Search Documents

By Peter Moser, G. Reihholf

Holcim, one of the world's leading suppliers of cement, aggregates and concrete, has set up a few years ago a working group “Quarry” in order to optimize the performance of its central European quarry operations in terms of work safety, environmental standards and economic performance. One of the activities of this working group "Quarry" addresses the subject of blast fragmentation in the quarries. A benchmark study of the blast work in all quarries has shown substantial differences for the various operations in terms of drill& blast costs. Especially big differences were found with respect to the drilling patterns as a function of the borehole diameters and with respect to the utilization of the borehole volume for charging the explosives.

Jan 1, 2006

The accompanying supply/demand flow diagrams and 10-year tables for mineral and fuel commodities present essential data required by government, industry, and others to formulate policies and programs that can help assure an adequate and continuing supply of mineral raw materials. The 10-year data base terminates with 1973 figures because adequate world information was not available beyond that date. Moreover, 1974 was an anomalous year with respect to prices, supply, and demand for many commodities. The selected mineral supply/demand tables and flow diagrams comprise but one "output" from the massive body of "information and data collected and com-piled by the Bureau of Mines on a continuing basis covering mineral production consumption, prices, shipments, imports, exports, and stocks, as well as industry activities in all States and abroad.

Jan 1, 1975

By S. H. Ash

For many years the Federal Bureau of Mines has been investigating fires and explosions in mines, tunnels, buildings, and hazardous processes of various kinds. Means and methods for controlling and extinguishing mine fires and preventing explosions and other accidents in many hazardous processes require the collection and analysis of samples of the atmospheres surrounding the sources of ignition. Complex mixtures of gases often encountered in mines, tunnels, and industrial processes may well presage imminent danger from explosions. This report discusses some practicable methods of utilizing the analyses of samples of complex mixtures of gases in their application to the many problems that arise from their presence.

Jan 1, 1948

INTERNATIONAL conferences on safety in mines originated in 1912 when, in response to an invitation issued by the United States, representatives of Austria-Hungary, Belgium, France, and Germany participated in a conference held in Pittsburgh, Pa The record shows that a permanent organization was proposed to be developed through. diplomatic channels. However, the advent of war 2 years later prevented this proposal from coming to fruition. No further cooperation between the Bureau of Mines and a group having: similar interests in a foreign country took place until 1924, when formal cooperation with the Safety in Mines Research Board of Great Britain was established. Interchange of personnel and results of research under that arrangement have resulted in a number of publications in both countries and more rapid advance in knowledge than could have been obtained through the same efforts exerted independently.

Jan 1, 1950

By H. E. Heide

"Before the war, the United States was the world’s leading consumer of tin, the industrial applications of which had become widespread. Domestic production was negligible, and requirements were met almost entirely by imports, principally from British Malaya, United Kingdom and China. Average annual imports for the years 1925-1929 amounted to 78,009 long tons.With the advent of war in Europe and signing of the Japanese-German pact, it was realized that foreign sources of supplies were threatened, and steps were taken by Congress to forestall critical shortages of tin and other minerals. These steps in regard to tin included stock-piling, improving reclamation and conservation, increasing South American production, constructing a smelter in the United States for treatment of tin, ores, and intensifying the search for domestic tin deposits. Annual imports were raised to 140,873 long tons by 1941. On 1945, annual imports had shrunk to 37,675 long tons and consumption had been reduced to 52,100 tons of primary and secondary tin but not tin content of scrap alloy.The Strategic Minerals Act, passed by the Congress in 1939, authorized the investigation of domestic tin deposits.As Alaska had supplied virtually all of the domestic output of tin, an investigation of Alaska deposits was undertaken in 1940 and 1941 by J. B. Mertie, Jr., and Robert R. Coats of the Geological Survey.The Lost River lode tin mine on the Seward Peninsula was examined by H. E. Heide of the Bureau of Mines in 1942. Possibilities for developing a significant amount of tin appeared favorable, and exploration of the ore bodies was started in August 1942."

