The Mine Safety and Health Administration (MSHA) is proposing to revise its existing health standards for occupational exposure to noise at metal, nonmetal, and coal mines. Section 101 of the Federal Mine Safety and Health Act of 1977 provides the authority for this rulemaking. The proposed rule provides increased health protection for miners by clarifying compliance requirements, including new requirements to address identified hazards, eliminating outdated and unnecessary standards, including more performance-oriented requirements, upgrading existing provisions consistent with advances in technology, and providing alternative methods of compliance where possible.

In this analysis, MSHA compared the costs associated with the proposed and the existing requirements. MSHA determined that the proposed rule would not result in major cost increases nor have an effect of $100 million or more on the economy.

This proposed rule would result in both increased costs and benefits. The total cost for compliance with the proposed rule is approximately $8.3 million. Costs to the metal/nonmetal industry would rise by about $8.0 million annually. The proposed rule would result in net cost increase of less than $0.3 million for the coal industry. This amount would result from the significant savings due to the elimination of current coal industry requirements for performing and recording semiannual noise surveys and other related surveys and reports; the Agency estimates that these surveys and reports cost $5.3 million annually. The most costly provision of the proposal would require audiometric testing for miners who are exposed to noise in excess of the PEL; this provision would cost approximately $3.6 million. The second most costly provision which addresses engineering controls represents an additional $3.5 million annually.

The benefits would be the reduction in the numbers of cases of noise induced hearing loss (NIHL) and hearing impairment. MSHA expects that implementation of the provisions in the proposed rule would reduce the number of cases of noise-induced hearing impairment by about 67%. Full compliance with the proposed rule would likely prevent or contribute to the prevention of 30,600 cases of hearing impairment over 40 years (approximately 760 cases of hearing impairment per year). MSHA also expects reductions in the number of worker's compensation claims for hearing loss, workplace injuries, absenteeism, and physiological and psychological problems that are associated with NIHL.

The proposal would decrease the current paperwork burden (about 15,000 fewer hours required). Coal mines would use about 89,000 fewer hours, but metal/nonmetal mines would use 74,000 more hours.

SUMMARY

Introduction

The industry profile provides background information describing the structure and economic characteristics of the mining industry. This profile provides data on the number of mines, their size, the number of employees in each segment, as well as selected market characteristics.

Overall Structure of the Mining Industry

MSHA divides the mining industry into two major segments based on commodity, the coal mining industry and the metal and nonmetal (metal/nonmetal) mining industry. These major industry segments are further divided based on type of operation (underground mines, surface mines, and independent mills, plants, shops, and yards). MSHA maintains its own data on mine type, size, and employment. MSHA also collects data on the number of contractors and contractor employees by major industry segment.

MSHA categorizes mines as to size based on employment. For the purpose of this Preliminary Impact Analysis and Initial Regulatory Flexibility Analysis (IRFA), MSHA defines small mines to be those having fewer than 20 employees and large mines to be those having at least 20 employees. Over the past 20 years, for rulemaking purposes, MSHA has consistently used this small mine definition. As will be discussed in the various sections of the preamble, MSHA's IRFA meets the requirements of the Regulatory Flexibility Act particularly as it covers small businesses. Table II-1 presents the number of small and large mines and the corresponding number of miners, excluding contractors, by major industry segment and mine type. Although MSHA does not maintain a data base of the numbers of miners by job title, Table II-2 presents an estimate of the numbers of miners by job title groups based in part on research conducted by the U.S. Department of the Interior, former Bureau of Mines. MSHA does not maintain a data base which would allow determination of the types of services provided by independent contractors or the job titles of contractor employees. Table II-3, however, presents MSHA data on the numbers of independent contractors and the corresponding numbers of employees by major industry segment and the size of the operation based on employment.

Source: U.S. Department of Labor, Mine Safety and Health Administration, Office of Standards, Regulations, and Variances, based on preliminary 1995 MIS data (quarter 1 - quarter 4, 1995). MSHA estimates assume that office workers are distributed between large and small operations the same as non-office workers.

** Continuous miner and longwall operators at metal/nonmetal mines are included in the job group "laborer-miner-utility man."

Extrapolated from U.S. Bureau of Mines, Characterization of the 1986 Coal Mining Workforce (IC 9192) and Characterization of the 1986 Metal and Nonmetal Mining Workforce (IC 9193), 1988.

Source: U.S. Department of Labor, Mine Safety and Health Administration, Office of Standards, Regulations, and Variances, based on preliminary 1995 MIS data (quarter 1 - quarter 4, 1995). MSHA estimates assume that office workers are distributed between large and small contractors the same as non-office workers.

Economic Characteristics

The U.S. mining industry's 1995 production is worth in excess of $58 billion in raw mineral resources. Coal mining contributed about $20 billion to the Gross Domestic Product in 1995 and metal/nonmetal mining contributed about $38 billion ¹. Another $17billion is reclaimed annually from recycled metal and mineral materials such as scrap iron, aluminum, and glass².

The Agency obtained financial information on the various mineral commodities primarily from the U.S. Department of the Interior, former Bureau of Mines, and the U.S. Department of Energy, Energy Information Administration.

STRUCTURE OF THE COAL MINING INDUSTRY

MSHA separates the U.S. coal mining industry into two major commodity groups, bituminous and anthracite. The bituminous group includes the mining of subbituminous coal and lignite. Bituminous operations represent over 93% of the coal mining operations, employ over 98% of the coal miners, and account for over 99% of the coal production. About 60% of the bituminous operations are large; whereas, about 90% of the anthracite operations are small.

Underground bituminous mines are more mechanized than anthracite mines in that most, if not all, underground anthracite mines still hand-load. Over 70% of the underground bituminous mines use continuous mining and longwall mining methods. The remaining use drills, cutters, and scoops. Although underground coal mines generally use electrical equipment, a growing number of underground coal mines use diesel haulage equipment.

Surface mining methods include drilling, blasting, and hauling and are similar for all commodity types. Most surface mines use front-end loaders, bulldozers, shovels, or trucks for coal haulage. A few still use rail haulage. Although some coal may be crushed to facilitate cleaning or mixing, coal processing usually involves cleaning, sizing, and grading.

