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By A. Kapito

The formation of bainite in steel is dependent on the size of the casting, the heat treatment, and the alloying elements. It is difficult to obtain a fully bainitic microstructure in steels during heat treatment because of its close proximity to the martensite (a?) reaction. The ferrite (a) and pearlite reactions in steels are also rapid and shield the bainite reaction. Alloying elements therefore need to be added to separate the bainite reaction. Boron (B) and molybdenum (Mo) are key elements added to bainitic steels because of their ability to retard the a reaction. Other elements used in the production of bainitic steels are silicon (Si), chromium (Cr), manganese (Mn), and titanium (Ti). In this paper we investigate the effect of alloying elements on the bainite reaction through the use of dilatometry. Dilatometry is a technique that determines phase transformations in the steel and through which continuous cooling transformation (CCT) curves can then be developed. Some initial results are presented of an ongoing study on the development of bainitic steels for railway wheel applications.

Jan 1, 2013

By A. Taylor, M. Blanchette, J. Doucet

"A Z1600 Jameson Cell Test Rig was rented for test work at Vale’s Clarabelle Mill operation. This paper discusses the evolution of renting the unit for test purposes to owning the unit and operating it as a revenue generating process component. The paper focuses on three aspects of the Z1600 project; the initial rental and installation, the test work performed in the cleaning circuit, and the business factors which led to the unit being permanently incorporated into the copper circuit.INTRODUCTION Clarabelle Mill is located in Sudbury Ontario (approximately 350 km north of Toronto) on the southwest rim of the Sudbury basin a meteoric impact crater that is 62 km long and 30 km wide. The result of the meteoric impact was concentrated nickel (Ni), copper (Cu) and platinum group metal (PGM) ore bodies in the outer perimeter of the basin; described in more detail by Hanley (1957). Vale currently has seven operating mines in the Sudbury basin, from which nine distinct ore types are mined. Ores are also received from two QuadraFNX mines. Clarabelle Mill processes all of these ores for the Ontario Operations of Vale. The mill, commissioned in 1971, was originally built as one of four mills operated by then Inco Limited. Between the late 70’s and the early 90’s process changes were made to consolidate the Sudbury Operations milling processes into a single operating mill, Clarabelle Mill. In 1990, the SAG mill was installed resulting in peak mill throughput of 11.9 million short tons per annum (Mstpa), with typical throughputs of ~10 Mstpa. Mill average feed grades were 1.4% Cu and 1.2% Ni. During the resources boom, plans were developed to increase the mill capacity at Clarabelle Mill in stages to a final capacity of 13.5 Mstpa. The project known as the Clarabelle Mill Expansion and Recovery Project (CMERP) included expansion and reconfiguration of the grinding and flotation circuits. The first stage was a planned increase in grinding capacity with the reallocation of existing mills, the existing flotation capacity would be required to treat higher throughput until the new flotation circuit was constructed."

Jan 1, 2012

By W. I. Nissen

This Bureau of Mines report presents the design for a commercial-sized flue gas desulfurization (FGD) demonstration plant that uses the citrate process. The goal of the Bureau's citrate process is to minimize the undesirable environmental impacts of industrial plants emitting SO2-bearing gas. The FGD plant is located at the George F. Weaton powerplant, Monaca, Pa. Construction was completed in April 1979 and will be followed by preliminary testing and a 1-year testing and evaluation program. Design capacity of the FGD plant is 156,000 scfm of 0.2-volume-percent-SO2 flue gas yielding about 16 tons of sulfur per day. The plant is intended to (1) clean fly ash, SO2, and Cl- from the gas while cooling the gas in a venturi scrubber, (2) absorb SO2 from the gas using 1,200 gpm of a countercurrent-flowing citric acid-sodium citrate-sodium thiosulfate solution, (3) react the absorbed SO2 in two 13,000-gal stirred closed vessels with added H2S, thus precipitating elemental sulfur and regenerating the citrate solution for recycle, and (4) recover the sulfur from the slurry by air flotation, followed by melting in a heat exchanger and separation from the occluded citrate solution in a sulfur decanter at 35 psi and 135° C.

