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By R. V. Ramani, V. T. Burgos, J. A. McClay

Cost System The cost system reported here is a suite of computer programs which incorporates the logic and information flow structure as outlined in earlier chapters. Specifically, computer programs have been devel¬oped to: 1. compute labor, operating, and capital costs, 2. summarize cost and production data, and 3. compute the minimum acceptable selling price for coal. While the cost system can be executed independently, it is de¬signed primarily for use with the Master Design Simulator and there¬fore must conform to the overall system hardware. The computer model is written in Fortran IV for use with the IBM System 360/370 computers as well as with compatible units such as the Univac 1110 and CDC-6600. For ease in error detection and program modification, the model was constructed with a main routine and eight subroutines. The main routine reads and stores the data necessary for the cost computations and calls the subroutines in logical sequence. The subroutines perform the cost computations and data adjustments for reporting purposes. Each subroutine performs the cost computations for its particular com¬ponent of the cost cycle. The program operations are described in the following narrative outline. Control Subsystem As previously described, the main routine is a passive element, reading and storing input data and directing execution to the active subroutines for cost calculations. Figure 10 is a macro-flow diagram

Jan 1, 1975

By F. R. McDonald

The compound ?-valerolactone has been identified in an acid fraction isolated from waste water collected from an in situ oil-shale retort. Infrared, nuclear magnetic resonance, and mass spectrometry were used by the Bureau of Mines to confirm the identification of a subfraction collected from a gas chromatograph.

Jan 1, 1974

By Roy L. Wilfong

Infrared reference spectra are presented of compounds of importance in lead sulfide flotation research. Included are the spectra of several short chain alkyl xanthates of lead and zinc, the corresponding dixanthogen compounds, and the common oxidation products of lead sulfide and their sodium analogs. The spectra of several frequently used industrial flotation reagent xanthates are also presented. A thorough, well-documented discussion is given of the various corrections made to correct the as recorded absorption band data to near absolute values.

Jan 1, 1974

By F. R. Cattoir

This report presents the results of preliminary studies for the evaluation of some fused-salt electrolytes for refining tungsten metal, and describes the equipment used. Some impurities could be eliminated with electrolytes composed of sodium chloride, sodium iodide, or sodium tetraborate in combination with tungstic oxide or sodium tungstate. Electrolytes composed entirely of chlorides were unusable because of the volatility of tungsten chloride. Refining 96-to 98-percent tungsten to produce a commercial grade was more successful than further refining of 99.9-percent tungsten. No electrolyte tested yielded a product pure in all respects. Electrolyte temperatures of about 900° C were necessary to maintain a good dissolution rate at the anode and acceptable cell operation. Cathode current densities at the beginning of a deposition cycle were limited to approximately 1 ampere per square inch. Higher current densities resulted in a finely divided product that frequently failed to adhere to the cathode. The most conspicuous impurities in the tungsten produced were carbon, iron, and molybdenum; the former two came from the iron cell and the graphite cell liner. Electrolytes com-posed of tungstic oxide or sodium tungstate in sodium iodide, or 2Na, 0.B203, were capable of producing tungsten carbide.

Jan 1, 1963

By F. W. Davis

For some years this subject has been of interest to metallurgists. Previous to the War some work was done in :Belgium. on the enrich.ntSnt of the blast with oxygen i.."'l. connection with the smelting of iron orei.; in the blast furnace. In the United States, the late .J. E. ,Joh."lson, .Jr., \ve.s :interested in the possible use of 0J1.:ygen for metallurgical operations ar.:i cerried on some experic:.ental work along these lines pre..,,-ious to his de.e.hft Dr. F. G. Cottrell, formerly Director of the :Bureau of Mines, De7?,H''(;:,-of,,:a:t: of the Interior, and now Direc'cor of the Fixed lifi trogen Itesearc:l-1 La -:c r;a.-o='Y, Depart­ment of .Agriculture, first directed. the Eurec:ru 1 s attention to this subject. When it first began this work, the Director of the Burea.t1. of Mines, beca11se of his interest in this investigatio:::i, asked :Mr. M. H. Roberts: Vice-President of the FraU:din Railway Supply Company to select an Advisory Corr:nittee to work with the BJ::eau on tl1is subject; it also asked Mx-. Robez·ts to act as Cha.irman of this C<)1.,_1l!lHtce. T!le personneJ. of the Comrnitee which was selected. by r. Roberts is as follows:

