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By ALFRED KAUFFMAN

NO matter what position we hold, workman, foreman, superintendent, manager, president, or what not, let us fail to give or to make good products, then see how quickly we'll be called to account for- our work by the buying public. The waves of progress taught us that millions were wasted in unnecessary strikes-we also learned that many losses were due to neglect on the part of manufacturers to give the same consideration and attention to the human element of their factory as they gave to their machinery. The employees learned also that the employer was their agent who found purchasers for the product of their labor. So between the two we learned that many years of labor were needed in order for a worker to recover his wasted savings, or for the manu¬facturer to replenish his loss. Treat 'em rough, and tell 'em nothing, was not very far from the true relationship between management and employees in manufacturing plants in the early days. Today just exactly the opposite views are held by executives whose function is the handling of employees. Men today want to know what it is all about. They are intelligent enough to comprehend the facts, and to use them constructively, and it is good business to give them the information.

Jan 1, 1929

By Allen Rogers

IT has always seemed to me that there is a certain similarity between the work of the mining engineer and that of the doctor of medicine-each has very often to be governed in his actions by conditions which he cannot. see. It is not necessary to detail the unseen conditions with which the mining engineer or geologist has to deal-the further extension of orebodies; the existence of new ones, the throw of a fault, the probable change in grade or character of the ore with advance of the workings, are a few of the conditions which the mining engineer has to determine as well as he can from the deductions he is able to make from what he can observe. Just so the physician is often confronted with conditions that he can not observe. Probably less than half of human ills make a manifestation at the surface of the body from which definite and certain conclusions can be drawn. The diagnostician must observe various things and, from these observations in combination, conclude what 'his course should be to bring about the cure of the trouble. Both professions would be assisted immensely by any agency that would permit them to look below the surface, something that would make more certain the diagnosis which each is called upon to make. The physician has had such an agency since 1895, when Röntgen discovered the X-ray; which, by making possible shadowgraphs of the osseous portion of the human body, advanced immensely the diagnosis of bone lesions. Later, with improvement in the technique and more understanding in the interpretation of what the photographic plate shows, other portions of the human anatomy could be examined and at the present time there is hardly an instance of internal disorder to which the aid of the X-ray is not called. Some organs are made opaque by administering mineral substances; in, other cases, conclusions are drawn from barely perceptible shadows on the photographic plate. Generally the surgeon's knife is directed with exactitude to the seat of the trouble and so not only is the difficulty revealed but the necessity for an exploratory' operation is averted.

Jan 1, 1928

By R. Neilson Clark

The discovery of a thin pay streak, yielding carbonates of copper; native silver, and perhaps chloride of silver, was made on the 9th of April, 1874, within the trachytic belt which forms part of the Sierra Mojada. The discoverer named it the Humboldt Mine. On the 2d of May, 1874, another discovery was made, in a northwest direction from the Humboldt, at about five hundred feet distant, this was named the Pocahontas Mine. After some exploration these two discoveries were proven to be on the same vein. To the southeast of the Humboldt a claim had already been taken up, called the Virginia; and to the northwest of the Pocahontas, one called the Southeast Leviathan. On these' last two this same vein has been found and worked. This paper will therefore treat of the Humboldt-Pocahontas vein, as worked on these four claims, to wit: beginning at the northwest, the Southeast Leviathan, the Pocahontas, the Humboldt, and the Virginia claims. Since the spring of 1874, there has been sunk on this vein a total of twenty-seven hundred and fourteen feet of

Jan 1, 1879

By R. Neilson Clark

THE discovery of a thin pay streak, yielding carbonates of copper, native silver, and perhaps chloride of silver, was made on the 9th of April, 1874, within the trachytic belt which forms part of the Sierra Mojada. The discoverer named it the Humboldt Mine. On the 2d of May, 1874, another discovery was made, in a northwest direction from the Humboldt, at about five hundred feet distant, this was named the Pocahontas Mine. After some exploration these two discoveries were proven to be on the same vein. To the southeast of the Humboldt a claim had already been taken up, called the Virginia; and to the northwest of the Pocahontas, one called the Southeast Leviathan. On these last two this same vein has been found and worked. This paper will therefore treat of the Humboldt-Pocahontas vein, as worked on these four claims, to wit: beginning at the northwest, the Southeast Leviathan, the Pocahontas, the Humboldt, and the Virginia claims. Since the spring of 1874, there has been sunk on this vein a total of twenty-seven hundred and fourteen feet of

