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By E. W. Greene, J. B. Duke

This paper deals with the application of froth flotation techniques to the beneficiation of kaolin clay and phosphate slimes, two very fine particle sized materials. The kaolin problem involves the removal of a small amount of a contaminating mineral (anatase), while the phosphate problem involves the concentration and recovery of a much larger percentage of apatite. Due to these differences, and also different response to flotation, the two problems are discussed in separate parts of the article. An idea of what is meant by "Ultrafine Minerals Or Slimes" as used in the title can be had by an examination of Fig. 1. Particle size distributions are presented for a crude kaolin clay, a coarse fraction and a fine fraction. The crude kaolin as mined was blunged with water, degritted through a 325-mesh Tyler screen, and dispersed with sodium silicate. The dispersed crude was then centrifuged in the laboratory into the coarse and fine fractions shown in the figure. The distribution curves were obtained by the well known sedimentation technique of Casa-grande1 using a long arm centrifuge to obtain equiva- lent spherical diameters down to 0.2 p on the finer fraction. Fig. 1 shows the coarse fraction kaolin to be 50% finer than 3 p, while the crude kaolin is 509 f'lner than 1.4 p, and the fine fraction 50% finer than 0.46~. For comparison 53 p on the horizontal scale would represent Stokesian diameters which would just pass a 325-mesh Tyler screen, taking into consideration the Andreasen sieve correction factor of 1.22 times the screen opening. 2 Another helpful comparison is the surface areas, which in square meters per gram, are 0.044 for 53 p particles, 0.77 for 3p, 1.65 for 1.4 p and 5.0 for 0.46 p particles. Fig. 2 is an electron micrograph of a similar fine fraction kaolin showing the hexagonal plate-like particle shapes.

Jan 1, 1962

By Earl Chairman Oliver

The major development in stabilization of the oil industry during 1933 was the transition in the United States from state control to federal control in many of the functions that government is presumed to exercise. A brief review of the influences leading to that transition is given here to suggest its significance and to assist in forecasting its further development. Bitumens were known to the ancients and have been applied to minor uses since earliest historic times, but it was not until after the discovery of oil in considerable quantities near Titusville, Pennsylvania, in 1859 that it was made the basis of extensive commercial undertakings. In 1859 little was known about the origin of oil and gas, the nature of these deposits, and the physical laws that controlled their accumulation. Scientists soon began to study them, but 50 years or more of active oil-field development had elapsed before sufficient geological information had been accumulated to point the way toward efficient recovery of these products. In fact, only within the past five years has the function of reservoir energy become widely understood, yet it is a primary factor in oil recovery. discovery near Titusville, this infant industry has developed into an industrial giant. In complete ignorance of their destructive effect, wasteful development methods were initiated in Oil Creek and these became industrial habits. These habits in turn became oil and gas law. Under that law vast sums of money have been expended, rights have become vested and development methods fastened on a great industry that not only bring upon it periodic demoralization but cause ruthless destruction of the nation's reserves of these important natural resources. This is occurring in the midst of a petroleum era when oil is essential to the nation's security, its industrial supremacy, and the personal convenience of every citizen. Its conservation, therefore, has become a question of grave national concern. Conflict between PHysical Facts and Oil Law This destruction of an important natural resource and periodic demoralization of a vast industry can be halted only by readjusting oil

Jan 1, 1934

By F. J. Norton

THE object of this investigation was to make a comprehensive study of the degassing of molybdenum in order to determine how rigorous a treatment was necessary to completely remove sorbed gases from molybdenum electrodes in vacuum tubes. Some work has also been done with tungsten, nickel and carbon. As a logical development of this work it has been shown that the gas is present throughout the body of the metal and a study has been made of the solubility of nitrogen in molybdenum and tungsten and the rate of diffusion of nitrogen through molybdenum has been calculated. Tests were made on molybdenum from all the commercial sources and no difference was discovered in the nature of the gases present, the amounts or the ease of removal. The reason for this was apparent when a study was made of the manner in which gases are absorbed by gas-free molybdenum. It is necessary to heat molybdenum to 1760° C. in a vacuum of the order of 0.001 micron for a time which varies lineally with the thickness, in order to obtain a condition in which no further gas is evolved by the sample. A sample so degassed can be handled and subsequently assembled in a tube and then degassed readily. The gases obtained from molybdenum are carbon monoxide and nitrogen, the nitrogen being the more difficult to remove.

