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By Janet Torma-Krajewski, Pauline Lewis, Paul Gust, Lisa Steiner, Kean Johnson

Ergonomics processes described in the literature have been associated mostly with manufacturing, financial, electronics, and office settings where working conditions tend to be rather constant and repetitive. The information presented in this document demonstrates, however, that an ergonomics process can also be implemented in a setting such as mining where working conditions frequently change and workers are periodically exposed to extreme weather conditions. This document describes how Bridger Coal Company implemented an ergonomics process at its Jim Bridger Mine from 2001 through 2004. The process developed by the Ergonomics Committee, the promotion of the process to management and employees, and the impacts of the process on working conditions at the mine are reviewed. Barriers overcome and lessons learned are also described. Quotes from Bridger Coal Company employees are included in the document to add a personal perspective. Other industries with working conditions similar to mining, such as construction and agriculture, may find this information useful.

Jan 9, 2006

Microstructural investigation has shown that grain splitting or deformation banding ( DB ) develops progressively with increasing strains during cold rolling. Of particular significance to simulating texture development in cold rolled BCC polycrystals is the operation of higher order slip systems other than 110 and, the occurrence of DB in the rolling plane since the latter allows a new relaxation of the shears. Deformation banding ( DB ) model includes grain subdivision in the rolling plane and applies the Relaxed Constraints ( RC ) mechanism for the other shears. An energy criterion for deciding whether deformation banding occurs or not has been postulated, referred to as Deformation Banding Criterion ( DBC ). This paper reports the results of the investigations into the effects of different slip systems, i.e., those based on 110, 112 and 123 slip planes and their combinations using RC, DB and DBC models, in developing simulated BCC rolling textures.

Jan 1, 1999

By Jianhang Hu, Li Yang, Yonggang Wei, Kongzhai Li

"In this paper, the pyrolysis of biomasses including bamboo, sawdust and walnut shell were performed in a tube furnace under temperatures between 400? and 600? to obtain biomass carbon, gas, and tar. Textural parameters analysis revealed the caloric value of biomass carbons between 32 MJ/kg and 34 MJ/kg. It also indicated that the surface of biomass carbon consists of mesopore and macropore structures. By using GC analysis, it was determined the main ingredients of pyrolysis gas are CO, H2, CO2, CH4, C2H4 and C2H6. Calculation states that the density of pyrolysis gas is roughly between 1.0 kg/m3 and 1.7 kg/m3, while the calorific value of pyrolysis gas is between 12000 kJ/m3 and 16500 kJ/m3, illustrating that pyrolysis gas is a median gas. The calorific value of biomass tar was found to be between 32 MJ/kg and 34 MJ/kg, with more than 80 compounds in the biomass tar identified by GC-MS method.IntroductionBiomass as a renewable source is the world's largest and most sustainable energy resource [1].The conversion of biomass has the potential to be a renewable and carbon neutral method of producing fuels and chemicals [2-4]. Pyrolysis is a thermo-chemical process defined as applying heat to degrade biomass in an inert atmosphere. It transforms unstable biomass and other organic materials into biomass carbon, gas, and tar [5]. Biomass carbon can be stored or transported much easier as compared to parent biomass or be converted to value added products such as activated carbons[6]; gas is a relatively low-energy-density fuel; tar can be considered as a source of useful chemicals[7].The characterization of biomass pyrolysis will lead to its increased understanding and utilization as a source of solid, liquid and gaseous products which can be used as fuels and petrochemical feedstock[8,9].In recent years, many researchers studied the effect of temperature on biomass pyrolysis product distribution characteristics in a variety of pyrolysis reactor[10]. Ramin Azargohar's paper [11] presents the results of characterization for biomass and investigates the effects of pyrolysis temperature on the pyrolysis products obtained by fast pyrolysis of four different types of biomass."

