operation impacts: inglis local reinvestment and
TRANSCRIPT
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Operation Impacts: Inglis Local Reinvestment and Employment (Slide 3):
1,600,000
;;; 1,400,000
~ 1,200,000 ! 1,000,000 UJ 800,000 § g 600,000
< 400,000 200,000
OPERATION IMPACTS: INGLIS QUARRY LOCAL REINVESTMENT AND EMPLOYMENT
Capital Expenditures
Fiscal Year
Capital expenditures forecast for 2006: . $1,300,000
Employment
3 Salaried Positions
52 Hourly Positions
I 55 Full Time Employees I
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Two of the most important direct impacts from the Inglis mining operation are the local capital expenditures and the local employment. Cemex invests around one million dollars a year in capital to make long term improvements at the quarry. Examples of these expenditures include quarry equipment such as haul trucks and loaders as well as improvements to the site such as fencing and office space. Many of these investment items touch local suppliers in one form or another. Beyond local reinvestment, the operation also employs fifty five full time employees. Of these positions, three are salary and fifty-two are hourly. The positions range from clerical work to managers to equipment operators .
Inglis Operation Impacts- Quarry Expenses (Slide 4):
INGLIS OPERATION IMPACTS- QUARRY EXPENSES
2004, 2005 and 2006E Expenditures from the Inglis Quarry
$3,500,000 ,------------------------,
$3,000,000
02004
•zoos
;;;; - $2,500,000
~ !. $2,000,000 )(
w iii ;:, c
$1,500,000
~ $1,000,000
$500,000
$0
Fuel Direct Labor Contract Labor Services and Rentals
Supplies
The Inglis operation accounted for more than $4.6M 2004, $6.8M in 2005 and is foreeast to spend $7M In expenses on Fuel, Labor, Services and Supplies
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In addition to the capital invested in long term improvements, the operation consumes • around $7 million annually in expenses. The major pools of expenses are shown in the table. Fuel consumption is over a half million dollars a year, more than $2 and a half million is spent each year on labor in salaries, wages and benefits as well as another half million which is spent on contract labor. Services, rentals and supplies account for another $1.5 to 2 million annually bringing the total expense number to around $7 million dollars. These expenses flow primarily through the local economy in the form of wages and local suppliers.
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Inglis Quarry Product Impacts in Local Markets (Slide 5)
INGLIS QUARRY PRODUCT IMPACTS IN LOCAL MARKETS
• Approximately 200,000 tons of course construction aggregate sold locaJJy!'l (4-5 ready mix plant locations supported)
• 200,000 tons of aggregates used to annually produce 225,000 cubic yards of concrete
• At 150 cubic yards per home!2l, 225,000 cubic yards will support the construction of 1,500 new homes
• 1 ,500 homes at $200klhome translates to $300M in annual impact in the home construction industry
• $300M in home construction activity leads to an estimated $636M of total economic activity generated!2J ·
• Without local sources, the cost of construction aggregate could increase by over $11 per ton (59%) for a total annual cost increase of $2.2 million!3l
1) 30 mile radius from the Inglis operation (primarily Citrus and Levy counties) 2) Cemex Inc. Planning estimate 3) Source: l)niverslty of Florida, College of Design Construction and Planning Report: Impact of Real Estate on the Florida Economy (2002) 4) Represerm additional freight cost assuming material sourced trom Tampa W'ia imports .
Beyond the direct impacts from the operation, the product from the Inglis quarry operation provides a vital component to the construction industry. Approximately 200,000 short tons of course construction aggregates are sold in Citrus and Levy counties from the Inglis quarry on an annual basis. This product is then used to produce about 225,000 cubic yards of ready mixed concrete. In terms of new home construction, this amount of concrete will support on average about 1,500 new hom:es (at an average of 150 cubic yards of concrete consumed per home). At an average sales price of $200,000, this would translate into about $300 million in annual local revenue generated by the home construction industry. Utilizing data from a University of Florida College of Design Construction and Planning, this $300 million then leads to an estimated $636 million of total economic activity that was generated through the construction and sales of new homes. The significant local economic impacts of construction aggregates is important to consider while noting that construction aggregates have a low value to weight ratio. This means that they are difficult and expensive to transport. We estimated that the cost of aggregates would increase by over 59% or $11 per ton if they were not available locally. On 200,000 tons of material this equates to an increase in annual costs of more than $2.2 million dollars .
Economic Impacts of the Inglis Quarry Summary (Slide 6)
SUMMARY OF THE LOCAL ECONOMIC IMPACTS OF THE INGLIS QUARRY
Inglis Quarry Operation
•55 Employees
• Annual expenses in excess of $7 million
• Annual community reinvestment of around $1 million
• 200 thousand tons of construction aggregate sold in local markets
• Estimated $636 million of total annual economic impacts in local markets
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In summary the Inglis Quarry operation plays a significant role in the local economy as a vital part of the construction industry. The operation employs 55 full time employees, invests around $1 million annually in capital improvements and spends more that $7 million a year on operating expenses. The production from this operation supports the construction industry with 200,000 tons sold locally which is used primarily as an ingredient in ready mixed concrete. These construction aggregates have an estimated annual impact to the economy of over $600 million by supporting construction activities .
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ECONOMIC IMPACTS OF THE INGLIS QUARRY
May 2006
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AGENDA
Overview of the Economic Impacts
Operation Impacts
Product Impacts
Summary and Questions
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• ECONOMIC IMPACT OF ~E INGLIS QUARRY •
Operation Impacts
Inglis Facility
Local Reinvestment Employment
Supplies & Services
The Inglis quarry operation influences the economy directly through local reinvestment, employment and the purchase of supplies and services.
Product Impacts
Construction Aggregate Production
I Ready Mixed
Concrete Production
I Construction Industry
Impact
I Greater Economy
Impact
In addition to the direct influence, the aggregate production from the Inglis facility is an important component of the local economy because it supports the construction industry as a raw material for ready mixed concrete.
