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By Henry Rawdon

Cold-working is generally considered as a process of hardening metals. Diamet-rically opposite statements concerning the applicability of the scratch-hardness method in the testing of cold-worked metals, particularly after severe deformation, which exist in the technical literature led to the study of the results which are summarized in this paper. A series of metals, of which copper, iron and tin are used as illustrations here, were cold rolled to a definite degree without any intermediate annealing and the hardness determined by both the scratch and Brinell methods. The results indicate that the metal hardens rapidly during the initial stages of deformation; however, after a certain stage, which corresponds to a rather definite microstructure, the metal becomes softer and in its final form may be softer than the metal in its initial stage. As part of the study of the scratch-hardness method for metals and alloys in cooperation with one of the technical committees of the American Society for Testing Materials, the authors devoted considerable time to the study of the changes in hardness of metals when cold rolled. Various seemingly contradictory statements in the technical literature concerning the applicability of the scratch-hardness method to such cold-rolled materials were among the principal reasons for the investigation, the results of which are in part presented here. The effect of cold deformation, at least in moderate degrees, on the hardness as measured by the Brinell and other common methods is so well known that further reference is unnecessary. Concerning the scratch hardness of cold-worked metals, Martens and Heyn state' that hardness, whether measured by the ball-pressure method (Kugeldruck) or by the scratch method (Ritzverfahren), will be increased by cold deformation. Jeffries and Archer give a seemingly diametrically opposite view. They state,2 that "the sclerometer (indicating scratch

Jan 1, 1924

By H. B. Smith, B. Egererg

In a previous paper1 the authors dealt with the physical properties of cold-rolled and heat-treated Britannia metal of the approximate composition Sn, 91 per cent., Sb, 7 per cent. and Cu, 2 per cent. It was found that cold rolling to more than 50 per cent. reduction produced a continuous softening of the metal when measured by the Brinell machine, whereas the Shore instrument indicated increased hardness; that the strength of the material followed the Brinell hardness and that the metal therefore became weaker the more it was cold-rolled; and further, it was found that hardness and strength could be largely restored to the cold-rolled metal by "baking" for about one hour at any temperature between 200" and 450" F., the melting point. The higher the baking temperature, the more effective was the heat treatment as far as increased hardness was concerned. It seemed to be of little importance whether the metal was soaked or not at the baking temperature for a great length of time and the rate of cooling seemed to be immaterial. The present paper deals with the same alloy and more particularly with the resistance towards various forms of stress — tensile, bend and deep drawing. The metallography of Britannia metal has in part also been covered and an explanation attempted for the abnormal behavior of this alloy. Tensile and Bend Tests Two ingots 73/4 in. wide, 11 in. long and ¾ in. thick were cast from the same pot. One ingot was cold-rolled in one direction to a strip 0.241 in. thick, which furnished the tensile test specimens; the other ingot was rolled in the same way to 0.253 in. and furnished the specimens for the bend tests. The ingots were cast as described in the previous paper and cold-rolled in six passes.

Jan 1, 1930

By W. E. Gaby

SINce the time of their discovery, the genesis of the ores at Mount Morgan, and the nature of the changes which have affected the surrounding rocks, have been the subject of investigation and speculation by geologists and mining engineers. Developments at this mine, for a long period the greatest gold producer of the world, show that with depth the orebody grades into copper, of which metal it now furnishes a large output, exceeding in value the gold. In earlier times, the purity of the gold and the first extremely heterogeneous character of the ore made it an interesting problem. Now, the probable depth of the copper enrichment, genesis, and true relations of the neighboring rocks furnish equally profitable material for investigation, and the present somewhat detailed description of these ores and rocks, from microscopic study, may prove of interest. , The mine occupies a highly silicified portion of a belt of quartz-porphyry, which is believed to be the oldest rock of the region. This belt of quartz-porphyry and allied rocks runs north and south between two areas of a later intrusive granite, as shown on the geologic map,' Fig. 1. Near the orebody the quartz-porphyry has been intruded by a dense basaltic mass called the " Old Basic." Cutting all three of these igneous masses are two sets of basaltic dikes, one running northwest-southeast, and the other, cross dikes, northeast-southwest. These dikes may be contemporaneous with, instead of later than, the ore. Their number has caused peculiar difficulties in extracting it, as the clay selvage of decomposed material affords no adhesion between dike and ore, causing great blocks to loosen and come down. The investigation was based on specimens furnished by B. Magnus, former general manager of the mine, and notes on the areal geology by

