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By Robert J. Neubauer

I was asked here today to discuss the first long-term freight rate contract ever signed by a U.S. railroad and shipper. That was ICG's contract with the hoosier energy company to haul coal from southern Illinois to an Indiana power plant. I?ll also talk about why you can expect to see more such contracts in the future But first, let me tell you a little bit about the Illinois central gulf railroad and why coal contracts are so important to us. ICG is a principal mid-American freight carrier. We are one of the ten largest railroads in the united states and one of the ten largest coal-hauling railroads. ICG links the industrial great lakes region with the warm weather ports of the gulf coast. Some of the major points on our route map are Chicago; Indianapolis; Omaha; Kansas City; Memphis; St. Louis; and, of course, baton rouge and new Orleans.

Jan 1, 1981

By J. W. Furlan

Due to the time consuming nature of froth testing in a laboratory environment, it is required, due to practical limitations, to develop a method of applying a single set of performance test data (Visintainer & Whitlock, 2012) obtained for a single froth pump at a given speed, to a range of froth pump speeds and sizes, % air contents, and liquid viscosities. Head, efficiency, and flow all vary as functions of both liquid viscosity and air content. As such, it is necessary to develop a technique which can be used to interpolate from existing test data in order to predict froth pump performance for pumps of various sizes running at variable speeds. Details of the technique developed in order to achieve this goal as well as the insights gained from analysis of the resulting regressions are discussed. Additionally, comparisons are made between the performance predictions of this test-derived method and those of the Hydraulic Institute Standard for the effects of liquid viscosity on centrifugal pump performance (ANSI/HI 9.6.7-2010).

Feb 27, 2013

By A.S. Richardson

AIR conditioning, or air cooling, for the improvement of ventilation in the Butte mines has come into increasing use during the past 10 years. In part, the methods practiced have been described in previous publications of the Institute, but some improvements on earlier methods have been made and a number of new features have been developed. This paper is presented as a record of progress made, and for the sake of completeness describes all general features of the work. The need for air conditioning in the ventilation of mines in the district arises from the fact that the temperature of the ground and mine water has shown a very great increase with increase in mining depth, and has now reached a maximum of slightly over 130°F. The most difficult part of the ventilation problem is the maintenance of temperature and humidity of a satisfactory standard in the working places, especially on the lower levels. Although ordinary ventilation is adequate to maintain good conditions in most of the working places it is subject to a number of limitations at great depth. Most important among these limitations is that with increase in depth the air becomes heated before it reaches the working places, both by compression from increase in atmospheric Pressure and by heat transferred to it from rock at high temPerature, so that its capacity for lowering temperatures is greatly reduced before it reaches the operating zone. Increasing depth of mining also increases the distance traveled by the air in its passage through the mine, and this causes a corresponding increase in resistance to air flow, so that there is greater difficulty in maintaining even the same volume in circulation. Thus, in the face of a demand that the ventilating system have a very much greater capacity to remove heat from the mine, the tendency is for that capacity to diminish. The only evident alternatives were (I) the opening of additional air shafts to increase the volume of air in circulation, (2) an extension of the existing system that would be subject to the same limitations, or (3) the adoption of an entirely different method such as air cooling. Fortunately for an economic solution of the problem, the mean annual temperature of the surface atmosphere at Butte is about 40°F., with very low relative humidity in summer, so that there is unlimited natural cooling power at a temperature range adaptable to air-conditioning methods. Methods Two similar methods of air conditioning are used, as necessitated by service requirements and dependent upon the equipment available. In one, which is the more important and has the greater cooling capacity, water is circulated in a closed circuit, and, alternately, first absorbs heat from warm mine air and then dissipates it in the surface atmosphere by cooling at a cooling tower. The second

