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By H. R. Coles, S. P. Chong

Test work conducted in the 6.4 and 10.5 m (21 and 34 ft) Aerofall mills at the Iron Ore Co. of Canada Carol project showed that conventionally used "deflector" type liners, which form the basic principle of Aerofall Mill grinding, did not necessarily provide the best grinding performance. A new design, using low profile liners incorporating radial ribs of proper height, actually improved the mill throughput 9-20% without sacrificing grinding efficiency. In addition, the new design reduced liner weight and scrap losses, resulting in a 25% reduction in liner consumption. It provided better protection to the mill shell and reduced the overall maintenance cost for the mills.

Jan 1, 1984

By Robert Stefanko

Roof bolting in coal mines has progressed very rapidly in the last decade, and today this method of support is in general use. There are many theories concerning the functions of roof bolts, but the importance of beam building is indisputable. Proper tension in the bolts minimizes shearing along bedding planes and creates a thick, competent beam from individually weak layers. Bolting must be accomplished immediately upon exposure of the roof, and bolt tension must be maintained if roof failure is to be prevented. Seams are being mined today with roof bolt support where conventional timbering was not effective1. The widespread use of continuous mining equipment was made possible by roof bolts which permit long supported spans free of obstructions.2 Since adequate anchorage is the key to successful bolting, better methods for determining the efficiency of anchorage are continually being sought. Attempts have been made to measure bolt loads, thus assessing anchorage efficiency by employing sensing devices between the bolt head and roof. 3,4,5 None of the techniques appears to be very accurate, and all have at least one serious deficiency.

Jan 5, 1962

By R. W. Culbertson, S. Kasper

During the 1920's, approximately 11,000 small gasifiers were in operation in the United States. They converted about 15 million tons (13.6 Mt) of coal per year into low Btu gas. In some cases, hot raw gas was used for applications such as firing open hearth furnaces or brick kilns. In other cases the gases produced in the gasifiers were cooled, cleaned and desulfurized for various utility and industrial purposes. The steel industry was by far the largest user. The most important fact was that the conversion of coal to a usable fuel gas was demonstrated to be commercial. During the late 1940's and early 1950's, this form of energy was largely replaced by natural gas as the pipeline net work was expanded. Producer gas was no longer economically competitive. Over the past 25 years, government controls on the interstate price of natural gas have maintained this situation. At present only three commercial small coal gasifier plants are still in operation in the United States. These facilities are operated

Jan 1, 1980

The Lead-Line Update held in conjunction with the 1977 SME-AIME Fall Meeting in St. Louis provided sessions on mining, mineral processing, extractive metallurgy, and economies to brief the record on the industry's activities and developments since the 1970 World Symposium on Lead and Line convened, also in St. Louis. Changes in the industry since 1970 have not been profound, notes the program committee, consisting of D. O. Rausch, F. M. Stephens, and B.C. Mariacher, cochairmen; and H. L. Clifford, S. C. Fall), and M. Snedeker. However, various environmental and conservation factors have had a direct impact on process consideration and operating practice; the result has been new mines, improved technology, and changing market opportunities. The general consensus of the participants is that the future for the Lead-zinc industry looks promising as new applications are found and new products resulting from intensive research reach the marketplace. The highlights of the HS technical papers presented at the 1977 session follows.

Jan 11, 1977

By AIME AIME

The Following List Comprises The Names Of Those Persons Elected As Members Or Associates, Who Accepted Election During May And June, 1908 MEMBERS. William H. Bainbridge Searchlight, Nev. William N. Brown, . Gainesville, Va. Willis S. Caypless, .. . . . . Denver, Colo. William B. Clark, Baltimore, Md.

