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By R. W. Raymond

[NOTE.-This paper was presented at the Pittsburgh meeting in a partially completed form, and I fully expected to obtain, before the period of its publication, both the data and the leisure required for its completion. The hygiene of collieries was to have been separately considered, and the sanitary conditions of various metallurgical industries connected with mining were to receive an extended discussion, while at the same time the points treated in the paper as presented at Pittsburgh were to have more ample illustration from American and European sources. Delay in obtaining expected information, and the continuous pressure of professional work, have prevented hitherto the execution of this plan ; and I can now publish only a portion of what I had designed to contribute to the subject. In the meantime this portion, but slightly changed, has been included as a chapter on the Hygiene of Metal Mines in a work entitled Hygiene and Public Health, edited by Dr. A. H. Buck, of New York. An excellent chapter on the Hygiene of Coal Mines, contributed to the same work by Mr. Henry C. Sheafer, of Pottsville, affords me an opportunity to supply one of the deficiencies above alluded to. Mr. Sheafer's chapter contains much material in the way of explanations not required by professional readers; and he moreover devotes a considerable space to the explosive gases, falls of roof, and other causes of accidents to life or limb-a branch of the subject not belonging strictly to hygiene. I therefore make extracts only from his treatise.-R. W. R] IT is convenient to divide mines, with reference to this subject, into two classes, collieries and metal-mines. Subterranean quarries, rock-salt mines, etc., present no conditions requiring them to be separated from the latter class.

Jan 1, 1880

By John Griffen

THEORY HYDRAULIC classification as explained by Rittinger and others was largely restricted to conditions wherein the free-falling velocities of the particles were conceived as governing the separations effected (see chapter 9). The laws governing classification under free-falling conditions have been summarized by Chapman and Mott as follows: 1 Nomenclature r represents, in a particle of irregular shape, the round-hole screen through which the particle would pass, or some other linear dimen¬sion of the particle equivalent to d, the diameter of a sphere. s, the specific gravity of the particle. 1, the specific gravity of the water used as a medium. K, a constant. W, the velocity of the water. In an Upward Current of Water 1. A particle will move upward if [W > KVr(s-1)] and, by suitably regulating the speed of the water current, the larger and heavier particles may be made to fall downward against the current, leaving the smaller, lighter particles in suspension in the current. 2. Particles such that [T1= s2-1] cannot be separated in an upward-current classifier with any one velocity of current. Coal particles having a specific gravity of 1.35 cannot be separated from refuse particles of 2.5 sp. gr. Unless 2.5-1 the ratio of diameters is less than [1.35-1 or 4.3 to 1,] and the raw coal must be screened to size limits within this ratio if they are to be separated. Cone¬-shaped vessels or vessels of other shapes that allow the use of&apos; different velocities of current at different points in the flow are used to modify this limitation. 3. During the initial stages of motion, coal particles ascend more rapidly than refuse particles of the same size. 4. A particle will ultimately fall if [W < KVr(s-1).] If particles of

Jan 1, 1950

By L. C. McCabe

THE object of the present investigation was to discover a physical basis for rank differentiation of coals, particularly the coals of the Illinois basin. Vitrain1 was selected as the most appropriate coal material to use in the investigation, because of its homogeneity and ease of acquisition and handling. Previous Investigations.-Hoffman and Jenker2 have shown that their index of reflection is a characteristic of coal rank and that the Leitz slit microphotometer may he used in determining the different intensities of reflection. Zhemchuzhnikov3 measured the luster of several Russian coals with a color analyzer and found that the degree of luster was indic-ative of rank. Luster-volatile matter curves based on data from Sucan and Donetz coals were satisfactorily used for determining the rank or volatile content of other coals after the luster strength was determined. In 1934 Fisher4 reported refractive indices of 1.76 for bituminous vitrain and 1.87 for semibituminous vitrain. Investigation of Angle of Polarization.-Early in the present investiga-tion several determinations of the refractive indices of the vitrains were made by immersing the minus 150 plus 200-mesh powder in oils. It was found that all the samples fell within the range 1.6 to 1.8. However, difficulty was encountered in securing oils in this high index range that were closely enough spaced to separate some of the coals. The writers made a number of determinations of the angle of maxi-mum polarization from the polished surfaces of the vitrains and derived their refractive indices by the procedure described in the follow-ing paragraphs.