Jan 1, 1917

By Ellis Clark

These mines were discovered by George W. Lufkin in August, 1878, and mere worked almost continuously until August, 1893, a period of fifteen years. The ore-deposits in this locality lie close to the surface, and it is strange that the Spaniards, passing and repassing for nearly three centuries, did not discover them, particularly as they are marked in several places by large outcrops of black flint and iron, which would lead even a casual observer in a mineral country to suspect the proximity of ore. The mines are situated about six miles from the old Santa Fé trail, and fifteen miles from the Rio Grande. The geology is such that a skilled geologist passing over the ground would probably suspect, from the peculiar arrangement of the formations, the occurrence of ore. The formations in the district, eruptive and sedimentary, are nine in number; and of these eight are to be found within one thousand feet of the Grande workings. Topography. The topography of the Lake Valley district shows its dependence on the surface and underground geology, in a degree more marked

Jan 1, 1895

A filled stope is one in which the support for walls and men and, at times, for the back of ore, is furnished by waste rock or sand tailings. The filling may be rock sorted out in the stope or from the walls, develop-ent, or the surface. The orebody is mined in sections, each practically an open or timbered stope, filled wholly or in part before adjacent ground is attacked. As a rule, the filled-stope method is limited to overhand flat-back, stepped-face, or rill stopes. The examples given are Copper Range, Iron Cap, Verde district, Zaruma district, Lucky Tiger, and Silver King Coalition.

Jan 1, 1925

By H. C. Jennison

Two distinct types of defects occur at times in copper wire as a result of the use of dies of improper design or undesirable wire-drawing practice. The conditions under which these defects may be produced, as well as precautions to be taken in order to prevent them, have been known to The American Brass Co. for many years. The quality of the copper wire bars and rods has too often and unjustly been held responsible for these particular defects and it is to correct any such belief that this paper is presented. An extremely high quality of electrolytic copper has been supplied to the trade by all refineries for the last 20 years at least. The purity of the copper would average well above 99.900 per cent. The casting of the wire bars has been handled in a generally satisfactory manner. The bars have been cast sound, with a flat to slightly crowning set and have been free from sloppy edges, cold sets, etc. In other words, the wire bars have met A. S. T. M. specifications and have been generally satisfactory. For the most part, they have been everything that could be desired from a quality standpoint yet most of the wire mills in this country and in Europe have at times held the quality of the copper responsible for the two types of defects described in this paper. As a matter of fact, these defects are produced entirely in the wire mills. The author has visited many of the large wire mills in the United States and in Europe to investigate these defects. In some cases the trouble has been so serious that the wire mill has ceased operations. At times the wire mills are reluctant to believe that they are responsible for the defective product. The effect of die design, wire-drawing practice, etc., upon the quality of copper wire has received little study on the part of wire mills, particularly those that have commenced operations in the last few years. Two Types of Defects One type of defect is generally known in this country as "check marks;" in Europe it is termed "crowfeet" (Fig. 1). This defect occurs in the surface of the copper wire, in the form of V's, which are always

Jan 1, 1930

By Delbert E. Gann, Richard D. Hagni

Ore microscopic study of copper-bearing shale at the Creta mine in southwestern Oklahoma reveals a variety of copper sulfide grains and shows that each has originated by replacement of original constituents In the Permian Flowerpot Shale at Creta. The largest grains, about 120 pm in diameter, are replacements of megaspores with triletes morphology. Their interiors are shown by Auger microprobe analyses to be organic matter. The interior organic matter and the spore exines have been replaced by anilite and djurleite. Digenite and anilite replace collomorphic pyrite averaging 40 pm in diameter. Grains 10 pm or less in d~ameter are mostly euhedral, six-sided, platy crystals that have anllite compositions and are pseudomorphous after pyrrhotzte. Other 10 pm copper sulfide grains are pseudomorphous after octahedra and cubes of pyrite. The results of this study indicate that the copper minerals are epigenetic and were deposited from fluids introduced into the Creta shale when it was relatively uncompacted and permeable. The shale served as a favorable reducing environment that contained a source of sulfur in the form of pyrite and pyrrhotite.

