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By Fred Hellmann

IT IS hardly to be doubted that the opportunity within the grasp of the mine manager for beneficent and helpful action in relation to young engineers seeking employment under him is very broad and very big. It is my experience that a manager usually has a strong inclination to help along those who have chosen the career which he has selected for himself, and to aid them and support them as their steps tread the paths which his own feet have previously followed. He has .a strong sympathy for them in their efforts, he almost yearns to shield them from the mistakes into which he himself fell, and to assist them to avoid the pit-falls of which he knows by bitter experience. Yes, this tendency and inclination is strongly developed in most managers, and they would welcome the opportunity of extending the helping hand, if they knew precisely how best this could be done.

Jan 5, 1923

By A. R. Troiano, E. A. Steigerwald, F. W. Schaller

The initiation of localized cracking in hydrogenated high strength steel was dependent on the developmeni of a critical hydrogen conceniration and relatively insensitive to the magnitude of the applied stress. The stress was believed to influence the deluyed failure process by providing the means for grouping the hydrogen. On the basis of an assumed distribution law the observed changes in the lower critical stress as a function of notch acuity, yield strength, and temperature were predictable over a significant range of these variables. THE phenomenological characteristics of delayed failure in high-strength steel have been comprehensively investigated and the behavior has been attributed to the strong embrittling action of hydrogen.1-3 Delayed failure or, as it is also termed, static fatigue, is the most sensitive means of detecting hydrogen embrittlement since it allows the maximum time for hydrogen diffusion during a test.3 The nature of delayed failure cail be aptly described by four parameters which are schematically depicted in Fig. 1. The upper critical stress corresponds to the rupture stress in a conventional notch tensile test. The lower critical stress or static fatigue limit is the stress below which no delayed failure will occur. The incubation period is the time required for the formation of the first crack and the fourth parameter is the failure time. An increase in hydrogen content, notch acuity, or strength level of the material increases the susceptibility for delayed failure by decreasing the lower critical stress, the incubation period, and the time to failure.lY3 A decrease in test temperature prolongs the incubation period in accordance with the lower diffusion rate of hydrogen, and also de-

Jan 1, 1961

The compliance sampling method for coal mine dust in the United States has not changed appreciably in the last 30 years. A call for more frequent sampling with immediately available results is leading to new instruments that may supplement or replace the existing sampler. This report discusses two such instruments that provide immediate results of dust levels. The first, called the Respirable Dust Dosimeter (RDD), is designed to supplement the existing U. S. cyclone compliance sampling method. It uses the pressure drop across a filter to provide an inexpensive screening type of measurement. The RDD has been tested in the laboratory and a limited number of coal mines. Side by side testing has compared the RDD performance with personal coal mine samplers in triplicate area sample measurements. Results show that the differential pressure of specific filtration media can be an effective surrogate for respirable mass. Data show that there is a dependence on coal type and an effect of relative humidity. There also appear to be two distinct responses related to coal type. For specific coals the coefficients of determination, R2, are better than 0.9. For general use the detector tube, using laboratory generated calibration curves, can be used to estimate respirable dust levels. However, a calibration to a specific coal type may substantially improve the accuracy. Another sampler in development is called the Personal Dust Monitor (PDM). Designed to give compliance quality accuracy, the PDM uses the frequency change of a vibrating element to measure dust and give immediate feedback of results. Results of laboratory comparison of the prototype PDM sampler to personal gravimetric samplers indicate R2 values of better than 0.99 for three different coal types. Work is in progress to package the components into a person-wearable unit combined with a cap lamp system with a total projected weight of less than 1.4 kg (3 lbs).

