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By Alfred V. de Forest

We are now assembled in this hall for the eighteenth lecture in honor of the memory of our greatest American metallurgist, Henry Marion Howe. Many of his most intimate contemporaries, led, as was fitting, by Professor Sauveur, have described his vital accomplishments in three fields: as a leader in technical industrial development; in theoretical research; and finally as a teacher and source of inspiration for nearly two generations of students. In 1914 Professor Howe had retired from active teaching, but maintained his laboratory at Columbia University under the care of Arthur G. Levy, with whom he published many of the papers that later were incorporated into his last book, " The Metallography of Steel and Cast Iron." My position at the time was that of personal assistant to Professor Campbell—no pay, no duties, but the great privilege of preparing specimens, taking pictures and attending to some of the current consulting work. Whenever possible, I visited Howe's laboratory to chat with Levy and gather ideas about the wonderful field of metallography—in which I was a rank amateur, rescued by the quiet enthusiasm of Donald Smith of Princeton from an instructorship in civil engineering. Levy let me act as a fly on the wall during the Professor's occasional visits. Busy as he was, Professor Howe took the time and trouble to encourage my interest, as he had done for hun- dreds of others. He told me how he went about gathering his own information speculating as to causes, considering experiments, and verifying his conclusions. I ventured to mention some tests I had run on the irregular stretching of wires of different metals. He read the small volume I had prepared of ill-assorted facts and fancies and remarked: "Nobody cares for your theories or the history of your tests. Describe what you found as briefly as possible and perhaps I can help you to publish." Curiously enough, among my discards were some autographically recorded load-versus-electrical-resistance measurements. Taken with inadequate knowledge and equipment, these curves did not reproduce consistently, but if the relationship between strain and resistance had then been explored, the latest type of strain gauge might have been in useful service for the past 25 years. Professor Howe was a gifted teacher, perhaps because he was primarily an ardent and assiduous student. His own eagerness to learn and his willingness to revise and extend his opinions constantly encouraged those of his environment to be diligent and painstaking in the pursuit of knowledge. In honoring his memory, I also wish to bring to mind the kindly, humorous and quiet Levy, and join his name again, as it was for too brief a space in the past, with that of many-sided Henry Marion Howe. Factors oF Impact Strength The subject chosen for the Howe Memorial Lecture by Dr. Gillett last year

Jan 1, 1941

A recent Evening Post Headline read 'Officialdoms Inertia Risking Millions in Growth Strategy'. The article beneath that headline outlined the difficulties encountered by the Government's growth strategy projects and included the paragraph 'public efforts by Government to brush up communication of the widespread nature of its growth strategy is believed to have been matched by efforts in private by some ministers to overcome their frustration at the constant delay while reports and paper work are moved between departments and through the system'. The article went on to point out that these delays could cost New Zealand millions of dollars in lost overseas exchange savings. We as responsible citizens should be appalled or at least concerned that such costly delays should or even could occur. But those on the outside of the system who spend much of their working life prodding, reminding, pleading, cajoling, even begging, the bureaucracy should be excused a smirk or a smile or even a good belly laugh. The Minister is usually a part of the bureaucracy passing judgment on someone else's proposals. This time the Government has plans of its own. Plans which it wishes to see implemented as rapidly as possible and even with the assistance of the precautionary National Development Act with its 'fast track' provisions those plans have got bogged down in the bureaucratic machine which this Government has done as much as any other to create. In the circumstances, the thought of Her Majesty's Ministers frustrated at the constant delay while reports and paper work are moved between departments and through the system is not unpleasing.