Jan 1, 1937

By Harry Morgan

ONE of the direct results of the increasing number of oil wells drilled to greater depths has been the development of new types of bits. These bits should resist the abrasive action of drilling and give the greatest footage before bit changes become necessary on account of dulled cutting edges. The loss of drilling time caused by changing bits becomes more important as the well becomes deeper, because the whole drill pipe must be unscrewed to make; each change. Under ordinary conditions the change takes: 2 1/2 hr. for round trip at 4000 ft., 3 hr. for round trip at 5000 ft., 4 hr. for round trip at 6000 ft., 5 hr. for round trip at 7000 ft. In other words, the time to change a stand of drill pipe (90 ft.) varies from 1 2/3 min. at 4000 ft. to 23 min. at 8000 ft. In general, the formation in the deeper zones is harder and dulls bits more quickly than the formations nearer the surface, therefore even a small increase of hole drilled per bit will decrease costs and increase speed of drilling.

Jan 1, 1929

By Thomas L. Kesler

THE Cartersville mining district, 35 miles northwest of Atlanta, Ga., has been of varying but continuous importance in the southern mineral industry during the past century. Noted chiefly for its production of brown iron ore, manganese oxide ores, barite, sienna, and magnesian limestone, the district and its environs have produced brick and tile clays, slate, gold, bauxite, and graphitic schist. Minor deposits of serpentine, sericite schist, copper ore, and red iron oxide have been prospected. The obvious deposits of brown iron ore, together with some associated specular hematite, were mined out years ago, although a little ore was left in the workings. Moderately steady production of sienna reached a peak about 1930, then declined rapidly. Manganese mining passed through a relatively active period from the World War to 1931, but has subsided to a small but rather constant output for the Birmingham market. However, the White Manganese Corporation has prepared for possible increased production by constructing a new washer capable of handling about 300 tons of ore per day. Principal activity in the district proper has centered for some years in the production of barite and magnesian limestone. GENERAL GEOLOGY Geologic relations of the ore deposits of this district are more or less similar to those of many Appalachian districts. The lowermost Cambrian formation, heretofore called Weisner1 in this region, supposedly partly or wholly equivalent to the Erwin and Hesse quartzites as recognized to the northeast, is overlain conformably by the Shady [+] formation, also of Lower Cambrian age. In the Cartersville district, the sedimentary rocks of these formations were folded with increasing intensity eastward, and were recrystallized.

Jan 1, 1940

By William M. Brewer

Until quite recently, in fact within the past two gears, but little attention has been given to the outcrops on the west coast of Vancouver Island, and their copper-contents. During the past few months the writer has been engaged in examining and developing some of these prospects. In many respects he has found characteristics associated with these prospects which, in his experience, are unique. In the first place, nearly all the outcroppings which overlie chalcopyrite-ore along the west coast of the island are composed of a high-grade magnetite. The magnetic qualities of some of these outcrops arc so pronounced that the magnetite possesses polarity. Although the writer hinlsclf had no analyses of this magnetite made, yet from its appearance he can readily believe that analyses made for other parties, which show a yield&apos; of 62 or 63 per cent. of metallic iron, with only traces of phosphorus and silica, are correct. At a very shallow depth, masses of chalcopyrite, yielding in some instances as high as 32.6 per cent. of copper, occur associated with the magnetite; and in one instance, which recently came under the writer&apos;s observation, a solid body of high-grade chalcopyrite, fully 4 feet in thickness, occurs Within 6 feet of ; the surface. Usually this solid sulphide-ore carries low values in gold. Probably ail average of&apos; $2 per toil would be fairly representative. But in some instances development has determined the occurrence of narrow stringers of pyritous quartz, associated with the sulphide-ores, which yield by assay more than $20 per ton in gold. In the districts examined by the writer, the country-rock is usually crystalline limestone, with dikes of igneous rock as intrusions. Sometimes the outcrops of magnetic iron-ore are

