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By W. C. Winegard, W. J. Bratina

Internal friction characteristics and temperature dependence of the torsion modulus for iodide zirconium containing 2.4 pct Hf were investigated, using a low frequency pendulum technique. The internal friction curve consists of a background which increases as the temperature increases, a maximum at 860°C apparently a background due to the al-lotropic transformation, a maximum due to grain boundary relaxation with an associated heat of activation of 58,000 cal per mol, and an anomaly below 350°C which may be associated with a precipitation perphenomenon, Oxygen in below small amounts reduces the grain boundary maximum substantially. The variation of the torsion modulus at 20°C was found to be 3450 Kg per mm2 for the zirconium used in the present work. IT is well known that small amounts of certain solutes materially affect the ductility of zirconium. Lely and Hamburger,&apos; as early as 1914, found that high purity zirconium exhibited a remarkable ductility, while Fast&apos; has shown that oxygen and nitrogen can cause substantia1 embrittlement. Treco" has recently demonstrated that the ductility decreases sharply with the oxygen content, and that 2 atomic pct O2 embrittles zirconium to such an extent that cold working is impossible. The marked decrease in ductility is difficult to understand in view of the fact that Domagala and McPherson4 report the solid solubility of oxygen in zirconium to be 29 atomic pct at 500 °C. Another metal which behaves much the same as zirconium in this respect is titanium. Pratt et al." investigated the internal friction characteristics of titanium and the effect of oxygen on the internal friction values. It is evident that internal friction measurements are of value for studying grain boundary segregation, as shown by Pratt et al. for oxygen in titanium, by Pearson for oxygen in copper, and by Maringer and Schwope for oxygen in molybdenum. With this in view, the internal friction characteristics of zirconium and the qualitative effect of oxygen on the grain boundary relaxation phenomenon were investigated. Materials and Experimental Procedure The zirconium used in the present work was supplied by the Foote Mineral Co. in the form of wire 0.05 in. diam. The analysis supplied by the manufacturer indicates the amount of hafnium as 2.4 pct, less than 0.01 pct O less than 0.01 pct N,, less than 0.02 pct H,, and less than 0.001 pct C. Additional spectro-graphic analysis indicates the other main impurities as follows: 0.01 pct Fe, 0.05 pct Si, 0.008 pct Cu, <0.005 pct W, <0.001 pct Al, <0.05 pct Mg, <0.001 pct Ni, <0.02 pct Ca, and <0.01 pct Ti. Microscopic examination of the material in the as received condition revealed very fine grains with numerous twins. Specimens were annealed either in situ in the internal friction apparatus or in evacuated silica tubes in an auxiliary furnace. When the specimens were annealed in the auxiliary furnace, they were wrapped in identical zirconium wire to prevent contamination by the container. Metallographic sections were taken in all cases. Some were taken from the specimens used for internal friction measurements after completion of the experiments, while others were taken from control specimens at intermediate stages of the experiments. lnternal friction values were obtained by measuring the free decay of a low frequency torsion pendulum (1 cycle per sec), the suspension of which was