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1,600,000
01,400,000 -c 1,200,000 ~ 1,000,000
UJ c 800,000
5 600,000
~ 400,000 200,000
OPERATION IMPACTS: INGLIS QUARRY LOCAL REINVESTMENT AND EMPLOYMENT
Capital Expenditures
2004 2005 2006F
Fiscal Year
Capital expenditures forecast for 2006: $1,300,000
Employment
3 Salaried Positions
52 Hourly Positions
I 55 Full Time Employees I
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-~ -Q) 0 s::: Q) Q. >< w -cu ::I s::: s:::
<C
I~LIS OPERATION IMPACf!- QUARRY EXPENSES •
$3,500,000
$3,000,000
$2,500,000
$2,000,000
. $1,500,000
$1,000,000
$500,000
$0
2004, 2005 and 2006E Expenditures from the Inglis Quarry
Fuel Direct Labor Contract Labor Services and Rentals
[J 2004
.2005
CJ 2006F
Supplies
The.lnglis operation accounted for more than $4~6M 2004, $6.8M in 2005 and is forecastto spend $7M in expenses Qn Fuel, Labor, Services and Supplies
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INGLIS QUARRY PRODUCT IMPACTS IN LOCAL MARKETS
• Approximately 200,000 tons of course construction aggregate sold locally(1> (4-5 ready mix plant locations supported)
• 200,000 tons of aggregates used to annually produce 225,000 cubic yards of concrete
• At 150 cubic yards per home<2>, 225,000 cubic yards will support the construction of 1,500 new homes
• 1 ,500 homes at $200klhome translates to $300M in annual impact in the home construction industry
• $300M in hom f). construction activity leads to an estimated $636M of total economic activity .generated<2>
• Without local sources; the cost of construction aggregate could increase by over $1 t per ton (59°k) for a total annual cost increase of $2.2 million<3>
1) 30 mile radius from the Inglis operation (primarily Citrus and Levy counties) 2) Cemex Inc. Planning estimate 3) Source: University of Florida , College of Design Construction and Planning Report: Impact of Real Estate on the Florida Economy (2002) 4) Represents additional freight cost assuming material sourced from Tampa via imports.
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s!MMARY OF THE LOCAL ~ONOMIC IMPACTS OF • THE INGLIS QUARRY
Inglis Quarry Operation
• 55 Employees --
• Annual expenses in excess of $7 million
• Annual community reinvestment of around $1 million
• 200 thousand tons of construction aggregate sold in local markets
• Estimated $636 million of total annual economic impacts in local markets
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Noise and Silica Exposures A Survey of Washington State Quarry Operations
The Mine Safety and Health Administration (MSHA) issued a new standard for hearing protection effective in September 2000. The new rule requires that mine operators enroll miners in a hearing protection program if they are exposed to an average sound level of 85 decibels (dBA) or more during an eight-hour period. In order to determine average sound level, workplace noise monitoring is required.
The Field Research and Consultation Group (FRCG) at the University of Washington received requests from ten open surface mines in Washington State to conduct noise monitoring to meet these new requirements. In addition, mine operators also requested monitoring for silica to determine silica quartz exposures.
The companies evaluated were all small employers, with one to seven quarry operations employees working in three types of open surface mines. The three types of mines included two basalt excavation mines, three portable crusher operations, and five sand and gravel operations. The primary difference in the three operations is the source, size, and type of rock handled. In basalt excavation, blasting and drilling is employed to break rock free of an open face; sand and gravel quarries dredge material from an open pit or pond; and portable crusher plants obtain material from near a road or pond to process for roadbed construction. In all three types of operations dump trucks, excavators, and frontend loaders are used to transport material. The rock is delivered to a processing area where the material is transported via conveyors through a series of crushers and screens for breaking and sorting. There are two types of crushers: cone and jaw. Jaw crushers break large rock into smaller sizes, while cone crushers are used to break aggregate into smaller aggregate. The crusher is run by a crusher operator who usually stays inside the operator's booth. In small operations, the operator would sometimes go outside to clear jams or for other equipment maintenance purposes. At larger operations there was also often a crusher mechanic and groundsman. The crusher mechanic worked outside near the crusher doing maintenance/repair tasks and frequently worked during breaks when there were no other noise sources nearby. The groundsman wa5 a laborer who cleared jams on conveyors, directed traffic and handled other labor requirements near the crusher.
In some cases, workers operated several pieces of equipment over the course of a shift.
Figme I : Portable screening and crusher operation
FRCG 01-10 page 1
Quarry operators reported that they control dust with water spray during dry weather conditions using water trucks or loaders to wet roadways. Some, but not all quarries had water spray systems to control dust during conveyor transport, at conveyor transitions, and during screening. Many of the samples gathered were collected during wet weather conditions and may not reflect dust/silica exposures during dry weather.
Figure 3: Truck loading from hopper
Figure 4: Crusher opemtor's booth at basalt excavation mine
Methods
Samples were collected between April2000 and March 2001 across all seasons. Quarry employees were monitored if they had potential for exposure to noise or silica dust. At three operations monitoring occurred on two separate days, while monitoring was done for one day at the other quarries.
Noise- Noise samples were collected using Quest 300 or Metrosonics 308 noise dosimeters. Dosimeters were set for slow response with two sets of measurement parameters: 1) a criterion level of 90 dB A, a threshold limit of 90 dBA, and an exchange
FRCG 01-10 page2
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rate of 5 dBA to measure MSHA PEL compliance, and 2) a criterion level of 90 dB A, a threshold limit of 80 dBA, and an exchange rate of 5 dBA for MSHA hearing protection program requirements. The microphone was clipped at the dominant hand shoulder. Measurement results using the first parameter set are compared to the MSHA PEL of 90dBA and results using the second parameter set are compared to 85 dBA, the hearing protection program level The maximum sound level is compared to 115 dBA. When measures exceed 115 dBA, engineering controls must be implemented to reduce exposure.