Jul 1, 1923

By H. W. Kilau

Thermodynamic calculations indicate that an electrochemical cell might serve as an analytical device for determining the composition of high-purity metals. An equation, readily derived, for the cell voltage, E, is as follows: [E I RT In F NFe unknown sample T of L NFe standard] The cell, however, must come to equilibrium, must be reversible, and must have no thermal effects or complicating side reactions whose magnitude is indeterminable. This Bureau of Mines investigation explores the feasibility of an electrochemical technique for the analysis of high-purity iron. Experiments were conducted using room-temperature aqueous cells and high-temperature molten salt cells. The room-temperature cells proved to be irreversible. The high-temperature cells utilizing FeCl2 and a eutectic mixture of KC1-LiCl were reversible, but did not attain a constant voltage necessary for analytical considerations.

Jan 1, 1963

Control the release of ground-water into active underground coal workings by short-term pumping from dewatering wells sited on fractures. Approach The sudden release of fracture-stored groundwater into underground coal workings often occurs when mine workings are developed beneath fracture valleys, Pumping from fracture trace-sited dewatering wells, prior to development of the underlying workings, can be an efficient means of intercepting fracture-stored groundwater before it is released into the mine. Dewatering operations are discontinued once the underlying mine workings have been fully developed, and the maximum possible reduction in fracture storage has been achieved through pumping. How It Works An aerial photographic technique known as fracture trace analysis is used to site dewatering wells on rock fractures in a valley bottom. Downhole caliper and temperature logs are used to assess the fracture flow potential of each dewatering well drilled.

Jan 1, 1987

By John Nagy, Henry G. Dorsett, Murray Jacobson

Laboratory studies show that ignition of a dispersed combustible dust in an open vessel may be prevented by adequate inerting . Factors affecting the inerting requirements are -- dust concentration , spark energy , ignition temperature , composition of the substances used for inerting , fineness of dust and type of combustible . The oxygen concentration of the atmosphere and in some instances the proportion of admixed inert powder and moisture required to prevent ignition are given for 367 dust samples . Variations in inerting requirements with strength of igniting source are discussed .

Jan 1, 1964

By J. M. Stuve

Calorimetric determinations of the low-temperature heat capacities, standard enthalpy of formation, and high-temperature enthalpies were made of (Na20)4 ?Fe20,(c). The resulting values of entropy (S°), enthalpy of formation (?Hf°), and free energy of formation (?Gf°) at 298.15° K are 104.676 cal/deg mole, -656.2 ±.kcal/mole, and -603.4 A kcal/mole, respectively. Tabulations of Cp°, S°, - (G°-H°298)/T, H°-H°298, ?Hf°, ?Gf°, and log Kf are given to 1,200° K.

Jan 1, 1971

By W. P. Stroud

In this U.S. Bureau of Mines report, the conditions required for the direct reconstruction of a tomogram from observed line integrals are examined. Because of the limited access to the working faces in coal mines, the special case of access to only two opposite faces is emphasized. Classical matrix methods were used for small dimensional (2 by 2, 3 by 3, and 4 by 4) applications to determine the limitations and the requirements for a solution. The results for large (n by n) grids were then inferred and generalized from those of the smaller grids and matrices. Limited access tomography is found to be appropriate for in-seam hazard detection from seismic and microwave data, but it is shown that additional data must be added to obtain a direct solution.

