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Manganese nodules are essentially a surficial resource-there are four times as many nodules on the surface of the deep ocean floor as in the next 3 ft of underlying sediment. Target mine sites in the North Pacific occur in water 12,000 to 18,000 ft deep. The mining technique is comprised of four major factors: the mining device, lifting method, surface vessel, and ore transport. Certain deep-ocean mining proposals are revolutionary in character. Current research has tended to construct simple but flexible devices to work at the great depths and corrosive environments of the deep-ocean floor

Jan 4, 1975

By J. F. Stiehr, R. L. Sanford, T. L. Myers

This paper summarizes the development of a Directory of Computer Programs Applicable to US Mining Practices and Problems. The directory is funded by the US Bureau of Mines and includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various US government agencies. General references to computer applications throughout the mining industry are discussed as well as the availability of programs to interested organizations or individuals.

Jan 9, 1979

WITH the present mobilization program in full swing and the enrollment in engineering colleges dropping off, many solutions are offered to relieve the shortage of trained men in the engineering profession. Industry can absorb about 30,000 engineers annually, according to the Engineers Joint Council, and forecasts indicate that the number graduating will have dropped from 38,000 in 1951 to about 12,000 in 1954. If this condition were to continue there would probably not be enough people with technical training to run industry in four or five years.

Jan 12, 1951

By F. N. Kissell, R. A. Jankowski

The US Bureau of Mines, in close cooperation with the mining industry, has recently established several improved face ventilation techniques for longwall mining systems. These include coursing the primary face intake from tailgate to headgate, installing curtains at the intake end of the longwall face, and identifying improved techniques for measuring face ventilation parameters on longwall sections. Applying these techniques throughout the mining industry should reduce the health hazard associated with excessive exposure to respirable dust.

Jan 1, 1984

By J. J. Gilman

WHEN a cleavage crack that is moving through a crystal intersects a screw dislocation, a jog is created in the crack front. As the crack continues to move, the jog leaves behind a cleavage step. This mechanism was proposed by Amelinckx and Votava,' Pratt, bnd Gilmanh t about the same time. At that time the evidence for the mechanism was largely indirect. Other evidence has been presented by Low, Bilby and Smith,5 and Forty.' It is the purpose of this paper to present more direct evidence of this mechanism and to show that observations of cleavage steps can be used to detect screw dislocations. Experimental Lithium-fluoride crystals that were purchased from the Harshaw Chemical Company, as well as natural mineral crystals and metal crystals, were used in the experiments. Although cleavage steps can be observed on transparent crystals with a metallurgical microscope, the contrast is poor. Marked improvement in the contrast is obtained by depositing thin (1000A) films of silver or aluminum onto the surfaces. The contrast also can be improved by using a phase-contrast microscope, but the simpler silvering method gives just as good results. Tolansky interferometric microscopy, and electron microscopy were used to measure the heights of cleavage steps. The etching techniques developed by Gilman and Johnstonh ere used to detect dislocations in the LiF crystals. Results The dislocations that create cleavage steps can originate in three ways: a) They can be grown into crystals b) They can be introduced by plastic deformation prior to cleavage c) They can be formed just in front of the tip of a propagating cleavage crack.' These three situations will be considered in turn. Grown-in Dislocations—It is not possible to see the individual monomolecular cleavage steps that emanate from isolated screw dislocations in crystals.

Jan 1, 1959

By Clement K. Chase

ION exchange recovery of uranium has been proved successful in many operating plants in various parts of the world. First used in column plants processing clear liquors, ion exchange has more recently been applied in basket resin-in-pulp systems. A logical further development is the application of truly continuous processing techniques to the ion exchange recovery of metals, since previous systems have been semicontinuous at best. Column ion exchange is a valuable technique and has been used extensively in South Africa and elsewhere. However, it requires clear liquors. To produce these clear liquors, considerable investment in filter plant and clarification equipment is necessary. In the cases where it is very difficult or impossible to produce clarified liquors, column ion exchange is not so useful. Moreover, some liquors suffer from post-precipitation after clarification, which can become a serious problem.