Jan 1, 1900

By Samuel Thomas

The specimen of anthracite coal which I hold in my hand, insignificant as it may appear to the casual observer, speaks volumes to me and to the initiated, as it suggests and represents the entire evolution of the use of anthracite coal in the manufacture of pig-iron, the growth and development of which it is my purpose to review here to-day. During our recent visit to the Mountain Copper Co.&apos;s works at Keswiek, I picked up this piece of coal from a pile of anthracite lying in the yard, asked Mr. Edwards, the manager, a countryman of mine, where it came from, and, to my surprise and delight, discovered that it had been brought all the way from Wales, and had come out of the identical vein which my father opened near Yniscedwin, about eighty years ago. I had no idea, before this incident, of contributing to the already full and complete programme of the day; but, being requested by our distinguished President and Secretary to do so, I consented to relate here the story which this remarkable find naturally brought back to my mind.

Jan 1, 1900

By Ronald R. MacDonald

There is an ongoing need for the abstracting and coding of new information in the energy and environmental studies field for addition to the BIRS system. There are approximately 3000 bibliographic entries coded into the BIRS system. The bibliographic retrieval system was designed to be run by the general data management System 2000. The information system with entries of coal research, land reclamation and other energy and environmental studies is up and on line. As more entries are coded they are loaded into the system.

Jan 1, 1977

By W. K. Tony Seiler

Further development of mechanical boring machines for hard and abrasive rocks will be effected by the development of more efficient rock cutting tools or the evolution of entirely new rock excavating principles. Presently the cutting tools suitable for extremely hard rocks and successfully and economically used with raise and tunnel boring machines are tungsten carbide insert big hole cutters. This paper explains the design, rock cutting principles, and actual boring operations to illustrate the capabilities and applications of tungsten carbide (TC) insert cutters. While the rate of borehole advance may fall short of the rapid excavating results achieved with soft rock boring machines, the cutter described in this paper may prove to be the most suitable tool in hard rock excavation for many years to come. DEFINITION OF HARD ROCK Existing bored excavations in hard abrasive rocks are proof of the economic application of new methods and mechanical rock boring in the mining industry. Most of the experience in cutting hard to extremely hard rocks has been gained in raise boring where relatively short and small diameter openings are bored. This poses a lesser risk regarding cutter cost than a long and large diameter tunnel and has therefore promoted the testing of various cutter products. Many types of rocks and geologic conditions were en- countered and actual test data was recorded in materials of up to 100,000 psi uniaxial compressive strength. To clarify the term hard to extremely hard, a 1970 interpretation of rock strength which was recently used is adopted and expanded in this paper.

Jan 1, 1971

By Olaf Hondrum

CHURN drilling equipment at Bagdad consists of two Bucyrus Erie 27-T model drills and one 22-T drill with gasoline engines. The drilling tools weigh approximately 1600 lb. The holes are drilled with 7-in. bits which are heated in an oil burning furnace and sharpened in an electrically powered bit sharpener. A service truck brings the bits to the drills and takes the dull bits back to the shop. The bits weigh around 250 lb. when new and are handled by drill crews without any mechanical handling device. When the management decided to start open- pit operations in 1945 the ruggedness of the terrain was one factor that led to the purchase of the small 22-T model drill. The orebody lies on both sides of Copper Creek Canyon. The sides of the canyon are steep and are cut by numerous narrow branch gullies. The drill had to travel over roads that were narrow and steep. It proved adequate for drilling the capping formation and is still in use.

Jan 1, 1950

By Joseph Newton

MUCH the same story can be told about the copper industry for the year 1944 as for the three preceding years. Operators report few or no technical changes at their plants and the main endeavor has been to maintain high production with existing equipment. No large new installations have been made to increase plant capacities and apparently over-all copper production has passed its maximum. The present decline in copper production results partly from the severe labor shortage. As is true of most industries; the outstanding fact about the copper industry during the past few years has been its tremendous and sustained production which has been maintained in spite of serious shortages in material. labor, and technical personnel. The figures in Table I give a concrete example of how production has been increased at one large smelter in the United States-the Garfield plant of the American Smelting and Refining Co. at Garfield. Utah. These figures, reported by W. G. Rouillard. superintendent. give the production of the Garfield plant for the five years 1940-44 inclusive. The total blister production