Jan 1, 1943

By Wenbin Zhang, George W. Poling

"Prior or simultaneous addition of ammonium sulphate can, not only enhance the activating effect of hydrosulphide ions on xanthate flotation of malachite but it can also eliminate possible detrimental or depressing effects of excess residual hydrosulphide . Use of relatively inexpensive ammonium sulphate appears to reduce the consumption of the much more expensive sulphidizing agent for optimal flotation recovery INTRODUCTIONOxidized copper minerals float poorly with conventional thiol-type collectors. This is believed to be due to the nonadherent character of the collector coating, which is readily re- moved by particle abrasion. Rosas and Polingr reported emulsion flotation seemed capable of resisting abrasion during the flotation of non-sulphide copper ores. It appears that the most common flotation technique for oxidized copper minerals comprises sulphidization with Na .S and subsequent treatment by sulphydryl collector. The principles of this method are available . Malghan recently reviewed the studies on the role of sodium sulphide in the flotation of oxidized copper, lead and zinc minerals.It is well known that in the sulphidized flotation of malachite, the activation process depends strongly on the concentration of the sulphidizing agent, i.e., insufficient sulphide gives poor recoveries because of inadequate sulphidization; excessive sulphide also causes poor recoveries due to the depressive effect of the residual hydro-sulphide ions in solution. A major difficulty in sulphidization, especially with a varying feed nature, is to establish and maintain the optimum sulphide concentration in solution. In plant practice, vigorous control of sodium sulphide is required and stepwise addition of the reagent is recommended to improve the efficiency of the process. Soto and Laskowskim have found that malachite, depressed by an excess of sulphide ions, can restore its floatability if air or oxygen is introduced to the pulp. They attributed this to the oxidation of the HS - ions on the surface of the mineral. Jones and Woodcockuvi showed that a sulphide ion selective electrode could be used to optimize the conditions (e.g . amount of hydrosulphide, sulphidization time, flotation time) more readily and precisely than existing methods in the flotation of oxidized copper ores."

Jan 1, 1989

By Shun-ichi Satoh

The electric arc welding of cast iron has been studied by Braune Lamberton, Schimpke, Kenyon, Gale Manufacturing Co., Wedemeyer Candy, Neese, Miller, Carter, American Welding Society, Namack Lebrun, Achenbach, Jansson, Xochendorffer and others.' The write of this paper has been able to obtain a series of cast irons, from gray tc white, without using cast-iron electrodes but by coating on wrought-iron bars mixtures of carborundum (Sic) and graphite (C). In this work, he found the curious phenomenon of barium carbonate.

Jan 1, 1929

By C. M. Sellars, F. Maak

Electvomotie -force measurements hazle been made on ten Au-Ni alloys at temperatures 7754 825O, 900O, and 935°C using galvanic cells with solid electrolyte. Partial and ivtegral thermodynamic functions are derived from the determined activities. which show la9,ge positive deviations jvom Raoult's law. The enthalpies of mixing- are in close accord with calorinletric data and are of comparable accuracy. The results are used to determine the miscibility gap and the spinoidal curL1e, and are qlalitaticely interpreted in terms of the large size difference and electvonic interactions between gold and nickel. Tabulated nalues of the actielities and partial and inteqal free energies, entropies , and enthalpies of mixing are given in the appendix. The Au-Ni binary alloys are of particular interest thermodynamically as despite the large size difference between gold and nickel atoms they have a simple phase diagram.' This shows complete solid solubility above a miscibility gap with a maximum at about 71 at. pct Ni and 810°C. Activity measurements (over a range of temperature) have been made previously on this system using an electrolytic-cell method with a liquid chloride eletrolyte. The accuracy of this data has, however, been queried3'4 as it leads to values for the enthalpy of mixing which are too high when compared with calorimetric measurements.46 Also, the entropy of mixing is too high when compared with the values derived from specific-heat measrements. It was therefore considered worthwhile redetermining the activity data using a galvanic cell with a solid electrolyte (0.85 ZrO, 0.15 CaO). This method is based on a technique introduced by Kiukkola and aner'' and has been used to determine the thermodynamic data for Cu-Ni alloys.' THE ELECTROLYTIC CELL The cell used to determine the activity of nickel in Au-Ni alloys was: The cell reaction, which is discussed for a similar cell by Rapp and Maak, gives a direct measurement of the activity of nickel in the alloys as where aNi(alloy) is the activity of nickel in the alloy, 3 is Faraday's constant, E is the measured electromotive force, R is the gas constant, and T is absolute temperature. For the valid application of this type of cell the arrangement must be ther modynamic ally stable, which means that: 1) The free energies of formation of the oxides fulfill the relation 2) The vapor pressures or dissociation pressures of each component must be so small that during the time of the experiment the amount of any material transported by the gas is negligible. 3) Side reactions which change the alloy composition must be negligible. These reactions are possible both with the surrounding gas atmosphere and with neighboring solid material. The first two conditions are fulfilled by the above cell.' The third condition is approached by care in the experimental technique. The factors which control the attainment of equilibrium in this type of cell have been considered by Rapp and aak, who conclude that metallic diffusion in the alloy is the rate-control ling step. A lower temperature limit for the practical application of this cell is therefore set by the condition that equilibrium must be attained in reasonable times. EXPERIMENTAL MATERIALS AND TECHNIQUE The starting materials were mint gold (99.99 pct Au) and Mond nickel (99.9 pct Ni). Alloys, nominally 5 at. pct Ni and then each 10 at. pct across the system, were produced by vacuum-levitation melting compacts of mixed drillings of the pure metals. The nickel used for the reference tablets in the cells was melted in a similar manner. The alloy ingots, cast in boron nitride molds, were cold-forged and

