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By N. R. Thote, J. L. Porathur, C. P. Verma

Highwall mining is a highly mechanized coal mining method associated with several advantages, such as a very high production rate (approximately 3,000 t/d) and low production costs. There is no requirement for underground support, ventilation, or blasting. Production leads to added recovery, which is otherwise lost in the ultimate pit. The use of highwall mining can bridge the gap that exists between supply and demand in the energy sector. This paper presents a brief review of highwall mining technology, including current status, analysis tools, and design techniques. In addition, it identifies important parameters from the analysis of failure case studies.

Jan 1, 2014

By Antonio Esposito

Saving energy and reducing pollution by minimizing emissions are today great challenges in the coking industry worldwide. In order to achieve satisfying results, equipment as well as technology should be continuously improved and updated. The most modern design tools should be adopted to maximize the coke production rate also ensuring the best coke quality. In this scenario, Paul Wurth is realizing the new coke making plant of CSPecem, Ceara - Brazil. These batteries are based on Paul Wurth “jumbo oven concept”. This solution incorporates all most modern features and design upgrading, in the aim of an easy and long-lasting operation putting a particular attention to environmental performances: the reduced number of ovens and the low number of pushing per day have the main effect of reducing pollution sources. Finally the paper will highlight Paul Wurth SOPRECO® System, which is foreseen to be installed in CSPecem batteries. SOPRECO®, which is capable of controlling the pressure for each individual oven in a coke oven battery, is thus able to reduce volatile emissions through doors, roofs and stand pipes up to 90%. The coke oven gas (COG) produced during the carbonization process is cleaned in a coke oven gas treatment plant to the level stipulated by applying the Best Available Technology (BAT).

Aug 1, 2018

By Jens Kempken

A competitive landscape pressurizes the steel producers business, zero defect requirements from customers forces the operators for additional efforts in process control and quality management. The so called quality related cost, which include also rework, cost for downgrading or even scabbing of material is already a remarkable lever in a plants profitability breakdown. The introduction of advanced state of the art grades in the product portfolio requires already a budgeting for the expenses for R&D and quality management. PQA has been developed as a process and quality management software solution next to existing level 2 or level 3 automation systems. It is focusing on the analysis of process data, equipment information, in line quality measurement devices and trend analysis to obtain an answer whether the process is according to definition and expectation and whether the intermediate or final product can be shipped for further processing as prime material. Advanced analytics which are linked to an expert know how based configuration identifies deficiencies in the production and processing process. An intelligent, state of the art quality rating system evaluates tolerable deviations. PQA comprises the software platform including the database, data configurator and collector from the different sources in the production process and units. The core element of the platform is the knowledge based expert know how package defining process and quality determining fundamentals. The paper describes the structure of the software package, it gives insights on the expert know how package, process and quality evaluation and points out the customer benefits, cost reduction, improvement yield, customer satisfaction increase. The link to recent operational references is given.

Oct 30, 2017

By R. H. Jefferson

An electrochemical method to selectively determine sulfur dioxide in the presence of sulfur trioxide was investigated. A hydrophobic gas-permeable membrane separates the gas sample solution from an internal filling solution containing a fixed quantity of chloride ion and a sufficiently large excess of sodium bisulfite so that its concentration may be considered constant. Sulfur dioxide diffuses through the membrane to dissolve in the internal filling solution and liberates an equivalent quantity of hydrogen ions. The electromotive force between a precision-ground, flat-ended pH electrode, which acts as the sensing element, and a chloride sensing electrode, which acts as the reference element, gives a direct measure of S02 in the gas sample solution. Calibration curves in water, tetrachloromercurate (TCM) , and citrate buffer absorption solutions were closely parallel with slopes in their linear segments, ranging from 57 to 52 mv/decade of S02 concentration. The slopes compare reasonably well with the theoretically expected slope of 58 millivolts at 21° C. The water standard curve was linear with respect to the logarithm of S02 concentration from 1 to 1,000 ppm S02; the TCM standard curve was linear from 10 to 2,000 ppm S02; and the citrate standard curve was linear from 30 to 5,000 ppm S02' The high efficiency and nontoxicity of citrate favor it as a substitute for the conventionally used TCM in the absorption solution.

