Search Documents

"Introduction.The Bureau of Mines has taken up the problem of determining a method or methods whereby underground compensation insurance rates for metal-mining companies can be equalized in proportion to the underground hazards involved. This study has been started by the writer with the assistance of Mr. I. M. Wolfin* as consultant.The present paper briefly reviews the origin of accident compensation, gives a digest of State compensation laws, and describes types of insurance carriers. This will be followed by study of the basis of premium rate, risk differentials, and cost of compensation insurance to mine operators. These data will be supplemented by an analysis of the accident hazards in different mining methods and practices, and the severity and frequency of accidents classified by time lost and period of exposure to hazard, for different States, mining methods, occupations and nationalities. Attention will be given to standardized preventives for underground accidents in metal mines, and, finally, the classification of underground metal-mining hazard for workmen's compensation insurance premium rating."

Mar 1, 1924

By W. E. Roscoe, H. Agnerian

The contour method can be used to estimate the mineral resources of a mineralized body. It relies on geological interpretation and allows the geologist to determine the plunge of a mineralized ore shoot along the dipping plane of the mineralized body. The technique is best applied to estimate tonnage and average grade of relatively planar bodies, i.e., where the two dimensions of the mineralized body are much greater than the third dimension, such as Archean lode gold vein deposits or mantos of massive sulphide mineralization, based on exploration drilling. For these types of deposits, the contour method can provide a clear view of the “mineralization landscape” with “peaks” and “valleys” along the plane of the mineralized vein. The technique also reduces the “nugget effect” of local high values commonly present in gold deposits. With sufficient drill hole information, the contour method may be used to estimate the tonnage and average grade of individual blocks within a mineral deposit. General procedures for the contour method are described in this paper, along with examples and explanatory notes.

Jan 1, 2002

By R. J. Roman

During the refining of primary magnesium metal: a spent flux (sludge) is produced which is considered a dangerous waste by the Washington State Department of Ecology. Four years of research, testing and marketing has identified two beneficial markets for the spent flux: 1) as a fertilizer and soil admendment as a result of the material's high potash and nitrogen content and its high lime equivalence and 2), as a roadway deicing agent to clear roads of ice and snow as a result of both the salt content and the flux containing chemical compounds which exothermically react with water.

Jan 1, 1988

By H. Memarian

In the last few decades, many developing countries have tried to expand and improve upon higher education, which is acknowledged to be the leading factor for development. In this respect, develiping countries have significantly increased the number of tertiary institutions and their students. These rapid expansions, along with all the benefits, have drawbacks as well. An example is the status of mining engineering education in Iran. Presently, the number of active mining engineering departments in Iran (27) is more than the sum of similar departments in Canada, Australia, the United Kingdom, and South Africa (23 altogether). Also, the number of annual mining graduates in Iran (645) is more than the cumulative graduates of the United States, Canada, the United Kingdom, and Australia (613). The expansion of mining engineering education in Iran has coincided with the closing or merging of similar mining departments, as well as a decline in the number of interested students in the industrialized world. The present study shows that the need for development and the excessive number of high school graduates, resulting from high population growth in the early 1980s, are the two primary factors influencing the significant expansion of mining engineering education in Iran.

Jan 1, 2007

By Svato Prochazka

Content: ? commonly used drive systems ? drive system efficiency ? introduction to SR technology ? SR drive system advantages Commonly Used Feeder Drives Technologies ? VFD + induction motor ? hydraulic drive + hydraulic motor SR drive + SR motor

May 1, 2010

By Aquiles Figueroa L

Dado que en el altiplano existen yacimientos de estaño que requieren de nuevas tecnologías para una mejor recuperación metalúrgica, se ha diseñado pruebas experimentales de flotación del estaño con los relaves de San Rafael, adecuándola a las necesidades de la mina misma. Para ello, se describen los procesos de concentración de estaño (flotación de sulfuros, concentración de estaño) y las pruebas experimentales respectivas.