Jan 9, 1957

By R. H. Frank

IN the investigation of the effect of the time of heat on slag volume, no attempt was made to vary the usual practice at the Bonney-Floyd Co., such as selecting special-purchase scrap or cleaning foundry returns. The data were collected from seven normal heats, including four medium carbon, two medium manganese-molybdenum and one nickel-chrome-molybdenum. These heats were made with our normal practice and no special instructions were given the melters except to make sure that all slag-making materials were weighed and that no slag was lost during the melting, refining or tapping. After the stopper was set in the ladle, it was carefully weighed and the heat was tapped. As soon as the heat was slagged on the pouring floor, the nozzle was plugged with mud, to preclude the possibility of losing any slag while the ladle was being conveyed to the scales. The ladle, containing all of the slag, was weighed and the difference between this weight and the original weight was taken as the slag weight.

Jan 1, 1947

By Francis B. Foley

THE casting of steel in large molds brings into play all of the undesirable effects that result inevitably from slow cooling. The origin of the molten metal, whether basic or acid open hearth or electric furnace, has little if anything to do with the phenomena involved. If the quantity of molten metal to be cast in a single mold is large enough, there is very little one can do about it-the metal will cool so slowly that 'nothing one can do, other than to provide as good feeding as practicable from an adequate reservoir of metal in the sink head, will be of any avail. Recently we have had occasion to cast a 108-in. octagon ingot weighing 545,700 lb, necessitating the combining of metal from three 100-ton open-hearth heats. This is one of the largest ingots ever made. The body of the ingot weighed 448,800 lb, which includes a bottom pool of about 7500 lb of metal, and the sink-head weight was 96,900 lb, or about 18 pct of the total weight.

Jan 1, 1947

By F. C. von der Weid

The mining district of Sao Fidelis, in the northern part of the State of Rio de Janeiro, is situated on the Paraiba River, where it crosses the Serra do Mar (Mountain of the Sea), in the center of a mountainous country having numerous graphitic outcrops. For a long time, these outcrops were irregularly explored by local people, who had little means and no technical advice. A few years ago, the Cia. Brasileira de Mineracao de Grafite took over the control of some of the more important outcrops and entrusted to me the task of studying the ores and establishing a flowsheet for a pilot plant to be situated in Sao Fidelis—the ore to be concentrated being mostly of a very high grade. Mineralization and Ores The rocks of the district are mostly gneiss and crystalline schists, with occasional interstratification of dolomitic limestone belonging to the Archean Brazilian Fundamental Complex. The general direction of the beds is roughly between 60' and 80°E., with variable dip, generally nearly vertical. Mostly, direction and dip of the graphitic outcrops is concordant with the embanking gneisses or schists. These outcrops seem to be aligned in two or three parallel zones (Padua, Sao Fidelis, Mac- abu), the Sao Fidelis zone being the best known and the most important to date. Two outcrops of the Silo Fidelis zone, Saudade and Sao Benedito, are now being exploited. Mining has beer] carried out, so far, on a small scale. The mineralization consists of a vein of nearly massive graphite in a very compact, partially granitized gneiss, with vertical dip. The vein is most irregular, nith nests and lenses irregularly distributed along the fracture plane. The ore consists chiefly (particularly in Sao Benedito) of massive graphite appearing and disappearing along the main direction of the vein, forming a succession of irregular lenses in a sort of rosary design. The average width is more or less one foot, with variations from zero to 6 feet. The lode minerals are quartz, a little feldspar and garnet (the latter having its origin perhaps in the embedding gneisses), with rare ferruginous clays on the outcrops. In Saudade a little pyrite, pyrrhotite and chalcopyrite is found occasionally, as well as a carbonaceous mineral, very light, black and shiny, with conchoidal fracture, looking like a sort of jet. The composition of this mineral has not yet been established, but it seems to be very complex. The mineralization seems to be hydro-thermal at a rather low temperature, perhaps mesothermal. The paragenesis, according to samples from Saudade, seems to be as follows, the earlier minerals being listed first: pyrrhotite, pyrite, chalcopyrite, with quartz concomitant to the three and graphite formed later. Age of the mineralization is still uncertain, owing to the very in-