Jan 1, 1985

By Carl F. Dietz, Dyke V. Keedy

The problem of drying ores is one that most mill-engvineers are sooner or later called upon to meet, and it may be timely to point out some of the difficulties resulting from such operations from purely a metallurgical and economic standpoint. We mean, in the following pages, to discuss primarily the effect of such operations on the ore. itself, without particular reference to the mechanical or cost features of the subject. That an appreciable tonnage of the ore fed to the usual form of drier, either rotary or stack, is lost, is fairly well appreciated, but we believe that only a few mill-managers know just what their drier-losses amouilt to, and we have found that in most cases they console themselves with the fact that the drier-smoke is not very much discolored, and it is generally believed that the draft is not sufficient to carry away more than a negligible percentage of the values.

Jan 1, 1913

By Gregory M. Dexter

Recent litigation in Pennsylvania between three coal-mining companies and a private water company resulted in the payment by the coal companies of the equivalent of about $500,000 to buy a new water supply to replace that which had been damaged by acid drainage from strip mining. An investigation of the relevant facts indicates that the water could have been treated by spending about $40,000 on equipment and $15,000 yearly for chemicals, labor, and power until the contarnination could be reduced about 80 pct. The water company's supply, furthermore, had deteriorated largely by reason of dry weather before stripping was begun by the coal companies. Payment to the water company should not have exceeded $300,000 and could have been as low as $100,000. Strip mining of coal is common in Pennsylvania. The most important objection to it in Pennsylvania is generally acid pollution of runoff water. An outline of the methods, therefore, that could be used to reduce such pollution, to compare acid-contaminated waters. and to treat such waters to make them satisfactory for public and industrial use is worth-while. The watershed of the West Penn Water Co. covers about 4.5 square miles, 20 miles west of Pittsburgh, and has two 90,000,000 gal reservoirs supplying about 1,300,000 gal daily for public and industrial use of which 450,000 gal daily are for two railroads. The pollution arises from weathered derivatives of typical'" Coal Measures"' rocks, the principal source being pyrite (and marcasite) in Pittsburgh and Rooster coals. Springs and seeps on hillsides issue from sandstone and limestone formations intersecting shale or clay land surfaces, or from perched water tables. The two reservoirs create an artificial permanent water table. Soap-hardness tests on three seepage samples taken in a dry summer ranged from 150 to 500 ppm. Water sampled came from aquifers above Pittsburgh and Rooster coals, obviating the possibility of contact with pyrite-containing coal. Since acid contamination of mine waters is the result of chemical reactions of oxygen and water with pyrite, it will be reduced by the exclusion of either air or water. The Sunnyhill Coal Co. has applied this principle in its "contouring" method of strip mining by burying contaminated coal-waste material under a compact, smoothed-up surface of top-soil, gravel, clay, and sand at a cost

Jan 1, 1950

By H. E. Mussey

When the American Institute of Mining Engineers visited the Birmingham district in May, 1888, the four Ensley furnaces (Fig. 1) then completed were referred to as monumental.' Their dimensions are givcn in Table 1. Mr. Gordon stated, with considerable satisfaction, that on the preceding day one furnace had produced 165 tons. The blast was

