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By F Wu, H Wang, W Chen

A pressurisation method with multiparallel fans has been adopted at HongLiuLin Coalmine to control the significant external air leakage through the goaf area of coalface 15207. Potential damaging effects of large external air leakage on a coalmine’s ventilation system are analysed according to the current air leakage status caused by the exploitation of shallow-covered coal seams. The use of pressure balanced ventilation to prevent external air leakage through goaf areas is introduced. The calculation of ventilation network of HongLiuLin Coalmine shows that the air resistance of an external air leakage branch through a goaf area and the air pressure drops from the intake slope to the working face can be adopted to determine the values of pressure to be increased by regulating fans and airflow controlling parameters of regulators. By investigating airflow requirements of the pressure-balanced area as well as the performances of the auxiliary fans currently used in the coalmine, the number of pressurisation fans needed is fixed. The expected result is achieved after the pressurisation method has been carried out, which can be helpful for other coalmines to handle similar problems.CITATION:Wu, F, Chen, W and Wang, H, 2015. Multiparallel fan method to prevent significant external air leakages through a goaf area of a shallow covered coalmine, in Proceedings The Australian Mine Ventilation Conference, pp 267–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By P. J. van Staden

Several differences exist between the columns used for laboratory simulations of heap leaching and commercial heaps. Column walls support part of the weight of the ore and restrict the particle packing arrangements. Columns are typically of a diameter that is smaller than the dripper spacing to be used on the commercial heaps. The stacking practices that cause segregation and stratification on heaps are absent from columns. Intuitively, these physical differences would be expected to be the reasons behind the observed differences between column and heap leaching performance. But how can they be quantified, and what is the magnitude of the differences? Could some of these differences be built into column leaching experiments in order to better simulate commercial-scale heap leaching performance to ease the scale-up calculations from column leaching data? Alternatively, could heap construction practices be improved so that the ideal performance obtained in columns could be emulated on heaps? Data from a few heap leaching cases studies that permit direct comparisons between column and heap leaching performance is analysed, to reveal the extent of the differences in resistance to mass transfer. Discussion is provided on the implications for column and heap leaching practice, and for scale-up design procedures. INTRODUCTION Differences have been known to exist between leaching performance observed in laboratory columns and that of commercial-scale heaps. Both the heap leaching kinetics and finally achievable extent of extraction are generally found to be inferior in heaps compared to that achieved in columns. Heap leaching design engineers extrapolate the anticipated heap leaching performance by multiplying the time-axis of a column-leaching curve by a factor of about 2 and the extraction-axis by a factor of about 0.8, as explained by Jansen and Taylor (2002), Scheffel (2002), John (2011) and Scheffel, Guzmán, and Dreier (2016). The procedure is illustrated in Figure 1 by means of a hypothetical example. The solid line represents the leaching performance observed in a laboratory column, and the dashed line represents the anticipated leaching performance of a heap, extrapolated from the column leaching data using these empirical scale-up factors.

Jan 1, 2019

By Alfred W. Gauger, George A. Burrell

The senior author of this paper, while in Colorado on other official business, made a trip to the Cripple Creek gold-mining district to get more data than are at present available regarding the composition of the gas that issues from the rock into the mines of the district. This was done at the suggestion of George S. Rice, Chief Mining Engineer of the Bureau of Mines. There are -many questions of interest and importance in connection with the ventilation of the mines in the Cripple Creek district, such as the menace to life and mining of a suffocating gas entering the mines from the rock, the danger due to powder smoke (from blasting operations), and danger of continued inhalation of rock dust by the miners. This report confines itself to the first problem, the gas from the rock, and principally to one phase of this question, the composition of the gas and its effects on men and lights. A more thorough study of this and other ventilation problems is planned. That the rock gas is a real menace is shown by the fact that miners (variously estimated from 25 to 50 by different persons interviewed) have been killed by it in the 25 years that mining has been vigorously carried on at Cripple Creek. Many men have had narrow escapes from death, some of them having been incapacitated for days. In addition, much loss of time results because at certain periods of the year or on certain days it is impossible to enter some workings. At a few mines, fans force air into the workings, thus supplementing the natural ventilation and much improving conditions, but the improvement is not entirely adequate at all times. Origin of the Gas Lindgren and Ransome1 think that the gas found in the rocks of the Cripple Creek mining district represents the last exhalations of the ex-