Jan 7, 1908

By Edward Martinez

The literature on the beneficiation of serpentine asbestos ore states that the specific gravity of the rock containing fiber and the fiber itself is the same so that specific gravity cannot be used as a basis for separation. An investigation of particles of asbestos ore ranging in size from 4 mesh to 5 in. revealed that the fiber-bearing particles generally had a lower specific gravity compared to essentially barren particles. The difference in specific gravity was sufficient to make an effective gravity separation of ore particles and reject a low grade tailings product. The results of laboratory tests are described that lead to the running of pilot plant tests with 20-ton ore samples using a heavy media separator. These tests indicated that a large amount of low grade material could be rejected from the raw ore at a coarse size. Although the process used is a wet separation, it can be added to a conventional dry asbestos mill. A gravity preconcentration would allow the mining of lower grade ore, increase the life of the mine, increase the value of the feed to the fiber recovery section, and decrease maintenance costs by removal of low grade tailings early in the flowsheet.

Jan 1, 1975

By R. Adair, W. R. Hudspeth, W. T. McDaniel

A NEW method for concentrating the flake mica either from present washing plant tailings or from new feed has been developed. In this paper, flake mica refers to that which occurs in weathered granites, alaskites, pegmatites, and schists in a form too fine to be considered sheet mica. It ranges in size from 1 in. or more down to 200-mesh or finer and occurs with kaolin, quartz, and partially kaolinized feldspar. Scrap mica, a term often used indiscriminately to describe everything other than sheet mica, will be used to denote the waste product from sheet mica mines and fabricating plants. Both flake and scrap mica are used in the mica grinding plants to produce wet-ground or dry-ground mica, although some flake mica recovered from clay mining operations is fine enough to be marketed without grinding.

Jan 3, 1951

By Leonard Grimshaw

THE idea of bonding two dissimilar ferrous metals, and making use of both, is an old one. Tips have been brazed onto tool shanks for many years. The bonding of larger pieces to form whole bars and sheets has also been accomplished, but has received little attention in the technical literature, although a number of patents have been issued covering various methods for its accomplishment. There are three main motives behind the manufacture of composite steels. One is that the physical properties of one steel may supplement those of another; a useful, but at the same time, hard, brittle steel may be backed by a soft ductile one, or a stainless steel may be backed by a steel possessing greater strength. Another motive is direct lowering of cost; an expensive steel may be backed by a less expensive one, bringing down the cost of the piece as a whole. The third motive is an indirect lowering of cost, as when a useful steel is backed by a steel that is easier to machine, so that machining cost on a finished product is lowered considerably. Often more than one of these motives lead to a decision to use a com-posite steel.

Jan 1, 1936

DURING the early part of August, 1880, I was directed by Prof: J. P. Lesley, State Geologist, to assume charge of the geology and mapping of the Second Geological Survey of the anthracite coal-fields. I visited the region unineumbered by any instructions other than this, that I should submit a plan for making the sur- * In the practical application of this method I wish to acknowledge the valu¬able aid rendered by my assistant, Mr. A. W. Sheafer.

Jan 1, 1881

By W. H. Jr. Meyer

Although an aerial photograph is not a map, most of the information that is necessary for compiling a map is recorded in the photograph provided some form of radial-line method is used to determine the true position of images. The slotted-templet method, which is based on the well-established radial-line principle, has made it possible to construct accurate mosaic maps at a cost comparable with that formerly charged for the average mosaic. It makes possible the securing of these results with far less ground control, which is always expensive. It has expanded widely the possible use of aerial photographs for mapping. ALTHOUGH a vertical or oblique aerial photograph is not a map, most of the information that is necessary for compiling a map is recorded in the photograph. Some ground controls or data are needed, the number and accuracy to be governed by the mapping method to be used and the scale and final accuracy desired in the finished map.