Jan 1, 2010

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 Jon C. Volkwein

Advances in mining technology have enabled deeper seams of coal to be mined from the surface. Highwall mining is frequently used to mine areas at the perimeters of a surface mine when removal of the overburden becomes uneconomical or threatens environmentally sensitive surface features. At the same time, advances in materials and technology have enabled highwall mining of coal that create blind headings over 300 meters in length. Deeper surface mining and deeper highwall penetration depths have lead to more frequent encounters with methane gas. While this coal is remotely mined from the surface, underground ignitions of methane have propagated to the surface and injured miners. Methods described in this paper show how this hazard can be correctly monitored and controlled for auger type highwall mining machines. Research indicates that small quantities of gas liberated during mining migrate to the face, creating higher gas concentrations than would otherwise be expected. Using the same principles that cause the gas to migrate to the face, researchers have shown that inert gas introduced at the collar of the hole can inert the entire hole, thus ensuring safe conditions for mining.

By R. R. Sayers

The terms "sanitation and }\Vgienen are often used interchangeably, but it is more "' usual to apply ttsani tat ion'' to th environment or surroundings, and nr.ygieneto the iiiividual, The subject,. h9wever, is so broad that only a few of the phases of sanitation will be di.acusae in ·this paper, vmile the various Fsea of hyg:tene will be deferred for later consideration. One of the bes.t .iaf ini tions of sanitation that I have hearci was given by ur. L. L • Lumsden, of the U, S. Public Heal th Service, who state.d that "'sanitation is t-he c.oir .. 'Don-sens$ application of the principles of cleanliness,

Aug 1, 1922

By M. S. Seehra, R. S. Pandurangi

"Investigations of the infrared spectra of crystalline and amorphous silica particles of different sizes (0.05, 5, 10, 15, 30, 45, and 260 um) in the range of 400-4000 cm-1 using Fourier transform infrared/photoacoustic spectroscopy we reported. The change in the intensity I of the signal with porosity e of powders follows the e/(1 - e) dependence for strong bands and e dependence for weaker bands as pre¬dicted by the theory of McGovern of al. For strong bands, I also follows the empirical relation I ~ D-n, where D Is the particle diameter in cm and n = 0.34-0.42. The anomalous positive frequency dependence of I on the modulation fre¬quency f observed for the stronger bands in the 45-pm and 260-pm particles Is believed to result from saturation. Some observations on the effect of changing the background from (carbon black) powder to pellet are also made.INTRODUCTIONSince the publication of the Rosencwaig—Gersho (RG) theory on the photoacoustic effect in solids (1, 2), Fourier transform infrared/photoacoustic spectroscopy (FTIR/PAS) has become an important technique for obtaining the IR spectra of surfaces and materials in their natural state (1-12). In the one-dimensional RG theory, the incident radiation, modulated at frequency f, is absorbed by the material to a depth pp = 1/B (B = absorption coefficient), thus setting up temperature variations in the material. These variations heat the adjacent gas/solid interface leading to the pressure fluctuations of the gas above the sample, which in turn is detected by microphone as a PA signal. The thermal wave originating from no deeper than the thermal diffusion length(2k/npcf) 1/2 in the material contributes to the PA signal (here k, p, and c are respectively the thermal conductivity, density, and specific heat of the material). Since u2, can be varied by varying the experimental parameter f, depth pro¬filing by PAS is possible and a number of papers on this subject have appeared in recent years (2-10). Another im¬portant phenomenon is saturation which occurs when the material thickness 1> u> us (1-12).The original promise of PAS for use with powder samples, without the need to ""prepare"" samples as in FTIR spectros-copy, has not yet been fully realized because of several com¬plications. Theoretical works by Monchalin et al. (13) and McGovern et al (14) showed that the interstial gas in the voids of the powders can act as amplifier and that, for the same mass, a finer powder is expected to yield higher PA signal than a coarser powder. Although in a number of earlier studies (15-21) an increase of PA signal with decreasing particle size has been observed, a quantitative check on the equations developed by McGovern et al. (14) has not yet been made. It is necessary to understand the particle size effects in PAS if the promise of PAS for IR spectroscopy of powders is to be realized. In this paper, we report results of a detailed study on the PAS of silica powders for the particle size range of 0.05-260 um and compare the results with theory (14). We have also investigated the frequency dependence of the variousIR modes in these powders and show that the saturation phenomenon affects at least some of the observations. Some observations on the effects of pellet vs powder background are also reported (22-24). Details of these findings are presented and discussed in this paper."