Jan 1, 1879

By R. C. Gifkins

The ideas expressed in this paper interest me very greatly, partly for their own sake and partly because they are very close to some speculation I have recently made concerning grain boundary diffusion. This is in a paper describing an extension to Mott's "island" theory of the grain boundary, to be published shortly.37 The facets or islands of good fit are identified in terms of specific crystallography, as in the model put forward by Brandon et al., and the bad fit between them is suggested to be interlinked "channels" of relaxed vacancies, associated with grain boundary ledges.

Jan 1, 1969

By J. M. Morris

THE point to be made most clear in this paper is the economic value of flotation in the Benguet mill flow sheet. It is rather a statement of effect with no attempt at a technical explanation of the cause. Certain well-known, easily understood reagents, mechanisms and principles have been adapted to the conditions at Benguet, and have proved to be more successful than was demonstrated in the laboratory. The mechanical and metallurgical development of this particular operation was arrived at by trial and error, with fortunately very little error. Changes were slow, of necessity, which in the end proved a blessing in that time was afforded for observation and analysis of the disturbing factors; and as a result each change was a definite step towards higher efficiency. Many of these steps were unpredictable from labora-tory work because of the varied and differing characteristics of ores met with in daily operation of the mill, which were practically impossible to reproduce on a laboratory scale. The Benguet mill receives daily ores that differ as much as if they were delivered from three different properties. There is first the surface and upper-level zone, which produces an oxidized secondary ore contain-ing considerable iron oxide, manganese oxide and some organic matter. Formerly, most of this ore consisted of very soft fill with some hard rock mixed in. It also contained an unusual amount of iron and aluminum sulfate, which formed hydrates upon entering the alkaline cyanide solu-tion and caused excessive frothing. When flotation was introduced in the Benguet mill the general char-acteristics of this upper-level ore had changed considerably, in that it was practically all newly mined, fairly hard ore. It still contained many of the same disturbing elements, but was somewhat simpler to treat than formerly. The small proportion of fines is still troublesome in flotation, and plant practice probably does not show more than 80 per cent extraction on this small portion of the ore. No definite figure on this is available, as this particular ore is delivered at irregular intervals

Jan 1, 1936

By Frank M. Stephens, Robert D. Macdonald

As processes for handling low-grade or complex ores become more complicated and as new methods are found, the need arises for more complete and detailed pilot-plant studies to protect the capital investment required for a full-scale plant. Occasionally a process is firm technically, but there is a need for a demonstration plant that will convince nontechnical men of the wisdom of investing in a full-scale operation.

Jan 5, 1959

By W. A. Barrows

Mesabi ores differ from all other soft hematite-ores of the Lake Superior region in having but little or 110 binder. When exposed to heat, instead of baking into lumpy masses as do the Gogebic, Menominee or Marquette fine ores, they are changed to a sandy powder; and the finer particles, having little or no tendency to adhere together in the furnace, are carried by the ascending gas-currents into the down-comers and gas-mains forming flue-dust of a fine gritty nature. The term " finer particles " is used in this paper to mean ore fine enough to pass through a sieve with 80 meshes to the linear inch. Ore coarser than this is not likely to be carried over except in case of a slip, or an explosion in the furnace. The higher the percentage of fine particles in an ore from this range, therefore, the greater the amount of dust likely to result from its use. This statement, however, does not hold good in case of fine ores from the other ranges, and ores from the older ranges, carrying as high as 20 per cent. of material fine enough to pass through a 100-mesh sieve, have been in successful use for years, and have left no records of their causing trouble in furnace-practice by dust, slips, or explosions, so common since the introduction of Mesabi ores. Mesabi ores containing less than 12 per cent. of material which will pass through an 80-mesh sieve are considered of good structure; from 12 to 18 per cent., fair structure; and more than 18 per cent., poor structure. It was at first supposed that all these fine particles were carried over when the charge was lowered into the furnace, or during a slip, but the presence of partly reduced iron oxides in the flue-dust, even when no slip has occurred, proves that a part of the dust at least must have been low enough in the