Preliminary data for 1995³ indicate that there are about 2900 active coal mines of which 1,760 are small mines (about 61% of the total) and 1,130 are large mines (about 39% of the total).

These data⁴ indicate employment at coal mines to be about 103,200 of which about 13,400 (13% of the total) worked at small mines and 89,700 (87% of the total) worked at large mines. MSHA estimates that the average employment is 8 miners at small coal mines and 79 miners at large coal mines.

STRUCTURE OF THE METAL/NONMETAL MINING INDUSTRY

The metal/nonmetal mining industry consists of about 70 different commodities including metals, industrial minerals, stone, and sand and gravel. Preliminary data for 1995⁵ indicate that there are about 10,820 active metal/nonmetal mines of which 9,270 are small mines (about 86% of the total) and 1,550 are large mines (about 14% of the total).

These data⁶ indicate employment at metal/nonmetal mines to be about 194,600 of which about 61,100 (31% of the total) worked at small mines and 133,500 (69% of the total) worked at large mines. MSHA estimates that the average employment is 7 miners at small metal/nonmetal mines and 86 miners at large metal/nonmetal mines. Table II-4 presents the number of metal/nonmetal mines and miners by major commodity category, mine size, and employment. In addition, MSHA estimates that about 350 sand and gravel or stone operations are owned by state, county, or city governments.

* Includes office workers. Excludes contractors.

Metal Mining

Metal mining in the U.S. consists of about 25 different commodities. Most metal commodities include only one or two mining operations. Metal mining operations represent about 3% of the metal/nonmetal mines, employ about 24% of the metal/nonmetal miners, and account for about 35% of the value of metal/nonmetal minerals produced in the U.S.⁷ About 48% of the metal mining operations are small.

Underground metal mining uses a few basic mining methods, such as stope, room and pillar, and block caving with primary noise sources being diesel haulage equipment, pneumatic drills, and mills. Larger underground metal mines use more hydraulic drills and track-mounted haulage; whereas, smaller underground metal mines use more hand-held pneumatic drills. Stope mining uses more hand-held equipment. Surface metal mines include some of the largest mines in the world. Surface mining methods (drill, blast, haul) use the largest equipment and are similar for all commodity types.

Nonmetal Mining

For enforcement and statistical purposes, MSHA separates stone and sand and gravel mining from other nonmetal mining. There are about 35 different nonmetal commodities, not including stone or sand and gravel. About half of the nonmetal commodities include fewer than 10 mining operations; some include only one or two mining operations. Nonmetal mining operations represent about 7% of the metal/nonmetal mines, employ about 15% of the metal/nonmetal miners, and account for about 34% of the value of metal/nonmetal minerals produced in the U.S.⁸ About 70% of the nonmetal mining operations are small.

Nonmetal mining uses a wide variety of underground mining methods. For example, potash mines use continuous miners similar to coal mining; oil shale uses in-situ retorting; and gilsonite uses hand-held pneumatic chippers. Some nonmetal commodities use kilns and dryers in ore processing. Others use crushers and mills similar to metal mining. Underground nonmetal mining operations generally use more block caving, room and pillar, and retreat mining methods; less hand-held equipment; and more electrical equipment than metal mining operations. As with underground mining, surface mining methods vary more than for other commodity groups. In addition to drilling, blasting, and hauling, surface nonmetal mining methods include other types of mining methods, such as evaporation beds and dredging.

Stone Mining

There are basically only eight different stone commodities of which seven are further classified as either dimension stone or crushed and broken stone. Stone mining operations represent about 33% of the metal/nonmetal mines, employ about 39% of the metal/nonmetal miners, and account for about 19% of the value of metal/nonmetal minerals produced in the U.S.⁹ About 75% of the stone mining operations are small.

Stone generally is mined from quarries using only a few different methods and diesel haulage to transfer the ore from the quarry to the mill. Crushed stone mines typically drill and blast; whereas, dimension stone mines typically use channel burners, drills, or wire saws. Milling typically includes jaw crushers, vibratory crushers, and vibratory sizing screens.

Sand and Gravel Mining

Based on the number of mines, sand and gravel mining represents the single largest commodity group in the U.S. mining industry. About 57% of the metal/nonmetal mines are sand and gravel operations. They employ about 22% of the metal/nonmetal miners and account for about 11% of the value of metal/nonmetal minerals produced in the U.S.¹⁰ Over 96% of the sand and gravel operations are small.

Construction sand and gravel is generally gathered from surface deposits using dredges or draglines and only washing and screening milling methods. As in other surface mining operations, sand and gravel uses diesel haulage equipment, such as front-end loaders, trucks, and bulldozers. In addition, industrial sand and silica flour operations mill the ore using crushers, ball mills, screens, and classifiers.

ECONOMIC CHARACTERISTICS OF THE COAL MINING INDUSTRY

The U.S. Department of Energy, Energy Information Administration, reported that the U.S. coal industry produced a record 1.03 billion tons of coal in 1995 with a value of about $20 billion. Of the several different types of coal commodities, bituminous and subbituminous coal account for 91% of all coal production (940 million tons). The remainder of U.S. coal production is lignite (86 million tons) and anthracite (4 million tons). Although anthracite offers superior burning qualities, it contributes only a small and diminishing share of total coal production. Less than 0.4% of U.S. coal production in 1995 was anthracite¹¹.

Mines east of the Mississippi account for about 53% of the current U.S. coal production. For the period 1949 through 1995, coal production east of the Mississippi River fluctuated relatively little from a low of 395 million tons in 1954 to 630 million tons in 1990. (It was 568 million tons in 1994.) During this same period, however, coal production west of the Mississippi increased each year from a low of 20 million tons in 1959 to a record 490 million tons in 1995¹². The growth in western coal is due in part to environmental concerns that led to increased demand for low-sulfur coal, which is concentrated in the West. In addition, surface mining, with its higher average productivity, is much more prevalent in the West.

Preliminary MSHA data for 1995¹³ indicate that small mines produced about 4% of the total coal mine production (about 44 million tons) and large mines produced about 96% of the total (983 million tons). MSHA calculations indicate that the average total production per miner for 1995 was about 3,500 tons at small mines and 11,400 tons at large mines. The average total coal production for 1995 was about 25,000 tons per small mine and 867,000 tons per large mine.

