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By Frederick L. Hoffman

Miners' nystagmus is the result of a peculiar form of eyestrain, which often results in impairment of vision and a consequent diminu- tion of the wage-earning capacity of the workman. Historically it has been pointed out by Shufflebotham that "This disease was first recognized by Gillett, of Sheffield, about 1854, although no case was mentioned in medical literature until 1861, when the symptoms were described by De Conde, a Belgian physician. Cases were reported by Pepp Müller as early as 1860, by Von Graefe in 1873, and by Bell Taylor, of Nottingham, and by Nieden in 1874. In this country (England) we are indebted to a very large extent to the observations and writings of the late Simeon Snell and for his pioneer work on this many-sided disease; in France Dransart occupies a similar position." In the treatise on "The Effects of Arts, Trades, and Professions," by C. Turner Thackrah, published in London in 1832, it is stated that- The complexion of the colliers, even after the removal of the dirt, is generally sallow and unhealthy. Their eyes, from the swelling of the lids, appear small, are affected with chronic inflammation and intolerant of full light. * Sickness and vomiting sometimes affect persons at their commencing the employ; and many, after a few years' trial, are obliged, by the injury which their health has sustained, and especially by the weakness of their eyes, to leave the mine. According to Greer, an authority on industrial diseases and acci- dents, miners' nystagmus occurs in 5 per cent of all miners, but it is quite probable that the reference is to European coal miners rather than to men employed in all branches of the mineral industry. According to the same authority, miners' nystagmus "is associated with a twitching of the eyelids and with considerable diminution of the range of movement of the eyes, and is particularly liable to occur in patients whose vision is subnormal owing to errors of refraction, especially astigmatism. It causes much inconvenience to those suf- fering from it and prevents them from following their usual occupa- tion as, owing to the movements of the eyes, everything at which they look appears to be in a state of perpetual motion, and in conse-

Jan 1, 1916

By Oliver Bowles

"The introduction into mines, quarries and manufacturing plants of machines and tools operated by compressed air has revolutionized methods of operation to an extent comparable only with that occasioned by the invention of explosives and the utilization of electricity. The use of compressed air in pneumatic tools, in rock drills, and for the operation of pumps and other machinery is well known to most miners and quarrymen, but its application as a substitute for explosives for breaking rock in a few granite quarries has received little publicity.In the region of Lithonia, a few miles from Atlanta, Georgia, is a dome of massive granite used widely for building stone and for paving blocks. The most remarkable structural feature of the granite is the absence of joints and sheeting planes. The term ""joints"" is applied to open fractures that commonly occur in rocks, usually vertical in direction or nearly so, and spaced from a few inches to several feet apart. On the Lithonia granite outcrop, however, one may walk over the bare rock surface for hundreds of feet without finding any indications of a joint, ""Sheeting planes"" are open fractures at various levels, approximately parallel with the rock surface. The presence of such planes when spaced several feet apart greatly facilitates quarrying, and where absent, as at Lithonia, the necessary fractures must be made artificially.The forcing of artificial sheeting planes is accomplished as follows: Two holes of about 3-inch diameter arc drilled close together and to a depth of about 8 feet. Two men work at these holes all summer, and sometimes part of a second summer. A very small charge of black blasting powder, not more than a spoonful, is placed in each hole, tamped with clay, and the charges are fired simultaneously with an electric battery. This starts a small fracture running outward from the bottoms of the holes. There is in most granites one direction of easy splitting known among quarrymen as the ""rift"", and as the rift direction in the Lithonia granite is horizontal the fracture follows a horizontal plane,"