Jan 1, 1979

By S. R. B. Cooke, H. S. Choi, I. Iwasaki

In a previous article1 the function of various fatty acids as collectors for iron ores was reported for the two alternate processes; (a) the flotation of iron-oxide minerals, and (b) the flotation of calcium-activated siliceous gangue. The selectivity of separation was shown to be markedly dependent not only on such common parameters as pH and the levels of collector and activator addition, but also on the structure and the degree of unsaturation of the acids used. The iron ores employed consisted primarily of hematite, goethite, and quartz and as the effectiveness of any one acid on the separation depends on the individual response of each constituent mineral toward the given collector, a comprehensive knowledge of the floatability of the individual minerals is desirable for the interpretation of the results obtained. The mechanism by which a collector ion becomes attached to a mineral-solution interface has been a subject of much investigation. From quantitative studies of the properties of the electrical double layer on mercury2 and on several solid surfaces3,4,5,6 , the adsorption of some flotation reagents at the mineral-solution interface is beginning to be understood. For example, it has been demonstrated from streaming potential measurements made on quartz5 and corundum6 that the interfacial electrical condition is strongly dependent on the pH. Thisoccurs presumably through the following electrolytic reaction at the interface, and in the presence of a flotation collector, controls the floatability of the solids. A concurrent investigation of the flotation behavior of goethite and of quartz carried out at the School of Mines and Metallurgy7 has shown a positive correlation with the electrokinetic behavior of these minerals. The purpose of the present investigation was to collect general information on the floatability of hematite, and to investigate the function of various 18-carbon aliphatic acids on the floatability of hematite, goethite, and of activated quartz. Electrophoretic mobility measurements, simplified flotation tests using a modified Hallimond tube, and contact angle and frothability measurements were employed. The results are of direct application in the interpretation of the batch flotation results on natural ores as

Jan 1, 1961

By Harold E. Marr

A simple algorithm is presented for processing digitized X-ray spectra obtained with a Si(Li) or Ge(Li) semiconductor detector coupled to a multi- channel analyzer. The simplified least-squares procedure is used to smooth out the statistical fluctuations in the spectrum by repeatedly fitting a quad- ratic equation to a predetermined number of channels and performing a traveling smooth across the spectrum. A logarithmic transform is applied to the raw data to minimize the distortion of the gaussian-shaped peak profiles. The efficacy of the technique is evaluated by observing the distortion of several gaussian-shaped peaks that have been subjected to the smoothing operation. The locations of maximums and minimums in the spectrum are predicted in the process as well as the values of the peak heights. The convolution integers from a least-squares fit of a quadratic equation are calculated as part of a FORTRAN subroutine. The building-block approach to computer programing in a small laboratory is discussed.

Jan 1, 1972

By L. K. Weaver

The objective of this study is twofold, The first is to present the composition of the offshore petroleum industry in terms of lease bonuses and the value of hydrocarbons produced from Federal offshore tracts. The second is to present costs of producing petroleum (oil and condensate) in the Gulf of Mexico with a financial analysis of an offshore operation. To prepare a financial analysis of an offshore operation, a model was derived to show the costs necessary to explore, acquire, develop, produce, and abandon a 5,000-acre block and the estimated income from the sale of the hydrocarbons produced. To establish cost and income guidelines for the model, a group of seven oilfields in the Gulf of Mexico ranging from 7 to 75 miles from shore and in water 20 to 130 feet deep was selected for study. A net profit or loss statement was prepared for each field and a discounted cash flow rate of return was calculated. Discounted cash flow rates of return for the seven fields range from 1.1 to 19.5 percent. Under the two specified conditions set up for the model (a 20-year and a 30-year oil depletion model), the rates of return are 17.2 and 13.7 percent, respectively. To January 1, 1959, the top four operators in the Federal offshore areas had paid approximately 40 percent of the amount spent on all lease bonuses and produced about 56 percent of the total hydrocarbons.