Jan 1, 2014

By Richard H. Spencer, Thomas E. Doerfler, Robert L. Lagace, James M. Dobbie, William S. Hawes

This report assesses the expected detectability, on the surface above mines, of electromagnetic signals produced in the frequency band of 630 to 3030 Hz by a rescue transmitter activated by miners trapped underground. This assessment is based on a statistical analysis of experimental signal and noise data taken at a representative sample of coal mine sites well distributed over the United States underground coal fields. Regression analyses are performed to characterize the signal transmission behavior of overburdens as a function of depth and frequency. The predicted signal behavior is then combined with experimentally based distributions of the background noise, and aural detection characteristics of signals in noise, to generate curves of the expected probability of detection for trapped miner signals versus overburden depth and operating frequency. The implications of these results, and associated recommendations, are presented regarding the detectability of trapped miners, sensitivity analyses and confirmatory tests, and operational utilization considerations for the trapped miners and the search and rescue team on the surface.

Jan 7, 1980

By K McLeod

{Figure 1} The Placer Dome-Western Areas Joint Venture?s South Deep Twin Shaft Complex, has been planned and dreamt of for nearly 20 years. [ ] The gold reserve at the bottom of these shafts is one of the largest single intact gold deposits remaining in the world today, containing an estimated 57 million ounces. This is about the size of the fictitious reserve created by inventive prospectors for the infamous BREEX scam in Kalimantan about ten years ago and about the size of the reserve Harmony claims as its own in it?s current hostile takeover bid for Gold Fields. So it is certainly of the magnitude that dreams are made of. [ ] {Figure 2} The unique orebody lies in a continuous, highly concentrated, thick deposit, an estimated twelve kilometres along dip and a two kilometre wide strike. Due to the thickness of some sections of the reef, up to 60 metres in places, bulk mining methods will be required for it?s extraction. [ ] {Figure 3} The twin shaft system comprises a main shaft which had an initial design depth of 2765m and a ventilation shaft of 2760m, making them the world?s deepest to be sunk in a single lift. The shafts were

Jan 1, 2005

By E. Baliktsis

We have searched and analyzed several modern technologies aiming at the best applications of environmental management, the studying of quarrying ? mining as well as the excavation sites ? utilization ? rehabilitation. We have used long-range reflectorless laser surveying systems, so as to achieve the fastest and most accurate surveying of the extractive work sites. We also used them, in order to collect field data, measure distances, surveying monitoring stations and environmental parameters ? data. Furthermore these systems can make the field work quite faster, more reliable and credible and have low cost in collecting data even in dangerous and non-approachable areas. We have used and processed on the field data in G.I.S. applications, in order to create 2-D and 3-D digital ground models. These G.I.S. applications present the existing relief and the management of the final stage of the area. The suggested techniques and works needed, for reclamation and utilization of the areas, could be tried, evaluated and well presented. The evolution and utilization of these ?smart? modern tools for the effective environmental management of quarrying ? mining ? extractive activity sites, will be presented by using case histories from the Hellenic territory.

Jan 1, 2002

By R. Hogg

Experimental studies of the axial distribution of particles along dry ball mills are described. The results, for mills ranging in diameter from about 10 cm to 1 meter and operated in both the batch and continuous modes, indicate a consistent pattern of significant migration of particles away from the ends of the mill. In some, but less frequent, cases axial migration of the grinding media is also observed. Analysis of the data suggests that particle migration results from end-effects which extend for a distance of about one mill diameter along its length. End-wall roughness appears to play a significant role in the particle migration phenomenon. Media migration is generally associated with continuous mills operating at relatively high powder flow rates.

Jan 1, 1994

By Paul Kunze

We have been told many times by legal folks and insurance types about the importance of producing accurate blast reports should you ever get dragged into court. In that venue the investigators will look at the information regarding product type and quantity, it’s distribution among the holes, and delay information in order to arrive at some judgement regarding vibrations or other blast induced phenomena

Jan 1, 2003

By Vasile Murariu, William Pate, John Herbst, Dilek Alkac

"Multiphysics models are essentially first principles models capable of providing very accurate micro scale predictions. The computational requirements for Multiphysics Models are extensive, precluding their direct use for flowsheet simulations. Population balance models get their form from theory but the model parameters have to be provided from experiments. The prediction errors for the population balance models are typically significantly higher than those for the Multiphysics Models but the computational effort for Population Balance Models is typically much less than that for the Multiphysics models. The hybrid model described here takes advantage of the strengths of each of the two primary model types and minimizing the weaknesses of each. The Multiphysics Model is used to perform high accuracy "experiments" that are difficult or impossible to conduct in laboratories or plants. The results of these experiments are combined with standard laboratory or plant data to parameterize and further enhance the Population Balance portion of the hybrid model. The creation of a useful Hybrid Model is demonstrated for a MP1000 secondary crusher. The validation of the hybrid crusher model is also presented. Finally the use of the Hybrid Model is illustrated in a full comminution flowsheet simulator."