Aug 1, 1920

By Rudolf Kudlich

"The realization that fuel costs, high as compared with those enjoyed prior to the war, are apparently permanent, has caused steam power plant operators to apply their best efforts towards improving the fuel economy of their plants.Though they have given much attention to the reduction in combustion losses by improving methods of firing and improved equipment, and to diminishing the heat losses by more care in maintaining clean heating surfaces and tight and adequate baffling, they have almost universally neglected the waste that occurs from discarding unconsumed combustible with the boiler refuse.This loss varies between extremely wide limits, depending on the quality of the coal, the type of plant and the firing practice in general, the higher the ash content of the coal the greater will be the amount of combustible appearing in the refuse, and the losses will be greater as the boilers are driven at higher ratings. The refuse from stoker fired boilers is apt to have a lower aver-eve percentage of combustible than that from hand fired boilers if operated at the same rating, but stoker fired boilers are usually pushed to higher ratings and the combustible in the refuse will run higher.In actual operating practice the amount of unconsumed combustible in the boiler refuse may range from a few percent to as high as forty or fifty percent. In an informal statement one well known combustion engineer estimates that the average amount of combustible in the refuse from a large stoker fired central station boiler plant is about 15 or 20%. Assuming that the coal burned contains 12% of ash, and allowing for flue dust losses, approximately two percent of the coal will be lost through this channel. The operating engineer of one large modern central power plant reports that when burning coal of about the same ash content, the average amount of combustible in the refuse was in the neighborhood of 33%, en tailing a loss of approximately 4% of the heating value of the fuel fired. Where the coal used daily runs up into hundreds of tons, an appreciable economy could be effected by recovering this percentage."

Sep 1, 1924

By Ronald D. Hill, Elmore C. Grim

Coal-haul and mine access roads are defined as any road constructed, improved or used by the operator (except public roads) that ends at the pit or bench. These roads constitute approximately 10% of the total area directly disturbed by the surface mining operation(l). In some cases, the land disturbed by haul roads exceeds the area included in the mining operation. Studies (2 and 3) of the U. S. Forest Service in eastern Kentucky show that typical contour mining roads exhibit poor alignment, excessive grades, insufficient strength and durability, and poor drainage. Mine roads in other Appalachian- States, particularly where contour mining is practiced, appear much the same as those in Kentucky. Access roads(4) were also found to be a large source of sediment. It is possible that of the sediment that finds its way into the streams as much (or even more) originates from the haul roads as from the mining operation. Most roads are built as cheaply as possible, and good road-building design and practice are ignored. Maintenance schedules are generally inadequate, and upon completion of mining, haul roads are usually abandoned, with little or no attempt made to bed them down(5 ) . Such roads deteriorate very rapidly (Figure 68). Area mining, which is practiced in flat to gently rolling terrain, presents fewer haul road related environmental problems. These roads through necessity are generally well engineered because of the heavy equipment using them, such as 240 ton (217 metric ton) haul trucks. They must have wide beds, good alignment, and adequate drainage to permit coal haulers to run at top speed during all seasons of the year. Excessive dust can be a public nuisance and a driving hazard, and it is hard on equipment. Calcium chloride and sodium chloride have proven to be effective materials for controlling dust. Two applications during the summer when the ground surface is moist at the rate of 1/2 pound per square yard (.26 kilograms per square meter) (3 1 have been suggested. Th4 most common procedure is to keep the roads wet by using water trucks. Sediment that reaches the streams can be traced to one or more of the following five basic phases of haul-road life:

Jan 1, 1974

By G. E. McElroy

"while investigating the presence of heavy strata gases* in certain mines of the East Tintic mining district of Utah, a small, local body of light, very hot gas of high-nitrogen composition was noted in one of the mines. Observations and analyses indicate that this light gas was resulting from very rapid oxidation of finely disseminated pyrite, in lead-silver sulphide ore. The gas was actually mine air which had lost a large proportion of its oxygen content by reaction with the pyrite. This body of gas was hanging in a local high spot about 5 by 5 by 5 feet in size, caused by caving, at the end of a crosscut. Fifty feet from this spot, an air current of 6000 cubic feet per minute was entering the 5 by 7 foot cross-cat from a raise from below.On account of the vapor contained in the gas, the bottom level of the gas could be plainly seen and was practically a horizontal plane, but of slightly wavy appearance, coinciding with the point where an acetylene light was extinguished. This body of gas was visited on three occasions and samples obtained by means of evacaated bulbs and by water displacement. The temperature of the gas was ap¬proximately 175 degrees P. on all three occasions, so that sampling required thick gloves and quick action. Air three feet below the vapor line had a temperature of only 120 degrees F., and a relative humidity of 27 per cent. The stratification of the air and gas mixtures was so sharply defined that the sampler could hold his head a few inches below the vapor level for an appreciable period of time without any noticeable effect other than that due to the high temperature. At one foot below vapor level, it was 135 degrees F., and the relative humidity was 30 per cent. When a candle and an acetylene light were raised into the gas from below, the candle flame was extinguished at a point two inches lower than the acetylene flume, indicating a drop in oxygen content from about 16 per cent to 12 per cent (oxygen content of normal dry air 20.05 per cent) in the distance of two inches."