Jan 1, 1957

By David S. Bolin

INTRODUCTION This paper is directed toward those companies or individuals who may be considering the possibility of tin exploration or development projects in South America. Although tin deposits are known in many countries of Latin-America including Argentina, Peru, and Mexico, the majority of the deposits are located in Bolivia and Brazil. These two countries also account for virtually all the current production. Many factors affect the economic decisions related to mining and exploration projects in this region including the following: 1) Types of deposits 2) Anticipated size and grade of deposits 3) Deposit geometry and ore distribution as it affects the selection of a mining method 4) Metallurgical amenability 5) Governmental policies 6) Taxation 7) Anticipated capital and operating costs 8) Marketing costs This discussion will be directed toward each of these points. The majority of the presentation will be concentrated on Bolivia as this country is the principal producer in the region, however, the potential for further tin development in Brazil is excellent. Due to the remote and previously almost inaccessible location of the stanniferous districts of Brazil, little is known with respect to size and type of non-alluvial deposits which may exist in this vast country. TYPES OF DEPOSITS Two major types of deposits are currently being exploited in Bolivia; alluvial, and hard rock or lode deposits. Bolivia produces substantial tin from both types of deposit whereas virtually all Brazilian production to date has been from alluvial sources. Alluvial Deposits Brazil: The alluvial tin deposits of Brazil are located in river channels and flood plains adjacent to low mountain ranges. The terrain containing the tin placers is flat, marshy, and generally jungle covered. The major controls of alluvial cassiterite concentration are the ancient and present stream channels. The average tin concentration in the placers varies from 500 grams to approximately 1.0 kilograms per cubic meter. Tin reserves in the Rondonia field of Brazil have been estimated at 600,000 tons of fine tin. A bucketwheel suction dredge went into production in the Rondonia district in 1979, and four others have since been ordered. Several other gravel pump, and hand mining operations are also in production in this field. In addition to the Rondonia district, tin occurrences are known from Xingu, in Para state, and in the state of Minas Gerais. Bolivia: The alluvial deposits of Bolivia are somewhat more complex due to the variable geomorphology and abrupt topography. Conventional placer accumulations of cassiterite are found in many stream channels and intermontane basins surrounding the major lode tin producing regions. In addition to stream and valley placers, a group of deposits locally referred to as "Pallacos" or "Llamperas" which consist of colluvium, landslide debris and glacial moraine material, contain substantial tin reserves in some areas. The stream channel and intermontane basins contain the only deposits which are presently being exploited by mechanized methods. One dredge is working the stream channel below Cerro Rico de Potosi and another is operating in an intermontane basin southeast of the city of Oruro. Both of these dredges are operated by private companies. The average grade for these operations varies from 250 to 500 grams per cubic meter. The largest of the intermontane basin placers known at present is the Centenario deposit located adjacent to the Catavi lode deposit. This deposit contains approximately 170 million cubic meters of material with an average grade of about 150 grams per cubic meter. The "Pallacos" deposits are found on the slopes of mineralized areas and in glacial moraine. The mineralized material is generally completely unsorted, with tin and sometimes tungsten values distributed erratically throughout the entire mass. Most of these deposits are worked by small leasors or cooperatives; however, at least one mechanized washing plant is in operation southeast of Oruro. The size of these deposits may reach up to several million cubic yards. Grades are very erratic, but may range from 200 to 500 grams per cubic yard. In addition to the formal mining operations, virtually every drainage surrounding the major mines is being worked by independent&apos; miners utilizing hand mining and jig or pan concentration. The aggregate production from these operations is substantial. The

Jan 1, 1982

PAGE Problems of American Railroads Early in 1936, by J. J. Pelley 3 The Heavier Nonferrous Metals in Transportation, by C. H. Mathewson... 9 Light-weight Metals in the Transportation Industry, by Zay Jeffries 21 Trends in the Metallurgy of Low-alloy, High-yield-strength Structural Steels, by H. W. Gillett 40 Structural Steels and Light-weight Metals in the Transportation Industry, by Horace C. Knerr 62 Proposed Use of Alloys in Merchant Shipbuilding, by Edgar P. Trask 66 Mutual Effects of Metallurgy and Speed in the Automotive Industry, by Merrill C. Horine 84 The Railroads and Light-weight Equipment, by W. W. Colpitts 93

Jan 1, 1936

By M. D. Cooper

UNDERGRADUATES in mining engineering may be prepared for work by giving them sound instruction in the courses generally considered essential to the profession. The industry is not deeply concerned about the details of those courses. The average man in the coal industry does not wish to insist upon a rigid program. Therefore, he differs little from those in the teaching profession who evidently are not unanimous in their opinions, or all college catalogs would be alike. For the good of the profession, it is just as well that there should be differences in regard to details. It appears that students graduating in mining engineering from the accredited institutions receive similar instruction.