Jan 1, 1982

By R. J. Robbins, D. L. Anderson

A tunnel boring machine has potential use in al- most any type of mining where the access shaft (or adit) is large enough or can be made large enough for its initial entry and where the orebody is of sufficient size to warrant its use. Some time will inevitably be lost in negotiating curves or making lateral moves and moving from level to level. Nevertheless, if the orebody is sufficiently large, advance scheduling can minimize the lost time encountered in such moves. Ideally, a mine will be planned for the use of these machines, thus eliminating access and transport problems. From the viewpoint of time involved, the rate of advance by boring as compared to conventional means is worthy of review. For instance, the Blanco Tunnel, one section of the Bureau of Reclamation's San Juan-Chama Project in southern Colorado, was bored in competent sedimentary rock with the following performance:

Jan 7, 1967

By David H. Y. Tang, Syd S. Peng

In general, the strata sequence of the immediate roof in the under- ground coal mine openings can be divided into three types. They are: (A) each stratum deflects independently, (B) some stratum (or strata) loads on the underlying stratum, and (C) each stratum loads on its underlying stratum. The flexural behavior of the immediate roof which is made up of multiple strata not only depends on the material property, geometry, and external loading of rock strata, but also on the strata sequence. A computer program based on the beam-column theory is written for determining the bending stress and deflection for the generalized immediate roof. The flexural behavior of the immediate roof in various strata sequences are investigated for the following effects: roof span, horizontal stress, thickness and Young's modulus of the lowest stratum. In addition, some of the results are compared with the results of the finite element method.

Jan 1, 1983

By H. H. Smith, G. J. Danek, M. R. Achter

Nickel, Type 316 stainless steel, and copper show decreases in reversed bending fatigue strength with increases in air and oxygen pressure. The leveling off of the log N us log p curve for nickel at 300" and 816°C is discussed in terms of a model in which surface saturation gives rise to a critical pressure. A metallographic study indicated that the effect of environment on crack initiation and growth rates is a function of temperature. It is shown that small amounts of impurities in inert gases may substantially reduce the fatigue strength of nickel. 1n a previous investigation1 of high-temperature bending fatigue in air and in vacuum, reversals in the effect of environment with changes in test conditions were atrributed to a mechanism consisting of two processes acting in competition. One of them, oxidation strengthening, has been demonstrated in a straightforward manner by measuring the rupture strength of a sintered nickel-oxide bond.' The detailed operation of the other process, facilitation of crack propagation by surface absorption of oxygen, is uncertain. Thompson et UZ advanced the possibility that the formation of an oxide layer prevented rewelding of cracks during the compressive part of the cycle, while Wads worth and Hutchings4 further proposed that the reaction of oxygen with atoms at the tip of the crack helped the metal to break there, a possibility which has also been advanced to explain crack formation in creep.5 A difficulty in arriving at a mechanism for this lowering of fatigue strength in air is the inconsistency of some of the data. For example, Wadsworth and Hutchings4 found an approximately linear decrease of log cycles-to-fracture (N) with an increase of log pressure-of-air (p) for copper and aluminum at room temperature, while snowden,' although finding a similar linear dependence for aluminum, observed a stepped curve for lead. Between l0-' and 10"1 torr there is a sharp decrease in the fatigue life of lead with increasing air pressure, but plateaus, signifying no dependence on pressure, are found at higher and lower pressures. If, as discussed elsewhere: these environmental effects arise from the adsorption of gas on crack surfaces, it would be expected that as the pressure is increased a saturation point would be observed, beyond which there is no further effect. To gain further information about the form of the log N vs logp curve, it was decided in the present investigation to repeat this type of measurement at elevated temperature on nickel, copper, and Type 316 stainless steel. An additional object of this program was

Jan 1, 1963

By James Gibbs

In order to provide an initial approach to the deposits of oil shale, nahcolite, and dawsonite in the central area or the Piceance Creek Basin in northwestern Colorado, the U.S.B.M. and associated contractor personnel drilled and cased a 96-inch ID shaft to a depth of 2,371 feet. The shaft was constructed using ?big hole? drilling techniques and succeeded in giving access to previously inaccessible deposits of the above minerals. This report documents the construction from its beginning in January 1977 to its completion in January 1978. Procedures used and problems encountered are discussed in detail.