By J. Schleifer

On short term, planning techniques require more details to ensure feasibility, giving importance to operation constraints and use of available resources. In GUEMASSA (Morocco), the ore mass is mined by cut-and- fill method. Correct organization requires to forecast a few weeks ahead the schedule of blocks to be mined, in order to respect ore quantity and grade constraints. While operating constraints are tackled, feasibility is assumed with an average production capacity suggesting that resources will be available. In ST-SALVY (France), scheduling operations is not possible if not considering account resource allocation. In any stope within the vertical vein zinc deposit, the cut-and-fill method enables to mine each horizontal slice according to various strategies, de- pending how to use manpower and equipment, and selecting among predefined scenarios known as realistic. For KOFFIEFONTEIN (South Africa), the kimberlite pipe is mined by a sub-level-stoping method. To achieve the production target, precise organization over one month is obtained, using on& resources when available and respecting all mining rules. This combined operation scheduling and resource allocation is called sequencing. While following the BONANZA concept, providing a planning- retrieval process, sequencing offers more. Very detailed, it is possible to check the impact of resource parameters and mining rules. The sequencer, like a simulation platform, enables expertise. Each sequencer must be tailor-made to fit to each specific mine. The next challenge is to produce a generic environment.

Jan 1, 1996

By V. de Ruiter

In the northwestern part of the Netherlands lies the deepest solution salt mine in the world. The company operating the mine is Frisia Zout bv (part of the K+S group). Extracting the NaCl from caverns at a depth of nearly 3000 m has a lot of challenges. Continuously monitoring, among others, the flows, pressures and salt concentrations is necessary to safely and economically mine the salt. A system has been set up at Frisia to be able to monitor the data from a distance. Data has been put in graphs to monitor the trends daily. All gauges are also continuously monitored to maintain accuracy. With this system a better understanding of the mining process has been made and has led to many optimizations.

Jan 1, 2008

By D. M. Beeson, G. D. Ortloff

Water-propelled banks of carbon dioxide recovered both high- and low-viscosity crude oil substantially in excess of that recovered by water flood in linear flow model experiments. The increase in oil recovery is explained by oil swelling and viscosity reduction. Additional oil was recovered by solution gas drive at the end of the carbon dioxide floods when the model systems were depres-sured. This study was an investigation of the use of a water-driven carbon dioxide bank to recover crude oil. Techniques involving the injection of carbon dioxide have aroused con-siderable interest in recent years among methods considered for increasing oil recoveries. A number of investigators have studied the process in the laboratory1-' and in the field.7,5 Laboratory studies referenced indicate that carbon dioxide in conjunction with water flooding recovers more oil than does water flooding alone. These re- ports diverge widely, however, in stating magnitude of improvement. We believed that a water-driven carbon dioxide bank would increase recovery of crude oils by two mechanisms: viscosity reduction and oil swelling. Due to reduction in the oil viscosity caused by solution of carbon dioxide, displacement efficiency should be improved. In addition, the residual oil should be highly swollen by the carbon dioxide held in solution. Thus, the final residual oil saturation, in terms of stock-tank oil, would be lower than in the absence of carbon dioxide. To test this hypothesis, experi-

By R. Marandi

The effective removal of heavy metals from aqueous wastes is among the most important issues for many industrialized countries, How ever biosorption, i.e. the uptake of heavy metals by non- living biomass, has gained increased credibility during recent years. Biosorption of Cr(VI) from aqueous solution, on pretreated and immobilized Aspergillus niger was investigated in a batch and countinuous reactors. A.niger biomass pretreated by boiling in 0.5 N NaOH solution for 15 min, exhibited higher Cr(VI) removal capacity than autoclaved biomass. The optimum adsorption pH value observed for Cr(VI) ions was 2. The Cr(VI)removal rate increased with a decrease in pH. The influence of contact time, pH, Cr(VI) concentration, biomass concentration and temperature on Cr(VI) removal were also evaluated. Biosorption of Cr(VI) on pretreated biomass followed the Freundlich and Langmuir adsorption models.In this study A.niger biomass was immobilized in Na-alginate matrix. The biomass beads packed in a column were able to remove metal ions.In this study we used two different flow rate in a column, 1.5 mL/min and 3 mL/min.The breakthrough data obtained for Cr(VI) was adequately by the Thomas and Yan models and the adsorption capacity of the biomass was found to less than the adsorption capacity obtaind in the batch study. When the beads containing biomass become saturated with metal ions, the adsorbed metals were eluted using 0.5 N NaOH solution. Therefor nearly 90% of Cr(VI) was desorbed by NaOH solution.