Jan 1, 1976

By W. R. Reed, G. W. Luxbacher

As directed by the MINER act of 2006, the NIOSH Office of Mine Health & Safety Research (OMSHR) has annually awarded contracts to enhance mine safety and health. OMSHR has a history of research that focuses on both respirable coal mine dust and respirable crystalline silica (or quartz) dust, and contracts have been awarded since 2010 in support of our intramural research efforts. In 2018, a National Academies of Science consensus study report recommended expansion of respirable dust research. As a result, beginning in 2018 through 2021, eighteen contracts were awarded focusing on this area. These contracts can be grouped in three topic areas: characterization of coal/dust, development of real time monitors, and improvement of respirable dust controls. This paper summarizes the outcomes of completed contracts and the progress of current contracts.

Mar 2, 2022

By S. A. Pirzada

A thermal plasma assisted laminar flow reactor has been used to evaluate the kinetics of converting alumina to sodium aluminate in flight. Free energy minimization calculations were used to determine experimental conditions. The experimental variables include: alumina particle size, alumina/sodium nitrate molar ratio, temperature and residence time. A mathematical model for the conversion was developed and validated. Experimental and mathematical results are presented.

Jan 1, 1996

By J. A. Sanchidrián, P. Segarra, S. Gómez

Blasting is a common activity in mining that can cause significant damage in the remaining rock mass. The most commonly used method for predicting vibrations is the Swedish or Holmberg-Persson approach. It is a simple and fast method that uses empirical formulation to estimate the vibration levels based on the explosive charge weight, distance to the source, and other parameters. However, it has limited accuracy and does not consider the effect of free surfaces or other boundary conditions. On the other hand, recently developed methods as the full-field solution (FFS) can provide more accurate predictions of vibrations due to excitations provoked by cylindrical columns of explosive, but the inclusion of free surfaces in analytical methods is a challenging problem. This paper presents a new approach that includes free surfaces in the FFS to predict vibrations analytically in the near-field. The main obstacle to including free surfaces in the FFS was the belief that the solution was non-decoupleable in P- and SV-waves separately. The Heelan's approach was previously used to decouple them, but it only provides valid radiation patterns in the far-field and does not account for intrinsic attenuation. In this paper, we address this problem successfully, allowing for the inclusion of free surfaces in the FFS.

Jan 1, 2024

By Rakam Lama Tamang, Michael J. Byle, Stephen Ernst

"For various reasons, dredging may become necessary in front of existing bulkhead walls, either for channel deepening or for environmental remediation of contaminated sediments. The removal of sediments at the base of bulkhead walls removes support for the toe of the wall that must be assessed. Evaluation of this impact can be problematic for aging bulkheads for which no design or construction records exist. This paper will address the steps that should be taken in investigation and analysis to assure proper assessment and means to address uncertainties and gaps in information. The steps include pre-investigation data review, field inspection, geotechnical and geophysical investigation tools, parametric analysis and design tools. Examples from several bulkhead assessment projects will be provided that include a variety of conditions and tools for application. The focus of the paper will be on the integration of technologies to assess bulkhead geometry, geotechnical properties and stability, structural safety and constructability issues with removal of support, and means of temporary and permanent stabilization for environmental applications.IntroductionBulkheads and quays have existed as long as there have been waterfront activities. Some of the earliest date back to 1200 B.C.E.(Raban, 1987), however in the United States few predate the eighteenth century. Most extant bulkhead structures, and all steel sheet pile bulkhead walls date from the early 20th century or later. These structures function to protect the shore from erosion, support landside activities, and serve as place to moor and offload vessels. Regardless of the age or usage of existing bulkheads, it is essential to assess and protect them if needed where removal of soils on the water side of the bulkheads is planned to dredging.Waterfront BulkheadsExisting bulkhead structures can be classified into two types: Cantilevered, and anchored. Cantilevered walls are completely supported by the soil on the water side, while anchored bulkheads are supported both by the soil on the water side and anchorage on the land side (Figure 1). Walls may be constructed of timber, steel, or concrete. Timber walls may be lagging with soldier piles, cribbing with soldier piles, or timber sheeted such as Wakefield walls (Figure 2). Steel bulkheads are most commonly constructed using sheet piling comprised of interlocking A or Z shapes, though some historic walls were constructed with flat sheets. Precast concrete sheet piling has also been used in construction of bulkhead walls. Anchorage may be provided by steel bars or tendons attached to deadmen, sheet piling, driven piles, or earth anchors."

