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By R. W. Stahl

A survey of firefighting facilities and practices in coal mines conducted by the Bureau of Mines3/ showed such variations in equipment and apparent attitude toward fire protection that a comparison with other industry seemed advisable. Although other industry is confined generally to surface operations and the hazards probably are not as great, the same general methods of extinguishment are employed, so that the cost and protection at least should be comparable. An investigation of industry other than mines revealed a generally greater emphasis placed on fire-combating equipment, fire-brigade training, fire-fighting facility inspection, and fire-hazard elimination, as well as a greater average expenditure for fire protection.

Jan 1, 1959

By Sandip K. Mukherjee

This report presents the results of the economic analysis of several applicable alternatives to increase airflow in four underground coal mines. Pressure-quantity surveys were conducted underground and measurements were also made at the main mine fan(s). The existing ventilation networks were modeled using the modified Penn State ventilation simulator. The applicable alternatives were simulated. Performance data obtained from these simulation runs were utilized to conduct the cost-effectiveness analysis. The costs for each of the alternatives included capital, operating and maintenance costs. These costs were expressed as annual ventilation costs per active section in terms of dollars per elm taking into account the economic life associated with each of the alternatives. The benefits were expressed as increased airflow quantity in the critical sections. A section of this report also deals with comparison of simulator predicted air quantity values against air quantity values measured underground. The computer outputs for each simulation run are presented in Volume II of this report.

Jan 1, 1983

By G. E. Rennick

A siphon-type laboratory airlift well was designed and operated by the Bureau of Mines to study the concurrent flow of air and oil in small-diameter pipes. Glass flowstrings ranging from to 1 inch in diameter and from L4 to 64 feet in length were equipped with various-sized air-entry jets. Liquid holdup volumes were used to correlate vertical-flow data, and empirical equations for computing gas requirements were derived. The effect of flowstring length on flow efficiency, oil- and gas-production rates, and gas-oil ratios was relatively minor at all flowing pressures. Air-jet sizes and flowstring diameters, however, had a marked effect on flow efficiency and oil- and gas-production rates. The small air-jet sizes increased maximum flow efficiency and its associated flowing pressures but decreased oil- and gas-production rates. An increase in flowstring diameter increased maximum flow efficiency with its associated flowing pressure and also increased the production rates of oil and gas.

Jan 1, 1965

By A. D. Hahn

This report describes reconnaissance by the Federal Bureau of Mines of titanium-bearing sandstone in Kemper County, Miss. The purpose was to determine the ilmenite, rutile, and associated heavy-mineral content of black-sand-bearing Eocene deltaic formations" The investigation was part of a survey of titanium resources of the United States. Ilmenite (FeTi03), an iron-titanium oxide, is the major titanium-bearing mineral consumed in the titanium pigment industry. Rutile (Ti02), titanium oxide, is used mainly in producing welding-rod coatings and titanium metal. The fieldwork was conducted during the first half of November 1959. Seven holes, totaling 304 feet of bore, from which 64 samples of cuttings were taken, were drilled in the north-central part of the county; and two holes, totaling 172 feet of bore, from which 34 samples of cuttings were taken, were drilled in the southeastern part.

Jan 1, 1961

By A. B. Clayton

The Bumpus Cove area is in Unicoi County, Tenn., about 9 miles south of Jonesboro and 5 miles northwest of Erwin. Iron and lead ores were mined in the Bumpus Cove area before the American Revolution. The production of those metals continued intermittently until 1916. In 1850 this area was the most important producer of iron in the South. In 1911 several carloads of zinc ore was recovered from old dumps and shipped to Missouri smelters. In 1913 systematic mining of zinc ores was begun and continued until 1916. After that year, mining again became sporadic and continued so until discontinued in 1943.

