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By J. R. Linney

THE Eastern magnetite industry has not failed in its contribution to the war program during the past year. Man-power shortage was the critical problem in maintaining production and for the last half of the year, owing to lack of man power, it was necessary for some mines to change from seven to six days per week schedule. At Cornwall, Pa., the mine operated by the Bethlehem Steel Co. produced approximately 2,000,000 tons of crude ore and 1,200,000 tons of iron ore concentrates, a decrease of about 10 per-cent compared with the previous year. Railroad haulage in the open-pit at this mine was discontinued, being replaced by Mack trucks of approximately 30 tons' capacity. At the Mt. Hope mine in New Jersey, the Warren Foundry and Pipe Corp. produced about 195,000 long tons of crude ore obtaining 70.000 long tons of lump ore and 35,800 long tons of concentrates. An additional 24,500 long tons of concentrates was produced from a stock pile of 47.000 long tons of crude ore accumulated during the latter half of 1943, following the fire in their old dry mill. All of this material was handled through their Brown

Jan 1, 1945

By W. Bryszewski

As a result of strategic analysis in respect of the needs for air quality management a new advanced and holistic approach to air quality management process was introduced in the North West Province (NWP) of South Africa. The process is based on the principle of co-operative management. It involves both active participation of all Interested and Affected Parties (I&AP) and the holistic approach to solving problems with the underlying principles of shared ownership and sustainable development. The process consists of the followings phases: ? Industrial process quantification ? Quantification of impacts ? Formulation of the required control measures ? Definitions of certificate conditions ? Implementation of an adequate compliance management system at company level ? Ongoing co-operative air quality and system management with the strategic objective of continuous improvements The system has been successfully introduced in the North Province and proved to be an effective management tool and aids assurance of sustained environmental ability to cope with the pressure of industrial developments. The benefits and effectiveness are discussed using Hernic Ferrochrome as an example. Hernic Ferrochrome is one of the first companies, which successfully implemented this system.

Jan 1, 2004

By Raymundo Del Carpio

El presente trabajo señala las bases que fundamentan la aplicabilidad del extracto de quebracho como depresor en el proceso de flotación, donde se realiza una combinación de un dispersante (producto obtenido a partir de extractos vegetales). También se muestra los avances sobre procesamiento de minerales con alto contenido de pirrotita. En ese sentido, se busca desarrollar una tecnología eficiente y ambientalmente limpia, considerada como una herramienta para la mejora de la competitividad de la empresa, a partir de una visión de desarrollo sostenible.

Sep 9, 2007

By Masahiko Yamaki, Takahiro Yamanashi, Hijiri Hashimoto, Hirochika Hayashi

"In this study, the authors used heat conduction analysis with the aim of quantitatively evaluating whether treating improved ground with cover soil is an effective measure for maintaining strength development in the surface layer of improved ground after constructing cement treated soil for the winter season. This report describes a simple procedure to evaluate covering soil thickness, which is necessary for the strength of the surface of cement treated soil, by using the freeze index and both the water content ratio and dry density.INTRODUCTIONIt was reported that when ground improvement using cement is performed in winter in a snowy cold region (Fig. 1 photo, Fig. 2), the uppermost 1 m of the improved ground (i.e., the cement-treated soil) tends to become prone to solidification failure from exposure to the cold air during curing (Hashimoto et al. 2006). In light of this, our research laboratory conducted unconfined compression tests using curing temperature as a parameter of analysis on improved ground toward understanding the influence of curing temperature (ambient air temperature) on the strength improvement afforded by ground improvement.The authors found that if the curing temperature is maintained at 0°C for the first 28 days after improvement and then at 5°C for the next 337 days after improvement, the improved ground is expected to have 90% of the unconfined compressive strength of improved ground whose temperature was maintained at 20°C for the first 365 days after improvement (Hashimoto et al. 2011)."

