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1. Data from the Mine Safety and Health Administration (MSHA) indicate that a total of 44,015 employees worked in underground mining locations in 2003, corresponding to 44,778 full-time equivalent (FTE) workers. • Ninety percent of underground employees (n = 39,735) were mine operator employees. • Contractors comprised 10% of all underground mining employees (n = 4,280) and comprised only 5.8% of all underground FTEs. • The majority of underground employees worked for coal operators (73.0%; n = 32,130).

Feb 1, 2005

1. In 2002, a total of 256 metal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Metal mines were the smallest mining sector,1 comprising 1.8% of all mining operations. • Gold mines comprised 44.1% (n = 113) of all metal mining operations. Other types of metal mines were copper ore (n = 31; 12.1%), iron ore (n = 25; 9.8%), and lead and/or zinc ore (n = 21; 8.2%). • Nevada is the state with the largest number of metal mines (n = 53; 20.7%).

Jan 1, 2004

By Launa G. Mallett, Charles Vaught, Kathleen M. Kowalski, Charles D. Litton, Michael J. Brnich, Ronald S. Conti, Henry P. Cole, William J. Wiehagen

How do people behave when they are trying to get out of a fire? Are escape activities different in each incident, or will most actions be predictable across events? Do persons make the same sorts of decisions whether they are responding as individuals or as group members? Because the social costs of fire-related deaths and injuries are likely to continue to rise, societal pressure for greater safety will also undoubtedly increase. There are, therefore, compelling reasons to further our understanding of action in fires. If human behavior in fire is studied scientifically and predicted according to some well-defined principles, the benefits will be significant. Design engineers could incorporate real-world findings into their plans. Equipment manufacturers could gain from insights into how their technology is actually used in fire emergencies. Safety personnel would have a better appreciation of what constitutes adequate evacuation procedures. Trainers could upgrade the content of their courses that teach escape skills. The result would be an overall improvement in the quality of fire preparedness and safety.

Jan 1, 2000

By Rudolf Kudlich

"During the coming winter, it is probable that many householders who have habitually been users of anthracite coal will be obliged to turn to some other fuel for heating purposes, because of the limited supply of anthracite. The next best fuel, from a standpoint of cleanliness and ease of operation, is coke, but here again the supply is inadequate and the householder will have to fall back on bituminous coal. Though bituminous coal has the dis¬advantage of being dirty to handle, requiring more care in firing, and of giving off considerable smoke, it will be more generally available, costs less, and in the better grades which will naturally find their way to the domestic market, is higher in heat value, and contains less ash than anthracite.Choice of CoalThere a variety of bituminous coals are available, the householder should choose a low volatile coal, such as New River, Pocahontas, or some other ""smokeless"" coal, or the British coal now being offered in the markets along the Atlantic seaboard. Though not necessary to have the coal sized, as is the case with anthracite, it will be found cleaner to use coal from which the fine dirt has been screened. If it is found that excessive dust is caused when firing the coal, this can be reduced by slightly wetting the coal at the front of the bin, as it is being used.Method of Firingusing bituminous coal instead of anthracite in the domestic furnace, it will be necessary to use an entirely different method of fir Instead of leveling the fuel bed and putting on fresh coal in an even layer over the entire fire box, the coked and partly burned coal remaining from the previous firing should be pushed as much as possible to one side of the box, and the fresh coal thrown into the empty side so as to leave some burning coal exposed. In this way the green coal is heated slowly, the volatile gases are given off gradually, and are ignited by the burninggoing to waste up the chimney unburned."

Oct 1, 1922

By R. V. Ramani, C. B. Manula, A. Owili-Eger

Recently, a collection of programs that will simulate a ventila¬tion system with extensive analyses and report-generating capabilities and error diagnostics has been developed (Didyk, 1974). It has pro¬visions to handle air injections, methane or gas emissions, and leakage. Additionally, it will solve problems where fixed and/or maximum air quantities are specified for some airways. Finally, the simulator has been structured to be extremely modular so that additions and revisions to the model can be easily made. The general aspects of the information flow and logical structure of the mine ventilation simulator are shown in Figure 14. The output from the methane emission model is input into the ventilation simulator for calculation of the concentrations in all branches of the network. The methane model and the ventilation simulator provide powerful tools for the analysis and planning of mine ventilation systems. INPUT DATA REQUIREMENTS In all of the mathematical models, several coefficients that de¬fine the characteristics of the ventilation system are used. For the ventilation simulator, these include the frictional characteristics of the ventilation regulatory devices. Considerable work has been done on the experimental determination of these coefficients for smooth pipes and well-defined mediums, but only limited data are available for actual mining conditions. FRICTION FACTORS: The frictional characteristics of mine airways affect both the dispersion of pollutants and air flow through the roadways,. They