Jan 1, 1972

By Gustav Wade

"INTRODUCTION Analyses of samples of crude oil from several Texas oil fields have been published from time to time in Bureau of Mines reports, some of which are out of print, but many other analyses of Texas crude oils have not been published. The purpose of this paper is to make available in condensed tabular form under one cover all analyses of the Texas crude oils that have been examined by the Bureau of Mines.DIVISION OF TABLEThe table of analyses is divided into six parts in accordance with the geographic subdivisions of the State. (See fig. 1.) This grouping of the oils corresponds only in a general way with the principal formations in each area from which oil is being produced. In general, the principal oil-producing formations in the Texas Panhandle and West Texas areas are of Permian age; those of North Texas are of Pennsylvanian and older ages; those of the East Texas Basin and of Central Texas are of Cretaceous age; and those of the Texas Gulf Coast are of Eocene and younger ages.For convenience in presentation the name of the geologic age has been assigned to each group of the table although same of the oils included in the group may be of another age.Group 1 includes oils of Permian age produced in the Texas Panhandle area, which comprises the following counties: Dallam, Sherman, Hansford, Ochiltree, Lipscomb, Hartley, Moore, Hutchinson, Roberts, Hemphill, Oldham, Potter, Carson, Gray, Wheeler, Deaf Smith, Randall, Armstrong, Donley, Collingsworth, Parmer, Castro, Swisher, Briscoe, Ball, and Childress."

Dec 1, 1934

By Pavel Vasak

The Laurentian University Virtual Reality Laboratory (VRL) has provided a unique platform for the development and testing of novel seismic and microseismic data processing and visualization technology. In collaboration with Vale?s Creighton Mine, the technology was implemented at the mine site and consists of a VRL system and site calibrated Seismic Excavation Hazard Map (SEHM) software. The SEHM was developed as a practical solution for the mine operator to identify areas of elevated, active rock mass damage processes caused by recent mining activity. This paper is a pictorial representation of the 3D stereoscopic demonstration of the Creighton Mine seismic data distribution and interpreted SEHM for the first quarter of 2009. A live demonstration is scheduled at the Laurentian University VRL as one of the conference field trips. The demonstration highlights the technology transfer of research concepts into a near-real-time excavation hazard system that utilizes the key aspects of virtual reality technology; the ability to integrate large datasets (geology, mine excavation, (seismic) monitoring data, production scheduling, stress model, etc.); the ability to manipulate and visualize large datasets in both space and in time (mining sequence); and the ability to review the datasets by a group of experts in an immersive (3D stereoscopic), collaborative environment to better understand the processes and context of the mining-induced seismicity and evaluate potential risks to the mining operation.

Oct 1, 2010

By A. R. T. Denues

[Liquid oxygen explosives are ordinarily made from a carbonaceous absorbent and from liquid oxygen of high purity. These explosives have a limited but definite field of usefulness; their properties have been described in the literature, which includes several publications of the Bureau of Mines, the most recent dealing with fire-retardant treatments.3/ It seems generally conceded that the outstanding hazards in the use of these explosives are their high inflammability and their relative sensitivity to mechanical action. Each of these topics has been studied, and some interesting practical results have been obtained. Treatments have been described that render liquid-oxygen explosives prepared from granular carbonaceous absorbents practically immune to the action of igniting agents representing or exceeding practical hazards in violence.]

