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By George E. Kruger, William F. Butler

The less developed nations maintaining a free enterprise economy (to which this chapter is addressed) have real and substantial opportunities to lay a foundation for general economic progress by using their mineral resources. Most of these nations have mineral resources which could be developed. By seizing these opportunities, nations seeking rapid economic development can secure a source of foreign exchange earnings to finance the imports needed for growth and, at the same time, increase the technical knowledge and well-being of an important part of their population. History clearly shows the manner in which most of the currently industrialized nations have used mineral resources to support their development. Indeed, few nations have managed to achieve a high level of income without a firm base of mineral resource development. The main exceptions appear to be the Netherlands, Switzerland, Denmark, and New Zealand, and the last two have based their prosperity on a highly efficient agriculture. Economic growth in the United States, the United Kingdom, Canada, France, Germany, and Russia was importantly based on the use of indigenous mineral resources. Despite this record of accomplishment through mineral development, many of the currently less developed nations are not taking advantage of the opportunities available in the mineral field. Restrictive laws or practices in many such nations operate effectively to prevent development of mineral resources. This failure to grasp real opportunities for development is based on a series of arguments that the mineral field offers few substantial and attainable advantages. Among these, the following propositions appear the most important:

Jan 1, 1964

FRIENDS of the late Charles F. Rand presented in 1930 a sum of money from which the income is available to support various phases of the work of the Institute in which Mr. Rand was so deeply interested. At present the fund amounts to $10,400. The specific terms of the deed of gift are as follows: "The fund collected to establish a memorial to the late Charles F. Rand shall be placed in the custody of the Board of Directors of the American Institute of Mining and Metallurgical Engineers, to be set up as a trust to be known as the `Charles F. Rand Foundation,' the income of which shall each year be applied to a distinct purpose to be decided upon in that year by vote of the Board of Directors. This purpose shall be such as to promote the general welfare of the Institute and to constitute a permanent memorial of the usefulness of Mr. Rand, who for many years gave unstintingly of his time and talents in its service. "It shall be within the discretion of the Board of Directors to establish a medal to be known as the Charles F. Rand Memorial Medal to be awarded at such a time and under such rules as may be determined by the Board of Directors, for Distinguished Achievement in Mining Administration." The establishment of this medal was announced at the annual meeting in February, 1932, the term "mining" being defined in its broad sense to include metallurgy and petroleum. Robert Linton is chairman of the Charles F. Rand Foundation Award Committee.

Jan 1, 1944

By D. B. Hobbs, H. O. Burrows, T. D. Stay

ALUMINUM which has lost its original identity as to source may be considered as secondary. This would include scrap originating in the fabrication of aluminum, which is not consumed at the plant of fabrication, and all material resulting from fabrication, which has lost its original identity regardless of whether it be consumed at the plant of fabrication or not. In general, secondary aluminum may be divided into two classes, commercially pure and alloyed. The chief impurities found in commercially pure aluminum are copper, iron, titanium and silicon; while in aluminum alloys, copper, iron, titanium, silicon, zinc, manganese, magnesium, nickel, or tin, may be present in varying proportions. Occasionally lead and antimony are found in secondary aluminum alloys, especially if the alloy results from remelting vender's automotive scrap. Such alloyed elements as are found in the scrap cannot be removed on remelting. In this, the remelting of secondary aluminum differs from the smelting of secondary copper or most other secondary metals. The majority of secondary materials reach the consumer in the form of remelt ingot or remelt No. 12 ingot. This ingot varies greatly in quality, depending upon the source of the material, and the manner in which it is refined and blended. The principal differences between primary and secondary ingot are: 1. The composition of secondary ingot may be more or less indefinite. 2. Secondary ingot may contain more dross and oxide. Secondary ingot may, however, be used successfully in a great many products. RELATION OF PRIMARY PRODUCTION TO SECONDARY PRODUCTION Table 1, compiled from data published by The American Metal Market, gives an approximate idea of the relation of primary to secondary production. Information obtained from other sources leads the authors to believe that the figures for secondary production are somewhat low.

