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By R. H. Winn

A method for the selection of the most suitable corrosion inhibitor for a particular system is given. The method involves the evaluation of surface passivity by means of copper ion displacement after the metal surface has been subjected to the corrosive atmosphere. The application of the method to the selection of suitable inhibitors for use in producing wells is described. Correlation with recognized laboratory tests has beet1 found to be good within the limitations of the test. The use of the test to evaluate inhibitor persistencc is described. INTRODUCTION Corrosion as it is associated with the industry shows wide variations in its qualitative as well as its quantitative aspects. This complicates the work of the corrosion engineer. In the past few years the efforts of the corrosion engineer have been further taxed by the large numbers of products being marketed as corrosion inhibitors by various manufacturers. These products are submitted to him together with a limited amount of data to support their use as inhibitors. The data are usually authentic and reliable yet all too often when these products are applied to an actual corrosive system the results are disappointing due to the ineffectiveness of the inhibitor and the corrosive system. The corrosion engineer must select a comparatively limited number of inhibitors for field trial from the large number available. The selection is usually made on the basis of a standardized laboratory test such as that adopted by the National Association of Corrosion Engineers or by field experience in an area; however, testing of this type is discouraging on large numbers of compounds, particularly in view of the specificity of environment. It has been an object of this work to devise a method which will allow the corrosion engineer to select the best inhibitor for a specific environment under field conditions. The test would of necessity be rapid and inexpensive. It would preferably eliminate the need for expensive and delicate instruments. STATEMENT OF THEORY The test as developed makes use of the fact that metal ions will be displaced from solution by metals having a more positive electrode potential. Thus, if an active iron surface is exposed to a solution of a copper salt, free copper will plate spontaneously on the iron surface as it is displaced from the salt solution by iron ions. If the iron surface is passified, as by coating with an insulating-type organic corrosion inhibitor, it is no longer capable of displacing the copper ions due to its own limited ionization. The result will be a change in the amount of copper plated upon exposure to a neutral copper salt solution. In practice it has been found possible to measure the magnitude of the alteration of the cell potential by determining the copper deposited on a standard iron surface under controlled conditions. This means that, as the film builds up, the resulting shift in the electrode potential tends to cause the iron surface to act more like a noble metal, resulting in a reduction in the cell potential to a point that copper will no longer plate spontaneously. Obviously, the salts of other metals such as silver, gold or platinum might be used for this operation; however, copper was selected because of the color difference of the plate, the comparatively low cost of copper salts and the ease of evaluation of the plated copper. Furthermore, its high cell potential provides a substantial driving energy. The determination of the copper is readily done colorimetrically by dissolving it in 5 per cent ammonium hydroxide solution containing 2 per cent potassium per-sulfate. The blue color of the copper ammonic complex ion so developed may be compared with standards prepared by dissolving known quantities of copper powder in the same reagent. In routine screening it is seldom desirable to determine the amount of copper plated. It is usually more important to determine the concentration of inhibitor required to prevent the plating of copper.

By R. S. Olson

An analysis of the wash thickener-two stage filtration circuit was undertaken to quantitatively describe the circuit performance. On the basis of information developed in this study, the factors of major importance in reducing soluble loss are: filter wash, wash zone size, filter capacity, filter feed pulp dilution, blow back, filter cloth, water to repulp, water to primary wash, water to feed pulp and thickener underflow. The wash thickener-two stage filtration circuit has been used in many hydrometallurgical plants to separate solute from leach solids. As many as 20 to 30 plant operating variables determine the performance of the wash circuit and hence the soluble loss. The complex relationships of these variables, with each other and with soluble loss, make the evaluation of their effect on mill performance difficult. An analysis of this type of circuit was undertaken to quantitatively describe the circuit performance. THE CIRCUIT The diagram in Fig. 1 represents the operation of the wash thickener-two stage filter circuit. This circuit provides for counter current, cross current or for a combination of countercurrent-cross current operation. The feed pulp stream, J, is intended to include any solution or water, other than primary and secondary filtrate, which enters the wash thickener. Except for filter washing, the operations in the circuit are simple mixing operations which can be described by material balance. The concentration of solute in the filtrate and cake solution after application of wash liquor cannot be described by simple material balance. The displacement washing equation, derived by Rhodes1 and extended by Choundhury and Dahlstrom,2 appears to best describe this case of miscible displacement in porous media. In a useful form, it is