Sep 1, 1921

By R. E. Head, Virgil Miller

"INTRODUCTIONRecent investigations at the Intermountain Experiment Station of the Bureau of Mines at Salt Lake City indicate that metallurgists have given little attention to the occurrence of jarosite minerals in the oxidized ores of lead and silver. These investigations have also emphasized the importance of knowing when these minerals occur in the oxidized ores, especially those containing lead, silver, and gold, as their presence is a material factor in selecting a suitable kind of treatment. Since the question of the occurrence of jarosites in oxidized ores has come to the attention of the Bureau of Mines, investigation has indicated that plumbojarosite and argentojarosite are quite common. These two minerals appear to be widely distributed and probably escaped recognition by persons who had attempted to treat certain oxidized lead ores in which the jarosite minerals represented a material portion of the metal content.Consideration of the physical characteristics of the jarosites also indicates that in many cases failure to treat some of the oxidized lead ores with success has been directly due to the fact that the greater portion of their lead and silver content was present as plumbojarosite and argentojarosite. The data and the description of these minerals given in the body of this paper indi¬cate that attempts to recover lead and silver from ores in which appreciable amounts of the metals occur as plumbojarosite and argentojaeosite would be unsuccessful if confined to gravity methods of concentration. There are un-doubtedly considerable tonnages of oxidized lead ores in the various mining regions of this and other countries, and it is quite probable that in some of these ores the metal content of lead and silver may be largely anglesite (lead sulphate) and cerussite (lead carbonate) but that they will also contain cerargyrite (silver chloride), argentojarosite, and plumbojarosite. The treatment of such ores therefore presents an important problem, since a product is discarded from ores from which the recoveries of lead and silver have been below 70 per cent which is probably too low-grade to warrant aftertreatment by any process now in use."

Apr 1, 1928

By David C. Byrne

PURPOSE: Evaluate practical technological advances in hearing protective devices for use in different mining environments. RESEARCH SUMMARY: Previous NIOSH research shows that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals. Also, miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and sex. As described in the National Occupational Research Agenda, problems created by occupational hearing loss include (1) the reduced quality of life due to social isolation and unrelenting tinnitus, (2) impaired communication with family members, the public, and coworkers,(3) a diminished ability to monitor the work environment (e.g., warning signals, equipment sounds, etc.), (4) lost productivity and increased accidents resulting from impaired communication and isolation, and (5) expenses for workers’ compensation and hearing aids. Although the elimination of hazardous noise is the ideal long-term solution to the noise problem, miners will likely need to rely on personal hearing protection in certain situations for quite some time. However, it is well known that noise attenuation provided by hearing protectors as they are worn during everyday use in the workplace is usually worse than when tested under laboratory conditions. Additionally, workers may refuse to wear their hearing protection for any number of reasons. Therefore, this project was initiated to evaluate practical technological advances in hearing protectors, with an emphasis toward optimizing the balance between effectiveness, comfort, overprotection, and communication ability. Currently, the necessary in-house laboratory facilities and research techniques are being finalized. Individual experiments are planned that involve analysis of new hearing protector technology under both laboratory and field conditions. The laboratory components are to consist of con-trolled studies using human subjects and/or an anthropometrically correct artificial test fixture to evaluate the adequacy/effectiveness of various hearing protective devices. Field studies are planned to determine the actual usefulness and practicality of the hearing protectors as used in diferent mining environments. Recommendations can then be offered to the mining community regarding correct earplug/earmuff usage that maximizes recognition of hazard/warning sounds while adequately protecting the miners’ hearing.