Jan 1, 2014

By D. C. Foote

MR. FOOTE: This paper deals with blasting and mechanical loading. The Union Pacific Coal Company does all of its blasting with permissible powder and electric shooting, but this paper deals principally with blasting in connection with mechanical loading. With the introduction of mechanical loading into the coal fields of southern Wyoming one of the main problems to be taken into consideration was the drilling and blasting of the coal. The methods used in blasting coal for hand loading were found to be ill adapted to the mechanical practice, so numerous tests were conducted from time to time to determine a system or systems whereby the coal might be blasted in a form to be easily handled by the loading units. The general practice in blasting coal for hand loading, for example in a room 24 feet wide and seven feet high with an undercut of seven feet, would be to shoot one or two strong breaking shots in the center and one on each rib. While much of the cut would be blasted down in good lump, some coal would be left hanging at the back and ribs. With hand loading, the miners would have time to pull this coal down with a pick between cars and eventually would clean up the place ready for the cutting machine. The loading machine, however, cannot get this coal down and its operation would be delayed while the men were doing the necessary pick work.

Jan 1, 1929

By Shiou-Chuan Sun

The froth flotation of coal, differing greatly from that of most minerals1-5, is not improved but rather impaired by temperatures higher than room temperature6-10 This phenomenon has long taunted us for an explanation. Gayle and Associates 8,9 reported the lack of relationship between their contact angle measurements and their flotation of American coals under various temperatures. Bailey and Whelan6 stated that the viscosity of flotation reagents, offering some clue for their flotation of British coals at low temperatures, could not be put forward as an explanation either in whole or in part for the effect of temperatures on coal-flotation. In this paper, a froth hypothesis is proposed to explain the flotation behavior of coals under various pulp temperatures. Test work involved the flotation of coals and the frothing of reagents.

Jan 1, 1966

By C. R. Wohrman

A MELT of pure electrolytic iron with about 0.4 per cent. sulfur and 7 per cent. manganese was prepared in connection with a study of inclusions in iron. The alloy darkened rapidly when etched with a 10 per cent. alcoholic solution of nitric acid, and microscopic examination revealed the presence of a semimartensitic, semi-Widmanstättian structure (Figs. 1 and 2) closely resembling the structures found by Benedicks in his artificially prepared "meteoric iron." 1 The structures found by Benedicks were readily explained by the presence in his alloy of the two well known iron-nickel solid solutions, taenite and kamacite, and of their eutectoid (?) aggregate, plessite. By analogy, one would infer the existence of similar phases in the iron-manganese alloy just described, such as inference being strengthened by the similarity displayed in many ways by nickel and manganese in their effects on iron. IRON-MANGANESE ALLOTS ARE REGARDED AS HOMOGENEOUS Heterogeneity of iron-manganese alloys has not been recognized heretofore, judging from the data of standard metallographic books and those of original papers. In fact, iron and manganese are quite generally regarded as completely miscible in the solid state. Dr. Rosenhain,2 for example, writes: Alloys of group (a), of which those of gold-silver, iron-manganese, and copper-nickel are examples, when allowed to crystallize sufficiently slowly to attain their condition of final equilibrium, present a microstructure exactly similar to that of a pure metal-the homogeneous character of the molten solution is in that case so completely maintained that the microscope cannot detect the presence of any second constituent.

Jan 1, 1927

By Quintin A. Aune

This report presents the results of a field and laboratory study by the Federal Bureau of Mines, in cooperation with the California Division of Mines, of the swelling-type bentonite deposits in the Vallecitos area in San Benito County, Calif. The purpose of the study was to learn if these large deposits contain bentonite of sufficient quality and quantity to be of economic value as an oil-well drilling mud additive. Large amounts of bentonitic clays are used by the petroleum industry as well as the steel industry in California. Additional amounts may be required in the near future as a concrete or earth-fill admixture in constructing dams and canals in the California Central Valley. Depletion of some local clay deposits and loss of others to military installation areas have given new emphasis to the need for developing new bentonite deposits in California.