The 1995 estimate of the average value of coal at the point of production is about $19 per ton¹⁴ for bituminous coal and lignite, and $36 per ton for anthracite. MSHA chose to use $19 per ton as the value for all coal production because anthracite contributes such a small amount to total production that the higher value per ton of anthracite does not greatly impact the total value. The total value of coal production in 1995 was about $20 billion of which about $0.9 billion was produced by small mines and $19.1 billion was produced by large mines. On a per mine basis, the average coal production was valued at $0.5 million per small mine and $17 million per large mine.

Coal is used for several purposes including the production of electricity. The predominant consumer of coal is the U.S. electric utility industry which used 829 million tons of coal in 1995 or 80% of the coal produced. Other coal consumers include coke plants (33 million tons), residential and commercial consumption (6 million tons), and miscellaneous other industrial uses (73 million tons). This last category includes the use of coal products in the manufacturing of other products, such as plastics, dyes, drugs, explosives, solvents, refrigerants, and fertilizers¹⁵.

The current rate of U.S. coal production exceeds U.S. consumption by roughly 90 million tons annually. In 1995, 89 million tons of this excess production was exported and the remainder was stockpiled. Japan (11.8 million tons), Canada (9.4 million tons), and Italy (9.1 million tons) were the top three importers of U.S. coal. Year-to-year fluctuations in exports of U.S. coal vary more than domestic consumption. During the 1990's, changes in exports from the previous year varied from a 24% increase to a 27% decrease; whereas, changes in domestic consumption only varied from a 4% increase to a 1% decrease¹⁶.

The U.S. coal industry enjoys a fairly constant domestic demand. Its demand by electric utilities continues to increase annually. MSHA does not expect a substantial change in coal demand by utilities in the near future because of the high conversion costs of changing a fuel source in the electric utility industry. Energy experts predict that coal will continue to be the dominant fuel source of choice for power plants built in the future. Nuclear and hydropower currently comprise, and are anticipated in the future to comprise, a small fraction of fuel sources for utilities.

The international market for coal was marked by several notable events in the 1990's. The breakup of the Soviet Union (USSR), a new political regime in South Africa, and economic policy changes in the United Kingdom and Germany contributed to price and demand changes in coal's global marketplace; newly independent, former USSR republics provided competition to U.S. companies for a share of the European coal market; and the deep European recession of 1993-1994 caused exports of coal to decrease¹⁷. Similarly, the cessation of the economic boycott of South Africa, and its new political leadership, has led to new interest in South African exports. South Africa ranks third after Australia and the U.S. in coal exports. Its coal exploration and mining have the nation poised to maintain its global position. The privatization of British power companies and the elimination of coal subsidies in Germany have led to an increased interest in U.S. coal. These international economic policy changes are predicted to create a substantial export opportunity for U.S. coal over the long term¹⁸.

The net effect of these aforementioned international activities appears to be a continued demand for U.S. coal at or near current level. The U.S. can expect additional competition, however, from other current coal producing countries (e.g., Australia, South Africa, former USSR republics, Poland), as well as from new suppliers in Colombia, Venezuela, China, and Indonesia¹⁹. The U.S. coal industry has vast reserves of unmined coal which is predicted to sustain coal's demand for another half millennium if mined at the current rate.

The economic health of the coal industry may be summarized as a fairly stable market which may be subject to periodic price and demand fluctuations. These fluctuations are largely functions of domestic supply disruptions and increased international competition. The 1993 average profit as a percent of revenue for the coal mining industry was about 3-4% after taxes²⁰.

ECONOMIC CHARACTERISTICS OF THE METAL/NONMETAL MINING INDUSTRY

Summary

The 1995 value of all metal/nonmetal mining output is about $38 billion²¹. Metal mining contributes $13.2 billion to this total and includes metals such as aluminum, copper, gold, and iron. Nonmetal mining is valued at $12.9 billion and includes commodities such as cement, clay, and salt. Stone mining contributes about $7.2 billion and sand and gravel contributes about $4.3 billion to this total.

The entire metal/nonmetal mining industry is markedly diverse not only in terms of the breadth of minerals, but also in terms of each commodity's usage. For example, metals such as iron and aluminum are used to produce vehicles and other heavy duty equipment, as well as consumer goods such as household equipment and soda pop cans. Other metals, such as uranium and titanium, have limited uses. Nonmetals like cement are used in construction while salt is used as a food additive and on roads in the winter. Soda ash, phosphate rock, and potash also have a wide variety of commercial uses. Stone and sand and gravel are used in numerous industries including the construction of roads and buildings.

A detailed economic picture of the metal/nonmetal mining industry is difficult to develop because most mines are either privately held corporations or sole proprietorships, or subsidiaries of publicly owned companies. Privately held corporations and sole proprietorships do not make their financial data available to the public. Further, parent companies are not required to separate financial data for subsidiaries in their reports to the Securities and Exchange Commission. As a result, financial data are available for only a few metal/nonmetal companies and these data are not representative of the entire industry. Each commodity has a unique market demand structure. The following discussion focuses on market forces on a few specific commodities of the metal/nonmetal industry.

Metal Mining

Historically, the value of metals production has exhibited considerable instability. In the early 1980's, excess capacity, large inventories, and weak demand depressed the international market for metals while the strong dollar placed U.S. producers at a competitive disadvantage with foreign producers. Reacting to this, many metal mining companies reduced work forces, eliminated marginal facilities, sold non-core businesses, and restructured. At the same time, new mining technologies were developed and wage increases were restrained. As a result, the metal mining firms now operating are more efficient and have lower break-even prices than those that operated in the 1970's.

For the purposes of this analysis, MSHA uses the Standard and Poor's methodology of dividing metal mining into two categories: iron ore and alloying metals, and copper and precious metals. Metal mine production is valued in excess of $13 billion. Copper, aluminum, gold, and iron are the highest revenue producers of the metal industry.

Variations in the prices for iron and alloying metals, such as nickel, aluminum, molybdenum, vanadium, platinum, and lead, coincide closely with fluctuations in the market for durable goods, such as vehicles and heavy duty equipment. As a result, the market for these metals is cyclical in nature and is impacted directly by changes in aggregate demand and the economy in general.