Jan 12, 2000

By G. R. Hopkins

"Summary An apparent decline in fuel efficiency at refineries, which first became came evident in 1930 and continued through 1933, was checked in 1933 when the average amount of heat needed to refine a barrel of crude oil amounted to 660,000 B.t.u. This compares with an average requirement of 692,000 B.t.u. In 1932 and with a low of 639,000 B.t.u. in 1929. (See fig. 1.) The improvement in fuel economy in 1933 probably was closely related to the increase of 5 per cent in crude runs to stills. As much of the fuel burned at refineries is utilized for purposes other than under crude-oil stills and in relatively stable amounts, it is evident that a material increase in crude runs will usually reflected in a decrease in average fuel requirements. Another factor which has influences fuel economy at refineries in the past is the trend in cracking, a refining process requiring more than the average expenditure of heat. In 1933 production of gasoline by cracking increased slightly, but no appreciable rise in heat requirements resulted as an equivalent amount of fuel was saved in improved technique, particularly in the field of heat exchange.Since the beginning of the refining industry, the transition in fuels has been from solid to liquid to gaseous; in other words, the leadership was first held by coal, then passed to oil, and is now held by gas. In 1933, 54.7 percent of the total heat units generated came from gas, 39.0 percent from oil (including acid sludge), and 6.3 percent from coal and coke. The principal change in the relative importance of the various refinery fuels in recent years has been the rapid growth in consumption of refinery or still gas at the expense of all the other common fuels. Still gas owes its ascendency to its cheapness and availability, and probably it would have become the primary refinery fuel years ago if recovery methods had been perfected. The relative importance of coal showed a small increase in 1933, the first gain recorded since these surveys were inaugurated in 1925. The increase in use of coal was undoubtedly due to increased operations at plants using it,"

Feb 1, 1935

By J. H. Field

Capital and operating costs have been estimated for removing sulfur dioxide from flue gases of a powerplant of 12,000-kw. capacity by liquid-purification processes, using limestone, ammonia, or sodium sulfite as the reactant. The annnonia and sodium sulfite processes yield end products that may be marketable. Coals containing about 1.5 and 5.0 percent sulfure have been considered. The sulfur dioxide content of the gases to be treated is 0.083 and 0.30 percent, respectively. Estimates have been made for 90-percent removal of the sulfur dioxide from both gases. A third instance has been considered in which 70 percent of the sulfur dioxide is removed from the flue gas of 0.30-percent concentration. The scrubbed gas would contain 0.09 percent sulfur dioxide, which might be within the permissible limit for discharge to the atmosphere in most areas. Although it is unlikely that flue gases with sulfur dioxide concentrations of less than 0.10 percent would require purification, a cost estimate for such a gas is included because an estimate is available for a British plant employing the limestone process at these conditions. Capital investment and operating costs, with no credit for products, are lowest for the limestone process for gases of both concentrations. Crediting the ammonium sulfate and sulfur produced in the ammonia process at their market prices at the end of 1956 of $32 and $28 per ton, respectively, the operating costs of the ammonia process become the lowest for purification of the gas containing 0.30 percent sulfur dioxide. The operating costs of the sodium sulfite process for purifying gas of high sulfur dioxide content approach those of the limestone process when the byproduct sulfur dioxide is credited at $14 per ton. Even if credit for products is allowed for the ammonia and sodium sulfite processes, the operating costs are higher than those of the limestone process for the gas of low sulfur dioxide content. Because of the large quantity of materials that would be produced by removing sulfur dioxide from a relatively small number of plants, credit for products should be allowed with extreme caution.

Jan 1, 1959

By John P. Powell, J. L. Eakin

"INTRODUCTION AND SUMMARYNowata County, in the northeast corner of Oklahoma, is one of the principal oil-producing counties of this stripper area. Many fields in the county were opened and much oil was produced before statehood. The location of the major fields, as defined by the Oklahoma Corporation Commission, 2/ the outline of the areas of water-flooding activity, and the location of the several projects described in detail in this report are shown in figure 1.There was some drilling in the county earlier; but it was not until after 1904, when the Secretary of the Interior confirmed as valid the leases granted by the Cherokee Nation, that the major drilling activity began. Initial development in this part of Oklahoma was in the Chelsea field in Rogers County, which adjoins Novata County on the south. The activity spread rapidly northward to the Alluwe and Coody's Bluff fields, and then to the Nowata-Claggett field. Continued exploration resulted in discovery of the Delaware-Childers field, where some wells having an initial production of 1,000 barrels daily were completed. Fields discovered and developed during the next few years included the Lenepah (Elliott), Adair, California Creek, Curl Creek, Woody, and South Coffeyville. The oil-production history of Nowata County is shown in figure 2. In assembling the data for a production curve, it was found that the combined production records for Nowata and Rogers Counties were available for 1914 to 1951, inclusive, and that records for the individual counties were available only from 1926 to 1951, inclusive. The early production figures for the counties from 1905 to 1914, inclusive, except for 1909, were calculated from the initial production statistics of the Federal Geological Survey mineral resources bulletins and production data assembled by C. H. Beal. 3/ The production values for 1905 to 1926 for Nowata County were obtained by dividing the total production for the two counties by a percentage factor derived from known facts regarding the oil industry in the area. Production figures for the individual counties from 1926 to 1933, inclusive, were obtained from the files of the Oil and Gas Journal, and the figures from 1933 through 1951 were obtained from monthly reports of the Oklahoma Corporation Commission."