Jan 1, 1967

By Nobuyuki Okamoto

The 21-year long-term Japan-SOPAC Cooperative Deep-sea Mineral Resources Study Programme was completed in March 2006. The Programme, which commenced in 1985, has seen numerous marine research surveys being conducted within the Exclusive Economic Zones (EEZs) of 12 SOPAC member countries (Figure 1). The various research and government institutions that have been closely involved in this longstanding Programme include: the Japan International Cooperation Agency (JICA); Japan Oil, Gas and Metals National Corporation (JOGMEC) (formerly, the Metal Mining Agency of Japan, MMAJ) and relevant ministries of the participating Pacific Island governments.

Sep 24, 2006

By Paul S. Lewis

The Bureau of Mines hydrogenated coals of different rank that had been irradiated with either x-rays or gamma rays. Lignite, high-volatile A and C bituminous, and low-volatile bituminous coals were exposed to l billion roent¬gens of gamma-ray radiation; specimens of high-volatile A and C bituminous coals from other sources received 6 million roentgens of X-ray radiation. Irradiated and unirradiated control specimens of those coals were hydrogenated in autoclave experiments at (6,000-p.s.i. final pressure and 400° C. with retention times of 15, 30, or 60 minutes depending on the coal rank and catalytic treatment. Comparison of results from irradiated specimens with those from the control experiments showed that the radiation had no beneficial effect on the coal. High-volatile C bituminous coal may have been affected by radiation more than the other coals. One billion roentgens appeared to reduce the amount of coal converted to liquids and gases by about 10 pct., and 6 million roentgens reduced it by about 6 pct. then catalyzed with tin. In all other cases, the conversion of irradiated coal was either reduced by as much as 4 pct. or was essentially the sank as that obtained with unirradiated coal. Irradiation during hydrogenation nay be effective for increasing the reactivity of coal and should be investigated; further work with coals irradiated prier to hydrogenation is not recommended.

Jan 1, 1962

By T. B. Armstrong

"The energy situation is extremely fragile and there is a critical need for energy conservation in the short term and development of new technology in the long term. To keep tabs on energy flow, separate electrical metering is being installed in major industries: The first step reduces demand through peak load control; the second reduces the waste of energy by monitoring energy used per unit of production. IntroductionThe current energy situation is best described as being extremely fragile. The supply of hydrocarbons is being exhausted, while energy needs remain the same in the industrialized nations and are increasing in the Third World.The petroleum era is expected to come to an end in this century, as there will no longer be enough. Gas, coal and electricity will replace some oil as it becomes scarcer during the transitional period before new sources are gradually developed.There is a critical need for energy conservation in the short term. Conservation will, to a great extent be justified by savings, as it will be less expensive to recover energy that is being wasted than to acquire additional energy.The gradual development of new technology is expected to increase energy self-sufficiency in the long term. New energy sources are attracting a growing interest and are becoming more economically feasible and marketable. These rediscovered energy sources include peat, wood, solar, domestic waste and windmills.The sudden increase in energy prices has forced users to look at the way energy is used and find ways to save it. Major industries have found that using separate meters for each department spurs energy responsibility. Energy trim programs now rank in importance with profitability, productivity and with quality.Energy has become such a crucial cost element that better data are essential for planning. Data acquisition varies with plant size and number of utilities. Meters can be read manually or monitored by computerized energy management systems.The relationship of electrical energy input and production levels for a typical uranium mine will be used to demonstrate two steps to energy management. The first step reduces demand through peak load control; the second reduces the waste of energy by monitoring energy used per unit of production.The direct benefit of saving energy is the money saved."