Jan 1, 1947

By F. C. von der Weid

The mining district of Sao Fidelis, in the northern part of the State of Rio de Janeiro, is situated on the Paraiba River, where it crosses the Serra do Mar (Mountain of the Sea), in the center of a mountainous country having numerous graphitic outcrops. For a long time, these outcrops were irregularly explored by local people, who had little means and no technical advice. A few years ago, the Cia. Brasileira de Mineracao de Grafite took over the control of some of the more important outcrops and entrusted to me the task of studying the ores and establishing a flowsheet for a pilot plant to be situated in Sao Fidelis—the ore to be concentrated being mostly of a very high grade. Mineralization and Ores The rocks of the district are mostly gneiss and crystalline schists, with occasional interstratification of dolomitic limestone belonging to the Archean Brazilian Fundamental Complex. The general direction of the beds is roughly between 60' and 80°E., with variable dip, generally nearly vertical. Mostly, direction and dip of the graphitic outcrops is concordant with the embanking gneisses or schists. These outcrops seem to be aligned in two or three parallel zones (Padua, Sao Fidelis, Mac- abu), the Sao Fidelis zone being the best known and the most important to date. Two outcrops of the Silo Fidelis zone, Saudade and Sao Benedito, are now being exploited. Mining has beer] carried out, so far, on a small scale. The mineralization consists of a vein of nearly massive graphite in a very compact, partially granitized gneiss, with vertical dip. The vein is most irregular, nith nests and lenses irregularly distributed along the fracture plane. The ore consists chiefly (particularly in Sao Benedito) of massive graphite appearing and disappearing along the main direction of the vein, forming a succession of irregular lenses in a sort of rosary design. The average width is more or less one foot, with variations from zero to 6 feet. The lode minerals are quartz, a little feldspar and garnet (the latter having its origin perhaps in the embedding gneisses), with rare ferruginous clays on the outcrops. In Saudade a little pyrite, pyrrhotite and chalcopyrite is found occasionally, as well as a carbonaceous mineral, very light, black and shiny, with conchoidal fracture, looking like a sort of jet. The composition of this mineral has not yet been established, but it seems to be very complex. The mineralization seems to be hydro-thermal at a rather low temperature, perhaps mesothermal. The paragenesis, according to samples from Saudade, seems to be as follows, the earlier minerals being listed first: pyrrhotite, pyrite, chalcopyrite, with quartz concomitant to the three and graphite formed later. Age of the mineralization is still uncertain, owing to the very in-

Jan 1, 1947

By Thomas V. Falkie

The three basic ingredients of fertilizers are nitrogen, phosphorus, and potassium. Nitrogen comes from natural gas or other sources and is usually a "manufactured" ingredient. Phosphorus and potassium come from mineral sources which are mined in open pit and underground mines all over the world. Phosphorus is one of the 15 chemical elements needed to sustain life. Along with nitrogen and potassium, it is essential to the fertility of the soil and to the growth of plant life. Plants require phosphorus for proper soil conditions, early root formation, and crop maturity. Humans and animals require phosphorus for bone and tooth development. The primary raw material for phosphorous fertilizers is phosphate rock. It is found and mined in many areas of the world. Morocco, the United States, USSR, Tunisia, and some Pacific Islands are the leading rock producers. Other sources of phosphate are guano, bone meal, and other natural organics, but these comprise a very small percentage of all phosphate used. Phosphate rock in the United States is mined in Florida, North Carolina, Tennessee, Idaho, and Montana. Florida alone produces about 70% of all the rock mined in this country, mostly from a 20 X 30 mile area in Polk and Hillsborough Counties in central Florida known as the Bone Valley district. There are phosphate reserves in many parts of Florida, and within the past three years mining has begun in north Florida in Hamilton Country (see Fig. 1). In 1967, world phosphate rock production was about 75 million short tons (st). The United States produced about 35 million st (about 47%) of which Florida produced about 25 million st (about one-third of world production). According to Phosphorus and Potassium magazine (Mar./

