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By Henry Hanson

A STUDY of the ore to be treated should be the first step in deciding on a machine for crushing or grinding. Coarse crushing is practically confined to the jaw and the gyratory crushers, the large-size jaw type being often employed in large installations as a primary crusher, followed by the gyratory type for secondary reduction. In small plants where mine-run ore is reduced in a single step, either of these machines will do the work. In intermediate and fine grinding, various machines are used. The relative merit of the different types will be governed in no small measure by the size of the installation, the character of the ore to be reduced and the final product desired for subsequent treatment. It should be possible, nevertheless, with the data available, if properly classified, to arrive at an approximation of the relative efficiency of these intermediate and fine grinders. It should be possible, also, to determine the economic grinding range of the different machines. With this in mind, it will be the object of this article to indicate, in rough outline, how the data available may be classified, rather than to attempt to discuss any particular practice and compare the results with other practices. Conclusions or generalizations can not be drawn without an exhaustive classification of data; in fact, many vital points will have to be determined by additional experiments which can be carried on most advantageously in the laboratory. The expense en-tailed in such experiments would be worth while if the data obtained should lead to definite conclusions that would aid in standardizing and simplifying grinding practice.

Jan 2, 1923

By Edwin Ludlow

IN CONSIDERING the waste in the coal industry, which is the title of this discussion, we must entirely eliminate the anthracite region. The demand for anthracite has been constantly increasing and the mines have been able to run during this last year, while the bituminous field was idle for two-thirds of the time. It is on a 100 per cent. basis, which is the best answer to any waste in industry investigations. The anthracite region is also in a very much better position on account of its control by very large companies which realize that their resources are limited; they must husband these resources in every way and they are making the most careful study of methods of mining and preparation to avoid any possibility of waste. This is well known and realized by the managers of those companies. Even the fine slush which was formerly thrown away is now being stored in the hope that methods will be found by which it can be used economically, either in briquet or pulverized fuel in coking. This has been tried. The anthracite factor may be dismissed from the waste in industry discussion, except as it applies to the general public that burns anthracite; there is a tremen-dous waste of anthracite in the burning of it. Looking at the ash piles where anthracite is burned and seeing the amount of carbon that comes away with the ashes, one realizes that proper efficiency is not obtained in the burning of that coal. Even its higher cost does not seem to bring people to a realization of the necessity of conserving and burning properly the entire coal carbon content of what has cost so large a price. Many people feel that they want to have the coal as large as they can shovel into the furnace; they do not realize that the small coal makes just as many heat units and can be bought at half the price. Consequently, the demand is continually in excess of the probable pro-duction for the larger sizes of anthracite, while the smaller sizes, such as large buckwheat and pea, are a drug on the market and can be bought at nearly half the figure; and yet, if properly burned, these produce just as much heat and can be used with a much greater economy than the large egg and stove.

Jan 3, 1922

By Jan M. Mutmansky

The primary purpose of this presentation is to analyze the strategies available to an operator using either stripping or stripping and subsequent punch mining on a given coal property. The initial concern is the formulation of a mathematical model, which allows an operator to determine and utilize the particular highwall height, which will maximize : (1) Total profit or (2) Profit per unit of operating time. The analysis centers on the relative costs and recoveries involved in a typical coal seam amenable to stripping, augering, and punch mining. The model defines the point to which the high-recovery stripping operation with increasing overburden removal and reclamation costs should proceed before the low-recovery augering and punch mining methods are employed so that the desired objective is achieved. Examples are presented, which exhibit the use of the model on typical operations. Present mining methods as practiced in the Eastern United States are examined in the light of the results. Recommendations for improving present strategies are made and the resulting economic ramifications are analyzed. Particular attention is given to the stripping ratios presently used and recommendations for improving present mining practice are presented. Implications of these recommendations to the design of strip mining equipment are discussed.