Jan 1, 1939

By W. H. Meyer

Although an aerial photograph is not a map, most of the information that is necessary for compiling a map is recorded in the photograph provided some form of radial-line method is used to determine the true position of images. The slotted- templet method, which is based on the well-established radial-line principle, has made it possible to construct accurate mosaic maps at a cost comparable with that formerly charged for the average mosaic. It makes possible the securing of these results with far less ground control, which is always expensive. It has expanded widely the possible use of aerial photographs for mapping. ALTHOUGH a vertical or oblique aerial photograph is not a map, most of the information that is necessary for compiling a map is recorded in the photograph. Some ground controls or data are needed, the number and accuracy to be governed by the mapping method to be used and the scale and final accuracy desired in the finished map. RADIAL-LINE CONTROL It is essential that the principle of radial-line control in the use of vertical aerial photographs be understood and accepted before any confidence in the slotted-templet method can be gained. A simple sketch and some enlargements showing the Empire State Building will serve to illustrate the cause of displacement of an image that is above the datum plane as recorded in the photograph. The top of the tower of the Empire State Building is directly above the base, and when the image of the top is shown almost two blocks away from the center of the base, it is evident that the image of the top of the tower is not the true location, and in this particular case we know where the true location is; namely, over the center of the base of the tower. If the top of the tower were the top of a hill 1250 ft. high, we would have no way of knowing by inspection the true position of the top of the hill, so it is very important to have a method whereby the true location of any such point can be determined, and thereby make it possible to convert the detail of an aerial photograph into accurate information for mapmaking.

Jan 1, 1939

By Tracy L. Atherton

THE mapping of slant-hole oil fields is complicated by the fact that relationships between wells are subject to variations in three dimensions and are not readily adaptable to representation on a plane surface. Formalized perspectives usually expand into an undecipherable maze of lines and peg models with the necessary supporting dividers serve only to awe the beholder with their perplexity. The usual compromise arrived at is a plotting of the projection of the courses of all of the wells in the field onto a horizontal plane (Fig. I). These complicated plots, when used in conjunction with the individual vertical projections of the wells, heretofore have been the most practical foundation for the study of general field problems. This method has many shortcomings, however, which are not found in the recently developed straight-hole equivalent projection method. The new method supplies a series of maps similar to the type now in common use in straight-hole fields. It is remarkably simple to use and supplies a ready check on clearances between wells. Perhaps the method can best be understood if the steps that led to its development are described. Common practice of oil-well surveyors is to supply the owner with a tabling of the survey and a plan view plotted against the true meridian. If a vertical projection is plotted, it is usually plotted separately and shows vertical depths against the projection of the stations along a section line joining the top and bottom of the hole on the plan view. A more practical method would be to plot the section line of the plan parallel to the abscissa of the vertical projection (Fig. 2). If this is done, any line parallel to the "base line" will pass through the points on each projection that represent a single point in the hole. Another very useful graph, which the well surveyor could provide, would be plotting of vertical depths against measured depths. Fig. 3 illustrates the next step facilitated by this form of plotting. The lines designated "well A" represent the proposed course of a hole to be drilled. Superimposed on the drawing, in its proper relative position, is the plan view and a portion of the vertical projection of a present producer, "well B." From an inspection of the plan view we arrive at the correct conclusion that the only indicated possibility of collision is at the point of crossing of the wells on the plan view. Referring to the vertical projection, note that the vertical depths of stations on B, in the vicinity of the crossing, are plotted on the same plane of projection as A. The clearance is the indicated distance between the two vertical sections measured along the parallel to the "base line," which passes through the point of intersection of the plan view. Repeat this process for the other wells crossing the proposed course of A on the plan view and you have a preliminary check of clearance for the proposed course. A similar comparison of crossings on the vertical projections of all

Jan 1, 1941

By Thomas F. McLoughlin, David K. Hylbert

A new method of satellite imagery analysis has been developed during underground mine roof research. Landsat positive film transparencies were projected onto topographic base maps to scale and lineaments enhanced with a Ronchi grating (method A). Thirty-five millimeter slides of video-enhanced scenes were also projected onto base maps (method B). Both methods permit direct plotting of lineaments to scale and direct correlation with surface and subsurface data wing transparent overlays.