Jan 1, 1925

By Maurice K. Seguin

It is a difficult task to find enriched soft iron ore deposits in the central part of the Labrador Trough, New Quebec, Canada, when the areas investigated are covered by glacial drift. A qualitative interpretation of either a combined gravity-magnetic-seismic-resistivity survey or gravity-magnetic-seismic or gravity-magnetic-resistivity survey permits (with a low probability level) the detection of iron formations and ore zones as well as their delineation from most of the country rocks. This is possible because most of the altered iron formation underwent a slight increase in density through enrichment and because the accompanying geochemical alteration changed their magnetic properties. In order to increase the chances of success in finding ore bodies when using geophysical methods, different types of correlation were done for many deposits. These are: I) A quantitative correlation of the residual gravity anomaly intensities with the specific gravity, the iron content, the silica content, the porosity factor, and the dimensions of the underlying ore bodies. 2) A quantitative correlation of the ground magnetic intensity relative to a reference lithologic unit with the percentage of Fe.,O, recovery and with the volume ferromagnetic susceptibility. A few discoveries already have been made with this method. The details of the location, the description of the geology, and the history of previous geophysical surveys and their qualitative interpretation have already been given.', ' A very brief paragraph describing the regional and local geology is necessary in order to facilitate the understanding of this paper. The sedimentary iron formations of the Labrador Trough consist of a 700-mile geosynclinal segment composed of tightly folded and faulted Proterozoic sediments, volcanics, and intrusives that are rich in mineral deposits. The complex sequence rests unconformably on the basement of Archean granitic gneisses. The direct-shipping iron deposits are scattered along a northwest-trending strip, 5 to 10 miles wide and some 60 miles long in the facies rich in iron oxides and preferentially in localities where the original sedimentary environment favorized the deposition of a large concentration of magnetite associated with chert by physicochemical processes, e.g., oxidation-reduction potential, pH, temperature, pressure. Once leached of its silica and/or iron carbonate content and enriched with secondary a-hematite (occasionally goethite), this original magnetite associated with some primary hematite makes the blue direct-shipping ore which constitutes the important ore reserves in this mining district.

Jan 1, 1971

By Zay Jeffries

Jan 1, 1930

By Robert U. King, John W. Vanderwilt

THE Climax molybdenite deposit in Lake County 100 miles southwest of Denver is located in the central part of the mineral belt extending northeasterly across the state. Principal geographic features and geology are shown on Fig. 1. The first period of molybdenite mining, which began in 1918, ended in April 1919 because of limited demand and a price drop to about 72¢ per lb. During this time the ore came from the Leal level and surface outcrops at a higher elevation. Rate of mining was 250 tpd and several million tons of ore averaging 0.7 pct molybdenite were developed. Since April 1924, when the second period* began, Climax Molybdenum Co. has been the only operating company. Production in 1924 was 400 tpd and finding ore was a continual problem. When the White tunnel was extended, however, further ore was encountered. The orebody was thought to be tabular until 1926, when B. S. Butler recognized the relation of the developed ore on the Leal and White levels to a central area of fine-grained hydrother-mal quartz, and by 1929 diamond drilling had blocked out indicated ore reserves in excess of 100 million tons. In 1946, on the basis of information obtained from 25 miles of mine workings and a completed exploratory program involving over 200,000 ft of diamond drilling, the present authors reviewed and brought up to date the geology of the orebody. More recently Sears," employing microscopic techniques, made a study of hydrothermal alteration and mineralization, and Howell and Schassberger'" restudied available geologic data. Production (1953) of molybdenite ore has been expanded to over 25,000 tpd and total production from 1918 through 1953 has been: Tungsten, tin, and pyrite are byproducts and monazite also was produced from 1949 through 1951, after which it was not saved. A maximum of 15 to 20 tons of monazite was produced. Geology of the Area Pre-Cambrian crystalline rocks constitute most of the Mosquito Range for several miles to the north, east, and south of the Climax molybdenite deposit, see Fig. 1. To the west the crystalline rocks are in fault contact with shales and sandstones of Pennsyl-vanian age. Both crystalline rocks and sediments are intruded by dikes and sills of Tertiary age. Numerous faults with small displacements are to be found in the crystalline rocks east of the Mosquito fault and in the sedimentary beds to the west. Pre-Cambrian Rocks: The pre-Cambrian rocks consist of schist and gneiss, identified with the Idaho Springs formation, and granite with minor pegmatite correlated with the Silver Plume granite of the Silver Plume area. The Idaho Springs formation is a general term applied to pre-Cambrian schist and gneiss found over a large part of the Colorado Front Range. At Climax this formation consists largely of biotite-schist and quartz-biotite gneiss with minor quantities of plagioclase and orthoclase, although in places appreciable quantities of feldspar and quartz are present in the more gneissic varieties. Locally, especially along the contact with granite, recrystal-lization of the schist has produced coarser texture and a more pronounced than average gneissic appearance. The gneiss and schist have been mapped as a single unit by Butler and Vanderwilt (1933)" and by Singewald (1951).12 Schist predominates at the higher elevations of the Mosquito Range and in the area to the north and east of Climax. The regional trend of schistosity is northeast with varying dips to the east. Silver Plume granite and associated pegmatite intrudes the Idaho Springs formation. Silver Plume granite in many places and in the Climax district in particular has an irregular form, and many large and small inclusions of schist and gneiss occur within the granite. Granite predominates at the surface in the immediate vicinity of the area of hydrothermal alteration and extends for several miles to the northeast and southeast. As more schist is present at lower levels of the mine than in the upper levels, the suggestion is that the granite is sill-like in form,