Jan 1, 1980

By U. C. Tainton

The paper reviews the evolution of electrolytic zinc, describing some of the major obstacles that have been encountered and overcome. The chief remaining limitations of present-day standard practice are: Difficulty of obtaining high extractions, especially from low-grade and complex ores; filtration troubles, if ores contain much soluble silica; and irregularities in electrolysis, if more than certain limited amounts of antimony, arsenic, cobalt; etc., are present in the ores. These factors dictate a relatively high-grade plant feed, thus subjecting the electroytic-zinc process to the same kind of limitations as the zinc smelter. The "high acid process," in which both acid strength and current density are raised to about four times the usual figures, is described. This system concentrates both plant and operations, allows a simple type of flow sheet, and. minimizes some of the difficulties above mentioned. The large-scale operation of the process is described. SOME time ago, at a meeting of the Institute Prof. J. W. Richards1 said, "I take exception to the statement that all the factors in the production of electrolytic zinc were known long ago. There is possible in my opinion an improvement of perhaps 50 per cent. in the new electrolytic processes." An examination of the literature of the subject will show the justness of Professor Richards' contention. The work of the earlier investigators was carried on in the shadow of difficulties that, today, are hardly more than memories. We seldom hear now of zinc sponge, that bête noir of the electrolytic-zinc pioneers. Zinc sponge, was the name given to a peculiar, soft, black, non-adherent form of zinc deposit that was utterly useless for melting into ingot form. At the big plant at Cockle Creek, New South Wales, in 1897, Edgar Ashcroft2 said that the solution in the plant would suddenly, and without ascertainable cause, go "bad" and begin to deposit spongy zinc. The most delicate, even spectroscopic, methods of analysis were unable to detect any difference between "good solution and "bad" solution; either form might change to the other on being kept for a while. When it is added that an outbreak of this insidious disease (which. appeared to

Jan 2, 1924

By Henry Brehaut

"It is difficult to know how much environmental information is absorbed by those in a position to put it to use. The following information may seem like ""old stuff"" to those whose companies are taking steps to improve their environmental performance. This paper is directed in particular to those people who are interested in determining what further changes are required to make improvements as concerned environment citizens.IntroductionUntil recently, the author was comfortable with the fact that none of the operations for which he was responsible had any environmental charges against them. It was not until one of his operations was charged with non-compliance that the author discovered due diligence as a way to avoid a second charge, and when an unfortunate spill occurred at another operation, the meaning of risk prevention was learned. Knowledge was gained step by step to the point where finally environmental information is being heeded, rather than waiting to learn from sad experience. With the appreciation of what it takes to do a good environmental job, comes an understanding of the challenge that lies ahead, and the fact that there is a lot to learn.At a recent environmental gathering, comments from the participants varied considerably. Some just didn't understand why government was being so unreasonable, while at the other end of the spectrum one individual whose company was well along the path to becoming a good environmental citizen remarked that it was all very basic. What was immediately understandable to one went right over the heads of others, indicating the different stages that have been attained in the acceptance of environmental responsibilities."