Jan 1, 1941

By A Buckley

Many policy issues facing the mining industry and affected communities are at a level of complexity that they can be called ‘wicked’ problems. The term ‘wicked’ in this context is used, not in the sense of iniquity, but rather as social and economic issues highly resistant to resolution. For the resource extraction sector and affected communities there are an array of challenges embedded in the industry’s production and profit paradigm, the remoteness of mineral reserves and affected communities’ expectations of economic benefit and a positive legacy. The mining industry as a whole is dominated by economic, political, legislative and market structures that influence and constrain interactions between mine operations and local communities. For communities, with particular reference to regional Western Australia, intractable problems include the uncertainty of, yet increasing dependence on, a mining economy. Questionable outcomes for local communities include the limited realisation of local employment and business development benefits, and low overall outcomes or low multiplier effects. ‘Wicked’ problems, according to the literature, are best addressed via collaboration. In the mid-west region of WA, with mining and infrastructure construction underway, alliances have formed between mining companies, the major port and rail infrastructure project (Oakajee Port and Rail) and regional and local governance stakeholders. The major impetus for these affiliations is to expedite planning and associated infrastructure development taking into account the lessons from other mineral-led regions. What has resulted is an array of innovative approaches to stubborn problems including planning well in advance of full-scale mining; regionally coordinated procurement; ‘mine ready’ local businesses; and strategic investments in social infrastructure; including community trust funds paid in advance of project delivery. This paper examines these innovative approaches/alliances and assesses their effectiveness in addressing long standing mining/community dilemmas.

Nov 22, 2011

By Harry A. Schrecengost

The Bureau of Mines has found considerable lack of uniformity in style and content of record books used for reporting the results of examinations made by coal-mine officials. These books range from elaborate forms designed for specific examining and operating procedures at certain large mines to simple composition books, tablets, and pocket-style notebooks at other mines. Examination of thousands of these record books discloses that the reports of many examinations are so brief and so poorly worded that they cannot be understood readily. The contents, in some instances, appear to be deliberately ambiguous. The value of keeping accurate accounts of safety inspections in coal mines is often underestimated. Well-kept records reflect managerial attitude and indicate well-governed operations as well as training of official personnel to conform to considered policy and regulations and if necessary, may serve as documentary evidence to protect the mine officials and the operators.

Jan 1, 1962

By Christopher J. Bise

INTRODUCTION Traditionally, the purpose of mine ventilation has been defined as diluting, rendering harmless, and sweeping away hazardous gases which may accumulate in the mine workings. In addition, the ventilation sys- tem must keep the mine air as close as possible to the composition of the outside air in order to provide a healthy environment for mineworkers and to prolong the useful life of mine equipment. When plans are being developed for opening a new mine, sound engineering dictates that a calculated estimate be made of both the maximum air quantity requirement and the accept- able mine pressure (head) loss related to the under- ground layout and projections. For efficient mine ventilation, the two problem areas that demand constant attention are (1) the control of fugitive air (through short circuiting or leakage) and (2) the provision of ample airway capacity. Fugitive air is that quantity of air which enters the mine but short-circuits the mine ventilation system through improperly constructed stoppings, doors, overcasts, etc.; it represents an investment in power consumption (to move the air by the fan) while providing little, if any, return on the investment. Typically, efficient mines are those that can deliver 50% of the air handled by their fans to the working faces. Paying close attention to a new mine's ventilation system at the outset can provide numerous benefits during the later stages of mine development. It has often been noted that the main cause of trouble in many mine ventilation systems can be found within a radius of 2500 ft from the fan installation. Ample airway capacity is essential to maintain the mine's head loss within manageable limits. Similar to an industrial ventilation setting, the mine's headings are the ductwork for the handling of air. The difference between normal industrial ventilation and mine ventilation is apparent when more capacity is needed; a plant can install new or larger ductwork, but it is difficult for a mine to install new entries or enlarge existing entries. Air velocities are usually maintained under 800 fpm to limit the stirring up of dust in the intakes. With this in mind, it is usually simple to estimate the number of entries required in the ventilation system. The problem that often arises, though, is when the system's capacity is overestimated and the required head loss to achieve the desired quantity is excessive. Experience has shown that problems are often encountered when the mine's condition requires much more than three inches of water gage to ventilate the mine on a day-to-day basis. Thus, if proper attention is not paid to these parameters in the preplanning and initial development of a new mine, it may take an extremely high water gage to achieve the ultimate quantity. This chapter will not delve deeply into the theory of mine ventilation; many other books have been writ- ten on that subject. Instead, the following sections will point out the important considerations that should take place before the development of a mine ventilation system, as they relate to normal industry practice. FUNDAMENTALS OF AIRFLOW Volume Versus Water Gage The common method of measuring ventilation pressure is in terms of inches of water gage (wg); one inch of water corresponds to a pressure of 5.2 psf (pounds per square foot). Further, airflow follows a square-law relationship between volumes and pressures where, as shown in the previous section, a doubling of quantity requires a quadrupling of pressure. Table 1 shows how heads and quantities are related. Using Table 1, it is readily apparent that, for the same mining conditions, an increase in pressure from one inch wg to three inches wg results in only 34,640 cfm when the initial quantity is 20,000 cfm. Pressure Losses Pressure losses in mine ventilation systems are caused by friction between the heading walls and the air stream and by shock losses due to abrupt changes of the air stream caused by obstructions. The common pressure-loss formula for mine ventilation is: [ ] where H is the pressure loss in inches of water gage, K is the coefficient of friction, L is the length of the airway in feet, 0 is the airway perimeter in feet, V is the air velocity in feet per minute, and A is the cross-sectional area of the airway in square feet. Table 2 lists the US Bureau of Mines schedule of friction factors (K) for mine airways. Recent research indicates that the values of K are slightly less for coal mines than those presented in the USBM Schedule, and Table 3 should be consulted in this instance. It should be