Oct 14, 1980

By Nicholas Macrae Steven

Abstract - The Shaba-type Luamata Cu-Co(-Ni) deposit (11°50_S, 24°28_E) is located in a tectonic slice of Katangan Roan Supergroup (Mines Group) sedimentary rocks, surrounded by younger Kundelungu Supergroup lithologies in the external fold and thrust belt of the Lufilian Arc. Luamata is a classic central African copper clearing in dense woodland, visible as a tonal botanical anomaly on Landsat imagery. Supergene Cu-Co mineralization (especially malachite and subordinate chalcocite, digenite, covellite, and copper and cobalt oxides) and, probably hypogene, bornite, and chalcopyrite are hosted by altered, but essentially unmetamorphosed, moderately dipping, dolostones and dolomitic shales. Alteration products include talcose dolomite, sericite rocks and intense silicification and brecciation. Friable yellow shale is best mineralized with cobalt (up to 0.43 wt%), whereas, highest copper grades occur in brecciated, silicified shale (up to 13.5 wt% CuO). Soil copper and cobalt contents are up to 2.2 and 0.6 wt%, respectively. A newly identified nickel zone (where soil contents exceed 0.1 wt% Ni) fringes the Cu-Co deposit. Polymictic, matrix-supported breccias with a calcareous matrix that underlie the Cu-Co deposit are interpreted to be fluidization breccias related to thrust tectonics and the emplacement of the Mines Group slice. Although small compared to the Kolwezi district Shaba deposits in the Democratic Republic of the Congo, Luamata exhibits all the classic features of an ore deposit type (with low calcite contents), whose high metal concentrations could potentially be very profitably exploited by low-cost opencast mining and hydrometallurgical recovery methods.

Jan 1, 2000

By Mutombo Nombe, Avimanyu Das, Rick Honaker

Enhanced gravity separators (EGS) provide a more efficient separation than froth flotation when cleaning coal in the 150 x 25 µm particle size range. To improve the performance of an EGS unit, air bubbles were injected into the feed stream in an attempt to decrease the apparent density of the coal particles due to the formation of bubble-coal particle agglomerates. Air injection had a significant impact on operating characteristics and separation performance. Coal recovery was increased by 10 to 20 absolute percentage points while a 2 percentage point drop in the minimum product ash content was also achieved.

Jan 1, 2005

By Paul M. Tyler

[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 rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the mining laws of specified French possessions in Africa has been prepared from the best information available 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. France controls large areas on the African continent, but the various Colonies and Dependencies are administered more or less independently. Algeria is under the direct jurisdiction of the Ministry of the Interior, and its mining laws are essentially the same as those of the mother country. Tunis and Morocco are attached to the Ministry of Foreign Affairs; separate digests of the mining laws' of these respective colonies have already been prepared by the United States Bureau of Mines. The present paper covers all other French territory on the continent of Africa except Somaliland, a rather small Colony including the port of Djibouti near the point where the Red Sea joins the Gulf of Aden. Available information indicates that the prospects of mineral production in this Colony, apart from salt and gypsum, are not at all encouraging.3]

Jan 1, 1933

By Charles A. Ashburner

VERY little is known of the economical value of the cod-bells of the State of Texas. The first authentic statement in regard to their occurrence is that contained in the reports of the United States Exploratians for the Pacific Railroad, near the 32d parallel of latitude, published in 1863-55. Professor William P. Biake reports, "that a number of seams of bituininorls coal, varying in thickness from two to four feet, have been opened along the Brazos River, in Young County, about one hundred and fifty miles west of Fort Worth." Dr: Shurunrd also states, " that the claracteristic fossil fornis of the Carbeiferaas Era have been found with this coal, and considers the age of the formation established. Foesils obtained from the carboniteroas limestone remove all doubt of the age of these deposits."† In the spring of 1879, I was called upon by some Eastern capitalisets to make an examination of the Brazos coal-field, in order to obtain the thickness, extent., and value of the coal which could be mined and be'made merchantable fir stearn, heating, and metallurgical purposes. The demand for coal in this section of the country is great, and a fuel which in our Eastern markets might be considered of inferior quality, would here find a ready sale. It must be remernbered that the market value of a coal does not depen'd upon its absoltite purity, but upon its actual value in heat units which it is capable of prodwing. A poor coal which can be cheaply milled near the consuper, is infinitely more remunerative to a mining company than a superior coal whose cost to the consumer is greatly increased by high mining charges and railroad freights. The value of the Texan coals does not depend upon their purity but upon their low first cost and nearness to a market. A glance at a geological map of the United States, will show that the Brazos coal-field is the extreme southwestern extension of what may be called the Missourian, Fourth or Western, bituminous coal