Jan 1, 1978

Jan 1, 1962

By R. W. O. Kersten

Backfilling is one of the options available to the mining engineer in mine design. The decision as to the type of backfill is dependent on the purpose for which it will be used. For example, in a situation where high-grade, steeply dipping multiple reefs are to be mined, the purpose would be the following: ? to facilitate maximum extraction; a ? to minimize loss of fines; ? to allow closely spaced multiple reefs to be mined; and a ? to create a working platform. The physical properties required which will satisfy the abovementioned requirements can then be defined; the design of the fill plant, as well as the transport of the fill, will be governed by these considerations. The same procedure is also adopted in deciding on backfill in single- reef gold mines. The first question to be asked is the purpose of the fill. It may be to reduce the energy release rate, for environmental reasons, to reduce timber usage, to improve productivity, to reduce stoping costs, to obtain higher mining extraction, and so on. Only after one, or a combination, of these factors has been selected, can the specifications for the fill be decided on, and the plant designed accordingly. The introduction of backfill at Sheba Gold Mine will be used to illustrate the procedure adopted by Anglovaal in determining the type of fill required.

Jan 1, 1988

By R Miller, D Hawcroft

The business environment is never still and there has been enormous change in demand, technology and opportunity during the last decade. In order to succeed it is necessary for organisations to change the way work is planned, scheduled and carried out. This is necessary just to survive over time. The success or failure of the business is strongly influenced by people; the way they work, the way they are guided and their feelings about being part of both a team, as well as an organisation. Our Sustainable Integrated Management System (SIMS) philosophy is built on the belief that people want to be constructive and creative and it is their environment and working relationships that influence how their energies are directed.

Jan 1, 2000

By J. Rourke, F. S. Minshall, E. G. Zukas, C. M. Fowler, O&apos

The Hugoniot curves were determined for Fe-Si alloys containing up to 7 wt pct (13 at. pct) Si. The pressure of the transition increased as the silicon content of the alloy increased. Single crystals of 2.9 wt pct Si-Fe were also studied. The pressure of the transition was not dependent on crystallo-graphic orientation. All of the Neumann bands (mechanical twins) were attributable to (112) planes but not all of the {112} planes showed twin markings. A thorough study of the iron Hugoniot (the relationship between specific volume and pressure) under plane wave shock loading revealed a pressure transition at about 130 kbar shock pressure. The results of this investigation were reported by Bancroft, Peterson, and inshall1 in 1956. At the time of this discovery, it was felt that this was probably the a, to y transition normally found in iron and many of its alloys. Subsequently a number of iron alloy systems were surveyed in which the alloying element has a considerable effect on the normal a, to y transformation. The influence of carbon and nickel and/or chromium have already been reported.2,3 At the present time, there appears to be some doubt that this pressure transition is the usual a, to y transition In this study, Fe-Si alloys containing up to 7 wt pct (13 at. pct) Si were chosen for several reasons. To the present, the transition has been found only in iron-base alloys which were originally in the a, phase (bcc). Secondly, the y loop at atmospheric pressure extends to only about 2.5 wt pct Si. If the transition were a, to y, then one might expect a rather drastic pressure effect for alloys containing more than 2.5 wt pct Si. Finally, single crystals of Fe-Si alloys large enough for shock loading studies are readily available thereby making it quite easy to determine the effect of crystal orientation on the transition pressure and on the twinning behavior of the alloy. EXPERIMENTAL PROCEDURE Fe-Si alloys containing up to 7 wt pct Si were produced by normal vacuum casting procedures. Single crystals of Fe-2.9 wt pct Si were purchased from Monocrystals Co., Cleveland, Ohio. The orientations of these crystals were determined and samples cut so that the shock wave would be parallel (to within 1.5 deg) to either the (loo), (Ill), or (112) principal orientations. Three distinct experimental testing techniques were used. First, the pin technique, described elsewhere,4 was used to determine the transition pressure for the polycrystalline alloys as well as for the (111) and (112) orientations of the 2.9 wt pct Si single crystals. Secondly, the recovery studies, described in detail in an earlier paper,2 were used for determining the effect of alloy composition and crystal orientation on the plastic II compression-plastic I rarefaction interaction zone for several specific shock pressures. Finally, measurements of pressures above the two-wave threshold were made on the polycrystalline alloys so that more complete Hugoniot curves could be constructed for this alloy system. The optical techniques described by Rice et al.5 were used to measure the shock and free surface velocities of the samples from which the Hugoniot data were obtained. This method is applicable only in the single wave region, since velocities are obtained from the measured total transit times of the disturbances through measured sample thicknesses.