Jan 1, 1991

By Derek Harvey

"The paper briefly describes the development of the Eickhoff ESA60 roadcutter which is based on the old and well used principles of the shearer loader. It is intended to show that the machine offers a viable alternative to the normal methods used for driving roadways and also for coal production . References are made to installations currently operating in Europe with applications ranging from roadway drivage to pillar recovery. The paper also looks at possible applications in Canada.IntroductionThis paper is an attempt to show how the principles used in mechanical cutting, conveying and roof support are being applied to a development system capable of catering to a variety of situations and conditions. It is also intended to illustrate how the same system can be used as a total mining system for the mining of many minerals.In order to give some sort of time perspective to the age of the principles, reference can be made to an article in Coal Mining & Processing which states:- During World War II the Germans developed the "" panzer"" or armoured face conveyor.- After the war the English developed power cutters or trepanners that were mounted on the face conveyor, this then developed into the shearer.- The first shearer was produced by the Anderson Company in England in 1950 and shortly after that the Eickhoff Company started manufacturing shearers in German y.- The first hydraulic roof support was produced in 1954 by Gullick.This is a potted history of the three major components of the new system, i.e.:- Mechanical cutting element based on the shearer.- Transport element based on the panzer.- Optional roof support based on the hydraulic face supports.It can therefore be said that since the "" youngest"" of the elements was produced in 1954 the principles of the system in respect of the rapid change in mining equipment are in fact old.Of the three major components the most important is the cutting element since the major benefits of the system are to be obtained from this."

Jan 1, 1985

By J. B. Cohen, O. F. Kimball

Aging of specimens of Au-20 at. pct Ni and Au-40 at. pct Ni has been followed with electron microscopy, resistance, magnetic measurements, and X-ray diffraction. The periodic structures observed by electron microscopy in Au-Ni alloys by Fisher and Embury are shown to be due to nickel-rich prepre-cipitates. Assuming this alloy system undergoes spinodal decomposition, our observations and available data on thermodynamic properties and elastic constants indicate that the gradient energy coefficient in this system is of the order of 10-5 ergs cm-1 . Shifts of X-ray peaks in this system have been found to be due primarily to residual stresses, not faulting. A large effect of applied stress during aging was detected by X-rays and electron microscopy for the Au-20 at. pct Ni alloy. The presence of a preprecipitation stage during aging of gold-rich Au-Ni alloys for short times below 300°C has been indicated by several previous investigations. Changes in electrical resistivity,1"3 elastic modulus,4 superparamagnetisrn,5 positions of X-ray diffraction peaks,6 and hardness7 have been studied. Electron diffraction and microscopic studies by Fukano8 and Fisher and Embury9 respectively showed that the precipitation process resulted in the formation of periodic composition fluctuations—perhaps spinodal decomposition. MOSS10 detected a satellite with X-rays in quenched specimens, but the wavelength was much smallerthan that found by Fukano. Recently Woodilla and Averbac11 detected a modulation similar to that found by Moss, but with electron diffraction. They suggested that the microstructures observed by Fisher and Embury may be simply due to a Moir'e effect from a back deposit of gold during electropolishing. Satellites in electron diffraction can be enhanced by small bends or tilts of a foil. Even if this were not the case, asymmetric satellites, as are found in Au-Ni are difficult to analyze. They are principally influenced by the large differences in atomic size in this system, and obtaining information on the associated composition fluctuations depends on assumptions as to whether or not there are isolated clusters or composition "waves", and in the latter case whether or not the entire specimen has decomposed. Assuming that decomposition was complete in alloys aged at low temperatures, Woodilla and Averbach suggested that the satellites indicated a composition which varied about the average value by only± 5 pct, much less than that predicted from the phase limits, Fig. 1; they attributed this small variation to a cessation of the reaction caused by the loss of mobile vacancies. In Ref. 12 it was shown that vacancies are trapped by the preprecipitate in this system. Furthermore, after reversion, aging proceeds at a much slower rate than immediately after a quench from the solution temperature,5'11,13 indicating the importance of vacancies in the kinetics. In some senses Au-Ni is a favorable system for studying preprecipitation and reversion mechanisms because of the simplicity of the equilibrium diagram14 and the availability of good thermodynamic15 and diffusion data.16,l7 The calculations necessary to relate the decomposition process to classical nucleation and growth or to spinodal decomposition, as well as those necessary for understanding reversion mechanisms, can, therefore, be made. As an example, the position of the chemical spinodal, calculated from the thermo-dynamic data of Sellars and Maak15 with the method described by Rundman and Hilliard,18 is included in Fig. 1. It is compared to the chemical spinodal calculated from the equilibrium miscibility gap by Cook and Hilliard's method.l9 Included is the coherent spinodal suggested by Golding and MOSS," using measured elastic constants for their calculations and the same ther-modynamic data. The spinodal estimated by Woodilla and Averbach,11 by determining the temperature limits for the observation of the satellites discussed above, is also given. Actually this last curve is open to question on the following grounds: As a phase boundary is approached the spacing of particles or the wavelength