Jan 1, 2015

By T. G. Joseph, M. Welz

ABSTRACT: Joseph (2002) introduced passive seismic monitoring to measure mining equipment performance. This paper evaluates the potential of passive seismic monitoring to correlate mining equipment operation with oil sands surface response, with a mining hauler as the seismic source. When applied to moving haulers, this action–reaction approach is complex. Vibrations from on-board equipment, such as pumps and tires, dirty the signal with noise. To facilitate any correlation, the signal must be cleaned up. Existing geophysical analytical techniques were manipulated to evaluate the noise problem and to filter sufficiently to permit an evaluation of whether a mining equipment action–ground response relationshipis in fact discernable.

Jan 1, 2011

By Fred C. Bond

THEM is acute need for a method that will measure the size distribution of finely divided materials, particularly when the particle sizes are smaller than the openings of the finest screen cloth regularly available for testing. Several methods and types of apparatus are in common use, but none are entirely satisfactory for all purposes. The commonest methods are microscopic grain counts, elutriation by liquids or air, and sedimentation. Valuable results have been secured by air elutriating devices, typified by the Haultain Infra-Sizer and the Pearson Air Analyzer. These are especially useful in obtaining sized fractions that can be examined and analyzed separately. They are particularly advantageous because the sizes of the samples produced are adequate for a considerable amount of subsequent manipulation and testing. The sedimentation methods, such as the Wagner and Klein turbidimeters, and the sedimentation balance, do not deliver sized fractions, but they do provide a means for reasonably rapid comparative determinations of fineness and surface area, which are important in many industries. The sedimentation balance consists essentially of a balance pan suspended in a liquid that contains falling particles. These are weighed as they settle onto the pan, and the time rate of settling is determined. The size distribution is computed from the settling rate. The balance appears to be inherently more accurate than any of the other methods, and it has served a useful purpose in the study of numerous problems, but there have been limitations which have restricted its scope of application. Because of the essential simplicity of the method, it was felt that intensive investigation might lead to modifications that would make it a valuable tool for the operators in industries that require precise information regarding the results secured from grinding equipment. A large number of size-distribution determinations below 200 mesh were required in connection with a particular research problem in fine grinding. The sedimentation balance was used in this investigation, and a technique was gradually developed that ultimately gave good results. A serious difficulty appeared early in the work. It was discovered that less material always settled on the sedimentation pan and more on the bottom of the containing jar than could be accounted for by calculation, and also that the material that settled to the bottom of the jar outside the edges of the pan was considerably finer than that on the pan. This segregation was so great that the distribution obtained for the finer sizes was obviously very much in error; material ground to about the degree of comminution of cement might have only 60 per cent of the calculated weight actually settling on the pan, and the error increased with the fine-

Jan 1, 1939

By Kazem Oraee, Mehran Gholincjad, Navid Hosseini

"Chain coal pillars are pans of the structure of longwall mining system that play a significant role in the stability of the entries. With mechanization and developments in the various aspects of the method, higher efficiency in optimization of the design of chain coal pillars seems appropriate. In this paper the three main methods of chain pillar design, namely the empirical analytical and numerical methods arc compared. Real data from the Tabaslran coal mines have been used in order to make the comparison process reliable. It is concluded that the most apparent advantage of the empirical method is the reliability of the results while the use of numerical methods enjoys the advantage of flexibility. On the other hand the analytical methods are complex unless simplifying assumptions arc made that can substantially decrease the accuracy of result which is thought to be the main advantage of the design method. A new method is therefore introduced here that combines all of the three presently used methods and by doing so the new method has the advantages of the three while minimizing complexities and inaccuracies associated with the use of the individual methods.INTRODUCTIONLongwall mining is a high production method that can use mechanization to its full extent. Its initial development can be traced to 17th century European collieries but it was not until the second half of the 20th century with the development of self advancing support systems that the method gained popularity in the USA (Oraec. 2001). During the last decade, the production of longwall faces has increased significantly (Peng. 2006). The ability for mechanization along with good safety condition is the main reasons for such development. In the longwall mining method a good design for panel and entries on both sides, are two essential parameters. In this method, the thickness of overburden (depth of mine) nom1ally ranges from 60 to 20 m (197 to 2.7 9 ft) (Hartman, 2000) and with increasing mine depth designing for stabilizing the entries on both sides of the panel become more difficult. Thus, for safety and stability the size of chain pillar must increase. This causes the overall coal recovery to decrease and increase mining costs per ton. As such wide pillars hinder the air flow and hence ventilation costs increases too. Therefore with accurate identification of loading conditions and stress analysis. pillar that are a minimum size and sufficient safety factor are carefully designed."