Jan 1, 1981

By Darwin Soler

This chapter will outline the operating procedures at Freeport Kaolin Co.5 kaolin mining operations in Georgia, with emphasis on explaining new techniques recently introduced to reclaim mined-out areas for reforestation. Kaolin is found in the central Georgia area (See Fig. 1) in lenticular, sedimentary deposits of high purity. The beds are Cretaceous in age and vary from 4 to 60 ft in thickness, under a cover of sedimentary overburden ranging from 5 to 150 ft. The kaolin beds contain the mineral kaolinite (a hydrous aluminum silicate) and have a particle-size distribution ranging from about 20µ to the submicron level and averaging about 60% below 2µ. The only contaminants in the deposits are coarse mica, quartz particles, and minor amounts of iron and titanium oxides. These kaolin deposits vary widely in quality from deposit to deposit and also vary within individual deposits. Some of the controlling quality specifications which are determined during exploration are viscosity in water suspension, optical brightness index as measured by reflectance, amenability to bleaching, and particle-size distribution. For this reason, only a small portion of the total kaolin reserves in the Georgia belt are suitable for wet processing for the present markets being served. Kaolin clays are selectively mined by different mechanical methods and are beneficiated by both wet and dry processing to produce a number of products used as fillers and coatings in the paper industry; fillers or additives in the paint, plastic, and rubber industries; and as basic raw materials for the ceramic industry. The State of Georgia is the largest kaolin producer in the United States, with 3,206,454 tons produced in 1966, according to U.S. Bureau of Mines statistics. Freeport Kaolin Co’s processing plant is located in Gordon, Ga., about 20 miles east of Macon, Ga.

Jan 1, 1969

New Mexico School of Mmes, and State Bureau of Mmes and Mineral Resources, Socorro, N. M E. H Wells, President and Director Available publications of the State Bureau of Mines and Mineral Resources of the New Mexico School of Mines are: Bulletin 4, Fluorspar in New Mexico (1928), 60 cents; 5, Geologic

Jan 1, 1933

For the first time in the history of shaft sinking, the concept of mid-shaft loading has been used. By making use of available hoisting capacity during drilling periods, development work on underground hoist chambers and ore-pass and ventilation by-pass systems at Vaal Reefs South gold mine is being done simultaneously with sinking. This factor, together with the unusual configuration and design of the twin-shaft system at Vaal Reefs South, and the use of raise borers in the installation of ore-pass and ventilation by-pass systems, will mean that the shaft will be commissioned at least a year earlier than would have been possible had conventional methods been used. The possibilities of mid-shaft loading in reducing the time normally taken by shaft service development were recognized by Anglo American Corp. consulting engineers and Shaft Sinkers Pty. Ltd., the company which is sinking both shafts at Vaal Reefs.

Jan 1, 1970

A new Military, Engineering School has been established at Camp A. A. Humphreys, Virginia. This camp was used throughout the summer and fall of 1918 for the Engineering Officers Training School in preparing engineer officers for the United States Army. The camp and the courses prescribed were laid out on an ambitious scheme, which since the armistice has been signed, have been directed wholly, toward the permanent establishment of an Engineering Training School for Officers of the regular Army. Those young officers who were graduated from Nest Point at the end of a two-year course, necessitated by the emergency, have been ordered to Camp Humphreys to complete their engineering education.

Jan 3, 1919

By A. M. Gaudin

CHANGES in industrial practice, in plant design, and in research methods which are so clearly to be seen on every hand, have affected the mineral industry as well as others. In particular, ore dressing has passed through a revolution in practice brought about by the introduction of flotation and other quasi-chemical methods, until it has ceased to be solely the mechanical preparation of ores. In fact, the term "ore dressing" itself is obsolescent, and "mineral dressing" has been growing in popularity. This assures adequate recognition of the fact that mineral substances other than ores, e.g. coals, clays, and cement rock, are treated by the same general methods. As a result of these industrial changes it was felt that a complete rearrangement of the curriculum and laboratories at the Massachusetts Institute of Technology would be ad-vantageous. Such a rearrangement would allow instruction and research to proceed in wider accord with industrial evolution and the needs of our times.