Silica- Full shift 1W A samples were collected from each worker using a Dorr-Oliver nylon cyclone at a flow rate of 1.7lpm Samplers were placed at the worker's lapel on the dominant hand side. Samples were collected on a pre-weighed PVC filter in a 2 stage cassette. Samples were analyzed gravimetrically by the FRCG lab for respirable dust then sent to the University of Washington Environmental Health Lab for percent quartz analysis. Field blanks were submitted with each sample set. The MSHA PEL is 10 mg/m3 /(% quartz + 2). The calculated quartz PEL is compared to the respirable dust concentration.
Results
The findings for noise and silica exposure are summarized in Table 1 by job type. For measurements using the PEL criterion, only groundsmen exceeded the PEL of 90 dB A, although crusher mechanics approached this limit with a mean of89.1 dBA. When exposures exceed the PEL, exposures must be reduced below 90 dBA, and Wltil exposures are reduced below that level hearing protectors are mandatory.
For all eight job types monitored, the mean 8-hour noise exposure was over the 85dBA hearing protection program level When that level is exceeded, hearing protection program requirements must be implemented including training, voluntary hearing testing, and provision of hearing protectors for voluntary use.
The allowable maximum sound level of 115 dBA was exceeded for two jobs: crusher operator and crusher mechanic. When this occurs, the job must be analyzed to determine if engineering controls are feasible for reducing the sound level.
For silica exposure, only groundsmen had a mean exposure at the silica PEL, with 3 samples at a mean of 100% of the MSHA PEL. In western Washington, where these companies are located, damp weather conditions can limit dust levels for much of the year. Many of these samples were collected under damp weather conditions. It is probable that higher exposures do occur during dry weather conditions frequently seen in summer months .
FRCG 01-10 page 3
a e . uarry xposure ssessmen or 01se an 1 ca . T bl 1 Q E A t fj N . dS.Ii Job Noise Hearing PEL Max Silica 0/oof
Samples Protection TWA Level Samples Silica (n) TWA (dBA) (dBA) (dBA) (n) PEL
Loader 12 86.7 83.4 112.2 15 36% Truck driver 4 89.4 84.0 112.4 5 22% Excavator 5 .86.1 81.3 113.2 4 15% Crusher operator 4 86.8 82.7 117.7. 3 17% Crusher mechanic 2 91.0 89.1 118.4 I 43% Grm.mdsman 3 92:6 95.3. 114.1 3 100% Dredger 2 86.4
.. 74.8 109.5 0 -Multiple machines 6 86.9 87.1 113.8 5 57% Other. 3 83.0 77.2 114.0 1 6% Total 41 86.7 83.6 114.2 37 38% . <·.·.-:·-:······ .. . "".:•': .-.. ~·.,··· .... IJil@jgl,l@.~~~.·~~·~JAA:d¥8~~ *weigh station operator, scraper operator, and rock wash operator
Noise and silica exposures are presented by quany type in Table 2. For basalt excavation and portable crusher plants, mean noise exposures' exceeded the hearing protection program level, indicating a need for a plant-wide hearing protection program. For sand and gravel operations, full shift exposures measured with the PEL and hearing protection criterion where below their associated limits, although the maximum sound level of 115 d.BA was exceeded for five of the seven jobs monitored.
FRCG 01-10 page4
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• • Table 2: Noise and Silica Exposures by Quarry Type
Quarry Type Loader Truck Excavator I Crusher Crusher Grounds-Driver Operator Mechanic man
Basalt Excavation - 2 operations NoiseN 3 1 3 1 HPtwa(dBA) 87.1 NM 89.4 93.2 PEL twa (dBA) 81.4 79.2. 82.7 92.6 MAX(dBA) 107.4 99.9 110.8 128.4 Silica N 4 2 3 1 % of Silica PEL 26% 6% 20% 19%
Portable Crusher Plant- 3 operations NoiseN 5 2 1 1 3 HPtwa(dBA) 93.3 NM 83.6 89.4 92.6 PEL twa (dBA) 90.9 84.8 74.3 86.4 95.3 MAX(dBA) 115.2 114.9 106.8 117.6 114.1 Silica N 6 1 0 0 3 % of Silica PEL 67% 77% - - 100%
Sand and Gravel - 5 QI>erations NoiseN 4 1 2 2 1 HPtwa(dBA) 83.1 89.4 82.8 85.2 92.6 PEL twa (dBA) 75.6 87.1 79.3 81.9 91.7 MAX(dBA) 111.9 117.8 116.8 117.8 119.2 Silica N 5 2 1 2 1 % of Silica PEL 5% 12% 2% 16% 43%
~1:':~ basalt ~~~vll~()J),; :rr:- ~~ll!~ ~~~rP!Il,Ilt; ~9: 88114 -~4. ~aye!; NM- not measured J:DIJilil$i4.~iQ~--.~:;~-;6Ve~;ljl•4'MS.~-••4&rc~
Dredger
1 92.1 89.7 112.8
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1 80.7 59.8 106.2
Multiple Machines
3 90.1 85.1 111.9
2 24%
2 NM 96.4 116.1
2 116%
1 80.7 74.7 115.1
1 4%
------------------------------FRCG01-10
• Other TOTAL
1 12 75.1 87.6 65.0 82.0 110.8 ll0.8
0 12 - 20%
1 16 88.5 90.4 84.0 89.9 110.5 114.3
1 13 6% 78%
1 13 85.6 84.4 82.6 78.5 120.8 ll5.2
0 12 - ll%
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Discussion and Recommendations
Noise- The revised MSHA noise standard was developed to protect miners' hearing, based on research indicating that hearing loss occurs with average sound levels below 90 dBA. The operations monitored in this study had average sound levels less than 90 dBA but over 85 dBA, the new level for required hearing protection programs. MSHA has developed resources to assist mine operations with compliance with the revised noise standards. These resources can be accessed at:http://www.msha.gov/1999noise/noise.htm.
