Search Documents

By Miller, ALEX U, Edward Thomas

In March 1937 the entire country was shocked by news of an explosion of gas in a New London (Tex.) schoolhouse, which resulted in the death of 280 pupils and 14 t eachers. The Government investigators of this disaster believed that the cause was the ignition and explosion of a large volume of explosive natural gas-air mixture that had accumulated in a poorly ventilated space beneath the first floor of the main school building and that this accumulation was due to leakage from gas lin suspended underneath the floor to carry the gas supply to the school.!i/ For some years there has been a potential explosion hazard in school houses and other buildings that are supplied with water from deep wells in certain parts of Illinois. Notwi thstand.ing the disaster at New London, Tex., and the fact that there had been gas ignitions at four water wells in different parts of the State, the explosion hazard in schools and other buildings was not fully recognized until a few months after the disaster in Texas, when an explosion occurred in the settling basin of the municipal water works of Clinton, Ill., and another in a pump house of the municipal water works in Normal, Ill, The explosion in the settling tank of the municipal water works in Clinton, Ill., occurred on August 12, 1937, and a.id considerable damage to the settling tank, but fortunately no one was injured. At the time of this explosion rapairs'and aJ.terations to the water plant were in progress, and 10 men were employed in the immediate vicinity of the settling tank. Two of these men were enlarging a hole in the concrete side with an air hammer for the installation of a larger discharge line.

Aug 1, 1938

By Scott Turner

To be successful , human exertion employed for the creation of value requires power and heat ; the ability to produce concentrated power in great quantities has resulted in the relatively recent industrial development that is so profoundly affecting the world . In our commercial history , we have advanced through several stages in the selection of the most suitable fuels , continuously striving to increase the flexibility and range of energy- transmission . The easy distribution of light , power and heat is the leading factor in the decentralization of industry which promises to correct some of the serious evils that have followed in the footsteps of our commercial development . The distribution of fuel in quantity in so convenient a form and with such an attractive reliability- factor as can be had with gas , meets the modern conception of efficient service . Natural gas has been used in this country for more than a century, but recently it has attained a prominence far in excess of anything known in its earlier history. We may consider that we are now getting into our real stride in the utilization of our natural- gas resources . : In a country like the United States , wherein we are accustomed to mammoth achievements , we may be inclined to accept casually the noteworthy technical and economic advances which have resulted in the expansion of natural- gas distribution . About three years ago , the transmission of natural gas a distance of more than 250 miles from its source was first accomplished , and this was really a noteworthy engineering feat . Today , this useful commodity is being transported twice that distance , and lines are being laid which will carry gas more than 900 miles from the points of occurrence . Let us not take such outstanding improvements too much as a matter of course ; the industry should be congratulated on its long steps forward .

Oct 1, 1930

By Clarence Hall, Spencer P. Howell

This bulletin deals with the characteristic features of the principal explosives used in mining and engineering operations, and espe- cially with the tests that show the suitability of different classes of explosives for different kinds of work. The Bureau of Mines pub- lishes the report as one of a series dealing with tests of explosives and methods of reducing the risks involved in the use of explosives in mining operations. The application of explosives to engineering and mining opera- tions has increased rapidly in recent years. According to a pre- liminary report issued by the Bureau of the Census, 469,000,000 pounds of explosives was manufactured in this country during the year 1909, and the greater part of this production was used for industrial purposes. In large engineering projects and in mining operations requiring the use of explosives the selection of a suitable explosive from the many varieties offered for sale is of fundamental importance. Vari- ous considerations are involved in the selection of an explosive of proper class for the blasting to be done. Many explosives suitable for quarry work are unsuitable for use in deep mines or in close workings. In metal mining and in driving tunnels the character of the gases evolved by the explosive on detonation is an important consideration. An explosive for use in gaseous or dusty coal mines must be formulated and compounded so that its flame temperature and the height and duration of its flame are reduced enough to per- mit its being used with comparative safety. In wet workings or in submarine blasting explosives impervious to moisture are requisite. In extremely cold climates explosives that do not require thawing are desirable, provided they are equally good in other respects. An essential requirement of all explosives, especially of those for use in tropical countries, is that they shall remain stable without change in chemical or physical characteristics.