Jan 1, 1977

By H. C. Ray

ABOUT the beginning of 1930, coal preparation had reached the stage where the cleaning of coal by liquid or air had become the order of the day. Since that time many new preparation plants have been installed in spite of the years of depression in the coal industry, and this is indicative of a trend wherein the coal producer found it expedient to manufacture a cleaner product in order to compete with other fuels. It was also about 1930 that, because of the difficulties encountered with fine coal in cleaning plants, dust collectors came into use. Both cleaning plants and dust collectors, therefore, were much discussed at the engineering meetings of the early 1930's. During these meetings the many advantages to be gained through the use of dust- collecting systems were pointed out by Hebley,1 Appleyard2 and others. The great possibilities of new markets for this product were emphasized and discussed at the same time; however, the disposal of the collected dust remained a problem. Since the purpose of dust collecting is to improve the preparation and, consequently, the salability of the coal, it seems illogical to return the collected dust to any of the coal being prepared for market use, as is done in preparation plants that include dust-collecting systems. The logical thing is to dispose of the dust in some useful and practical manner outside of the tipple. As a practical matter, this can be done in one or both of two ways; either by consuming the dust at the mine's own power plant or by marketing the dust direct to the consumer. The latter method not only offers the greatest opportunities, but is the most important, because of inequalities that may exist between the quantity of dust collected and the consuming capacity of the mine's power plant. In considering the more important marketing possibilities, we are confronted immediately with the problems connected with the handling and transportation of so fine a material. It is this problem, rather than the problem of finding new markets, that has been responsible for the lack of progress in the matter of dust disposal. It is the purpose of this paper to point out again some of the potential market out- lets, and also to describe an existing system of handling and transporting coal dust. To the best of the writer's knowledge, this is the first and only operation in this country that has handled fine-mesh coal in bulk so-ton lots direct to the consumer. POTENTIAL MARKETS FOR FINE- MESH COAL DUST In general, the potential market outlets would include any operation of which the pulverization of coal is a necessary part. To be more specific, a few of the better known operations of this type must include: colloidal-fuel plants, briquetting plants, “sea coal” distributing plants, water-purification plants and obviously, pow-

Jan 1, 1944

By C. S. Anderson

GEORGIA, since 1829, has produced nearly $18,000,000 from her gold mines, but in late years the output has dwindled to insignificance. In view of present universal efforts to increase gold production, it seems pertinent to record some recent observations in that field, briefly review its past and weigh probabilities of reviving gold mining there. Little in this paper can be claimed as new or original, and it does not present results of a detailed or profound investigation of the whole region. The Allatoona gold mine was reopened in January, 1932, and explored at greater depth during the period from January to June of that year. A number of other abandoned mines were visited, but since the workings, in common with most such mines in Georgia, were flooded or caved, underground conditions could not be examined. For a wider knowl-edge of the subject, a search was made through available pertinent literature and statistics, a bibliography of which is appended hereto. To all the sources obligations are gratefully acknowledged.

Jan 1, 1933

By J. K. Lovrien

A Link-Belt roller-bearing conveyor system was in- stalled recently at the Gross-Marble mine of the Oliver Iron Mining Co. at Marble, Minn., for removal of overburden and lean ore. The material, consisting of clay, sand, gravel, and glacial boulders. is excavated by an electrically operated walking dragline equipped with a 10 cu yd bucket working from a boom approximately 150 ft long. This machine loads into a receiving hopper of a rail-mounted screening plant in 45 second cycles. A manganese steel apron feeder under the receiving hopper delivers to an elliptical grizzly, from which the oversize boulders and extraneous material, by way of an apron conveyor, arc loaded into refuse haulage trucks.