When average sound levels exceed 90 dBA or when maximum sound levels exceed 115 dBA, feasible engineering controls must be implemented to reduce noise levels. Hearing protectors are not an acceptable alternative if feasible engineering controls are available.
Some examples of controls for open surface mining operations include:
Heavy Equipment • Fit heavy equipment with enclosed cabs and air conditioning. Ensure that doors and
windows are kept closed. • Ensure all equipment has exhaust muftlers and that exhaust pipes are directed away
from the operator's cab. Generator and Generator Trailer • Fit generator with supply and exhaust air muftlers. • Keep generator doors tightly closed. • The generator hood can be lined with sound dampening material. • If possible, keep the trailer closed. If that is not possible because of heat build up,
position the doors away from where quarry personnel are located. • Locate the trailer as far away as possible from personnel. Noise levels fall as the
distance increases from the generator. For example, if a smmd level at the generator is 120 dB, it will be 85 dB 50 feet away. ·
• Double hearing protection (plugs and muffs) should be worn if the trailer must be entered when the generator is operating. An alternative is to prohibit entry into the trailer when the generator is operating.
Conveyors • Upgrade or install conveyor belt brushes to clear soil from belts to reduce the need for
belt cleaning by the groundsman. Crushers • Sound proof and air condition the crusher operator's booth. Holes and cracks open to
the outside are the greatest source for noise transmission from outside. The booth can be lined with sound proofing or thick plywood to further reduce sound levels inside the booth.
• The operator should spend as much time as possible inside the booth with doors and windows closed.
Shakers • For rod decks, experiment with increasing the slot width during the wet season to
reduce the frequency of jams and need for manual cleaning. Covering this apparatus would keep the unit drier and may reduce binding.
FRCG 01-10 page6
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Other • Install silencers on compressed air wands. • Prohibit use of compressed air to clean clothes. • Shift the groundsman work schedule to reduce time near operating equipment (e.g. remove accumulated soil beneath conveyors pre- or post-shift) or use a mini-cat with enclosed cab to remove accumulated soil.
Silica - During our survey, dust and silica exposures were usually below the PEL, although overexposures did occur at two of the portable crusher operations. Since the majority of sampling occurred during wet weather, further sampling is recommended to assess exposure during dty weather .
FRCGOI-10 page7
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CROSS-SECTIONAL SURVEY OF NOISE EXPOSURE IN THE MINING INDUSTRY
Eric R. Bauer, Mining Engineer Jeffery L. Kohler, Laboratory Director
National Institute for Occupational Safety and Health Office of Mine Safety and Health Research
Pittsburgh Research Laboratory
ABSTRACT
Prolonged exposure to noise over a period of years generally causes peqnanent damage to the auditory nerve and/or its sensory components. This irreversible damage, known as noise· induced hearing loss (NlHL ), is the most common occupational disease in the United States today. Workers suffering from NIHL have difficulty understanding human speech and hearing other workplace cues. Despite the use of regulations and efforts by government and industry to reduce NIHL, the · problem today is as prevalent as it was more · than two decades ago. Recently, the Mine Safety and Health Administration (MSHA) promulgated a new regulation that is designed to reduce :r-miL in the mining industry. One of the more significant provisions is the elimination ofMSHA ·s past practice of giving "credit" for the use of personal hearing protection, thereby reestablishing the primacy of engineering and administrative controls.
However, there is a knowledge gap that is impeding. the development and implementation of engineering and administrative controls. Although significant data exist on the exposure to noise by occupational code, little is known about the noise sources that contribute the most to the worker's dose. This is problematic in a
workplace with multiple noise sources and workers who travel among noise sources. Yet without this knowledge, it is difficult to focus control efforts in any practical manner. Thus, it is important to characterize noise sources sufficiently well so that the sources moet hazardous to hearing are identified and those conditions of exposure that are most amenable to engineering controls are pinpointed a.~ well. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) is conducting a cross· sectional survey of noise sources and worker noise exposures in the mining industry to address this deficiency. The initial effort, conducted at a coal preparation plant and results are described in this paper. Preliminary analyses indicate that the noise levels on all floors exceeds 90 dBA in most areas, and that levels as high as 11 S. dB A were recorded. In addition, the one worlcer whose responsibility is to monitor the equipment and "house clean" the plant is slightly overexposed, even though he spends only half the shift in the plant General infotmation on the hearing loss problem in mining, a review of hearing protection use and noise regulations in mining, and other background materials are also presented.
INTRODUCTION
Noise is often regarded as a nuisance rather than as an occupational hazard. However, overexposure to noise can cause serious hearing loss. In 1996, NIOSH reported that occupational bearing loss is the most common occupational disease in the United States today, with 30 million workers exposed to excessive noise levels (NIOSH, 1996). The problem is particularly severe in all areas of mining (surface, processing plants, and underground), with studies indicating that 70% to 90% of miners have a Nilfl.. large enough to be
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-classified as a hearing disability (NIOSH, 1976; • Franks, 1996). This alanning prevalence of • hearing loss among miners is shown in Figw-e 1. For example, the median hearing threshold of retired miners was 20 decibels (dB) greater than that of the general population. By age 60, over I 70% of miners had a hearing loss of more than 25 dB, and abOut 25% had a hearing loss of more than 40 dB. Franks ( 1996) review of a private company's 20,022 audiograms indicated tbat the number of miners with hearing im.painnents increased exponentially with age until age SO, at which time 90% of the miners had a hearing impairment.
z LIJ :e 0:
Hearing loss greater than 25 dB
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~-CE <! L&J :t "'!!'" -!:: 3 (I') ~ LIJ z ~
0 20 30 40 50 6Q MINERS AGE
Figure 1: Hearing loss as a fundion of age (1\"'OSH, 1976).