Jan 1, 1917

By E. F. Sturcken, J. W. Croach

A grain orientation distribution function, P(u,F), was developed for use in predicting physical properties in oriented metals. Examples are given of the use of the function to predict thermal expansion coefficients in rolled uranium rods and plate. The P(u,F) function was synthesized from X-ray difpaction intensity measurements, Ii, norrnally used to plot inverse pole figures. The symbols u and F specify the angles that the crystallographic axes of the grain make with the normal to the sample surface and P(u, F) gives the number of grains oriented in each direction, (u,F). P(u,F) is obtained from a least squares fit of the Ii to an orthonormal set of spherical harmonic functions. The P(u, F) function was also used to define a quantity, J, which is a measure of the departure of the orientation distribution from unifomzity (or "randomness"). The J parameter may be used to follow, quantitatively, the amount of preferred orientation induced as a function of mechanical working or heat treatment. An example is given of the application of the J parameter to prefevred orientation studies of hot- and cold-rolled uranium rods and hot-rolled uranium plate. Because P(u,F) is derived from relative intensity measurements by the powder diffraction technique, it is applicable to material with large absorption coefficients and/or grain size and is particularly suitable for characterizing the preferred orientation of large numbers of samples such as fuel elenzents for a nuclear reactor. IN general the physical properties of an oriented metal depend on the direction in which the properties are measured. Hence to predict physical properties the grain orientation must be known as a function of the direction of the specimen. The conventional methods of expressing preferred orientation measurements are the pole figure1 and the inverse pole figure.2-8 Both methods are difficult to use for predicting physical propertiess because they are graphical and because they are stereographic projections and hence are not "area-true." In the present report a quantitative orientation distribution function, P(u,F), is synthesized from pole density measurements normally used to plot inverse pole figures. For inverse pole figure plots the pole densities, pi, are obtained by powder dif-fractometer intensity measurements of their reflections from a flat surface of the sample, normal to the direction of interest. Each pole density, pi, represents a single orientation, i, and is proportional to the volume of material with orientation, i; hence a set of pi gives an approximation for the general orientation for the sample direction measured. The expression8'7 for calculating the pole densities, pi, from the diffraction measurements was previously

Jan 1, 1963

By D. Rendini, R. D. Gutridge

INTRODUCTION Gwinnett County, Georgia, is a part of the rapidly expanding metropolitan Atlanta Georgia area. Located approximately 48 km (30 miles) northeast of Atlanta, Gwinnett County has a current population in excess of 600,000 and is projected to reach a population of 1,200,000 by 2025. As a part of the County’s master plan to supply drinking water for the expanding population and to increase system reliability, the Gwinnett County Public Utilities Department undertook the Shoal Creek Raw Water Intake and Pump Station Project. Figure 1 shows a vicinity map for the project. Prior to construction of the Shoal Creek Raw Water Intake and Pump Station Project the County had a single raw water intake to feed water from Lake Sidney Lanier (Lake Lanier) into a filter plant for processing into potable water. This project together with a newly constructed water filter plant provides Gwinnett County additional capacity and system redundancy to prevent interruptions to the drinking water supply. Lake Lanier is a man made reservoir with over 800 km (500 miles) of shoreline and was constructed by the Army Corps of Engineers in the 1950s for hydro electric power generation, flood control, and navigation benefits for the Chattahoochee River. Over time, Lake Lanier has become an increasingly important source of drinking water for the metropolitan Atlanta area. This paper focuses on the primary underground construction and lake tap components of the project including a 42.7 m (140 ft) deep pump station shaft 24.4 m(80 ft) in finished diameter transitioning to a 6.1 m (20 ft) finished diameter shaft, a3.05 m (10 ft) finished diameter by 19.8 m (65 ft) deep intake shaft constructed in an average of 21.3 m (70 ft) of water, and a 190.5 m (625 ft) by 3.05 m (10 ft) finished diameter modified horseshoe tunnel connecting the two shafts. This raw water intake system, in conjunction with the incorporated pump station with 8 pumps and dual1,829 mm (72 inch) pipelines, provides a system capacity of 1,091,062 m3/day(240 MGD) to two water filter plants and is expandable by the addition of pumps to1,500,210 m3/day (330 MGD). Parsons provided design and construction management services for the project. The $29.6 million contract to construct the project was awarded to W.L. Hailey &Company. Notice to proceed was given August 6, 2001 and substantial completion was achieved on January 20, 2004. Value engineering changes adopted for the project contributed to completing the project at a final cost of $28.8 million.