Jan 1, 1932

It is claimed that the first mining of copper by Americans in Arizona was done at Ajo, near the Mexican border, in 1854,* a year after this region had been added to the United States, under the terms of the Gadsden purchase. A group of adventurers, organized at Los Angeles under the name of the Arizona Mining & Trading Company, came, to the district. This party of prospectors consisted of 20 men, led by Major B. Allen, J. D. Wilson, and William Blanding. † They went first to Yuma, where the party divided, some of them going southward into Mexico while the remainder took the trail to Tinaja Alta, where they heard of the copper deposits of Ajo, which is 85 miles southeast from Yuma.‡ They found attractive outcrops of copper ore, and set to work energetically, but their operations suffered many interruptions, because that part of the country was still controlled by the Mexicans, who were uncertain about the exact position of the new international boundary. The Mexicans tried to expel them, but they held their ground. The first shipment of ore, consisting of native copper and cuprite, came from what is now the western end of of the New Cornelia workings; it was hauled in ox-carts to San Diego, 400 miles across the desert. § Later shipments were hauled to Yuma and floated on barges down the Colorado river to the Gulf of California, whence the ore was loaded on

Jan 1, 1932

By Norman Pilling

The deleterious effect on the mechanical properties of copper, resulting from heating in contact with reducing gases, is well known, but the mechanism of the action does not appear to have been definitely established. The purpose of the present investigation was not to determine the exact variations in physical quality of commercial copper, with its various impurities, as dependent upon the composition of the gas, temperature of exposure, etc., but rather to study the nature of the action and the conditions under which it occurs. The physical result of the so-called "gassing." of copper has been generally described as the development of "brittleness." There appears to be a striking decrease in tensile strength, associated with a considerable loss of ductility, and a small copper strip or wire affected in this way can he snapped in two when bent. Larger articles may have an outer layer alone affected, which can be detached from the core by hammering or bending. Perhaps the earliest reference to this subject is that of Heyn1 in 1900, and among the later observers may be mentioned Archbutt,2 Bengough and Hill,3 Johnson,4 Mathewson and Thalheimer,5 and Ruder .6 Bengough and Hill, while working with arsenical copper, were the first to suggest the possibility of the formation of gases within the copper itself, while Ruder endeavored to explain the action by the reduction of the

Jan 10, 1918

By Wolfram Ruff, H. A. Schwartz

THE spheroidal form of the temper carbon nodules in malleable cast iron and of the graphite mottles of "mottled" cast iron suggests that in both all the graphite in a given mottle or nodule grew from a single center of crystallization or nucleus. ‡ There is, however, a distinct metallographic difference between the mottle and the nodule; the area of mother metal impoverished in combined carbon by the crystallization of graphite in a mottle is practically coextensive with the ramifications of the graphite, while the impoverished zone of metal corresponding to a given nodule is always larger, and usually much larger, than the approximately spherical mass of graphite crystals forming the nodules. Furthermore, the mottle probably is formed during freezing and the nodule almost always at a considerably lower temperature. Assuming that the nodules or mottles can be used as a measure of the existing nuclei (capable of germination) we propose to record certain observations as to the graphitizing reaction in the light of the number and habits of growth of these nuclei. The present authors, in cooperation with others 1-7, have reported upon various cognate aspects of the problem. The fact that temper carbon is a mass of flakes and not a solid granule has become well recognized since the introduction of an improved polishing technique8,9,10 for cast iron. The problem of deriving from the circular planar intercepts

Jan 1, 1935

By Frederick V. Lawrence

Broadly speaking, fluxes are substances which promote wetting and spreading or enhance the fluidity and manipulative properties of materials in joining, fusion, and smelting operations. The term most strictly applies to substances used to facilitate soldering and brazing; but in .he discussion which follows, the definition will be broadened to include materials used to promote fusion in arc welding and which aid in he smelting of metals. In each of the mentioned applications, the role of flux and its composition differs considerably; consequently n the discussion which follows, fluxes for soldering, brazing, arc welding, and smelting applications will be considered separately. Soldering and Brazing Fluxes Soldering and brazing are metallurgical joining processes in which a joint is formed using a filler metal of composition dissimilar to that of he joined pieces (base metal). The filler metal, older or braze, is always of lower melting point than the base metal. Consequently with these) recesses there is no melting of the base metal. The successful creation of the joint depends upon the wetting and spreading of the solder or braze around or throughout the joint. The obstacles to successful soldering and brazing are contaminants and tenacious oxide films on the metal surfaces. In soldering and brazing applications, fluxes act to remove and exclude oxides and other impurities from the joint. There is no fundamental difference between soldering and brazing. The distinction between them is made on the basis of temperature. Joining operations carried out at temperatures above 500°C are termed brazing. The higher temperatures used in brazing enable higher melting point filler metals to be used which generally provide stronger joints. The higher temperatures of brazing processes also require fluxes which are substantially different from those used in soldering and which will remain effective at high temperatures. Consequently the distinction between soldering and brazing can also be made on the basis of the fluxes used.