Jan 1, 2014

By C. F. Tolman

Discussion of the paper of C. F. TOLMAN, JR., presented at the New York meeting, February, 1916, and printed in Bulletin No. 110, February, 1916, pp. 401 to 433. Louis C. GRATON, Cambridge, Mass.-Of particular interest at this time is any paper that deals with chalcocite, the characteristic product of secondary enrichment and the copper mineral of greatest commercial importance, and that seeks to aid in the distinction between primary and secondary chalcocite-a distinction of much scientific and practical importance but one which thus far it has proved difficult to draw. The present paper on this subject by Professor Tolman, like the ,many preceding it which he and his colleagues at Stanford have published in the last couple of years, contains much of interest and suggestiveness. Without endeavoring at this time to review or comment upon Professor Tolman's conclusions in detail, I may say that many of them are in accord with the findings that my associates and I have been accumulating in the course of studying secondary enrichment in many of the copper deposits of the country. On the other hand, it goes without saying that in this comparatively new field of research or, at least, a field in which

Jan 5, 1916

The Government of New South Wales has granted approval for Hunter Valley Aluminium Pty., Ltd" and Alcan Australia Ltd. to proceed with the building of an aluminum smelter at Lochinvar and the expansion of a smelter at Kurri Kurri. Construction of the smelters is expected to start as soon as the consortium is finalized in early 1982. The smelters are part of a plan to increase Australia's aluminum capacity fivefold to 1.5 million tons by the mid-1980's. CHILE Construction of a $61 million lithium carbonate plant in northern Chile will be started in early 1983 by Sociedad Chilena del Litio Ltdao Production is scheduled to begin in 1984 with an initial capacity of 6,350 tons of lithium carbonate produced from a brine deposit. The firm is owned 55% by Foote Mineral Company, of Exton, Pennsylvania, and 45% by Corporacion de Fomento de la Produccion-CORFO.

Jan 1, 1982

By David Green

"This paper describes Outokumpu's Tank Cell concept using the unit reactor principle and operating experience gained in various applications. Presently the tank cells used range in size from 35 t pilot size to 100 m' (3500 cuft). The paper discusses operating experience and results from commercial installations in copper and zinc rougher and cleaner services.The key feature of the Tank Cell described is the effective control of the froth phase and resulting possibility to operate on an improved grade recovery curve by manipulating the control variables."

Jan 1, 1995

Jerome L. Boyer, Reading, Chairman; William L. Sheafer, Pottsville, Secretary ; Levi Quier, Reading, Treasurer; Robert Allison, Port Carbon; James Archbald, Jr., Pottsville; William Atkins, Pottsville; D. P. Brown, Lost Creek; William McH. Boyer, Rending; Albert Broden, Reading; George Brooke, Birdsboro; Frank Carter, Pottsville; H. P. Cooper, Pottsville ; J. H. Carpenter, Reading; E. S. Cook, Pottstown; B. Halberstadt, Pottsville; Hakon Hammer, Pottstown; J. Hartshorne, Stowe; M. P. Janney, Pottstown; R. C. Luther, Pottsville; N. Muhlenberg, Reading ; W. H. Morris. Pottstown ; George L. Norris, Reading; G. H. Potts, Pottstown ; H. Potts, Pottstown; S. M. Riley, Ashland ; J. S. Robeson, Pottstown ; Jas. P. Roe, Pottstown; A. W. Sheafer, Pottsville; Heber S. Thompson, Pottsville; Bard Wells, Pottsville; E. C.Wagner, Girardville; N. B. Wittman, Birdsboro. Reception Committee.— George Brooke, Chairman; Robert Allison, J. H. Carpenter, Edgar S. Cook, R. C. Luther, W. H. Morris, H. S. Thompson. Hotel Headquarters.—The Neversink Mountain Hotel, near Reading, Pa. All sessions were held in the hotel. The opening session was held on Tuesday evening, October 11. Mr. Jerome L. Boyer, Chairman of the Local Committee, called the meeting to order, and introduced Mr. John F. Daniel], Jr., VicePresident of the Reading Board of Trade, who delivered an address of welcome, in the course of which the industrial and commercial importance of the city was effectively outlined by skilful use of the statistics of leading branches. From this statement the following particulars are condensed for preservation: The Board of Trade has about 300 members. The annual value of the manofttctures (taking mainly the figures of 1891) is as follows: Iron manufactures, about $16,000,000 (including boilers and flues, $323,000; hardware, locks and butts, $1,650,000; pig-iron, wrought-iron pipe and machinery, $8,400,000; beams, bridge-work and steel, $4,000,000; bolts, nuts, rivets, etc., $1,000,000; stoves, $659,000); silk and cotton goods, $1,725,000; boots and shoes (one concern only), $150,000; ropes and cordage, $600,000; fire-brick, terra-cotta and glass, $320,000; wool and fur hats, $3,000,000; cigars (105 millions), upwards of $3,150,000. The street and elec-