Jan 1, 1963

By Frank E. Woolley, Robert D. Pehlke

Jan 1, 1965

By Henry G. Granger

I. INTRODUCTION. REPEATED failures in attempts to work gold-bearing gravels by means of suction-dredges have created the impression that this method is impracticable. The suction-dredges have failed from three special causes excessive wear and frequent breakage of pump-shell, runners and liners; inability to dredge compact gravel which would ,not. readily move towards the intake; and, most important of all, closing. of the suction-pipe by stones too large to enter it. In my opinion, all three causes of trouble may be remedied: the first, by making stronger the parts most liable to wear and breakage; the second, by means for loosening the gravel at the intake; and the third, by sufficiently... Increasing.. the diameter of the suction-pipe. In suction gold-dredges, this diameter has not usually exceeded 10 or 12 in.; whereas there are few profitable gold-fields which can bee considered dredgeable, in which stones more than' 12 in. in diameter, are-.not frequently encountered. II. AN EFFECTIVE SUCTION-DREDGE. In harbor-operations, much larger stones are handled by suction-dredges.., The large dredge of the Henry Steers Contracting Co. worked for nearly four years at League Island, Philadelphia, where it sucked up, passed through the pump, and forced through 3,700 ft. of discharge-pipe; gravel containing boulders up to 200 lb. in weight. This was done with no bad breaks and few shut-downs. The cutter; and liners were the only parts liable to damage, and these were easily replaced with brief interruption of work. The chrome-steel liners are said to have lasted from six to nine months. I am informed that this dredge worked continously for nine

Apr 1, 1909

By L. F. Elkins

In 1946 Littlefield, Gray and Godbold published a thorough geologic description of the West Edmond Hunton Lime reservoir, located in Central Oklahoma, and discussion of its early performance.l They stressed implications of the nature of the reservoir rock on performance to be expected with production both by natural means and by pressure maintenance with gas injection. The essence of their analysis was that presence of an extensive interconnected system of fractures and solution channels constituting about 10 percent of the total reservoir void space in otherwise very low permeability reservoir rock would result in severe channeling of naturally encroaching water or injected gas through the fractures with little or no benefit to ultimate recovery of oil. Considerations were in progress to unitize the reservoir for pressure maintenance by gas injection. Some other engineers involved in the project had considerably different opinions at the time regarding continuity of fractures and regarding effects of such fractures on performance. The field was unitized Oct. 1, 1947. Subsequently, pilot gas injection tests were conducted in four areas of the field; large scale waterflooding was conducted in two parts of the field in the Bois d'Arc or Upper Hunton; and pilot waterflooding was conducted in the Chimney Hill or Lower Hunton. Full scale water-flooding is now in progress in the Chimney Hill section where it is oil productive. The primary purpose of this paper is to divine some of the secrets of this reservoir through analysis of all aspects of its performance, with the hope that it will be of help to engineers and operators in developing and operating other low permeability fractured reservoirs. In part, this considers variance of actual performance from some widely used conventional reservoir engineering assumptions. For brevity, other aspects of unit operation and its benefits to the owners are not discussed. Oil and Gas in Place For unit participation, net pay in the Bois #Arc defined by the gross SP anomaly on electric logs totalled 2,100,000 acre-ft in the 30,000-acre reservoir. Development of West Edmond predated modem logging techniques that now would be used to determine "net" or "productive" pay. In Fig. 1 this log pick is compared with detailed core analysis and core descripfion by Littlefield et a1.l for one well identified as A on the index map in Fig. 2. Not all of the gross Bois #Arc section had oil staining, but all cores with measureable intergranular permeability were stained. (The committee selection of the Bois d'Arc SP interval also includes the Frisco section as identified from cores by Littlefield.) The Bois d'Arc is oil productive throughout the entire 600-ft monoclinal accumulation from the eastern upstructure erosional pinchout to the west-side oil-water contact. (See Littlefield et al.l and McGee and Jenkins for geologic detail.)

Jan 1, 1970

The income of the Institute is derived from dues, subscriptions to MINING AND METALLURGY and sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion constituting endowments for especial purposes. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd Memorial Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization.

Jan 1, 1936

By D. J. Coolidge, H. L. Sheakley

THIS paper does not deal with all sands used in the glass industry in Missouri; it covers only that used in the plate-glass factory at Crystal City. However, it is probably safe to say that other sands, pro- [ ] duced throughout the state for this purpose, are of identical nature. The glass sand used in Missouri is commonly called the St. Peter deposit, which is ascribed to the Ordovician Rock series in the form of sandstone. This St. Peter deposit, aside from a few small outliers, covers a large area of eastern Missouri. It forms, through a broad curve, the northeast margin of the typical Ozark region between Cape Girardeau on the southeast and Mineola, Montgomery County, on the northwest. The belt is extremely irregular, varying from one to ten miles in width; its length is 150 miles in a straight line. [ ] The outcrop near the entrance to the Crystal City mine appears in the form of a sandstone bluff approximately 30 ft. high, running along Plattin Creek (Fig. , I). Above the sand rock an overburden of Joachim limestone appears, which, thickens to nearly 300 ft. and forms the hill commonly called Buck Knob. Test holes, where drilled at various points and the drillers' log indicate that the St. Peter deposit ranges in thickness from 63 to 71 feet. PROPERTIES OT THE ST. PETER SAND From an analysis of the glass sands of the St. Peter formation in Missouri, the follow-

