facegrade at the completely mechanize caving faces,the(2) environment quantity is very bad. Therefore thewhere: Lo is the equivalent voice class ,dRA:T valid measures must be used to control the noiseis measuring interval time by random choose La is2.3 Establishing the subordinated function ofinstantaneous a voice classnoise factorDuring measuring La is divided into severalTake a rang of the voice pressure class U=[090 ]. Then making use of fussy mathematics thezonessubordinated function of noise can be 4]La=10d∑(1101)],(where: pi is the ratio between the time of the j0.025L-1.2570≤L≤90voice class zone LAi is the center voice class value10102-0.95014(4)in the j zone,dB (A);N is zone numbe20≤L0≤50Some noise sources are movable. Taking the 2.4 The influence of the noisecoal winning machine for example the noise levelstalityof it have working state and racing state. At a cer- 2.4.1 The effect of the noise to persons agonytain point the noise level gradually dies down whilegreethe coalmachine keeps away from this pointThe degree of a certain strength noise to personwith the lapse of time. To measure the noise of acertain point in different time the coal face was diI=0.1058LA-4.798,vided into several parts. Every part is 10 m andwhere: I is the agony index( table 4) La ismeasuring time is T minutes for per certain pointenvironment noise strength, dB(A)Table 4 The agony indexExtreme agony2.4.2 The influence of the noise on conversationThe influence of some strength noise on converH中国煤化工 alysisCN MHGof the noise level atsation Is1.0 m from the noise source in a certain coal mineOut of hearing words( %)=0. 1989 LA-11. 47. its subordinated function value agony degree,out(6) of hearing words have been computed out and it canbe seen in table 5LIU Zhao-peng et alAnalysis of Noise at Coal Face by Fully-Mechanized115Table 5 The subordinated function value of the noiseNoise sourceWorking stateSubordinated function valuegony index Out of hearing wordsCoal winning machineMowing5.047,03%Empty0.8754.205.44%Scraper conveyorBurden6.109,02%Empty6.43%Put a coal0.9756.23%0.8755.44%PWorking6.109.02%Empty7.23%Belt transporterMachine head105Central part04%According to analyzing the above data, when faces with full-mechanized coal winning technologythe equipments are working in the coal faces with Three main factors of causing noise are the voicefully-mechanized coal winning technology its subor- source the spread path and the reflexive condidinated function value is equal to 1. It shows that the tions. So to control the noise, these three aspectnoise degree of the equipments is very seriousmustWhen the equipments operate the agnoy indexes 3. 2. 1 Managing the noise sourceare far in excess of 5. It means that the workers feelOnly by controlling the noise source can we reery agnoy and are weak in response. On the other duce the noise. It is more difficult to reduce thehand by talking the words about 10% couldn't be noise at the noise source because it is restricted byheard and people could only depend on the guess or all kinds of conditions and the environments. Therethe posture language to communicate with each othfore some techniques reform to the noise source willer. The mistakes and the operation errors can be be adoptedproduced. Therefore the effective measures must be1) Applying the new material and improvingadopted to control and reduce the noise in the coal the construction of the machine equipments. On thefaces and in order to improve the efficiency of the completely mechanize equipments the original partsworwill be replaced by the machine parts that have the3 The measures to Control the noisebig insides friction high damp metal alloy and high3. 1 The allow standard of the environment noise strength plastics. The current wheel gear can be ren order to control the environment noise pollyplaced by the nylon wheel gear, and it can reducetion and make it being harmless for the workers the noise 20 dB. Another measures are: Choosing< The Environment Noise Pollution Prevention and the low noise equipments optimizing the transmisCure Method )has prescribed the noise standard for sion mode, and as far as possible choosing the lowindustry enterprise 5]. The 447th rules in the safe noise transmission mode. Because the leather beltregulation of coal mining is that the noisecan reduce vibration and increase damp, the leatherork location in the pithead and pit bottom should belt transmission to replace the general wheel gearnot exceed 85dR A ) If the noise can't still meet can reduce the noise 16 dB. For the wheel gearthe standard adopting the measures the noise can be transmission equipments to choose the reasonableextended to 90dB( A ) While the noise exceeds line speed ratio can also reduce the noise 7)90dB (A), the things for individual protection中国煤化工 hod. Before thshould be used. [ 6JC MH Ghe coal, the water i3.2 The way to control the noiseemitted to the coal wall in advance. Then the coalThe control of the noise can obtain a good result seam is soft, and the rub between cutter and coalin accordance with the specific conditions and will be reduced. The noise caused by smashing betaking note fe synthesize measures at the coal tween the big pieces of coal and the scraper conveyor116Journal of China University of mining technologyVol 13 No. 1can be avoided. At the same time the dust could be time of the workers in the noise environmentreduced, and the work environment can be im1) By analysis and evaluation to a completely3)Strengthening maintenance. To maintain of mechanize caving face the problems of the noisethe machine parts should be enhanced. The injured have been discussed, the concrete measures to reparts should be replaced on time and the loosened duced the noise have been pcan lead toparts should be fastened so as to reduce the noiseimproving the production andhealth of the3.2.2 Controlling the radiation of the noiseworkersOn the usage, the closed cover will be installed2)The noise not only harms the human bodyto insulate the noise caused by the coal winning ma- but also affects the work efficiency. The syntheticchine and the transporter. The elastic materialmeasures to control the noise should be adoptedfilled to insulate vibration caused by the scraper then the good result can be obtained. Now, becausetransporter. The colloidal material is brushed to the of the limit of technique and economical term etc, itexterior of the machine so as to gain the rub between is difficult to guarantee the comfortable work enymaterials and consume the energy of the machine ronment. Under these circumstances, the premise isplank vibrationsthat the work environment should not harm the3.2.3 Adopting the personal protectionr's health. The workers in the completelyThe personal protection is a kind of economic mechanize caving faces must use the personal protec-and effective measure. The workers must wear the tion tools which is the most effective method to re-protection tools at a fully mechanize caving face. duce the harmful influence on the workersThe protection implements with different materials3) Ergonomics makes the machine and environhave attenuation functions for different frequement system suit the person s physiologic characteroise. Therefore the proper protection tools should istics and get the purpose of high-efficiency safe-be selected according to the different frequency char- ty health and comfort in the production the appliacteristics of the noise. The system of working in cation of ergonomics is very extensive which shouldshift should be practiced in order for reducing the be popularized in the coal industryReferences1]徐志胜煤矿人机系统可靠性研究D]成都西南交通大学管理学院J995.[2]朱序璋.人机工程敩M]西安西安电子科技大学出版社,1999[3]周美玉.工业设计应用人机工程茕M]北京中国轻工业出版社2001[4]龙升照人一机-环境系统工程研究进展(第四卷ⅠM]北京北京科学技术出版社J999[5]弈勇煤矿安全规程实施手舭M]北京中国商业出版社2002[6]中华人民共和国能源部煤矿安全规稙S]北京煤炭工业出版社1992[7]李耀中.噪声控制技朮M]北京北学工业出版社2001.[8]张义儒煤矿机械安全原理M]徐州中国矿业大学出版社,1988H中国煤化工CNMHG