Jul 1, 1946

By Brigitte J. Dejou

The Red Dog sediment-hosted zinc-lead deposit is located in the Brooks Range thrust belt in northwest Alaska, approximately 1000 km northwest of Anchorage. The mine constitutes the primary deposit in a 400 square kilometre district, which hosts several other mineral occurrences. All the known mineralisation is hosted by the Mississippian Ikalukrok Member, deep basinal shale of the Kuna Formation, part of a Devonian to Cretaceous sedimentary sequence. The rocks underwent intense deformation during the Brookian Orogeny in Middle Cretaceous time. Several thrust faults juxtapose the stratigraphy. The Red Dog mine is composed of four deposits which together contain 105 Mt in resources and reserves for a total resource exceeding 18 Mt of Zn metal. The mine is an open pit with 25 foot high benches. The biggest challenge is not the Arctic conditions, but metal extraction, due to the fine grained nature of the mineralisation and the variability of the ore. The mine produces Zn and Pb-Ag concentrates that are shipped to smelters around the world from the Red Dog port facilities during the short summer period. Ore mineralogy is generally simple and consists of sphalerite, pyrite, galena and marcasite. The deposits are generally overlain by decametre thick exhalative barite horizons and exhibit strong silicification, which locally obliterates the original textures. Although described as a world class Sedex-type deposit, a large portion of the mineralisation exhibits sub-surface replacement textures. Moreover, unlike most other Sedex deposits, the reconstruction of the basin is made difficult by the structural complexity of the district. To assist exploration in the district, several assumptions are made regarding the deposit settings relative to metal source, growth faults or crustal extension.

May 1, 2006

By Ji-He Wei

Keywords: stainless steel, AOD refining, side and top combined blowing, mixing characteristics, water modeling The fluid mixing characteristics in the bath during the side and top combined blowing AOD (argon-oxygen decarburization) refining process of stainless steel have preliminarily been investigated on a water model unit of a 120 t AOD converter. The geometric similarity ratio between the model and its prototype (including the side tuyeres and the top lances) was 1:4. On the basis of the theoretical calculations for the parameters of the gas streams in the side tuyeres and the top lances, the gas blowing rates used for the model have more reasonably been determined. The influence of the tuyere number and position arrangement, and the gas flow rates for side and top blowing on the characteristics has been examined. The results demonstrated that the liquid in the bath underwent vigorous circulatory motion during gas blowing, without obvious dead zone in the bath, resulting in a well mixing effectiveness. The gas flow rate of the main tuyere had a governing role on the characteristics, a suitable increase in the gas flow rate of the subtuyere could improve mixing efficiency, and the gas jet from top lance could make the mixing time prolong. Corresponding to the oxygen top blowing rate specified by the technology, a roughly equivalent and good mixing effectiveness could be reached by using six side tuyeres with an angle of 27 degrees between each tuyere, and five side tuyeres with an angular separation of 22.5 or 27 degrees between each tuyere. The relationships of the mixing time with the gas blowing rates of main-tuyeres and sub-tuyeres and top lance, the angle between each tuyere, and the tuyere number have been obtained.

Jan 1, 2005

By L. Tercero Espinoza, F. Marscheider-Weidemann, C. Gandenberger

"A reliable supply of non-energy raw materials is a precondition for the functioning of the European economy. In line with its importance, the issue of raw materials supply has become more prominent in the past years, especially owing to turbulent raw material markets. However, these turbulences are not due to depletion of the geological resources but to a missmatch of (expected) supply and (expected) demand, with several interacting factors influencing the markets both from the supply as well as from the demand side. A recent evaluation, published in June 2010 within the framework of the EU Raw Materials Initiative, sought to bring together these two sides of raw material markets and asked the question "which raw materials are critical for the EU?" Herein we present the methodology used by the Ad-hoc Working Group on Defining Critical Raw Materials and the results obtained, complemented by results from the study "Raw Materials for Emerging Technologies"."