Since the passage of the Federal Coal Mine Health and Safety Act of 1969, there has been some progress in controlling mining noise. Machinery manufacturers have incorporated
design changes to reduce noise levels. At the same time, however, many of these gains have been diminished by the use of ever larger, more powerful, and sometimes noisier machines.
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Thus, the number of miners overexposed to noise, as defined by federal regulations, still exceeds their overexposure to all oth~r health since the 1970s, although the percentage of miners overexposed to current MSHA noise regulations remains high (Seiler, et al. 1994). MSHA found that the percentage of coal miners with noise exposures exceeding federal regulations, and unadjusted for the wearing of hearing protection, was 26.5% and 21.6% for
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hazards. Data from more than 60,000 full-shift MSHA noise surveys show that the noise exposure of selected occupations has decreased surface and underground mining, respectively. Table I lists recently published data from MSHA noise surveys of exposures in the coal and metal/nonmetal mining industries (Federal Register, 1999). ·
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Table I - MSHA noise samples exceeding specified TW A11 sound levels.
90-dBA threshold 80-dBA threshold Industry TWAs sound segment level, dBA1 Number of Percent of Number of Percent of
samples samples samples samples
90 (PEL)2 1075 25.3 ---------- ------------Coal
85 (Action Level) ----------- ------- 3268 76.9
Metal/ 90 (PEL) 7360 17.4 ------~---- -----------Nonmetal 85 (Action Level) ------------ ------------ 28,250 66.9
1TWA8 is the sound level, if constant over 8 hours, would result in the same noise dose as measured. 2Pel-Pennissible exposure level
Despite the extensive work done in the 1970s and 1980s, NIHL is still a perva.-;ive problem. MSHA has published new Noise Health Standards for Mining (Federal Register, 1999). One of the changes will be the adoption of a provision similar to OSHA's Hearing ConseiVation Amendment. MSHA concluded in a recent survey that if an OSHA-like hearing conservation program (HCP) were adopted, hypothetically 78% of the coal miners surveyed would be required to be in a bearing conservation program (Seiler and Giardino, 1994). Based on full-shift time-resolved dosimeter measurements at six U.S.longwall operations, Bartholomae and Burks ( 1 995) found that all the longwall face wrukers surveyed in these mines w~uld be required to be
in a hearing conservation program. These data are corroborated by data collected in the National Occupational Health Survey of Mining · (NOHSM) during the 1980s (Greskevitch et al., 1996). Based on this survey, the projected mine workers potentially overexposed to noise was approximately 200,000 workers, or 73% of the workforce.
PERSONAL HEARING PROTECTION
At first glance, personal hearing protection devices ( eatplugs, eannuffs, etc.) seem to be a relatively cheap and simple solution to almost any noise problem. However, good industrial hygiene and safety practices suggest that hearing protectors should be considered onJy as
an interim or secondary noise control solution and that engineering and/or administrative controls should be first employed. There are several reasons for this. First, earplugs and eannuffs generally do not provide the same degree of protection in the mining workplace as they do in the laboratory or other types of workplaces (NIOSH, 1996; and Giardino and Durkt, 1996). The usc of personal hearing protection (PHP) was studied by Stewart and Burgi (1980) and Berger (1983), who found that earmuffs have serious limitations when worn under mine conditions. These include much less real work noise attenuation than that measured under laboratory conditjons and the possibility of reduced hearing causing a safety hazard (AIHA, 1986). The effectiveness ofPHP can be improved through proper fit, but the possible hazard from overprotection while wearing PHPs is unresolved.
Second, miners often refuse to wear hearing protectors because they are uncomfortable, annoying, or prevent them from perceiving signals such as the sounds that precede a roof fall ("roof talk") or backup alarms on moving equipment (NIOSH, 1996). Often miners simply do not appreciate the risk presented by excessive noise, nor do they believe that using PHPs will protect them.
Finally, spot surveys have shown that miners believe that they are wearing hearing protectors more than they really are. For example, a research group in New South Wales, Australia, surveyed one mine where 75% of the miners stated that they used hearing protectors "regularly" (55%) or .. all the time" (20%). In fact, the investigators found that only 40% of · the miners wore hearing protectors regularly and 20% wore them some of the time (O'Malley and O'Beirne, 1993).
The limitations of PHPs underscore the importance of using engineering and administrative controls to the fullest extent practicable. At the same time, however, PHPs can offer some reasonable measure of protection, especially when fit and worn
correctly. As such, their importance in an "' overall hearing loss prevention program should l not be underestimated. J1
HIGHLIGHTS OF NOISE REGULATION: INMINING I
Regulation of noise in mining is covered m Title 30 of tile Code ofFederal Regulations (30 CFR). The Federal Coal Mine Health arid Safety Act of 1969 established requirements for protecting coal miners from excessive noise and, subsequently, the Federal Mine Safety and Health Act of 1977 broadened the scope to include all miners, regardless of mineral type ( CFR 30 1977). The regulations allowed a pennissible exposure level PEL) of 90 dB A TWA over 8 hours (TW J\s). Exposure below the criterion of90 dBA is unregulated, while continuous exposure to levels greater than 115 dBA is not permitted. Many noise sources are not continuous, and movement by the worker generally results in exposure to various levels of noise for differing periods of time. This problem of exposure versus duration of exposure is evaluated using the well-known noise exposure index (NEI); the worker is out o compliance if the NEI exceeds unity. In practice, the dose received is most often detennined using a type 2 personal noise dosimeter, as defined by American National Standards Institute (ANSI) SI.25-l99l(Rl997) American National Standard for Personal Noise Dosimeters (ANSI, 1991). Despite allegations that personal noise dosimeters are not as accurate as sound level meters or that they read erroneously with impulse noises, research has found that they are as accurate as sound level meters (Valoski etal., 1995); moreover, they correctly weigh impulse levels (Evans et al., 1991).