Jan 1, 1913

By D. Harrington, C. W. Owings

Each year at least one and in some years several explosions are reported as having resulted from firing of mudcapped shots in coal mines; undoubtedly a number of small or local explosions occur that are not reported; in addition there are numerous accidents, some of them fatal, attributable to this reprehensible blasting practice. It is surprising that so few explosions and other accidents from this cause occur since the practice of firing mudcapped, Even in gassy "adobe," "dobe," "sand blast," or "bulldozed" shots is widespread. mines where general blasting is safeguarded by being done with permissible explo- sives, rocks or bowlders frequently are blasted with mudcapped shots of dynamite; even if permissible explosives are used, this type of shooting is dangerous. The usual method of preparing a mudcapped shot is to place the explosive, either in loose or cartridge form, with the detonator or "cap" on top of a piece of rock or coal and cover it with several handfuls of moist clay, loam, sand, or When the shot is road dust; in many cases there is no covering of any kind. fired a dense cloud of dust, together with an intensively hot fleme, are thrown into suspension, and if the dust is explosive or ignitable an explosion or igni- tion is likely to result practically simultaneously. The presence of gas greatly increases the explosibility of the dust, as well as the probability of an ignition. Every shot, of any known explosive, fired in a coal mine without having the charge properly confined in a drill hole and tamped with incombustible stemming to the collar of the hole, is capable of initiating an explosion that may cause the death of every man in the mine. Attention has recently been directed to this unsafe practice by an explo- sion resulting from a flagrant disregard of safe blasting practices in one of our The mine had been idle for several years most productive coal-mining regions. and was being prepared for reopening on a different system of mining. Six to 10 inches of bottom coal had been left in place during former mining operations, but in the new system it was felt desirable to remove the bottom coal left in certain parts of the mine. Instead of drilling holes in the coal, loading them, and fir- ing in the usual safe manner, five or six charges of dynamite were placed on top of the coal in each of several rooms; and while the men were at the mouth of the

Aug 1, 1929

To provide accurate navigation and control of continuous mining systems.

Jan 1, 1996

By Russell J. Foster

This Bureau of Mines review focuses on the extent to which technologically and economically feasible programs in substitution, improved processing practices, including recycling, and design can achieve conservation of cobalt, chromium, manganese, and platinum-group metals, and thus reduce U.S. vulnerability to interruptions of supply. In addition, supply-side options--domestic and foreign resources, ocean minerals, and stockpiles--are identified. The report consolidates four major studies on these strategic and critical minerals sponsored entirely or partially by the Bureau in the last few years. These studies have been updated with further information from the recent literature.

Jan 1, 1985

By Maria I. De Rosa

Coal mine fires pose a constant danger to the safety of miners and to their livelihood. Underground mine fires pose an added hazard because of the confined environment with remote exits. Enactment of safety regulations [30 CFR2 75 and 771 for under- ground coal mines and surface coal operations has greatly improved the safety of miners. However, mine fires and fire injuries remain serious hazards for all coal mining operations. This report analyzes mine fires and fire injuries for all U.S. coal mining categories (underground coal mines, surface of underground coal mines, surface coal mines, and coal preparation plants) during 1990-1999. Fires involving contractors are also included in the analysis. Similar analyses (for underground coal mines only) by the former U.S. Bureau of Mines (USBM) were reported by McDonald and Pornroy [I9801 and Pornroy and Carigiet [I9951 for 1950-1977 and 1978-1992, respectively. For comparison purposes, data for 1978-1 992 are mentioned in the "Underground Coal Mine Fires" section of this report. Detailed analyses of mobile equipment fires for all underground and surface coal and metal/nonmetal mining categories during 1990-1999 have recently been reported by NIOSH [De Rosa 20041. Risk rate values (fire and injury risk rates) for the 10-year period (1990-1999) and for five successive 2-year periods within the 10-year period are derived. Risk rate values for individual states for the 10-year period are also derived. Other variables by state and time period include employees&apos; working hours, lost workdays, and coal production (underground and surface coal mines only). The number of fire fatalities is reported by time period. Variables such as ignition source, method of detection and suppression, equipment involved, location, and burning material are reported by five 2-year periods only. Furthermore, the number of fire injuries per number of fires causing injuries and total fires has been analyzed by year, ignition source, equipment involved, and location. For comparison purposes, the major fire and fire injury findings for all coal mining categories have been reported. The data in this report were derived from "Injury Experience in Coal Mining" [MSHA 1991a, 1992,1993,1994a, 1995a, 1996, 1997, 1998b, 1999c, 20001, "Fire Accident Reports" [MSHA 199 1 b,c; 1994b; 1995b,c; 1998a,c,d,e,f; 1999a,b,d,e], MSHA "Fire Accident Abstracts" internal publications, and verbal communications with mine personnel. Mining companies are required by 30 CFR 50 to report to MSHA all fires that result in injuries and fires that are not extinguished within 30 min of discovery. A small number of fires lasting <30 min without injuries reported in the "Fire Accident Abstracts" have been included in this report. The analysis in this report will provide the National Institute for Occupational Safety and Health (NIOSH), the Mine Safety and Health Administration (MSHA), and the mining industry with a better understanding of the causes and hazards of mine fires and fire injuries. It will also form a basis for developing future fire research programs.