Jan 1, 1881

By Chetan P. Malhotra

This paper describes an online control system and simulation environment for reheating furnaces. The system can be configured for implementing manual control as well as automatic control using either look-up tables or online model predictions. The simulator is also used for offline generation of optimized normal operation and delay setpoints for look-up tables and generating ideal heating curves for model-based control. Finally, it is employed to compare the performance of the above control strategies over a typical period of operation of a pusher-type reheating furnace. Keywords: Reheating furnace, control strategy, model-based control

Jan 1, 2003

By Peter Moon

THE mineral industry of Canada relies heavily upon the talent of its technical men. It is vital to the well-being of the industry that its supply of young, trained men be adequate. At the present time, the industry is acquiring only 200 new graduates a year. The shrinking supply is far below present and future requirements. Other industries and research organizations are competing for engineers and scientists. Dr. J. B. Mawdsley (1), Past-President of the Canadian Institute of Mining and Metallurgy, has recently outlined a program designed to attack the problem. Dr. J'. C. Sproule (2), another former President of the Institute, has stated that: "The need for selection of trainee material is commonly recognized, but little is done about it." The following paper contains a short discussion of occupational interests, and outlines research, using psychological knowledge and measuring techniques, aimed at the identification of desirable recruits for the mineral industry.

Jan 1, 1963

By Alfred W. Eustes III

The first of a series on the evaluation of rock cutting tools, this paper discusses the results of full-scale laboratory drilling tests that compare the performances of several polycrystalline diamond cutter (PDC) coring bits. The tests were performed in welded tuff as part of a site characterization program. Number of cutters, size of cutters, air course design, and other parameters were evaluated as they affect penetration rate, but this paper focuses mainly on the relationships of torque vs. thrust (weight-on-bit), specific energy vs. penetration rate, and thrust vs. penetration rate. These relationships change in diagnostic ways according to bit type, bit condition, and type of welded tuff.

Jan 1, 1998

Two outstanding features of the world's young orogenic belts are their very consistently developed suites of volcanic rocks and, it is now recognized, the rather distinctive types of mineralization they contain. Further,it is now known that these volcanic suites exhibit evolutionary patterns, and it is beginning to appear that this evolution in style of igneous activity is accompanied by a parallel evolution in style of mineralization. Specifically,podiform chromite and stratiform pyritic copper ores of Alpine ultramafic/submarine tholeiite association progressively give way to more zincian stratiform ores associated with andesites and dacites, "porphyry copper"deposits developed in quartz dioritic to dacitic plugs, and lead-zinc stratiform ores related to increasingly pyroclastic, rbyodacitic volcanism.This "coupling" is exhibited well in the volcanic arcs - the young orogenic zones-of the SW Pacific which, with tbeir abundance of youthful and commonly unmetamorphosed materials provide an opportunity for investigating, through a petrochemical approach, the possible significance of ores in the elucidation of mechanisms of lava formation. It is suggested as a working hypothesis that in the orogenic (voleanic arc) regime ores are associated with the cale-alkaline rocks because these cale-alkaline rocks are in part generated by exhalative loss, and the ores are among the manifestations of tbat loss.

Jan 1, 1978

By P. Anciaux, T. Simpson

The competitiveness of the EU manufacturing industry has come to the forefront of EU politics. The systematic monitoring of developments and the review of the state of the competitiveness of economies and enterprises was identified as an essential component in this process. Work is currently being carried out within Enterprise and Industry Directorate-General in order to analyse the different factors that influence the competitiveness of the non-energy extractive industry. Such an assessment should help to identify policies and actions which could contribute to and enhance the competitiveness of the industry. Assessing the competitiveness and sustainability of the industry implies the need for reliable, consistent data. One important example of how this need is being addressed, is the development of sustainable development indicators (SDI) for the EU non-energy extractive industry. These seek to monitor the industry’s performance and provide a platform for openness and discussion. Work was started on the development of SDIs in 2000, and the first report was published in February 2004.