Jan 1, 2010

By Lewis M. McNay

Description of methods employed and cost data are given for surface-mined land reclamation in Moraine State Park, Butler County, Pa. This project was conducted under the authority of the Appalachian Regional Development Act; a total of 177 acres of land was rehabilitated for specific land use purposes. The use of large equipment expedited the project work, and similar results could be anticipated on similar reclamation programs.

Jan 1, 1970

By Ellie Condolios

Hydraulic hoisting offers a number ~f attractive features over conventional hoisting methods: small shaft space requirements; great flexibility of layout, including pick-up or delivery of the material at points distant from the mine shaft; low investment and operating costs. However, limited practical experience with this type of hoisting dictates that careful design and, frequently, extensive testing be done by competent engineers before large-scale installations are built. This paper covers the following: basic laws and design criteria for hydraulic hoisting installations; a description of a coal hoisting installation which has been in industrial operation since 1960, with a vertical lift of 600 feet and an annual capacity of 500,000 tons of -3 ~-in. coal; and a tentative appraisal of the process, including cost estimates. THE transportation of solids in water flowing through a pipe-line has, for a number of years, been common practice in dredging, public

Jan 1, 1963

By R. L. Grayson

In 2010, MSHA began holding hearings on a new coal mine respirable dust rule, which proposes a 1.0 mg/m3 standard, a separate 0.1 mg/m3 quartz standard, and the use of single-shift samples for compliance. Small mines largely comprise the ?hot spots? where dust diseases of the lungs increased dramatically over the past decade. This paper presents findings on the feasibility of small mines? compliance with the proposed new 1.0 mg/m3 standard. It gives probabilities of noncompliance by MSHA district, seam height, and selected ?hot spot? counties. Because silicosis and respirable quartz dust appear to be the primary issues related to a recent doubling of the prevalence of dust diseases of the lungs, multiple regression models for prediction of the average total quartz content of compliance samples are given. These findings have significant implications on the need for better dust control methods.

Jan 1, 2012

By S G. Bergdahl

Underground mining in Sweden is today characterized by mechanization and automation, owing to the rising cost of labour. Drilling in drifts and tunnels is still essentially done with jackleg drills, but rigs wh1ch make it possible for one man to operate two or more drills are now frequently used. Large jumbos for longhole drilling, with two drills operated by one man, are used, especially in sub-level caving. A special drill-rig for drilling through overburden and blasting without removing the overburden has been successfully used in canals and also in ports, where blasting is per-formed under water. The increased use of mining methods based upon long blastholes is a result of the development of equipment for drilling long straight holes. The most common mining method in Sweden is sub-level caving. Extensive research, with model tests, has been carried out in order to determine suit-able dimensions of drifts, sub-levels and drilling patterns. The results have been tried in practice and have given increased yield and less waste rock in hoisted ore.

Jan 1, 1963

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 Margot Panta, Diego Guevara, Miriam Torres, Irayda Salinas

Los bofedales son humedales altoandinos considerados ecosistemas frágiles por la Ley General del Ambiente de Perú - Ley N° 28611. Este trabajo evalúa la fragmentación y conectividad de 20 bofedales ubicados en el distrito de Huachocolpa, departamento de Huancavelica; los mismos que abarcan un área total de 111.9 ha, con un área promedio de 5.595 ha por parche, con el fin de contribuir al mejoramiento de planes de manejo de la biodiversidad (fauna y flora) altoandina y facilitar la recuperación de dichos ecosistemas.