Jan 1, 2005

IT has been discovered by skilled bell founders, more through experience than from geometrical calculation (although calculation does enter), that a certain relationship of dimensions in both large and small bells makes the tone and the weight almost certainly what is desired. This is in addition to the customary shape which is, according to the historians, perhaps that found by the first discoverers of bells. Among themselves bell founders have made a rule of these measurements and have called it the bell scale. Beginning with the small ones weighing ten pounds, it increases by degrees to a point where, as I have seen, they are able to make them even twenty-five and thirty thousand pounds. This scale is of great enlightenment if one does not have a bell already made for comparison.

Jan 1, 1942

By S. J. Page, J. A. Organiscak

Dust surveys were conducted around small truck-mounted rock drills operating at surface coal mines to assess their airborne respirable dust generation and in-service dust control methods. Of four out of seven drills sampled, respirable dust concentrations measured around the drill deck ranged from 8.68 to 95.15 mg/m with3concentrations ranging from 1.37 to 2.69 mg/m at distances 12.2 to 30.5 m downwind of these drills. The other3drills had noticeably lower respirable dust concentrations measured around the drill deck at or below 1.30 mg/m.3Rotoclone-type dry dust collectors were commonly used with dust being emitted from around the drill deck shroud, collector exhaust, and collector fines dumping. Wind speed and direction was also a factor in the dust concentrations measured on the bench. Dust control modifications were made to three rock drills to reduce their airborne dust emissions. Dust controls tested included water injection into the Rotoclone exhaust, Rotoclone exhaust extension, improved sealing of drilling deck shroud, shrouding the Rotoclone hopper dump process, and wet drilling. These control techniques showed noticeable improvement in dust concentrations measured around the drills. Finally, repositioning the drill operator showed that operator dust exposure can be improved by avoiding the dust cloud around the drill.

Jan 1, 1995

By K. A. Pauly

Compressed air has been and is still very extensively used in connection with mining-operations, but its application in the past has been almost entirely confined to supplying power to underground machinery. Its introduction was due to the difficulty of taking care of the steam which is exhausted underground, rather than to any advantage in efficiency to be gained by its use. The ease with which electric power may be carried to the remotest parts of the mine and the high efficiency of the electric motor have long been appreciated by mine-operators, and electric power is now extensively used underground in the more recent developments, while many of the compressed-air engines in the older workings are being rapidly replaced by electric motors. Recently, however, it has been suggested to use compressed air for driving the large shaft-hoists, the air for the engines being supplied by electrically-driven compressors, and an installation of this character is being erected at Butte, Mont. It is the object of this paper to compare the compressed-air system of hoisting with the various electrical systems, from the stand-points of first-cost and cost of operation. However, before entering into a discussion of the various systems, it will be well to consider briefly the conditions affecting the choice of a system of hoisting in which electricity is the ultimate source of power. The power required by a mine-hoist is extremely intermittent and fluctuates between very wide limits, the all-day average consumption of power not exceeding from 5 to 15 per cent. of the maximum demand during hoisting. The cost of supplying power for such a fluctuating load is necessarily higher than that for supplying an equal amount of