Jan 1, 1928

By N. J. Grant, Masao Adachi

A number of Cu-SiO, and Cu-A1203 alloys of low oxide content, produced by internal oxidation of copper-silicon and copper-aluminum dilute solid solutions, were exposed at temperatures up to 1050°C for fairly long times to bring about partial or total re crystallization. The creep-rupture properties of these re crystallized alloys were compared to those in the as-extruded condition at 450° C. Some of the alloys were cold worked after re crystallization to note changes in creep-rupture properties, also at 450OC. SINCE the introduction of the SAP alloy in 1949,~ many studies have been carried out on similar oxide and intermetallic dispersion hardened alloys to determine properties and to establish the mechanisms involved in the strengthening process which led to stable, high-temperature behavior.'-' To date, it has been indicated that, however achieved, the structure should be composed of a continuous ductile metal matrix in which is dispersed a fine, submicron size, hard, insoluble second phase (or at least, essentially insoluble at temperatures very near the melting point), with a submicron or near submicron interparticle spacing. Stored energy, obtained by a high strain rate deformation process appears desirable, as an additional strengthening means beyond pure dispersion.=

Jan 1, 1961

EVERY dry thing that burns easily and multiplies or maintains fire by its own intrinsic nature can be put into an incendiary composition and various effects are produced. Some of these things are mineral combinations, like sulphur or its oil; some others, [163v] hot, dry, and subtle substances, like saltpeter; and some are. unctuous things, like fats and oils of any kind; while some serve because of dryness, like pith and wood. Some of these things are natural and some artificial But now I set aside the search for these differences in their composition. This is what I have found among all the ancient and modern things that I have been able to seek, and first, back in the time of Alexander the Great. Marcus Graecus, who was perhaps the inventor or a great experimenter and practicer of such things, writes of many of them. I have chosen some among these, and one* is this: In order to make it, he took Grecian pitch, alchitran, live sulphur, tartar, sarcocolla, niter, and petroleum oil, one part of each, and, in addition, a double amount of quicklime. He mixed it all with oil of egg yolks. Having put it in a well-covered and closed vessel of glass or glazed earthenware under warm manure, he left it for a month. Then, having liquefied it over a slow fire, always keeping the vessel well closed, he finally put this liquor in hollow sticks, in little pots, or in vessels expressly made, all with a little fuse fitted in the middle. If I should have to do this, I would say that a little gunpowder should be put in, which should give beginning to the fire so that it would ignite more easily. I have also found that another fire is made. For this sulphur is taken, or oil of sulphur if it is possible to obtain, petroleum oil or some rock oil, juniper oil, very well-refined saltpeter, and for one part of each of these five parts of asphalt; in addition, take goose or duck fat, pure black pitch, varnish, pulverized dove's dung, and enough aqua vitae to cover all the aforesaid things.. Then it is put in a glass vessel under warm manure for