Jan 1, 1905

By N. P. Weymont

A first step towards using advanced control and optimization techniques at Kaiser Aluminum's Baton Rouge Plant has been the decision to utilize digital process control equipment exclusively throughout the plant. This paper describes the philosophy and strategy which has been used to successfully implement this program for both existing plant facilities and plant expansions. Some of the problems that have been encountered include system selection, vendor support, soft- ware development, system security and system reliability. How these problems arose, were overcome and how they can be prevented in future projects is discussed. A key element of the success has been the organization of the technical, engineering and maintenance efforts and also training has been found to be extremely important. Finally, the effect of these experiences upon present thinking is discussed.

Jan 1, 1984

By Eugene Guccione

"All engineering societies should encourage and motivate their members to take part in public affairs. And engineers, in turn, should learn to translate their technical knowledge in a language which politicians can understand," stated James Boyd last month as he received the Hoover Medal, which is awarded annually by four engineering societies-AIME, IEEE, ASME, and ASCE-to an engineer who has rendered important public service. James Boyd is no ordinary engineer (see box). A few weeks ago, Dr. Boyd took time out of his busy schedule to stop at MINING ENGINEERING'S editorial office for the following exclusive interview.

Jan 1, 1976

By O. W. Walvoord

Mill design of the past will not necessarily dictate mill design of the future. There have been many advances and changes in the last few decades, many of which have been extensive and remarkable. Almost certainly, there will be still greater changes in the near future. Minerals beneficiation, for example, as it relates to future mill design, is likely to experience the greatest progress. Gravity separation, though one of the older arts, is in a continuous state of refinement. Flotation, having celebrated its 50th anniversary in 1961, has yet to be surpassed in its contribution to the art of mineral dressing. Ion-exchange, too, will flourish.

Jan 1, 1971

By L. Massé, Th. Koulomzine

Note on Haalck's Formula Quantitative interpretation of magnetic anomalies is admittedly a difficult process. Few authors have attempted a general approach to this problem. A number of publications can be found widely scattered through scientific periodicals, which present particular solutions obtained by the introduction of simplifying assumptions, such as the reduction to an equivalent magnet or pole, or the hypothesis of a very thin vein. The practical applications of these solutions are necessarily very restricted though they have given satisfactory results in isolated cases. Probably the most widely known equation of this type was given by Haalck.' His classic work contains curves calculated for typical conditions, and has now become a standard reference. However, a close scrutiny of Haalck's derivation reveals that, aside from the hypothesis of a thin vein, it rests on the

Jan 1, 1949

By GUY C. RIDDELL

ZINC, manganese, and aluminum received attention at the two nonferrous metallurgy sessions at the Annual Meeting. L.P. Davidson, general superintendent of the rebuilt Monsanto zinc plant, described its operation, which reflects Polish practice and is really a combination of electrolytic, Waelz, and retort procedure. Briefly, it embraces leaching of roasted concentrate with sulphuric acid, electrolysis of sulphate solution using Tainton lead-silver anodes with ?goulac? added to the electrolyte, treatment of tailing in Waelz kilns, and retorting of the recovered zinc oxide, casting furnace dross and residues. Recovery is good, equipment and maintenance costs low. Ferrate zinc that might be lost in the electrolytic process appears to be recovered as oxide in the Waelz treatment.

Jan 1, 1942

This is a brief account of the history of unit operation in the Salt Creek field, Wyoming, from the time of the agreement to prorate production in March, 1921, to the present. An attempt has been made to evaluate the savings in development and production costs resulting from the unit plans adopted. Summarized, these savings have amounted to $11,650,000. No effort has been made to estimate any increase in ultimate recovery, for it is believed that unit operation can be justified on saving in development and production costs alone. It would require nearly 20,000,000 barrels of additional oil to be produced in order to return the amount saved by not drilling unnecessary wells. Four horizons are affected by unit or near-unit programs, as follows: The principal operator is under contract with six companies to operate 10,400 acres. This includes all of the productive area of the First Wall

Jan 1, 1930

By R. J. Lutton

Basic features occurring on tensile fracture surfaces in rock are hackle marks, steps, and rib marks. Rib marks define the leading edge of the fracture and indicate that it was free of irregularities. In turn, fractures characterized by these features are believed to have propagated elastically and to be truly brittle. On the other hand, most fractures in rock exhibit hackle marks and steps in a plumose arrangement, indicating a ductile fracture process. Accordingly, the edge of the fracture apparently advances by extending en echelon fingers, each of which is in turn a small plumose fracture. Plastic-like deformation takes place in this zone prior to complete rupture. Some of the propagation is directed sideways and some shearing also occurs in this direction. Such lateral movement contributes little to forward propagation and may make this process particularly sensitive to load rate and duration and help account for greater fracture strengths of materials under dynamic loads.