Jan 1, 1912

By J. Koponen, M. van de Vijfeijken, L. Bos

"The availability and reliability of large grinding mills and their Gearless Mill Drives (GMDs) are of paramount importance for the grinding process. Although GMDs have been in service for decades, and are known for their operational efficiency (reliability and robustness with reduced operating cost per ton), compared to conventional drives, in the last decade due to certain reasons some failures led to serious unscheduled shutdowns and significant insurance events.The majority of these notable ""insured"" failures have happened on GMDs installed on relatively large mills, as the financial impact of a failure is proportional to the through-put of the mill. Despite the occurrences of these events, as mining operations are driven by lower ore grades and the ability to continue reducing operating costs per ton, the trend for having larger mills is still very present and there is no reason why this trend should not continue.It is obvious that if not handled correctly, the possibility of large value GMD loss events, coupled with the continuing increase in mill size or required availability and reliability targets, could potentially lead to major conflicts as it becomes difficult for the insurance companies to judge the risk and hence may result in hesitation to insure these grinding circuits. This paper will not only describe the conflicting situation from both an insurer's perspective and from an equipment supplier's perspective, but also how these conflicting challenges can be successfully mastered. It has to be noted that not only the mining companies themselves, but also their insurance companies and the involved equipment suppliers have a common interest: to reach the highest availability and reliability in order to avoid or at least minimize unscheduled shut down times, and most importantly prevent unplanned events that result in extended production stoppages or reductions in through-put of GMD driven mills.From the very beginning onwards, the complete service concept together with emergency plans must be integrated on every level in the design of the grinding circuit. This approach must be implemented continuously and without compromises by all involved parties during all following stages, such as basic design, detail design, manufacturing, quality inspection and testing, packing, transportation, storage, installation, commissioning, operation and maintenance. The concept of formal risk analysis related to mill operations, maintenance and spare parts strategies must be an integral part of mining companies’ decisions related to the selection for installation and continued use of large mills powered by GMDs. The service concept in place for operating mills shall also have a clear focus on very early detection of any abnormalities, so that the risk can be mitigated and unscheduled shutdown times avoided. However, if a major failure occurs, then procedures and tools shall already be available in order to ensure that production impact is minimized."

Jan 1, 2012

By Zhou A, Cadogan J. M

Direct reduction of iron ore (DR) is one of the promising technology emerging in the world's steel industry. Kinetics and Mossbauer studies of DR with hydrogen have been carried out at two temperatures of 600¦C and 800¦C in this investigation. The results show that different controlling steps govern the reduction rate at different temperatures. The mechanism was also found to vary during the reduction. The Mossbauer spectra of the samples reduced in various time intervals were studied to determine the phase changes during reduction.

Jan 1, 1997

Provide reasonably priced, reliable fire protection for AN-FO haulers. Approach An automatic fire sensing and suppression system for AN-FO haulers was developed and on-vehicle tested. How It Works The system works in two ways to protect personnel from dangerous and unpredictable AN-FO fires. First the system senses and suppresses fires on the truck before they spread to the AN-FO in the bunker. This design was chosen because AN-FO truck fires generally start when combustible liquids (such as diesel fuel, hydraulic fluid or lubricating oils) are ignited by hot surfaces mainly on three areas: the engine, the transmission or the power take-off. These fires are quickly sensed by a linear temperature sensor strung throughout these three areas. The system then warns the operator and automatically suppresses the fire by discharging 30 pounds of multipurpose dry chemical extinguishing agent through a network of fixed hoses and nozzles. Second, this system includes six spot thermal sensors mounted inside the bunker on the truck to monitor the AN-FO temperature in case a fire does spread to the bunker area. If the bunker temperature rises to 190° F, a loud siren is sounded to warn nearby per-

Jan 1, 1981

By H. C. George

As the basis for a round table discussion of Petroleum Engineering Education for the February, 1930, meeting of the Petroleum Division, A. I. M. E., the following questions were sent to about 60 of the leading engineers and educators in the petroleum industry: 1. Should there be any changes in the curricula of our courses in petroleum engineering to meet the changing demands of the Industry? If so, what changes?] 2. Should courses in petroleum engineering be offered through university extension? 3. Should the universities offer correspondence courses in petroleum engineering? 4. What should be the character of the graduate work offered in petroleum production engineering? 5. Should summer work in the oil fields, on pipe lines, or in oil refineries be required of undergraduates? If so, how much and of what character? The following men replied to the questions: G. B. Corless, Humble Oil & Refining Co., Houston, Texas. J. R. McWilliams, Skelly Oil Co., Tulsa, Okla. W. W. Scott, Humble Oil & Refining Co., Houston, Texas. H. H. Power, Gypsy Oil Co., Tulsa, Okla. L. G. E. Bignell, Oil K. Gas Journal, Tulsa, Okla. E. L. Estabrook, Pan American Petroleum & Transport Co., New York, N. Y. F. P. Donohue, Pan American Petroleum & Transport Co., New York, N. Y. C. 0. Rison, lndian Territory Illuminating Oil Co., Bartlesville, Okla. L. B. Holland, Phillips Petroleum Co., Bartlesville, Okla. H. J. Kemler, Shell Petroleum Corpn., St. Louis, Mo. C. A. Bonine, Pennsylvania State College, State College, Pa. J. 0. Lewis, Dunn & Lewis, Tulsa, Okla. A. G. Heggem, Tulsa, Okla. J. M. Lovejoy, Petroleum Bond & Share Corpn., New York, N. Y. B. B. Boatright, Colorado School of Mines, Golden, Colo. A. C. Ruble, Union Oil Co. of California, Los Angeles, Calif. J. B. Umpleby, Goldelline Oil Corpn., Oklahoma City, Okla. R. S. Knappen, Gypsy Oil Co., Tulsa, Okla. K. C. Heald, Gulf Companies, Pittsburgh, Pa. K. C. Sclater, Exchange National Bank Bldg., Tulsa, Okla. F. G. Tickell, Stanford University, Stanford University, Calif.

