Search Documents

By E. A. Nesbitt

A new permanent-magnet material has been developed with unusual mechanical as well as magnetic properties. Specimens that have been cast or subjected to a small amount of hot reduction by rolling or swaging may be machined, punched, tapped or drilled. The composition range of the alloys is 30 to 52 per cent iron, 36 to 62 per cent cobalt and 4 to 16 per cent vanadium. After being either quenched, annealed or given the usual cold finishing passes and then heated for 2 hr. at 600°C., such materials have a magnetic energy product of 1.0 X 106 gauss-oersteds. This product is equivalent to that of the well-known Honda steel (36 per cent Co, 4W, 2 Cr, 0.8 C. 0.3 Mn, balance Fe). Material handled in the manner just described does not depend on cold-working for its magnetic properties, and is known as Vicalloy I. The preferred composition for Vicalloy I is 38.5 per cent iron, 52 per cent cobalt and 9.5 per cent vanadium. When the alloys are first hot-worked, then considerably reduced in area by cold-swaging, drawing or groove rolling and then heat-treated, the magnetic energy product measured in the direction of previous extension is increased to 2.0 to 3.5 X 106 gauss-oersteds. These higher values have been obtained only after cold reductions in area of 75 to 95 per cent. Material handled in this manner is known as Vicalloy II and the preferred composi-

Jan 1, 1947

By F. J. Budin

Steel supports are increasingly used in metal mines for junctions, chambers, and other wide openings and for semi-permanent areas such as haulageways, shaft stations, and pump rooms. Steel lasts longer-especially in wet mines and where foul air is present-and is procurable in different sizes that will carry heavier loads than any timber of equivalent cross section. The chief advantage of steel supports is that less excavation is needed than with timber support of the same strength, so that faster progress can be made. Since there is no possible way to calculate the exact weight on supports, sizes must be chosen by experience. Any adjustment and cutting of steel supports underground would be costly and time-consuming, and it is therefore advisable to cut sets beforehand at the surface workshops. This requires standardization of sets. All these problems have been recognized at Bawdwin Mines, Burma, where mining is difficult, slow, and very expensive. The lead-silver ore is very brittle, with hanging and footwall rock of unconsolidated rhyolite tuff. During the rainy season from May to October water penetrates into the mine, and where soft rock is present disintegration into a loose mass around openings can be expected. For this reason heavy 10x10-in. timber caps break quickly in drifts and crosscuts, and timber rots in a very short time. An average increase of 50 pct in both maintenance work and costs could not be avoided.

Jan 3, 1960

By L. K. Jetter, C. J. McHargue

DEVELOPMENT of preferred orientation in uranium is of interest because of the strongly anisotropic properties of the orthorhombic crystal structure. Harris&apos; reported inverse pole figures for rolled uranium rods which showed <010> and <410>* to be parallel to the rolling direction after On 0.19-in. spherical X-ray diffraction specimens taken from the center of the middle section of each rod, pole distribution data were obtained by the spectrometric method described previously.4 The specimen was rotated rapidly about the axis coinciding with the rod axis in order that a large number of grains could be scanned and was rotated slowly about an axis perpendicular to the rod axis. The variation in the diffracted X-ray intensity was recorded as a function of the latter motion (angle 4). Fiber-axis distribution charts (inverse pole figures) were prepared by the method described by Setter, McHargue, and Williams." After having been corrected for background radiation, the pole distribution data (I vs ?) were normalized. A normalizing factor for each plane has been shown to be Iranaom = f I sin 4 ? 4 and was obtained by graphical integration from the data for that plane plotted as I sin ? vs ?. The axis-distribution charts deduced from the normalized pole densities are shown in Figs. 1 to 3. On these charts, the contours indicate angular positions of equal normalized axis density,