Both nickel and aluminum have experienced strong price fluctuations over the past few years; however, with the U.S. and world economies improving, demand for such alloys is improving and prices have begun to recover. It must be noted that primary production of aluminum will continue to be impacted by the push to recycle. Recycling of aluminum now accounts for 30% of the aluminum used and this percent is expected to rise in the coming years. Due to the increase in aluminum recycling, prices have been falling and inventories rising since the mid to late 1980's²².

The market for copper and precious metals, such as gold and silver, is marked by great uncertainty and price volatility. Prices for gold and silver fluctuated by as much as 17 to 25%, respectively, during 1993. The copper market recovered substantially during 1994, posting a 3.7% growth in demand by 1995²³. The gold and silver markets, however, continue to be marred with speculative demand spurs; consistent recovery and growth have been difficult to achieve due to uncertainty of U.S. buyers and shifts in production in South Africa and Russia. In 1993, Russia began to cut back its gold production which had generated low prices in the global market since 1990.

Overall, the production from metal mining increased by about 5.5% from 1991 to 1995; 1995 estimates put capacity utilization at 84%²⁴. MSHA expects that the net result for the metal mining industry may be reduced demand but sustained prices. The 1993 average profit as a percent of revenue for the metal mining industry was about a 1.3% loss after taxes²⁵.

Nonmetal Mining, Including Stone and Sand and Gravel

Nonmetal mine production is valued at more than $24 billion. Included in this figure is the production of granite, limestone, marble, slate, and other forms of crushed and broken or dimension stone. Other prosperous commodities in the nonmetal category include salt, clay, phosphate rock, and soda ash. Market demand for these products tends not to vary greatly with fluctuations in aggregate demand. Stone is the leading revenue generator with 1995 production valued at $7.2 billion. Construction sand and gravel and industrial sand 1995 production is valued at about $4.3 billion.

Evaluating financial information for nonmetal mining operations is particularly difficult. Financial data are available only for relatively large mining operations and these often engage in a wide variety of activities of which mining is typically only a small part. Many large mining firms have financial interests in mines or mills of different commodities, thereby making it difficult to evaluate the financial aspects of any specific commodity. Publicly held firms are not required to separate financial data for their subsidiaries in their reports to the Securities and Exchange Commission and financial data are not available for most of the small mines because they are not publicly owned. (About 98% of the small metal/nonmetal mining operations are stone, sand and gravel, or other nonmetal operations.) This discussion of the economic characteristics of the nonmetal mining industry does not separately address sand and gravel, stone, and miscellaneous other nonmetal mining operations as was done in the discussion of the nonmetal mining industry's structure.

Sand and gravel and stone products, including cement, have a cyclical demand structure. As a recession intensifies, demand for these products sharply decreases. Some stability in the market was achieved during 1993 and early 1994. Demand for stone, particularly cement, is expected to grow by as much as 4.8% and demand for sand and gravel is expected to grow by as much as 2.3%.

The U.S. is the largest soda ash producer in the world with its 1994 production valued at about $650 million. Soda ash is used in the production of glass, soap and detergents, paper, and food. Both salt and soda ash have a fairly constant demand structure due to the products' uses and the lack of suitable substitutes. A 1994 industry analysis indicates shifts in the world demand for salt. European demand, impelled by the economic breakdown of Central and Eastern Europe, has declined; however, growth in demand has increased in Asia and the Far East²⁶.

Phosphate rock, which is used primarily to manufacture fertilizer, has an unusual market structure. U.S. production and exports of phosphate rock have declined in recent years and imports from Morocco increased by 180% from 1991 to 1992.

The remaining nonmetal commodities which include boron fluorspar, oil shale, and other minerals are produced typically by a small number of mining operations. Despite this fact, annual production of pumice, perlite, vermiculite, and some others is valued at the tens of millions of dollars for each product.

Overall, the production from nonmetal mining increased from 1991 to 1995; 1995 estimates put capacity utilization for stone and earth minerals at about 97%²⁷. The net result for the nonmetal mining industry may be higher demand for stone and various other commodities and increased prices. The 1993 average profit as a percent of revenue was about 3-4% for nonmetal mine production, excluding stone and sand and gravel; about 8% for stone mining; and about 5% for sand and gravel²⁸.

SUMMARY

Noise is one of the most pervasive health hazards in mining. Exposure to hazardous sound levels results in the development of occupational noise-induced hearing loss (NIHL), a serious physical, psychological, and social problem. There is a wealth of information on the relationship between noise exposure and its auditory (hearing loss) and non-auditory (physiological and psychosocial) effects. This information is discussed in more detail in the preamble to the proposed rule.

In publishing this proposed rule, MSHA expects miners and the mining community to receive numerous benefits. The greatest benefit is the reduction in the number and severity of cases of NIHL. MSHA expects that implementation of the provisions in the proposed rule would reduce the number of cases of noise-induced hearing impairment by about 67%. It would prevent about 30,590 cases of hearing impairment (765 cases per year for a 40-year working lifetime). Reduced incidence of NIHL would result in savings in the costs of worker's compensation claims, lost productivity, and medical expenses, as well as the unquantifiable costs of disruption to the lifestyle of a NIHL afflicted person.

NATURE OF THE HAZARD

Hearing Loss

Research has shown that prolonged exposure to high sound levels, such as the levels found in mining, leads to the development of NIHL. The National Institute for Occupational Safety and Health (NIOSH) has identified the ten leading work-related diseases and injuries in the publication, "Proposed National Strategies for the Prevention of Leading Work-Related Diseases and Injuries, Part 2." According to NIOSH, NIHL is among these "top ten" diseases and injuries. NIHL can be diagnosed and prevented. This proposed rule would require actions (1) to reduce the exposure of miners to hazardous sound levels and (2) to monitor miners' hearing levels so as to identify and stop the progression of NIHL.

NIHL can be temporary or permanent depending on the intensity and duration of the noise exposure. Temporary hearing loss results from short-term exposures to hazardous sound levels, with normal hearing returning after a period of acoustic rest. Generally, permanent damage to the inner ear hair cells or the auditory nerve and, thus, permanent hearing loss results from prolonged exposure to hazardous sound levels over a period of several years: the higher the noise exposure, the more rapid the loss. This damage may occur so gradually that the noise-exposed person often does not become aware of it until a substantial amount of hearing is lost.