Jan 1, 1930

By Howard L. Hartman

6.1-1. Introduction. Of necessity, the first of the unit operations conducted during the exploitation phase in surface mining is production drilling. It precedes blasting, with which it is associated as the two unit operations employed to break or fragment consolidated material (usually rock) in place. The purpose of production drilling is to provide the cavity for placement of the explosives. So far, no alternative to blasting has been devised for fragmenting very resistant rock in situ, although some forms of excavation (ripping, bucket wheel) are suitable without prior blasting for softer rock, such as weathered shale or mudstone, decomposed sediments, etc. For the vast majority of surface mines, however, drilling and blasting are pre- requisite to excavation and essential to the production cycle. Drilling is also used in surface mining for purposes other than providing blastholes. It finds application during exploration for obtaining samples and during development for drainage, slope stability, foundation testing, etc. Only in the exploitation phase of surface mining, however, are unique or specialized drilling methods and equipment employed; and the discussion in this Section is directed primarily to that application of drilling. Drilling is the most common means of rock penetration, the operation of placing a directed hole in rock. Closely akin to drilling for exploitation purposes is the cutting or freeing of dimension stone in quarrying. This operation, usually termed channeling or sawing, also takes the form of directional penetration of rock; but instead of producing a cylindrical hole, it yields a kerf or cut. The material thus freed from the solid is both a shaped and sized product, an objective of vital importance in the dimension stone industry. In sawing, holes are sometimes drilled to insert tools, but this drilling is a minor part of the sawing operation and employs conventional methods. Cutting, as a unit operation for freeing stone in quarrying, may be considered equivalent in purpose to drilling and blasting in other forms of surface mining.

Jan 1, 1968

By Mark S. Greenleaf, Alec D. Smith, Mary Vittoria-Bertrand, Heather B. Scranton, Jean Louis Z. Locsin

"Rhode Island’s new $163.7 million, 2,265 ft (690 m) long, four-lane Sakonnet River Bridge sits just south of the existing bridge in Portsmouth/Tiverton. The bridge, a critical transportation system link between Massachusetts and Rhode Island, has a steel I-girder main span and concrete New England Bulb Tee approach spans. The foundation work was done between October 2009 and July 2010, and the bridge was completed in February 2014.Foundation design and construction challenges make the project noteworthy. There were thick layers of silty glacial soils with bedrock as deep as 400 ft (122 m) below the waterline, coupled with high foundation capacity demands at the river piers in 50 ft (15 m) of water. The Sakonnet was one of the first major bridge projects in the country to incorporate AASHTO Load and Resistance Factor Design (LRFD) guidelines for foundation design and construction. Because of these and other challenges, the engineers conducted two design-phase load test programs on several foundation elements. These programs were successful and allowed the engineers to adjust the final foundation design prior to the start of construction. During construction, the contractors drove thirty 6 ft (1.8 m) diameter steel pipe piles, each with a novel recessed steel plate insert, to depths of 130 to 200 ft (40 to 61 m) at the three river piers. The insert provided increased resistance of the steel pipe piles and saved about $9 million. Also, 457 14x117 en bearing or friction H-section piles were driven to between 50 and 190 ft (15 to 58 m) at five land piers. All piles were driven relatively close to the existing bridge, which remained in service during construction, due to the project team’s precautionary use of instrumentation and the installation of a jacking system.Area GeologyThe Sakonnet River is up to 60 ft (18 m) deep along the bridge alignment and is underlain by a deep bedrock valley. The bedrock valley is buried by at least 350 ft (107 m) of soil, which includes a complex sequence of interbedded glacial soils (glacial till, glaciolacustrine deposits and glaciofluvial deposits), overlain by geologically recent estuarine deposits. The soils having the greatest impact on the foundation resistance are the glaciolacustrine (fine sandy silt or silt) and glaciofluvial (silty sand with gravel, cobbles, and occasional boulders less than about 2.5 ft [0.8 m] in size). The soil overburden decreases toward the east and west banks of the river, as the bedrock surface rises."