Jan 1, 2017

By R. Maxwell

"At Opemiska Copper Mines we have, over the past four years, operated 300 cu. ft. and 700 cu. ft. flotation cells as roughers, scavengers and cleaners and found them competitive with conventional flotation cells on a cu. ft. basis on all phases of flotation.The economics are very much in favour of the large cells for the following reasons:Power consumption is 35 to 40%, of conventional machinesMaintenance cost is about 20 to 25% of conventional machinesSpace required is about 30 to 35% of conventional machinesInstallect cost is about 40%, of conventional machinesTo put the above in more concrete terms below is what we are doing at Opemiska:1. Increasing mill capacity from 2000 to 3000 T.P.D. and will use only 5Cff, of the flotation space for 3000 tons that we used for 2000 T.P.D. with conventional flotation machines.2. Will require only 10 flotation cells for 3000 tons against 85 conventional cells for 2000 tons.3. Cells will be, one 2000 cu. ft. rougher, six 700 cu. ft. scavengers (2 banks of 3 each) and one cleaning circuit using three 300 cu. ft. cells.You will note that in this 3000 ton per day plant, we are going to have only ten cells. Had we put in conventional cells for this tonnage, we would have needed 120 cells."

Jan 1, 1970

By T N. Little

The aim of any rock breaking activity is to achieve success by developing designs that are blasting objective-specific and geology-specific, and then implementing such designs. This paper targets mining geologists with the aim of extending their knowledge of the rock fragmentation processes and providing insights to the significant relationships between geology and blasting. There are two main relationships, and if mining geologists appreciate both these relationships, then they can play a key role in optimising production. The business risk continuum is introduced to support this understanding. The first relationship is between geology and potential blasting hazards, and the operational complexity required to manage those risks. The risks associated with eight different ground types are discussed in terms of ground conditions, hazards and controls. These types are: reactive ground, hot ground, geothermal ground, fibrous ground, cavernous ground, combustible ground, pyritic ground and conductive ground.The second relationship is between the bench geology and blasting results. The blasting results discussed include: muckpile characteristics, remaining rock faces and blasting emissions. In this regard, some detailed insights and graphical examples are given for the influence of geology on blasting emissions, in particular, vibration, airblast and flyrock.A detailed description of the geological materials themselves can convey much useful information for blasting operators provided they are able to utilise this knowledge. Geologists are ideally suited to provide this description more effectively if they are familiar with the blasting process and the rock mass properties that influence blasting hazards and blasting results. It is also important to have clear statements of blasting objectives and associated operational targets, and this will maximise the likelihood of achieving the desired outcomes. The main aim of the paper is to highlight that geology is currently not fully utilised in the blasting process. In this regard, geologists are often not entirely aware of the blasting process and how they can contribute. The two significant relationships discussed above are integral parts of this process, and thus they are discussed as separate issues in the main body of this investigation.

Aug 22, 2011

By Tor Lindstad

Specific C02-emissions are given for the production of silicon-metal, ferrosilicon, ferromanganese and silicomanganese. Emissions taken into account come from reduction materials, from coke production and generation of electric energy. C02-emissions can be abated by direct and by indirect methods. A direct method is to replace fossil carbon as reduction material wholly or partially by endogenous carbon (biocarbon, charcoal). Another possibility is to produce metals by electrolysis instead of the present electric smelting furnace. Indirectly CO2-emissions can be reduced by energy recovery, thus saving coal, oil or natural gas for heat generation. Some reduction in global C02-emissions can be obtained by giving credit for the use of silica dust partially replacing cement in concrete. In addition to give an overview of possible methods, costs will be discussed.