Jan 1, 1969

By J. E. Worthington, W. H. Spence, I. T. Kiff

Gold was discovered at the Haile mine in Lancaster County, South Carolina, in 1827 or 1828, and since that time the mine has been worked intermittently by both open-pit and underground methods until its forced closure in 1942 by World War II. Production figures are incomplete, especially for the early years, but the total gold produced is estimated to have been greater than 200,000 oz. Thus, the Haile mine has been the most productive gold mine in the eastern United States. The upper, residually enriched ores were relatively rich, but the bulk of the production has come from the mining of lower grade ores. General Geology The Haile mine is located in late Precambrian or early Paleozoic rocks of the Carolina slate belt at the edge of the Atlantic Coastal Plain [(Fig. 1)]. The metamorphic grade is lower greenschist facies and the rocks have been folded into a sequence of northeast-trending isoclinal folds. The gold is associated with siliceous, pyritic, and kaolinized felsic pyroclastic and tuffaceous rocks in an interbedded volcanic and volcanoclastic sequence of felsic to mafic tuffaceous rocks and argillaceous sediments [(Fig. 2)]. The ore bodies occur in two northeast trending zones approximately 500 m apart; each zone is 30-70 m wide and 600 m or more in length, with possible extensions to the east beneath the Coastal Plain sediments. Mineralogy. Gold in the Haile mine is always associated with siliceous and/or pyritic ores. The gold occurs in at least three states: As native gold as originally deposited; as residual gold derived from the breakdown of pyrite; and as gold included in pyrite. Major associated minerals in addition to quartz and pyrite are kaolinite, sericite, and iron oxides. Minor molybdenite, arsenopyrite, pyrrhotite, copper sulfides, sphalerite, rutile, and topaz are also present. Petrology. The gold-bearing ore zones vary from highly siliceous rocks to pyritic massive sulfide lenses. This variation is most easily seen today along strike from the Haile pit to the Red Hill pit. Ore grade material still exposed in the wall of the Haile pit consists of a highly siliceous and very thinly bedded rock containing minor pyrite. Along strike, the character of the mineralization changes to pyritic massive sulfide lenses occurring interbedded with siliceous horizons at the Red Hill pit. The siliceous rocks vary from the thinly-bedded material as just described from the Haile pit to silicified fragmental-appearing rocks to totally recrystallized cherty rocks lacking any recognizable primary features. Scattered, apparently at random, throughout the very thinly-bedded and very fine-grained ore face of the Haile pit are seemingly anomalous silica-rich clasts or concretions up to 5 cm in diameter which will be discussed later in this paper. Alteration. One of the most striking features of the Haile deposit is the alteration mineral assemblage which is intimately associated with the siliceous and pyritic ores. This altered material has been intersected in drill core at depths greatly exceeding the modern weathering profile and is, therefore, of hydrothermal origin rather than from supergene processes. This "sericite," actually a fine-grained mixture of sericite, kaolinite, and quartz, can be shown to stratigraphically underlie the gold- quartz-pyrite zone, and is well exposed in the open pit just southeast of the Haile and Bumalo pits. Relict textures indicate that this highly altered material was originally a felsic ash flow. Other similar alteration zones have been found in outcrop and drill core underlying the remaining ore bodies. Thus each of the mineralized zones consists of two parts: A siliceous and/or pyritic gold-bearing ore zone which is stratigraphically underlain by a zone of high alumina minerals, in this case sericite and kaolinite along with variable amounts of quartz. A green chrome mica, presumably fuchsite, is present in trace amounts in the high alumina zone. Genesis An adequate model to explain the origin and distribution of the gold deposits in the Carolina slate belt is presently lacking. Worthington and Kiff1 suggested a volcanogenic origin for certain gold deposits in the North Carolina slate belt from the waning exhalations of felsic volcanic piles. They also pointed out that such an origin has similarities to many epithermal precious metal deposits located in more recent volcanic piles in the western United States. A further key to the understanding of the genesis of the gold mineralization at the Haile mine is the close association of the mineralization in siliceous and sulfidic horizons to the genetically related and stratigraphically underlying high alumina alteration. Such high-alumina alteration is common around felsic volcanic centers in the Carolina slate belt and the mineralogy as seen today consists of some combination of kaolinite, sericite, pyrophyllite, kyanite, andalusite or sillimanite depending on the local prevailing grade of metamorphism. Accompanying the high-alumina alteration are large quantities of pyrite and iron-oxide minerals as well as characteristic minor accessory minerals often including base metal sulfides, fluorine-bearing minerals (topaz, fluorite, apatite), titanium-bearing minerals (ilmenite, rutile),