Jan 1, 1945

By H. S. Gieser

THE flotation of oxidized silver, ores offers an interesting problem to the operating metallurgist, who has to treat this material. The advances made in the art of selective flotation by the use of newer collectors with accelerating and inhibiting reagents suggests that there should be something to help to decrease tailing losses. For many years there was no working hypothesis, so the subject was approached more or less in the dark, but with the publication of a paper by Taggart, Taylor and Ince1 giving results of flotation tests with many organic compounds and presenting a tentative theory, a better foundation has been laid and henceforth progress should be more rapid. Over a period of one and one-half years there was much experimentation with flotation of oxidized silver ores at El Tigre, Sonora, Mexico. The material coming to the mill was straight sulfide ore in a silicified rhyolite gangue, the ore minerals being sphalerite, galena, pyrite and tetrahedrite. This came largely from the lower levels of the mine. With the approaching exhaustion of these orebodies, attention was turned to oxidized ores left behind during higher prices of silver. Of late oxidized ore has been at times 25 per cent. of mill tonnage. Aerofloat 25, in considerable quantity, together with ethyl xanthate, has been used in the mill. The former raises large quantities of "insoluble" or gangue, which is difficult to reject when the density of the tailing pulp approaches 33 per cent. solids, as it did during periods of water scarcity. The mill tailing at times contained as much as 5 oz. of silver on a 32-oz. mill head.

Jan 1, 1931

By Julian E. Tobey

A MEMORABLE year has just passed in the field of coal utilization. Because of the war, oil conversions in industrial, commercial, and domestic installations have been made to the equivalent of 20,000,000 tons of coal. The war emergency has resulted in a great shifting of various types of coals to various markets. Huge tonnages of metallurgical-quality coals have been withdrawn from steam and domestic business and sent into the iron and steel industries. Marginal coals have replaced these coals in the steam and domestic field.