The new rulemaking efforts undertaken by MSHA, adopted in September 1999 and scheduled to go into effect in September 2000, retain the PEL of 90 dB A TWAs, and include a new action level which is a noise dose of 50%, or equivalently a TWAs of 85dBA. The new regulation requires the mine operator to enroll a
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miner in an HCP if, during any work shift, the miner's noise exposure equals or exceeds the action level. Moreover, the new rules establishes the primacy of engineering and administrative noise controls, and explicitly eliminates credit for the usc of personal hearing
protection. Additional criteria include, a dual hearing protection level of 105 dBA TWA8, and no miner is permitted to be exposed to sound levels exceeding 115 dBA. Specific details of the new regulations are listed in Table II.
Table ll - Details of Part 62 - Occupational noise exposure measurements.
TWAs, Sound levels
Exchange Type
dB A Dose integrated,
rate, dB Weighting Response
dB A
Action level 85 50% . 80to 130
Pennissible 90 100% 90to 140
exposure level
CROSS-SECTIONAL SURVEY OF NOISE EXPOSURE
Methods
NIOSH is conducting a study to obtain multi-shift worker noise exposure and equipment noise levels to develop an up-to-date comprehensive profile of miners' noise exposures as a function of equipment and activity-specific measures. This study is a crucial component in the effort to develop noise controls because it will define the sources of miners' dosages and the characteristics of those sources. Once this infonnation is available,
5 A Slow
5 A Slow
efforts can focus on the development and application of appropriate engineering and administrative control measures that will result in reduced exposures for mine workers. Data collection will be perfonned at underground and surface coal and metaVnonmetal mines and in mineral processing plants. Although an exact study population has not been defmed at this time, it is necessary to survey all segments of the mining industry because workers across the . industry continue to have a significant risk of hearing impairment, as iJlustrated by the MSHA inspector noise survey data published in the Federal Register (1999) (see Table III).
- • i Table III - MSHA inspector noise samples exceeding specified TWAs sound levels.
90-dBA 80-dBA threshold threshold
Mining Number
Occupation of Percent of sector Percent of
samples samples>90 samples $85
dBA(PEL) dBA (action level)
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Front-End-Loader Oper ........................... 12,812 12.9 67.7 Truck Driver ............................................ 6,216 13.1 73.7 Crusher Oper ........................................... 5,357 19.9 65.1 Bulldozer Oper ........................................ 1,440 50.7 86.2 Bagger ..................................................... 1,308 10.2 65.0 Sizing!W ashing Plant Oper.. ................... 1,246 13.2 59.7 Dredge/Barge Attendant. ......................... 1,124 27.2 , 78.7 Clean-up Person ...................................... 927 19.3 71.3
Metal/ Dry Screen Oper ...................................... 871 11.7 57.6 Nonmetal Utility Worker ......................................... 846 12.4 60.6
Mechanic ................................................. 761 3.8 43.9 Supervisors/ Administrators ..................... 730 9.0 32.2 Laborer .................................................... 642 17.1 65.7 Dragline Oper. ......................................... 583 34.0 82.5 Backhoe Oper .......................................... 546 8.4 52.6 • Dryer/Kiln Oper ...................................... 517 10.5 55.5 Rotary Drill Oper. (electric/hydraulic) .... 543 39.6 83.1 Rotary Drill Oper. (Pneumatic) ............... 489 64.4 89.0
Continuous Miner Helper ....................... 68 33.8 88.2 Continuous Miner Oper .......................... 262 . 49.6 96.2 Roof Bolter Oper. (Single) ..................... 234 21.8 85.5 Roof Bolter Oper. (Twin) ....................... 92 31.5 98.9 Shuttle Car Oper ..................................... 260 13.5 78.5 Scoop Car oper. ....................................... 94 18.1 74.5 Cutting Machine Oper ............................. 22 36.4 63.6
Coal Headgate Oper ......................................... 20 40.0 100.0 Longwall Oper ........................................ 34 70.6 100.0 Jack Setter (Longwall) ............................ 25 23.0 68.0 Cleaning Plant Oper ................................ 107 36.4 77.6 Bulldozer oper ......................................... 225 48.9 94.2 Front-End-Loader Oper ........................... 244 16.0 76.6 High wall Drill Oper. ............................... 83 21.7 77.1 Refuse/Backfill Truck Driver .................. 162 13.6 78.4 Coal Truck Driver ................................... 28 17.9 64.3
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The plan of research is comprehensive and is designed to include all workers at each site investigated. The data collected wilJ include worker noise dose, equipment noise, and other worker, mine, and equipment-specific infonnation necessary for characterizing the noise sources. At each site, mine workers will wear time-resolved dosimeters. During the shift, a task-based exposure assessment methods (T-Beam) approach studies will be used to correlate each mine worker's tasks, the noise dose received, and the noise. source responsible for that incremental contribution to the miner's total exposure. Noise profiling of mine machinery will be conducted using hand-held sound level meters. This will consist of AWeighted Equivalent Continuous Sound Levels
(Leq) measurements on a unifonn grid pattern to develop detailed noise contours and "area sweeping" of mine machinery to calculate sound power. The instruments that will be used to make these measurements include Quest Technologies Model Q 400, Noise Dosimeters, and Quest Model2900,Integrating and Logging Sound Level Meters (fig. 2). Finally, sitespecific parameters, such as characteristics of the mine plan, wilJ be documented to support subsequent analyses. The bulk of the data collection activities are completed over five shifts. Typically, one or two site visits are made in advance of the data collection to gather infonnation for the design of the site~specific data-collection activities.
Figure 2: Dosimeter and sound level meter for conducting noise surveys.