Jan 1, 2011

The Nena high sulphidation-type copper-gold deposit is composed of andesitic pyroclastic units with minor interstratified lava flows. Epiclastic sandstone and conglomerate, and siliciclastic rocks consisting of mudstone, shale, lithic and bioclastic sandstone and conglomerate are locally present. Pre-mineral diorite intruded and domed the volcano-siliciclastic sequence. Economic copper-gold is hosted by vuggy quartz altered lapilli tuff and tuff breccia. The early hydrothermal alteration stage involved deposition of epithermal banded quartz and chalcedonic silica in localised environments. This alteration stage was locally superimposed by a hydrothermal breccia event. Following the breccia event, magmatically-derived volatiles were channelled through a NW striking dilational fault zone and generated the high sulphidation alteration. The high sulphidation alteration is zoned from a vuggy quartz core with local massive replacement silica through a broad pyritic quartz-alunite halo and finally to a thin illite-smectite zone. This is surrounded by regional chlorite-epidote-smectite alteration. A gangue mineral phase consisting of quartz, alunite and baryte overprinted the zoned high sulphidation alteration and preceded the main copper-gold-arsenic mineralisation. Early sulphide deposition is characterised by marcasite, arsenical pyrite and melnicovenite. Main-stage copper-gold mineralisation involved sequential deposition of hypogene bladed covellite+chalcocite, enargite-luzonite and luzonite+stibioluzonite respectively. The copper sulphides are zoned from bladed covellite-chalcocite in the north (cross-sections 5000 - 5600 N) through enargite-luzonite (cross-sections 4700 - 5000 N) and to luzonite????stibioluzonite in the south (cross-sections 4400 - 4700 N). A late phase of minor acicular covellite and enargite+luzonite overprinted the zoned copper sulphides and associated gold mineralisation. Gold mineralisation commenced at the transition from enargite to luzonite, and continued through the deposition of luzonite-stibioluzonite in both stages. Most gold was deposited during the main-stage mineralisation. Yellow native sulphur was deposited in the remaining vugs and defines the waning stage of the hydrothermal system. Post-mineral dioritic intrusives and feldspar porphyries intruded the volcano-siliciclastic sequence. Finally, supergene chemical processes with associated erosion and uplift generated a 40 - 50 m thick oxide-hosted gold cap. The oxide gold cap is underlain by a 35 - 45 m thick blanket of supergene chalcocite+covellite mineralisation which overlies and occurs throughout the main hypogene copper-gold zone. Supergene gold is related to the distribution of primary gold-bearing sulphides. Therefore, remobilisation and redeposition of gold are considered to be insignificant and very localised.

Jan 1, 1999

By J. P. Navarro

Se reporta el registro regional de las facies sedimentarias de la Formación Jumasha-Celendín, con la finalidad de entender su extensión, distribución y evolución vertical. Con ello se determinó la evolución sedimentológica y paleogeográfica de estas calizas durante el AlbianoConiciano. El sistema sedimentario comenzó en el Albiano superior con un cinturón regional carbonatado compuesto por ostras mezcladas con fuerte material terrígeno dadas en condiciones mesotróficas. Seguido por el levantamiento del bloque Marañon en la parte central de Perú, causando la instalación de un ambiente restringido de material terrígeno en condiciones oligotróficas durante el Cenomaniano superior.