Jan 1, 1949

By James Noll, Sam Janisko

Underground miners are exposed to some of the highest levels of diesel particulate matter (DPM) in the United States. Therefore, it is important to monitor the exposure of miners to DPM, but it can be difficult because of the complex composition of DPM and the number of interferences. Currently, elemental carbon (EC) is used as a surrogate because it makes up a significant fraction of the DPM and is not affected by interferences. Standard measurement methods for EC can be time consuming and only record end of shift results. In this research, a laser absorption technique that enables one to measure EC concentration in near real time was shown to be a beneficial tool. The real time data showed that the fresh air being drawn into a stone mine was not properly reaching the working area and needed to be redirected to decrease DPM concentrations. The real time data also provided a more accurate efficiency ofan environmental cab compared to just using the standard method by detecting the opening of the cab's window and door. The EC optical monitor was also worn by researchers in a mine to show how it can give not only the average concentration for the shift but also reveal when and where a miner is exposed to DPM. Keywords: Laser absorption, diesel, elemental carbon, mining, exposure

By L. B. Pankratz

Present-day interest in the rare-earth elements and their compounds, for both metallurgical and ceramic uses, makes it highly desirable to accumulate basic thermodynamic data that can be applied to theoretical considerations of the processing of these substances. Such data still are seriously lacking. This Bureau of Mines paper reports the results of high-temperature heat content measurements of the sesquioxides of four rare-earth elements--europium, gadolinium, neodymium, and samarium--and of the closely related element, yttrium. The temperature ranges covered by the measurements are as follows: Monoclinic Eu2O3, 298°-1,802° K. Cubic Eu203, 298°-1,350° K. Monoclinic Gd203, 298-1,802° K. Cubic Gd203, 298°-1,550° K. Hexagonal Nd203, 298°-1,795° K. Monoclinic Sm203 298°-1,798° K. Cubic Sm203, 298°-1,149° K. Cubic Y203, 298°-1,799° K.

Jan 1, 1962

By William A. Hoffman

In This Chapter [MSHA regulations for coal mines MSHA regulations for metal/nonmetal mines OSHA regulations for tunnel construction Types of respirators used in mines and tunnels Filter materials and filter efficiencies Donning, seal checking, and maintenance Filter service life and Respirator information resources] In many cases, engineering controls are not adequate to achieve satisfactory dust levels, so respirators must be used. This chapter explains the Federal regulations governing the use of dust respirators in mines and tunnels and describes the most common dust respirators used. Filter materials and filter efficiencies for respirators are discussed. This chapter also gives some guide-lines for respirator use and recommends sources for more dust respirator information. Respirator effectiveness in reducing dust exposure usually exceeds the effectiveness of most engineering control methods. RESPIRATOR REGULATIONS [Different regulations govern respirator use in coal mines, metal/nonmetal mines, and tunnels under construction.] Coal mines under Mine Safety and Health Administration (MSHA) jurisdiction. Coal mine operators are required to meet dust standards using only engineering control methods. Typical engineering control methods include ventilation and water sprays. Respirators are not regarded as an engineering control method, so respirators cannot be used in lieu of engineering controls.

Jan 6, 2003

By W. O. Vanderburg

The leasing or tribute system has been an important factor in the development of our metal-mining industry, particularly in the gold and silver mines of the Western States. It has received its widest application in. the early history of many camps and in the last stages of many mines. The system is especially adapted to mining where the ore's occur in narrow veins or are erratically distributed in small bunches or pockets so that selective mining, hand sorting, screening, or hand cobbing is required to produce shipping or milling-grade ore. The leasing system is also applicable to the development of prospects where the owners are unable or unwilling to assume the risks of searching for ore. The virtue of the system lies in the opportunity it affords miners with little capital to get started; at the same time, it rives owners an opportunity to have their property developed at small cost.

Jan 1, 1934

By William Wiehagen

This trainer?s guide is designed as a reference manual. The purpose is to offer information and examples to skills trainers to assist them in structuring training for new operators of Walk-Thru roof bolting machines. Trainers can use this manual as a resource for helping trainees learn, understand, and apply knowledge and skills. In this sense, the guide is not prescriptive. It is designed to offer information and trigger ideas on what might be done to accelerate learning to those who are new to the roof-bolting task. On-site trainers can modify this guide to fit their conditions, machines and equipment, and work procedures. They can integrate roof control plans, company policies and procedures, and operators? manuals from the manufacturers of the original equipment into this guide. Every trainee is different and will come to the job with varying levels of relevant knowledge and skills. The trainer?s decisions on where to start, how to organize the on-the-job and classroom training portions, and when and how to offer different aspects of the training will be based on (1) a pretraining assessment of the trainee?s knowledge and skills and (2) the trainer?s experience in conducting skills training. The ?Skill Check? section might be useful for deciding where training should start among miners who have underground experience but limited knowledge of roof-bolting techniques. Every job carries a learning curve and likely has a number of ?teachable moments? where significantly new knowledge and skills can be learned.