Jan 6, 1950

By Carl F. Lutz, Robert F. Mehl

A layer of brass was formed on 0 brass using a vapor-solid reaction technique. The variation in composition with distance within the phase layer and across the a -ß interface was determined by an electron probe. The diffusivities were calculated as a function of concentration; the diffusion coefficient in brass was found to change by a factor of twenty-five over a compositional range of 8 at. pct. An explanation is proposed to account for the large change in the diffusivity, based on possible stresses in the diffusion zone; it is suggested that the concentration dependence of the thermodynamic factor might decrease the activation energy with increasing zinc content. ALTHOUGH the body of data on diffusion coefficients (D- values) in terminal solid solutions and in isomorphous systems is quite large, there is but little quantitative information for intermediate alloy phases. This paper recounts measurements of D-values for the ? phase in the Cu-Zn system. The experimental method employed consists in the forming of alloy layers and determining and analyzing the concentration-distance (c-x) curve. The experimental method employed could have been applied to several systems; the Cu-Zn system was chosen because the D-values in the a and ß phases are well known, and can thus be used for purposes of comparison. The rates of growth, of intermediate alloy layers are known for a number of systems. In nearly all cases the thickness varies parabolically with time, as to be expected if the rate of growth is controlled by the D-values. In a few cases, nonparabolic behavior has been noted.1 Nonparabolic growth may be the result of a) a variation of the composition at the phase interface with time, b) interface-controlled kinetics, c) short diffusion times coupled with long vacancy lifetimes (in vacancy diffusion),2 and d) crystal reorientation during diffusion in anisotropic systems.3 In the Al-Ni system4 and in the Al-u5 system parabolic growth kinetics are slowly approached after an initial transient period. In general those phases stable at a given temperature in a system A-B appear as separate phase layers when A and B are put in contact and given a diffusion he at-treatment. In most cases the compositions at the interface of adjacent phase layers are those read from the phase diagrams for the termini of the respective phases. This discontinuity in concentration is taken as independent of time, and the growth of one phase at the expense of another is assumed to be independent of interface kinetics, i.e., the rate of interface movement is controlled by volume diffusion in the phases concerned. wagner6 has given many solutions for multi-phase diffusion processes, assuming that the chemical diffusion coefficient, D, is independent of concentration, as have others. Jost7 has pointed out that the familiar Boltzmann-Matano solution is as valid for a (c-x) curve exhibiting concentration discontinuities at phase boundaries as for the usual single-phase case. Heumann and associates8,9 have applied this solution to the multi-phase case, but lacking concentration data within the several layers were forced to assume linear concentration gradients, thus calculating only average D-values. The purposes of the present study were: 1) to determine the dependence of D on concentration, 2) to calculate the intrinsic diffusion coefficients D?Cu and D?Zn, 3) to establish the time-law for the movement of the interface, 4) to determine the concentration limits at the ß-? interface, and, 5) to attempt to clarify the mechanism of diffusion. EXPERIMENTAL PROCEDURE The ? phase is exceedingly brittle; conventional solid couples and conventional sectioning methods were thus inapplicable. Vapor-solid couples were accordingly employed. Unfortunately the equilibrium vapor pressures of Zn for the ? phase are unknown; to escape this awkwardness, samples were enclosed in a capsule containing powder of an alloy of known composition, sufficiently large in quantity as to be effectively an infinite source, maintaining the concentration of Zn at the sample surface constant with time. The sources of Zn-vapor which can be employed in reaction with Cu, or a brass, or ß brass, to form a layer of ? brass satisfactorily wide in concentration range, are alloys of the phases ?, or ? + E or ? + d (depending on the temperature).

Jan 1, 1962

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 F. M. F. Cazin

In my first paper, relating in general to the movement of solids in a medium, I stated a newly-discovered natural law, and explained its application to mechanical ore-concentration. This law, as applied primarily to the motion of ships in water, had been announced, demonstrated and defended by me in the Journal of the Franklin Institute for March, April and May, 1893, and has not been controverted since then. I therefore contented myself in my first paper with the simple statement of it; and in order to avoid unnecessary repetition, I refer the readers of this paper to that statement (ante, p. 81) and to the earlier publication already mentioned.*

Jan 1, 1895

By John R. Burger

Industrial mineral mines that have recently been opened, or soon will be opened in the northern circumpacific will produce potash in Canada, Mexico, and Thailand; phosphate in the US, Mexico, and Colombia; soda ash in the US; and chromite in the US and the Philippines.