Jan 1, 1986

By J. J. Carlson

Studies were carried out to determine whether filtration rate changes observed in an iron ore concentrator were due to variations in particle shape. It was confirmed that ores mined from different locations differed in filtration rates by as much as 60%. However, when image analysis was used to quantify the shapes of the individual particles in the filtration feed, it was found that the particle shapes showed almost no variation, and the shapes did not correlate with the filtration rate. It was also determined that the filtration rate variations were not caused by changes in particle size distribution. These results suggest that the differences in filtration rate are due to factors other than size and shape, such as surface chemistry.

Jan 1, 2008

By Richard F. Hewlett

Engineers at the Bureau of Mines Denver Mining Research Center have been a research program investigating the theory and application of mine sampling. Part of this program is an investigation of the efficiency of sampling methods that involves development of sampling-method theory through simulating ore-deposit samples and assays, using - electronic digital computer. Theoretical developments are checked against actual ore-deposit sampling, assay, and production data by the commonly used polygonal and triangular methods of computing grade and tonnage of ore reserves. To speed the computing procedures, a program has been developed utilizing a medium-size digital computer for computing ore reserves by the polygonal method. This program calculates nine prismoids per minute at a total cost of $0.21 per prismoid. The complete program, written for an augmented IBM 650 computer, is described in detail; it can be used without change for computing ore reserves for a low-grade deposit. Modifications necessary to convert the program to compute ore reserves for virtually any other type of deposit or grouping of ore horizons also are given; however, the program is limited to using only vertical drill-hole data.

Jan 1, 1962

By Francisco Anglade

Dado que la simulación digital es una herramienta auxilar para los ingenieros de procesos -en tanto evalúa la factibilidad de un flowsheet propuesto y predice el efecto de una modificación para un flowsheet existente, su importancia también se extiende también a la evaluación de alternativas para las estrategias de control en los circuitos de la planta. En ese sentido, el presente trabajo señala los beneficios económicos y técnicos obtenidos en la planta San Rafael mediante el empleo de simuladores en los circuitos de molienda, chancado y concentración gravimétrica, los cuales permiten corroborar los cambios efectuados u optimizar los circuitos señalados de forma simple y rápida.

Sep 9, 2007

By Zsuzsanna Zborovszky

[Certain chapters of the tentative document entitled, "Test Requirements for instruments & Apparatus to be Considered for MESA Intrinsically Safe Certification" are evaluated and supporting data are presented on certain key issues with the purpose of helping the regulatory agency in improving the above document. The subjects discussed in detail are: hot wire ignition with W and BeCu wires; the most sensitive methane-air :and propane air ratio; the ignition limits for inductive-resistive circuits in 8.3°; methane-air mixtures in the 24-OV, 100 mH-2 [ ]H range, the resistive ignition limit as a special case when L ? 0; the capacitive-resistive ignition limit representing a four ,dimensional problem is analyzed and discussed in general and the variation of the ignition limit using Vo and/or r2 as a parameter are determined experimentally. The ignition limit is also determined for the [r1 ,~ r2] = 0 case ("capacitor alone") and for the most dangerous capacitive resistive circuit combination. The ignition limits are below the limits proposed in the document. A survey of the different factors influencing the ignition is made as to their suitability to provide a constant safety factor. It is shown that a constant safety factor cannot be achieved. The best method for applying a safety factor appears to be the increase of initial pressure or use of other gas mixture. The revision of the safety factor concept and ignition limit curves is recommended.]