Jan 1, 1942

By D. H. Gurinsky, D. G. Schweitzer

The empirical equilibrium constantsd the heat of reaction for the reduction have been determined from 300° to 500°C. The mechanisms of the oxidation of uranium and magnesium from dilute bismuth solutions have been investigated. The kinetics of some of the reactions were affected by air adsorbed on the uranium oxides. THE Liquid Metal Fuel Reactor studied at Brook-haven National Laboratory uses a solution of uranium in bismuth as the fuel. Corrosion and stability problems require that the fuel solution contain corrosion inhibitors and deoxidants. Of the additives tested, magnesium has been found to be the best deoxidant and zirconium the best corrosion inhibitor in bismuth. Some experiments1 indicate that magnesium may play a secondary role in increasing the effectiveness of zirconium in inhibiting corrosion. The work reported here was intended to determine the relative concentrations of Mg and U required to prevent oxidation of the uranium fuel in the event of an air leak. In addition, an attempt was made to identify some of the mechanisms of the oxidation and reduction reactions occurring in the liquid bismuth solutions. EXPERIMENTAL Apparatus and Procedure—The equipment shown in Fig. 1 was designed so that the reaction kinetics could be studied as functions of temperature, melt composition, pressure, and flow rate. At the start of a run, the 10-liter bell jar (F) is removed by opening the bottom Dresser fitting (L), and the bismuth and additives are placed in a pyrex crystallizing dish (I). The bell jar is replaced, the system is evacuated to 10-5 to 10-6 mm Hg and then the heater (J) is turned on. When the selected temperature is reached, the oxidizing gas is admitted to the system to the desired pressure as read on the manometer (D). Gas is introduced through the slide tube (Q) which has a pyrex frit (R) sealed to its bottom. Stirring is accomplished by immersing the end of the tube in the melt. To maintain a constant pressure under flow the input and evacuation rates must be equalized. To obtain this condition stopcock (C) is closed and flowmeters (B) are matched. The reaction is "stopped" by closing the inlet flowmeter and quickly evacuating the system. To obtain a liquid metal sample, the system is evacuated with the sampler positioned near the surface of the liquid. The sampler, Fig. 2, is then immersed until its thermocouple reading matches thermocouple (G) Fig. 1. The system is then pressurized with helium which forces the solution through the frit. Twenty to 30 min elapsed between the time the system was evacuated and sampled. During evacuation and pressurization of the system, the temperature variations did not exceed ± 5°C. While bubbling occurred the temperature remained constant to within 1/2 oC. The volume of the equipment was determined by adding a known volume of air at atmospheric pressure to the evacuated system and noting the resulting pressure.

Jan 1, 1962

By R. G. Bentsen, D. A. T. Donohue

The cyclic steam injection process has become the most widely applied and most successful thermal recovery technique in use today.1-4 Normally, steam stimulation is repeated several times during the life of a project. The problem is to select the optimum number and size of steam treatments so that the profits realized over the entire life of the project are maximum. Obviously, operating costs rise directly with the frequency and amount of steam injection. Operating efficiency, on the other hand, can be adversely affected if the amount and frequency of stimulation are insufficient. Thus arises a multistage decision problem; that is, a decision must be made at each sub-period (day, for example), as to whether steam should be injected, and, if so, how much. It is desirable that these decisions be made in such a way as to secure maximum net profit before taxes. This can be achieved by dynamic programming. To use dynamic programming, we must be able to predict not only the production rate-time curve resulting from a given stimulation, but also how changes in stimulation policy will affect this curve. In this study, the effect of steam injection on well performance is estimated on the basis of a simple model that takes into account both steady-state and transient flow. Oil production rate is calculated for both types of flow, and the larger of the two values is used. This allows the calculation to change to radial steady-state flow at such time as this mechanism becomes more effective than the transient mechanism. We propose to show how dynamic programming can be used to optimize the steam soak process with respect to net profit. For this, a mathematical representation of the steam soak technique is necessary. A further objective, therefore, is the formulation of a mathematical model capable of realistically simulating the physical process. Oil Production Response Model The advantage of using a mathematical model is its generality and ease of manipulation. However, the model must be an accurate representation of the physical process, for a solution derived from a model can be no better than the model itself. The question now arises as to how well the model should be expected to simulate reality. In general, the simplest model should be tried first, for additional accuracy is apt to require additional cost and time. Also, the search for a high degree of accuracy may yield only greater complexity and difficulty without yielding significantly better results. With this in mind, we kept our model as simple as possible, yet generally representative of the actual physical process. The number of state variables is limited to three, and stochastic variations in the parameters are ignored. As a consequence, use of this model should be restricted to cases in which the underlying assumptions are not severely violated. In