Jan 1, 1944

By F. I. Grace, L. E. Murr

The mechanical responses and residual defect structures in 70/30 brass and type 304 stainless steel following explosive shock loading and cold reduction by rolling have been studied. A distinct relationship was observed to exist between the residual mechanical properties and micro structures observed by transmission electron microscopy. Shock-loaded brass deformed primarily by the formation of coplanar arrays of dislocations and stacking faults at lower pressures, and twin-faults (deformation twins and €-martensite bundles) at higher pressures (> 200 kbar). The micro -structures of cold-rolled brass were characterized by dense dislocation fields elongated in the rolling direction. Stainless steel was observed to deform by the formation of dense arrays of stacking faults at lower shock pressures and twin-faults at high shock pressures (>200 kbar). Lightly cold-rolled stainless steel deformed similar to low Pressure shock-loaded stainless steel, but transformed to a&apos; martensite in heavily cold-rolled stainless steel. Discontinuous yielding was observed for the heavily cold-rolled stainless steel, and stress reluxution in the weyield region for cold-rolled and shock -loaded stainless steel was interpreted as an indication of the ability of twin-faults and stacking faults to act as effective barriers to dislocation motion. A simple model for the formation of the planar defects and a&apos; martetnsite is presented based on the propagating of Shochley partial and half-partial dislocations. A considerable effort has been expended over the past decade in an attempt to elucidate the response of metallic-crystalline solids to the passage of a high velocity shock wave (e.g., smith,&apos; Dieter,2 and zukas3). While it has been possible to obtain relevant information pertaining to the residual defect structures and mechanical properties, there have been few rigorous attempts to draw a direct comparison between these structures and properties. In addition, numerous investigators have recently observed the occurrence of deformation twinning in shock deformed fcc metals (e.g., Nolder and Thomas,4 and Johari and Thomas5), but little attempt has been made to elucidate the mechanisms of formation of these defects. Comparative data for metals deformed by shock-loading and the same metals deformed by more conventional modes of deformation such as cold-reduction by rolling is also generally lacking. The present investigation therefore has the following objectives: 1) to examine the mechanical properties of some explosively shock loaded and cold-rolled fcc metals of low stacking-fault energy as a function of their residual substructures; 2) to present a simple model for the formation twin-faults and related defect structures in the low stack-ing-fault energy materials of interest (70/30 brass, ySFg= 14 ergs per sq cm; and 304 stainless steel, ySF = 21 ergs per sq cm); 3) to make some deductions with regard to the residual characteristics of dislocation and planar defect substructures in cold rolled and shock loaded 70/30 brass and type 304 stainless steel. In particular, it was desirable to characterize the residual hardening effects of particular deformation substructures. I) EXPERIMENTAL PROCEDURE Sheet samples of 70/30 brass (0.005 and 0.15 in. thick; annealed at 659°C for 2 hr) and type 304 stainless steel (0.007 in. thick; annealed 0.25 hr at 1060°C) of nominal compositions shown in Table I were cold-rolled in one direction only to produce reductions in thickness of 15, 30, 45, 60, and 75 pct in the brass; and 5, 15, 25, 35, and 45 pct in the stainless steel. Identical sheet samples in the annealed (unrolled) state were subjected to plane compressive shock waves to various peak pressures ranging from 0 to 400 kbar in the brass and 0 to 425 kbar in the stainless steel; and with a constant peak pressure duration of approximately 2 microseconds. A detailed description of the shock loading technique has been given previously.6 Tensile specimens 1.0 in. in length and 0.125 in. in width were cut from the cold-rolled sheets (tensile axis parallel to the rolling direction), and the shock-loaded sheet specimens. Stress (load)-strain (elongation) measurements on the tensile specimens were made on a Tinius-Olsen load-compensating tensile tester using a strain rate of 2.7 x 10-3 sec-1. Tensile tests were repeated at least twice, giving essentially the same results. Stress relaxation measurements in the preyield region were also made using an initial strain rate of 5.4 x 10-4 sec-1. In addition to tensile and stress relaxation measurements, Vickers microhardness measurements were made on all samples. A total of 100 microhard-ness readings were obtained for each specimen following a light electropolish to ensure uniform surface conditions for all tests. The hardness averages ob-

Jan 1, 1970

By Persifor Frazer

General Geology of the Northern Black Hills. The " Black Hills of Dakota," to the northern part of which the following observations apply, occupy a position on either side of the boundary between Wyoming and South Dakota, approximately between 103" 15&apos; and 104" 48&apos; of west longitude and 43 15&apos; to 43" 50&apos; of north latitude. The area is roughly 4160 square miles.* (See Plate I.) As has been pointed out by Profs. H. O. Hofman, I?. R. Carpenter and others, and illustrated by Mr. Newton in the publications of the United States Geological Survey, these hills are made up of a large number of the known formations from the Archean to the Tertiary, which latter constitutes the border of the region. The mining operations are largely confined to the interior of this area, and the centers from which they are conducted (Deadwood, Lead City, Galena, etc.) are situated near the line of junction of the Archean schists and quartzite, supposed to represent the Potsdam Sandstone of the N. Y. series, or the lowest of the Paleozoic measures. The Archean or pre-Paleozoic rocks consist mainly of a mica-schist in which hornblende and garnet are frequently

Jan 1, 1898

By Frank L. Nason

In the year 1904 an eminent Swedish geologist prepared a report on the iron-ore reserves of the world. His estimates follow: Countries. Tons. United States,.1,100,000,000 Great Britain,.1,000,000,000 Germany,.2,200,000,000 Spain,.. 500,000,000 Russia and Finland,...... 1,500,000,000 France,..1,500,000,000 Sweden,..1,000,000,000 Austria-Hungary,....... 1,000,000,000 Other countries,1,200,000,000 Total,.10,000,000,000 The iron-ore allotted to the United States by the Swedish geologist is barely sufficient to last 20 years at. the present rate of consumption. On the other hand (according to Edwin C. Eckel,&apos; from whom the above and following statistics are quoted), there is hardly need for worry on the part of our iron industries for the next two centuries or more. Upon the basis of careful work by the U. S. Geological Survey, in which Mr. Eckel has taken an important part, the following estimates are definitely, but by no means finally, given for the United States: District. Tons. Lake Superior District,... 1,500,000,000 to 2,000,000,000 f red hematite,.. 1,000,000,000 Alabama, brown hematite, hematite, . 725,000,000 red hematite,.. 200,000,000 Georgia, { brown hematite, . 125,000,000 Tennessee, { red hematite,.. 600,000,000 Tennessee, { brown hematite,hematite, . 225,000,000 f red hematite,.. 50,000,000 Virginia, } brown hematite, . 300,000,000 Total,..4,725,000,000 to 5,225,000,000

