Mining Noise Hazards

[Music] [Applause] hearing loss noise exposure has been added to the long list of occupation health and safety problems confronting many Industries today noise is any loud sound that is intrusive irritating or undesired it has been long known by both doctors and workmen that prolonged exposure to loud noise produces death but only recently his industry seriously recognized it as a crucial health and accident hazard loud sound that is intrusive irritating or undesired it has been long known by both doctors and workmen that prolonged exposure to loud noise produces death but only recently has industry serious ly recogniz it as a crucial health and accident Hazard noise can become a very real aess Hazard if the level or loudness is sufficiently high to interfere with speech reception voice signals or the transmission of instructions or other auditory signals noise can distract a man at his JW and it can drown out or mask warning [Music] [Music] signs hearing is the special sense by which noises and tones are re a stimuli in the process process of hearing Airborne sound waves are collected by the external ear and conducted through the auditory canal to the eardrum at the eardrum the pressure variations of sound in air are transformed into very minute mechanical vibrations that are then transmitted by three bones of the middle ear the hammer Anvil and Stirrup to the oval window the movement of the oval window sets up wave motions in the fluid of the inner ear which are sensed by the hair cells in the cocka the compression tension and bending hairs transforms the mechanical Sound Vibrations into electrical impulses these impulses are then transmitted from the actic nerve to the brain transformation of sound to electrical nerve is largely dependent upon the hair cells considering the minute size of the hair brush it can be easily understood that if the amplitude of the vas brain vibrations becomes too large as induced by Exel noise the resultant severe mechanical stresses cause the hair cells or their bristles to fatigue lose their and their ability to return to their normal position this gives way to deterioration or monocellular Decay or in other words a gradual loss of hearing as the result of destruction of structures in the inner ear as we grow older our ears gradually become less sensitive to sound this normal loss of hearing due to aging is called prusis hey John watch out look for the car permanent loss appearing due to excessive exposure to noise is greater than that which results from aging various factors contribute to noise induced hearing loss one is the overall noise level another is the composition of the noise its frequency tone or impact a third factor is the duration frequency and distribution of noise exposure during a typical workday and total exposure time during a work [Music] life and fourth is the susceptibility and sensitivity of the the individual ear itself some people may have more sensitive or Tender ears than others and may more easily incur some degree of hearing [Music] loss there is little doubt that a major cause of hearing loss today is overexposure to excessive noise but there is a difference in noises for example even though two different noises may have the same overall loudness intensity or sound pressure level their compositions or spectrums may differ to such an extent that one of them may produce a permanent hearing impairment while the other may not the reason for this is frequency or pitch at the higher frequencies human hearing is most sensitive and most susceptible to damage when subjected to excessive noise the low frequency noise we can tolerate because our ears naturally discriminate against low frequency sounds most beginning noise induced hearing losses occur at frequencies above the normal speech frequency therefore it is vital to control higher frequency noises because the first indication of hearing loss which can be expected at around 4 th000 Cycles is quickly followed by noise induced hearing losses in the lower speech important frequencies generally the louder the noise and the longer the ear is exposed to it the greater the hearing loss according to current medical opinion noise energy having predominant frequencies above 500 cycles per second are a greater potential for causing hearing loss the noise in the low frequency [Music] region in addition It is believed that intermittent exposures are far less damaging to the ear than continuous exposures even if the intermittent sound pressure levels are considerably higher [Music] an extremely loud noise May rupture the eardrum or destroy the ular chain but such catastrophic noises are usually predictable and we can prepare for them [Music] in order to control noise exposure accurate information defining the extent duration and distribution of noise exposure at the work site is [Applause] needed to measure noise or sound levels An approved and acoustically calibrated sound level meter is used the sound pressure level or intensity of the sound measured is expressed in Deb DB which is a unit for indic ating the relative loudness of sound the range of loudness ordinarily detectable by the human ear starts at 1 DB for the faintest audible sound and extends to around 115 DB for the loudest permissible sound present noise standards set by the Walsh heliac permit 8 hours of exposure at 90 DB and shorter periods of time at louder levels up to 115 DB total duration of exposure alive at 115 DB though is only 15 minutes another device designated to measure the total noise to which a worker is exposed for a workday is the noise dosimeter exposure throughout the day is recorded on a memory cell at the end of the shift the dosimeter is inserted into a readout device the workers daily noise exposure is then displayed as a percentage of the allowable limit established by the noise standards the memory cell is automatically cleaned for reuse as the exposure information is retrieved different occupations in mining expose individuals to different ranges of sound levels for example men riding man trips are exposed to sound levels ranging from 74 to 100 D shuttle car operators are subjected to sound levels of 90 to 98 DB when [Music] loading and 85 to 92 DB when tramming [Music] a cutting machine operator is exposed to sound levels ranging from 93 to 98 DS when suming in continuous mining oper operations produce sound levels of 89 to 107 DB