Aug 1, 2006

By E. F. Ferrell

Gold was recovered from scrap electronic 60-40 (tin-lead) solders by drossing with aluminum or zinc at elevated temperatures. The gold, together with other metallic impurities, collected in the dross phase which could then be separated from the molten solder by skimming or filtering. Drossing upgraded the gold concentration by a factor of 10. Further upgrading was achieved by a combination of steps including an oxidation roast and either a combined cyanidation-amalgamation treatment or an aqua regia leach. The gold was then recovered in highly concentrated form from the aqua regia or cyanide solutions by cementation and from the amalgam by volatilization or dissolution of the mercury. The solder was purified by reaction with NaOH to remove dissolved aluminum or with SnCl2 to remove dissolved zinc.

Jan 1, 1976

By Robert W. Geehan

"INTRODUCTION A preliminary examination of the Argentena mine was made in 'January 1945 by an engineer of the Bureau, who recommended investigation by diamond drilling. The Bureau conducted a core-drilling project at the mine from April 30 to August 4, 1946. Claims investigated are in sec. 33, T. 24 S., R. 58 E., Mount Diablo base and meridian, in southern Clark County, Nev., about 2.2 miles west of Goodsprings.The Argentena mine has been an intermittent producer of zinc-lead-silver ore since 1926. During the war years, ore was shipped to the Government stock pile at Jean, Nev., and to the International Smelting F. Refining Co.'s smelter at Salt Lake City, Utah. The mine has been shut down at intervals because of lack of a market for mixed oxidized zinc-lead ore.The 12 holes drilled by the Bureau totaled 1902 feet. The program was designed to test for faulted portions of the ore bodies know in the mine and to test favorable areas for similar ore bodies. As a result of this program, one faulted segment of the ore body was found, and it was established that no one was present in a second fault block. Similar blocks remain unexplored in the vicinity of the mine. Two holes drilled in favorable areas several hundred feet from the mine failed to discover new ore bodies."

Jul 1, 1947

By R. S. Norman

The objective of this program was to select approximately 100 acoustic materials for flammability evaluation. Noise control programs have been initiated on several types of mining equipment and vehicles which can be used in underground coal mines. Often, the materials which are used in these noise reduction programs have not been tested for flammability properties according to the same reference standard. During this program a variety of materials were selected for measurement according to ASTM E-162 procedures. A radiant heat energy source was used to measure flammability properties of 15.2 x 45.7 cm. samples. In the absorptive materials category, 45 percent of the materials tested had a flame spread index of less than 25. For barrier, damping, and isolation materials the corresponding values were 40, 43, and 9 percent.

Jan 1, 1979

By Wm. W. Adell

"These hydrocarbons belonging to the same chemical series as methane, having the general formula CnH2n have many chemical properties in common with methane and their addition to a lean gas charges the properties and burning characteristics of the gas in the same general direction although to a different extent. The hydrocarbons of this series do not readily enter into chemical reaction with other substances and therefore are incapable of combining with oxygen or polymerizing in the disturbing system and thus cannot cause gum and room troubles commonly met with in the distribution of manufactured gas.As the number of carbon atoms in the molecule increases, i.e. in proceeding from methane throughout the series, the oxygen requirements for the complete combustion of unit volume of the gases also increases; in other words, the calorific values of these hydrocarbons (as gases) increases from methane. Similarly the specific gravity increases from methane in the same order. In Table 1 are shown some of the physical constants and properties of a few of these hydrocarbons which hive bearing on their use for enriching gas."