Jan 1, 1970

By J. P. Carson

The works of the Tula Iron Company are in the Republic of Mexico, State of Jalisco, twenty-eight leagues southwest of Guadalajara, ten leagues northwest of the town of Sayula, through which passes the projected line of the Mexican National Railroad. Its geographical position would be about: latitude, 20' 10' N., longitude, 40 35' w. of Mexico City. The surrounding country is a rolling plateau, 6000 feet above the sea, enjoying the most magnificent climate in the world, the average temperature being about '70'. The works were commenced in 1850 by a company with very small capital, having not the least idea of the undertaking. They soon fell into the hands of the money-lenders, and after changing

Jan 1, 1879

By Leo F. Reinartz

It was with humility that I accepted the invitation of the Board of Directors of our Institute to deliver the Twentieth Howe Memorial Lecture. Many previous lecturers could speak from personal experience of the great work done by Professor Howe. It was not my privilege to be one of his students but, indirectly, I came under the influence of his work many years ago. My mentor in Metallurgy at Carnegie Institute of Technology, Prof. Fred Crab tree, was an ardent admirer of Professor Howe and his work. Professor Crabtree taught me early to appreciate Professor Howe's love of truth and keen desire to find a scientific reason for every metallurgical phenomenon. In this early search, Professor Howe encountered many unexplainable facts. Nevertheless, in the classic text, "The Metallurgy of Steel," published in 1891, he indicated that he believed Research could light the way. Under the heading of "The Treachery of Steel" he said: "In the early use of Bessemer and Open Hearth Steel, many then unexplained and hence mysterious failures occurred. With our present knowledge, an easy explanation of most of them would probably have been seen. But even today certain unexplained and apparently inexpli- cable failures occur in steel; inexplicable in spite of full and intelligent investigation." Then Professor Howe continued to talk about "the trustworthiness of steel" in the following manner: First, the steel-maker has learned by experience. He knows today far better the effects of a high percentage of carbon or of phosphorus; of cracks, pipes and blow-holes; of segregation and imperfect mixing; of over-heating; of finishing too hot or too cold. Knowing, he guards against them more effectually, and keeps at home much steel that he would formerly have sent into the market. Those who would not, or could not learn and do, have been driven out of the business; the conditions necessary for producing good sound steel by the acid Bessemer and the acid Open Hearth processes have been mastered. By and by, the basic process came along with new conditions, new liabilities to unsoundness, a great hue and cry about mysterious fractures followed, and Lloyd's register provisionally forbade the use of basic steel. Much basic steel was irregular and brittle throughout; too much carbon, too much phosphorus, too cold teemings—imperfect mixing. Still there was little doubt that, with further experience, these difficulties of the basic process would be mastered as those of the acid process had been. This shows that Professor Howe could not take anything for granted. Believing that careful research would find the answer to all mysterious phenomena, he was several generations ahead of the practical acceptance and adoption of this principle.

Jan 1, 1943

By Leo F. Reinartz

It was with humility that I accepted the invitation of the Board of Directors of our Institute to deliver the Twentieth Howe Memorial Lecture. Many previous lecturers could speak from personal experience of the great work done by Professor Howe. It was not my privilege to be one of his students but, indirectly, I came under the influence of his work many years ago. My mentor in Metallurgy at Carnegie Institute of Technology, Prof. Fred Crab tree, was an ardent admirer of Professor Howe and his work. Professor Crabtree taught me early to appreciate Professor Howe's love of truth and keen desire to find a scientific reason for every metallurgical phenomenon. In this early search, Professor Howe encountered many unexplainable facts. Nevertheless, in the classic text, "The Metallurgy of Steel," published in 1891, he indicated that he believed Research could light the way. Under the heading of "The Treachery of Steel" he said: "In the early use of Bessemer and Open Hearth Steel, many then unexplained and hence mysterious failures occurred. With our present knowledge, an easy explanation of most of them would probably have been seen. But even today certain unexplained and apparently inexpli- cable failures occur in steel; inexplicable in spite of full and intelligent investigation." Then Professor Howe continued to talk about "the trustworthiness of steel" in the following manner: First, the steel-maker has learned by experience. He knows today far better the effects of a high percentage of carbon or of phosphorus; of cracks, pipes and blow-holes; of segregation and imperfect mixing; of over-heating; of finishing too hot or too cold. Knowing, he guards against them more effectually, and keeps at home much steel that he would formerly have sent into the market. Those who would not, or could not learn and do, have been driven out of the business; the conditions necessary for producing good sound steel by the acid Bessemer and the acid Open Hearth processes have been mastered. By and by, the basic process came along with new conditions, new liabilities to unsoundness, a great hue and cry about mysterious fractures followed, and Lloyd's register provisionally forbade the use of basic steel. Much basic steel was irregular and brittle throughout; too much carbon, too much phosphorus, too cold teemings—imperfect mixing. Still there was little doubt that, with further experience, these difficulties of the basic process would be mastered as those of the acid process had been. This shows that Professor Howe could not take anything for granted. Believing that careful research would find the answer to all mysterious phenomena, he was several generations ahead of the practical acceptance and adoption of this principle.

