Search Documents

By J. W. Paul

The United States Bureau of Mines has made a study of roof control in 68 mines operating in the Pittsburgh coal bed in Pennsylvania, West Virginia, and Ohio. In making these studies, much information was also obtained on various exact methods of development and pillar extraction as practiced by this large group of mines. It is proposed in this paper to describe these methods, by which this group of mines in 1931, a year of reduced industrial activity, produced 28,123,000 tons of bituminous coal - 7.4 percent of the national production for the same year and an amount equal to the combined production of the coal mired in the States of Alabama, Colorado, New Mexico, Utah, and Wyoming. The results of these studies, insofar as they pertain to the prevention of injuries from falls of roof, have been published by the Bureau of Mines. In this paper only a few mines typical of each system will be described; however, should the reader be interested in other details with respect to these mines, he may refer to the following publications: T.P. 522, 1932, 43 pp. Falls of roof and coal in mines operating in the Pittsburgh coal bed in Marion and Monongalia Counties, W. Va., by J. W. Paul and J. N. Geyer.- A study of nine mines in these two counties of northern West Virginia.

Jan 1, 1935

Certain information contained herein regarding Champion Minerals Inc., including management?s assessment of future plans and operations, may constitute forward-looking statements under applicable securities law and necessarily involve risks, including but not limited to risks associated with mining exploration, operating costs, production costs, volatility of share prices, currency fluctuations, imprecision of resource and reserve estimates, environmental risks and ability to access sufficient capital from internal and external sources. As a consequence, actual results may differ materially from those anticipated in any forward looking statements. Plans, intentions or expectations disclosed in any forward-looking statements or information should not be read as guarantees of future results or events, and will not necessarily be accurate indications of whether or when or by which such results or events will be achieved. Except as required by law, Champion Minerals Inc., expressly disclaims any intention and undertakes no obligation to update any forward looking statements or information as conditions change. The historical mineral resources mentioned are strictly historical in nature and are non-compliant to National Instrument 43-101 mineral resources and mineral reserves standards, and should therefore not be relied upon. A qualified person has not done sufficient work to upgrade or classify the historical mineral resources as current National Instrument NI-43-101 compliant.

May 1, 2011

Two miners were fatally injured when a pillar bump occurred during retreat mining in a southern West Virginia coal mine. The mine was operating in the Eagle seam with overmining in the No. 2 Gas and Powellton seams. A coal bump is defined as a sudden and violent failure of coal caused by the release of stored strain energy in the pillar. While significant strides have been made by academia, industry, and regulatory agencies to better understand bump conditions and mitigation techniques, coal bumps represent a long standing, highly site-specific engineering problem in which the exact failure mechanism(s) is not clearly understood.

Jan 7, 2020

By James S. Graham

Foundation pile driving hammers used in New York City in the past 100 years have been drop, steam, compressed air, diesel, and hydraulic. In 1992, the first hydraulic hammer in the New York City area was purchased by Norwalk Marine Contractors, Inc. from Junttan in Finland. It was bought because of its variable energy and ease of mobilization, not because of its higher transferred energy. Heller and Johnsen engineers instrumented hydraulic hammers on nine jobs. The measured transferred energy for the nine jobs was found to average approximately 80 percent. There is no clear consensus regarding the reasons for the hydraulic hammer being more efficient in delivering energy to the pile as compared to single-acting steam/air impact hammers. To minimize pile damage during installation, and to minimize footage overruns, an up-to-date version of the wave equation software that includes an efficiency value of 0.95 for hydraulic hammers is now used.

Jan 1, 2000

By Kenneth L. Whitehead

After many years of research, the occurrence of pneumoconiosis, black lung disease, among miners has been related to the mass of respirable coal dust to which mining personnel have been exposed. Congress passed Public Law No. 91-173 in 1969, which limited the dust concentration of respirable dust allowed in the mine working areas to 2.0 mg /M3 as of December 31, 1972. As a result of these restrictions, much work has been done in determining methods of either eliminating or suppressing respirable dust. The purpose of this project is to determine the state-of-the-art in continuous mining machine bit technology, particularly with regard to dust production.