Damage to the auditory nerve makes it difficult to hear as well as understand speech. People with significant NIHL are often frustrated by missing information that is vital for social or vocational functioning, which can produce workplace safety hazards. People around them would need to speak louder and more clearly to be understood. In addition, background noise has a much more disruptive effect on hearing-impaired individuals because they are less able to differentiate between the wanted signal and the unwanted background noise.

Once hearing is lost or diminished, the ability to discern words and understand speech cannot be restored via medical treatment, prolonged exposure to silence, or the use of a hearing aid. Although people with NIHL sometimes can benefit from the use of hearing aids, the hearing aid can never "correct" a hearing loss by restoring a person's former hearing ability. Hearing aids function primarily by amplifying sound, both the wanted speech signals and the unwanted noise, usually without making it clearer or less distorted.

Other Effects of Noise and NIHL

Although MSHA recognizes that non-auditory effects of noise can be significant, they are difficult to identify, document, and quantify. By contrast, the auditory risks have a well-established dose-response relationship and, thus, provide a solid foundation on which to base regulatory action. Numerous studies have implicated noise and NIHL as a possible causative factor in a variety of problem areas that adversely affect a person's physical and mental well-being, and can adversely impact productivity and contribute to accidents.

Recognizing these non-auditory effects of NIHL and noisy work environments, in EARLog 6, "Extra-Auditory Benefits of a Hearing Conservation Program,"²⁹ Berger suggests that an effective hearing conservation program (HCP) may not only prevent NIHL, but also improve general employee health and productivity. MSHA also believes that reducing sound levels and protecting miners from hazardous noise exposures would lessen the adverse non-auditory effects of NIHL and noisy work environments. MSHA requests data to aid in the quantification of the non-auditory impact of high noise exposures.

Risk of Impairment

The preamble to the proposed rule discusses the full range of NIHL risk estimates from available data. Among the points noted in the preamble is that all the studies of the risk of NIHL available in the literature measure the risk of acquiring a 25 dB hearing level (deviation from audiometric zero). While all the studies are consistent in this regard, not all the studies measured hearing levels using the same sound frequencies. As discussed in the preamble, MSHA believes that, in assessing the risk to workers, NIHL should be measured at those frequencies that affect a person's ability to understand speech under everyday (noisy) conditions. This is the approach taken by OSHA and NIOSH.

The following table, taken from the preamble to this proposed rule, summarizes the excess risk of developing a material impairment of hearing according to the OSHA/NIOSH definition of material impairment as discussed in the preamble.

* If exposed to the specified sound levels over a working lifetime.

Other U.S. and foreign studies have found similar levels of excess risk. MSHA believes that miners exposed at sound levels exceeding 85 dBA for a working lifetime are at significant risk of developing a material impairment of hearing.

MSHA used the risk data presented in the NIOSH Criteria Document (1972) on occupational exposure to noise, together with projected exposure profiles, to quantify the numbers of miners estimated to incur a material impairment of hearing. (See the "Quantification of Benefits" section below.) MSHA chose to use the NIOSH (1972) data for quantifying risk because

(1) NIOSH is the official primary research agency for the health of miners;

(2) the NIOSH criteria document (1972) evaluated and considered a large number of studies on occupational noise exposure to develop its risk assessment;

(3) the NIOSH criteria document presents an estimate of excess risk for a wide range of exposure levels; and

(4) a single set of risk estimates, rather than a range of estimates representing all studies considered, is simpler and clearer.

The following risk estimates are for persons aged 55 to 70 with 21 to 41 years of exposure at these levels.

* A hearing level in either ear of 25 dB or greater averaged over 1000, 2000, and 3000 Hertz.

The Agency is aware that NIOSH is currently working on revising its estimates using a different model and taking hearing loss at an additional frequency into account; but until such an approach is peer reviewed and approved, MSHA has concluded it should rely upon the 1972 estimates. MSHA will consider NIOSH's recommendations when they are published.

Sources of Exposure and Level of Risk

Permanent hearing loss can result from overexposure to the many sources of noise in mining. Research indicates that mining ranks second, after airfields at which jet engines are present, as the loudest industrial setting. These high sound levels come primarily from mining equipment, as well as from blasting and reverberations from mine walls. The following list presents typical sound levels of some types of mining equipment without noise controls.³³

For many years, the risk of acquiring an NIHL was accepted as an inevitable consequence associated with mining occupations. MSHA established standards for noise exposure in coal mines (30 CFR 70.500 and 71.800) and metal/nonmetal mines (30 CFR 56/57.5050) in recognition that this risk could be controlled. Quieter equipment, isolation of workers from noise sources, and limiting worker exposure times are among the many, well-accepted methods now used to reduce the incidence of NIHL. Despite MSHA's efforts, hearing loss among miners continues to be a problem.

MSHA's research has shown that the existing standards are not preventing material impairment of hearing among miners. Specifically, MSHA data show evidence of NIHL in a survey of coal miners. A preliminary analysis of coal miners' audiograms was conducted. Limiting the analysis to young coal miners (less than 40 years of age), who should have worked only after MSHA noise regulations were implemented, showed that about 14% are experiencing a hearing loss as defined by the NIOSH/OSHA criteria. MSHA believes that full compliance with the proposed standards for noise would prevent a significant number of NIHL cases.

QUANTIFICATION OF BENEFITS

Dual Threshold Survey

In March 1991, MSHA inspectors began collecting noise exposure samples during regular inspections using personal noise dosimeters that simultaneously accumulated dose at an 80 dBA threshold (low threshold level - LTL) and a 90 dBA threshold (high threshold level - HTL). MSHA inspectors normally collect enforcement samples using a 90 dBA threshold. Collecting samples simultaneously using both thresholds enabled the Agency to evaluate and quantify the incremental impact of a permissible exposure level based on an 80 dBA threshold. All other dosimeter settings were the same as those used during normal compliance inspections, i.e., the 90 dB criterion level, 5-dB exchange rate, and A-weighting system. MSHA refers to this inspector study as the dual-threshold survey and discusses it in greater detail in the preamble to the proposed rule.

MSHA inspectors collected about 42,000 dual-threshold samples from March 1991 through December 1994 at metal/nonmetal mines and about 4,200 samples from March 1991 through December 1995 at coal mines. The results of this study are summarized as follows.