Jan 1, 1943

By R. Costantini

The author discusses the promising future of the use of pipelines for transportation of ore slurries over long distances, citing existing installations. Various criteria and factors affecting the use and size of pipelines are considered. Among the factors influencing the use of pipelines are particle size, specific gravity, abrasiveness, minimum velocities, and pumping considerations. Long-distance transportation of solids by hydraulic pipelines holds the promise of great economic benefits. Today within the confines of most mineral processing plants, the moving of solids about in slurry form by pipeline is commonplace, since the method offers great advantages when conditions are suitable. Yet, this method is surprisingly slow in being adopted on a broad scale for transportation of solids over long distances (arbitrarily the term will be applied to one over five miles long). This is especially surprising in view of the successful realization in this country within the last five years of two daring ventures in long-distance solids pipelines. A 72-mile long, 6-in. diam pipeline of the American Gilsonite Co. has been satisfactorily transporting 700 tpd of gilsonite from the mine at Bonanza, Utah, to the processing plant at Grand Junction, Colo., since April 1957. The 108-mile long 10-in. diam pipeline of the Pittsburgh Consolidation Coal Co. has been transporting about 4000 tpd of finely crushed coal from the mine at Cadiz, Ohio, to the Eastlake power plant of the Cleveland Electric Illuminating Co. on Lake Erie since January 1958. However, besides two projects in the operations of The Anaconda Co. there have been hardly any other significant solids pipeline developments in the minerals industry during the last three years. The two projects are the 14-mile long, 6-in. diam copper concentrate gravity pipeline at Anaconda's El Salvador project in Chile which has been transporting about 800 tpd since January 1959. The second is a 16-in. diam tailings pipeline at the Anaconda Reduction Works, Anaconda, Mont., designed to transport about 20,000 tpd of deslimed flotation tailings for dam building. This pipeline, which is currently undergoing tryout tests and which will be about seven miles in length, will have a maximum of three 20-in. rubber-lined centrifugal pumps in series at the starting point, each developing a maximum of 100 ft of head, to supplement gravity. It is the writer's opinion that the major reason for the hesitation in considering pipeline operations is confusion due to an inadequate understanding of the basic physical principles affecting the slurry flow process by many engineers in the industry. This in turn begets an attitude of fear and trepidation instead of confidence on the part of many management executives, which leads to a minimizing of the advantages and exaggeration of difficulties when considering the possibility of a long-distance solids pipeline. The promotion of better understanding and consequently the promotion of greater confidence in the potentials of long-distance solids pipelines when conditions are suitable is thus the main purpose of this article. To this end, after considering several examples of the possibilities for solids pipelines in the minerals field, the relative significance of the major factors affecting pulp flow, and some major aspects of slurry pumping will be discussed on a general qualitative level. Then a brief outline of the semi-empirical quantitative methods developed to date for estimating slurry flow behavior will be presented. SOME POSSIBILITIES To give an idea of the magnitude of the possible economic benefits, it should be interesting to mention briefly some of the projects currently under consideration and to suggest some likely future possibilities. At Anaconda's El Salvador Project in Chile (Fig. 1) it is eventually planned to extend the existing 14-mile pipeline by another 60 miles to bring the copper concentrates down to the coast of the Pacific Ocean. Preliminary tests indicate that the projected 6-in. pipeline will be able to transport approximately 2000 tpd of concentrates at a pulp density of 40 to