Jan 1, 1973

By William P. Harris

The Lincoln Terminal System is described as a device with the capability to deliver technical information, monitor student performance, and assure learning in industrial training. An experimental unit, the LTS-3S, was constructed and delivered to the Bureau of Mines with appropriate lesson material for a test of feasibility and acceptability of this form of training in the mining environment. Operations were conducted at two mine maintenance schools. The overall results were that (1) there was a substantial improvement between tests before and after self-training on the LTS, (2) students found this an acceptable way to learn, and (3) reaction by training personnel and supervisors was favorable toward the feasibility and advantages of using the LTS in the mining environment. Transfer of the LTS to industry depends on availability of reliable units and adequate lesson material. The requirements for authors of training materials were established based on advice from mine training experts, formal analysis of lesson development procedures, and experience from efforts in lesson development at Lincoln Laboratory-It was concluded that experienced mine training instructors were best qualified to proceed effectively and economically to format instructional material for the LTS, if supported by well-designed facilities and services. Discussion with mining experts confirmed the desirability of generating training materials and delivering instruction at distributed locations to meet local training needs and in direct support of industrial operations.

Jan 1, 1975

By Hiren J. Shah

The urban environment and geology create unique challenges for design and construction of deep foundations. The effect of these is prominently experienced in New York City. Three such project case histories are presented in this paper. The first project is a multi-use development. Relatively unusual glacial geology was observed at the site during the subsurface investigation phase. This played an important role in the selection of deep foundations as well as during construction. The design and construction aspects of the pile foundations, settlement estimates, a pile drive test program during design, piling equipment and production pile installation are discussed herein. A relatively smaller project is the second case history. A combination of drilled and driven deep foundations was employed in one area of the project due to its unique conditions. In another area of the project, an addition to a structure required the use of supplemental foundations to resist new additional loading. Tight space and load sharing with the existing foundations were important considerations in the design and construction. Finite element modeling of the existing and completed structure was performed which was an interesting aspect of the project. The third project case history involves a very large multi-billion dollar project in which various different types of deep foundation elements were used. The aspects requiring the use of such a variety of types and sizes of deep foundation elements included: geologic conditions, re-use of existing foundations, protection of adjacent infrastructure, construction staging, restricted space, loads, deep excavations, cost and schedule.

Jan 1, 2011

By Tingkan Lu

To understand the reinforcing mechanisms of the fully grouted resin bolt and clarify its performance in weak roof strata, the field monitoring investigation using instrumented bolts has been conducted in a coal mine. The total time of monitoring was around ten months. In the first 8 month period, the rock bolt performance relates to the initial development of the gateroad and subsequent time dependent strata response. After 8 months, the rock bolt performance relates to the effect of the approaching longwall mining operation, up to the point where the measuring station was destroyed due to the mining operation.

Jan 1, 1998

By G. S. Scott

In the course of the Bureau of Mines investigation relative to the causes, behavior, and control f anthracite-mine fires, attention was directed toward the correlation between the temperature of oxidation and the gaseous oxidation products in the range of temperatures between 100° and 350°C4/ These tests, made on a high-grade anthracite to determine the amount of oxygen consumed and the amounts of carbon dioxide, carbon monoxide, hydrogen and methane evolved when air was passed through samples of the anthracite at various elevated temperatures, showed that the gases evolved and their relative proportions vary with temperature, constitute a means for determining the probable temperature of the anthracite, and thus permit detection of incipient heating before a dangerous fire hazard exists. As the relationships mentioned are affected somewhat by the amount of previous oxidation of the coal, it was deemed desirable to know to what extent they might vary owing to this cause. It was also considered desirable to have a means for estimating the extent of oxidation from the gas analysis, as this would permit a more accurate estimate of probable temperature. Finally, it seemed desirable to know how much the composition of coal might vary over an extended period of oxidation, since this was previously suggested5/ as a possible means for estimating the probable maximum oxidation temperature to which a sample of coal had been subjected.

Jan 1, 1940

By Virgil Marple

In the summer of 1979 the University of Minnesota Mobile Laboratory (UMML), designed for the analysis of airborne particles and gases was used to study fugitive dust from an open pit coal mine. The analysis consisted of determining the particle size distribution and concentration of dust from various mining operations, such as blasting, draglines, loading, roadways and bottom scrapers. For some operations the particles size distribution and concentrations were determined at varying distrances. Details of the dust concentration within the plumes as the plume passed the UMML were measured with an optical particle counter. For line sources, such as roadways this enabled the calculation of the particle flux at the sampling location. In addition to the standard instruments associated with the UMML, the applicability of some new instruments were investigated. These included a uniform deposit cascade impactor and a flux meter. Finally, a technique in identifying plume origins which utilized elemental X-ray flourescence analysis of filter samples was shown to be effective.