Jan 1, 1959

By Marcus A. Grossman

THE institute has established this lectureship to honor the memory of a great American metallurgist, one whose fame has continued long after his passing. As one scientist recently stated it," All metallurgical texts gradually become outdated and outmoded, except those of the great Henry Marion Howe." It seems fitting, then, that, once every year, we should review, in his honor, some aspects of the science in which he was such a distinguished leader, and also discuss any new data that may help to clarify our concepts. It is my privilege, for which indeed I express the deepest appreciation to this Institute, to offer for consideration a few thoughts on the toughness and fracture of hardened steels. Before proceeding to the data, I wish to express my great indebtedness to many associates whose stimulating discussions, generous contributions of data and cooperation in experiments are gratefully acknowledged. (But I wish to absolve them of any blame that may arise from the way in which their discussions and data have been used!) First, Dr. Edgar C. Bain, Vice President, Carnegie-Illinois Steel Corporation, whose amiable but merciless criticisms and always constructive and thoughtful suggestions help unfailingly to guard against pitfalls. Then to associates at Gary Steel Works, especially Mr. H. B. Wishart, Mr. W. K. Smith and Mr. V. Elliott, for great assistance in securing data. Also to Col. C. H. Greenall, Director of Laboratories, Frankford Arsenal, and his metallurgical staff, including Messrs. J. K. Desmond, H. Markus, D. F. Armiento, H. Rosenthal and Henry George, for numerous data and illustrations. Further to Dr. J. R. Low and Dr. M. Asimow, for helpful discussions of effects of states of stress during deformation and rupture, to Mr. J. M. Hodge for discussions and data, to the staff of the U. S. Steel Corporation Research Laboratory for advice and data, and to the Metallurgical Staff at Duquesne Steel Works. The individual acknowledgments will also be found under illustrations. Acknowledgment is also due to Mr. S. C. Snyder for incredibly meticulous scrutiny of manuscript. To all of these, grateful thanks.

Jan 1, 1946

By Forest J. Sur

"This report describes an exploratory project conducted by the Bureau of Mines on a fluorite deposit near Vado, N. Mex. Results of trenching are given. Together with analyses made upon samples of the ore. The Federal Geological Survey3/ completed a preliminary geologic study and mapped the deposit during the summer of 1944. A Bureau engineer examined the deposit in August 1944. As a result of these investigations, it was concluded that the deposit contained substantial inferred ore reserves. Exploratory work was recommended to obtain information that might possibly lead to production from the property. Assistance was given the Bureau by the Geological Survey.A gasoline-powered air compressor, other equipment, and supplies were delivered to the property from January 20 to 25, 1943. Trenching began under the direction of a Bureau of Mines engineer on January 25, 1947, and ended on March 15, 1945. The results of trenching and sampling form he basis of this report.In its program of exploration 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 national security and economy. IT is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, R.G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervisions of Dr. R. S. Dean, assistant director."

Sep 1, 1946

By Luis Ramirez Grados

El presente texto examina los problemas de diseño que se presentan en el sistema de minado subterráneo debido a su interrelación con los variados escenarios geológicos. Para ello, se cita el ejemplo del acarreo de desmonte y mineral de la Estación de Carguío H-2 del Nv. 2430 de la Rampa RNG 92442 @ -15% hacia el echadero de desmonte y la Tolva de Mineral de la Planta Concentradora en superficie Nv. 2765, donde el sistema de acarreo fue modelado usando simulación, la cual fue utilizada para ver la rentabilidad del sistema scooptram-volquete.