Jan 1, 1913

US 4,181,703-Removal of magnesium impurity from phosphate rock. Crushed screened ore containing more than 0.3% by weight of magnesium is slurried with sea water, acidified with sulfuric acid to a pH value not lower than 2 5, and filtered and washed before the neutralization point is reached. W. Wengeler, F. Wolstein, and E. Hoffman, assigned to Uhde G.m.b.H. Jan. 1, 1980 4 pp (423-167) Filed: 11-18-77 (852,918)

Jan 1, 1982

By David White

THE environmental conditions under which coals are deposited are revealed by the stratigraphy of the coal basins and coal beds and by the details of the structure and the physical constitution of the coals themselves. THE LAND SURFACE Generally Low Relief or Base Level In the Paleozoic coal fields, which have longest been worked, are most important, and are best known, we find relations, in general, as follows A post-Mississippian uplift with, in most cases, very moderate deformation, followed by erosion by which the uplifted regions, especially the bolder of the new topography, were largely worn down, while the older and less deformed regions were more or less extensively base leveled. Base leveling of most of the region continued as the deposition of coal measures proceeded. Consequently, in most coal fields the Pennsylvanian, or upper Carboniferous, lies unconformably on the Mississippian or on older formations. There are but few regions in which sedimentation is seen to have been apparently continuous from the Mississippian into the Pennsylvanian ("Coal Measures").

Jan 1, 1925

By Guy Ruggles

IN this paper the authors aim to chronicle the experience and salient points brought out in changing flotation reagents at a concentrator which had probably been using a minimum amount of oil at a minimum cost per ton, to a more complicated system requiring a partial chemical control. The original oils were coal tar and pine oil. The new reagents are line, xanthate and pine oil. It was found that there were no insur-mountable difficulties and eventually the cost of the new reagents per ton of ore proved to be very little more than that of the old. LIME PLANT When the question of handling lime came up there were two propositions open: (1) to handle the lime dry; (2) to handle it wet in the form of an emulsion. Granting that a dry lime feeder would function properly, delivering lime uniformly, the chief objection was the dust that would be raised when these feeders were being charged or operated, as the only possible location was on a gallery beneath which men were working. With this objection the handling of lime as an emulsion seemed to he the better scheme. The lime plant which was first installed was for experimental work on one section. This was gradually changed and developed until it was of sufficient size to accommodate 20 sections. The various changes will not be discussed and the following description deals only with the fully developed plant. Crude as it is, and perhaps somewhat expensive to operate, the lime-handling plant has been quite successful. Much has been learned which will pave the way for a better installation in the future.

Jan 1, 1927

FROM north to south activity is picking up through- out the Labrador Trough-already shown to be one of the world&apos;s great iron ore provinces. Center of current activity and interest lies in the mid-southern part of the trough as drills, equipment, and . . . money start to pour into the area near Mt. Wright and Wabush Lake. First major announcement in the area came early this spring when J&L and CCI outlined an estimated billion-ton deposit for "future" operations. Later impetus came from rumored railway for US Steel&apos;s Quebec Cartier projects in the Mt. Reed area slightly to the south. As this issue went to press US Steel&apos;s request for bids on railway and hydroelectric construction, plus IOCC&apos;s decision to step up the time- table on its program in the Wabush Lake area east of Mt. Wright, triggered a flurry of other announcements involving many of the top U. S. and Canadian iron ore firms. Do not look for most of these place names in the average atlas . . . they aren&apos;t there yet, but they soon will be.

Jan 6, 1958