Jan 1, 1980

The mining industry worldwide is currently facing a significant restructuring process. In most underground mines, widespread mechanization of the mining processes increases production while reducing staff numbers. At the same time, mining depths as well as the lateral spread of the mine workings are increasing. This ever-changing mining environment requires sophisticated solutions for the design and operation of underground mines. In fact, a reduced number of mining engineers is taking responsibility for everincreasing mine operations. This applies not only to the excavation of the minerals, but also to all other aspects of the mining operation, including health and safety, disaster management, and mine rescue organization. Most mining engineering graduates entering the industry lack experience in mine emergency management. Young engineer trainees must learn mine emergency management and rescue work in addition to their normal training experience on the job. Often, and unfortunately, emergency and rescue training at different mining companies is not carried out to the highest level and standard and with the best possible training outcomes. The tasks and challenges a young engineer faces while being trained in a new position do not leave much room for additional training in mine rescue and emergency management. At the same time, experienced, ?old hands? are retiring and cannot easily be replaced due to limited graduation numbers. Strategies are being developed at mining universities worldwide to train mining engineering students in handling mine emergency situations and to provide hands-on experience for managing potential accident and disaster scenarios underground. Two of these strategies, from the USA and from Central Europe, are presented in this paper. These specific strategies have to be seen under special consideration of the local and regional boundary conditions, but might serve as case studies for mining schools and universities in other countries.

Jan 1, 2014

By N. Henderson, J. Weyer, J. F. Brune

"The mining industry worldwide is currently facing a significant restructuring process. In most underground mines, widespread mechanization of the mining processes increases production while reducing staff numbers. At the same time, mining depths as well as the lateral spread of the mine workings are increasing. This ever-changing mining environment requires sophisticated solutions for the design and operation of underground mines. In fact, a reduced number of mining engineers is taking responsibility for everincreasing mine operations. This applies not only to the excavation of the minerals, but also to all other aspects of the mining operation, including health and safety, disaster management, and mine rescue organization.Most mining engineering graduates entering the industry lack experience in mine emergency management. Young engineer trainees must learn mine emergency management and rescue work in addition to their normal training experience on the job. Often, and unfortunately, emergency and rescue training at different mining companies is not carried out to the highest level and standard and with the best possible training outcomes. The tasks and challenges a young engineer faces while being trained in a new position do not leave much room for additional training in mine rescue and emergency management. At the same time, experienced, ’old hands’ are retiring and cannot easily be replaced due to limited graduation numbers.Strategies are being developed at mining universities worldwide to train mining engineering students in handling mine emergency situations and to provide hands-on experience for managing potential accident and disaster scenarios underground. Two of these strategies, from the USA and from Central Europe, are presented in this paper. These specific strategies have to be seen under special consideration of the local and regional boundary conditions, but might serve as case studies for mining schools and universities in other countries."

Jan 1, 2014

By Rafael de Araujo Silva

As ligas ß-Ti têm sido consideradas materiais com potencial para armazenagem de hidrogênio no estado sólido. A adição de elementos de liga estabilizadores da fase ß, tal como o Nb, retém esta fase metaestável em temperatura ambiente. Neste trabalho a liga Ti-40Nb (at.%) foi produzida via fusão a arco e suas características microestruturais foram caracterizadas visando avaliar os efeitos da aplicação da deformação plástica severa (SPD, severe plastic deformation) e da hidrogenação. A laminação a frio sob atmosfera de Argônio foi a técnica de SPD escolhida. Os resultados principais mostraram que é possível hidrogenar a liga fundida Ti-40Nb em temperatura ambiente após laminação a frio. Os efeitos da deformação plástica severa na microestrutura da liga, como a introdução de discordâncias, foram importantes para o aperfeiçoamento da cinética de absorção em temperatura ambiente (25 °C). Após a dessorção da fase hidreto (CFC) a microestrutura volta a ser constituída pelas fases ? (CCC) e ?” (ortorrômbica).