Jan 1, 1942

By R. W. Bartlett

Hydrometallurgical processes for copper flotation concentrates avoid the SO2 emission problems associated with smelting, but they require oxidation of copper to obtain solubilization during leaching. The resulting copper ions must be reduced to metal, which normally requires large amounts of energy or energy equivalent reagents such as hydrogen or iron. The conventional reduction method is electrowinning which is labor intensive and involves 35 to 40% of both the entire operating and capital cost of the better hydrometallurgical processes. There is considerable incentive to reduce the cost and energy required for producing copper ions from solution. Furthermore, it is thermodynamically possible to do this using sulfur contained in the concentrate itself. In fact, the thermodynamic potential of oxidizing sulfur from S+4 to the S+6 state is greater than required to reduce cupric ion to metallic copper.1 Realization of this potential in a practical process would significantly reduce the cost of hydrometallurgical processing of sulfide concentrates because sulfur would become a cost-free reducing agent. An apparently practical method is to use SO: and HSO3 ions, obtained by ammonia scrubbing of SO2 from a concentrate roaster gas, to reduce leached copper to metal in an autoclave. This reduction step is the Jumau 1907 A series of steps, including sulfite reduction, constituting a crude flowsheet was suggested by Parker in 1976.3 The present paper describes a detailed complete. sulfite process flowsheet based on materials and energy balances, discusses the chemistry, and discusses further work that is required to develop this process. Process materials, utilities costs, and energy requirements are projected to be unusually low because of the utilization of sulfur from the concentrate. Process Description The sulfite reduction process requires a copper concentrate containing approximately as much sulfur on a weight basis as copper. For those few concentrates that are deficient in sulfur, additional sulfur can generally be obtained by allowing more pyrite to float in the concentration process. The process steps, shown in [Fig. 1], are (1) a fluid bed roast of the concentrate, (2) a leach of the roaster calcine using recycled barren liquor from the reduction autoclave, (3) scrubbing of the SO2 gas with ammonium sulfite liquor to produce ammonium bisulfite, (4) reduction and precipitation of copper in an autoclave by combining part of the SO2 scrubber effluent (SO5

Jan 1, 1980

By Charles Albert Ashburner

Natural gas has been known to exist for many years in the St. Lawrence Valley, between Quebec and Montreal, and more partirularly in the vicinity of Louisville and Three Rivers, 74 and 94 miles respectively northeast of Montreal, and 98 and 78 miles respectively southwest of Quebec; the distance from Montreal to Quebec along the St. Lawreuce River being about 175 miles. It was not until 1880 that any practical explorations were begun with the hope of finding gas in sufficient quantities for commercial uses. In this year Messrs. Piret and Genest, of Three Rivers, sank a well near St. Maurice to a depth of 50 feet, where solid rock was encountered. A similar well was drilled through the glacial and allavial drift, in the same district, in 1883, by the Messrs. Renaud Freres and Dubois, to a depth of 70 feet before solid rock was encountered. In this latter well a strong flow of gas was obtained. The gas was an outflow from a very limited reservoir in the porous glacial gravel, which had been filled from the gas resulting from the decomposition of vegetable remains, which had been buried in the gravel at the time of its deposition. Subsequently, other wells were sunk in the same way, with the hope of getting gas in commercial quantities from similar reservoirs. Commercial Gas.—By gas in commercial quantities I mean gas in such quantity that, if utilized with proper care and economy, it would generate steam at a cost below the cost at which the same duty could be obtained from the use of coal or wood at current prices, and that

Jan 1, 1890

By J. Jones-Parra

In previous Technical Notes, W. R. Rose' and W. Purcell have discussed the capillary pressure data presented by Welge.' Welge obtained capillary pressure curves of the imbibition type in which it was necessary to apply to the apparent wetting phase a greater pressure than that of the non-wetting phase to complete the cycle and reduce the non-wetting phase saturation to low values. Rose suggests in his Note that conditions of equilibrium could not have prevailed, since the. non-wetting phase pressure must always be the greater. Pur-cell in his Note, proceeds to postulate a pore system consisting. of a series of "holes in a doughnut," in which he contends that under equilibrium conditions it is necessary to resort to negative capillary pressures before significant wetting phase displacement can take place. There is a remarkable similarity between the shape of the capillary pressure curve calculated by Purcell and those measured by Welge. It is the purpose of this Note to show that, because Purcell neglected to account for the behavior of the residual wetting phase saturation, his system was not in equilibrium during imbibition; and, furthermore, that if his system had been in equilibrium, negative capillary pressures would not have been possible. In Purcell's pore system, the residual wetting phase will form pendular rings at the interstitial spaces existing somewhere within the system, for example, such as those spaces between "doughnuts" as shown in Fig. 1. The true capillary pressure is that across the pendular ring interface, and for the system to be in equilibrium the pressure drop across all interfaces must be the same, including that across the interface in the tight pores A of diaphragm B (Fig. 1). As the pressure across the cell is reduced, the advancing interface will move into the pore from the diaphragm, but at each pressure, the curvature of the pendular rings must be the same as that of the advancing interface if equilibrium is to prevail. Since equilibrium conditions are the basis for the entire argument, it follows that pendular rings must grow as wetting phase enters the pore, that is, as the pressure across the cell is lowered. In Purcell's calculated curve, the residual wetting phase saturation remains constant as the capillary pressure decreases. Thus, his curve does not represent an equilibrium process.