Jan 1, 1961

By H. R. Cooper

Beginning from the point of view that process control of ore flotation can be approached by on-line analysis of processing behavior, an equation was developed which has characteristics useful for a multi-variable feedback loop. The application of this equation to optimizing control with a data acquisition system will be discussed in Part 11. OBJECTIVE OF CONTROL The purpose of developing a feedback method for concentrator control is to provide a means for determining ore processing behavior in order that data describing the ore can be used to make appropriate changes in control conditions while the ore continues to flow through the flotation circuit. In absence of simple linear relationships between pairs of variables in the flotation process, attention is directed to the need for a generalized relationship which possibly would incorporate all pertinent variables. It would be possible to apply such an equation to the control of variables in a concentrator in real time according to operational requirements as ore gradually changes in quality and processing behavior. To meet this objective, it is necessary to define relationships describing flotation performance in terms of performance variables capable of being measured on-line, either with on-line instruments and analyzers or with manual methods lending themselves to quick determination of meaningful information. Relationships derived to meet this objective form a model for the flotation process. The evaluation of flotation parameters of the ore and the execution of control on the basis of the derived information while the ore is continuing through the process would constitute a feedback control system. Data for the following control and performance variables can be made available: 1) ore feed rate, 2) collector addition rate, 3) lime addition rate, 4) pulp density, 5) assay or multiple assays in feed, tails, or concentrate sufficient for material balancing, 6) particle size distribution in flotation feed, 7) froth height, and 8) frother addition rate. Other process variables, such as flotation air input and mechanical agitation intensity, are usually not considered as control variables and were not taken into account in this analysis. Other data, such as that describing the ore, would be useful for concentrator process control. However, information of this type (such as ore hardness, grain size of the mineral, chemical species of the mineral, and ore surface properties) being not presently measurable in the on-line sense, has the effect of causing disturbances in the system which can be detected only indirectly. The process control system being sought must recognize disturbances by their effect on measured performance followed by determining control changes to compensate for them in meeting the objectives of improved performance (perhaps higher throughput, maximum return, etc.). A suitable model for the process having capability of recognizing the effects of ore disturbances should provide the means for introducing proper compensation through control changes. This would be done by processing on-line data with the model to calculate coefficients reflecting ore characteristics. This procedure can only be applied in a typical flotation system when on-line data can be processed at faster rates than the usual rate at which the ore in flotation feed takes on significantly different characteristics. For example, material balance data can be accumulated in approximately 5-min intervals using on-line X-ray fluorescence analysis. The flotation system time constant might be 15 min including grinding. Ore changes having time constants longer than 1 hr could be accommodated using on-line feedback control by this procedure. FORM OF A FLOTATION MODEL A suitable form for mathematical expression of the flotation process is an equation involving rates, when each of the components entering into the separation can be treated independently by a rate equation. A first-order, kinetic rate equation can be written on

Jan 1, 1967

By S. H. Ward, R. A. Barker

THE Juniper Prospect is in Carleton County, N. B., at approximately 46" 31' north latitude, 67" 20' west longitude. During the summer of 1955 an area in west-central New Brunswick was selected for aerial electromagnetic prospecting with American Metal Co.'s helicopter-mounted equipment. Generalized, small-scale government geologic maps had suggested that this area was located along the western border of the northeast-trending granitic backbone of northwestern New Brunswick and might be underlain by the Ordovician-Silurian sediments and volcanics that are the host rocks for the recently discovered sul-fide deposits of the Bathurst-Newcastle district. The helicopter electromagnetic equipment located an anomalous conductive area, coincident with a small aeromagnetic closure, about five miles west of the town of Juniper. Subsequently 30 mining claims (total area about 6600 x 8000 ft) were staked and company personnel conducted geological, geophysical, and geochemical investigations on the property. The claims and immediately contiguous areas were mapped geologically, and an area of about 2000 x 4000 ft was soil-sampled and also surveyed by ground electromagnetic and gravity methods. Finally six diamond drillholes, totaling 3500 ft in length, were drilled to test the anomalous conditions discovered by the several exploration techniques used. The discovery of base metal sulfides during drilling was a technical success for the exploration methods, but the quantity of sulfides was too small to be profitably exploited.

Jan 1, 1959

By C. G. Cheriton

The Bathurst mining district is located near the town of Bathurst on the north shore of the province of New Brunswick in eastern Canada. This region is the northeasterly extension of the Appalachian mountain system. The area is heavily forested and covered with a fairly uniform layer of glacial gravels and boulder clay. The relief is low, increasing to a few hundred feet in the north west and several hundred feet in the extreme southwest. Thus, rock outcrops are scarce and occur mostly along streams and ridges. These factors made conventional prospecting difficult and resulted in the district becoming an excellent place for the application of regional geological studies, air photo techniques, airborne and gound geophysical methods and soil sampling. Late in 1952, The Brunswick Mining and Smelting Company discovered a very large base metal sulphide body presently known as their No. 6 orebody. Early in 1953, another and even larger sulphide body was discovered and is known as the No. 12 ore body. Mining exploration was very active thoughout 1953 and in 1954, The American Metal Company discovered the orebodies which have been developed into The Heath Steele 'Mines. The location of these deposits is shown on figure one. In the latter part of 1954, The Anaconda Company became interested in the district and decided to make a geological study of this new and promising base rrietal area. The following paper presents the story of the application of modern geological and geophysical techniques, leading to the discovery of a large sul-nhidp liodv. The Bathurst district is generally underlain by the Tetagouche group of Middle Ordovician rocks.

