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By H. C. Boynton, Albert Sauveur

In the course of some experiments conducted in the Metallographical Laboratory of Harvard University, some interesting facts were brought to light which appear to be worth recording in advance of a more elaborate and exhaustive paper which the authors hope to present to the Institute in the near future. Fig. 1 shows, under a magnification of 100 diameters, the microstructure of the cross-section of a steel bar 1/2-inch square, containing 0.52 per cent. carbon, heated to 1100 degrees C. and cooled slowly with the furnace. Fig. 2 illustrates the structure of the same steel, heated to the same temperature but cooled more rapidly in the air. Both samples were cut from the same bar and heated side by side in the furnace. When a temperature of 1100 degrees C. had been reached, one sample was taken out of the furnace and allowed to cool in the air, while the other was cooled with the furnace. The only difference, therefore, in the treatment of both samples will be found in their respective rate of cooling. This variation in the rate of cooling resulted, as shown

Jan 1, 1904

Jan 1, 1910

By W. A. Hoyer, G. A. Lock

Laboratory and field tests have shown that it is feasible to log for copper in a qualitative way using the techniques of neutron activation analysis. Laboratory tests showed that the 0.51 and 1.04 mev gamma rays of 62Cu and 66Cu, respectively, could be diagnostic. However, in the core holes, the detection of copper was limited to 0.3% concentration because of interferences from the 18Si and Al gamma rays. Both stationary and continuous logs were made, but only the stationary data yielded a recognizable copper response. This response consists of a combination of two effects-the direct response from copper at 0.51 mev and an increase in low energy gamma ray absorption due to mineralization. Both low energy chemical (PuBe) and high energy accelerator neutron sources were used for the laboratory and field tests, while the same 2 X 5 in. Nal scintillation detector served for all the tests. Potential improvements in copper detection might be possible with solid state gamma-ray detectors which have better gamma ray resolution but much less detection efficiency. This type of activation logging requires complex equipment and trained personnel to conduct field operations and may find application where coring is difficult or prohibitive.

Jan 1, 1973

By Arthur S. Coffinberry, Ralph Hultgren

We have studied the gold-aluminum system by X-ray diffraction and by the microscope over the entire range of composition for temperatures between 300° and 500° C. Results obtained are shown in Fig. 1, combined with the work of Heycock and Neville1 at higher temperatures. The diagram differs in important details from that given by Hansen2 in his critical compilation of the literature of binary alloy systems. This work was undertaken both because of the intrinsic value of a knowledge of the phase diagram of this system and because of the need of theoretical metallurgy for precise and accurate data, particularly X-ray diffraction data. Systematic studies of equilibrium diagrams, particularly by Hume-Rothery,3 have shown regularities that yield a certain insight into the nature of alloying forces. It has been shown, for example, that solid solubility depends on the concentration of free electrons in the alloy, on the relative radii of solvent and solute atoms, on the forces of attraction between atoms, and on the relative stability of intermediate phases. The well-known Hume-Rothery rule states that the crystal structures and compositions of many intermediate phases depend on the electron-to-atom ratio. This has been confirmed and extended by wave mechanical calculations.4 A knowledge of the forces between atoms in alloys, even an imperfectly developed empirical one, should be a valuable guide in the preparation of technological alloys of desirable properties. Furthermore, such information is basic in such problems as rate of diffusion, age-hardening, phase transformations, and others. The most valuable data for this purpose are furnished by X-ray diffraction studies. Unfortunately, work has been

Jan 1, 1938

By Arthur S. Coffinberry, Ralph Hultgren

We have studied the gold-aluminum system by X-ray diffraction and by the microscope over the entire range of composition for temperatures between 300° and 500° C. Results obtained are shown in Fig. 1, combined with the work of Heycock and Neville1 at higher temperatures. The diagram differs in important details from that given by Hansen2 in his critical compilation of the literature of binary alloy systems. This work was undertaken both because of the intrinsic value of a knowledge of the phase diagram of this system and because of the need of theoretical metallurgy for precise and accurate data, particularly X-ray diffraction data. Systematic studies of equilibrium diagrams, particularly by Hume-Rothery,3 have shown regularities that yield a certain insight into the nature of alloying forces. It has been shown, for example, that solid solubility depends on the concentration of free electrons in the alloy, on the relative radii of solvent and solute atoms, on the forces of attraction between atoms, and on the relative stability of intermediate phases. The well-known Hume-Rothery rule states that the crystal structures and compositions of many intermediate phases depend on the electron-to-atom ratio. This has been confirmed and extended by wave mechanical calculations.4 A knowledge of the forces between atoms in alloys, even an imperfectly developed empirical one, should be a valuable guide in the preparation of technological alloys of desirable properties. Furthermore, such information is basic in such problems as rate of diffusion, age-hardening, phase transformations, and others. The most valuable data for this purpose are furnished by X-ray diffraction studies. Unfortunately, work has been