during the cutting and loading [Music] [Music] cycle a loading machine operator is exposed to sound levels ranging from 90 to 108 DB and a Pneumatic roof Bolder produces sound levels between 104 to 118 DB when drilling surveys disclosed that several underground coal mine occupations exposed workmen to sound levels that resulted in shift noise exposures above the maximum allowable level established by the Walsh helc this confirmed earlier suspicions that a noise problem did exist in underground coal mining but what can be done about the problem once noise measurements have been made when employees are subjected to sound levels exceeding those listed in the table of permissible noise exposure then an effective hearing conservation program must be provided by the mine operator feasible engineer ing or administrative controls must be utilized or personal protective equipment must be made available to workers underground mining seldom lends itself readily to the adaptation of materials or methods necessary for noise abatement either at the noise Source or in the hearing zone of the worker but noise reduction by engineering control procedures can be accomplished in many instances for example reducing the sound intensity at the noise Source might be accomplished by substituting quieter equipment such as using a rotary drill in place of a star drill and air hammer type or if air operated Machinery is used appreciable reduction of sound can be achieved by muffling the exhaust of the machine or by piping the exhaust to a distance where the noise is not objectionable most mining equipment was not designed with noise suppression as one of the Prime considerations therefore when new equipment is ordered complete noise level specification should be furnished to manufacturer the Bureau of Minds is cooperating with manufacturers in developing and testing quieter operating mining [Music] Machinery maintenance is another important element in noise control by replacing or adjusting and loose the r balance Parts keeping tools properly sharpened and cleaned and by vly using lubricants cutting oils existing Machinery can be kept in quieter operating [Music] condition controlling noise at the source is the ideal means of preventing noise induced hearing losss but if noise cannot be reduced to permissible intensities through engineering controls then administrative controls should be developed to limit duration of workers's exposure this method is involves arranging work schedules or rotating Personnel to reduce the amount of time spent in noisy areas employees working the major portion of a day at 90 DB or above and who have reached the upper limit of duration for a high noise level should be rotated to work the remainder of the day in an environment with a noise level well below 90 DB [Music] remote control TV Camera can be used to reduce the time of noise exposure by allowing operations to be monitored away from the noise producing areas when both engineering and administrative controls fail to reduce noise or duration of workers exposure below the permissible levels the use of personal protective equipment is advisable when necessary mine operator must Supply such equipment and employees must be instructed in its use and encouraged to wear it this way and they have a top in the bottom is the only thing you really have to remember get that top up so that the band goes behind the head and that keeps it away from your use S encourage to wear it this way and they have a top and the bottom is the only thing you really have to remember get that top up so that the band goes behind the head that keeps it away from your land cord and your hard D they try those on they go on that way pop up once you get it on you push in in the back with nice and tight as you can have it on it feel good it's fine all although occupational noise exposure regulations presently require both provision and use of personal protective equipment its use is considered by most acoustical experts to be only a Nim measure while engineering and administrative controls are being [Music] perfected another important aspect of a hearing conservation program is pre-employment audiometric hearing tests for employees you are going to hear some sounds some will be high and some will be low but most of them will be very faint these tests provide a guide for placing new employees early detection of a hearing problem will avoid putting a man on a job where he may be exposed to excessive noise or where he may not be able to hear warning signals or instructions this may prevent a tragic and costly accident do you hear better in one ear than the other all right let's begin periodic checkups or follow-up audiograms to detect changes in the status of an individual's hearing should be conducted as prescribed by the company physician the determination of the extent of hearing loss involved rests finally with the physician follow-up tests can also be used to assess the effectiveness of the noise control program most hearing losses developed gradually no pain is involved nor is there much interference with communication and individual may not realize his hearing is being impaired Mr fitler Mr figher he doesn't get used to noise he just hears less of it if necessary steps are not taken the deterioration of hearing soon becomes permanent any meager compensation payment cannot offset the hardship of hearing loss to otherwise healthy person the effectiveness of a hearing conservation program depends upon the cooperation of employers employees and others concerned it is Management's responsibility to conduct noise measurements and surveys initiate noise control programs inform employees of the benefits to be derived from a hearing conservation program and provide hearing protection equipment in areas where it is recommended it is up to the employee to make proper use of the equipment provided by management and to observe any rules or regulations in the use of this equipment to minimize the noise level [Music] exposure the importance of this responsibility is expressed more explicitly by section 206 of the federal Coal Mine health and safety act of 1969 which states on and after the operative date of this title the standards on noise prescribed under the Walsh hey public contracts act as amended in effect October 1st 1969 shall be applicable to each coine and each operator of such mind shall comply with them [Music] a [Music]