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By Gordon Kidd

Inflation and burgeoning costs are two among many factors which have generated a new surge of interest in "fringe benefits" (sometimes referred to as "supplementary remuneration" or "supplementary compensation"). Other specialized forms of compensation ("perks", in the vernacular) such as company cars, windowed offices, etc., which also are the subjects of current study, are outside the scope of this paper. For businesses, interest in fringe benefits is based on concern for employees? welfare, compliance with government requirements, and an increasingly burdensome impact on bottom lines. In 1980, according to Fred D. Lindsey in the October 1980 issue of Nation's Business, employee benefits will cost American employers an estimated $420 billion. To paraphrase Winston Churchill, "some fringes!" Indeed, few if any administrators consider employee benefits as fringes. Employee benefits impact other major areas of a company's operations as well. As listed by Beadle (1980), these areas include employee relations, collective bargaining, short-term costs, long-range funding, manpower planning, compliance with legislation, taxation for the company and for the employee, corporate image in the community, competitiveness for staff, communications, administration, claims cost containment, etc., etc.

Jan 1, 1980

By Vas Choudhry

The eighties are likely to witness the first commercial-size coal-to-gasoline plant(s) in the U.S., although uncertainty regarding crude prices and cautious involvement of the Federal Government in the synfuels development are evident. The formation of The U.S. Synthetic Fuels Corporation with passage of the Energy Security Act is projected to pave the way for some of the projects on a moderate scale. The corporate objectives (1) are to provide funds for supporting a number of feasibility studies and loan guarantees for the construction of at least some commercial-size plants and the possibility of product price supports or purchase commitments. There are a number of coal conversion processes (2) currently under evaluation for producing either gaseous or liquid plus gaseous fuels, the other processes such as SRC I are for producing desulfurized deashed clean solid fuel for commercial use.

Jan 1, 1982

By Keiji Toyabe

Several purifying techniques have been developed for controlling the impurity levels in the copper electrolyte at Niihama Copper Refinery. These have been carried out as follows; i ) the study of the reaction in liberation made it possible to raise the current efficiency for arsenic removal by more than 50% and to decrease generation of arsine sharply. By applying this method, a good performance was attained at commercial operation. li) the antimony in the electrolyte can be successfully removed by contacting it with activated carbon. This procedure is applicable particularly when there is a large amount of antimony in the copper anode. lli) for the nickel sulphate recovery from the electrolyte, an electric evaporating system was developed. The characteristics of this process are, capability of continuous operation with less manpower, the high recovery ratio of nickel sulphate (more than 85% as nickel) and no black acid formation in the treated solution.

Jan 1, 1987

By F. T. Paleari

Radial gas holdup profiles have been measured in a 50x400 cm flotation column using a multi-cell conductivity probe. Three different bubble generation systems were examined: up to eight vertical filter cloth spargers, three horizontal filter cloth spargers, and three (horizontal) Cominco-type spargers. The variables tested were: number of spargers, symmetry of their arrangement, and height above spargers. Batch water with up to 20ppm frother concentration was used. The general observation is that the profiles tend to be uniform (i.e. flat) with some exhibiting a slight wavy shape. The vertical sparger arrangement proved the most difficult to achieve profile symmetry. The horizontal spargers gave uniform profiles at right angle to their length but a decreasing gas holdup along their length; the Cominco-type spargers gave slightly less scatter in the data. Switching off selected spargers (to simulate malfunction) did not produce strong asymmetry in the profiles.

Jan 1, 1993

By Michael J. Friedel

As part of an investigation aimed at mitigating the hazards caused by abandoned mine openings, the Bureau of Mines conducted a series of electromagnetic surveys in the Galena, KS, area of the Tri-State mining district. The application of monostatic ground-penetrating radar (OPR) and inductive electromagnetic methods for detecting and delineating hazardous mine openings and attendant features was demonstrated to be feasible for shallow mine workings (i.e., less than 35 ft) occurring below flat-lying areas. Accurate determinations of depth to a mine roof appeared to be limited to roughly 20 ft using the GPR method. Features such as mine voids, fractures, and zones of subsidence were located beneath the Mainstreet (State Highway 26) site using the GPR system. Both the GPR and inductive electromagnetic techniques satisfactorily located mine openings and pillars at the Hell's Half Acre site. Geophysical interpretations were supported by exploratory drilling and mine maps.