Jun 1, 1952

By Richard L. Sayrs

"The Stiner zinc prospect near the north boundary of Union Tennessee, and the Bunch Hollow property 5 miles northeast in Claiborne County, Tennessee, were diamond-drilled by the Bureau of Mines during the period .September 1, 1944, to February 22, 1945. Seventeen holes totaling 5,687 feet were completed, 13 of which, totaling, 5.083 feet, were on the Stiner property and the remainder, totaling 604 feet, at Bunch Hollow.The Stiner prospect is about 1 mile east of the old workings known as ""New Prospect"" or ""Lead Mine Bend."" The Federal Geological Survey made a study' of the area early in 1944. The prospect was first visited in August 1944 by Bureau of' Mines engineers3/ accompanied by members of the Federal Geological Survey.4/ The locality is reached by traveling State Road 33 north-about 9 miles from Maynardsville, Tenn., thence northwest about 7 miles by an improved county road that leads to the mine (fig. 1). The tract comprises an area of about 181 acres held by G. S. Stiner of Sharps Chapel, Tenn.; it is now under option to the Universal-Exploration Co. of Jefferson City, Tenn.The Bunch Hollow property, about 5 miles northeast of the Stiller prospect, was also studied by the Federal Geological Survey previous to being;Visited by Bureau of Mines engineers in August 1944. It is reached by traveling north from Maynardsville, Tenn., on State Road 33 about 13 miles, thence northwest by county road 6 miles to the property (fig. 1). The last 3 miles of the county road are in poor repair but are passable during the entire year. The property comprises an area of approximately 300 acres and is held by the imperial Mining Co., Pressman's Home, Tenn.Few reliable data are available as to the history of the Stiner prospects themselves. However, the New Prospect mine, 1 mile west, has had a colorful past, This mine was opened in 1883 and was worked intermittently until 1918, by which time more than 65,000 tons of concentrates had been shipped. No further work was done until 1942, when the mine pillars were robbed and 1,900 tons of ore averaging 25 percent zinc was shipped to the New Jersey Zinc Co., Austinville, Va."

Apr 1, 1946

By M. D. Aldridge

This document reports the results of a two-year research effort aimed at improving communication systems used in coal mines. This work was conducted under a program whose original goal not only involved the development of practical and effective electronic systems for operational communications, but also for monitoring, at a central location, remote instruments at key positions in a mine. About half way through the originally proposed three year effort, the program was redirected to phase out the communication effort at the end of two years and to concentrate the program" resources on the investigation of new monitoring system concepts developed by this research. Thus, the work reported here is incomplete relative to the originally pro- posed program. However, the work was carried to the point of providing sufficient evidence to aid in the comparison of certain new communication concepts. For the concepts chosen for this study, the work was stopped short of hardware development and field testing, Several reports in the form of Master's theses and a Doctoral Dissertation have resulted from this research. They each report in considerable detail the results of several individual" contributions to this program. In preparing this report, an attempt has been made to provide a complete description of the significant results but with- out burdening the reader with the minute details. These more detailed reports are referenced heavily for the convenience of those interested. PRESENT COMMUNICATION METHODS Two types of communication systems are presently used In coal mines. They are: 1, Various forms of telephone systems, and 2. Carrier current radio systems using the trolley line as the interconnection circuit. Carrier current radio is used almost exclusively for control of rail trafflc by the dispatcher. Almost all other communication uses the telephone system, Telephone lines generally extend to areas where trolley lines are not present such as the outside offices and warehouse. Therefore the telephone system provides the primary means of voice communication. Telephones - Telephone systems employed in American coal mines fall into three categories. 1. Paging type telephone systems - these systems have individual stations which use battery powered transistor audio amplifiers to boost signal levels for normal communication. When in the page mode,

By S. H. Ash

THE ANTHRACITE region of Pennsylvania contains over nine-tenths of the total anthracite deposits of North America and produces all but an insignificant proportion of the total output of anthracite in the Nation. The whole economy of the northeastern section of the United States depends, to a large extent, on the mining of Pennsylvania anthracite, which is shipped to New Jersey, New York, and New England and is a principal source of energy and heat for that entire region. The responsibility of the Federal Government for developing an engineering method that will prevent inundation of the Pennsylvania anthracite mines and keep them in operation has long been recognized. To obtain a reliable picture of the anthracite-mine-water problem and to solve that problem, it is necessary to have factual data on the volume and the quality and character of the mine water handled by the pumping plants in the anthracite region, as well as the kinds of pumps utilized and problems concerning their operation.