Nov 1, 1927

By R. L. Grayson, S. S. Peng

"Research has been conducted during the past year on a study to correlate respirable coal mine dust characteristics with worker positions and coal seams. The first characteristic of respirable coal mine dust which has been addressed in the correlation study is respirable dust mass concentration. In fulfillment of this objective, two mines operating in different coal seams have been selected for respirable dust mass sampling on both longwall panels and continuous mining sections. At present, sampling has been completed on the longwall panel operating in the first mine, and one half of the planned sampling has been accomplished on the continuous mining section.The first mine sampled is operating in the Pittsburgh coal seam. The average mining height is approximately 78"" with an average of 8"" of bottom shale being mined. The mine is primarily a longwall mine, and continuous mining machines are used to support the longwall.Figure 1 shows the layout of the longwall panel which was sampled. Intake air is coursed via the track heading up to the headgate area. The air splits at the headgate. Approximately 20,000-30,000 cubic feet of air per minute (CFM) is used to ventilate the longwall face and about 5,000-10,000 CFM is routed down the belt entry. Substantial leakage across the gob was noted during the sampling period. An average of 1800 CFM per 100 feet of face leaked through the shields into the gob from #1 shield to #112 shield. A substantial amount of leakage also occurred between the #1 shield and the solid rib of the headgate development panel. The path of the air used to ventilate the panel is shown with arrows in Figure 1. Direction of air flow was opposite to the coal moving direction on the armored face conveyor.A double-drum ranging shearer is used on the face to cut a 30-inch web of coal. Normal practice is to cut from the tailgate to headgate with the leading drum raised and the tail drum lowered for cutting bottom. After reaching the headgate, the shearer is reversed and both drums are lowered for a clean-up pass. The last 40 feet of face on the tailgate is cut on the clean-up pass.The shearer is equipped with 2 banks of 4 water sprays each and 2 large sprays on the headgate end and 1 bank of 4 sprays on the tailgate end. Additionally, sprays are located above bits on the cutting drums. Actual cutting speed was approximately 14-18 feet per minute, depending on conditions.The cross sectional area for air flow on the face was approximately 60 square feet before a pass was mined and 80 square feet after a pass was mined but before the shields were advanced. The cross sectional area at the shearer was about 35 square feet.The condition of both the tailgate and headgate of the panel was good with no signs of significant roof problems. The roof conditions along the face during the sampling period were variable. At times, as much as 3 feet of drawslate fell from the roof for a span of as much as 40 shields. Generally, however, relatively local areas of falling roof were encoun-tered, usually limited to a 10-20 shield span when appearing.Ten days were spent gathering respirable dust samples on the longwall panel. Mine Safety Appliance (MSA) sampling units equipped with 10-mm nylon cyclones, pre-weighed MSA PVC filters, and constant-flow DuPont pumps were used to obtain thesamples. The pumps were calibrated at a 2 liters-per-minute flow rate. The 10-mm cyclone was selected for classifying total dust into the desired respirable fraction in order to obtain ""legally defined"" respirable dust samples for detailed physical characterization."

Jan 1, 1988

By Clarence Hall, J. J. Rutledge

Many of the fatal accidents in coal mines have resulted from the Explosives used in Use of explosives for breaking down the coal. These accidents have resulted both from the use of explo- sives that were not suitable and from the careless or improper use of suitable explosives. Investigation has shown that one of the commonest causes of dis- astrous explosions in the coal mines in this country has been a blown- out shot of black blasting powder or dynamite. The dangers that attend the use of these explosives were perceived several years ago, and in consequence the attention of powder manufacturers was directed to the production of explosives that would be less liable to ignite inflammable gas or dust. The manufacturers have been so successful in their efforts that it is now possible to obtain explosives which yield much shorter and quicker flames than black blasting powder or dynamite, and hence are much less dangerous to use in fiery or dusty coal mines. of explosives. To find out which of the many grades of short-flame explosives Government tests have the qualities that render an explosive most effective and least dangerous for mining coal, the United States Government established a testing station at Pitts- burgh, Pa., in 1908. This station is now under the charge of the Federal Bureau of Mines. Before the station was opened a state- ment of the requirements that the explosives in question would have to satisfy was drawn up and sent to manufacturers. A number of these sent explosives to be tested, and on May 15, 1909, a list of the explosives that had passed the tests was published. Since that date other brands of explosives have been tested and three more lists have been issued. The latest list, published in Miners' Cir- cular 2, Bureau of Mines, contained the names of no less than 71 explosives that had passed the tests prior to January 1, 1911.