Jan 1, 1938

By Bension Varon

Systematic projections of mineral supply, demand and prices are an integral part of the mineral sector planning process. As such, their primary value is not as prophecies but as devices for imposing discipline on thinking about the future and as means of ensuring consistency in policy decisions. Both the present and the broad outline of the future as presently discernable affect projections on specific minerals. The present world mineral situation reflects most prominantly the recent commodity cycle while our view of the future is largely shaped by perceptions and attitudes of policy-makers and the public over larger issues. Mineral commodities are of considerable importance to various countries. This in itself dictates a strong interest in systematic projection activities, the need for which is heightened by the volatility of certain basic variables affecting mineral demand in the world. It is useful for presentation purposes to discuss the various techniques suited for projecting mineral trends under three principal headings, viz., econometric modeling, systems analysis and technological forecasting. In addition, two specialized variants, input-output analysis and resource base modeling, are discussed. In each case, a brief description of the approach and some indication of its application to projections of mineral commodities are provided.

Jan 1, 1977

By S. Usui, I. Matsuoka, H. Sasaki, J. Shimoiizaka

Depression of galena by sulfite or chromate ion in xanthate flotation was investigated by means of adsorption measurements, electron diffraction and flotation tests. Flotation of galena was depressed by sulfite ion only when galena had been oxidized; no depression took place with unoxidized clean galena. A similar behavior was found when chromate ion was used as a depressant, with the exception that the chromate ion depressed unoxidized clean galena around neutral pH. Depression was attained with galena on which xanthate still remained in appreciable amounts, indicating that the depression is not due to a decrease in xanthate adsorption. The galena surface produced sparingly soluble films under conditions in which depression of galena took place. These films were identified by electron diffraction as lead sulfite and lead chromate on oxidized galena and as chromic oxide on unoxidized clean galena. These observations in conjunction with contact angle measurements, indicate that the depressing action of sulfite or chromate ion arises primarily from film deposition resulting from the reaction between depressants and the galena surface. The thickness of the film was analyzed by means of electrochemical polarization.

Jan 1, 1976

By Kenneth L. Clifford, Thomas G. White

Many changes have occurred in lead-zinc milling in the U.S. since the 1970 Lead and Zinc Symposium. New mills have been built, novel flowsheets devised, and the use of process control techniques is increasing. The Missouri concentrators produced in 1976 more lead and zinc concentrate than those in any other state. The Tennessee mills produced nearly as much zinc concentrate in 1976 as Missouri and with some very highly developed flowsheets. Progress in the Western U.S. is centered around new operations in Colorado and Utah. New mills in New York and Missouri incorporate many of the newer control concepts. Most of the older concentrators have undergone flowsheet changes to accomodate different ore types or because of the availability of new and better equipment.

Jan 1, 1977

By James E. Reynolds, Duane N. Goens, Charles W. Kenney

A process for recovery of lead and silver from high-grade lead sulfide concentrates by dry chlorination and fused salt electrolysis was developed by Hazen Research, Inc., for Cyprus Metallurgical Processes Corporation (Cymet). A pilot plant was designed to handle mixed sulfide concentrates and to produce high purity lead in a 2,000- ampere capacity fused salt cell. Design of the dry chlorinator and fused salt cell is discussed. Integration of modern chlorine caustic cells for reagent generation was evaluated in the pilot plant program. Also included in the paper will be process chemistry; pilot plant flowsheet, equipment and data: by-product and impurity removal: and scaleup and economic considerations for the process.