Jan 12, 1951

By R. J. C. Tait

INTRODUCTION Process Control at the Ecstall Concentrator begins in the open pit at the Kidd Creek Mine. While this paper, naturally, emphasizes the instrumental and technical features of the Process Control system within the concentrator itself, it would not be complete without some mention of the selective mining methods and grade control practices at the mine, and of certain features of plant design, which are simple, but highly effective, elements of the Process Control system. The success of the entire Process Control system, from pit to concentrate load-out, owes much to the high degree of cooperation and mutual understanding among all the operating departments at Ecstall Mining Limited and to the willingness of management to accept, from the start, an overall control philosophy based upon the inter-dependence of mining and metallurgical operations. INFLUENCES OF MINERALOGY AND METALLURGY ON MINE PLANNING AND PLANT DESIGN Mineralogically, the Kidd Creek ores are fine grained and mostly very complex. Because of complex mineral associations and extensive inter-locking, very fine grinding and regrinding of middling fractions are necessary and selective flotation requires a very delicate touch. Four separate concentrates are made for shipment to copper, lead and zinc smelters. The Process Control system is tailored to the metallurgical objectives of maximum recoveries of copper, lead, zinc and silver into concentrates of optimum quality, for maximum economic returns. For example, zinc and lead in copper con-

Jan 1, 1970

By Norman Weiss

THE need for more efficient utilization of labor in the metal-mining industry has been the subject of several recent editorials in the mining press, and one attractive possibility for such improvement lies in the designing of future milling plants particularly with economy of man-power in mind. We are accustomed to think of mill design as the selection and coordinated arrangement of process equipment, but if labor is to be efficiently utilized it must be given early consideration in planning the new mill. There are three good reasons for economizing in labor: (I) to reduce costs, not only in the form of wages but also in housing, hospital, welfare, and other obligations that a company accepts when a new man is added to the payroll; (2) to prepare for recurrent periods of manpower shortage, during which a well-designed plant can manage to get along with skeleton crews; (3) because a milling plant that must depend upon an inordinately large labor force for its operation and maintenance is certain to be inefficient in other respects, for many of the shortcomings in design that make necessary the excessive use of labor are generally not corrected merely by having too many men. A simple example of this is a poorly designed ore-feeding system: if this is inadequate to the extent that one man must be constantly unclogging feed chutes, it may help the situation to put two men or three at this task instead of one, but the feed rate will still be inconstant. First of the factors that affect labor saving is the location of the mill. This is often determined by transportation costs alone, and as a result the mill may be placed close to the mine regardless of the nature of the terrain. The designer must then adapt his layout to the conditions, favorable or not. This happens often at small properties, where capital investment may seem more important than operating expense. In most instances, however, a mill site carefully selected for the advantages it gives the designer in laying out the plant is the most economical in the long run, even if it involves a slight increase in cost of ore haulage. Given some freedom of choice, the design engineer may be able to find just the piece of ground that provides the proper gradient for the needs of the flowsheet, permits installation of essential yards and trackage, and perhaps supplies an excellent site for a tailing dam. Further justification for having placed the mill not too close to the mine sometimes emerges only years later as an opportunity to treat ores from other properties. When it is known from the beginning that the new mill will serve a number of scattered mines, a free choice of mill site is naturally stimulated. The most important single factor in limiting the labor requirements of a mill is its materials-handling system for bring-

Jan 1, 1946

By E. R. Force, W. F. Cannon

Many large high-grade manganese deposits occur in marine-transgressive sedimentary sequences deposit fed on stable platforms, although the manganese mineralogy varies from carbonate to oxide facies and host lithologies vary from carbonate- to clay-dominated sections. Examples include the Nikopol and related deposits of the Soviet Union and Groote Eylandt, Australia. Recent work has shown that high sea-level stands are synchronous with stratified and stagnant oceans. We suggest that during transgressions and consequent anoxic events, the anoxic deep waters rich in dissolved manganese were dilute ore-forming fluids. Manganese was precipitated on the oxidized side of oxidation and alkalinity interfaces on shallow shelves. Where the precipitate was preserved, manganese ac- cumulated into ore deposits. Sedimentary manganese deposits have not been widely explored for in North America, nor are they always obvious in outcrop. Large areas of North America are underlain by rocks that we consider broadly favorable for such manganese deposits, and the disparity between the high potential but significant reserves of the United States is difficult to reconcile. Important undiscovered deposits seem likely. An area of Cretaceous rocks in South Dakota is presented as a possible location for a United States deposit analogous to foreign deposits described herein.