Jan 1, 1981

By B. B. Gottsberger

A NOTABLE feature of the practice of the American mining engineer is the fact that 'his field has been world wide, and the results of his work may be found in all countries. For this reason, the mining engineer is particularly interested in any legislation tending to restrict his freedom in this respect. In their zeal to improve the status of the professional engineer, those responsible for the enactment of the registration laws now in effect in various of the United States may have introduced a practice that will result very much to the detriment of the American mining engineer. He is preeminently interested in the maintenance of the professional "open door," and fame may be the reward of him who calls the first "International Conference for the Limitation of Restrictive Legislation." There is no reason why these United States should be the only country to regulate the practice of professional engineering and, in fact, the movement is spreading beyond its borders. Already, it is necessary for the mining engineer to be thoroughly conversant with the various state laws in order to insure his right to pursue his calling. It may soon be necessary for him to make sure of his status in foreign countries before undertaking work in them.

Jan 1, 1921

By R. B. Roof, J. J. Lombardo

DURING the course of investigations on U-Cb alloys by X-ray diffraction techniques, an impurity or an additional phase was observed in severa1 alloys of various compositions. The X-ray dif-

Jan 1, 1959

By O. P. Chisholm

The most noticeable change in lead smelting over the past few years has been the increase in the smelting rate of lead blast furnaces. For several years a great deal of attention has been paid to the preparation of the blast-furnace sinter charge but more recently the plan has been to incorporate- almost the entire makeup of the blast-furnace charge, excepting coke and scrap iron, at the sintering machines. Formerly, sintering machines were used primarily for removing, sulphur and for agglomerating finely divided material both sulphide and oxide in character. Limestone flux usually was so proportioned that a relatively large amount was added to the furnace charge direct. This procedure was also followed with oxidized ores, which were purposely crushed coarse' so that they would be adaptable for direct smelting on the furnace charge. In later years it has been the tendency in western smelters to include practically all of the limestone and oxidized ores in the sinter charge. This has been somewhat more costly because fine crushing is required for sintering purposes and because these oxidized materials were given additional processing through the sinter plant. The addition of such oxidized materials to the usual charge to be sintered, brought about, in certain instances, a deficiency in heat ordinarily supplied by the sulphide constituents of the charge. This heat deficiency has been remedied by the addition of carbonaceous fuel, in the form of finely crushed coke breeze, or in a few instances by the addition of zinc retort-plant residues. The enhanced gold price has stimulated the mining of crude siliceous ores throughout the Western States and in the smelting of such ores more limestone is required for fluxing. Shipments of gold-bearing pyritic concentrates to Western smelters have increased, and the combination of increased silica, limestone and pyrite has increased the percentage of slag, which, in itself, is an aid in .securing smoother and more rapid smelting in the blast furnace. By the addition of these substances, the percentage of zinc in the slag has been appreciably lowered. at many plants, with resultant benefit to smelting speed at the blast furnace. This increase in slag formation with lowered zinc content has caused also perceptible lessening of the amount of lead on the charge and this has benefited the blast-furnace smelting. Although a satisfactory sinter is fundamental in increased rate of bullion production per furnace, there has been a trend over the list four or five years to decrease the percentage of coke and increase the percentage of scrap iron and limestone on the blast-furnace charge. As a result of these changes in practice certain blast furnaces, without any mechanical change, have doubled or tripled their tonnages. For furnaces whore the volume of air is recorded, records show decidedly larger air volumes with a comparatively small increase in air, pressure, or, none at all.