Jan 1, 1953

This report summarizes the results of a research project entitled "Fatal Accident Data Base Development." This project is the last project under Contract No. S0110601. Volumes I and 1I, "Industrial Engineering Study of Hazards Associated with Underground Coat Mine Production," summarize the original industrial engineering project and the Fatal Accident Report Analysis project. These projects were completed and accepted by the U.S. Bureau of Mines on December 10, 1971. Both volumes of the report have been made available by the Bureau to the public through the U. S. Department of Commerce technical information service. Another project under the same con tract, entitled "Equipment Operations Safety Study, ' was completed in January 1972 and the report was accepted by the U. S. B. M. at that time. The analysis in this Natal Accident. Data Lose Development report is closely related to analysis in both of the earlier reports. The original project involved an industrial engineering and safety of production operations for a representative sample of underground bituminous coal mines. The contactor was required to make recommendations 'in work practices, mining methods, equipment, and safety practices which can effectively reduce the fatality rate from rib and roof falls.' (Longwall mining methods were excluded from the study.) Time study and work element analyses were performed in over 50 mines as part of the field data gathering effort. Another requirement of the study was to develop sets of multiflow. Process charts, which are diagrammatic illustrations of the time-related interaction of mining, cycle job elements.

Jan 1, 1972

By David C. Byrne

PURPOSE: Evaluate practical technological advances in hearing protective devices for use in different mining environments. RESEARCH SUMMARY: Previous NIOSH research shows that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and sex. As described in the National Occupation-al Research Agenda, problems created by occupational hearing loss include(1) reduced quality of life due to social isolation and unrelenting tinnitus,(2) impaired communication with family members, the public, and coworkers, (3) diminished ability to monitor the work environment (i.e., warning signals, equipment sounds, etc.), (4) lost productivity and increased accidents resulting from impaired communication and isolation, and (5) expenses for workers’ compensation and hearing aids. Although eliminating hazardous noise is the long-term solution to the noise problem, miners will likely need to rely on personal hearing protection in certain situations for quite some time. However, it is well known that noise attenuation provided by hearing protectors as they are worn during everyday use is usually quite different (i.e., worse) than when tested under lab conditions. In addition, workers may refuse to wear their hearing protection for any number of reasons. This project was initiated to evaluate practical technological advances in hearing protectors, with an emphasis on optimizing the balance between effectiveness, comfort, over protection, and communication ability. The recently completed auditory research facility is now under-going the accreditation process conducted by the National Institute of Standards and Technology under the National Voluntary Laboratory Accreditation Program. Experiments are planned to investigate the factors that affect a miner’s ability to hear hazard and warning sounds (e.g., roof working, alarm signals, spoken communications, etc.). A service contract has been initiated to record and digitally store samples of typical warning sounds heard in an underground coal mine. This information will be analyzed in the lab to develop recommendations that can be offered to the mining community regarding correct earplug/earmuff usage to maximize there cognition of hazard and warning sounds while adequately protecting the miners’ hearing.