The dual-threshold survey confirmed that integrating the sound levels between 80 dBA and 90 dBA into the noise exposure generally increases the measured noise dose. The greater the amount of noise between 80 dBA and 90 dBA, the greater the impact. For the purpose of the following analysis, MSHA used the LTL noise exposure sampling data which reflect the requirements of the proposed rule.

Methodology

In determining the number of cases of material impairment of hearing that would be prevented, MSHA first determined the number of cases of hearing impairment expected under existing exposure conditions. MSHA then determined the potential reduction in numbers of cases resulting from the installation and use of additional engineering and administrative controls as would be required under the proposal. Finally, MSHA determined the potential reduction in numbers of cases resulting from the additional use of hearing protection devices (HPDs). The following steps describe this process.

1. Baseline Risk of Impairment under MSHA's Existing Standards and Exposure Conditions

Step 1. Adjustment of Individual Data Elements

MSHA adjusted individual samples with an equivalent HTL TWA₈ reading at or above 90 dBA by subtracting 5 dBA from the equivalent LTL dBA dose. MSHA based this adjustment on the assumption that mine operators currently issue personal HPDs to miners exposed at or above the PEL, that miners are using the HPDs, and that such protection reduces the miner's equivalent TWA8 noise exposure by about 5 dBA. (As discussed in the preamble, MSHA studies indicate that the amount of reduction achieved by HPDs under conditions of use is 5 dBA³⁴.)

In addition, the adjustment for metal/nonmetal samples with an HTL reading at or above an equivalent TWA₈ of 105 dBA was 10 dBA to account for the current use of dual hearing protection.

Step 2. Sample Distribution

The distribution of LTL sampling data after adjustment for the use of HPDs under existing standards and exposure conditions is as follows:

Step 3. Exposure Profile

The estimated number of miners in each exposure range under existing standards and exposure conditions, as calculated by multiplying the percent of samples in each exposure range (See step 2, sample distribution.) by the total number of coal or metal/nonmetal miners, is as follows:

* Includes contractor employees. Does not include office workers. Discrepancies are due to rounding.

Step 4. Projected Number of Impairments

By using the NIOSH point estimates of risk to represent exposures over a range, MSHA underestimates the number of cases of hearing impairment expected to occur. For example, NIOSH estimated that the risk of incurring a hearing impairment is 3% at 80 dBA. MSHA applies this risk estimate to all exposures from 80 dBA to 84.99 dBA. In fact, the risk for exposures at 84.99 dBA would be closer to 16%, the NIOSH estimate of risk for exposures at 85 dBA.

This analysis does not take into account the movement of miners to jobs with lower noise exposures nor miners with a working life of 20 years or less. Also, this analysis does not include office workers because MSHA's sampling data does not represent this job group, and MSHA does not expect that their normal noise exposures would exceed a level that presents a risk of hearing impairment.

The projected number of impairments under existing standards and exposure conditions, as calculated by multiplying the NIOSH (1972) risk estimates for each exposure range by the number of miners in each range (See step 3, exposure profile.), is as follows:

* Includes contractor employees. Does not include office workers. Discrepancies are due to rounding.

2. Impact of Proposed Standards

A. Impact of Engineering and Administrative Controls

Step 1. Adjustment of Individual Data Elements

MSHA adjusted the values of individual LTL samples (data elements) to account for use of additional engineering and administrative controls to comply with the proposal. Adjustments were based upon the expected impact of installing additional feasible engineering controls and using administrative controls within each job group.

Coal Mining

Current enforcement efforts among coal mining operations allow the use of HPDs in lieu of engineering and administrative controls in complying with the PEL. As a result, MSHA anticipates that almost all coal miners would benefit from the installation and maintenance of feasible engineering controls because such controls reduce the overall sound level in the mine environment. For the purpose of quantifying benefits in this analysis, MSHA adjusted all coal LTL samples by at least 3 dBA to account for the overall reduction in sound levels in the mine environment as a result of the widespread use of engineering controls.

MSHA next adjusted coal LTL samples within specific job groups to reflect the direct benefit expected from engineering or administrative controls. MSHA expects engineering controls to be the primary means of control for most job groups. Depending on MSHA's assessment of the technological feasibility for the use of engineering controls in a specific job group, MSHA applied an additional adjustment of 3 to 6 dBA. For a few job groups where administrative controls are the primary control method, e.g., blasters, electricians, mechanics, the adjustment for administrative controls was 3 dBA.

Finally, MSHA adjusted those samples which continued to exceed an equivalent LTL TWA₈ of 90 dBA by subtracting an additional 3 dBA to reflect the increased use of administrative controls. Because the Agency has determined that administrative controls are feasible for most jobs at coal mines, the Agency believes that it would be feasible for mine operators to use additional administrative controls in those few situations where implementation of the usual engineering and administrative controls were inadequate to reduce a miner's exposure to below the PEL.

Metal/Nonmetal Mining

For metal/nonmetal mines, MSHA currently requires the use of engineering and administrative controls to the extent feasible to reduce exposures to the PEL. Existing standards require miners exposed above the PEL to use HPDs. In addition, MSHA policy requires those exposed at or above an equivalent HTL TWA8 of 105 dBA to use dual hearing protection. Because of this, MSHA concluded that the benefit from the additional installation and maintenance of engineering controls to comply with the proposal would accrue primarily to those miners who are only marginally in compliance with the existing standards.

For the purpose of quantifying benefits in this analysis, MSHA assumed that engineering and administrative controls had already been used to the extent necessary or feasible to reduce the noise exposure to the PEL under existing standards. Therefore, the Agency adjusted only those metal/nonmetal LTL samples where exposure levels had been in compliance using a 90 dBA threshold, and the use of an 80 dBA threshold resulted in the measured noise exposure equaling or exceeding the PEL. MSHA adjusted samples by 3 to 6 dBA depending on the Agency's assessment of the technological feasibility for the use of engineering controls in a specific job group, and by 3 dBA depending on the Agency's assessment of the feasibility of using administrative controls in the job group. MSHA experience indicates that the use of administrative controls is generally not feasible for many situations in metal/nonmetal mining.