Jan 1, 1982

By H. H. Murray

The largest reserves of palygorskite in the world are located in Anhui and Jiangsu Provinces in East Central China. The deposits are Middle Miocene in age and range from 3 to 6 m in thickness. The deposits are the alteration product of basaltic volcanic ash. The Chinese Geological Survey estimates the palygorskite reserves are in excess of 200 million tons. The elongate particle shape results in unique colloidal properties. Large quantities are exported to Japan, Taiwan, Southeast Asia, New Zealand, Australia, and West and Gulf Coasts of the United States. The markets include agricultural carriers, paint, joint tape compounds, animal feed binders, catalyst support, drilling muds, and suspending agents for chemicals, pharmaceuticals, and medicines. The viscosity is high and the quartz content is generally 5% or less.

Jan 1, 2009

By Calvin J. Konya

Many controversies and differences of opinion exist in blasting technology. The primer location in small diameter dynamite columns is an example of one of these controversial areas. It is generally agreed that in rotation firing of small diameter blastholes, primer placement near the bottom of the borehole is beneficial since it reduces the likelihood of cutoffs. The controversy results in the actual location of the primer in the bottom of the blasthole. Some references indicate that the primer cartridge should be the first cartridge in the bottom of the hole, with the cap pointed toward the collar of the hole. Others indicate that performance is improved with no sacrifice in safety by placing a tamped cartridge first in the hole, and the second cartridge being the primer. The following investigation provides some factual data for consideration.

Jan 1, 1980

By Brent Chamberlain

MARY KORPI: As has been typical today, our next speaker is filling in for one of his co-workers. Scott Lawson will be discussing "The Role of the Supervisor in Mining Operations" written by Brent Chamberlain of Independence Mining Corporation. Scott has more than 25 years in human resources management in the mining industry. He has worked in surface and underground mining environments in both precious and base metal mines. A graduate of Ohio University, Scott is currently manager of human resources at the Independence Mining Company&apos;s Cripple Creek and Victor Gold Mining operation located in Victor, Colorado. The only direction that I received from Scott was that he has to leave by 11:45 a.m. as he has a tee-off time with his boss at 1:00 p.m. Thank you to Scott for filling in today.

Jan 1, 1998

Earnings of engineers in the period 1956 to 1958 continued the upward trend observed in the previous survey interval, 1953 to 1956. The overall median (all graduates) was $6500 in 1953, $7750 in 1956 (a 19 pct upstep or about 6.5 pct annually), and $8750 in 1958 (up 13 pct from 1956 or 6.5 pct average yearly). The latter represents an increase from mid-1956 to mid-1958. For this same two-year span the Consumer Price Index rose 1.5 pct and the Average Gross Weekly Earnings for Production (Manufacturing) climbed close to 10 pct. Median earnings for the major classifications studied are presented in Table I. The increase in engineering earnings are not distributed equally among the various activity classifications or among the experience levels of the survey. Summary results of the changes of the median lines for the major divisions are presented in Table 11. Data in this table are approximations- dollars are rounded to the nearest $50 unit and percentages to the nearest full percentage.

Jan 1, 1959

HENRY M. Howe, Bedford Hills, N. Y (written discussion*).¬Mr. Foley&apos;s explanation of this interesting occurrence is perfectly reasonable. Possibly a word explaining the phenomenon more in detail may not be amiss. In the act of solidification each drop as it starts to solidify splits up into a half drop poorer in carbon and another half drop richer in carbon than the drop itself. The half drop poorer in carbon solidifies and attaches itself to-the already solid walls, whereas the half drop richer in carbon remains molten for the excellent reason that it is richer and hence is more fusible than the original drop, and hence in turn is wholly fusible at the existing temperature. Under usual conditions, as when the steel solidifies in a mold of any form, the successive molten half drops thus enriched in carbon remain present and by their enrichment progressively raise the carbon con-tent of the remaining molten mass, out of which successive half drops are continuously solidifying and attaching themselves to the already solid walls. Because the molten mass thus. becomes progressively richer