Jan 1, 1990

By Zhong Zhang, Xijia Wu, Prakash C. Patnaik

"The integrated vehicle health management (IVHM) aims to provide life cycle management decisions for military platforms and their propulsion systems with reduced life cycle cost and increased operational readiness and safety. Among all the issues of IVHM, understanding the physics of failure and predicting lifetimes of the critical components are at the core: the decision makers have to know when and how components may fail in order to plan ahead. The difficulties to tackle failure problems lie in determining the material response to cyclic and dwell loading in a hot and/or corrosive environment, which all combined to induce multiple deformation and damage mechanisms, resulting in mix-mode failures. Decisions on component replacement (material substitution) and mission planning must be based on quantitative knowledge of the failure physics to mitigating the risk. This paper addresses the critical failure issues including creep, low cycle fatigue (LCF), thermomechanical fatigue (TMF); and presents a mechanism-based approach to life prediction. The mechanism-based approach, by its physics, is widely applicable over the entire operational spectrum of both structures and engines, and therefore is suitable for IVHM purposes."

Jan 1, 2015

By M. D. Schlesinger

Experimental data for coal hydrogenation are presented to show that when a vehicle oil produced from coal is present, coal is hydrogenated to the same high conversion whether molybdenum catalyst is impregnated on the coal or intimately mixed with the slurry. Differences in product distribution could be related to the severity of operating conditions. No minimum mixing time was established, but 2 hours was sufficient. Longer periods of mixing, to 14.75 hours, had no effect on the results. The hydrogenation conditions were in the pressure range of 8,500 to 10,000 p,s,i. at 400° to 500° C. Most of the experiments were made in duplicate. The results were obtained with molybdenum concentrations of 0.01, 0.1, and 1 percent. Al the mentioned pressure range and a time at temperature of 15 to 60 minutes, coal conversions higher than 98 percent were obtained.

Jan 1, 1962

By E. H. Burdick

THE difficulties inherent in table concentration operations as applied to gold, silver, lead and zinc ores, are accentuated in the scheelite mill, which has a flowsheet that is similar in general principles. The narrow "spread" in the specific gravity between scheelite and the usual gangue in which it occurs often makes its clean separation extremely difficult and in some cases impracticable. The problem is further complicated by the extreme friability of the mineral and its inordinate tendency to "slime," particularly where fine grinding is necessary and wet grinding methods are employed. The physical aspect of the occurrence of scheelite in the ores, the kind and character of the rock in which the mineral is present, its hardness, friability and the specific gravity of its constituents, as well as like characteristics of the associated minerals-pyrite, pyrrhotite, sphalerite, and others, all have a bearing on the successful milling of crude ores and the production of a concentrate that is marketable with minimum price penalty or none at all. Most tungsten deposits are considered low grade when the limiting factor of low percentage recovery by gravity methods is borne in mind. The great majority of deposits developed or in process of development carry from 0.4 to 1.0 per cent tungstic oxide. Ore carrying I per cent is considered good grade; 0.7 to 0.8 per cent, fair, and below that figure, low grade. Steady mill feed averaging upward of 1.0 per cent W03 is exceptional. Inasmuch as buying specifications demand a 60 per cent W03 content, the mineral content of the ores as mined must be concentrated to at least that degree. A few companies have constructed chemical plants for the treatment of their complex concentrates and low-grade flotation product, but the smaller operator must rely on table concentration, borrowing the tools and to a large extent the methods of his predecessors in the gold, silver, lead and zinc mills. Whether these are the best tools and methods that can be devised is an open question. Except in rare instances, table concentration, however carefully conducted, does not yield a satisfactory final recovery of the mineral content in headings as indicated by chemical determinations of tungstic oxide content. A saving of 60 to 65 per cent is considered fair, and an average 80 per cent recovery, exceptional. Each scheelite ore body is a separate problem. Details of handling that give best results in one case may not be successfully operative at a property on the same contact zone and but a short distance removed. Supplementary treatment of tailings by flotation may be successful in producing a low-grade concentrate of around 15 per cent WO3, which is adapted to further treatment chemically at a given property and entirely unsuccessful at another. This problem constitutes another of the unanswered questions. The following paragraphs relate solely to the beneficiation of scheelite ores by table concentration and supplementary methods.

Jan 1, 1942

By Nikhil Dhawan, SHAILA MIR

The emerging problem of electronic waste has promoted the interest in exploring metal recovery from secondary sources under the umbrella of urban mining. This study presents the physical and chemical characterization of various components present in end-of-life laptops to help ascertain the sites of metallic values and develop sustainable and environment-friendly recycling. The recycling potential of a laptop is evaluated by sequential disassembly, separation, and characterization of components such as body (49.8 wt.%), printed circuit board (9.7 wt.%), hard disk drive (4.9 wt.%), and battery (12.4 wt.%). The printed circuit boards comprise metallic values, majorly copper (25 wt.%), tin (5.8 wt.%), and lead (3.1 wt.%). The precious metals (Au, Ag) with an economic advantage are abundantly present in electronic components such as integrated circuits, capacitors, resistors, and processors. Critical elements such as lithium, cobalt, and rare earth elements are detected in the discarded laptops' batteries and hard disk drives. The recycling potential representing the amount of material that can be recycled in various components, depending on the type, concentration, and purity, is determined in the range of 36–100%. On average, a unit laptop contains~ 386 g of Cu (14.45 wt. %), 49.73 g Co (1.86 wt. %), ~346 mg Ag, ~141.2 mg Au, ~650 mg of rare earth elements (Nd, Dy). This study presents a database for investigating integrated and economical recycling techniques from different components of a laptop, and an overall process flow is also proposed.