Jan 1, 1963

By Gerald Sherman

In the southern field of the anthracite region of Pennsylvania, many of the coal seams dip at angles of 40" to 50" from the horizontal. For transportation purposes, "tunnels" are driven across the coal measures and, occasionally, "rock gangways," beside the seams and parallel with them. The use of gangways driven in country rock appears to be increasing, as they avoid the maintenance of long gangways in coal, which eventually are driven to the colliery boundaries, and permit mining from a number of intermediate blocks without interference. The rock consists of slates or sandstones of moderate hardness, which may range into very hard, highly siliceous, fine-grained conglomerates. In this distinctly bedded formation, the direction of the heading, whether parallel with or across the structure, makes it necessary to distribute the drill holes in a different pattern to break the ground, but does not change loading conditions. In 1932, practically all the mucking was done by hand, and it was the established custom to use four men on two drills for drilling and breaking the ground, and five for loading it out. A driver and mule was needed in addition, to assemble the rock cars at a siding or branching track in the rear, pending their final disposal. This might occupy the driver's whole time, or if the length of haul were short, he might be able to do other useful work. It was thought possible in 1932 to reduce the cost of driving such headings in rock by mechanical loading, and to investigate this subject a scraper loader was used in a section of tunnel then being driven. Operations while driving 195 ft. of this tunnel using a scraper loader were carefully observed. Time studies were made of the loading, and records made of the routine of breaking ground, but not in such detail. Tunnels or gangways in the colliery are 7 ft. high above the rails, by 10 ft. wide, which requires a minimum of 8 ft. in height, broken to allow for rails and ties. This cross section is of sufficient size to permit the use of any one of several types of power loaders, but for this demonstration it was found most convenient to use a scraper loader.

Jan 1, 1937

By J. D. Meakin, H. G. F. Wilsdorf

Using a combined decoration and etching technique the dislocation structure of annealed and deformed a brass has been studied. Annealed crystals revealed a low density forest and well-developed subboundaries; lightly deformed crystals contained discrete groups of dislocations. The dislocation density and the number of dislocations in a group were obtained from the micrographs. Using slip-line data, the mean path of a dislocation and the configuration of groups along an active slip plane have been deduced. Observations on secondary and cross-slip are reported. It has been the aim of many investigations to obtain detailed knowledge of the dislocation patterns which are present in metals before and after their deformation. The "decoration" of dislocations with impurity atoms has been considered as one of the promising experimental approaches, and much work has been done to develop this technique for revealing dislocation sites in metals. Following the early work by Castaing,' Castaing and Guinier,' and Lacombe and Berghezan~ on aluminum-rich aluminum-copper alloys, dislocations in this material have been studied extensively by others.+' In these alloys the dislocation sites act as nuclei for the precipitation of the second phase. The main results of the investigations on aluminum with copper are: i) the confirmation of the earlier contention that subboundaries consist of dislocation walls, ii) that many more dislocations are found in slip bands than in regions where less glide had taken place, iii) the observation of individual dislocations, lying nearly parallel to the surface investigated, and iv) that parts of dislocation loops, apparently emitted from a dislocation source, could be made visible. Recently, Jacquet, Weill, and Calvert have succeeded in revealing nearly concentric dislocation loops in quenched A1-4 pct Cu and thus indicated directly the existence of dislocation sources in a fcc metal specimen of normal dimensions. Another decoration method developed by Dash10'11 and applied to silicon crystals makes use of diffusing copper to the dislocations from a surface deposition. The dislocation pattern can then be observed by an infrared technique. His results include evidence for symmetrical and spiral Frank-Read sources, and for arrays of dislocation loops which follow simple crys-tallographic directions. Recently Low and Guard" have studied the dislocation structure of silicon-iron using carbon for the

Jan 1, 1961

The Use of Automated Mineralogy to Interpret the Batch Flotation Performance of Merensky Reef Ore