Sep 20, 2019

By Anthony F. G. Lucas

BORN on Sept. 9, 1855, in the city of Spalato, Dalmatia. Austria, Antonio Francisco Luchich was the son of Francis Stephen Luchich, a prosperous shipbuilder and ship-owner of Lesina. His mother, Johanna Giovanizio, was known to the people of Trieste as a woman of unusual learning and piety. After receiving his high school training in Trieste, Antonio Luchich entered the Polytechnic Institute at Gratz in the year 1875, graduating two years later as an engineer. He then entered the Naval Academy of Fiume and Pola as a Midshipman, receiving his commission as a Lieutenant in 1878. In 1879, then 24, Antonio Luchich obtained a leave of absence from the Austrian Navy and came to Saginaw, Mich., to visit an uncle. He remained in this country and on May 4. 1885 at Norfolk, Va.. he became Anthony Francis Lucas. an American citizen.

Jan 1, 1945

By Graham W. Marks

The general positions of the absorption maxima of aqueous solutions of the violet and green isomers of chromic sulfate the visible spectral region have long been known, but, to the knowledge of the writer, no comprehensive studies have ever been made. To gain further knowledge concerning these inorganic complexes and to investigate the possibilities of developing an analytical method for determining the concentrations of the violet and green isomers in a mixture, a more complete investigation was made in the spectral range from 325 to 850 millimicrons.

Jan 1, 1951

By Philip J. Guerney, S. O’ Leary, André R. Laplante

"Concentration of dense mineral phases (s.g. greater than 7) for characterisation of individual particles and mineral grains by electron microscopy is a well established technique for the detection and characterisation of valuable mineral phases. This presentation describes the type of data that can be generated when both the concentration and characterisation steps are carried to higher levels than typical. The concentration step is the gravity recoverable gold (GRG) protocol that has been used for over 100 ore samples. This protocol yields three concentrates that represent three progressive degrees of grinding and liberation. Three ore samples were subjected to the GRG protocol and three size classes of each concentrate were characterised using the mineral liberation analyser (MLA), an automated, EDX-based tool. This presentation briefly presents GRG and MLA technology, and then focuses on the results obtained: photos, images and databank, the latter used to evaluate the extent of particle liberation and particle shape.INTRODUCTIONThe practice of gravity concentration prior to characterization of mineral samples using electron beam microscopy is solidly established. Typically, a dense liquid such as tetrabromoethane (density: 2.97 g/cm3) is used to reject the light phase, typically carbonates and silicates. The heavy phase, mostly sulphides, oxides and precious metals, is then mounted in a polymer matrix and examined using beam microscopy.Both the pre-concentration and the sample preparation/examination steps have seen significant advances over the past ten years, but are not without problems. A major issue of preconcentration is that most dense liquids used are toxic, tetrabromoethane being a prime example. More recently, a dense liquid with little or no toxicity (sodium polytungstate, distributed by Sometu Inc.) has become commercially available, but its use is limited to relatively low s.g. splits around 3 g/cm3. Dense liquids are viscous, and their use is limited to particles coarser than 37 µm, although centrifuge separation can probably lower this limit to around 10 µm. Magnetogravimetric separators can achieve much higher specific density cuts, but upgrading below 100 µm or in the presence of magnetic minerals remains a problem. The use of centrifuge separators such as the 3-in Knelson Concentrator (KC MD3) or the Falcon 4-in SB (SB4) is particularly attractive since these units can easily process large masses (by laboratory standards) and achieve a cut density well above those of dense liquids."