May 1, 2008

By J. L. Moriarty, Irving Johnson, H. M. Feder

The crystallization of ternary alloys has been studied as a coprecipitation phenomenon by measuring the substitutional carrying of trace metals with CeCd11 precipitating from liquid cadmium. The Doerner-Hoskins logarithmic distribution law has been found to apply in all cases; the coprecipitation coefficients obtained were: 1.48 (La), 1.06 (Th), 0.63 (Pr), 0.24 (Gd), 0.17 (Sm), 0.13 (U), 0.10 (Er), 0.09 (Sr). Li, Na, K, Ba, Y, Sc, and Zr were not measurably carried. It has been observed that coprecipitation was most extensive for those tracers which form with cadmium an intermetallic compmdnd isostructural with CeCd11 or closely related thereto. For these tracers an inverse relation between Solubility in cadmium and coprecipitation coefficient was noted. THE partition of impurities between the liquid and solid phases of a metal or a congruently melting intermetallic compound has been extensively studied by the methods of zone melting.' However, when the composition of a liquid alloy and of the solid phase crystallizing from it differ grossly, partition of an impurity cannot be investigated in this manner. Partition of the impurity under equilibrium conditions may be studied by investigation of the appropriate phase diagram and partition under nonequi-librium conditions may be studied by observation of coring in the solidified alloys.2 The nonequilibrium case is of special interest in metallurgical practice because many complex alloys are cooled too rapidly to permit the uniform diffusion of impurities throughout the crystallizing phase(s). With this in mind, the present study was undertaken to obtain quantitative data on the phenomenon of coprecipitation via substitutional solid solution in certain metallic systems. It will be noticed that rather than adopting metallurgical ter- minology we have chosen to refer to the partition of impurities during alloy crystallization as coprecipitation.3 In the terminology of coprecipitation the impurity is referred to as the tracer and the precipitating phase as the carrier. From aqueous solution, coprecipitation may occur as a result of adsorption on the surface of the carrier, by occlusion of the liquid within the crystals, or by solid solution of the tracer in the carrier. By slow cooling of liquid metallic solutions it is relatively easy to form large, regular crystals of the carrier; the effects of adsorption and occlusion may be minimized and the influence of substitutional solid-solution formation may be made to predominate. Previous studies of the crystallization of some intermetallic compounds4 and of copper, silver, and gold5 have shown that the coprecipitation or partition behavior of trace metals is entirely analogous to that observed in aqueous systems when ionic substitution occurs, e.g., coprecipitation of Ra++ with BaSo4. The precipitation of CeCd11 from liquid cadmium was chosen for study. This choice was influenced by the following consideration. If the relative atomic sizes of the tracer atom and the atom for which it substitutes determine the tendency to coprecipi-tate, then a lattice having a substitutional site of well-defined size would be desirable. In CeCd116 (structure type cubic BaHg117) the cerium atom is completely surrounded by a cage of twelve nearly equidistant cadmium atoms. Thus, atoms much larger or much smaller than cerium should be poorly accommodated in this cage. The choice of a lanthanide central atom allowed the testing of the size hypothesis with a number of lanthanide tracers which differed in size but not in valence or electro-negativity. EXPERIMENTAL The general technique of this investigation was to prepare a slightly undersaturated solution of carrier in liquid cadmium to which a tracer was added. The concentration of tracer was always so low that saturation over the entire temperature range investigated was never exceeded. The solution was cooled in a stepwise fashion. After each step a por-

Jan 1, 1964

By J. E. Chappelear

We are concerned with the problem of calculating the forces produced by passing waves on a submerged object (in particular a drilling barge) located on the ocean floor. We employ the linearized theory of waves (the Airy1 theory), since solutions are generally more easily obtained in such a theory. It will be indicated how an approximate solution to the problem can be obtained for waves of finite height by use of a linear combination of Airy waves. We shall assume the submerged object has an infinite length, thus neglecting diffraction and making the problem two-dimensional. We find that there is not a considerable difference between our solution and the usual engineering solution. The force, as a function of time, is plotted in Figs. 4 and 5, together with the usual solution for easy comparison. So far, no experiments have been found to compare with the results. As will be shown, the calculations can be extended to waves of finite height (Stokes2-Struik3 waves) in an approximate fashion. This can be done by calculating the force produced by each Fourier component of the wave, separately, and omitting the coupling between the various harmonics produced by Bernoulli's theorem. The problem and its boundary conditions will be briefly stated. We seek a function, +, the velocity potential, which is harmonic, ?2?=0...........(1) and which satisfies the boundary conditions ??/?n =0 .......(2) (the normal derivative of + is zero) on the ocean floor and the sides of the barge, and s??/?y = ?..........(3) on the ocean surface, where s = g/w2........(4) The physical reasons for these choices and an interpretation of ? are given by Lamb.' As previously stated, we assume also that the problem is two-dimensional. We set up our coordinates such that x = 0 is the center of the barge and y = 0 is the ocean floor. The coordinates are shown in Fig. 1, together with the location of the barge on the bottom. Our solution may be decomposed into a function which is symmetric about x = 0,?e, and one which is antisymmetric, +,, ? = ? + ?o...........(5) Thus directly above the barge we have as boundary conditions that for x = 0, ?o = 0, ...........(6) and ??e/?x = 0........(7) Now, far from the barge, we have that (for x positive and assuming the waves are incident from the left) ?e ? Ae cosh ky cos k (x + a) , . . . (8) and ?e ? Ao cosh ky cos k (x + ß) . . . . (9) where + means ". .. approaches ... for x large." Let us put Ae, Ao, and k equal to one, and remember that, in accordance with the derivation of Eq. 3, a sinusoidal time factor is to be supplied. Then we may rewrite Eq. 8 for ?e, and we find that