Jan 1, 1893

By Bryon Cerklefskie, Michael Schulte

"This case study explores the usage of polymer ducting as a replacement to curtains and FRP for face ventilation in two coal mines. There are two mines looked at, one is the highest elevation underground coal mine in North America, the other is the gassiest mine in North America. The paper details the trials of both mines switching from FRP and curtain respectively to polymer ducting. The results discuss the ability for the mines to not only achieve consistent airflows and keep them in compliance but the unexpected positives. Mine A was allowed to do longer cross cuts due to increased air volume at the face. This drastically cut their costs of mining down due solely to modification of the ventilation cycle. Mine B saw economic benefits due to longer cuts between place changes. Both mines have documented lower dust, methane, noise, and improved wear and tear on their equipment as a result.INTRODUCTIONThe emergence of longwall mining in underground coal operations has resulted in new ventilation challenges. Numerous production crews strive to complete their development sections with enough time to adequately prepare for the upcoming longwall panel. Continuous miners will cut out two or three entry development sections per their ventilation plan, that is approved and controlled by MSHA (Mine Safety and Health Administration), which will drive amount of footage that can be mined at a time prior to installing roof support. At this moment the continuous miner, hereafter referred to as the CM, will back out of the entry and moves to the second entry to complete a similar cut. Typically, a roof bolter crew will pull in to the finished cut section and install ground support. This is called a place change style of production coal mining. There is an alternate method that includes a miner/bolter combination as well but that was not featured at either test site in this case study. Ventilation has to be provided to sweep the working face of each entry to control dust and gasses. Each task will have an MSHA prescribed ventilation requirement dependent on the dust levels and methane emissions of the rock for that particular mine. The CM, roof bolting and unused headings will each require constant ventilation but at different volumes. Since each working face is changing throughout the mining cycle the ventilation requirement in a working heading is never static and is changing with the working task.Traditional Ventilation ControlsTraditionally face ventilation for coal mining operations has been completed thru the usage of a curtain system and\or using auxiliary fans and ventilation tubing. Room and pillar mining systems typically utilize curtain systems, which use curtain walls that are installed by the miners by erecting wood framing and covering it with brattice curtain. This splits the drift width to allow fresh air to sweep the face and take the contaminated air and dust behind the curtain to the ventilation exhaust\return area of the mine. This method is difficult to adjust the airflow from entry to entry during changing cycles and requires that a wider drift is mined out in order to have enough room for the brattice wall. In operations that require roof bolting, this method limits the length of the cuts from the CM prior to advancing and can lead to not providing enough ventilation to keep dust and methane levels below compliance requirements."

Jan 1, 2019

By Frigyes Egerer, Pál Bárczy

Introduction Charles III, Holy Roman Emperor and King of the Austro-Hungarian Monarchy, established one of the first mining schools in Europe on June 22, 1735, in Selmecbanya (Schemnitz in German and Banska Stiavmica in Slovakian). The old city, built around the ancient gold mines, is shown in a contemporary engraving in Fig. 1. Charles' historical decree consisted of 13 chapters and included: the deed of foundation, the definition of grants, instruction for educational policy and curriculum, disciplinary rules, and the appointment of personnel. The first professor of the school, Samuel Mikoviny, gave his first lecture the same year, in December 1735. The 250th anniversary of the establishment of the School of Mines was celebrated Sept. 2-4, 1985, in Miskolc. It was attended by representatives of other Hungarian and of several foreign technical universities. A silver medallion (Fig. 2) was issued to commemorate the occasion and a series of lectures