Jan 1, 1977

Jan 1, 1883

By R. F. Shurtz

This paper relates geostatistical doctrine to classical statistical and mathematical concepts. It is not a contribution to geostatistics; it is a contribution about geostatistics. It uses descriptive and pictorial arguments to assist interested readers in forming an intuitive grasp of the recondite and difficult mathematical issues involved. The method chosen is to cite authoritative literature references from the two fields and trace connections between them. Four broad conclusions appear: first, geostatistics comprises a relabelled subset of concepts detached from classical statistics and mathematics; second, this relabelling artificially isolates geostatistics from the classical fields and restricts its scope; third, the classical fields still have much to offer to the mining industry but will remain fallow unless artifcial communication barriers are removed; and fourth, the unique advantages asserted for geostatistics are neither unique nor necessarily real. These findings should not be regarded as iconoclastic but rather as Pointing the way to a wider and more productive scope for those who evaluate mineral deposits.

Jan 1, 1983

By José G. Aguilera

With the imperfect knowledge that me have of the geology .of the country in general, and of the numerous mining districts in particular, it is impossible to present an accurate idea of the geographical and geological distribution of the mineral deposits of the Mexican Republic. But, notwithstanding this, it is elear that the deposits are concentrated in limited regions of the country, and that certain deposits are so closely associated as to indicate, beyond doubt, a genetic relationship. The mineral deposits are numerous, and the most of them are found in the western part of the country in a zone following a SE.-NW. direction from Oaxaca to Sonora. In the eastern

Jan 1, 1902

Jan 5, 1950

By Edgar G. Hill

Much has been written and said recently about the methods used and materials and equipment employed in building the long tubes that criss-cross a great part of the United States, like the pattern of a spider's web. This paper will discuss the fundamentals of design of these lines from the economic as well as the engineering viewpoint, pointing out the effect of the volumes transported, and the load factor, on the unit costs of transportation, as well as the effects on costs of the character 01 the fluids the lines are called upon to handle. Generally speaking, crude-oil pipe lines carry oil from the producing fields to the refineries. Sometimes part of the journey is by pipe line to a coastal point and tank ships are employed for the rest of the trip. The main lines of directional flow of crude oil through pipe lines in the United States are shown on Fig. I, but this, of course, does not always show individual pipe lines. Basic Formula for Flow OF Crude Oil The laws governing the flow of crude oil through pipes are well known. The basic

Jan 1, 1942

By Edgar G. Hill

Much has been written and said recently about the methods used and materials and equipment employed in building the long tubes that criss-cross a great part of the United States, like the pattern of a spider's web. This paper will discuss the fundamentals of design of these lines from the economic as well as the engineering viewpoint, pointing out the effect of the volumes transported, and the load factor, on the unit costs of transportation, as well as the effects on costs of the character 01 the fluids the lines are called upon to handle. Generally speaking, crude-oil pipe lines carry oil from the producing fields to the refineries. Sometimes part of the journey is by pipe line to a coastal point and tank ships are employed for the rest of the trip. The main lines of directional flow of crude oil through pipe lines in the United States are shown on Fig. I, but this, of course, does not always show individual pipe lines. Basic Formula for Flow OF Crude Oil The laws governing the flow of crude oil through pipes are well known. The basic

Jan 1, 1942

By John A. Oberteuffer, James E. Lawver, Ionel Wechsler, Bo Arvidson

INTRODUCTION The demand for aluminum metal and thus for alumina and bauxite (the primary sources), is expected to increase at an annual rate of about 6% through the year 1980. It appears that about 90% of the future aluminum metal requirements could be produced at domestic plants but the production would remain dependent on the use of imported bauxite and alumina. The U.S. dependence on foreign bauxite and alumina is of considerable economic and strategic concern because availability and prices are very sensitive to changes in the political climate in the exporting countries. Dependence of the United States on foreign sources of bauxite closely parallels its dependence on foreign sources of oil, particularly since ten countries, including most of the world's major bauxite exporting countries, recently have formed the Inter- national Bauxite Association (IBA) for the specific purpose of increasing revenue for the participating countries. Although it is clear that long-term aluminum requirements cannot be fulfilled by domestic resources of bauxite,; the U.S. has an almost unlimited supply of aluminous resources such as Kaolinite (38% Al203), Alunite (37% Al203), Dawsonite (35% A1203), and Anorthosite (29% A1203)