Sep 13, 2010

By M. H. Caron

BASIC U. S. Patent 1,487,145 on ammonia leaching of nickel ores was issued to the author on March 18, 1924. Equivalent patents in other countries were obtained later. The Dutch Syndicate Brikcarbo became interested in the process in 1935; and a couple of years later the late Dr. H. Foster Bain sent samples of Surigao laterite iron ore to Delft and witnessed tests made there on this material for the Philippines Commonwealth. As a result, the author was asked in April 1940 by Dr. Bain to go to the Philippines to erect and take charge of a pilot plant for the process. The World War prevented carrying out this proposal. The Dorr Co. also became interested in the process at about the same period. The investigations by the Freeport Sulphur Co. on the process as applied to the Cuban nickeliferous laterites, which resulted in the Nicaro enterprise, and the results of this operation have been well described elsewhere.1,²,³,4,5 This Nicaro plant was, in operation for almost two years, and during this period produced about 10 pct of the world nickel production from laterites containing 1.35 pct nickel. This plant and its operation were war measures and, in view of this, activities were suspended in April 1947. The results obtained fully demonstrated the technical feasibility of the process and its economical aspects on a commercial scale. In this respect, it should be understood that it is probable that improvements may be made by further development, and that there are possibilities for advantageous application of the process to garnierite and similar ores with higher values in nickel than the laterite iron ores at Nicaro. While the articles cited above have given a certain amount of information, no general article containing all the important process data has been pub- lished. Since the process is of more than local interest, a fuller knowledge of the fundamental and practical factors of the method may be welcome to those interested in this new field of metals technology. The author, accordingly, takes pleasure in submitting this article to the AIME as it represents in a condensed form the results of many years of research. The brief outlines of the fundamental and other factors and the explanation of observed phenomena are presented with as little discussion of details as possible, consistent with clarity. It is a special satisfaction to the author to make some contribution of his own in return for the benefits of the many valuable publications issued by the Institute during his thirty years of membership. Ores Adapted for Ammonia Leaching: All nickel and cobalt ores which originate from weathering of peridotites or similar basic rocks having sufficient values are suitable for treatment by the ammonia leaching process after a preliminary reduction under proper conditions. The formation of these deposits was probably as follows: In the course of time the basic rocks were attacked by atmospheric agencies; MgO and SiO2 were gradually leached out, and secondary nickel minerals formed, such as garnierite, a hydrated silicate of nickel and magnesia. These secondary products are, however, not stable. They decompose in a further stage of weathering and ultimately only a relatively small residue of insoluble oxides remains, known as laterite iron ore with a small nickel content and very little cobalt. Under these mantles of laterite, richer nickel values may be found, usually indicated by the occurrence of garnierite. The more the ore is disintegrated by nature, the higher the iron content and the better the nickel extractions that may be expected therefrom. Table I shows extractions that may be expected from different types of ores, assuming treatment of -200 mesh products and that all precautions have been taken for obtaining maximum extractions. As for the distribution of the various nickel minerals and compounds that may be present, great variations may occur from locality to locality as well as vertically in a deposit. From such "run of

Jan 1, 1951

By H. J. Sloman

Mining laws of the several coal-producing Stat e with respect to safety catches on mine cages and their testing are extremely variable and generally indefinite in scope. The most specific requirements are contained in the Coal Mining Laws of Washington,3/ as follows:

Jan 1, 1944

Although auriferous beach and fore-dune sands at Five Mile Beach south of Okarito township had been intensively mined by hand and primative mechanical methods drilling of the sandspit by the Gold Development Corporation in 1929 indicated that the grade and quantity of undisturbed black and grey sand below the water table was sufficient to support a mining operation. Worked sand above the water table also contained fair prospects. The Okarito Five Mile Beach Gold Dredging Co Ltd, was formed and an hydraulically powered, bucket ladder, sluice box dredge built. In 13 years of operation (1931 - 1943) the dredge returned 556.39 kg (17 890 oz) of gold at a recovered grade of 225.4 mg/m3. A total of ú42 000 was distributed as dividends on the ú30 000 capital investment. Recent drill and bulk sampling at the northern end of the beach has confirmed that reworking of the historic tailings by a modern gravity recovery plant would not be economic.