Jan 1, 1953

By Arthur L. Walker

In June, 1893, while I was with the Old Dominion Copper Co. at Globe, Ariz., I received an offer to take charge, as manager, of the Baltimore Electric? Refining Co. which had recently built a plant at Baltimore, Md., having a capacity of about 1200 tons of electrolytic copper per month, using the Hayden series system. This was a very large output, for in those days the plants were small and the art was in its infancy. At the beginning of 1893 there were 11 electrolytic refineries in the United States, most of them using the multiple system. The Hayden series system was used at Baltimore and Bridgeport and the Smith series system was in operation at the Electrolytic Copper Co. at Ansonia, COM., and at the Pennsylvania Salt Co. at Philadelphia. In the latter system the plates were placed in a horizontal position, but the operating difficulties were so numerous it was soon discarded. The total production of these 11 plants in 1892 was very small; I have not been able to discover reliable figures of production. There were about thirty electrolytic copper refineries in the world that year, according to Titus Ulke, and the entire production of these

Jan 1, 1932

By J. A. Herrick

Some time ago the writer needed a cheap, light, and portable hydraulic lift or crane, that would be universal in its application, and that might .be suspended from crane-arms, overhead tramways, beams, etc., and serve all the uses of ordinary hydraulic cranes. This was accomplished by the use of a closed cylinder of wroughtiron hydraulic pipe, provided at its top with the ordinary gland and stuffing-box, through the centre of which passed another similar pipe of slightly smaller diameter, forming in effect the ordinary plunger of the regular hydraulic crane. Over the top of this centre pipe or plunger or piston a disk of iron is placed with two arms projecting several inches from the rim, as may be required. Through these arms long iron rods pass, one on each side, and are fastened in place by nuts screwed to a bearing immediately above and below the disk. These rods also pass through the enlarged head of the lift down through a casting which closes the bottom of the cylinder, which, at the same time, gives them a bearing, and they terminate at a point below the casting equal to the height of the lift of the crane. The rods at this point pass through a disk similar to the top disk and are similarly secured in place. A common hook arranged with a swivel passes through the centre of the disk, and on this hook the load is suspended. For a stationary hanging crane the apparatus is suspended by two rods passing through the head of the lift in similar manner to the two already described, at right' angles to the first, and of sufficient length to let the first set play between them and rise to the full height which the plunger will allow. The second set of rods terminates in an iron disk similar to the one at the bottom of the first set, and a hook through this in turn suspends the entire apparatus. In order to adapt the lift to an overhead tramway, single or double, in place of the suspending rods, a projection or offset is arranged on each side of the head of the lift and a journal cast in, allowing the lift to be suspended on pivots arranged as follows:

Jan 1, 1879

By John Jermain Porter

The chief purpose of this paper is to indicate the laws governing the fuel-economy of the cupola, to examine the feasibility of some of the proposals for increasing its fuel-economy, and to show that the conditions limiting fuel-economy here are altogether different from those prevailing in the blast-furnace. The two methods available for studying the thermal efficiency of the cupola and determining the factors limiting fuel-economy are: 1, by the determination of the total heat-balance; and 2, by the application of the theory of critical temperatures. The case selected as an example represents a cupola operating under fairly efficient conditions. The data are as follows : Cupola, GO in. in diameter, 15 ft. high to the charging-door, with a 9-in. lining. Bed-charge, 2,000 lb. of coke and 4,000 lb. of iron. Subsequent charges, 400 lb. of coke and 4,000 Ib. of iron. Total number of charges, 20. There was 800 lb. of coke recovered from the drop, hence the total coke burned is 8,800 lb., or 0.11 lb. of coke per Ib. of iron. Coke contains 90 per cent. of fixed carbon and 2 per cent. of moisture. 300 1b. of kindling-wood is used in lighting. 80 lb. of limestone (95 per cent. of CaCO,) is used per charge, or 0.02 lb. per Ib. of iron. Melting-loss, 4 per cent.; distributed thus : Fe, 3.5; Si, 0.25; Mn, 0.25 per cent. Average analysis of top-gases : CO2, 15.1; CO, 10.0 per cent. Average temperature of top-gases, 1,600" F. Temperature of air and stock charged, 60" F. Dew-point of air, 50 F. The items entering into the total heat-balance and their calculation are as follows: 1. Heat of combustion of fuel.—Total heat evolved = 14,580 x lb. of carbon burned + 7,200 X Ib. of wood burned. Hence B.t.u. per lb. of iron charged =

Jan 1, 1913

By S. E. Bretherton

(San Francisco Meeting, September, 1915) DURING the year 1878-79, Anton Eilers, who was then interested in the lead smelting and refining business near Salt Lake City, Utah, made a somewhat radical departure from the regular practice at that time, which was to use but little lime in the slag, with a high percentage of iron. Lime was not only a cheaper flux than iron, but it enabled the metallurgist to make a more siliceous slag, an economical advantage in smelting where the smelting companies had to purchase either iron or lime to neutralize the excess silica, and penalize the ore shippers accordingly. The larger amount of both lime and silica in the slag also made it of lighter specific gravity, and a better separation of the metals and mattes was secured. This change in the formation of slags for lead smelting was brought about by Anton Eilers, prior to the Leadville mining excitement of 1879. We must also give Mr. Eilers credit for the general introduction of the hollow water-cooled cast-iron jacket for the blast furnace. Again referring to the use of more lime and less iron in the formation of slags,. there is no doubt but that it prevents the formation of a great many so-called "sows" in the lead crucible, such as were made in the early history of lead smelting in the Rocky Mountains; these sows consisted of lead, iron, arsenic, sulphur, copper, and other metals, including gold and silver, mixed with unconsumed fuel, and often, after vain attempts to cut them up or melt them to a suitable size for handling, were buried in the slag clumps to get them out of-sight. Another advantage derived from the adoption of high-lime slags. when smelting ore containing arsenic is the production of less speiss (a by-product heavier than matte, resulting from careless operation of the furnace, the lead being driven out of the crucible and sows built up). This speiss, while usually not as rich in precious metals as matte made at the same time, is too valuable to be thrown away; but it is difficult to treat, and it was thrown away or piled on the slag clumps in the pioneer clays of lead smelting in this country.

Jan 8, 1915

This story of the salting of a supposed diamond mine is a part of our Western history and deserves to be recorded in this book. It was more than a local affair, because it was concerned with persons in London and New York, as well as San Francisco. Part of the story has been told by Asbury Harpending in a little book published 12 years ago. Harpending (who died at New York in 1923) was in London in March, 1872, when he received a cable dispatch from William C. Ralston, the president of the Bank of California, stating that "a vast diamond field" had been discovered "in a remote section of the United States". Before starting for San Francisco, Harpending had an interview with Baron Rothschild, who showed a lively interest in the story, which was as follows: two weather-beaten prospectors went to the Bank of California and deposited some uncut diamonds and rubies for safe keeping; these precious stones were estimated to be worth $125,000. The men said that they had found the gems in "a desert portion of the West". They departed quietly, but the story was told in business circles; whereupon George D. Roberts, a mining engineer of wide experience and an associate of Ralston, sought an interview with the prospectors. One of them proved to be a man that had been in the employ of Roberts. Both prospectors, named Slack and Arnold, appeared "coy and cautious"; they were "simpleminded fellows", and were "afraid to trust anyone with the momentous secret ". They refused to divulge the place of discovery and declined "to part with their rights", but later "they became more amenable to reason" and expressed willingness to sell a half interest to