Step 2. Sample Distribution

The distribution of LTL sampling data, after additional adjustment for implementing additional engineering and administrative controls under the proposal, is as follows:

Step 3. Exposure Profile

The number of miners in each exposure range, after adjustment for the additional use of engineering and administrative controls under the proposal, is as follows:

* Includes contractor employees. Does not include office workers. Discrepancies are due to rounding.

Step 4. Projected Number of Impairments

The projected number of impairments, after implementation of additional engineering and administrative controls under the proposal, is as follows:

* Includes contractor employees. Does not include office workers.
Discrepancies are due to rounding.

The incremental impact of the use of additional engineering and administrative controls under the proposal would be as follows:

* Discrepancies are due to rounding.

B. Impact of HPDs

Step 1. Adjustment of Individual Data Elements

If a miner's noise exposure exceeds the action level (an equivalent LTL TWA₈ of 85 dBA), the proposed rule would require the operator to provide the miner noise training, to enroll the miner in a hearing conservation program that offers annual audiometric examinations, and to provide the miner hearing protectors upon request. Miners exposed below the PEL do not have to wear hearing protectors except in a few limited situations, nor does the operator have to ensure these miners take the offered audiometric examinations. As discussed in the preamble, the purpose of these requirements is to provide additional protection for miners because (1) there is significant risk of material impairment of hearing from lifetime exposure at an LTL TWA₈ of 85 dBA; and (2) the Agency believes that it may not be feasible for the mining industry to use engineering and administrative controls to reduce miners' noise exposures to this level.

For the purpose of this analysis, MSHA assumed that all miners exposed above the action level but below the PEL would elect to request and use hearing protection. MSHA did not quantify the possible benefits from audiometric examinations. Accordingly, MSHA adjusted the values of individual samples (data elements) by subtracting an additional 5 dBA to account for this additional use of HPDs under the provisions of the proposed rule. The requirement to provide HPDs as supplementary protection when a miner's exposure exceeds the PEL remains unchanged from the existing rule. The adjusted HPD exposure profile accounts for the use of HPDs by those additional miners exposed above an equivalent LTL TWA₈ of 85 dBA, and the use of dual hearing protection by those miners exposed above an equivalent LTL TWA₈ of 105 dBA, who would not have been expected to already be using HPDs under existing exposure conditions.

Step 2. Sample Distribution

The distribution of LTL sampling data, after additional adjustment for the use of HPDs under the proposal, is as follows:

Step 3. Exposure Profile

The number of miners in each exposure range, after adjustment for the additional use of HPDs under the proposal, is as follows:

* Includes contractor employees. Does not include office workers. Discrepancies are due to rounding.

Step 4. Projected Number of Impairments

The projected number of impairments, after the use of additional HPDs under the proposal, is as follows:

* Includes contractor employees. Does not include office workers.
Discrepancies are due to rounding.

The incremental impact of the use of additional HPDs under the proposal would be as follows:

* Discrepancies are due to rounding.

C. Total Number of Hearing Impairments Prevented by Proposal

The total projected number of cases of hearing impairment that would be prevented by the proposal are tabulated below.

* Discrepancies are due to rounding.

Workers' Compensation

Society pays millions of dollars per year in workers' compensation costs for NIHL claims. As MSHA expects the proposal to reduce the number of cases of hearing impairment, we also expect industry costs for workers' compensation claims to decrease. MSHA has not quantified these benefits. Additionally, although MSHA expects a reduction in the numbers of miners suffering from noise-related physiological problems and the numbers of injuries resulting from noise-related accidents, the Agency is unable to quantify this impact and the associated reduction in medical expenses. MSHA requests data to aid in the quantification of these benefits.

SUMMARY

MSHA estimates that the proposed rule would increase the mining industry's costs by about $8.3 million annually. The proposed rule would result in a net incremental cost of about $286,685 annually for the coal industry. This amount would result from the elimination of current coal industry requirements for performing and recording biannual noise surveys and other related surveys and reports; MSHA estimates that these surveys and reports cost $5.3 million annually. Costs to the metal/nonmetal industry would rise by about $8.04 million annually.

The most costly provision in the proposed rule would require mine operators to perform annual audiometric testing of miners subjeceted to noise exposures above the PEL. This section is estimated to cost about $3.58 million. MSHA estimates that the majority of this amount is attributable to the metal/nonmetal industry ($1.98 million) because of the size of this sector. Another costly provision relates to the required use of engineering controls to reduce noise exposure to the PEL. Coal mine operators would bear the majority of this cost ($2.19 million) as coal operators would no longer be permitted to substitute hearing protectors for engineering or administrative controls to reduce noise exposure to the PEL.

For the purposes of this preliminary regulatory impact/flexibility analysis, MSHA defines a small mine as one having fewer than 20 miners and large mines as a mine employing 20 or more miners. MSHA estimates that the proposal would increase the annual costs of the average small metal/nonmetal mine by approximately 33% to $1,150 annually and increase the annual costs for the average small coal mine by approximately 10% to $1,385 per year.

The following table summarizes the net annual costs of the proposed rule by provision.

METHODOLOGY

MSHA estimated: (1) initial costs; (2) annualized costs (initial costs amortized over a specific number of years); and (3) annual costs. Initial costs consist of capital expenditures and one-time costs. Capital expenditures are defined as equipment purchase costs. One-time costs are those that are incurred once and do not reoccur annually. An example of a one-time cost would be the costs to develop a written procedural program. Initial costs are amortized at a rate of 7% over a specific number of years, depending on the provision, to arrive at annualized costs. Converting an initial cost to an annualized cost allows them to be added to annual costs in order to compute the costs per year of a rule. Annual costs are costs that normally recur annually. Two examples of an annual cost are maintenance costs and recordkeeping costs. Unless stated otherwise, annual operating and maintenance costs are estimated to be 10% of the annualized capital cost.

MSHA used an hourly compensation rate of $22.60 for a metal/nonmetal miner; $25.40 for a coal miner; $36.50 for a metal/nonmetal supervisor and $40 for a coal supervisor³⁵. These figures include benefits; but, they do not reflect shift differentials or overtime pay.

In developing these costs, MSHA took into account the fact that some mining operations currently are complying with the requirements of the proposed rule. Based on the Agency's data on current compliance and on the mine management's normal safety practices, unless otherwise stated, MSHA estimated that about 5% of small mines (coal, metal and nonmetal) and 20% of large mines are voluntarily complying with the proposal's audiometric testing requirements.