Jan 6, 1986

By Wallace Thorneycroft

This paper by Mr. Thorneycroft, Past President of the Institution of Mining Engineers (Great Britain), and chairman of its Subsidence Committee, is a valuable contribution to the assemblage of data on ground movement and subsidence from coal mining. It deals with the effects of advancing longwall, a method almost universal in Europe but as yet little used in the United States outside of Northern Illinois and in a few scattered places elsewhere in thin coal beds, as in the Lexington field, Missouri. Canon City field, Colorado, and the Birmingham field, Alabama. Although by advancing lougwall, a maximum recovery of coal is obtained and it has to be employed where there are weak shale roofs, especially in deep mines, it is a more expensive method of operation unless the mining conditions are suitable, which is unusual in the United States. On the other hand, there is a growing use in this country of what is essentially retreating longwall, with an approximately straight break-line as described by Rayburn.1 With this method, in which the pillars are substantial, it was shown that the ground movement effect is practically identical with that of advancing longwall, hence the value to mining engineers of the precise data given by Mr. Thorneycroft. His study is unusual in several respects; it deals with conditions connected with the mining of a coal bed 20 in. thick, about 490 ft. below the surface, over a mined-out area in a 5-ft. bed about 90 ft. below, which had been mined about 12 years earlier. Both mines passed under Plean House, a building of massive cut stone construction built over a century ago, in which Mr. Thorneycroft resided throughout the under-mining period. Slight cracks opened in the walls as the longwall face approached the house in mining the upper seam, and closed after the face passed and subsidence took place. In the northwest wall, the last wall the face passed under, some stone blocks were broken, which was attributed to a strike period when the advance of face came nearly to a standstill. Other than this there was no perceptible permanent damage, as indicated by the photographs taken by the undersigned in 1923 (Figs. 1 and 2). Mr. Thorneycroft used a novel means of studying the successive positions of the corners of the building: he hung plumb bobs from the eaves and traced the paths of the respective plumb bob points on level surfaces. The angles made by the house walls with the plumb bob lines gave measures of the slope of the subsidence wave at the respective points. A slight upward wave was indicated by the surveys ahead of the subsidence, which would appear to be due to a tilting over of the massive sandstone stratum in the roof measures near the surface, the edge of the coal face acting as the fulcrum.

Jan 1, 1931

By Yves Lizotte, Malcom Scoble, Pierre Michaud

The concept of optimum fragmentation in surface mining operations, i.e. the degree of fragmentation to which corresponds the lowest overall associated costs of drilling, blasting, loading, haulage and crushing, was developed more than thirty years ago. Recent field investigations using novel technologies, which have been completed by ICI Explosives Canada and by others, indicate that this ultimate goal of optimum fragmentation is closer to becoming reality.

Jan 1, 1997

By Patrick R. Taylor

Coatings of TiCIFe have been produced by Reactive Plasma Spraying using ilmenite ore concentrate as the feedstock powder and methane as the reactive gas. A free energy minimization analysis of the ilmenite-methane system is presented. The coatings have been characterized by x-ray diffraction and SEM. The microstructure of the coatings indicates good interparticle cohesion. The composition of the coating is deficient in iron compared to the initial Fe to Ti ratio found in ilmenite.

Jan 1, 1998

By P. B. Altringer

The Bureau of Mines conducted laboratory tests to develop a process for recovering a marketable grade of tungsten from the brine of Searles Lake, Calif. The brine contains only 56 parts per million of tungsten (70 ppm WO3). Using ion exchange resins synthesized by Bureau chemists, 98 percent of the tungsten was extracted from the brine and 92 percent of the tungsten vas recovered as a marketable iron-tungsten concentrate containing 44 percent tungsten as tungsten trioxide. Although major technical problems have largely been resolved, research is progressing to escalate testing in a process investigation unit to provide more reliable data for an economic appraisal.