Jan 1, 1932

By Lynn Howell

IN a previous articles we have described a technique for measuring the relative intensities of gamma rays from the radioactive elements occurring naturally in geological formations along the walls of a borehole. The apparatus consisted of two Geiger-Müller tubes mounted inside a pressure-tight chamber. Each counter tube was coupled separately to an amplifier and a frequency meter at the surface by means of a multiconductor cable upon Which the chamber was suspended. The output currents of the two frequency meters were recorded on a photographic paper as the chamber was moved in 'the hole. These traces showed remarkable correlation with the geologic formations, as evidenced by comparison with commercial electrical logs.' Owing to the penetrating power of the gamma rays, logs may be taken in both open and cased boreholes. The apparatus has recently been changed somewhat. One of the counter tubes has been removed and a stage of amplification has been added. inside the chamber, This arrangement seems to give a more favorable signal-to-noise ratio and satisfactory logs can be now made in cased holes and also in open holes as previously, Briefly described, the chamber moving in the hole is made of 3,2-in. drill pipe and is about 10 ft. long. There is an additional extension about 2 ft, long at the top, inside which cable connections are made. The Geiger-Müller tube is mounted inside the bottom end of the chamber, Above this is the vacuum-tube amplifier with its batteries and transformer, In the top part of the chamber, small 45-volt batteries are mounted, which in part supply the high voltage for the counter tube, Additional voltage is supplied from the surface through the multiconductor cable upon which the chamber is suspended. Also, the output of the transformer in the single-stage amplifier is coupled to another single-stage amplifier at the surface through this cable. The surface amplifier is coupled to the Thyratron-controlled frequency meter, the tank circuit of which consists of a one megohm resistor across which is a bank of condensers varying in

Jan 1, 1939

By S. C. Geol, C. H. Page

INTRODUCTION Mining at Mindola Mine, Rokana Division of Nchanga Consolidated Copper Mines Limited is the deepest on the Zambian Copperbelt. Mining extends to 1150 metre depth so far and the present plans extend to 1500 metres, although reserves exist below this level. Mindola Mine is the major producer of copper/cobalt ore at Rokana Division and produces approximately 200,000 tonnes of copper/cobalt ore per month. A standard open stoping method is the only method used for mining with minor variations in positioning drilling drives and other development, figure 1. The standard main haulage interval is 75m but in flat dipping areas the full stope height is split into two or three panels. In 1970 severe mining problems were experienced when mining deeper than 850111 below surface. The main problems included: - Heavy support requirements in drilling drives near stope face. - Premature closure of blast holes necessitating pre-charging of the holes with explosives immediately after drilling and well before the day of blasting. - Severe bumping and spitting due to rock movements on drive surfaces and remotely within the rock mass under high stress. - Low mining efficiency due to dilution from the waste hangingwall. - These stress related factors also caused some premature detonations of precharged but unprimed blast holes which became a serious safety hazard. A number of alternatives have been considered to overcome these problems. A search for leas sensitive explosives to avoid the premature detonation problem has been partially successful, however, the need for a method of reducing stress levels at the mining face is still considered essential as the mine goes deeper. This paper describes experiments with Regional Support Pillars as a method of reducing stresses at the mining face.