Jan 1, 1983

By C. S. Matthews, G. L. Stegemeier

In one field in South Texas, approximately 72 per cent of the pressure build-up results show a characteris-i.rtic "hump" (i.e., the pressure builds up and then falls off) which makes interpretation by. standard methods impossible Correlation of size and time of hump with formation permeability. well productivitv index, and method of completion led to the tentativc, conclusion that the humps were caused by segregation of gas and oil in the wellbore after closing-in"'. This conclusion was confirmed by performance of simple laboratory bubble-rise experiments, by theoretical bubble-rise time calculations, and by a detailed calculation of PVT behavior in the well of a particular well Oil which accurate Surface and bottom-hole pressure measure-ments were untile. The hump behavior has since been found to occur in many other fields. The cause, however, is not the mine in all cases. In some of these the hump is trace-ahie to leaks in the tnbing which allow influx from the annulus after closing-in. In other cases the hump is traceable to leaks in the device separating pay horizons in dually completed wells. It is concluded that the recording of both surface and bottom-hole pressures is desirable in wells which show an anomalous build-up behavior. A number of field examples is discussed where use of both sets of measurements enables the cause for anomalous behavior to he found, (and a reasonable interpreation of bottom-hole pressure to be made. INTRODUCTION Theoretically the pressure build-up in an infinite reser-voir should be a linear function of In [(t + at)/nere t is the production time and At a the closed-in time. Some of the variations from this behavior arc well known, such as the curved portion immediately after shut-in which results from after-production and skin effect, and the flattened end portion which results from boundary effects in a limited reservoir. The effect of stratified producing zones and irregular geometrical drainage patterns may also contribute unusual characteristics to build-ups. However, the effect of still another phenomenon—that of movement of fluids within the wellbore—has been neglected in most build-up studies to date. Fluid movements within the wellbore after shut-in occur as a result of after-production, packer failures, leaks in the casing or tubing, or buoyancy of the gas phase when both gas and liquid are present in the well. Each of these movements can influence the pressure build-up, sometimes sufficiently to negate use of the data for computing permeability or stabilized build-up pressure. Examples of each of these phenomena are discussed below. FIELD OBSERVATIONS ON HUMP BUILD-UPS In approximately 75 per cent of the wells in a medium-sized field in South Texas the pressure build-up curves rise to 3 maximum and then decline to what appears to be a stabilized reservoir pressure as shown in Fig. I. Similar behavior has also been observed in wells in other fields in Texas and Louisian:,. Because of the possibility of such behavior being a mechanical failure of the pressure bomb. the bombs were run in tanden into one well which had been known to exhibit this behavior. When both bombs recorded identical curves with the characteristic hump, it was inferred that the unusual build-up is a result of well or forma-

By C. R. Boyd

It would be a quite congenial task to attempt to describe all that extraordinary mineral wealth which is now giving such prominence to the region from the James River to the Tennessee line: adjacent to the great lines of the Shenandoah Valley and the Norfolk and Western railways; but such a task would be impossible within the limits of any ordinary paper. Hence, in advance of the fifth edition of my book and map on the Resources of Southwest Virginia, I must restrict myself to a limited but most interesting subdivision of this remarkable mineral belt.

Jan 1, 1884

By Robert C. Emmett, Donald A. Dahlstrom

FOR many years gravitational classification has been employed as a basic tool in beneficiation of minerals and coal. While improvements have been made to increase efficiency and fields of application, the basic flow pattern has remained relatively unchanged in most gravitational classifiers. Feed slurry is introduced into a settling pool wherein the coarser solids settle against either an upward or horizontal fluid current, or a combination of both, and are withdrawn in a concentrated underflow stream. The finer solids below the classification point possess too low a settling velocity and thus are primarily swept out through a weir overflow by the bulk of the fluid. Because of its simplicity, efficiency, and low power and maintenance costs, gravitational classification finds a wide acceptance for separations in the range of 20 to 325 mesh.