Jan 1, 1976

By Z. T. Bieniawski

The efficient and safe design of room-and-pillar coal mines still remains as one of the pressing problems facing the mining industry in the United States. Present day design is a trial-and-error approach based mostly on experience. Although much research has been directed to stability of mine roofs and coal pillars, no generally-accepted design method has been formulated. This paper reports on a three-year research effort directed to an improved design of room-and-pillar coal mining in the U.S.A. Essentially the study consisted of three aspects: (i) determination of stable roof spans; (ii) determination of the strength of coal pillars; and (iii) determination of safety factors for room-and-pillar coal mining in the United States. Furthermore, three novel approaches were utilized during this research: i) the "petite sismique" technique was assessed for possible determination of coal pillar deformability ii) the "Geomechanics Classification" was extended for determination of safe roof spans in room-and-pillar coal mining. iii) a national survey of the current design practice and mining dimensions was performed with the aim of assessing factors of safety for room-and-pillar coal mining The outcome of this work, which is summarized in this paper, is a design code for room-and-pillar mining in the United States.

Jan 1, 1983

By Ronald D. Irving

The object of the present paper is to give an outline account of the mineral resources of the State of Wisconsin, so far as they are now known, including both metallic ores and non-metallic useful mineral substances. Tl~e only previous publication making ally attempt at such an account is one of a popular nature, prepared by the writer for Snyder and Van Vechten7s Historicccl Atlas of Wisconsin, which was published at Milwaukee in 1878. The data upon which the statements of the following pages are based are chiefly from the

Jan 1, 1880

By G. Lavagnino

The old Telegraph mine lies on both sides of Bear gulch, a short branch of Upper Bingham canon, and nearly in the center of the group of mines called the Bingham Mines, about twenty-seven miles southwest of Salt Lake City. It is considered, by local miners as the most important mine of the district. The geological formation consists of Weber quartzites, with subordinate conformable limestones and shales, alternating with porphyritic rocks. These widen towards and connect with the massive backbone of the Oquirrh mountains, while the quartzite develops itself on the slope broken through by Bingham canon. The porphyry not only runs between the strata, but also cuts across them, isolating large portions near the mountain mass, and again on a smaller scale it penetrates some joints in the quartzite. It is a crystalline felspathic rock, containing variable proportions of quartz, mica, hornblende, chlorite, and iron pyrites as accessories. In places, it takes a less distinct or almost uniform fine-grained structure. It has a gray or greenish, and, when much altered, also a reddish or even white color. The quartzite is a fine-grained or almost compact grayish-white or bluish or reddish quartz-rock, containing in places fine scales of mica and grains of iron pyrites as accessories. The raised, folded, or broken masses show well-defined bedding-joints, and their general dip is 35 to 50 degrees towards north or northwest. In the porphyry occur metalliferous veins with a prevailing N.E.S.W. strike. These are in general narrow veins; their principal contents are not dissimilar from those of the other deposits; but there is considerably less oxidation near the surface and the ore is mostly richer in silver and gold. In the quartzite the ore-deposits generally occur on the joints of bedding. The more important deposits occur either in clearlydefined contact-veins or, more often, in somewhat vaguely-defined mineralized zones, that could be called contact-zones. These comprise several masses of more or less altered or decomposed rocks and the newly-distributed products of their mechanical and chemical decomposition, such as breccia and clay in seams or in more irregular bodies..

Jan 1, 1888

By I. L. Greninger

THE property of the Andes Copper Mining Co. is in the central part of the Republic of Chile, Province of Atacama, 147 km. (91.5 miles) eastward by rail from the port of Chañaral. At this point the Andean system is made up of two principal ranges. The mine is on the westerly slope of the outer, or western, range, at a mean elevation of 3250 m. (10,500 ft.). A meter-gage railroad extends from the company's port at Barquito, near Chañaral, to the reduction plant at Potrerillos. This road has a total length of 151 km. (94.0 miles), of which 93 km. (57.79 miles) are owned by the Andes Copper Mining Co. The remainder of the road is owned by the state. The company operates its trains over the portion of the road owned by the state, under an agreement with the Chilean Government. The mine is connected with the reduction plant by a meter-gage railroad, 10 km. (6.214 miles) long, which extends from the coarse ore bins at the metallurgical plant to the underground storage bins at the mine. Tunnels make up 60 per cent. of the total length of this railroad. As is characteristic of the Andean region in Chile, the topography of the locality is extremely rough, and a number of points near the mine have elevations of from 15,000 to 16,000 feet.

Jan 1, 1928