Jan 1, 1970

Jan 1, 1902

By P. Venkatasubramanian

"In recent years, computer based ""expert systems"" have been taking on large complex tasks for which no exact algorithmic solutions are feasible; tasks previously reserved for human experts requiring empirical knowledge, judgment, experience, developing a ""best solution "" by the use of plausible reasoning. Mining method selection is an appropriate area for the application of an expert system because extensive and detailed knowledge is required to make a ""best"" interpretaion of frequently ambiguous geological information. The expert system model presented here would enable users to apply expert knowledge to the evaluation of methods for coal deposits mineable by underground methods. IntroductionIn an increasingly complex and specialized world, human expertise spanning scientific, economic, social and political issues plays an increasingly important role in all branches of engineering. This is especially true of mining engineering. The number of scientific and professional disciplines involved in mine planning and evaluation, illustrates the problem. A conservative list includes geology, geophysics, geotechnics, hydrology, mining, environment, and economics.Engineers are almost obliged to be experts in at least one of the above disciplines if they are to handle the volume of information required in the planning process. Although computers have become indispensable tools in many endeavours, there is continued reliance on the human expert's ability to identify and synthesize these diverse factors, to form judgments, evaluate alternatives , and make decisions . This is especially true with regard to problems that are not easily amenable to precise formulations.The precious resource of human expert is also fragile and transient. The departure of a crucial expert from an organization ma y cause serious dislocations. Senior experienced people impart their knowledge of younger colleagues, but the demand for their talent may not leave sufficient time for such educational efforts. In recent years, computer based "" expert systems"" have been taking on large complex tasks for which no exact algorithmic solutions are feasible; tasks previously reserved for human experts, requiring empirical knowledge, judgment , experience, developing a ""best solution"" by the use of plausible reasoning."

Jan 1, 1988

By Arnulf Muan, Klaus Schwerdtfeger, L. S. Darken

The equilibrium ratios CO/CO, of. a gas pharse coexislitrg with selected oxide phase assemblages of the system "FeO"-MnO-SiO2 and metallic iron have been determined at 1150°C. The data obtained are combined wilh the thermodynamic data on fayalite (Fe2SiOi) and "FeO"-MnO solid solutions to derive the actiuity-coiHpQsiUon relations for the various oxide components of the olivine (Fe2SiO4-,lIn2Si04) and pyroxenoid (standard free energies of formation of ferrosilile (FeSiO,), tephroite , and rhodonite from their oxides have been evaluated. In the Appendicc~s by Darken and Schivcerdtjeger the ideal solution law for solid deri oed. THE quaternary system Fe-Mn-Si-0 is of interest in many important phases of iron- and steelmaking. For instance, reduction in the blast furnace of ores containing Fe-Mn silicates, deoxidation of liquid steel with Mn-Si alloys, formation and subsequent alterations of oxide inclusions in steels, and the oxidation of manganese- and silicon-containing steels during processing are all governed largely by the thermodynamic relations existing in the system Fe-Mn-Si-O. Although the equilibria between liquid iron and Fe-Mn silicates have been studied in detail previously,' experimental data are lacking for equilibria among the solid phases. The present paper provides such data for a selected temperature, 1150°C. I) PREVIOUS WORK The general feature of subsolidus phase relations in the system iron oxide-manganese oxide-silica under strongly reducing conditions is known.' Fig. 1 represents an isothermal section at 1150°C. The phases present, in addition to silica, are three solid-solution series, viz.. the oxide solid-solution series "Fe0"-MnO (manganowiistite), the orthosilicate solid-solution series Fe2SiO4-Mn2SiO4 (olivine), and the metasilicate solid-solution series FeSi03-MnSi03 (pyroxenoid). The "FeO"-MnO solid solution is continuous between the two end members wustite and manganositeV3 as is the orthosilicate series between the two end members Fe2SiO4 and Mn2 SiO4. 4 The metasilicate solid solution, on the other hand, extends only part way from the MnSi0.l end member toward FeSiO because the latter end member is unstable relative to the phase assemblage fayalite + silica. The letters a through m in Fig. 1 identify end members of the individual solid phases dealt with [for instance, c designates fayalite (FeZSiO4) in equilibrium with wustite, e designates fayalite in equilibrium with silica, and so forth]. In addition to the phase relations there are some thermodynamic data available for the end members of the silicate solid solutions and for the "FeO" -MnO solid solution. The free energy of formation of fayalite (Fe2Si04) from its oxide components has been studied by several investigators. Unfortunately, the data obtained show considerable discrepancies. According to recent tabulations by Kelley, the change in standard free energy Affn for the reaction