Jan 1, 2004

By Andrew Cecala

During a recent National Institute for Occupational Safety and Health field evaluation of a newly designed filtration and pressurization system for an enclosed cab of a surface drill, it was determined that the drill operator&apos;s respirable-dust exposure was significantly increased during time periods when the cab door was opened to manually guide another section of drill steel into place to achieve additional cutting depth. Although no dust cloud was visible when the door was opened to perform this task, the drill operator&apos;s exposure was documented (over a three-day test period) to be nine times higher than when the cab door was closed. Even at this higher respirable-dust concentration, the drill operator&apos;s exposure remained well below the permissible exposure limit governed by the federal dust standard; however, an alternative method is being investigated to guide the drill steel in place in order to eliminate this increased exposure. .

Jan 1, 2008

To reduce operator exposure to noise from vibrating screens at coal preparation plants. Background Hearing loss is one of the most common occupational illnesses in the United States. In the U.S. mining industry, hearing loss is 2.5 to 3 times greater than what is expected for the average population that is not exposed to occupational noise. Furthermore, studies by the National Institute for Occupational Safety and Health (NIOSH) showed that by age 50, 90% of coal miners have a hearing impairment versus only 10% of the population that is not exposed to occupational noise. A NIOSH cross-sectional survey of coal preparation plants showed that 43.5% of employees were overexposed to noise. The study also found that vibrating screens were one of the top five loudest types of equipment at these plants?as well as the most numerous?making them a key noise source to address.

Nov 1, 2009

This manual is for use by mine operating personnel and vehicle manufacturers in the selection and proper use of automatic fire protection systems for underground metal and non-metal mining vehicles. Most of the currently available systems are manually operated, dry chemical fire suppression systems. When properly designed, installed, and maintained these systems have proven to be effective both in fire suppression and in withstanding the rugged mine environment. Portable fire extinguishers and manually actuated systems have provided adequate protection for most of the reported fire incidents. However, there have also been incidents where injuries and property losses would not have occurred if the vehicle had been protected with an automatic fire protection system. The need for reliable automatic systems exists when the operator is not present, especially when the vehicle engine is running without the operator in the cab; and also in cases where the operator leaves the vehicle to fight a small fire with a portable and is then forced to abandon the vehicle because the small fire becomes uncontrollable. In the later cases manual systems on the vehicle are never actuated. Although these incidents have been relatively few in number in the past, the increasing use of mobile diesel powered equipment and the related importance of personnel safety, high costs of the mining vehicles, and high cost of down time warrant consideration of automatic fire protection systems. The fire history data and the design concept discussed in this manual were developed under the Bureau of Mines Contract H0252038 which is part of the government&apos;s mining research safety program. The purpose of the contract was to develop a low cost, reliable, prototype automatic fire control system for underground vehicles. The industry needs were determined through an extensive mine visitation program, and the prototype system was demonstrated on a vehicle in an underground mine fire test. The system developed under this contract was specifically designed for a load-haul-dump. However, the design concept is applicable to the full general class of mobile underground mining equipment.

Jan 1, 2011

By P. Coleman, J. C. Kerkering, S. Iverson

Fault tree analysis is a systematic safety analysis tool that proceeds deductively from the occurrence of an undesired event (accident) to the identification of the root causes of that event. One recurring mine safety problem—a dozer falling into a void over a drawpoint on a coal surge pile—was analyzed using available, inexpensive fault tree programs on a personal computer. The analysis identified basic and intermediate events that led to the burial of the dozer and graphically depicted the interrelationship between these various subordinate events as well as the various chain of events leading up to the primary event. A sensitivity analysis on these probabilities showed which events had the greatest influence on dozer burial in a coal surge pile.