Jan 1, 1981

By George W. Doffing

Numerous contradictory statements have been made in the past regarding the importance of the seasonal influence of demand for motor fuel on prices of oil securities. It has often been said that the time to buy oil securities is in the spring, or just prior to the heavy consuming season for gasoline. The fallacy of this argument is brought out in the following paragraphs. Seasonality of Oil-security Prices The indexes used in this paper as indicators of prices of oil securities and general industrials are those compiled by Standard Statistics Co. The oil producing and refining stock index includes 14 representative petroleum companies, while the all-industrials index is made up of 347 issues. All figures are stated as relatives, with 1926 = 100. The primary basis of the index, and one that gives a good weighting of the relative importance of the company within the industry, is the total market value of the stock issue outstanding; i.e., the market price times the number of shares outstanding. Adjustments are made for the addition or elimination of issues from the group index, for stock dividends, split-ups, stock rights, et cetera. At the present time the oil producing and refining index includes the following companies: Atlantic Refining Co., Consolidated Oil Corporation, Continental Oil Co., Gulf Oil Corporation, Humble Oil & Refining Co., Ohio Oil Co., Royal Dutch Co., Shell Union Oil Corporation, Socony-Vacuum Oil Co., Standard Oil Company of California, Standard Oil Co. (Indiana), Standard Oil Co. (New Jersey), Texas Corporation, Union Oil Company of California. In calculating the seasonal for oil-security prices several periods have been selected as indicat,ive of major changes in the industry, as follows: 1. 1918 through 1936. This gives an over-all picture of the industry during the motor-vehicle, motor-fuel era. 2. 1927 through 1936. This period includes the control stages, both voluntary and coercive. 3. 1927 to September, 1933. This is the pre-code period of control.

Jan 1, 1937

By W. N. Roberts

Hadfielcl steel has been studied by transmission electron microscopy to determine the microsl.rtic-ture of the cold-worked material, which has been a subject of controversy for many years. The presence of fcc deformation twins in specimens deformed in tension, by hamnzering, and by explosive -shock loading at room temperature lzas been established by electron diffraction. No evidence of a mar tensite was detected in any of the speciwens. Small amounts of E martensite were idenLified in the hamnleved specimens. DESPITE numerous researches on Hadfield steel since its discovery in 1882, there is still disagreement on the nature of transformations in the cold-worked material. Collette el al.,' using X-ray and electron diffraction, have found evidence for stacking faults, E martensite, and a martensite in Hadfield steel deformed in tension at room temperature. Nishiyama and Simizu,' using electron microscopy, have found stacking faults and E martensite in hammered Hadfield steel. White and Honeycombe have concluded from X-ray diffraction that Hadfield steel remains fully austenitic even after severe cold work at -196 Previous work by the author, indicating the presence of a, martensite in deformed Hadfield steel, was in error due to a faulty interpretation of the electron-diffraction patterns. Various workers,5'7 over the years, have speculated on the presence of deformation twins in Hadfield steel, largely from such circumstantial evidence as the persistence of slip bands with repeated polishing and etching, the presence of serrations in the stress-strain curve, and the absence of evidence of a martensite by X-ray measurements. The advent of electron-transmission microscopy and se- lected-area diffraction has made possible the positive identification of fine deformation twinning. PROCEDURE For tensile tests, standard ASTM specimens of 2-in. gage length, ground from 0.12-in. Hadfield steel sheet, were solution-treated at 1050°C for 30 min in a salt bath, to avoid decarburization, and water-quenched. The grain size was about 0.01 sq mm. Chemical analysis of the steel after heat