Results
Progress to date includes completion of pilot studies at an underground coal mine and underground limestone mine, and a full-scale study conducted at a coal preparation plant. The pilot studies served both as training exercises for the field crews and for refming the data collection and analysis procedures. The study at the preparation plant included surveying the noise on all eight floors and a contr9l room (fig. 3). The data collected included A-Weighted Leq , as well as Linear 113rd Octave Band Sound Pressure Levels (SPL' s) arourid all major pieces of processing equipment.
The plant was a modem!multicircuit coal preparation plant. It was constructed of steel Ibeams for internal support with corrugated steel. walls (fig. 4); except for the first floor, which had walls constructed from concrete block. All floors were constructed of 4 inches ·of concrete, except on the second and sixth floors, which were made of open steel grating. In addition, there were many open spaces that extended from one floor to the next, or in some cases, from the ground floor to the top floor. The proce.'ISing equipment included classifying cycJones, sieve bends, magnetic separators, flotation cells, banana screens, heavy media cyclones, D&R screens, coal spirals, centrifuges, clean coal and refuse conveyors, and pumps .
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Figure 3: Noise measurement being made with a sound level meter.
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Figure4:
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The measured Leq levels ranged from 83 to 115 d.BA, with most floors averaging in the upper 80s and above (see Table IV). Although Table N lists the dominant noise sources,
· characterization of noise sources in the plant was a complicated task for several reasons. First, the sheer number of pieces of equipment and their close proximity to each other made separating specific noise sources extremely difficult, and process considerations made it impossible to operate equipment independently. Next, the openness of the building allowed noise to propagate between floors, as did the floor-tofloor connections of the equipment. Finally, the
measured noise carne from several sources, most often a combination of airborne and structure-borne noise paths (fig. 5). Airborne noise was present as direct sound, generated by the equipment, the proces~, and motors, and as reverberant sound reflected by the building's walls and floors. Structure-borne noise paths resulted from equipment vibration and transfer of that vibration to the building's structural components. The vibrant energy was then radiated as airborne sound into the surrounding area. An example of a contour plot of the noise levels is illustrated in Figure 6.
' Table IV- Summary ofLeq levels.
Floor Leq Range, Major equipment Dominant noise source (Leq, dA)
dB A
1 91-99 pumps, pump motors classifying cyclone pump (99.4 d.BA)
2 92-96 Conveyors clean coal and refuse conveyors (93.5 dB A)
3 93- 103 dewatering screens, centrifuges, fine refuse dewatering screen (101.6 mag separators, dB A)
4 94- 101 sieve bends, D&R screens, coal clean coal and refuse D&R screens spirals (100.4 dBA)
heavy media cyclones, banana s 91 - 101 screens, flotation cells, sieve raw coal banana screens (99.8 dBA)
bend
6 89- 115 sieve bends, cyclones fme clean coal sieve bends (104.6 d.BA)
7 89-92 raw coal conveyor, sieve bends,
None mag separator
8 88-91 Cyclones 15-inch dia Classifying cyclones (91 dBA)
Control 74 (Inside) plant controls, monitors, etc. None Room 90 (Outside)
~ \.J
··-··-··~
Key -.t..- Airborne
S - Struclureborne
Figure 5:
Source
•••••••••
-··-··
•• • • •,.. r Reterberant •. ., • • •• •• • • •• •• • • • •• •• • ~ .. .. -· .. .. . .. .
~A. Direct
• i i . . I Vs
Example of airborne (A) and structureborne (S) noise paths.
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-~:·.C·At ~F~F,;,: rJI .... ~.\ ·;· SOUNf,: r.::-=i f.~"::SUP.E LE'/t:.,. rLOC·R.;
Figure 6: Example of noise contours in prep plant •
A.few general observations of the noise levels on all floors can be made. (I) Although the highest noise levels were recorded on floor 6, floors 3 and 4 are considered to be the noisiest floors overall because the noise was consistent throughout the entire floors. (2) Vibration is certainly a factor in generation of noise throughout the plant. (3) Reverberant noise from the building walls is likely a significant component of the noise throughout the plant. (4) The openness and construction of the plant is conducive to noise propagation between floors. This likely resulted in "smearing" or "blending" of the noise from floor to floor.
In addition, several man-shifts were spent following the Plant Controls Man, documenting his work activities while he wore a personal dosimeter. He wore a personal dosimeter for parts of two shifts (8 a.m. to 3 p.m.), while a NIOSH Researcher perfonned a time and
motion study as he traveled throughout the plant Table V summarizes the Plant Control Man's location throughout the shifts. Table VI presents the projected dose and time-weighted average. The projected dose, in percent, is computed by measuring the dose for a specified time period (in this case, approximately 7 hrs) and extrapolating it to a different time period (8 hrs). The time-weighted average is the average soWld level computed over an 8-hour time period.
Figure 7 is a plot of the cumulative dose for the measurement period. The sections of the graph with the steepest slope indicate the periods that the Plant Controls Man was in the plant and receiving most of his measured noise dosage. · In contrast, the flat slope sections of the graph arc the minimal dosages accumulated while he was in the control room or traveling between the control room and plant.
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Table V - Location of Plant Controls Man
Location Duration, Time, Percent . pet. Dose miD.
Control Room 210.20 51 li Plant 189.25 46 88
Traveling between plant and 11.50 3 ND2 control room
Total 411 100 100
1 Although no control room was under 80 d.BA, some higher noise levels occurred because of equipment and the door being opened.
2ND -Not determined. Since time period was small and because the old plant was not running, the dose is included in the Control Room dose
Table VI- Projected 8-Hour Dose for Plant Controls Man (one shift)
MSHA Projected Dose, pet Time Weighted Average (TWA8), dBA Designation
Action Level 159.96 93.4
Permissible Exposure 152.36 93.0
Level
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CUMULil.TIVE DOSAGE· PLANT CONTROLS MAN
150 -··-------------·
140i
1JC ~ 120.!