By M. C. Simmons, Boyd Gutorie

Desulfurization experiments at the Petroleum Experiment Station of the Bureau of Mines at Bartlesville on virgin light distillates obtained from some ‘high-sulfur’ crude oils have shown that the octane numbers of the original distillates are increased on the average about one unit, that the octane numbers of distillates with 4 ml. tetraethyl lead are increased 2 to 3 units, and that the The Petroleum Experiment Station, at the request of the Petroleum Administration for War, instigated and has in progress an investigation of crude oils of the United States to determine their possibilities for yielding straight-run distillates suitable for use as base or blending stocks to produce high octane aviation gasoline. One phase of this investigation deals primarily with so-called ‘high-sulfur’ or ‘sour’ crude oils by seeking to determine the effects of sulfur removal upon the virgin distillates prepared from these crude oils. To date, virgin distillates from several ‘high-sulfur’ crude oils from Texas, New Mexico, and Oklahoma have been prepared and desulfurized in pilot-plant distillation and desulfurization units at the Petroleum Experiment Station. The properties of the undesulfurized and desulfurized distillates were determined and compared to show the effect of sulfur removal. Results of these investigations showing the suitability of these crude oils as sources of virgin naphtha aviation base stocks have been prepared and forwarded to the Petroleum Administration for War and other approved persons. The following preliminary summary is presented to acquaint those interested not only with the present results of the investigation of several ‘high-sulfur’ Texas, New Mexico, and Oklahoma crude oils, but also to give some basic information as to certain sulfur compounds, especially their identification in straight-run distillates, their depressing effects upon the octane numbers of leaded fuels, the benefits obtained by their partial and complete removal, and some of the processes being used to effect their removal.

Nov 1, 1943

By J. R. Bartels

Operation of underground coal mine mobile equipment is usually done in a restricted workspace with reduced visibility. This work environment puts machine operators in awkward postures for tasks that require awareness of their surroundings and fast reactions to avoid hazardous situations. Using experienced equipment operators as a source, researchers conducted an investigation that developed a method to gather data on the needs and practices of machine operators while controlling the machine and the reasons for needing particular operational cues. The method used was an interview technique including a survey questionnaire and visual aids. The data gathered defined operator cues and work positions for the cutting and tramming phases of remote controlled continuous mining machines used in underground coal mines. Analysis techniques to determine which cues an operator sees from a variety of positions utilizing a computer simulation is shown to be potentially useful to the mining industry for design of work practices and workplace layout and could impact equipment design and selection for improved worker safety. Conclusions indicate that the survey was a good research tool to collect data and helped investigators understand important visual cues. Using this information, researchers were able to analyze the visual cues an operator can see from a given work position and posture.

Jan 1, 2009

By S. H. Ash

Unusual mining conditions prevail in the State of Washington because the majority of the coal seams lie on extra steep dips, and the roof and floor of the seams are of such a character as to require an excessive amount of timber- ing. The seams as a rule give off a considerable amount of methane, which makes good ventilation imperative. Due to physical conditions, supervision is costly and travel about the workings is difficult. Because of the facts stated, the accident rate has been above the average, and for some time considerable thought has been given the idea of making promotion of safety in and about the mines a responsibility to be shared equally by the employees and the management. With this idea in mind the legislature of the State of Washington, turing March, 1927, passed laws providing that safety committees be selected to function at the coal mines of the State and at the same time recognizing the fact that first-aid education is an integral part of any safety movement; legislation was passed making it mandatory to have all persons in and about the ines trained in first-aid administration. The provisions of the State mining law3 are as follows: "In every mine a general safety committee shall be selected, composed of the mine superintendent or manager of mines, one man selected by the employees or any association of employees in or around said mine, and a third member selected by these two. "The general safety committee shall elect one of the members to act as chairman and one to act as secretary. The duties of the chairman shall be to preside at all meetings of the general safety committee, enforce its rules and regulations and see that its business is conducted in a prompt and business-like manner. The secretary shall keep an accurate written record of the proceedings of all meetings, conduct its correspondence and post notices of regular and special meetings and other matters pertaining to safety. The duties of the general safety committee shall be to investigate all serious and fatal accidents; make bi-monthly.