Jan 1, 1975

By T. R. Taubert, D. H. Carlson, J. H. Johnson

"ObjectiveDevelop a portable emissions measurement apparatus to sample and measure tailpipe concentrations of diesel particulate matter (DPM), carbon monoxide (CO), carbon dioxide (COJ, nitric oxide (NO), and nitrogen dioxide (NOJ under steady-state engine load and speed conditions during a 1-minute test.BackgroundThe U.S. Bureau of Mines (USBM) has a comprehensive research program to develop ways to reduce exposure of miners to diesel exhaust pollutants. Engine maintenance has been shown to have important effects on such exposure.Accurate measurements of tailpipe emissions are becoming an essential part of a good maintenance program for underground mines that use diesel-powered vehicles. Past studies of particulates in U.S. underground coal mines have shown that DPM alone may be present at concentrations greater than 1 milligram per cubic meter (mg/m3), half the 2-mg/m3 limit for respirable coal mine dust. A poorly tuned (smoking) diesel engine may be the sole cause for respirable dust concentrations exceeding the limit. Although there is currently no standard specifically for DPM in U.S. mines, regulatory steps are underway, and significant reductions of DPM levels in both coal and metal mines will most likely be required.Tailpipe emission measurements can provide diagnostic information to identify engine malfunctions such as clogged air cleaners, faulty injectors, or incorrect injection timing. In some cases, mine vehicle tailpipe DPM concentrations have been reduced up to 50 percent by engine maintenance and adjustments.An accurate measuring instrument would also be useful for determining the effects of exhaust control devices on tailpipe emissions. Little information is currently available about the overall effectiveness of exhaust controls after long-term use. Raw exhaust concentrations with and without the control device can be measured in underground mines, and from these data a control efficiency can be calculated. Knowledge of the effectiveness of exhaust control devices over time is needed to make intelligent decisions on bow to use and maintain these devices, and when to replace them."

Dec 1, 1995

By S. P. Howell

The Bureau of lines as repeatedly called attention to dangerous practices in the transportation and opening of kogs of black blasting powder. In 1914 Diwin Higgins (Prevention of Accidents from Explosives in Metal inos, Miners' Circular 19, Bureau of Mines, p. 15) stated "canisters should always be opened by removing the bung. To use a pick or other sharp tool for cutting a hole in the canister is dangerous. After the necessary amount of powder has boon taken out, the canister should be kept closed. The powdor should always be handled at a safe distance from an open light." In 1919, Geo. S. Rice (onthly Statement of Coal line Fatalities for June, 1919, Bureau of Mines, pp. 16 to 18) calls attention to the dangers that arise in underground transportation and handling of explosives, and calls special attmtion to the danger of hauling explosives in motor trips; the unnecessary risk involved in hauling men on the trip at the same time, and the necessity of keeping open lights away from black blasting powder. In 1919 the writer (Sensitiveness of Explosives to Frictional Impact, Tech. Paper 234, Bureau of Mines, pp. 13, 15) called attention to the fact that black blasting powder is not as sensitive to frictional impact as the nitro-glycerin dynamites and the gelatin dynamites. Black powder may be ignited by direct impact and the writer believes that this may occur without presupposing a preliminary spark. It is well known, however, that black blasting powder is very sensitive to ignition by spark flame, or heated materials, and these may be produced by an electric current, by an open light, by incandescent particles from a pipe, cigar, or cigarette, by the tearing of metal sheets or scraping of metal against metal, and possibly, by other means. -- The above discussion will serve to introduce a newly recognized hazard the ignition of black blasting powder by the forcible opening of kegs with wodden tools. The details of three accidents in which kegs of black blasting powder ex- ploded instantly when a wooden tool was driven forcibly through the top of the kegs are as follows: 1. In 1915, a powder man employed by a coal mining company stated that he was opening a 25-pound log of black blasting powder by driving a hole in the top with a wooden sprag when the powder in the leg ho was opening ignitod. This caused the ignition of fifty-two additional 25-pound logs of the powder, and the fatal burning of this and another powder man. The ono making this statement lived five hours after the explosion.