Jan 1, 1975

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 Joseph N. Morrison

A comprehensive solution is offered to the problem of dust emissions at belt conveyor transfer points. Details of enclosure design are discussed and a straightforward procedure for calculating required dust control exhaust volume is presented. Many design variables are taken into account which heretofore have been commonly ignored or inadequately considered. These include belt widths, belt speeds. enclosure openings, material flow rate, material bulk densities, material lump sizes, height of material fall, material temperature, and ambient air temperature. All of these questions are handled by means of a "fill-in-the-blanks" type of calculation form, permitting quick, reliable solutions by relative "non-experts."

Jan 1, 1972

By John G. Cazort

In August 1957, a cutter suction dredge started the removal of overburden from a bauxite deposit near Paranam, Surinam (formerly Dutch Guiana), South America. This event marked the climax of a program of investigation, design and construction which lasted almost five years. Cutter-suction dredges are used predominantly for harbor and river work, and land reclamation. While they have been utilized to remove overburden from ore bodies, notably at Steep Rock, Ontario, and Black Lake, Quebec, the conditions under which one is being used for this purpose in Surinam are unusual. Paranam is a mining town built by Suriname Aluminum Company, a subsidiary of Aluminum Company of America. It is located on the Surinam River, about 30 miles from the Atlantic Ocean. The bauxite mining, drying and shiploading facilities have been in operation since 1941.

Jan 10, 1960

By R. M. Brick

A PREVIOUS publication 1§ has described the effect of quenching stresses on the lattice parameter values of high-purity aluminum-copper alloys particularly with reference to the solution and precipitation of CuAl2. A similar study has been made of the aluminum-rich aluminum-mag-nesium alloys. Attention has been directed in the present investigation to the magnitude of the quenching stresses as affected by the specimen size and shape, the number of solute atoms and the quenching rate. The effect of cooling stresses in causing plastic deformation or cracking has been considered in relation to the physical properties of the alloy. On reheating alloys in the two-phase field, the time required for pre-cipitation to occur has been observed in connection with the degree of supersaturation, the rate of diffusion of the solute atoms as a function of the comparative atomic radii, degree of strain, temperature of reheating and grain size. A few qualitative comparisons on the relative effect of these factors have been drawn between the aluminum-copper alloys and the aluminum-magnesium alloys.

Jan 1, 1935

By James J. Bailey

Percussive drills have been in commercial use for many decades. Until relatively recently there was little serious effort to analyze the stresses in such devices in any detail. Within the last few years such analyses have been developed and have been reported by a number of authors.1-4 We present here an investigation of the impact systems of a family of conventional down-hole drills with optimization the objective. We have assumed that maximum drilling speed was the quality most desired and that this was to be achieved within conventional practice. In fact the methods that are demonstrated in principle below can readily be adapted to other percussive devices, whether conventional or not, and to other constraints. SOME PERFORMANCE PARAMETERS FOR PERCUSSIVE DRILLS Consider a percussive drill with an air motor operating with the following parameters: p-supply air pressure a-effective piston area W-piston mass S-piston stroke If we consider a simple (constant pressure) cycle, the following relationships can be derived. The blow frequency [N~ pa lie WS 377]