Jan 1, 1964

By Stewart Coleman, Thomas W. Moore, H. D. Wilde

It is recognized that in the early days of the petroleum industry oil was produced with practically no scientific or fundamental knowledge of the laws and principles governing its extraction from the ground. Only a few, if any, of those exploiting the oil resources made any effort to collect accurate scientific information. There was little need for it, for as is frequently the case where the supply of a natural resource appears inexhaustible and is greater than the demand, large profits were possible from merely skimming the surface with little regard to the efficiency or thoroughness with which the oil was obtained. With this policy in force, great quantities of gas were wasted and when the reservoirs ceased producing by natural means they still contained a large fraetion of the oil originally in them. The present tendency in the industry is toward conserving existing oil reserves. In order that greater percentages of the oil present in the ground may be recovered, efforts are being made to improve production methods and to rework depleted fields. If the production methods are to be improved intelligently it is essential that the fundamental laws be known and understood, consequently large amounts of money and effort are being spent in gathering data that will serve to define and interpret these laws. A great deal of attention is being focussed on the study of the motion of oil through an oil-bearing sand, the forces that cause it to move and the factors that affect its motion. It is recognized that one of the important factors is pressure, but its quantitative effect is not known. In a given field the rate of production declines with time and so does the rock pressure. Furthermore, a comparison of different fields shows, as a

Jan 1, 1930

By Harold Linke

THE following article presents notes and data compiled and computed by the writer for use in the determination of: size and slope of mill launders, details of junction boxes and downspouts, and distribution of pulp. It also includes pulp formulas, volume of discharge through bushings, paths of discharging streams, banking of turns and curves. In the design of a concentrating mill, the draftsman usually considers launders to the extent of providing ample "head" for transmission of pulp from one department of the mill to another. The superintendent of construction aims to build his launders wide and deep, and on a slope steep enough to ensure positive flow. So launders are laid generally on too steep a slope, with the result that the repair gang works to maintain launder bottoms and sides against the erosive action of the conveyed pulp. To this end many kinds of liners have been devised: concrete, mastic, white iron, glass, rubber. True, the reduction of slope to the point where a pulp will flow with minimum wear, will minimize labor and expense; but when the desired slope is not predetermined, the millman hesitates to readjust his launder slopes by cut-and-try methods. To the end that the desired size and slope may be found readily, the writer has: (1) conducted experiments with pulps of different specific gravity, screen analysis and dilution; (2) gathered a few graphic data from standard reference works (such as Peele's Mining Engineer's Hand-book and Taggart's Handbook of Ore Dressing); (3) computed several tables; and compiled results that have proved dependable for Utah Copper ore. It is quite possible that the following tables and graphs may not be applicable to all ores, but it is hoped that they may prove helpful, even in slight degree, in alleviating a portion of the trouble and migraine of some other millman.

Jan 1, 1939

By R. Simon

Maurer's review1 summarizes quite thoroughly the various theoretical developments and experimental findings that contribute to the knowledge of rock mechanics in drilling. This discussion supplements Maurer's paper by including generalities that either have been incompletely treated in his review, or formulated from new considerations by the discussant and from hitherto unpublished experimental data. These generalities are associated with the observation that all mechanical methods of rock drilling essentially comprise a sequence of indexed, concentrated loadings on the bottom of the hole being drilled. A concentrated loading is defined as a mechanical loading by a tool that contacts at any one time only a small fraction of the surface of the body being worked and penetrates only a small fraction of the body thickness. The surface in this application is the bottom of the hole. The deformation of ductile material by concentrated loading has received considerable attention because of the importance of indentation tests for measuring hardness of metals. Some of the generalities involved in concentrated loadings on ductile materials apply also to concentrated loadings on more brittle materials such as rock. Among these generalities is the applicability of similitude considerations to scaling laws and to force-displacement and energy-volume characteristics for tools of various shapes, as summarized by Tabor.2 Vork on the flow and fracture behaviors of glass loaded with pyramidal and spherical indenters is reviewed by Douglas.3 Maurer refers to the work of Evans and Murrell on wedge loadings on coal and on mixtures of pitch and sand. It is evident from Maurer's paper that a considerable portion of the studies of rock mechanics in drilling, such as crater formation experiments, has involved concentrated loadings on rock.

Jan 1, 1967