Sep 1, 1920

By Launa Mallett, Charles Vaught, Kathleen M. Kowalski, Michael J. Brnich

This paper reviews research from the U.S. mining community to define issues relevant to an evolving national and international workforce and to relate them to the emergency response population. The authors further explore and relate the key problem of an aging workforce to the resultant changes and emerging physical and psychological needs of emergency workers. Finally, the authors cite examples from the mine emergency response community and mine rescue experiences to suggest practical recommendations that include both organizational and individual formats, with an emphasis on new approaches to training this changing workforce.

By H. K. Sacks

The Bureau of Mines has improved a mine dust incombustibles analyzer originally developed at the Bartlesville Energy Research Center (BERC). This analyzer provides quick, accurate analysis of the percentage of incombustible material present in dust samples taken from mine ribs, roof, and floor so that costly overdusting may be eliminated while still maintaining a proper level of incombustibles. The changes being effected on the present design of the BERC model IV rock dust analyzer should simplify its operation and calibration procedures, resulting in increased accuracy.

Jan 1, 1976

By S. B. Levin

"INTRODUCTION An exposure of large beryl crystals in pegmatite on Beryl Mountain, in Sullivan County, N. H., was the basis for investigation by the Bureau of Mines to determine the extent of the beryl mineralization and to expose other parts of the same zone that were favorable for additional beryl-rich shoots. Testing by surface cuts, trenching, and tunneling was conducted by the Bureau of Mines from August to December 1943.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to the national security and economy. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, O. C. Ralston, chief, analyzes samples and makes beneficiation tests. The field work was supervised by Paul M. Tyler, regional engineer, and John D. Bardill, district engineer. S. B, Levin was in direct charge of the project.LOCATION AND ACCESSIBILITYThe deposit is on the northeast slope of Beryl Mountain, 1 mile south of the village of South Acworth. The village, on State Highways 101 and 123a, is 12 miles northeast of Bellows Falls, Vt. The deposit is reached from South Acworth over a gravel-surfaced road and about 1,000 feet of good truck trail (fig. 1).The nearest railroad siding is at Cold River, on the Boston & Maine Railroad, where there is also a fairly modern, but now idle, feldspar mill."

Mar 1, 1948

By John D. Sullivan, Edward P. Barrett

The experimental work on the utilization of tin-plate scrap at the North- west experiment station of the U. S. Pireau of Mines in cooperation with College of Mines, University of Washington, necessitated the selection of a simple method for the determination of tin in the iron produced. Some of the standard methods for the determination of tin which were tried are given below: 1. Dissolving in acids and precipitating the tin as sulphide, igniting and weighing as Sn02. 2. Dissolving in aciis, reducing with nickel, cooling in an atmosphere of carbon dioxide, end titrating with standari iodine solution. 3. Dissolving in acids, precipitating the tin as sulphide, dissolving this sulphide in H3 and H2S04, heating until fumes of 503 are evolved, reducing with nickel or sheet lead, cooling in an atmosphere of carbon dioxide, ani titrating with a standard iodine solution.

Mar 1, 1923

To provide a practical method to reduce hand and arm injuries during roof bolting operations.

Jan 1, 2000

By S. Gallagher, A. Mayton, R. Merkel

The prolonged exposure of equipment operators to shock and whole-body vibration (WBV) is linked to cumulative back, neck and abdominal disorders. In low coal mines, space restrictions make it difficult for seat suspensions to isolate operators from shock and WBV Researchers at NIOSH's Pittsburgh Research Laboratory are responding to these issues by investigating viscoelastie foams. For the full-load case, an ergonomic seat made with viscoelastie foams can isolate the shuttle-car operator from shock at 15 Hz. Researchers used results from additional foam testing using an analytical model to identify viscoelastic foams that provide shock isolation at a frequency below 5 Hz.