Aug 17, 2017

By E. A. Lowe, J. W. Smith, C. W. Overton

"The operations of Bethlehem Copper are situated in the south-central interior of British Columbia at an elevation of 4900 feet above sea level. Main road and rail transportation systems pass through Ashcroft in the Thompson Valley, which is 28 miles by road from the minesite. The operation was the first low-grade open-pit porphyry copper mine in British Columbia.The minerals are chiefly chalcopytite and bornite, while the rock is principally feldspar and quartz. In the outer fringes of the orebodies some pyrite is present. Average grade of mill feed is 0.55% copper.History of Milling Operations Production commenced in December 1962 at a rate of 3,000 tpd in a plant that comprised two-stage crushing followed by rod and ball milling. Production ratings were increased to 6,000, 10,000 and 12,000 tpd by the addition of a further stage of crushing and more rod and ball mills. When the last expansion was completed tonnage throughput exceeded the 12,000 ton designed rate and was stabilized at 15,500 tpd.However, recovery did not meet expectations at the expanded rate because of coarse flotation feed. Capacity in the rod mill circuits exceeded the subsequent fine grinding capacity, resulting in poor liberation. Studies were initiated to improve recovery without decreasing throughput.Description of Operation Prior to Pebble Milling Crushing with primary, secondary and a closed tertiary stage proceeds at a scheduled 20.5 shifts per week. Fine ore screened on 1/2"" x 4"" apertures is stored in a 30,000-ton bin ahead of two 12.5' x 15' rod mills. Rod mill discharge joins secondary ball mill (one 10.5' x 14' and one 11' x 14') discharge for classification in a single 50"" cyclone which closes the secondary mills. Overflow from this cyclone is split between three third-stage ball mill-pump-cyclone circuits (two 11' x 14' and one 12.5' x 15'). Prior to addition of the two pebble mills the flotation feed was produced by this three-stage grinding system. Grinding criteria are shown in Table I."

Jan 1, 1975

By A. B. Hooker

Nineteen of the installations were on rental contracts 1.L."'1der whtch the lamps belong to the lamp company and are rented by t.½em to the mine operatj.nt; company. · The other nine installations had been upon an O\Vnership-rental basis, by which the lamps had become the property of the renter at the end of 5 years. Five of t.11e rentec installations were en a special contract calling for a guaranteed light output. These contr2.cts were based upon certified . initial performance, with the provision that the lamps be replaced whenever periodic tests of fully charged lamps, taken at random from t..h.e charge racks, showed a light output of less than 80 percent of the certified performance.

Jan 1, 1942

By A. M. Keenan, R. H. Carpenter

Geologic faults have always been a plague to the mining industry, and have often reduced a mining venture from a profitable to a marginal operation, and even at times have forced companies to liquidation or bankruptcy. The use of geology as an economic tool in coal mining is not generally recognized, particularly in coal deposits which are horizontal or essentially flat-lying, in which faulting might not be prevalent. However in pitching coal seams, the existence of faults is considered an inherent challenge, as the inclination of the seam or seams per se, is a product of geologic disturbance. The problems of faults are a constant challenge to the management of the Thompson Creek Coal and Coke Corp. in their operations in Pitkin County, Colorado, where high grade medium volatile coking coal is mined. The background for this paper has been provided by the experiences of these operations, in overcoming the effects of faults in mining, and resolving the fault structures. The properties of the Thompson Creek Coal and Coke Corp. are located in central Colorado, 13 miles southwest of Carbondale, Colorado, a tow] on the main highway between Glenwood Springs and Aspen, Fig. 1. The elevation at the mine portals is approximately 8000 feet: there is a relief of some 2.000 feet to the adjacent ridges rising away from the [nine portals. 'The entire present production of these properties totaling 180.000 tons of clean coal per year is trucked to the railhead at Carbondale, Colorado, from whence it is shipped to the Geneva Steel Plant at Provo, Utah. The properties were initially opened in September 1952. A total of 125 men are currently employed with the production conting from the Number 1 and 3 Mines, and development workings of the Number 2 and 5 Mines respectively. While the No. 2 Vine was opened in 1953 prior to No, 3 Mine, the encountering of faults without sufficient development work accomplished to sustain production, necessitated the diversion of manpower to the other [nines for economic considerations. GEOLOGY '1-he productive coal seams occur in the Mesaverde formation of Late Cretaceous age which outcrop along the eastern edge of the Piance Creek Basin from the Grand Hogback, a part of the southwestern flank of the White River Uplift north of Glenwood Springs, southward through the 'Thompson Creek area and the