Jan 1, 1961

By AIME AIME

R. A. Hadfield, W. H. Bleckly, The Rt. Hon. Sir James Kitson, Bart., M. P.', E. Windsor Richards, E. P. Martin, Andrew Carnegie, Sir Hugh Bell, Bart., Bennett H. Brough. Patrons. Adamson, Joseph, & Co., Hyde; Aird, John, & Co., London ; .Akrill, C., & Co., Ltd., West Bromwich ; Anderson Foundry Co., Ltd.,. Port Clarence, Middlesbrough ;. Armstrong, Sir W. G., Whitworth & Co., Ltd., Newcastle-on Tyne ; As¬sociated Portland Cement Manufacturers (1900), Ltd., London; Babcock & Wilcox, Ltd., London; Baird, William, & Co., Ltd., Glasgow ; Baldwin's, Ltd., Stourport; Barclay, Andrew, Sons & Co., Ltd., Kilmarnock; Barrow Hematite Steel Co., Ltd., Barrow-in-Furness; Bayliss, Jones & Bayliss, Ltd., Wolverhampton ; Beardshaw, J., & Son, Ltd., Sheffield ; Bell Brothers, Ltd., Middlesbrough ; Bolckow, Vaughan & Co., Ltd., Middlesbrough ; Booth, Joseph, & Bros., Ltd., Leeds ; Briton Ferry Works, Ltd., Briton Ferry; Butlin, Thomas, & Co., Ltd., Wellingborough ; Butterley Co., Ltd., Alfreton ; Byrne, James, & Co., Middlesbrough; Cargo Fleet Iron Co., Ltd., Middlesbrough.;. Carnforth Hematite Iron Co., Ltd., Carnforth ; Cochrane & Co., Ltd., Middlesbrough ; Coltness Iron Co., Ltd., Glasgow ; Colville, David, & Sons, Ltd., Motherwell ; Consett Iron Co., Ltd., Consett ; Cooke, William, & Co., Ltd., Tinsley ; Craggs, R., & Sons, Ltd., Middlesbrough ; Darwen & Mostyn Iron Co., Ltd., Mostyn ; Dorman, Long & Co., Middlesbrough ; Dunlop, J., & Co., Ltd., Glasgow ; Ebbw Vale Steel, Iron & Coal Co., Ltd., Ebbw Vale ; Engineer, The, The Proprietors. of, Lon¬don ; Engineering, The Proprietors of, London ; Etna Iron & Steel Co., Mother¬well ; Farnley Iron Co., Ltd., Leeds ; Firth, Thomas, & Sons, Ltd., Sheffield ; Rather, W. T., Ltd., Sheffield ; Fraser & Chalmers, Ltd., Erith ; Frodingham Iron & Steel Co., Ltd., Doncaster; Gjers, Mills & Co., Ltd., Middlesbrough ; Glenboig Union Fire-Clay Co., Ltd., Glasgow ; Glengarnock Iron & Steel Co.; Ltd., Glengarnock ; Guest, Keen & Nettlefolds, Ltd., Birmingham ; Hadfield's Steel Foundry Co., Ltd., Sheffield ; Hall, J. & E., Ltd., Dartford ; Harkness, W.; & Sons; Ltd., Middlesbrough ; Harrison & Co., Ltd., Lincoln ; Head, Wrightson & Co., Ltd., Stockton-on-Tees ; Hill, John, & Co., Middlesbrough ; Hingley, N., & Sons, Ltd., Dudley ; Hopper, John I., Ltd., Thornaby-on-Tees; Hull Forge Iron &-Steel Co., Ltd., Hull; Iron and Coal Trades Review, The Proprietors of, London ; Ironmonger, The, The Proprietors of, London ; Jackman, Joseph, & Co., Ltd., Sheffield ; Jessop & Appleby Bros., Ltd., Leicester and London ; Jes-