Jun 1, 1930

By L. C. IlsLey, E. J. Gleim, F. CRAVEN

Electrical apparatus and circuits began to be used in mines about 50 years ago. A search of the literature on mining reveals that in 1882, umping was being done by electricity in some aines of England. One account tells of a small electric locomotive being used in 1882 "to drive eight corves loaded with coal" in a mine near Dresden. In an account of his visit to some English mines, en American in 1892 mentions that he saw underground electric signals, lights, pumps, hoists, and one revolving- cutter-bar 19wall mining machine,. Among the carl electrical installa- tions in the United States was an electric locomotive in the Lykens Valley Coal Co. mine at Lykens Valley, Pa., in 1887. In 1889 the Sperry electric coal digger was being tried out. Tarce mining machines were placed in the Prospect mine, East Palestine, Ohio, in 1890. An electrical pumping plant was put in oneration during 1892 in the Woodward mine of the Delaware, Lacka- rahma & Western Railroad Co. Thus we Almost coincident with the proposed use of this new servant in under- ground workings, came the thought of making it safe in gassy mines. find an account of a design for a protected stationary electric mine lamp proposed by Edison in 1831. Enclosed-type motors rere developed in the United States and shiped to English collieries about 1903. From those early beginnings there has been continuous progress until to-day one finds hundreds of pieces of specially designed electrical apparatus distributed in American coal mines and in mines of nearly all important coal-producing countries. Along with introduction of this equipment grew the idea of the necessi- ty of government aid, in standardization. In most coal-mining countries to- day the governments either directly or indirectly have a considerable in- fluence in guiding the design of electrical equipment intended for use in Pasay mine

Jan 1, 1933

By L. C. IlsLey, R. A. Kearns

As the use of electricity becomes more and more general in mining opera- tions, interest in regulations governing its application becomes greater. During the past year the electrical section of the Bureau of Mines has made a study of State regulations now in force relating to the use of electricity in coal mines. Technical Paper 271, entitled "State Mining Laws on the Use of Electricity in and about Coal Mines", has been published as a result of this study. The present paper represents a compilation of all laws relating to accident prevention with respect to electrical circuits. This group of regulations is perhaps the most important of any that relate to safety in coal mines. Its importance is shown by reference to accident statistics in Bulletin 115, (Fay, A.H., Coal-Mine Fatalities in United States, 1870-1914, Bureau of Mines, 1916), which show that about 77 per cent of the fatalities due to electricity in and about coal mines were caused by direct or indirect contact with trolley or other power circuits. In actual number this means that of 710 men killed by electricity, 546 were killed by contact with electric wires. Undoubtedly, a large percentage of these accidents might have been prevented had the wires been properly guarded. The compilation follows:

Mar 1, 1921

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

The usual run time errors occur when illegal mathematical operations are attempted by MFIRE For exam¬ple, if the user enters a negative value for the input variable HEAT to model a heat sink or cooling station, a run tame error will occur because an exponential function is employed to better model the changing temperature dis¬tribution in the airways. DATA FILE ERRORS Two types of data file errors can occur. 1 An error may occur because the input data file itself is invalid This may be caused by: The data file cannot be found due to incorrect spelling, drive, or path specification Check the spelling and path at the prompt for location of the data file. The data file contains non-ASCII symbols Check op¬eration of the text processor to insure that only ASCII characters are produced Delete all non-ASCII and/or all out of place characters. 2 Data are accepted by the program, but are incorrect for the data types or ranges or the combination causes a data inconsistency This may be due to. An invalid character is located where a numerical value is required The input data value is outside the reasonable range The input data is insufficient to build the model for simulation. The input data exceeds the capacity of the program. PROGRAM ERROR DETECTION When the program is running, tracing messages are given on the screen indicating the group and lines of data that have been read and the section of the program that is executing Program termination indicates that problems are caused by the subsequent (not read) data file section. For each detected error, descriptive message starting with * ERROR * is issued and the program terminates. When a possibly wrong value and/or its calculated intermediate result is detected, a descriptive message starting with * WARNING * is issued and the program continues. If a modification of input value or calculated intermediate result is automatically made by the program, descrip¬tive message starting with * ATTENTION * is issued and the program continues. LOCATING ERRORS If a message indicates that the error condition occurred due to the data input file, locate and correct the data item. If no error message is issued, but the simulation results are not as expected, carefully check the list of input data shown in the output file WARNING messages and ATTENTION messages may reveal an error in the input data even though the program continues to operate Insure that the default values or modifications adopted by the program run are acceptable. Anomalistic data, though not incorrect or impossible, may lead to an unusual simulation For example, making a fan unusually powerful may prevent a normal strength fire from affecting the airflow distribution in the system Much care must be employed before considering an ex¬treme case. If a message indicates that the accuracy criterion in the temperature section of the program was not satisfied, a table detailing the current parameters of airways which have large fluctuation in the average air temperature from iteration to iteration is produced If the pattern of the parameters is clearly cyclical, while the variation of natural ventilation pressure is stable or cyclical from iteration to iteration, then, most likely there is no single equilibrium stage for the event If the variation of natural ventilation pressure decreases steadily though slowly, increasing the value of data item variables MADJ or ITN (on control line number 1) may allow convergence.