Jan 1, 1956

By H. A. Wheeler

History ILLINOIS has so recently attained the third place in the oil production of the United States that few realize its great importance, or are aware of its highly profitable character. Since 1907 Illinois has furnished about 15 per cent. of the United States output and about 10 per cent. of the world's production. The value of the output in 1913 is estimated at $30,000,000, of which about $20,000,000 is profit. The present prosperity dates from 1905, but efforts have been made since 1865 to develop production and geologists have been very sanguine as to its future for over 25 years. Had the oil operators been as confident as the geologists, the field would have been opened at least 30 years earlier. For the rich Eastern Illinois oil field is located along the La Salle anticline, that was mapped 46 years ago by Professor Worthen in the

Jan 5, 1914

By O. T. Marzke, Robert F. Mehl

A study of the structures arising from the decomposition of the ß solid solutions in the Cu-Zn and the Cu-A1 systems is of peculiar interest in the study of the mechanism of precipitation from solid solutions. It is possible in these alloys, by varying the composition within the ß field, to precipitate from the same basic lattice phases having different lattice structures. It has been rather generally assumed heretofore that the type of structure originating from the decomposition of a solid solution— the Widmanstätten structure—-is determined by the lattice structure of the parent solid solution alone. In the first paper of this series1 evidence was advanced which threw doubt upon this hypothesis; but definite proof of the correctness or incorrectness of the hypothesis should be forthcoming from a study of these alloys, for if the structures originating, for example, from the precipitation of the a phase from ß and of the ? phase from the ß in the Cu-Zn system should be shown to be crystallographically different, the hypothesis would necessarily be held as definitely disproved. Furthermore, the newer proposal enunciated in the first paper of this series—that the origin of the Widmanstätten structure lies in a cooperation between the lattice of the parent solid solution and that of the precipitate-—which at present seems the only a1ternative hypothesis, would in such an event be given added weight. The work here reported shows that the Widmanstätten structures originating in the precipitation of the a phase from the ß and in the precipit'at.ion of the y phase from the y in the Cu-Zn system are indeed crystallographically different; and incidentally presents some new descriptive information on the Widmanstätten structure from a more general point, of view.

Jan 1, 1931

W. 0. HOTCHKISS,* Madison, Wis.-When we began to do geological field work in the Lake Superior region, we found a correlation in existence, and, as youngsters, accepted all that as settled. Both Mr. Allen and I, since that time, have seen a great many things that were not apparent nor visible to Van Hise, and those who worked with him; we realize now that the correlation was not final and that much remains to be determined concerning geology of the Lake Superior region. My attitude on this matter is that we should not publish an amended correlation as a final thing. We should avoid, in every way possible, foreclosing the minds of those who follow us in working in the geology of this region. As a matter of fact, no correlation can be final at present, because facts and data are accumulating so rapidly that every classification must be immediately modified to fit further observation. Consequently, my attitude in this matter would be, instead of saying that the iron formations of the Lake Superior region are all Middle Huronian, to say that there may be three Huronians-or four or five- we do not know. I believe it is better policy to hold to our present correlation. I do not believe there is any economic benefit to the mining man or the geologist working on problems relating to explorations for iron ore, that cannot be just as well solved by maintaining our present correlation, with a. wholesome idea of our lack of knowledge and the necessity for further detailed work. Then, if any new horizons are discovered in any particular range, the minds of the investigators will not be foreclosed because some one has said that all the iron formation is in the Middle so that there is no use looking elsewhere for it. There is use looking elsewhere, in many cases, as the ore deposits become exhausted.