Jan 10, 1953

By Peter B. Nalle

Over a period of years the Crestmore plant of the Riverside Cement Co. has been supplied with limestone from the Chino limestone bed. The limestone bed dips about 40º and extends 1500 ft along the strike. Thickness of the bed is such that horizontal distance from footwall to hanging wall varies from 400 to 1200 ft. When the new room and pillar mining system was instituted the haulage units used for development were model C Tournarockers. Four of these diesel units were purchased with the idea of using them solely for development work since it was realized that they would have to be supplemented by additional, and perhaps larger haulers.

Jan 4, 1959

By J. J. Taber, W. K. Meyer

Experiments on consolidated sandstones have shown that a variety of conditions are responsible for the wide range of behavior observed when oil and water are displaced simultaneously by a solvent which is miscible with both. The type of displacement is influenced most strongly by the relation between the plait point of the ternary phase diagram and the composition path followed by the system as it achieves mis-cibility. Neglecting viscosity, the displacement becomes less efficient as the distance between the composition path and plait point is increased in either direction so that a very wide spectrum of displacements is possible with different alcohol, oil and brine systems. It is possible by choosing various composition paths as miscibility is achieved to exercise some control over the actual displacement mechanism. Control over the composition path is exercised by adding oil or water in specific amounts to the alcohol prior to its injection into the porous medium. This technique apparently makes it possible to obtain piston-like displacements with systems which are usually characterized by the efficient displacement of only one of the two phases i.e., either oil or water, while the other phase lags behind. However, the simultaneous displacement of oil and water is not as efficient as other miscible displacements at a similar mobility ratio. The evidence indicates that both oil and water "leak" into the alcohol "piston" in compensating amounts. With oils of low viscosities the displacement is inefficient because the low oil saturation in the stabilized bank causes oil to be trapped by water before miscibility is attained. INTRODUCTION The simultaneous displacement of oil and water by solvents such as alcohol has been investigated in the laboratory and in the field. The laboratorv workers investigating all-liquid miscible systems have recognized the great importance that the nature of the traingular phase diagram exerts on the efficiency of the miscible displacement. Gatlin and Slobod pointed out that displacement efficiency will be improved if miscibility can be retained for long periods and that this behavior tends to be followed if the applicable phase diagrams have very low binodal curves. In their unconsolidated sand tests the alcohol was considered an ideal miscible piston displacing both oil and water phases. Later workers have pointed out that an important feature of the phase diagram as far as oil recovery is concerned is the location of the plait point. This is particularly true in the case of consolidated Sandstone.3 Since the original discussion of this effect, the importance of plait-point location has been confirmed and discussed by other author The early workers394 recognized that the position of the plait point could be altered by changing the oil or the alcohol used in an experiment. In addition, recent work has demonstrated that the plait point can be shifted by altering the nature and concentration of dissolved salts in the aqueous phase. However, the entire scope of the relationship between displacement and plait point has not been discussed previously and a technique for changing the composition path as miscibility is achieved in a particular ternary system, i.e., oil, water and solvent, has not been demonstrated. * The importance of oil viscosity on the efficiency of oil displacement by alcohol has not previously been observed, probably because the range of viscosities used in earlier experiments was too restricted. It is the object of this paper to describe the relationships between the ternary phase diagram, fluid properties and the displacement achieved. A technique for controlling the nature of the displacement is also presented. THEORY AND DEFINITIONS PISTON-LIKE THEORY The theory of alcohol flooding has been discussed in some detail.2-4 The concept was advanced that

Jan 1, 1965

By Terry G. Richard, Vernal H. Kenner, Sunder H. Advani

This paper presents and discusses the results of thirty-one fracture toughness tests on Pennsylvanian Age Clay Shale. Two different orientations for this anisotropic material were studied and two series of tests were conducted, namely, 1. a test series to determine the effect of moisture content on fracture toughness, and 2. a test series to study mixed mode fracture. Increased absorbed moisture is found to reduce fracture toughness. Several analyses of mixed mode failure are found to give varying non-conservative predictions of failure stress intensity level.