Jan 1, 1941

By Ed Ramsay

The Kerr Addison process involves the cyanidation, flotation, and roasting of graphitic gold ore. The grinding and treatment section of the present mill has at the present time a capacity of 1400 stpd and the precipitation section has a capacity of 6000 stpd. The grind is maintained at 80%, -200 mesh, and a gold recovery of 92% is obtained in the cyanidation circuit. With flotation and roasting, the overall gold recovery is increased to 98%.

Jan 1, 1978

By W. G. Woolf, A. Y. Bethune

Filtration of hot (60°C) supersaturated zinc sulphate solution (sp gr 1.540) from slimy leach residues at the electrolytic zinc plant of Sullivan Mining Co., Kellogg, Idaho, is described. Separation of liquids and solids in the finished leach is by Burt filters modified to meet conditions of high-acid, high-density process for electrolytic zinc. Operating characteristics of the Burt filter on this pulp are presented.

Jan 5, 1950

By E. D. Meier

SINCE Dr. St. Albans, in 1840, began to build successful watertube boilers—some of which are still in use—the gravity-return water-tube boiler has been built in many forms, more or less familiar to all who have studied the subject. A single firm in this country published recently a pamphlet, showing some fourteen modifications of their boiler during about as many years. There were hence available to the thoughtful inventor of this latest form many data showing what forms were to be avoided, as well as the effects sure to follow certain erroneous methods of construction in the older types. Improvements in materials, tools, and workmanship made possible, forms formerly prohibited by excessive cost. The first Heine boiler was built by A. Borsig & Co., for the

Jan 1, 1886

Jan 1, 1940

By R. A. Bowen

THE Montreal mine, operated by the Montreal Mining Co., is four miles west of Ironwood, Mich., in Iron County, Wisconsin. It is the westernmost producing property on the Gogebic Iron Range of the Lake Superior district. Its production is 4000 tons of hematite per day from an average depth of 2300 ft. This tonnage is hoisted through a five-compartment vertical shaft. Several mining methods are in use but in the larger orebodies the method is sublcvel caving. ORE OCCURRENCE AND CHARATERISTICS The main orebodies of the Montreal mine lie in eastward-pitching troughs formed by the intersections of intrusive dikes with impervious members of the iron formation. The formation has an average width of 425 ft., strikes east and west and dips north at approximately 62°. The dikes dip south at 45° and bear north 20° from the strike of the formation, making the intersections with various members pitch east at 16°. The dikes are not continuous across the formation but are interrupted by a longitudinal bedding fault, which has a throw of 380 ft. vertically and 885 ft. horizontally. North of the fault zone the formation is called "hanging," south it is called " footwall" formation. The faulting has created two ore-bearing horizons; viz., at the inter- section of hanging dikes with the slate members and the foot dikes with the quartzite footwall. In each formation the main ore-bearing member consists of wavy beds of hard chert interlaid with hematite. In the most productive part of the mine, where the sublevel caving method is employed, a hanging-formation dike lies in juxtaposition with a footwall dike and the iron formation carries ore in certain sections from the quartzite footwall to the hanging dike. Here a horizontal section of the orebody may be 300 to 400 ft. wide for a length of 150 ft. or more and tail out lengthwise in both the foot and hanging formations. The footwall ore section is much longer than the hanging wall because of the orebody's greater height above the "pitching dike."

Jan 1, 1938