Jan 1, 2015

By Louis W. Cope

Many Americans have seen Greenland while flying over it on their way to or from Europe. Few have visited this largest island in the world. Portions of the 20 percent of the territory that are not ice-covered are highly mineralized. Greenland could become very productive if the present interest in exploration increases. The people and Greenland’s history The population of Greenland is 57,000. Twenty percent are Europeans, mainly of Danish decent, while 80percent are native Greenlandic or mixed Greenlandic-European. The native population is the same as the Inuit of the Canadian Arctic. They speak the same language.

Jan 1, 2004

By E. Ghali, W. Zhang, G. Gabra, N. Sorour, G. Houlachi

The additives polyacrylamide, 1-Butyl-3-methylimidazolium chloride, Tetra-butylammonium bromide, Benzalkonium chloride and chitin are evaluated during zinc electrolysis from synthetic acidic sulphate electrolyte containing Mn2+ ions, in absence and in presence of 0.0055 mg dm-3 of Sb3+ ions. Galvanostatic polarization tests for 2 hours at 50 mA cm-2 and 38oC were carried out to determine the cathodic and anodic potentials, and current efficiency of the deposited zinc. Potentiodynamic polarization and cyclic voltammetry tests have also been employed to study the electrochemical behavior of each additive on the zinc deposit on aluminum electrode. Results showed that, in presence of Sb3+, adding 1 to 3 mg of 1-Butyl-3-methylimidazolium chloride increases the cell voltage by ˜0-7 mV. Current efficiency is increased by ˜4.90-6.40%; power consumption is reduced by ˜147-173 kWh t-1 by adding 1-3 mg, respectively. However, in absence of Sb3+, cell voltage is decreased by ˜7-28 mV, current efficiency is increased by ˜0.70-1.50%; power consumption is reduced by ˜41-47 kWh t-1 by adding 1-3 mg. The effect of the other additives on cell voltage, current efficiency, lead content and morphology of zinc deposit has also been examined. Surface morphology and crystallographic orientation of the deposit was studied using scanning electron microscopic (SEM) and X-ray diffraction (XRD), respectively. The content of lead in the deposit has also been measured using inductively coupled plasma spectroscopy (ICP).

Jan 1, 2015

By J. D. Cooner

Since my working life of 32 yr has been spent in and about the anthracite mines of the Hudson Coal Co., and the previous 4 yr in a college school of mines, I can write best about the safety program of a coal mining company. However, most of the suggestions, statements and practices mentioned herein are applicable to the members of a safety organization and program of almost any industry. It is realized that industrial officials actually interested in real safety work are fully acquainted with the requirements of a practical safety program. Therefore, for such persons there may be nothing new in this paper. The Hudson Coal Co. of Scranton, Pa., employs 7000 men and produces 5,000,000 tons of anthracite annually at nine collieries scattered for a distance of 40 miles throughout the Lackawanna and Wyoming valleys of northeastern Pennsylvania. For the past 17 yr of the above mentioned 32, I have been engaged in safety work as a safety inspector, assistant mine superintendent, and at present the safety engineer. I have also had the privilege of visiting coal and metal mines in other parts of the United States and Canada. We Americans are the most careless people in the world. If any one doubts this statement why are 100,000 of our people killed accidentally annually? Or why during the almost four years we were engaged in World War II were more of our people killed accidentally at home than were killed in our army, navy, marine corps, coast guard, and other services during the same period? We are careless everywhere— in our homes, on the highway, at work and at play. The purpose of this paper is to outline the requisites of a safety department and its program to stop the accidents occurring to employees at work in mines or industrial plants. The first requisite for a safety program is that the management must be convinced of the need and value of a real safety program. By "management" is meant each department head from the president down. Otherwise a good safety department with a good safety program will not succeed because it will not have the proper personnel and equipment to work with, its rules and regulations will not be enforced, and the members of the safety department will be belittled in the eyes of most of the workmen and supervisors. Next, a safety engineer and his inspectors should have worked in the production end of the mines as workmen and also in an official capacity. They are then in a position to have practical and first hand knowledge of the accident hazards of the industry, how to prevent them, and in general the problems of both the workmen and officials. Some men are appointed as safety inspectors when they are physically unable to carry on as mine officials. Such men may know the safety end of the industry and even be safety-conscious, but if they are physically unable to be mine officials they are also physically unable to be safety inspectors, as a safety inspector in our mines must walk from 2 to 4 miles on each daily inspection and visit each working