Jul 24, 2021

By L. C. Raymond

Good afternoon. I have entitled my talk "Investment for Progress," implying thereby a spark of friendly competition by private enterprise with such government-inspired foreign aid and investment programs as the Alliance for Progress. While the subject of foreign investment is hardly a new one, the perpetual flux of the political and economic surface of this earth we inhabit makes it forever timely and forever interesting. Especially do tremendous opportunities for international investment constantly present themselves to the mineral industry, and just as often must the industry approach these opportunities with a great deal of investigation and caution. This is not to say that the mineral industry--no less than any other industry--should be unenthusiastic about the foreign scene, but like everyone who proposes to put his money where his hope is, it should consider all the factors and weigh the possible disappointments as well as the rewards.

Jan 1, 1964

By A. Andreas Hejja

Flow of slag and settling of matte in slag resistance electric furnaces are discussed in conjunction with furnace geometries, stirring action of the electrodes, buoyancy and electromagnetic effects. The rectangular electric furnace was regarded as a channel reactor and the mode of slag flow as a channel flow. The flow is affected both by buoyancy and electromagnetic forces, however the effect of electromagnetic forces is minimal. The flow velocity is made up of two components; (i) that developed by the action of the electrodes, and (ii) the bulk flow velocity determined by the smelting rate and the volume of the reactor. Slag samples were taken from various depths of the molten bath and were analyzed microscopically to determine the size and distribution of matte particles, The action of the electrodes was described by a simple mathematical formula indicating a balanced settling rate in the area of electrode action.

Jan 1, 1996

By L Zhang

The Chinese coal industry is the largest coal producer in the world. The total production in I995 was 1.28 bnt. On the way towards introducing a market economic system, this mature industry is facing major challenges. The main problems are a large surplus of manpower, shortage of current assets and capital, low productivity, high casualties and a huge deficit. This paper discusses the present situation and the future developments in the Chinese coal industry. The current policy can be stated as ‘rapidly developing the state collieries and improving the village and private mines; integrated development to achieve an economic operating scale and encouraging a diversified economy; rapidly exploiting and developing in the North west and South west; promoting productivity and efficiency; welcoming multi-sources and types of investment; setting up coal exchange markets; and the careful control of resources and the environment'.

Jan 11, 1996

By R. Pazhianur

Cathodic Protection using impressed current was employed to reduce the wear of the mill wall during ball mill grinding. Wear rates were determined from weight-loss measurements made on four, I-inch diameter, mild steel coupons installed flush with the interior surface of the mill wall. Grinding tests were conducted on quartz, pyrite and quartz-pyrite mixtures at pH values of 4.6, 7.1 and 9.2. Cathodic protection was shown to reduce mill wear by 40-60010. An examination of the coupon surfaces using scanning electron microscopy showed that cathodic protection greatly reduced pitting corrosion. The presence of a sulfide mineral, such as pyrite, was found to increase the wear rate significantly, possibly due to galvanic interactions. It is also found that the wear rate is significantly higher than the sum of abrasive wear and the corrosive wear, due to a synergistic effect.

Jan 1, 1996

By J. S. Redpath

There appears to a definite trend toward the hoisting of greater tonnages from greater depths. There is every indication that this trend will continue and we feel that improvements in the design, fabrication and installation of mine guides will be of significant importance in the future. The present state of the art in mine-shaft guide systems is reviewed and the parameters required for improvement are derived in this paper. Finally, a proposal is made for a new steel guide system which meets the parameters and is economical to fabricate and install.

Jan 1, 1977

By AIME AIME

MINERAL production of the United States is valued at over five billion dollars a year at present and the industry employs close to a million workmen, yet such maps as are available that might indicate the geographical distribution of this industry show only the location of coal and oil fields and of other mineral deposits. No recent map is available that shows this distribution in a quantitative way. The purpose of the maps and graphs here presented is twofold: (1) to give the mining engineer a clear conception of the relative value and the pattern of distribution of minerals in the United States; (2) to test the so-called block-pile (or grouped pillar) system of statistical mapping, which makes this presentation possible. (I discussed this method of mapping in an article which appeared in Economic Geology in 1939, Vol. 15, p. 185-188.)