Jan 10, 1919

By Albert E. Long

Diamond-bit performance and cost data accumulated in core-drilling sandstones reveal significant trends of economic interest. Large-size, AA-Grade drill bort suffered less diamond loss per foot drilled than any other size or grade of diamonds assessed. Detailed analyses of the factors that affect diamond-bit performances -diamond size, diamond quality, bit size, bit type, percentage of core recovered, and physical characteristics of bit matrices -are assessed in the tables, graphs, and discussion. INTRODUCTION Since 1945 the Bureau of Mines has been compiling detailed performance records on diamond bits used in core drilling throughout the United States and Alaska. Analytical reports covering bit performance in various rocks are issued as in-formation on a significant number of bits used in anyone type of rock is accumulated. The first three such reports analyzed bit performance in gneiss,2/ schist,3/ and lime-stone and dolomite.4/ This report evaluates diamond-bit performance in sandstone. Data obtained from 627 bits, which drilled 42,665 feet on 45 different projects, are presented. The geographical distribution of the projects is shown in figure 1.

Jan 1, 1958

By I. Wigden

This paper discusses system integration and installation of High-Tec systems in underground mines. ABB has the capability to be a System Integrator and co-operates with partners in different areas of technology. Today it is difficult to find one Company that is responsible for the complete Automation System. The design of the system is also dependent on the caving procedure that is currently being used in mines. Most of the engineering must be done during the feasibility study and the design phase. Any mistakes made during these phases will be costly to rectify in the commissioning phase. The paper will also include a presentation of the benefit of using Automation in an Underground Mine, and the importance of integration with the people component. Most of the experience and discussions in this paper are from different technologies that have been developed in Scandinavia and adopted from LKAB in Kiruna. The author of this paper was responsible for the Automation projects in Kiruna Mine during1994 - 1999. These projects include: • Broadband communication of data, audio and compressed video in one data stream. • Control System for Haulage -1045m • Automation of Load Haulage and Dumping machines (LHD) • Control of Production Drilling Rigs from a Central Control Room.

Sep 1, 2001

By R. W. Baldwin

As used in geophysical exploration, the term overvoltage applies to secondary voltages set up by a current into the earth which decay when the current is interrupted. These secondary effects may be measured by pick-up electrodes. The term induced polarization has often been employed to describe this same phenomenon. In its own operations Newmont Exploration Ltd. commonly uses the word pulse. The basis of this method in prospecting is that metallic particles, sulfides in particular, give a high response, whereas barren rock, with certain exceptions, gives a low response. Overvoltage has been tried in searching for many types of mineral occurrence but has been most successful in outlining the widespread disseminated mineralization associated with porphyry coppers. History:&apos; Newmont Mining Corp. has been interested in overvoltage since 1946, when Radio Frequency Laboratories of Boonton, N. J.. drew the company&apos;s attention to phenomena observed in the laboratory. At the instigation of A. A. Brant further model studies were undertaken, and the first tests were performed in 1947. Tests at San Manuel, Ariz., in 1948 were very encouraging, clearly demonstrating that the method could be used to distinguish scattered sulfides at depth. H. 0. Seigel followed up the San Manuel work with a study to determine the phenomena involved.&apos;

Jan 1, 1960

By L. Dudley Stamp

The years 1935 and 1936 have been momentous ones in the history of oil exploitation in Burma. While the possibilities of the discovery of an important new field in the country have become increasingly remote, there have been surprising and to some extent unexpected developments in and near the old established fields. Further, these developments have not only an important bearing on the future of the industry in Burma, but they point to conclusions of, world-wide significance in connection with the disposition of oil pools. BC&apos;rma Independent of India According to the Government of India Act, passed by the British Parliament in 1935, Burma becomes independent of India, of which it was formerly a province. In future, therefore, statistics for Burma will be quoted separately from those of India. In 1934, 1935 and 1936 the oil production in India (including Burma) reached new high levels— though only a few per cent above the totals for 1919, 1920 or 1930. Part of the increase came from Assam, so that Burma&apos;s total is apparently below that of 1921. It must always be remembered, however, that Burma&apos;s largest potential producer—Singu—is used essentially by the Burmah Oil Co. as a reserve and its production is varied from year to year, and indeed from week to week, according to local market demand or the requirements of the Rangoon refinery. The figures of Table 1 must therefore be viewed in the light of these remarks.