Jan 1, 1949

By P. Nicholls

THOUGH the burning of fuels extends far back into antiquity, and though fuel beds are the most common and widely distributed example of chemical actions and engineering practice, there has been little attempt to group fuel beds by types or to define the principles associated with them. This paper does not profess to cover completely the subject of fuel beds. It suggests some of the over-all principles of the two more com-mon types. No new investigational data are included, but the deduc-tions are largely based on a recent publication of the U.S. Bureau of Mines1. DEFINITION OF TYPES There are three primary types of fuel beds: (1) Underfeed, in which the fuel and the air move in the same direction; (2) overfeed, in which the fuel and the air move in opposite directions; (3) crossfeed, in .which the fuel and the air move at right angles to each other. The principle that fixes the type is the relation between directions of the flow of fuel and of air. Fig. 1 shows the three types diagrammatically. All other types are compounded of these three in a simple or more or less complex manner. It does not follow that these three type designations are limited to the methods used in representing them in Fig. 1; they may be turned in any direction, and as long as the relative directions of the fuel and air are the same the type is not changed. For example, A as shown resembles a pot-type stoker, but the air and fuel can move downward as in the so-called smokeless heating boiler furnace. Also, C can be placed hori-zontal, as in chain-grate stokers. For this reason, the terms used to designate the three types are not all that could be desired; more logical ones could be coined, but those used probably are satisfactory until the discussion of fuel-bed types becomes more common.

Jan 1, 1935

By Charles Seastone

Location THE hydro-electric plant of the Peninsular Power Co., is located at what is commonly known as Lower Twin Falls on the Menominee River. This location is about 33 miles north of the city of Iron Mountain, Mich. The principal points of delivery of electric energy from this plant are in the mining regions adjacent to Florence, Wis., and Iron River, Mich., and in the cities of Iron River and Iron Mountain. The hydro-electric plant at Twin Falls and the substation of the Iron Mountain Electric Light & Power Co. are connected by a 6,600-volt transmission line carried on steel towers and steel poles, the latter being used within the city limits. The plant at Twin Falls and the substation at Iron River, about 36 miles distant, are connected by a 66,000-volt, duplicate, three-phase transmission line, supported on steel towers. At Iron River, are located a 1,500-kw. auxiliary steam plant, and the substation, from which the current is distributed to the mines in this vicinity. A description of the auxiliary plant, main and customers' substations, and of the main and secondary transmission lines, follows later in this paper.

Jan 2, 1915

By R. S. Archer

BERYLLIUM has certain properties such as low density, high hardness, good corrosion resistance, low thermal expansion and fairly good electrical conductivity, which would indicate that it, is worthy of consideration as an ingredient of light alloys. It was not until recently, however, that beryllium could be produced with sufficient ease to encourage research along this line. The production of beryllium by electrolysis from a fluoride bath has now developed to the stage where it could be used commercially if there were sufficient demand for the element. Claims made in certain newspapers and technical articles in regard to the strength and corrosion resistance of the aluminum-beryllium alloys are not justified by experimental results. Moreover, beryllium is an expensive metal ($200 a pound at the time this work was done) and, on account of the nature of its ore and the consequent difficulty of its extraction, it will in all probability continue to be a relatively expensive metal, although the cost would undoubtedly be a great deal less than $200 a pound if the metal were produced on a large scale. It seemed, therefore, that low-beryllium alloys offered the greater commercial possibilities except for very special purposes. It was partly for this reason that in the present work emphasis has been placed on beryllium alloys of low beryllium content.

Jan 1, 1928