Jan 1, 1912

The production of harmful pollutants from coal mines and/or from coal and associated strata has been a recognizable fact in the United States for over two hundred and seventy years. In 1698, Gabriel Thomas observed(l) that the colored water flowing from streams in this country was similar to that which flowed from the coal mines in Wales. Hence, water pollutants such as acid were being produced before any known coal mines were operating in this country. The coal mining industry has contributed to the increase of pollution by exposing large amounts of sulfide materials that enable the reaction of water, oxygen and sulfur containing materials to form acid. A map of the United States coal fields can be seen on Figure 1. The anthracite regions of Pennsylvania, although small when compared to the total reserves, have produced some of the country's major water problems. The map indicates the extent of bituminous reserves of the Appalachian and midwest regions. Also evident are the bituminous, subbituminous and lignite coal reserves in the west which have recently come into greater demand. Acid mine pollution is encountered in numerous states, but the major problem is found in the Ohio, Susquehanna, and Potomac River basins.(2) Most coal beds contain some sulfur which may be in the inorganic, sulfate, or sulfide form, and thus have the potential to produce sulfuric acid. However, much of the strata that overlays the coal beds also contains acid neutralizing materials. Therefore, the amount of acid produced depends upon the amount of both acid and alkali materials that dissolve in the water in any given mine. The common sources of sulfurous material in the seam or surrounding rock are generally called sulfur balls or "nigger heads" by the miners. Sulfur balls that have been observed(3) seem to be equally divided between those containing sulphuritic iron capable of producing sulfuric acid upon oxidation and those that are primarily calcium carbonate. It has been observed in many instances that two types of water, acid and alkaline, are being produced in the same mine. A study of the geological strata and a survey of subsidence, faults and sulfur balls will usually give some indication of why this happens. The reaction of pyrite (FeS2) with oxygen and water to form ferrous sulfate (FeSO4) and sulfuric acid (H2SO4) by a series of complex chemical interactions is well documented but not well understood.(4,5) However, it is well known that the reactions to form the acid cannot occur unless all three constituents are present. Since pyrite is inherent in most coal seams and air is needed to sustain the miner, the most logical answer is to eliminate water infiltration into the mine, or to remove it from the mine before acids can form.

Jan 1, 1970

By C. Gary Reiness

A safety glass eyepiece which had been repeatedly exposed to mine environment over a number of years was studied to determine some of its optical properties. In the regions from 385 to 400 mµ and from 625 to 760 mµ, the transmittance was less than the 89 percent required by the American Standard Safety Code for Head, Eye, and Respiratory Protection. From 200 to 320 mµ the relative transmittance of two parts of the eyepiece was found to vary widely, having a maximum of 38 percent difference at 315 mµ. Irradiation of the glass by ultraviolet light caused enhanced absorption in the range from 200 to 1,200 mµ. There was a time-dependent increase of 1016 color centers per cubic centimeter throughout this range after 36.5 hours of irradiation. The rate-of-growth curve for the optical density, at 243.5 mµ and 23° C, was resolved into linear and saturable components, indicating zero order and first order

Jan 1, 1968

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of El Salvador has been prepared from the best available information in Washington , but is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State . Under the terms of the Code of Commerce ( arts . 12ff . ) , foreigners living in El Salvador can engage in business on the same terms as nationals . This involves ( = $434.00 ) - except for those with a working capital , of less than a thousand pesos inscription in the merchants ' register , which can be refused only in case of manifest disability of a permanent nature .

Sep 1, 1930

By James C. Cawley

The Bureau of Mines has empirically determined ignition probability versus current for resistive circuits in an 8.3% methane-air atmosphere. Simple ignition probability, defined as the number of ignitions divided by the total number of sparks, was determined, and the corresponding currents were recorded. The experiment was designed to minimize the probability of not observing an ignition that should occur during a series of tests. For resistive circuits in 8.3% methane-air mixtures, the experimental results indicate that ignition was not achieved below 2,000 rnA at 20 V dc, 350 rnA at 30 V dc, 150 rnA at 40 V dc, and 175 rnA at 50 V dc. The simple probability of ignition corresponding to these currents is esti-mated to be, respectively, 1.0 x 10-6, 1.7 x 10-7, 3.0 x 10-7, and 1.0 x 10-5 The ignition mechanism seems to break down below this point, implying that a threshold current value exists below which spark ignition does not occur.

Jan 1, 1987