Jan 1, 2005

By Jeffrey W. Lin, Jonathan D. Abbott, Patrick R. Bowden, Tyson J. Plitt

Pentolite is a class of high explosives containing trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN) with PETN content typically ranging from 40 to 60 wt%. Manufacture involves melting TNT, 80 °C, followed by addition of PETN and trace ingredients to form a homogeneous mixture. Once a mix is ready to be poured, several factors can influence the behavior of the finished product including how long the mix has been at temperature and cooling rate. After the manufacturing process has been completed, storage conditions combined with manufacturing conditions may cause physical changes. Two such changes explored were exudation, liquid exuding from solid boosters, and ratchet growth, irreversible volumetric expansion. Exudation is principally caused by excess water in the process. Ratchet growth is a common phenomenon of nitroaromatic compounds such as TNT where time and temperature fluctuations can cause materials to increase volume, simultaneously decreasing density. Although neither phenomenon affects common attributes such as sensitivity, performance, and shelf-life, both can cause issues in storage and handling. In this study pentolite was cast into various forms under different manufacturing conditions and evaluated over several months of controlled storage conditions including ambient, temperature cycling and elevated isothermal. Subjective and objective measurements were made throughout the evaluation period with the aim to determine the preferred storage methodology.

Jan 21, 2025

By Hongjie Yu, Rakshith Shetty, Claudio Cimiotti, Nick Karlin, Mike Mooney, Vitaly Proshchenko, Matt Kendall

This paper documents an effort to explain cutterhead torque behavior observed during slurry pressure balance TBM tunneling through soft ground on the Los Angeles Clearwater project. AI machine learning and mechanics model-based learning was used to characterize cutterhead torque behavior including the TBM operating and ground parameters that influence cutterhead torque. Also, key parameters were from the slurry circuit data, including fines content, in-situ density, pore water fraction and solids content were included. The paper details what was learned using these new data-driven approaches as well as limitations with AI machine learning.

Jun 23, 2024

By H. Dreissen

Upgrading of low-concentration ores is of growing importance today. The Heavy Medium Cyclone Process, thanks to strong centrifugal forces, effectively separates particles varying only slightly in specific gravity but widely in size. The paper discusses the separation efficiency, the method of assessing that efficiency, and the influence of such factors as medium solids. The operating results of nine heavy medium cyclone plants handling following minerals are reported: barite, wolfram, iron, magnesite, diamond, lead-zinc, fluorspar, rocksalt potash. Highlighted are an improved recovery system for heavy medium and some other developments, such as techniques for separation down to 0.1mm and the application in the field of recycling.

Jan 1, 1980

By Raja V. Ramani, Robert L. Frantz

"The House/Senate Joint Conference Committee has instructed the Bureau of Mines to have the Advisory Committee on Mining and Mineral Resources Research review on an annual and simultaneous basis each generic mineral technology research center (GMTC). In order to accomplish that review promptly and uniformly, committee members have revised and approved an in-depth questionnaire. That document formed the basis of their review. The information provided by that questionnaire was an important factor in their recommendations concerning the future direction of the program; a presentation was made at the last National Plan Update.The comprehensive nature of the questionnaire and the scope of the information contained therein make it an excellent retrospective of the Center. Having a clear vision of where the Center has been and knowing where it is now will help guide it into the future. It is felt that such a detailed view of the Center's facilities and research program will be of value to Center personnel and Advisory Committee members.Each aspect of the questionnaire has been examined, answered in detail, and documented throughly. With the completed questionnaire as a guide, this volume examines the research program, Center personnel presently active on GMTC projects, number of graduate degrees granted with GMTC support, GMTC publications, degree of individual interaction, technology transfer, the reference center, GMTC equipment and facilities, and any envisioned plans for future research. It is hoped that this volume will serve as a review of the years 1984-1988, the first four years of the Center's operation."

Aug 31, 1989

By L. D. Jayaweera, R. G. Robins

The pocessing of gold bearing sulphide minerals wr ich contain arsenopyrite and other complex arsenic sulphide minerals results in arsenic containing emissions and effluents which must be given careful consideration in relation to clean air and clean water standards. The sources of arsenic and the various process options for treating arsenical gold ores and concentrates are briefly reviewed. The problem relating to the removal of arsenic from gaseous emissions from roasting processes is considered. Residues from aqueous processing contain a variety of arsenical materials which have not been characterised, and the long-term stability of these is suspect. 'rhe use of lime to stabilise aqueous residues as either calcium arsenate or calcium arsenite has been shown to be inadequate for long term disposal since both compounds are converted into calcium carbonate due to the influence of carbon dioxide in the atmosphere. Ferric ion solutions have been used to precipitate ferric arsenate or to form ferric hydroxide which binds the arsenic for short term disposal, The long term stability of these ferric materials is poor, but could lead to the acceptance of a slow release option rather than complete containment of residues.

Jan 1, 1991