Jan 1, 1971

By Gail Moulton

THE oilfields in Illinois are located principally along the LaSalle anti-cline in the southeastern part of the state. The oil produced comes most largely from beds of Pennsylvanian and Mississippian age, but there is an increasing important production from deeper horizons, as will be noted under new development. The oil is largely of paraffine base, and has an average specific gravity of about 35° Baume. The rank of Illinois as an oil producer has dropped from third since 1913, when its production was exceeded only by that of California and Oklahoma, to eighth in 1923. This has been the result of failure to find new pools of considerable size to offset the declining production of the old wells and of the greatly increased production of some of the other states. The noteworthy features of petroleum production in Illinois during 1924 are: the low rate of decline for the state as a whole; the smaller percentage of dry holes; and the larger average initial yield of the new wells.

Jan 3, 1925

By V. F. Marsters

THE main producing oilfields in Peru are located in the department of Piura and province of Thumbes, adjoining Ecuador on the south and west. In the department of Puno, a small field known as the Pirin or Hauncané Area was exploited some years ago by Fred Brown and associates and considerable production obtained. As. shown by the statistical table of production, this area reached its maximum production about 1909; since 1915, operations have been suspended. During the past year, however, the Peruvian Corpn. has acquired some interests in this section. It is reported to have made a few shallow tests with the hope of obtaining sufficient production to supply fuel for its railway lines, which operate between Mollendo on the coast and Puno and Cuzco in the interior. Only partial success has accompanied these efforts; nevertheless, exploitation is being continued. The petroleum of this region contains a paraffin base with small amounts of asphalt. While the gasoline content is small, the kerosene content runs as high as 30 per cent., with the fuel element varying from 50 to 72 per cent. While it is known that the structural conditions of the Huancané area are somewhat complicated, it is believed that exploitation based on a careful interpretation of the geology of the region will eventually yield commercial production of at least modest proportions. In the main fields in Piura and Tumbes, drilling operations were somewhat more active during the first half of the year, than in 1922. The latter half of the year witnessed curtailment, owing to the abnormal situation in the petroleum industry at that time. For the same reason, no attempt was made to obtain the maximum production from existing .wells. Production was pinched down and exportation of crude was correspondingly reduced during the latter half of 1923. Nevertheless, the total production of the Peruvian fields is considerably in excess of that for 1922, as is also the production of the Negritos area alone.

Jan 3, 1924

By William K. Antle

The successful application of ther mo compression lead bonding to semicondtctor or thin-film electronic devices depends on the establishment of the associated parameters. The quality of a thermocompression bond is primarily related to the process temperature and bonding force. A technique using the coelyicient of friction is presented that both reduces the time necessary for determining optimum parameter values and increases the accuracy of the results. Modern theories of the friction process are used to develop mathernatical expressions for shear and tensile bond strengths in terms of friction measurements. A further application of the pararneter-deterlnination technique concerns the measurement of surface contamination that may affect thermocompression bonding. In spite of the extensive use of thermocompression bonding, adequate methods for determining the bonding parameters have not been utilized. The quality of the weld depends on the temperature, force, and time used. There is a definite value or range of values for each parameter which assures an optimum weld. The process now generally used to obtain these values is to make several weld samples at each parametric setting, determine the mean pull strength, and relate the maximum consistent strength to optimum weld conditions. This could involve a very large number of test samples if a thorough search of each parameter were made. Experience and prior knowledge can reduce this number somewhat by limiting the investigation to a range known to contain the correct value, but the time and effort involved are still objectionable. The problems associated with thermocompression bonding of interconnecting leads to semiconductor or thin-film devices can be alleviated by the application of a new technique for establishing the process parameters. Obtaining the correct temperature, force, and duration to assure an optimum bond is accomplished by a simple measurement of the coefficient of friction. This approach increases the accuracy of parameter determination and greatly reduces the time necessary to complete the process. The approach made can be better understood by analyzing the principles of adhesion and friction on which thermocompression bonding depends. When two flat polished surfaces are placed together, the area of actual contact is much less than the apparent area determined by the over-all dimensions of the surface. This is because the microscopic surface is covered with projections which prevent uniform contact. Careful measurements of the electrical resistance across the contacting surfaces indicate the actual area may only be 1100,000 of the apparent area.' Because the actual contact area is small, extremely high pressure results from moderate force. This will produce deformation and plastic flow at contact points of the microscopic projections. The process will terminate in the creation of a large number of minute welds formed at extreme pressure and cold-worked to strong, hard bonds. Load removal will generally result in fracture of most of these microbonds because of the residual elastic stresses, unless the materials are soft. Friction between metals is due to the formation and