Jan 1, 1961

By Chen Song

Keywords: Co3O4, Cobalt Compounds, Morphology, Urea, Homogeneous Precipitation Depending on experimental condition, precipitation from cobalt nitrate and chloride solution in the presence of urea yield dispersed cobalt compounds with different chemical compositions and morphologies. The effects of concentration of cobalt solution and urea, agitation, on precipitation morphology were investigated experimentally. Generally in closed systems the particles are identified as cobalt (II) basic carbonate with needle type shape. In open system, spherical and plate-like precipitations of cobalt (II) basic cyanate are formed. The chemical formula of cobalt compounds was confirmed. They are CoII,III(OH)0.83(CO3)0.49 Ay?0.14 H2O (in tightly-capped reactor: A stands for NO3?, Cl?; y[A]molecular weight < 12.9) and CoII,III(OH)0.83(NCO)XAy?0.14 H2O. (in open reactor A stands for: NO3?, Cl?; 42 x + y[A]molecular weight < 44.82). The main reason was that the primary particles had different chemical compositions for the effects of the different kinds of anions and stoichio-chemical compositions of the primary particles. The effect degree of the anions depended on the co-existing anion radius in the reaction solution. According DTA-TG analysis of the cobalt compounds, the latter particles transform to Co3O4 powders on calcining. The shape of the Co3O4 particle with porous character has inheritance with precipitation. In this paper, it concludes that the particle formed by the principle of nucleation-aggregation in aqueous solution. The process of aggregation has played an important role in formation of particles. During calcination, the aggregation would be destroyed partly.

Jan 1, 2005

By G C. Bolton

Experiments were conducted to access the feasibility of removing zinc from lead slag by sulfation or chlorination or both. Gaseous sulfation with sulfur dioxide and oxygen released only 50 per cent of zinc even under the most severe conditions. Sulfation with concentrated sulfuric acid by a fast-leach process released 95 per cent of zinc while pug-roasting released a maximum of 78 per cent of zinc. Chloridization with NaCl in the presence of sulfating gas released 50 per cent of zinc, while direct chlorination with chlorine gas and oxygen released 85 per cent of zinc and 100 per cent of lead in a chloride condensate containing little impurities.

Jan 1, 1980

By F. A. Rutledge

The W. E. Dunkle mine, sometimes called the Costello Creek coal mine, is 8 miles N. 20° W. of Colorado Station on the Alaska Railroad. The presence of coal in this area has been known since the district was extensively prospected for gold between 1911 and 1915. At that time, coal from this deposit was used by miners for blacksmithing. The increased demand for coal resulting from government defense projects in Alaska led to exploitation of this deposit in 1941. The inability of Alaska coal mines to supply the quantity of coal required by public and private consumers and by the armed forces in Alaska was responsible for establishment by the Army of the Coal Procurement Section of its Alaska Department. It proposed to investigate the deposits and to expedite production from the Alaskan coal fields. The Bureau of Mines closely cooperated in this program. The quality of the Dunkle coal and the favorable location of the deposit caused it to be one of the properties chosen for investigation under a joint Army-Bureau of Mines-Geological Survey program.

Jan 1, 1948

By Steve Kral

MINExpo INTERNATIONL 2000 was a good place for companies to introduce new products, technologies and services to the mining industry. Caterpillar took that a step further. The company hosted a one-day preview of its mining products at its Tinaja Hills Training and Demonstration Center near Tucson, AZ. About 30 members of the trade press spent the day at Tinaja Hills before heading on to Las Vegas for MINExpo INTERNATIONAL 2000. Dozens of Caterpillar professionals provided the editors with a first-hand look at Caterpillar’s mining trucks, loaders, excavators, road graders, water trucks and engines. In addition, these Cat experts explained the intricacies of each piece of equipment, the latest technology that led their improvement and their value to the company’s mining customers.

Jan 1, 2000