Jan 1, 1990

By L. C. IlsLey

So many subjects are covered in State mine-safety regulations that any attempt to compare different State laws in their entirety would be futile. On the other hand, if one selects a single phase or branch of safety work, such a comparison may prove profitable. The subject selected for study in this paper is limited to legislation or regulations dealing specifically with safeguarding (electric) motored equipment used in gassy mines. T When one reads glowing accounts of the safety activities being carried on here and there it is easy to believe that everything which is right and proper is being done to safeguard the mine.workers; but, when one takes time to look into the weakness of many State regulations, it is evident that there is still room for improvement. Undoubtedly it would have been much better for the safety of mines if electrical equipment had been introduced into mines 50 years earlier. If electricity had been in general use when the first mine regulations were pre- pared, those formulating the rules would have covered this hazard along with other hazards, but as electricity came in at a later period, safe mine legisla- tion regarding it has been woefully neglected. Today the United States in general is far behind most other coal-producing nations in the provision of adequate safety rules or laws for the installation and maintenance of electrical equipment and wiring. Returning to the subject of our study, approximately 30 of the 48 States mine coal. More than 20 of these States' produce coal in large quantities. How- ever, of the 30 States only four, 3 Pennsylvania, Utah, Washington, and West Virginia, have laws which specially call for the use of explosion-proof types

Jan 1, 1929

By Frank E. Chase, John Rusnak, David Newman

During the past quarter century, coal mine geologists have evolved from providing a qualitative description of drill core and coal reserves into quantitative geotechnical specialists who bridge the gap between geology and engineering. In the late 1970’s and early 1980’s, hazard prediction mapping was in its infancy. At best, hazard maps identified rudimentary structures and conditions such as stream valley locations, sandstone/shale transition zones, and lineaments. A “technical disconnect” had existed between geologists and mining engineers as each profession operated largely independent of each other. Engineers did not readily integrate geology and geologic conditions, with the exception of coal thickness, into mine planning. Geologists were relied upon for reserve estimates and did not participate in mine planning or design. The employment and market slump of the 1980’s and 1990’s combined with mining more challenging reserves mandated that this gap be bridged and forced geologists to learn to speak more “numerically” to engineers so they could be understood. The purpose of this paper is to describe the procedures and thought processes used by coal mine geologists when determining various mineability and reserve extraction feasibility issues. The paper will also address underground geologic hazard mapping and prediction techniques. To achieve these objectives, the opinions and experiences of leading coal mine geologists, geotechnical and strata control specialists across the United States were solicited.

By Martin Harper

This paper concludes a five year program on research into the use of a portable X ray fluorescence (XRF) analyzer for analyzing lead in air sampling filters from different industrial environments, including mining, manufacturing and recycling. The results from four of these environments have already been reported. The results from two additional metal processes are presented here. At both of these sites, lead was a minor component of the total airborne metals and interferences from other elements were minimal. Nevertheless, only results from the three sites where lead was the most abundant metal were used in the overall calculation of method accuracy. The XRF analyzer was used to interrogate the filters, which were then subjected to acid digestion and analysis by inductively coupled plasma optical emission spectroscopy (ICP OES). The filter samples were collected using different filter holders or "samplers" where the size (diameter), depth and homogeneity of aerosol deposit varied from sampler to sampler. The aerosol collection efficiencies of the samplers were expected to differ, especially for larger particles. The distribution of particles once having entered the sampler was also expected to differ between samplers. Samplers were paired to allow the between sampler variability to be addressed, and, in some cases, internal sampler wall deposits were evaluated and compared to the filter catch. It was found, rather surprisingly, that analysis of the filter deposits (by ICP OES) of all the samplers gave equivalent results. It was also found that deposits on some of the sampler walls, which in some protocols are considered part of the sample, could be significant in comparison to the filter deposit. If it is concluded that wall deposits should be analyzed, then XRF analysis of the filter can only give a minimum estimate of the concentration. Techniques for the statistical analysis of field data were also developed as part of this program and have been reported elsewhere. The results, based on data from the three workplaces where lead was the major element present in the samples, are summarized here. A limit of detection and a limit of quantitation are provided. Analysis of some samples using a second analyzer with a different X ray source technology indicated reasonable agreement for some metals (but this was not evaluated for lead). Provided it is only necessary to analyze the filters, most personal samplers will provide acceptable results when used with portable XRF analysis for lead around applicable limit values.

Jan 1, 2007