Jan 12, 2001

By R. V. Ramani, J. M. Mutmansky, J. Qin, J. Organiscak, R. Bhaskar

"The results of a two—year research study into the relationship between quartz dust levels in host material and in respirable dust in continuous mining sections are presented in this paper. The experimental design and sampling procedures for underground data collection are outlined. The sample analysis procedures for quartz determination, the ¬analysis results and conclusions of the study are discussed.The results of the study indicate that the quartz contents of the airborne dusts are generally higher than those in the host material and bulk samples; and the quartz content increases with decreasing size of the airborne dust. The source for quartz appears to be the roof and the floor materials rather than the coal seam itself. It also appears that the material containing quartz may be breaking into a different size distribution than coal.INTRODUCTION Without doubt, the potential for permanent and severe health damage exists due to respirable dust in the work environment. The attention directed at the reduction of respirable airborne dust to levels below those specified in the law and the achievements to date in meeting these standards are but a reflection of the recognition by many parties government, industry, and labor - of this potential and the need to reduce it.The ambient dust standard in underground U.S. coal mines (2 mg/s3) has a qualifier (Code of Federal Regulations, Title 30, Part 71.101) to determine an applicable dust standard when a respirable dust sample contains more than 5% quartz. This standard is frequently referred to as the ""reduced standard."" The reasoning behind the reduced standard is the relative toxicity of the quartz dust compared to that of pure coal dust. As the quartz levels in samples increase, the applicable standards become more stringent and maintaining the workings in compliance becomes increasingly difficult.The number of underground work locations operating under the reduced standards has shown a dramatic increase since 1980 (Figure 1). For comparison purposes, there were no mining entities operating on reduced standards prior to 1977. The emergence of this problem, which affects the health and safety standards on one hand and creates severe compliance problems on the other, has been rapid."

Jan 1, 1990

By Joan Weinberg

Real gross national product (GNP) grew at a seasonally adjusted annual rate of 2.2% in the third quarter, down from a revised 3.0% in the second quarter, according to preliminary data from the U.S. Department of Commerce (table 1). The slowdown in the rate of growth was attributed to the summer drought, a larger trade deficit, and a decline in Federal spending for defense. Exports slowed from the second quarter, as the dollar, compared with other industrial country currencies, edged up. Imports of both consumer goods and capital goods rose sharply, with consumers buying more foreign cars, computers, and electrical machinery. Although net exports of goods and services deteriorated slightly from the second quarter, the U.S. trade position continues to be much improved from 1987 and first quarter, 1988. Business spending for new plant and equipment rose at a 4.6% pace, well below that recorded earlier in the year. The 3.5% increase in consumer expenditure was accounted for mainly by nondurable goods and services; expenditure for durable goods--those products lasting more than 3 years--rose only 0.4%. Inflation, as measured by the fixed-weighted GNP price index, rose at an annual rate of 4.9% in the third quarter. Prices rose slightly less than they had in the second quarter, when inflation reached a 6-year high. In September, 1988, the President signed a U.S.-Canada free trade agreement (FTA) which will eliminate all tariffs and most nontariff barriers between the two countries by 1999, thereby creating the world's largest open market. In 1987, U.S.-Canadian bilateral trade totaled $161 billion. The expansion of trade is expected to generate 5% higher growth for Canada and up to 1 % higher growth for the United States by the end of the century. The higher growth for the United States translates into an estimated 750,000 jobs, and $2.4 billion in exports. Canadian parliamentary approval of the agreement is still required before the treaty can take effect. The debate in Parliament is continuing, and the issue is not expected to be resolved until after the November 21 election.

Jan 1, 1988

By Steven J. Page

Since 1982 standard calibration materials recommended for respirable crystalline silica analysis by the Mine Safety and Health Administration (MSHA) P7 Infrared Method and the National Institute for Occupational Safety and Health (NIOSH) X-ray Diffraction (XRD) Analytical Method 7500 have undergone minor changes in size distribution. However, a critical assumption has been made that the crystalline silica in ambient mine atmosphere respirable dust samples has also remained essentially unchanged in particle size distribution. The objective of this work, therefore, is to compare recent particle size distributions of underground coal mine dust and the silica component of these dusts with estimated aerodynamic particle size distributions of calibration standard materials MIN-U-SIL 5, Berkeley 5, and SRM 1878 used by two crystalline silica analysis techniques. This work provides resolution to a previously reported discrepancy involving the proper sample dilution for the particle sizing method used. Dust impactor sampling data for various locations in 13 underground coal mines were collected between 1991 and 1998 and analyzed for the respirable mass median aerodynamic diameters. The data suggest that the MSHA P7 Method will underestimate the silica content of the sample by at most 8.5 % in the median size range of 0.9–3.6 µm and that it is unlikely one would obtain any significant error in the MSHA P7 Method analysis when the method uses Berkeley 5, MIN-U-SIL 5, or SRM 1878 as a calibration standard material. The results suggest that the NIOSH Analytical Method 7500 would be more appropriate for a dust sample that is representative of the total (no cyclone classifier) rather than the respirable airborne dust, particularly since the mass fraction in the size range below 4 µm is usually a small percentage of the total airborne dust mass. However, the NIOSH Analytical Method 7500 is likely to underestimate the silica content of an airborne respirable dust sample by only 5–10 %. The results of this study also suggest that any changes that may have occurred in the median respirable size of airborne coal mine dust are not significant enough to cause any appreciable error in the current methods used for respirable crystalline silica analysis.