Jan 1, 1958

By M. M. Cole

An assessment of the combined application of remotely sensed satellite imagery, geobotany and biogeochemistry reveals the complementary value of these techniques in the Thalanga area. The SPOT imagery yields useful information on features of the terrain and discriminates the gossan over the ore zone. Geobotany differentiates geological units and the anomalous vegetation provides visual expression of the surface presence of the ore zone, while biogeochemistry effectively locates its concealed extension below Tertiary sediments and ferricrete

Jan 1, 1991

By E. L. Garton

[Analyses of may crude oils produced in Louisiana are included in reports that t have boon published by the Bureau of Mines. The first report, giving, analyse of 6 Louisiana crude oils, was 3 published in 1921 and this was followed a year later by Report of Investigations 2416,4/ giving 7 additional analyses. The eleven most important of these analyses were incorporated in Bulletin 291.5/ issued in 1928 In 1934 analyses of 26 crude oils produced in southern Louisiana were published.6/ The percent report presents analyses of 72 additional samples of crude oil from 45 fields in 23 parishes In Louisiana.]

Jan 1, 1939

By E. A. Holbrook

The data in this bulletin were obtained during an investigation of screening practice by the University of Illinois engineering experiment station and the United States Bureau of Mines under a cooperative agreement between them and the State of Illinois Geological Survey Division. Earlier work on this subject includes a study of the general practice of coal preparation in Illinois, made in 1914 and published in 1916,1 and an investigation of Illinois coal-washing methods, results of which were published in 1912 in a bulletin 2 that contained complete information on the methods then in use for sizing washed coal. OBJECTS OF THE INVESTIGATION The present investigation was limited to a study of screening as applied in preparing mineral products with the expectation of obtaining more comprehensive information on screening machinery.

Jan 1, 1925

By Timothy C. Siegel

In response to a solicitation for ground improvement for the construction of a new hospital in Owensboro, Kentucky, the team of Berkel & Company Contractors and Dan Brown and Associates PC designed and installed lightly reinforced cast-in-place piles (known commercially as Cast-in place Ground improvement Elements or CGEs) as part of a composite ground system. The concept of the design is that the structure load is shared between the piles and the soil subgrade. The load sharing is controlled (to some degree) by the placement of a cushion between the pile head and the bottom of the overlying spread foundation. In an effort to confirm the design principles and to better understand the behavior of composite ground, the design-build team performed plate load tests on ground with a single CGE and with a group of CGEs. The small plate test (on ground with a single CGE) characterized the stiffness of the cushion. The large plate tests showed that the cushion will distribute the applied load to the CGEs and to the soil subgrade between the CGEs. On the basis of the plate tests, it was concluded that the plate stiffness can influence the test results. The use of a concrete layer was effective at supplementing the plate stiffness. The cushion was shown to be an important component of a composite ground system by allowing mobilization of the soil subgrade resistance and avoiding a stress concentration at the tops of the CGEs that would otherwise be present if the spread foundation and piles were rigidly connected. Because the composite ground system engages the resistance of the soil subgrade, the structural demand is reduced and consequently there is a potential for savings when compared to a conventional pile foundation. Several foundations for the new Owensboro hospital are being monitored for vertical movement during construction of the superstructure that will extend through 2011. At the time of this paper (mid 2011) the settlement of the foundations due to only part of the structural load (primarily the structural steel) has been negligible.