Jan 1, 1920

By Thomas L. Garwood, F. C. Menk

I T is generally accepted that no method of coal cleaning except froth flotation is effective in cleaning dust. In the majority of coals mined in the United States the dust sizes contain a high percentage of impurities, hence the removal of the dust from the coarse sizes lowers the impurity content of these sizes. Dedusted coal is desired as a means of providing a better feed to cleaning plants because of increased efficiency in both dry and wet plants. In dry-cleaning plants, a dedusted feed makes for a pervious and uni¬form bed. With a dusty feed the fines tend to segregate in the feed stream and pass en masse over the air separators, causing a lack of uniform aeration and fluidity of the bed necessary to efficient cleaning. In wet-cleaning plants deducting of the feed often decreases the sludge problem to the point of eliminating the necessity of wasting wash water. It may be advantageous to eliminate sludge-settling equipment in favor of dedusting equipment, to provide the advantages of a dedusted feed to the wet-washing process. Dedusting advantages may include: (1) the removal of fusain, especially advantageous in plants washing coal intended for metallurgical coke; (2) prevention of the gradual build-up of solids in the wash water, with a consequent variation in the washing ability of the system; (3) prevention of the loss of dust to the sludge ponds, providing instead a fuel for local consumption or special markets.

Jan 1, 1943

By Frank Riddle

PRODUCTS made from the ores of the sillimanite group, and synthetic substitutes for them, have unique properties, and service tests prove that they are playing, and will continue to play, a major part in improvements in metallurgical processes. Also, they are examples of how comparatively useless, rare, or "museum" minerals have been made available in commercial quantities. Until research developed uses for them, the minerals had been observed only in small, scattered masses, or crystals. Improvements in ceramic processes and compositions have come about very gradually. In the last 10 or 15 years, several outstanding developments have been made. Of greatest interest to the mining and metallurgical engineers are those affecting the composition, necessitating the mining of new minerals, and improvements in ceramic products used in metallurgical processes.

Jan 1, 1932

By W. E. Remmers

THE defect in wire known as "cuppiness" has appeared and disappeared from time to time but the exact cause of its appearance or disappearance has not heretofore been known definitely. This defect is not limited to one particular metal or alloy but seems to be found at various times in all of the materials that are drawn into wire. Fig. 1 represents cuppy wire made from an aluminum alloy and Fig. 2 illustrates copper wire that became cuppy in drawing without intermediate annealing. Differences of opinion are current among the manufacturers of wire and in the literature (see Bibliography at end of paper), some believing that the source of the trouble lies in segregation in the wire rod, oxides, sulfides, slag, etc. ; others that the trouble is created by an unevenness of stress distribution across the section of the wire, usually thought of as being a function of die shape. All of the published work is of a qualitative rather than a quantitative nature. With this in mind, it was deemed advisable to make a study of the shape of the wire-drawing dies, as well as the oxygen content of the copper to be drawn.

Jan 1, 1929

By Chris Mills

The role of gravity separation in the mineral industry is briefly considered in perspective. The mineralogical and laboratory approaches to gravity process design are examined with emphasis on process technology selection. The equipment available for small scale and pilot test-work is discussed, particularly in regard to scale-up and the acquisition of reliable, accurate data. Transposition of performance data from pilot scale to plant scale is explained. The available types of full scale gravity separation equipment are discussed with emphasis on large high-capacity units. Plant layout and selection of ancillary equipment are considered.

Jan 1, 1978