Jan 1, 1942

By John B. Knaebel

The annual Jackling Award Lecture, sponsored by the Society of Mining Engineers of AIME, is intended to honor and commemorate one of the greatest mine-makers of all time, an innovator whose vision and determination made ore out of waste rock. He ushered in a new philosophy of mining which revolutionized some segments of the industry and notably affected our economy generally. To have been asked to given the Jackling Lecture this year is an honor that I scarcely deserve, but which I have accepted in humble gratitude. Although it is true that "many a mine has made the man," it is also true that while ore bodies are found, mines are made. That statement has been hammered into my skull many times by a man whose own career exemplifies its truth, a man who has been first and last a steadfast friend, who for a while was my boss and mentor, and who as one of this country's great mining geologists has laid his hand to the making of many a mine. I will doubly cherish the memory of the honor bestowed upon me because the presentation of the Jackling Award was made by this man. After the Lord made Dick Hunt he threw away the mold. Metals and other mineral products are essential ingredients of the social economy of the modern world. No well informed and thoughtful person can doubt that they will be indispensable to mankind as long as the fabric of civilization as we know it today can be held together. They are mined from ore bodies, which, unlike some other kinds of bodies, are physically inorganic and wholly incapable of reproducing themselves. Since in time they become mined out, an endless procession of new producers must be made by someone if the fundamental needs, to say nothing of the not so fundamental whims of an affluent society, are to be gratified. In saying that these mines must be made, I mean exactly that. It is my purpose to comment upon some of the problems we must cope with in making them. I shall try to avoid dwelling needlessly upon aspects of new mine development with which most people in this business are thoroughly familiar, and will attempt to discuss in a useful way some of the newer and more significant features of the economic climate in which these endeavors must be conducted. To begin with, an Almighty force put the ore into the ground, and selected the places in which to put it. Mankind was not consulted. Beyond that stage, however, mankind must find the ore deposits and contrive to extract their contents and put them into useful service. In doing this, he must use tools and techniques devised by man to overcome obstacles created in part by nature, but also in part by man himself. And most importantly of all, in making the tools and applying the techniques, he must use people. In the whole process the most pliable ingredient at hand-and also the most unpredictable-is people. Mines play out, and men die. As time goes on, we will have new mines, and they must be made by new men. The Environmental Dilemma It is perhaps timely to touch first upon the newest and in many ways the most potent consideration affecting the feasibility of developing new mines-the problems related to protection of the environment and to the

Jan 1, 1973

By J. W. Gilbert

DuriNG the sinking of the Needmore shaft, on one of the leases of the Eagle-Picher Mining and Smelting Co north of Webb City, Missouri, a very strong flow of water was encountered at a depth of 140 ft. Because OF the speed at which the water rose in the shaft after pumping was discontinued, and in order to speed up sinking operations, a new type of shaft bar and drilling equiprnent was devised, which saved approximately one hour on each shift This bar is made of an ordinary scren type shaft bar with a common drill arm attached to the bar by clamps and welded Into place To this drill arm is attached an ordinary arm clamp with set collar below Through this clamp is attached another drill bar of ordinary length so constructed that it slides back and forth and rotates around the perimeter of the shaft on the set collar A tripod saddle with legs removed is welded to the rotating bar, which enables the drill operator to drill holes at any angle completely around the shaft and also, after an arm extension, permits the drilling of the corner holes without removal of the rig from the saddle Upon completion of the drilling of a shaft round, all that is necessary for the complete removal of the drill machine and shaft bar is to engage the hoist hook through a. ¾-in. eye provided for that purpose on top of the bar and disconnect the air and water lines from the machine, thereby making it possible to pull the whole apparatus out in one piece. At no time is it necessary to remove the machine from the saddle Screw jacks are installed on the vertical bar to further ensure the rigidity of the shaft and bar arm. The accompanying sketch illustrates the details and method of setting up.

Jan 1, 1946