Jan 1, 1941

By M. D. Hassialis, Arthur F. Taggart

WARK1 observed some years ago that collector-coating reactions with xanthates and with fatty acids clearly follow paths parallel to those prescribed by the familiar mass-action law for reactions in dilute solutions. He proposed, therefore, the logical hypothesis that they are governed by the solubility=product principle. However, he went astray in the application of his proposal to collector coating by overlooking the fact that coating involves a heterogeneous reaction. A mistaken concept of the meaning of the word adsorption also entered. Wark thought that the concentration of metallic ion that must be used in setting up the solubility-product equation for the coating reaction was that which could be obtained by solution of the mineral. Since this is very low for sulphide ores, and since the amount of the collector ion necessary for coating produces an extremely low concentration, the resulting ion-concentration product, under conditions when coating occurs, is much lower than that which would indicate a saturated solution of the collector-coating compound. Hence he was forced to the position that the solubility product governing the coating is much smaller than the standard solubility product. To justify this position it was necessary to postulate a coating mechanism that did not obey the ordinary laws of chemical reaction. This Wark did by adopting the concept that adsorption is a property of matter, rather than merely a more or less ephemeral local concentration thereof. Thus he says (p. 142 of ref. I): "Adsorption is not a purely physical property of the solid surface, for the specific nature of the adsorbed molecule or ion is important." The result was that he destroyed the great potential utility of his postulate by tying it to this erroneous concept in the words (pp. 142, 143): "It will be obvious that the adsorption solubility product is less than the normal solubility product." The writers have found quantitatively in the case of galena and potassium ethyl xanthate, and semiquantitatively in the case of covellite and the same collector, that the coating reaction does follow the mass-action law to the extent that coating occurs when the ordinary solubility product of the coating compound is exceeded, and that coating does not take place under the reverse conditions. In the course of the investigation leading to the establishment of this fact it was necessary to work with xanthate concentrations so low (down to 0.0004 mg. per liter), that very long conditioning times, and bubble-contact times of as much as 16 hr. were necessary sometimes to follow the reactions. The results have led to some illuminating conclusions as to necessary collector concentrations in normal flotation operations, and the action of the frothing agent in connection therewith. The experimental work comprised. accurate determination of the standard solubility product of lead ethyl xanthate, development of a much less laborious

Jan 1, 1946

By Jefferson Caponero

The tire is an expressive component of Municipal Solid Waste, manly when its occupied volume is considered. Its treatment by pyrolysis stands for a list of advantages, such as: landfill releasing and a production of a high quality fuel. The exploitation of new natural resources is becoming more difficult each day, basically due to the environmental damages caused by this type of activity. This work presents a study on the thermal behaviour of Brazilian tires using thermogravimetric analysis and differential thermal analysis, in order to optimise the pyrolysis process of tires. Samples of I to 2 mm were investigated at atmospheres of nitrogen, argon, oxygen and mixtures of these gases at temperatures up to 1273K, under heating rates between 1 to 50 Klmin . The results showed that the behaviour of each sample is related to both the atmosphere composition and the heating rate.

Jan 1, 2001

By John S. Berber

Acids, neutral oils, and pitch were produced by distillation of low-temperature lignite tar and processed to upgrade them into more valuable products: The acids were separated from the distillate and catalytically dealkylated to produce phenol, cresol, and xylenol. Aromatic and naphthene fractions of the neutral oil were converted into phthalic and maleic anhydrides by catalytic hydrodealkylation and vapor- phase oxidation. Paraffins and n-olefins from the neutral oil were processed into alkybenzene sulfonate, a biodegradable substance. Aromatic materials from the neutral oil were also extracted with organic compounds and the extract hydrogenated under pressure to produce jet fuel. The pitch was processed by various means to change its characteristics and make it suitable for similar applications as high- temperature tar pitch, including preparation of carbon black and metallurgical electrodes. In most cases, products obtained from the low-temperature tar were examined for physical and chemical characteristics and for potential commercial utility. Information obtained from this research would be helpful if a new coal- chemical industry based on tar utilization were established.

Jan 1, 1973

By Rose L. Ballard

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are tables that show the principal nonfuel mineral commodities exported from and imported into the United States, and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1982

By Anton Sroka

The German hard coal production predominantly derives from underground multiseam mining activities. Beside common surface damages, ?inner mine damages? on underground infrastructures (i.e. main roads, cross cuts and shafts) due to mining excavations occur to an increasing extent. As these "inner mine damages" dramatically increased because of the development towards high performance longwall mining technologies, this matter raised to be a severe problem concerning mining economics. To protect durable and long lasting underground infrastructures, precautionary measures such as suitable mine layouts, adapted planning of mining operations and moderate face advances have to be considered. Some examples of "inner mine damages" recorded by means of mine surveying methods are given in this paper. An empirical-mathematical model based on the principles of mining subsidence engineering methods will be introduced. This model allows to minimize ?inner mine damages? and helps to support and optimize mining processes.

Jan 1, 1999