Jan 1, 1967

By Rana P. Singh

Electrolytic metal reduction operatios in both aqueous and molten salt electrolytes are being studied by digital signal analysis. The purpose is to determine the relationship between the physical processes occurring in the cell and the frequency spectrum of the cell's fluctuating electrical parameters. The fast Fourier transform of cell voltage (in galvanostatic operations) or cell current (in potentiostatic operations) is computed on-line in real time for the electrorefining of zinc in aqueous acid chloride solutions.

Jan 1, 1984

By A. E. Jenkins, A. Jostsons

Isothermal sections of the Ti-0-H phase diagvam at 600°, 700°, and 800°C have been constructed from equilibrium hydrogen pressure measurements over a range of Ti-0-H alloys containing up to 34 at. pct 0. Oxygen reduces the hydrogen solubility at fixed hydrogen pressure but increases the terminal solubility in the a solid solutions at the a/(a + P) phase boundary. Metal-lographic studies of alloys annealed below the eutectoid temperature show that oxygen also increases the ter-ninal solubility of hydrogen in the a solid solution in equilibrium with the hydride phase. The effect of oxygen on hydrogen solubility is discussed in terms of the electronic and geometric structure of interstitial solid solutions. THE isothermal solubility of hydrogen in a Ti-0 alloys at 800°C has been measured by Hepworth and ~chuhmann' who subsequently used ternary Gibbs-Duhem integrations to calculate oxygen activities in binary Ti-0 alloys. The present study aims to extend Hepworth and Schuhmann's measurements to alloys richer in oxygen and to a range of temperatures. This paper presents the results of hydrogen equilibrium pressure/concentration measurements in Ti-0 alloys as well as observations on the effect of oxygen on the terminal solubility of hydrogen in a titanium. The thermodynamic properties of binary Ti-0 alloys, derived from these measurements, will be published separately.' EXPERIMENTAL METHODS Specimen Preparation. Ti-0 alloys were prepared from iodide-refined titanium and titanium dioxide obtained by hydrolysis of redistilled titanium tetrachlo- ride. Specimens containing up to 16 at. pct 0 were prepared by electromagnetic levitation3 whereas a conventional tungsten arc furnace with a water-cooled copper hearth was used to melt oxygen-rich alloys. The specimen homogeneity was indicated by the constancy of lattice parameters of samples from various parts of the ingot as well as by the sharpness of the reflections on X-ray powder patterns. Oxygen-rich specimens in the composition range (20 to 34 at. pct), where ordering has been ~bserved,~ were annealed for 300 hr at 600°C prior to use in hydrogen solubility measurements. Apparatus. The hydrogen pressure/concentration measurements were made with a modified Sieverts apparatus shown diagrammatically in Fig. 1. Specimens were placed in a clear silica tube and impurity pickup by direct reaction with silica was prevented by lining the heated end of the silica tube with thin molybdenum sheet. A double silica tube was required to eliminate loss of hydrogen by diffusion through silica at high temperatures and high hydrogen pressures, the space between the tubes being maintained at a hydrogen pressure equal to that above the specimen. Hydrogen was purified by diffusion through a Ag-Pd tube.= Hydrogen pressures were measured with a mercury McLeod gage in the range 0.001 to 4 Torr

Jan 1, 1968