I
1!0 ~ -·-······~ ........ _,_ __ ...... , .. , .. ---
·-.:s .. ·· ...
~ 1.11 0 < (/)
0 0
100 ~ so .1
I
eo i 70 i 60~
! so~ : 40..;
30 ~ 2.0 ·l 10 -1
0 ~
···· .......
IN CONTROL f!OOM
- 90 dB cri.le.rion, 80 dB lhresl'lold 90d6cril~on, 90 dSII!teshold
0 2 3 4 5 7
TIME (liOU~S}
Figure 7: Plot of cumulative noise dose for plant controls man.
SUMMARY
Noise-induced hearing loss is a concern in the mining industry. One study revealed that more than of 90% of miners have a hearing impainnent by the age of 50 (Franks, 1996). In addition, based on thousands of inspector noise samples, MSHA has suggested that miners in all sectors of mining and occupations continue to have a significant risk of NIIIL over a working lifetime. Despite government and industry efforts over the past three decades, hearing loss remains relatively unchanged in the industry. It is apparent that it is a complex problem that will require an understanding of its underlying causes. Although engineering and administrative controls retJresent the desired
means of protecting workers from excess exposure, it wj)J be necessary to understand where mine workers receive their exposure and the specific characteristics (frequency, duration,' level) of the offending noise sources. The NIOSH cross-sectional swvey proj~t wiJl establish valid worker noise exposure and equipment noise level data for fonnulating intervention strategies that target high-risk equipment and activities with the noisiest exposures for mine workers.
The coal preparation plant study highlighted in this paper illustrates the na~ of the study and the complexities of the data analysis. The ultimate value and application of the findings from this plant will be in
aggregated fonn when it can be examined as part of a larger sample of plants and mines. However, there is specific value to these findings as well. Careful study and review of the contour plots revealed "hot spots" of higher noise levels. These can be the starting points for applying engineering and administrative controls in an attempt to reduce noise and worker exposures.
REFERENCES
AIHA, American Industrial Hygiene Association [1986]. "Noise & Hearing Conservation Manual." Fourth Edition, (Chapter 10: Responding to Warnings And Indicator Sounds), edited by_ Berger:, E.H., W.D. Ward, J.C. Morrill and L.H. Royster, p 368.
ANSI [1991]. American National Standard Specification for Personal Noise Dosimeters. Sl.25-1991 (R1997).
Bartholomae, R.C., and J.A. Burks [1995]. OccupationaJ Noise Exposures in Underground Coal Mines. Proceedings of Inter-Noise 95, Newport Beach, CA, July 10-12, pp. 833-836.
Berger, E.H. [1983]. Using the NRR to estimate the real-world perfonnance of hearing protectors. Sound and Vibration, Jan, pp. I 2-18.
30 CFR [ 1997]. Code ofF ederal Regulations (CFR) governing noise exposure in mining. CFR 30, Subchapter 0, Part 70, Subpart F: Noise Standards for Underground Coal Mines; Subchapter 0, Pa!l 71, Subpart D: Noise Standards for Surface Work Areas of Underground Coal Mines and Surface Coal Mines; Subchapter 0, Part 55, Section 55.5: Metal and Nonmetal Open Pit Mines; Section 56.5: Sand, Gravel, and Crushed Stone Operations and 57.5: Metal and Nonmetal Underground Mines.
Federal Register [1999]. Health Standards for Occupational Noise Exposure; Final Rule. Department of Labor, Mine Safety
and Health Administration, 30 CFR Parts 56 an1 __ 57 et al., Vol. 64, No. 176, September 13, pp. -49548-49634. •
Franks, J.R. [1996]. Analysis of audiograms for a large cohort of noise-exposed I miners. lnternal Report, National Institute for Occupational Safety and Health, Cincinnati, OH, pp. 3-8.
Giardino, D.A., and G. Durkt, Jr. (1996]. Evaluation ofMuffType Hearing Protectors as Used in a Working Environment AlliA Journal, 2.57 No. 3, March.
Greskevitch, M.K.. et al. [ 1996). "Results from the National Occupational Health Survey of Mining (NOHSM)." .QHHS (NIOSH) Publication No. 96-136, September, pp. 17-18.
NIOSH [1996]. National Occupational Research Agenda (NORA). National Institute for Occupational Safety and Health, Publication No. 96-115, p. 14.
NIOSH [1976]. Survey of Hearing Loss in the Coal Mining Industry. National Institute fo: Occupational Safety and Health, Publication No. 76-172, June, 70 pp.
O'Malley, A., and T. O'Beime [1993]. Managing Noise Emissions and Exposures in Underground Coal Mines. Australian Coal
·Association Research Program End of Grant Report, NERDD&DP No. 1628, Worksafe Australia No. 911948, Riverview QLD 4303, Australia, September, 97 pp.
Seiler, J.P., M.P. Valoski, and M.A. Crivru [1994). Noise Exposure in U.S. Coal Mines. U.S. Dept. of Labor, Mine Safety and Health Administration, Informational Report IR 1214, 46pp.
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Seiler, J.P., and D.A. Giardino [ 1994]. The Effect of Threshold on Noise Dosimeter Measurements and Interpretation of Their Results. U.S. Dept. of Labor, Mine Safety and Health Administration, Informational Report IR 1224, 16pp.
Stewart, K.C., and E.J. Burgi [1980]. Noise-attenuating properties of eannuffs worn by miners. Final Report, VoL 1 on BOM Contract J0188018, NTIS PB 83-257063,46 pp.
Valoski, M.P., J.P. Seiler, M.A. Crivaro, and G. Durkt [1995]. Comparison of noise exposure measurements conducted with sourid level meters and noise dosimeters under field conditions. MSHA Report, 26 pp .