Jan 1, 1999

By Mark Eisner

ONE'S JOB is the watershed down which the rest of one's life tends to flow write the Lynds in the first pages of their classic social study, "Middletown in Transition." Certainly engineers will confirm this statement after a check among those in their own profession with whose lives they are at all familiar. I have no hesitancy in acknowledging the truth of their observation for the men and women who are engaged in the profession of the law. It has been often remarked that American public life is overrun with members of the law profession. The highest public office in the land, that of President. has been occupied by lawyers almost to the exclusion of citizens of any of the other professions. Twenty-two Presidents of the United States out of the total of 31, were members of the bar. For the most part, members of Congress, the governors of the states, the state legislators and the mayors and other local leaders, men who occupy important positions of responsibility and public trust, have had legal training. Now this fact is no mere accident. Those who were fitted for the "job" of the practice of the law are favorably placed with respect to their participation in public life. Thus public service and public office is the watershed down which the "lawyer's" life tends to flow.

Jan 1, 1940

By K. Poorhaydari, B. M. Patchett, D. G. Ivey

In this paper, some applications of carbon extraction replicas, as samples for transmission electron microscopy (TEM), are discussed. Modern high strength microalloyed (HSMA) steels, used as structural or pipeline materials, have very small grains with substructures. Replicas used in TEM can resolve the grain boundaries and can be used for grain size measurements in cases where the small size of the grains pushes the resolution of conventional optical microscopes. The grain size variations obtained from replicas correlated very well with mechanical property variations, indicated by hardness, in the fine-grained heat-affected zone and base metal of some welded HSMA steels. Replicas are also very suitable samples for precipitate examination with analytical TEM. Advantages and limitations of the application of replicas, as well as some corrections for the estimation of the volume fraction of fine precipitates, are discussed.

Jan 1, 2005

By R. W. Huber, R. C. Wiley, V. C. Petersen

"Three arc- melted ingots, two of a t itanium-7 percent manganese all oy and the third of unalloyed titanium, were forged and rolled into 3/ 4-inch plate; comparative data were obtained on these processes. The finished plate, part of which was used by the Naval Bureau of Ordnance, was tested for mechanical and other properties.These properties were correlated with sponge purity, forging technique, rolling temperature, and cooling rate from the rolling temperature. For the alloy material, transformation data were obtained, and their age-hardening characteristics were studied. The temperature-impact relationship was established for rolled sections from all three ingots.INTRODUCTIONArc -melted ingots of unalloyed titanium and a titanium-manganese alloy were fabricated into plate under closely controlled conditions by personnel of the Metals and Alloys Section, Physical Metallurgy Branch, Bureau of Mines, College Perk, Md. This program was cosponsored by the Naval Bureau of Ordnance. Bureau of Mines interest lay in correlating the processing procedures with the mechanical properties of the finished plate.Considerable data have been published recently on constitution diagrams and properties of titanium-manganese alloys in genera1. 3/ 4/5/6/ However, little if any correlation between processing schedules and end results has been published, particularly with respect to the present commercial production of the proprietary titanium manganese alloys . Several factors in the production of titanium and titanium alloys have a pronounced influence on the physical and mechanical properties of the finished product: (1) The degree and nature of impurities in the base materials, ( 2) the amount of impurities introduced during the melting cycle and their distribution, (3) the homogeneity of the alloy, (4) forging, (5) rolling, and ( 6) final heat-treating cycles. All of these item£ are important from a metallurgical standpoint in producing the desired end properties in the metal."

Mar 1, 1955

By John H. Lichtblau

There are three parties to the oil imports controversy: the domestic oil producers, whose side has just been ably summarized by Mr. Jameson; the oil importers; and the public. Domestic producers and importers are both motivated by economic self-interests, that is by their natural and legitimate desire for profit maximization, in their respective positions. Thus, domestic producers, rightly, regard every barrel of imported crude oil (with the exception of some specialty crudes) as a displacement of a barrel of their own crude. Hence, the lower the import Level the better they like it. Conversely, U .S. refiners whose plants are located at the seaboard or at certain inland waterways generally welcome a higher level of imports because refiner profits are based primarily on the spread between the crude oil price and the refined products price, since crude oil represents by far the refiner?s largest cost factor. The relatively low cost of foreign oil means therefore higher profits to those refiners able to process such oil, This applies particularly to integrated companies whose own domestic oil production is insufficient, to meet their refinery requirements but who have developed ample low-cost foreign oil supplies.