Jan 1, 1980

By J. P. Rider

Operating practices and resulting production from longwall faces are continually improving. Consequently, longwall operators are continually seeking to improve the dust control capabilities on longwalls. The National Institute for Occupational Safety and Health (NIOSH) has been conducting dust surveys at longwalls throughout the country in an effort to document the types of controls that are being used and to quantify the relative effectiveness of these controls. To date, surveys have been completed at longwalls in Alabama, Colorado, Pennsylvania, Utah, and West Virginia. In addition NIOSH has been reviewing longwall dust parameters provided by mine operators to MSHA to assess the status of dust control technology being used throughout the industry. Results from the underground dust surveys and information obtained from MSHA will be summarized in this paper to provide an update on longwall dust control technology and practices.

By Martin D. Conyac

A 1984 Bureau of Mines investigation identified ho mineral resources in the Wilderness Study Area (WSA). However, four prospects in the WSA contain anomalous amounts of copper and silver minerals; one had traces of gold. Stratabound copper-silver occurrences appear to be prevalent. Quartz veins in the WSA locally contain trace gold, and one mine adjacent to the area produced some gold in the late 1800's. The WSA is underlain principally by Precambrian and early to middle Paleozoic quartzites, argillites, dolomites and limestones that have been complicated by faulting, generally tilted northeastward, and thrust southeastward over sequences of late Paleozoic sedimentary rocks. The stratabound copper-silver occurrences and gold-quartz veins are in Precambrian and Cambrian rocks in the western part of the WSA, as are similar deposits regionally. Sand and gravel, and limestone are abundant, but plentiful resources of these commodities are nearer established markets. In November 1983 there were 5 small groups of current claims oh the WSA boundary; none are patented claims. Probably less than 35 claims have been located within the WSA, mostly in the northwestern portion; hut over 100 claims have been located outside, near the northwestern boundary. Oil and gas leases nearly surround the boundary and 6 extend up to 1 mile into the study area. There has been no recorded mineral production from within the WSA. From 3 to 5 miles to the west, several lode nines in the Johnnie district have produced several million dollars worth of gold from quartz veins, and some silver and lead from galena-calcite veins. These veins generally trend northeasterly and dip northwesterly and probably do hot extend into the study area.

Jan 1, 1985

By Roberto Chambi

"El presente trabajo señala la expansión de la producción de la mina Condestable a través de las innovaciones tecnológicas en clasificación de molienda como: la utilización de estas zarandas derrick de cinco pisos cada uno, donde se aumenta la capacidad de cada molino instalado en planta en un 17% en promedio, así como el grado concentrado supera el promedio de 26.35%."

Sep 9, 2007

By Yue-yuan Li

China has abundant magnesite resource, but the low-grade and powder ores have always been rejected, which influences the comprehensive utilization of resource and often causes circumstance problems. The present work investigated the preparation of magnesia whisker using magnesite tailings as starting materials by preparation magnesium carbonate whisker as precursor firstly in the route of calcination, hydration, carbonation and pyrolysis, follows by second calcination of the precursor. The influence of pyrolysis conditions and additives on morphology of magnesium carbonate crystal as well as the influence of calcination conditions on morphology of magnesia whisker was investigated. The results showed that thermal decomposition products was MgCO3?3H2O. Magnesium carbonate whisker with length of 10~60 µm and the length-to-diameter ratio of 10~20 was prepared when soluble magnesium salt was added. While temperature was elevated at 1°C?min-1, magnesia whisker with length of 10~60µm was obtained.

Jan 1, 2010