Jan 1, 1982

By C. F. Smart

Since their comparatively recent development, the alloys of cadmium with silver and copper or nickel, and of cadmium with nickel alone, have been used somewhat extensively as liners for connecting rod bearings and main bearings of internal-combustion engines. In applications where, owing to high bearing loads and elevated operating temperatures, the life of bearings made from tin-base or lead-base alloys has been undesirably short, cadmium alloys have demonstrated considerable advantage. In applications where, because of deflection of the crankshaft or bearing supports, copper-lead bearing metals have resulted in scored shafts, cadmium alloys have been operated successfully. The somewhat serious drawback to these alloys in bearing service has been that they, in common with copper-lead and certain lead alloys, are susceptible to corrosion in the presence of lubricants containing organic acids. These acids may be fatty acids (such as oleic acid) derived from animal or vegetable oils that sometimes have been compounded with engine lubricants, or they may be compounds of an acid nature developed by the oxidation of some petroleum oils under operating conditions. The result of such acid attack on bearings is illustrated by the photograph, Fig. 1. The petroleum oils that are most readily oxidized to a corrosive condition, and the operating conditions under which such oxidation most readily occurs, are now rather well known among the technical organizations of both the petroleum and automotive industries. While means have been developed for inhibiting petroleum oils against such acid formation, the knowledge that this condition may be encountered has been a factor in restricting the wider use of cadmium alloys as engine bearings. It has appeared, therefore, that their value and use would be enhanced if they could be made corrosion-resistant to a degree compatible with the most severe operating requirements. Investigation, undertaken with this in view, indicated that the addition of fractional percentages of the metal indium to the cadmium bearing

Jan 1, 1938

By C. F. Smart

Since their comparatively recent development, the alloys of cadmium with silver and copper or nickel, and of cadmium with nickel alone, have been used somewhat extensively as liners for connecting rod bearings and main bearings of internal-combustion engines. In applications where, owing to high bearing loads and elevated operating temperatures, the life of bearings made from tin-base or lead-base alloys has been undesirably short, cadmium alloys have demonstrated considerable advantage. In applications where, because of deflection of the crankshaft or bearing supports, copper-lead bearing metals have resulted in scored shafts, cadmium alloys have been operated successfully. The somewhat serious drawback to these alloys in bearing service has been that they, in common with copper-lead and certain lead alloys, are susceptible to corrosion in the presence of lubricants containing organic acids. These acids may be fatty acids (such as oleic acid) derived from animal or vegetable oils that sometimes have been compounded with engine lubricants, or they may be compounds of an acid nature developed by the oxidation of some petroleum oils under operating conditions. The result of such acid attack on bearings is illustrated by the photograph, Fig. 1. The petroleum oils that are most readily oxidized to a corrosive condition, and the operating conditions under which such oxidation most readily occurs, are now rather well known among the technical organizations of both the petroleum and automotive industries. While means have been developed for inhibiting petroleum oils against such acid formation, the knowledge that this condition may be encountered has been a factor in restricting the wider use of cadmium alloys as engine bearings. It has appeared, therefore, that their value and use would be enhanced if they could be made corrosion-resistant to a degree compatible with the most severe operating requirements. Investigation, undertaken with this in view, indicated that the addition of fractional percentages of the metal indium to the cadmium bearing