Jan 1, 2011

By James Westfield

This report covers the calendar year 1953 and has been prepared and submitted in accordance with the provisions of Sec. 106(a) and Sec. 212(c) of the Federal Coal Mine Safety Act (66 Stat. 692; 30 U.S.C. Secs. 451-483). During this first full calendar year of operations under the Federal Coal Mine Safety Act, the coal-mining industry of the United States attained the best injury records in its history - improving the former best records (made in 1952) by 91 fatal and 10,020 nonfatal injuries. Whereas, the mandatory provisions of the act were intended and designed to prevent major mine disasters, apparently the effects have reached beyond the scope thereof in reducing mine accidents generally.

Jan 1, 1954

By D Craw, P Lindsay, B Peake

The geochemical properties of Kaiata Mudstone and Brunner Coal Measures are evaluated in order to determine their suitability for placement at the proposed Cypress and existing Stockton mines. Correct scheduling of this waste material is needed in order to prevent sulfide oxidation and the generation of acid rock drainage. The Kaiata Mudstone has both acid generating and acid neutralizing properties. Results from this study and previous research from Kingett Mitchell Ltd (2003), indicate that within the Kaiata Mudstone sulphur content decreases with distance away from the Brunner Coal Measure/Kaiata Mudstone contact, while calcium carbonate content increases; sulphur values range from 0.33 to 4.23 wt %; and the acid neutralizing capacity ranges from 0 to 10.4 wt %. The Brunner Coal Measures have a low capacity to neutralize acid and sulphur content is variable ranging from 0.25 to 3.5 wt %. Appropriate control measures are therefore needed for the Brunner Coal Measures and any Kaiata Mudstone within close proximity to its contact. Tests have been undertaken to develop a rapid field or laboratory procedure to define the potentially acid-forming from the non-acid-forming Kaiata material. Results indicate that paste pH, Net Acid Generation (NAG) and Carbonate Bomb tests are suitable. Results from the Carbonate Bomb Test show a strong relationship with the Acid Neutralizing Capacity (ANC) and the Net Acid Production Potential (NAPP), indicating that this method may efficiently determine non-acid forming material in the field within fifteen minutes. Ongoing research includes kinetic column and shake extraction tests. These tests will quantify what trace elements could be leached from the waste rock and provide information on the usefulness of alkaline producing products such as Bauxsol, Limestone and Cement Kiln Dust.

Jan 1, 2004

By Bruce Hebblewhite

Australia’s Minerals Tertiary Education Council (MTEC) has achieved several successes during its first three years of operation. This initiative was developed through the Minerals Council of Australia, in conjunction with three partner universities involved in mining engineering education. The partner universities are the University of New South Wales (UNSW); Curtin University, the West Australian School of Mines (WASM); and the University of Queensland (UQ). The collaboration between these partner universities and industry has led to the development of shared course material, cross-institutional teaching arrangements, and the development of a number of flexible, distance-based delivery programs. This article then discusses future initiatives. Importantly, the challenge is the future initiative planned to cement this collaboration by the formation of a “virtual” national school of mining engineering: Mining Education Australia (MEA). This will provide a common third and fourth year program to all three universities beginning in 2007. The common program will involve innovative teaching and learning arrangements, greater student exchange potential and a more significant input by industry into the education process.

Jan 1, 2006

By Michael Radnor

The purpose of the study was to 1) examine the social and economic impacts of surface mine blasting in relation to variations in conditions of terrain and geology, population density and type, levels of ground motion and air blast; 2) consider technical, legal and government policy issues; and 3) examine the potential, nature and extent of surface mine blasting impacts and its regulations upon both communities and surface mining companies. Phase One designed the empirical research and technical analyses of Phase Two, focused upon surface coal mining and quarrying in the Eastern U.S. Several broad conclusions are evident: 1) blasting is not the major issue for communities or surface mine companies; 2) while the number of instances of severe cracking or annoyance are relatively small, the impact can be severe for individuals immediately involved; 3) blasting/drilling cost curves tend to rise significantly at intervals below 1.0 particle velocity, in/sec, dependent upon the size of a permit area and the size of a mine; and 4) the legal, complaint, cost and density analyses do not suggest the need for a general lowering of present regulations.

Jan 1, 1981