Aug 3, 2005

By S. J. Hemberger, F. W. Lee, J. H. Swatz

"INTRODUCTION This investigation was undertaken in 1939 for the purpose of securing the necessary information relating to the field techniques and accuracy that would be needed for magnetically surveying State-wide areas. The Florida,peninsula was chosen for such a study for two reasons: First, because it is geologically ideal for such an investigation, since it comprises a series of unconsolidated, flat-lying Tertiary and Cretaceous sediments of low magnetic susceptibility covering a complex and much-folded crystalline basement comprised of rocks carrying strongly -paramagnetic materials; second, because information concerning the structural trends of the crystalline basement would be of great interest and Importance in the study of Appalachian orogeny and the relationship of the Florida Peninsula to both the Appalachian and Antilleantectonte systems. The results of this magnetic survey have clearly demonstrated that the magnetic anomalies reflect variations in the crystalline a basement. To the degree which the structures of the crystalline basement control the structures of the overlying sediments these results are useful for oil exploration.MAGNETIC OBSERVATIONSAll magnetic measurements were made with a vertical Aekania magnetic variometer having a temperature compensated needle. All observations were tied into two base stations located at Fort. Myers and Gaineeville, Fla. The absolute vertical magnetic intensities at these two bass stations were determined by the United States Coast and Geodetic Survey within an accuracy of + 10 gammas. The accuracy of the base station variometer used in the present survey was of the order of ± 3 gammas. The sensitivity throughout the survey of the magnetic variemoter used on the traverses approximated 30 gammas per scale division and it is estimated that the probable error between stations along a traverse would be about + 5 gammas. Measurements were started on traverse C near Fort Myers and tied into the Fort Myers base station established by the Coast and Geodetic Survey. Twelve traverses, comprising 1,500 station observations, wore occupied between the Fort Myers and Gainsville base stations. When the cumulative total of these 1,500 interim observations was tied into the Gainesville base station it was found to differ by only 30 gammas from the value obtained by the Coast and Geodetic Survey for that base. The observations were adjusted for this difference."

May 1, 1945

The concept of isokinetic measurement of strength was originally related by Hislop and Perrine.(1)Characteristics of an isokinetic exertion are constant velocity throughout a predetermined range of motion. Strictly speaking, a means of speed control, and not a load in the usual sense, is applied in isokinetic exertions.(1)However, load and resistance are definitely present in this technique. In this case, the load is a result of the energy absorption process performed by the device to keep the exertion speed constant. The device prevents energy from being dissipated through acceleration in isokinetic exercise. The energy is instead converted into a resistive force, which varies in relation to the efficiency of the skeletal muscle. Since the speed of motion is held constant in isokinetic exercise, the resistance experienced during a contraction is equivalent to the force applied throughout the range of motion. For this reason, the technique of isokinetic exercise has sometimes been referred to as accommodating resistance exercise. This type of exercise allows the muscle to contract at its maximum capability a tall points throughout the range of motion. At the extremes of the range of motion of a joint, the muscle has the least mechanical advantage, and the resistance offered by the machine is correspondingly lower. Similarly, as the muscle reaches its optimal mechanical advantage, the resistance of the machine increases proportionally. It must be understood, however, that while isokinetic devices control the speed of the exertion, this does not assure a constant speed of muscle contraction. The speed of isokinetic contractions is constant during individual exertions; however, it is also possible to compare muscular performance over a wide range of isokinetic velocities. Increasing the isokinetic speed of contraction will place increasing demands on Type II muscle fibers (fast twitch and fast oxidative glycolytic). Workplace Assessment It is clear that isometric strength testing cannot substitute for dynamic strength assessment when examining highly dynamic occupational job demands. As most industrial work tasks contain a significant dynamic component, analysis of isokinetic strength capabilities appears to offer some advantage to isometric testing in this regard. However, it must be recognized that isokinetic devices are not entirely realistic compared with free dynamic lifting in which subjects may use rapid acceleration to gain a weight-lifting advantage.

Jan 1, 1998