Nov 1, 1906

By M. E. Wadsworth, T. D. Chatwin

The kinetics of sulfidization of hematite (Fe203) by H2S gas at various partial pressures have been determined over the temperature range of 170° to 500°C. The process was controlled by thin films of pyrite (FeS2) and troilite (FeS) which were protective and formed diffusional layers. At higher temperatures the thermodynamic drive to form FeS2 decreased, and consequently the rate of formation of FeS, decreased. Conditions for the development of thin layers of FeSz consisting of 10 to 100 atomic diameters are presented. Laboratory flotation results on synethetic ores indicate floatability identical to that of pyrite of normal xanthate flotation. The prospect of high-temperature sulfidization of metal oxides using H2S, S, or other sulfur bearing compounds is intriguing as a potential activation process for flotation since the thermodynamics are very favorable for a large number of systems. If the kinetic parameters are sufficiently well understood it may be possible to provide surface sulfide layers a few angstroms thick, thus imparting normal sulfide floatability characteristics to the oxide. For thin layers the total sulfur pick-up would be small except for very high surface area materials but in most cases this sulfur could be readily removed by roasting if necessary. The general reactions for the sul-fidization of metal oxide MxO, to a metal sulfide MpSq using H2S may be written for the three conditions py > xq; py < xq; and py = xq: A large thermodynamic advantage is obtained in many systems because of the relatively large negative free energy of formation of H,O compared to H,S. For the temperature range 2S° to 1500°C &apos; where AFOis the standard free energy and T is absolute temperature. As is evident from Eqs. 4 and 5, the free energy of formation of H ,0 is approximately 35 to 37 kilocalories per mole greater than that for H,S over broad variations of temperature. For oxide-sulfide systems as outlined above, sulfidization may be expected to occur for the conditions: Groups I and 111: that is, if the terms on the right are more negative than those on the left the reaction is expected to occur thermodynamically. The value hFg,(,) is included in Eq. 6 since hFLzs is based upon gaseous S2 rather than the normal reference state, orthorhombic sulfur. The

Jan 1, 1969

By J. H. Swisher

An experimental study has been made of the possible mechanisms for foam stability in the system CaO-SiO2-Cr2O3, where Cr2O3is the foaming agent. The degree of lowering of surface tension by Cr2O3 was determined at 1600 "C for high -silica melts. Measurements were also made of foam stability under standardized conditions. The results of the two sets of measurements then were correlated by applying the Gibbs and Marangoni theories of film elasticity. It was demonstrated that the Marangoni elasticity effect is probably the largest single contributor to foam stability, although the high uiscosity of&apos; silicate melts makes some contribution in controlling the rate of drainage of liquid from bubble lamellae. ThE tendency of metallurgical slags to foam has frequently been observed during steel-refining operations. In the open-hearth furnace,this tendency is considered undesirable because it slows down the rate of heat transfer from the burners to the molten-metal bath. On the other hand, it is sometimes desirable to have a "foamy" slag in the basic oxygen converter.&apos; A more effective blanket over the steel bath is made by a "foamy" slag, and loss in yield of metal due to splashing is minimized. In addition, a flush slag can be removed more easily in this condition. Since slag-foaming problems in the field have been attacked largely on an empirical basis, it appeared desirable to obtain a better basic understanding of the mechanism of foam stability. The experimental work was directed almost entirely toward the behavior of Cr2O3 as the foaming agent in CaO-SiO,-Cr2O3 melts. In the first stage of the investigation, the degree of lowering of surface tension by Cr2O3 was determined at 1600°C. The second stage consisted of measuring foam stabilities under standardized conditions. The two sets of experimental results then were correlated by applying various theories of foam stability. For convenience in interpreting the surface-tension and foam-stability results reported here, a portion of the CaO-SiO2-Cr2O3 phase diagram2 is reproduced in Fig. 1. EXPERIMENTAL 1) Surface-Tension Measurements. Very little information is available in the literature on the lowering of surface tension of slags by foaming agents. Kozakevitch 3 mentioned that the addition of 1.5 pct Cr2O3 lowered the surface tension of FeO slightly. In another system, some data on the lowering of surface tension of foaming slags by P2O5 were reported by Cooper and Kitchener.4 The technique used for the surface-tension measurements was the maximum bubble-pressure method,&apos; using a single tube immersed to various depths in the melt. This method has been used extensively in high-temperature systems, such as in liquid metals, slags, and glasses.6,7 It has the advantage that the contact angle between the liquid and the tube material need not be known. The equation used for calculating surface-tension values from maximum bubble-pressure measurements is the Schroedinger equatioq5 which can be written as follows:

Jan 1, 1964

Albin. B . R Billings. Mont . &apos;28 Amnter . Nathan L 26 Broad St.. New York . N . Y . &apos;28 Bache . Jules S 42 Broadway. New York. N . Y . &apos;28 Borrett . C . P . 5338 Harper Ave .. Chicago. I11 &apos;28 Baum . Frank G. . Cons . Hydro-Electric Engr Camel&apos;. Shasta Co. . Cal. &apos;23 Baylean, William S Russ Bldg .. San Francisco. Cal . &apos;28 Bean, Louis H .. V.P.. Dwight P . Robinson & Co.. lnc 126 E . 46th St New York. N . Y . &apos;28 Beatty . Roes J . 1106 First National Bank&apos; Bldg .. Chicago . Ill . &apos;28 Benwell . Oswald F . 110 Gilpin St .. Denver. 1310 . &apos;28 Beymer. Albert 9.. V.P .. Keystone. National Bank Pittsburgh. Pa . &apos;28

Jan 1, 1929