Jan 1, 1993

By D. E. Sherwood

Recent developments in high torque hydraulic rotary rigs has lead to the construction of secant bored pile walls by rotary drilling methods in circumstances where earlier methods were difficult and in some cases impossible. The evolution of secant bored pile wall construction is described including classical, rotary drilled and continuous flight auger construction methods. The paper then details the restraints which have been created in recent inner city redevelopment, many of which were not relevant in the early days of the technique. Typical examples of walls are presented to show the adapatability and advantages of the secant bored pile wall method. A number of in-situ retaining wall construction techniques are then compared in detail with regard to relative cost, technical quality and practicality.

Jan 1, 1989

By J. C. Zelanko

The U. S. Bureau of Mines conducted a multi-faceted geomechanics research project at a bump-prone longwall coal mine in eastern Kentucky. This mine presented a unique opportunity to study coal mine bumps in that the problem appeared to be confined to areas beneath a sandstone channel of limited areal extent. The Bureau's research plan sought to exploit the uniqueness of the site by monitoring strata behavior and longwall support reactions as the longwall face approached and passed beneath a sandstone channel. The study incorporated static pillar stress and strata deformation measurements, shield support leg pressure measurements, and microseismic monitoring as well as geologic mapping and the collection of observational data. Data collection was underway when a major coal bump occurred on the longwall face at the mine. Pillar behavior (load and deformation), shield loading, and microseismic activity were monitored prior to, during, and after the bump. Observations in the tailgate indicated that these pillars were failing prior to and after the face bump. Shield load data which were evaluated in an effort to identify trends which could be used to forecast coal bumps appear to provide a measure of the effectiveness of destressing operations conducted on the face (e.g. shot firing). Analyses of microseismic data revealed anomalous values associated with microseismic "energy" prior to the face bump. In addition, microseismic source location data and underground observations provided some insight as to the sequence of pillar and face bumps.

Jan 1, 1991

By Manuel Eissler

The material presented in this paper is an abstract of a thesis submitted by the writer to the faculty of the Massachusetts Institute of Technology, as part requirement for the degree of Master of Science. The investigation was undertaken at the suggestion of Prof. H. 0. Hofman, and it was conducted, under his direction, in the laboratories of the Mining Department of the Institute. The purpose of the work was, first, to study some of the reactions that have been considered as a part of the mechanism of the chloridiz-ing roast, and second, to study the conditions under which nickel oxide and copper oxide may be chloridized. While the production of chlorine gas by various reactions during the chloridizing roast may not be primarily useful in the chloridation of metal oxides and compounds, it nevertheless serves a useful purpose in preventing the dissociation and decomposition of chlorides once they have been formed; for example, the dissociation of cupric chloride into cuprous chloride and chlorine. Therefore it was thought that a study of some chlorine-producing reactions would prove of interest, and the first series of experiments dealt with this phase of the subject. he object of the latter part of the work was to show the possibility of treating heavy sulphide ores, such as those of Sudbury, Ontario, containing much iron and small amounts of copper and nickel, by chloridizing and removing the copper, leaving an iron-nickel oxide product suitable for smelting in the blast furnace for nickel-bearing pig iron. The chloridizing of the copper would, of course, be preceded by a roast for the removal of sulphur, the sulphur oxides being available for the manufacture of sulphuric acid, if under the local conditions this product would be of commercial value. Reactions of the Chloridizing Roast Reaction of Sodium Chloride, Sulphur Trioxide, and Oxygen.—The first reaction studied was that involving the production of chlorine

Jan 1, 1915

By Shadia Ikhmayies

Thermo-Calc software was used to investigate the phase diagram of the calcium silicon (Ca–Si) system for the range of Si mass percent 0–100, and temperature range T = 200–1800 K. The melting points of Ca and Si deduced from the phase diagram are very close to the values obtained experimentally. Three stable intermediate solid phases were found, which are Ca2Si, CaSi, and CaSi2, where the first one appeared in the Ca rich side of the phase diagram, and the third one in the Si rich side. In addition, three eutectic points were found at Si mass percents of 3.95, 33.00, 62, and temperatures T = 1048.7, 1519.14, 1308.5 K respectively. Atomic Si (Diamond structure) is found mixed with CaSi2 intermediate phase for temperatures less than 1305 K, and mixed with a liquid CaSi for higher temperatures. These results are important for thermodynamic and metallurgic studies of these intermediate phases.

Mar 1, 2018