Jan 1, 1968

By R. F. Weber

The relation between the chemical composition and the refractoriness of fire-brick has long attracted the attention of manufacturers of fire-brick and others interested in their use, yet but little systematic work has been done along this line, especially in the United States. Analyses of fire-brick have been quoted for years, but fire-tests of brick, except those of durability in practical use, have usually been lacking. Although many tests and analyses of foreign fire-brick have been published, only a few have appeared in the United States; and even in the foreign literature, the references and facts are more or less scattered. The most elaborate foreign paper on the subject is that by Dr. Jochum.' One of the earliest, and perhaps the most detailed piece of work in the United States, is that of F. Platt, which was done for the Pennsylvania Geological Survey, in 1876.2 His investigation consisted of the analysis and heat-tests of 21 bricks, the testing being made in an experimental shaft-furnace at Har-risburg, Pa. All the bricks were more or less affected at the temperature reached, which was considerably higher than the melting-point of steel. The exact temperature at which individual bricks fused was not ascertained, hence the comparisons quoted in the paper are of value only for the bricks used in the test. The next comprehensive investigation, made by the New Jersey Geological Survey,³ deals chiefly with fire-clays; analyses and refractory tests having been made of 123 clays, kaolins, feldspars and fire-sands. Here; again, there was no accurate means of measuring the temperature, the only measurement of

Jan 1, 1905

By N. Malakouti, R. H. Whipp, O. A. Kuby, R. M. Smailer

A detailed description of the development of the FIOR process (Brown, Campbell, and Saxon, 1966) and, subsequently, other technical papers related to the operation and start up of the FIOR plant (Violetta, 1975; Whipp, 1980) are available in the technical literature. The Fluidized Iron Ore Reduction (FIOR) process plant constructed in the Matanzas region of Venezuela represents the first commercial application of this technology. The FIOR process was developed by Exxon Co. during the 1950s and 1960s. The facility in Venezuela was designed and constructed by Davy McKee, with plant start-up in 1976. While there is a minority government ownership in the company, FIOR de Venezuela operates as a private sector company with the majority of ownership being private capital. The FIOR process is well suited to utilize the naturally occurring iron ore fines of the Cerro Bolivar and San Isidro iron ore deposits located less than 100 km (62 miles) south of the plant site. Availability of natural gas within 150 km (93 miles) to the north, and a location bordering on the confluence of the Caroni and the Orinoco Rivers makes for an ideal geographic site. Feed stock to the FIOR plant consists of naturally occurring iron ore fines from these ore bodies, which are screened to -6mm (-0.2 in.) prior to drying in the ore preparation plant. A simplified flow plan is shown in [Fig. 1]. The dried ore is then transferred to the top of a structure containing four fluid-bed reactors located above one another so the mineral may flow from one reactor to the next by gravity. A reducing gas containing 90% hydrogen is made by steam reforming of natural gas, a CO shift

Jan 1, 1983

The phosphate pebble-bearing matrix in the Florida Phosphate Pebble Field has physical properties which make it readily adaptable to hydraulic transportation methods employing solids-handling pumps and pipelines. The abundance of water available, a practically flat terrain, low costs per ton-mile, and beneficiation of the matrix by agitation while being pumped have contributed to the popular choice of hydraulic transportation. Phosphate pebble mining in Florida, begun in the 1860's, first used high pressure water and solids-handling pumps for overburden removal about 1900. Removal of the average 25 ft of overburden was followed by hydraulic mining of the matrix, with 6-in. and 8-in. pumps handling 50 to 100 cu yds per hour being moved along the floor of the pit as they were advanced toward the face being undercut and slurried by hydraulic guns.

Jan 3, 1961

By S. M. Matthews, D. J. Maconochie, L. G. Alexander, V. H. Tillmann

Case studies of the behaviour of large open stopes at the New Broken Hill Consolidated Mine, Broken Hill and the CSA Mine, Cobar, N.S.W. are considered. Deformations were measured by multipoint rod extensometers in sufficient detail to note the phases of rock behaviour, from intact through to rock-fall. In one case readings were obtained from a zone of stress failure in which two bumps, felt as ground tremors, occurred. In this case noise and stress were also monitored. Deformations were analysed in relation to previously measured in situ rock stress, and conclusions drawn about the degree of conformity to, and the areas of departure from, elastic model behaviour. Attempts to describe the growth of instability utilize reduction factors of the apparent modulus, a magnification factor for the apparent Poisson's ratio, and a correlation between progressive noise count and displacement. Monitoring itself is seen as an aid in determiing the final dimensions of stopes and pillars. One large stope, of intermediate dimension 80 m, was mined essentially without change of plan, whereas a change in mining plan was necessary in other stopes. Aspects of interest to mine planners, and areas where futher research is needed, are indicated.