Jan 1, 1962

By J. J. Dowd

1. The Pittsburgh bed is the most important bed in Ohio County, and virtually the entire production of coal in the county comes from this bed. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of-coal in place, are estimated at 365 million short tons as of January 1, 1954. Of this total, 356 million short tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1955

By E. A. Hewitt

This paper describing the mining practices at the Park Utah mine in the Park City district is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The Park Utah mine is situated at Keetly, Utah, about 5 miles east of Park City. The Park City district lies on the eastern slope of the Wasatch Mountains, 25 miles southeast of Salt Lake City. The district embraces a tract located between the crest of the main range on the west and the mountain meadows along the eastern foothills. The elevation of the Union Pacific Railroad station at Park City is 7,000 feet above sea level. The town and mines are served by two railroads; one 28 miles long is a branch of the Union Pacific Railroad and connects with the main line at Echo Junction, east of Ogden; the other is 35 miles long and joins the Denver & Rio Grande Western Railroad at Salt Lake City. The district and mines are also accessible by excellent automobile roads from Salt Lake City and surrounding points (fig. 1).

Jan 1, 1930

By John Birkinbine

Modern advances in practically all lines of industrial develo1)ment have occurred in such rapid succession, and have been accepted so readily as accomplished facts, that a retrospect surprises us, by showing how comparatively few of the acknowledged factors of improved conditions may be considered as old. While these advances have not been confined to any country, they have been more pronounced in some than in others, and nowhere more so than in the United States, the population of which, having multiplied nearly three-fold between 1870 and 1910, demanded a proportionately greater increase in materials, supplies, and manufactured products. It therefore appears desirable to discuss mainly conditions in the United States, as concrete evidence of industrial progress throughout the world. Looking backward for but three generations, me mar trace the introduction and developmerit of canal- and steamboat-narigation ; railroad-transportation; artificial illumination beyond that f'urnished by candles and animal-oils; quick communication by mail, and subsequently by telegraph or telephone; the manufacture of iron, beyond forms of small dimensions; the production and utilization of steel in large quantities; the economic use of mineral fuel, oil and gas, etc. The practical coincidence of the fortieth anniversary and the 100th technical meeting of the American Institute of Mining Engineers, offers temptation to recall and compare the conditions of milling and metallurgy in or about the years 1871 .and 1911. A complete résumé would cover phenomenal changes in mining-methods and equipment by which the output of individual exploitations has grown from scores to hundreds and even thousands of units in equal time-intervals. Extension of operations in depth and area, demanding machinery of great power and efficiency, high percentage of extraction, utilization of what

Jan 1, 1912

By J. A. Eisele

The Bureau of Mines is investigating the recovery of alumina from domestic nonbauxitic resources, including anorthosite. The United States has large reserves of anorthosite, but its aluminum content is less than 50 pct soluble in acid, unless a source of fluoride is added to the acid. A flowsheet that includes leaching with HCl and fluoride followed by crystallization of AlC13.6H20 from the pregnant liquor by HCl gas injection was designed. Approximately 90 pct of the aluminum values were recovered from the anorthosite when a ratio of 0.14 mole of fluorine per mole of aluminum was used. Sodium chloride is cocrystallized with the A1C13.6H20 but is removed by water washing of the Al203 product. A material balance is given based on results of laboratory studies of the unit operations.

Jan 1, 1983

By P. M. Gruzensky

A survey of the literature has been made covering the extraction of bismuth from raw materials, its separation from lead, and its subsequent refining. The use of aqueous, nonaqueous, and fused electrolytes in electrolytic refining is reviewed. This literature survey has been prepared preliminary to some proposed investigations concerning the electrometallurgy of bismuth, and, although an effort has been made to cover a majority of the applicable references, a critical review was not attempted and no assertion is made that this manuscript is exhaustive in nature. Titles of publications in parenthesis are translations from the language in which the reference was originally published.

Jan 1, 1954