Jan 1, 1967

By Frank R. Field, Joel Clark, Walter C. Labys, William A. Vogely

Mineral models provide a systematic and comprehensive approach for analyzing and fore- casting the behavior of mineral markets and industries.' They also permit the analysis of a wide range of policy decisions. Obviously such models cannot capture all of the intricate relationships that shape the behavior of a mineral market. However, such models have become extremely useful and in many cases support the decision making approach of judgmental analysts. They tend to narrow the range of likely outcomes and thus reduce the risks and uncertainties of investing, trading, and speculating in minerals. Mineral models provide not only answers to "what-if" questions, they also inform analysts of the benefits and costs associated with mineral investment decisions. More recently they have been applied to specific mineral issues of the possible impact of buffer stock stabilization schemes and of import supply restrictions. Mineral Models Defined Because mineral models are so diverse, we must begin with a fairly broad definition. A mineral model is a formal representation of a mineral market, industry or system where the behavioral relationships included reflect the underlying economic and engineering factors as well as the political and social institutions. Of ten, but not always, a mineral model will consist of some combination of the following components: demand, supply, inventories and prices. Modeling of demand behavior normally begins with an interpretation of basic demand responses to prices and income (i.e., the associated price and income elasticities). Price elasticities vary among different minerals and among their diverse uses. They tend to be lower for minerals without close substitutes than for those where such substitutes exist. In addition, these elasticities vary with time as well as with the actual excess demand or excess supply. Variations like these, coupled with the relative instability of prices for a number of minerals, make explanations of demand behavior difficult. The degree to which demand responds to changes in income depends on the income elasticity of the end products to which the minerals serve as inputs. Those products with a relatively low income elasticity tend to experience proportionally smaller swings in sales than those with higher elasticities. The transmission of demand cycles to minerals producers comes through a series of stage-of-process effects. Demand measurement also is influenced considerably by mineral substitution patterns. The cross-price elasticity of a competitive or complementary commodity also varies with minerals, markets, and time. Where minerals easily substitute for one another, as in the case of cop- per and aluminum in electrical conductor applications, cross-price elasticities are relatively high. Modeling of mineral supply behavior normally involves consideration of resource development, economic conditions, geologic

Jan 1, 1985

By Robert B. Schluter

The Bureau of Mines investigated separating copper-nickel mattes to recover a copper-rich fraction suitable for processing by conventional copper metallurgical processes and a nickel-rich fraction suitable for processing in a hydrometallurgical nickel circuit. Distribution of cobalt and precious metals between the copper and nickel fractions was also determined. A matte containing a nominal 65 pct Cu, 9 pct Ni, 4 pct Fe, and 20 pct S was separated into a copper fraction that comprised 80 pct of the matte weight and contained 70 pct Cu and <1.5 pct Ni, plus a nickel fraction that contained 40 pct Ni and 30 pct Cu. Recoveries of copper and nickel into their respective fractions were 90 pct and 87 pct. These results were obtained in a laboratory flotation cell at a matte grind of 90 pct minus 500 mesh and a pH of 12.4, using 1.7 pounds DPG (diphenylguanidine) per ton of matte as collector and frother. Magnetic separation was used to remove metallic iron-nickel alloy from the copper fractions. Distribution of cobalt was about 70 pct to the nickel fraction and 30 pct to the copper fraction. Silver reported predominately to the copper fraction, while Au, Pt, and Pd were essentially entirely recovered in the nickel fraction.