Jan 1, 1978

By Ergin Arioglu, Werner Burger

"SUMMARY The Istanbul Strait Road Crossing Project includes a 3.34 kilometer subsea tunnel excavated by TBM with an excavation diameter of 13.71 m. The tunnel will incorporate two road decks, each employing two traffic lines and shoulder with the daily capacity of 100,000 light vehicles. The tunnel alignment crosses full face rock sections with heavily fractured zones due to tectonic events as well as a long central stretch of difficult mixed face and very variable soft ground conditions. The demanding ground conditions and the large diameter in combination with realized face pressures well above 10 bar required a highly specialized and well adapted TBM. The paper describes the project challenges and the related technical solutions incorporated within the TBM design as well as the real site experience. INTRODUCTION In 2013, a 13.71 m diameter Mixshield was manufactured in Germany for the Istanbul Strait Road Crossing Project. The delivery of the TBM in late 2013 was a major milestone for the Istanbul Strait Road Crossing Project, also known as the Eurasia Tunnel Project. The Eurasia Project (www.avrasyatuneli.com.tr/en) consists of a 14.6 km route including a 5.4 km tunnel segment in its central part crossing the Bosphorus. The 3.34 km subsea section of the tunnel was excavated in closed mode using a Mixshield TBM. The remaining tunnel length is constructed by sprayed concrete lining (SCL) method followed by a cast in place (CIP) lining or by cut and cover (CC) structures for the TBM transition boxes (Figure 1, right). Other project sections on the European and Asian side consist of upgrading and widening surface access roads towards the tunnel. Conceptual ideas of connecting Asia with Europe via a tunnel crossing the Bosphorus have been around for an extended time and only became realistic towards the end of the 20th century based on significant technical developments in mechanized tunneling. Feasibility studies for a new Bosphorus crossing in 2003 and 2005 confirmed and suggested a road tunnel in its present alignment as the preferred solution. Following an international tender process the Ministry of Transport, Maritime Affairs and Communications of Turkey assigned ATAS, a special purpose company formed by Yapi Merkezi (Turkey) and SK E&C (South Korea), to design, build and operate the Eurasia Tunnel Project. The Implementation Contract was signed in February 2011. In 2012, Herrenknecht AG was selected as the supplier for the 13.71 m Mixshield TBM."

Jan 1, 2016

By Neal P. Cochran

The United States is faced with increasing demands for electricity, coupled with continuing demands for crude oil and gas. Superimposed on these' national requirements are our national requirements for clean air and elimination of thermal pollution of our rivers. From the coal viewpoint, this situation is complicated still more by the rapid advances in nuclear power. In this paper, I hope to show a way to use our Western coals as a solution to this involved national problem by producing: 1. High quality crude 2. Low cost power 3. Economic byproducts We could expect these products to be made at one site in an integrated plant that would mine (extract) coal, process it, and convert it to electricity. Perhaps the most important attribute of the plant is its reduced water requirement and the elimination of air pollution from the power cycle. Quite logically, such a plant would probably recover valuable byproducts, such as pipeline gas, sulphur, cement, aluminum, and the like. Although the plant projected in this paper is a conceptual one, it is based on work now underway by Government and industry. Prediction of the future is a most hazardous occupation, but plants such as the one projected are based on current knowledge and can be expected to reach commercial operation in the near term future.

Jan 1, 1967

By W. P. Campbell

Introduction OWING to the necessity of curtailing the length of this paper, nothing like an exhaustive treatment of the subject will be attempted. Instead, merely a few aspects will be considered, viz., water trouble in wells, sampling of waters, analysis, methods of reporting analysis, and the comparison of a few typical waters. The waters discussed will not be confined to those occurring in areas where oil or gas has already been found, but will include samples from areas in which drilling is being carried on in the hope that oil or gas may be found, i.e., from unproved fields. The Water Problem The problem of dealing with water encountered in oil and gas producing areas has engaged the attention of petroleum engineers from the early days of the industry. Water was not always considered a menace to oil sands; indeed, a certain amount of it was considered beneficial in some areas, but if such exist today they are very exceptional. In some fields, the problem is more acute than in others, and at times has baffled all attempts to solve it satisfactorily. Wells have been brought-in with promise of good production, but after a brief period have 'gone to water'. Whether ?it has always been a case of poor engineering in the form of unsuccessful water shut-off of 'top' or 'bottom' water, or because 'edge' water was present and water and oil were in such close contact it was impossible to remove the one without the other, is hard to say.

Jan 1, 1929