Similarly, MSHA did not include the effect of office workers in its cost calculations. Although the proposed rule would cover office workers, MSHA anticipates no separately identifiable costs or benefits to be derived by them. Costs for dose determination of office workers would be minimal. In addition, other actions such as providing hearing protection for those workers who occasionally may walk through noisy areas in the performance of their duties would create negligible costs.

SCOPE

MSHA used dual threshold data collected by the Agency from March 1991 through October 1995 to ascertain current exposure levels using an 80 dBA threshold. With current regulations, noise of less than 90 dBA is not included in computing noise exposure. Under the proposal, the threshold for counting noise would be 80 dBA. The new methodology for dose determination using an 80 dBA threshold increases the number of mines that have miners overexposed. With the new requirements and methodologies of the proposed rule, MSHA anticipates the following numbers of metal/nonmetal mines and miners would fall into each category:

* The numbers of mines and miners are based on an 8-hour time-weighted average. Office workers and contractors are not included in these totals. See the section entitled "Contractors" for more information on contract workers.

For the coal industry, MSHA also estimated the number of mines and miners at various levels of noise exposure under the proposed rule. The following table presents this information:

* The numbers of mines and miners are based on an 8-hour time-weighted average. Office workers and contractors are not included in these totals. See the section entitled "Contractors" for additional information on contract workers.

SECTION-BY-SECTION DISCUSSION

§ 62.120 Limitations on Noise Exposure

Existing §§ 56.5050, 57.5050, 70.510, and 71.805 require mine operators to use feasible engineering/administrative controls to maintain miners' noise exposure at or below the permissible exposure level of an 8-hour, time-weighted average (TWA₈) of 90 dBA, or as close to it as possible. Coal mine operators may use hearing protective devices (HPDs) as a means of meeting this level. Under the proposal, however, they would not be allowed to use HPDs unless feasible engineering and administrative controls have been exhausted.

With current regulations, noise of less than 90 dBA is not included in computing noise exposure. Under the proposal, the threshold for counting noise would be 80 dBA, the TWA₈ level for taking initial action would be 85 dBA, and the PEL would remain at a TWA₈ level of 90 dBA. The proposal also would require mine operators to determine the noise dose of each miner. The lower threshold and action levels would expand the scope of coverage of workers exposed to noisy environments and ensure greater protection. If a miner's exposure exceeds the action level, the proposal would require the mine operator to notify the miner within 15 calendar days, and to provide special training. Moreover, the operator would be required to enroll the miner in a hearing conservation program (HCP) offering annual audiometric examinations; if the miner's exposure exceeds the PEL, the operator would be required to ensure the miner takes the examinations. Also, the operator must provide any miner a hearing protector upon request; if the miner's exposure exceeds the PEL, the operator must provide a protector and ensure the miner uses it. The training, HCP and hearing protectors must meet specifications set forth in the proposal.

For the purposes of this preliminary RIA, MSHA estimates that only miners working for an operator which already has an HCP would take the annual examinations: 5% of small mines which have noise exposures above 85 dBA (310, metal/nonmetal; 60, coal) and 20% of large mines that have exposures above 85 dBA (200, metal/nonmetal; 180, coal). MSHA is assuming low initial participation because it recognizes that despite the implementation of the new training requirement, miners who work at facilities without a tradition of such tests may be skeptical of the need for them and concerned about how the results might be used, and that miners at smaller mines in particular are aware of operator cost concerns. MSHA welcomes comment on the appropriateness of this assumption.

If a miner's exposure exceeds the PEL, the mine operator would have to use all feasible engineering and administrative controls to reduce the miner's noise exposure to the PEL. If the feasible engineering and administrative controls do not reduce the miner's exposure to the PEL, the operator would have to use these controls to reduce the miner's noise exposure to the lowest feasible level. As noted, the operator would also have to provide hearing protection to the miner and require its use, ensure the miner takes the audiometric examinations, and continue to provide the annual noise training. Proposed § 62.120 would eliminate the existing clause permitting coal mine operators to use HPDs in lieu of feasible engineering and administrative controls.

Engineering Controls/Administrative Controls

To calculate the costs for engineering controls, MSHA evaluated various engineering controls and their related costs. Some engineering controls include switching to remotely operated equipment, adding mufflers and curtains to equipment, installing acoustical foam and acoustic screens around machinery, and adapting machinery with noise reducing attachments. The preamble provides a detailed review of the retrofitting options available in the mining industry.

MSHA considered the engineering controls that are used under the current rule. Metal/nonmetal mine operators have been using engineering controls extensively. The change in threshold would require such controls in additional situations and more stringent controls on others. MSHA believes metal/nonmetal operators may generally have exhausted the least costly engineering controls to comply with the current rule for some job groups. Compliance with the proposed rule for these job groups would require that the mine operator use more expensive controls--specifically, retrofit equipment--or purchase new equipment. For other job groups, however, mine operators may have used only those controls necessary to comply with the PEL and the less costly controls may still be available.

To determine the cost of engineering controls, MSHA looked at the average cost of engineering controls. Adding a muffler would cost about $100 a machine; installing acoustical insulation would be about $100 per machine depending upon its size; retrofitting machinery with noise dampening attachment would cost $800 to $1,000 on average; adapting a machine with a remote control would cost about $10,000 to $13,000.

For the coal industry, the current coal rule has permitted HPDs to be substituted for feasible engineering and administrative controls. This would no longer be permitted under the proposal; therefore, the coal industry would experience a relatively higher expense for engineering controls which is largely offset by a paperwork reduction. It must be noted that relatively inexpensive controls have not been exhausted by the coal industry as a whole.

MSHA estimates that the mining industry would spend about $3.47 million annually on engineering controls allocable as follows: metal and nonmetal industry, about $1,289,000 ($702,000 for small mines and $587,000 for large mines); coal mines, about $2.19 million ($298,000 for small mines and $1.89 million for large mines).

Metal/nonmetal mines have been using engineering controls for years. For these mines, MSHA assumed that the controls that would be used for compliance with the proposal would be the retrofitting of equipment with noise dampening attachments and remote control devices. The following table provides additional information on the estimates of engineering control costs for metal/nonmetal mines.