Jan 1, 1981

By Morris M. Fine, Norwood B. Melcher

As a raw material, prereduced pellets can be considered symptomatic of the quiet revolution taking place in the quality and grade of blast furnace burdens for the past decade. In 1954, the average analysis of ores from U.S. ranges in the Great Lakes area was 50.86% Fe (natural), 10.22% SiO2, and 10.90% moisture; ten years later, the average was 56.67% Fe (natural), 8.13% SiO2, and 6.17% moisture. The advance in Canada was even more pronounced in a lesser number of years. In 1957 the average product of Canadian ore-producing areas was 51.62% Fe (natural), 8.59% Si02, and 8.02% moisture; in 1964, the average grade was 59.59% Fe (natural), 6.27% SiO2, and 3.94% moisture.2 These dramatic data are testimony to the giant strides made in iron ore improvement, and the next logical step is prereduction. Prereduction can well be considered as a beneficiation step in which oxygen is the gangue. Since the ultimate objective of milling and smelting is iron metal, non-metallic constitutents in general, whether oxygen or silica, are contaminants. The past and continuing attack aimed at lowering the silica content of concentrates is succeeding. One need only thumb through the Grade Name listings of the American Iron Ore AssociationVo note that virtually all commercial pellets contain less than 8% silica, many are lower than 6%, and a few below 45%. With natural technical evolution, it is expected "many" rather than "few" will ultimately be in the last category and further mechanical concentration will have reached the point of diminishing returns. At this level, oxygen would constitute the only major diluent worthy of attack.

Jan 7, 1966

By Francis B. Foley

From the point of view of the metallographist, the adaptation of x-rays to the study of the crystal structure of metals is of the greatest importance. While one may hardly consider the findings resulting from x-ray study as revolutionary, their positive nature, compared with the deductions we have been forced to accept from the work that had gone before, gives firmer ground on which to build and furnishes new fields for speculation. Prior to the advent of the crystallogram, the best work on the crystal structure of steel was that of Osmond and Cartaud.' They concluded, from their investigation with percussion figures formed at various temperatures, that alpha, beta, and gamma irons belonged to the cubic system and that they showed well-marked specific characteristics and could not have the same internal structure. What the internal structures were, they had no direct method of determining; but from a consideration of the fact that the 001 plane (that parallel to the cube face) is a plane of perfect cleavage and minimum hardness in alpha iron and that the 111 (octahedral) plane is by far the most important in the crystallography of gamma iron, they were led to suggest the simple cubic arrangement as that of alpha and the face-centered cubic arrangement as that of gamma iron. They suggested the body-centered cubic arrangement as that of beta iron. The atomic arrangement of the various crystal forms of iron has been quite definitely determined in recent years by means of x-rays and the work of Westgren2 and Weatgren and Phragmen3 has been rather conclusive. They not only determined the atomic arrangement of alpha, beta, and gamma iron but also that of the high-temperature modification delta.

Jan 1, 1926

By Milton H. Ward

This paper contains a review and discussion of the major design parameters of a block caving mine, with special attention given to access, development, and operational methods. Information will be provided on the economics and costs of various design alternatives, and how they can influence financial results of a particular project. Technical and economic factors that pertain to an actual operation, Freeport Indonesia, Incorporated's block caving mine in Indonesia, will be provided, and highlights of the planning, development and operation of this mine will be presented. The major thrust of the paper will be to emphasize the importance of good planning and to encourage economic analysis of various methods of layout and design.

Jan 1, 1981

By W. H. Emmons

A DIATREME is a hole blown through a rock by gases, presumably of volcanic origin. Not all pipes of ore have formed by deposition of metals in such openings, but a considerable number have so formed. In this paper are described peculiar vein patterns that are believed to be incipient diatremes or "perforation pipes." Grading into this group is one showing thorough brecciation without rotation of fragments and into the latter a group of ore pipes showing brecciation with rotation of fragments-many of them with well rounded fragments. Also, volcanic craters or volcanic necks are explosion pipes. These may carry ore deposits along their contacts and some carry deposits within the pipes. As new data appear this group becomes increasingly impressive. It has been shown that veins are concentrated in and about cupolas of batholiths and that such veins commonly lienearly parallel to the long axes of cupolas as these are shown on plans. It would be supposed that conical cupolas would have radial patterns, but few vein systems exhibit radial patterns. It is probable that explosion pipes also may form in areas above conical cupolas. From these the gases escape more violently because the loads above them are less than above an elongated cupola where larger bodies of rock are affected. The hypothesis is sound mechanically, for the top of an elongated cupola is a line whereas the top of a conical cupola is a point.

Jan 1, 1938