Jan 1, 1938

By E. H. Lancaster, M. E. Mitchell

A MUD-conditioning program found to be very effective for drilling and completion operations on routine field wells requiring relatively short drilling time involves a moderate alkaline-tannate-bentonite treatment resulting in an ultimate filtration rate of 10.0 cc or less (API test). Mud weight schedules are planned from pressure information on completed wells in producing reservoirs and drill-stem test data obtained on other zones not being produced at present. In general, terminal mud viscosities average 45 sec (Marsh). This value has been found to be sufficient to remove cuttings from the well bore on the average well, with the slush pumps in general use on the rigs. On field wells requiring drilling times in excess of approximately 30 days, an alkaline-tannate-lime-bentonite treatment has been effective in maintaining desirable viscosities and filtration rates with a substantial reduction in chemical costs. This system has shown particular advantage on heavily weighted muds and those with abnormal flow-line temperatures. For the most part, the chemical treatment utilized in wildcat drilling follows closely the program used on field wells, depending on depth and duration of drilling operations. Wildcat mud programs are planned from information available from various geologic and operational sources, taking into consideration the possibility of encountering mud problems of a special nature in the wildcat area. Careful planning of wildcat mud pro- grams has proved to have definite value in avoiding most serious mud problems. An analysis and recommended treatment are presented on several special. mud problems which have been encountered in the area in the past. Those problems discussed are lost circulation, blowouts, sloughing shale, excessive chloride contamination, sulphate contamination, and prevention and correction of cement contamination. Introduction Drilling-mud control in the Southwest Texas area, in general, does not involve the multiplicity of problems encountered in other coastal areas. For instance, it is rare that a mixture of problems such as lost circulation, abnormal pressure, severe sloughing shale, and others, occurs on one well within close enough limits in vertical depth not to be taken care of by a sensible casing program, together with a relatively clear-cut mud program. There are conditions such as the fairly widespread occurrence of abnormal pressure in the lower Frio and Vicksburg zones, and the tendency for sloughing shale in the Jackson section which make for rather expensive mud control. However, the availability of fairly accurate geologic and operational information makes possible a reasonable degree of standardization on mud treatment over a relatively large area. It may be said that, over most of this area where drilling is currently in progress, the natural mud made is very poor in quality, but responds readily to moderate chemical treatment to yield very good wall-building characteristics. AS far as field development drilling is concerned, the mud engineer's principal job, once the routine treatment best

Jan 1, 1949

By S. C. Termes, P. E. Richardson, R. L. Wilfong

This paper discusses recent Federal Bureau of Mines research on the selective flocculation of various minerals with insoluble cross-linked starch xanthate (ISX). ISX is insoluble, has a shelf life of more than a year when kept cold, and has a higher molecular weight due to cross-linking than the soluble, non-cross-linked starch xanthate used in previous flocculation studies on nonsulfide minerals. ISX readily flocculates a number of sulfide mineral fines, but no silicious gangue. Floc formation, floc size, and settling rate are dependent on pH. The pH dependence, however, differs for each mineral. Bornite has been selectively flocculated from bornite-quartz mixtures, and the bornite-containing flocs were separated from the unflocculated quartz using decantation and washing procedures.

Jan 1, 1984

By E. De Goyler

Volcanic origin was among the first of the theories advanced to account for the occurrence of the salt domes of the Gulf coastal plain, northern Louisiana, and eastern Texas, and it is still being re-stated in various forms by the most recent contributors to our knowledge of the geology of such deposits. Argument has been largely by analogy and attention has repeatedly been called to the Mexican oil fields, particularly those of the Tampico-Tuxpam region, because of the occurrence of oil in close proximity to volcanic plugs in those fields, an occurrence supposed to have some resemblance to the common occurrence of oil in the salt domes of the United States. The author, having spent several months of the past year in a general study of salt domes and in a detailed study of certain domes in the United States, and having been acquainted for some time with the exploration of similar domes in the Isthmus of Tehuantepec region, Mexico, and with the general geology of the Tampico-Tuxpam region, Mexico, has reviewed the various theories of volcanic origin for salt domes which have been advanced to the present time. The purpose of this paper is to present such review and to discuss the supposed Mexican analogy. Review of Volcanic Theory R. Thomassyl who had visited the Five Islands of Louisiana between 1857 and 1859, in 1860 described them with some care, noting their distinct character, alignment, and similarity, and ascribing to them a volcanic origin. He regarded them as being akin to the mud lumps in the delta of the Mississippi and was impressed by their symmetry and by the ponds or lakes which occur on several of the islands and which he regarded

Jan 1, 1920