Jan 1, 1990

By David Cooper, Susan Robertson, William Wiehagen, Launa Mallett, Charles Vaught, Joan Dickerson, Richard Conkle, ROBERT PETERS, Mike Brnich, Charles Urban

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. The videos on the DVD that accompany this guide can be shown at the beginning of training to give trainees an idea of what the job entails and related requirements. They can also be used within the training cycle (after the trainee has some experience in the job) to reinforce key points or as a trigger for eliciting questions about particularly difficult parts of the job. The video segments are meant to be visual models of good performance. They are designed to elicit discussion on good (lower risk) ways to do the job. In this context, they can be used very creatively at different times within the training cycle. The section on “Talking Points” offers a number of questions that can be used in the classroom to support and elaborate on certain aspects of the job duties. If the trainee has a fair amount of underground experience, some of the questions can also be used to support the pretraining assessment (i.e., skill check) of knowledge and skills. Likewise, some of the questions can also be used while teaching on the job to reinforce key points affecting safety, production, or maintenance. The section dealing with a mine’s roof control plan should be used at various times in the training cycle to make sure the trainee understands the plan and knows how to apply it in performing the job. The supplemental materials offer additional resources that can be used to support initial job training or follow-up. Learning continues well after an individual has been trained. The supplemental materials can help reinforce good operating skills and provide an opportunity for further discussion on better ways to do the job.

Jan 8, 2006

By M. R. Geer, H. F. Yancey

"INTRODUCTION The increased use of coal as pulverized fuel has focused attention on the grindability of coal and on the necessity of evaluating this property by a method suitable for use in the usual coal-testing laboratory. Without some knowledge of how various coals behave in the grinding operation, that is, how their use affects mill capacity and power requirements, the selection of coals for pulverized-fuel plants cannot be made on the same critical basis used in selecting coals for other types of burning equipment. The grindability of a coal, serves principally as an indication of the mill capacity attainable in grinding it - not as a direct index of the total cost of grinding. Although the grindability of coal may play a minor role at some plants, it is a decidedly important factor where pulverizer capacity limits the ability to carry high loads.Purpose Standardized tests for determining the grindability of coal are relatively new, so that the information now available on the grindability of various coals is limited in comparison, for example, with that available on proximate analyses. Published information is restricted to determinations on many important Eastern coals by the Fuel Engineering Co. of New York, 4/ a bulletin giving the results of numerous tests by the Babcock and Wilcox Co. 5/, and a comprehensive report on. Alabama coals by the Bureau of Mines. 6/This report presents the results of grindability tests of 34 samples of coals from Illinois, Kentucky, Pennsylvania, Utah, Virginia, Washington, West Virginia, and British Columbia at the Northwest Experiment Station of the Bureau of Mines, Seattle, Wash., in cooperation with the College of Mines of the University of Washington. In the future, as the laboratories of the Bureau make grindalility tests of other coals, additional reports will be issued."