Sep 14, 2009

By H. E. Wheeler

The work described was carried out during 1917 and 1918 at the testing laboratory of Watertown Arsenal at the instigation of the Nitrate Division and later with the concurrence of the Cannon Section of the Ordnance Department, U. 8. A. The experiments follow three principal lines of work: First, the effect of nitrogen under pressure on steel containers of various compositions at a red heat; second, the effect of decomposing ammonia on various alloy steels, iron, and non-ferrous alloys; third, a new theory of the erosion of guns in respect to the effect of nitrogen in steel. Part I In the Haber process for the manufacture of ammonia from its elcnlents, it is necessary to have nitrogen and hydrogen of 1500 lb. per sq. in. (105.5 kg. per sq. cm.) at a temperature of 500 to 600' C. The steel containers for these gases gave trouble by failing without apparent cause. When the General Chemical Co. began to develop its method for the production of ammonia, it experienced the same difficulty and, knowing that the Haber process had solved the difficulty by the use of alloy steels, it made several small steel bottles of different compositions and kept them filled with these gases at this pressure and temperature until they failed. The time of service varied from a few days, for the plain steel casting, to two years for a chrome-vanadium forging. Four of these steel bottles were sent to this laboratory for investigation; they were a plain carbon-steel forging, a nickel-stee1 forging, a chrome-vanadium steel forging, and a chrome-steel forging. The time of service was as follows: plain carbon steel, 4 mo.; nickel steel, 6 mo.; chrome-vanadium steel, over 2 yr.; chrome steel, 4 mo. When these containers were cut open and the cross-section surface polished, they showed an inside zone with a different luster from the rest of the metal. Upon etching, this zone was almost unaffected while the rest of the steel etched normally.

Jan 1, 1922

By H. W. McQuaid, E. W. Ehn

It is usually assumed that chemical specifications are sufficient for steel to be used for case carburizing, and if the steel analyzes within the ordinary limits specified for steel for this purpose, no difficulty traceable to the steel used should be encountered in obtaining satisfactory results in the case carburizing and hardening. Much work has been done to determine the effect of various alloying elements on the rate of carbon penetration, etc. but, to our knowledge, little if anything has been published in regard to the effeet of the quality of the steel on the final results in the hardening of case-carburized steel parts. The writers believe that the structure of the case both before and after quenching is greatly affected by the actual condition of the steel itself as made, and that for good results in the case-carburizing and hardening departments, the steel should be of the best possible quality as regards non-metallic impurities. It is the purpose of this paper to prove that the presence of excess dissolved oxides in the steel, as made in the melting furnace, affects permanently the results obtained in carburizing and hardening and that it is possible that the presence of dissolved oxide call result in total unfit-ness of low-carbon steel for case hardening purposes. When races and rolls for roller bearings are made from a low-carbon steel, case carburized and hardened, it is of primary importance that the results of this treatment be of the highest quality. It is necessary, therefore, that in the case-carburizing work each detail be rigorously checked to avoid any defects which would cause the loss of much time and material. The case carburizing with which this paper deals was done in under-fired oil furnaces. The temperature of each furnace is controlled by means of a platinum platinum-rhodium thermocouple, in connection with a potentiometer indicator and potentiometer recorder. The temperature of each furnace is registered every 15 min. by an operator, who is continually checked by the automatic recorders.

Jan 1, 1922

By F. B. Tough, B. H. Scott

"Petroleum engineering is a comparatively new branch of engineering, with which few people, even petroleum operators and mining engineers, are thoroughly familiar. Petroleum engineers are responsible for the accurate keeping of well logs and all pertinent data upon formations encountered, for the careful analysis of such information, and recommendations as to most suitable places for drilling, for detailed study of methods of drilling, casing, and so on in order to obtain maximum production for a minimum cost.The Bureau of Hines has from time to time carried on work in all branches of petroleum engineering in the various fields of the United States. Such work is also being carried on extensively by the California State Mining Bureau, which has in its employ a number of men who have had, besides their technical training, actual experience in oil field work. This is about the only state at the present time which is carrying on this work in a definite way. It has therefore been the practice of the employees of the Bureau of Mines to go to other states and give such advice and assistance as might prove of value in development work and in prolonging the production of the fields."

Jan 1, 1920

By D. W. Park

Longwall Strata Control and Maintenance System (LoSCoMS) is a software and data communication system developed at the University of Alabama. This system integrates real-time shield monitoring, data presentation, analysis and forecasting of forthcoming events. The main objective of this system is to provide stability information on longwall panels including excessive shield load, low setting pressure, leg leakage and poor shield performance, eminent maintenance problems, etc. Analyses of various mining and geological parameters were also performed to determine past and present roof characteristics and to forecast roof loading patterns for the following mining cycles, next periodic weighting, etc. A local coal mine in the Warrior Coal Basin has adopted this system to provide daily evaluation of ground stability and maintenance problems of their longwall panels. Two years of experience with this system is covered in this paper.

Jan 1, 1998