By Dana Reinke, Launa Mallett, Michael J. Brnich

Some segments of the mining industry, especially underground coal, have seen a large influx of inexperienced miners in recent years. It is anticipated that this trend will reach other mining segments over the next 10 years. This paper discusses the training needs of the younger generation of inexperienced workers who have just entered or are soon to enter the mines. Currently, many trainers are of the so-called Baby Boom generation. Can these different age groups learn to communicate across the generation gap? Even trainers who have been highly effective in the past should reassess their training styles and their classroom materials to determine if they are prepared to meet the needs of these new trainees.

Jan 1, 2002

By M. D. Schlesinger

Mercury exists in coal at very low levels; the structure of coal, the vapor pressure of mercury, and its almost universal occurrence introduce unusual problems into the analytical methods. Round-robin analyses by several laboratories, each using its own techniques, indicate that the average mercury content of coal is about 0.2 part per million. Some western coals are as low as 0.05 ppm.

Jan 1, 1971

By Robert F. Randolph

Research on improving haulage truck safety, started by the U.S. Bureau of Mines, is being continued by its successors. This paper reports the orientation of the renewed research efforts, beginning with an update on accident data analysis, the role of multiple causes in these accidents, and the search for practical methods for addressing the most important causes. Fatal haulage accidents most often involve loss of control or collisions caused by a variety of factors. Lost-time injuries most often involve sprains or strains to the back or multiple body areas, which can often be attributed to rough roads and the shocks of loading and unloading. Research to reduce these accidents includes improved warning systems, shock isolation for drivers, encouraging seatbelt usage, and general improvements to system and task design.

Jan 1, 2000

By E. William Rossi, Sean Gallagher, Richard L. Unger

The purpose of this study was to examine the lifting capacity of low-seam coal miners in four restricted work postures (roof heights of 36", 40", 44", and 48"), investigate the associated metabolic costs, and to examine electromyographic (EMG) data from eight trunk muscles during the lifting procedure. Subjects were thirteen underground miners accustomed to handling materials in restricted work postures. Each subject performed two twenty-minute periods of asymnetric lifting in each of four postures during the day of testing. The. frequency of lifting was 10 lifts per minute. A specially designed lifting box incorporated microswitches in one handle of the box and another in the bottom of the box, in order to examine the trunk muscle function at specific points during the lfting cycle. The data collected will be used by the Bureau of Mines to make recommendations for lifting materials in low-seam coal mines.

By Oliver Bowles

The following discussion of waste rock utilization constitutes the fifth paper of the current series of reports on lime- plant quarry problems . As here tofore lime manufacturers are invited to cooperate to the fullest extent by supplementing the Bureau's information with the results of their own experiences and observations . Waste utilization is the key to success in many enterprises , and with a broader knowledge of this branch of the lime industry more economical operation is made possible . Your assistance in compiling additional data on this subject is solicited , and such assistance may be rendered by writing answers to the questions on the final page of this report .

Apr 1, 1923

By M. Beus, R. Iverson, A. Dreschler, V. Scott

This paper describes research to improve safety during transport of ore and waste in underground mines. Field tests are underway in mines in Idaho and Montana. Strains measured on structural support members in an ore pass provided information about total forces acting on the structure as material was dumped into it. Results show that measured static loads were considerably less than actual total weight of the material dumped and that dynamic loads were subject to many factors, such as effects of blasting to remove hang-ups. Comparisons of measurements and computer results using a particle flow code indicated that several difficulties remain before achieving realistic determinations and models of the dynamic effects of particle flow in ort: passes and impact loads on the gates. Impact loads were overestimated in computer analyses as compared to loads measured in field tests. An alternative design approach based on softening the chute and control gate assembly is being proposed.

By Gerald L. Finfinger, Syd S. Peng

Geology is an integral part of roof control, mine design, and production operations. Yet, the importance of geology, coal/rock as an engineering construction material and its properties and behavior within the planned mine areas, in overall mine production operations has not been hilly appreciated. Of all of the engineering disciplines, mining engineers work with the most challenging construction materials. They must deal with rock materials as they exist in their natural states and design mine structures without well-known and defined properties. Further complicating the design process is the variability of the in-situ rock materials with rock types and rock properties varying widely from place-to-place. Predicting properties in advance of mining is difficult and oftentimes impossible. This is why some types of roof-control failures may suddenly occur in some areas when a single roof-control technique is consistently applied to an entire panel, section, or mine. Many roof-control techniques are primarily applicable to the geological conditions that were assumed in the development of those techniques and variations of the rocker rock properties may require modification or significant redesign of the support technology.