Jan 1, 1982

By George F. Becker

A Nere record of Emmons&apos;s professional career would very inadequately represent the man. That he was eminent mc know, and our successors will realize in due time; but they must depend upon us for knowledge of a singularly ~vholesome, modest, unselfish personality, and of a character that did honor to a profession in which trustworthiness is indispensable. Those members of the Institute who met Emmons are his friends, and I never knew .one of these who was not the better for that friendship. Emmons was born in Boston, Mar. 29, 1841, the son of Xathaniel H. and Elizabeth (Wales) Emmons, and was named Samuel Frankliri after an ancestor who was of the sarne family as Benjamin Franklin. He took the degrcc of Bachelor of Arts at Harvard in 1861, and soon afterwards went abroad to complete his education. From 1862 to 1864 he attended the courses at the fieole Impkriale des Mines at Paris, Elie de Beaumont arid Daubrke being among his professors. The year 1864-1865 he spent at Freiberg under Cotta and other famous teachers; after which he spent another year in traveling through Europe. Like many other renowned geologists, he approached his ultimate profession from its economic side, and was thus from the first imbued with a sense of high responsibility in the promulgation of scientific opinions or conclusions. With hypotheses which were interesting merely because they were ingenious or even plausible, he would have nothing to do. In 1867 he joined the Geological Exploration of the Fortieth Parallel at its organization under Clarence King, serving at first as a volunteer, but soon receiving a regular appointment. This expedition was the first one of purely geological character sent out by the United States government. As Emmons has shown in his admirable presidential address on " The Geology of Government Explorations," its work was founded on a com-

Jan 1, 1912

By A. S. Richardson

AIR conditioning, or air cooling, for the improvement of ventilation in the Butte mines has come into increasing use during the past 10 years. In part, the methods practiced have been described in previous publications of the Institute, but some improvements on earlier methods have been made and a number of new features have been developed. This paper is presented as a record of progress made, and for the sake of completeness describes all general features of the work. The need for air conditioning in the ventilation of mines in the district arises from the fact that the temperature of the ground and mine water has shown a very great increase with increase in mining depth, and has now reached a maximum of slightly over 130°F. The most difficult part of the ventilation problem is the maintenance of temperature and humidity of a satisfactory standard in the working places, especially on the lower levels. Although ordinary ventilation is adequate to maintain good conditions in most of the working places it is subject to a number of limitations at great depth. Most important among these limitations is that with increase in depth the air becomes heated before it reaches the working places, both by compression from increase in atmospheric Pressure and by heat transferred to it from rock at high temPerature, so that its capacity for lowering temperatures is greatly reduced before it reaches the operating zone. Increasing depth of mining also increases the distance traveled by the air in its passage through the mine, and this causes a corresponding increase in resistance to air flow, so that there is greater difficulty in maintaining even the same volume in circulation. Thus, in the face of a demand that the ventilating system have a very much greater capacity to remove heat from the mine, the tendency is for that capacity to diminish. The only evident alternatives were (I) the opening of additional air shafts to increase the volume of air in circulation, (2) an extension of the existing system that would be subject to the same limitations, or (3) the adoption of an entirely different method such as air cooling. Fortunately for an economic solution of the problem, the mean annual temperature of the surface atmosphere at Butte is about 40°F., with very low relative humidity in summer, so that there is unlimited natural cooling power at a temperature range adaptable to air-conditioning methods. Methods Two similar methods of air conditioning are used, as necessitated by service requirements and dependent upon the equipment available. In one, which is the more important and has the greater cooling capacity, water is circulated in a closed circuit, and, alternately, first absorbs heat from warm mine air and then dissipates it in the surface atmosphere by cooling at a cooling tower. The second

Jan 1, 1943