Jan 1, 2003

By M. J. Lawrence

Independent natural resource Valuers are an essential link between miners and mineral explorers on the one hand and the finance industry on the other. Investors (and regulators) expect the mining and financial industries to be vigilant against the use of inappropriate methodology or use of illogical steps within the chosen valuation method. The Australian Corporations Law generally requires an Independent Expert Report to support mergers and takeovers (as well as for capital raising activities). The introduction of the VALMIN Code (1998) by The Australasian Institute of Mining as Metallurgy, has meant that such Reports, when prepared in compliance with it, are now much more comprehensible and reliable than before. This is because the key requirements of the Code are for transparency and materiality in the Technical Assessment and Valuation Reports prepared in connection with the transaction involved. Transparency is particularly important because it allows the reader to identify and understand the assumptions made to derive a value and to then form a view as to the reasonableness of the result. Even though many elements of resource asset valuation practice are undeniably subjective, there must be some basis of objective rationality to it. Where the reasoning is patently illogical or the inputs are chosen to achieve a particular result, the estimated value must be viewed as virtually worthless. Experience, qualifications, competence and repute are the hallmarks of a professional technical auditor and valuer.

Jan 1, 2000

By M. Clair Smith

This report is one of a series describing exploration, development, mining, and processing of mineral deposits in the United States. The reports are prepared and published by the Bureau of Mines in cooperation with various mining companies The purpose of the reports is to promote development and conservation of our natural reserves by disseminating technological information on mining and milling procedures and related practices at operating mines. Simplot Silica Products, Inc., mines and processes a friable silica sandstone. The finished products are sold for use in glass manufacture, foundries, chemicals, and special applications.

Jan 1, 1959

By Edwin Berry

THE consideration of the present value of a mine is of great importance when planning for the operation of a property,, and it is particularly so in the case of mines that have large ore reserves. At various times during the past 15 years, the writer has had occasion to make rather thorough studies of the subject, and has been greatly impressed by certain important points which these studies have brought out, points which, though they may be well known, are often lost track of in the rush to obtain low mining costs and high daily tonnage output. . It is the object of this paper to present briefly, and in a general way, some of these points, and especially those which have to do with the relationship which (1) ore reserves and plant capacity, (2) grade of ore mined, and (3) ore losses in mining, bear to the present value. Present value, sometimes called present worth or actuarial value, means the value today of the future earnings of an enterprise. Great industrial, manu-facturing or railroad enterprises, if properly handled, go on indefinitely and their value is directly dependent on their estimated annual earnings. Mines, or oil properties, on the other hand, have an earning capacity only until the ore or oil is exhausted, and their present value is dependent not only on their annual earnings but also on their life, which is the length of the period over which they can produce at a profit. A mine, or an oil property, is a "wasting asset," while an estab-lished manufacturing business is not, or should not be. In other words, the present value of a mining property. represents a sum of money on which there could be paid from operating profits a determined rate of interest, say 8 per cent., and in addition an amount which, if invested at compound interest as received, would at the end of the life of the mine pay back the present value. In his "Wealth and Income of the American People," Walter Renton Ingalls says: "The fundamental principle of mine valuation is the present worth of an annual dividend accruing during the period of years corresponding to the life of the mine."

Jan 7, 1922

By D. J. Bauer

This report covers a phase of an extraction project carried out as part of a research program on rare-earth technology. The current project--the production of pure cerium compounds--is an intermediate step between ore processing and metal reduction. In this connection, a study on a separatory-funne1 scale was made on nonreducing extractants for recovering cerium (IV) from tri-n-butyl phosphate (TBP) and of methods for recovering the cerium nitrate from the strip solution. Dilute sulfuric acid was found to be 100 percent effective in stripping cerium (IV). Several precipitants were effective in recovering the cerium from the strip solution, and ethanol was especially promising. A scaled-up investigation was made into the use of spray-tower type equipment to perform the function of extracting, washing, and stripping. This equipment, referred to as the pressure-bubbler, utilized the system developed on the separatory-funnel scale. Feed solutions were prepared from a bastnasite concentrate by two techniques. Of these, the sulfated bastnasite solution was most successful, resulting in 86-percent recovery of the cerium at 99.7+-percent purity.

Jan 1, 1959