Jul 1, 1938

By Gerald J. Joy, Paul J. Middendorf

This study examines the patterns and trends in noise exposure documented in data collected by Mine Safety and Health Administration inspectors at U.S. coal mines from 1987 through 2004. During this period, MSHA issued a new regulation on occupational noise exposure that changed the regulatory requirements and enforcement policies. The data were examined to identify potential impacts from these changes. The overall annual median noise dose declined 67% for surface coal mining and 24% for underground coal mining, and the reduction in each group accelerated after promulgation of the new noise rule. However, not all mining occupations experienced a decrease. The exposure reduction was accompanied by an increase of shift length as represented by dosimeter sample duration. For coal miners exposed above the permissible exposure level, use of hearing protection devices increased from 61% to 89% during this period. Participation of miners exposed at or above the action level in hearing conservation programs rapidly reached 86% following the effective date of the noise rule. Based on inspection data, the occupational noise regulation appears to be having a strong positive impact on hearing conservation by reducing exposures and increasing the use of hearing protection devices and medical surveillance. However the increase in shift duration and resulting reduction in recovery time may mitigate the gains somewhat.

By Craig S. Compton

The failure of the immediate roof or "roof skin" between installed primary and secundary roof supports causes hundreds of injuries and, on average one or two fatalities each year in U.S. underground coal mines. Conventional roof supports cannot cover enough roof area to adequately control these relatively small, but very dangerous rock falls. The 2006 Mine Safety and Health Administration (MSHA) accident database lists a total of 542 ground fall injuries, including 10 fatalities. An analysis of the database suggests that 434 of the injuries and three of the fatali­ties can be attributed to roof skin falls (See Figure 2). The key to controlling falls of the immediate roof or roof skin is maximizing the area of roof coverage ilnd confining these relatively small loose rocks. Roof screen offers maximum coverage of the immediate roof. Depending on the size and configuration of the screen panels, coverage of up to 100% of the roof area is possi­ble. Screen also offers a first line of defense for machine operators working in the face area by confining or deflecting small rocks that can come loose during mining or roof bolt installation. Figure 1 shows an example of the protection screen provides dur­ing bolt installation. Although the benefits of screen are well-known, mining com­panies in some areas of the U.S., mainly Northern Appalachia and the Illinois basin, are not convinced that roof screen is the best tool for dealing with roof skin control issues. The logistics of material handling, possible ergonomic injuries to workers, and the costs associated with installation are delaying the acceptance of screen as an on-cycle roof support tool. Other mines however, have concluded that installing roof screen can be cost-effective when compared to the cost of lost time accidents, training of replacement workers, or returning to already developed entries for the cleaning and rebolting process.

Jan 1, 2009

By E. H. Denny

The coal and metal mines of the United States furnish this country with a large part of the fuel and material necessary to support our industries and thus make possible the welfare and prosperity of our people and even the continuance of our present-day scale of civilization. Mining companies furnish material to industry with one general purpose in mind -- the making of a profit on their work. Efforts are being made successfully and continually to reduce operating costs, to increase production per man, and to perform work as far as possible mechanically and with more efficiency. These efforts are made primarily to reduce costs, to increase production, or to do both - in other words to make more profits or more certain profits. In the endeavor to reduce expense companies are considering more and more the factors which enter into costs of production, among them the factor of accidents and their cost. This paper endeavors to estimate the approximate cost of accidents to the mining industry in order to present the saving possible through accident reduction or elimination.

Jan 1, 1929

By G. R. Hopkins

A fifth successive record in fuel efficiency was established by the petroleum-refining industry in 1937, when the average heat requirement per barrel of crude oil run to stills was 554,000 3. t. u. compared with 597,000 3. t. u. in 1936. These amounts represent roughly the heat ob¬tainable from a tenth of a barrel of fuel oil (see fig. 1). Innumerable factors can influence heat consumption at rep aeries, but only a few are important enough to be subject to statistical measurement. Foremost of these is the ratio of runs to capacity, it being generally recognized that because the fuel demands for other than stills are comparatively inelastic, total heat requirements do not increase in direct proportion to crude runs. Thus, in 1937, crude runs of 1,183,440,000 barrels wore 11 percent higher than in 1930; the average operating ratio was 93 percent compared with 79 percent in 1936; but the total heat requirement increased only 4 percent, or from 639,149 billion 3. t. u. in 1936 to 663,966 billion 3. t. u. in 1937.

Jan 1, 1938