Jan 1, 1937

This paper comprises a discussion of standards for comparing conditions in mines, of methods for measuring the flow of air, of a comparison of fan performances, and the application of these matters to mines in Western Australia.UNDERGROUND CONDITIONSIn approaching the question of mine ventilation one naturally searches for some standard by which to measure the conditions in a mine.There are several clauses in the Mines Regulation Act defining the conditions which are permitted. The quantity of CO2 is limited to 0&#183;25 by volume, but the estimation of CO2 involves a chemical determination and is not suited for general use in a mine.The maximum temperature is fixed at 87 0 F. (dry bulb), and at 80&#176; (wet bulb). The reading of temperature is easily done in the working places, and this is a very valuable and practical test of the conditions in a mine.The wet bulb temperature is probably the most important factor in determining working conditions. It is obvious that human life cannot be sustained for any appreciable period if the wet bulb temperature is above blood heat (about 97&#176;F.). In places where the wet bulb temperature is 90&#176;F. there is danger of heat stroke.In places where the air in a mine is still, the wet bulb temperature rises to a value close to the rock temperature.Adequate ventilation cools the workings by transference of heat from the rock to the air stream, and the temperature...

Jan 1, 1939

By R. V. Ramani, R. Bhaskar

An airborne dust cloud is an ensemble of particles of varied size, density, shape and states of aggregation. An understanding and quantifying of the dispersion and deposition of the dust generated in mines is essential to the development of measures for reducing worker exposure to dust. In coal mining, the major portion of the dust is generated during the cutting of coal using a shearer or a continuous miner. The major phenomenon affecting ambient concentration is the deposition of dust. Particle deposition may take place due to the effect of gravitational, inertial, electrostatic, and thermal forces, and mechanisms such as Brownian and eddy diffusion and inertial impaction. The three major mechanisms of deposition in turbulent flow in mines are diffusion (Brownian and eddy), sedimentation and inertial impaction. The mechanisms determining particle deposition are size dependent. From a review of the literature, there appears to be a knowledge gap in the understanding of the deposition phenomena in mine airways. In order to obtain a better understanding of the deposition of dust for various particle sizes, and to develop a set of data for evaluating predictive mathematical models for dust-flow in mines, a series of dust flow experiments was performed under controlled conditions in mine airways. It appears that the deposition data generally follow the theoretical behavior of dust based on the combined effect of diffusional and gravitational deposition. In this paper, the findings of the study on the deposition of dust in mine airways and its dependence on size, velocity and concentration are discussed. A set of deposition equations that could be used to determine the approximate deposition at various points in a mine airway are presented.

Jan 1, 1992

By Thomas Leonard Watson

Sulphide ore-bodies of more or less lenticular shape occurring in metamorphic crystalline schists, gneisses, and slates, and conforming closely in strike and usually in dip to the inclosing rock, have been recognized and described along the Atlantic seaboard from Quebec to Alabama. The ore-bodies do not entirely conform, in all cases, to the structure of the inclosing schists, but they sometimes cut across the foliation in dip, though conforming more closely with the direction of strike. In composition the principal sulphide mineral is usually py-rite or pyrrhotite, or both, accompanied by copper, frequently gold, and almost always some sphalerite and galenite. Other metallic ores are, so far as these sulphide bodies have been investigated, less common; silver is not uncommon, and in some of the pyrrhotite masses nickel is present in quantity sufficient to be commercially valuable. Cobalt frequently accompanies the nickel, usually in smaller amount, and the two vary much in relative proportion. Quartz and calcite are probably the most common of the non-metallic minerals. A number of silicate minerals are frequent representatives in one place or another ; garnet, am phi-bole, biotite, pyroxene, zoisite and others. The sulphide bodies of Virginia, comprising both pyrite and pyrrhotite, are among the most extensive along the Atlantic seaboard. Among the pyrite bodies may be mentioned the well-known and extensively worked mines of Louisa and Prince William counties, located on the main pyrite belt (A, Fig. 1) of the middle and northern, eastern Piedmont region in Virginia, and among the pyrrhotite bodics is the famous " Great Gossan Lead" (13, Fig. 1) of the Floyd-Carroll-Grayson coun-

Jan 1, 1908