Jan 1, 1958

By E. V. Given

In speaking of the concentration of oxidized lead ores at St. Anthony, I do not wish to infer that we believe all lead ores of a similar grade can be mined and treated at a profit. Our oxidized ore is low grade, and certainly the mine under present economic conditions could not operate on this ore by itself. Because of favorable conditions we can operate the oxide circuit at a small profit although we do not allocate overhead, pumping, and certain other general charges to it. Operations in the oxidized zone were started as an essential part of the development necessary to outline and mine the sulphide ores. Nearly all of our oxidized lead ore comes from the Collins section of the mine, with the transition from oxide to sulphide ore lying between the 600 and 700-ft levels. Production from sulphide ore is much larger than from the oxide, both in tonnage handled and in grade of ore. The oxide and sulphide ores are never mixed either in the mine or the mill. The oxide mill sections have their own ore bins, grinding, and flotation departments. The lead minerals contained in the ore, in the order of their importance are cerussite, wulfenite, galena, anglesite, and vanadinite. The ratios of the different lead minerals change as the ore is pulled from different parts of the mine-total lead being approximately 50% to 60% cerussite, 20% wulfenite, 15% galena, zero to 10% anglesite, and 2% vanadinite. About 3% of the lead was unidentified.

Jan 5, 1950

New York, March 18, 1913. MR. CHARLES F. RA ND, President, New YORK, MARCH American Institute of Mining Engineers. Dear Sir: In connection with the official notice of Dr. Raymond&apos;s unanimous election by the Directors as Secretary Emeritus, we wish to place upon record certain statements concerning his services to the Institute which we think have not been published., and may not be generally known to the majority of our fellow-members. When the Institute was formed in 1871, Dr. Raymond acted as Secretary of the Founders&apos; Meeting, and became the first Vice-President of the Institute, and, by request of the aged and beloved David Thomas, who was the first President of the Institute, Dr. Raymond discharged all the duties of the office of President, to which he was later formally elected in 1872, and which lip held for three years. During that time, he visited Europe, and through his acquaintance and reputation abroad, established those international relations of the Institute which proved so important in later years. He also enlisted the support of the mining engineers and metallurgists of the Pacific Slope, who would not otherwise have been disposed to join a society originating in the East. And for twelve years he attended; at his own expense, nearly every meeting of the Institute, wherever held, giving to it without remuneration his best service, and sacrificing for it many professional and private interests.

Jan 4, 1913

By K. C. Lau

INTRODUCTION The design of engineering structures such as mine openings in and foundations on rock requires a knowledge of the constitutive laws governing the behaviour of discontinuous and layered rock masses. At the present time there are two main approaches for predicting the stress distributions and displacements in such engineering structures. In one method, the whole of the rock mass is discretized. The behaviour of the components of the rock mass, that is, the joints and the intact rock are modelled using analytical techniques such as the finite or boundary element methods. Typically the intact rock is modelled as a linear elastic material bounded by non-linear discontinuities. An alternative method of analysis is to describe the load-deformation properties of the jointed, layered or even reinforced rock mass in terms of smeared or equivalent homogeneous material properties. Such equivalent material properties may then be used to compute the stress distributions around openings and in foundations using standard methods of analysis such as the finite or boundary element techniques. Once the stresses have been obtained for the equivalent material, the stresses in the individual constituent layers or discontinuities may then be determined. Each approach to the problem has particular advantages. The first method is more likely to yield results which more closely represent the behaviour of the rock mass, since the behavioural responses of both the joints and intact rock are modelled. However, for many large or complicated geologic structures such an approach can become unweildy and uneconomical. In such cases, the equivalent

Jan 1, 1984

By Eugene McAuliffe

The management of The Union Pacific Coal Co., which operates a group of coal mines in Southern Wyoming, believes in the value of applied psychology as a productive factor in the work of getting out coal. Operating almost wholly through the medium of mechanical loading machinery, the company has for some years paid a bonus, equivalent to one-half the labor saving made above a determined average output per shift worked, on a given machine. No penalty is attached where the established output is not obtained, but in 1933 the men on one class of machines earned an average premium of $0.633 per shift on 56.4 per cent of the tonnage loaded. On another class of machine, the men earned an average premium of $0.686 per shift on 28.4 per cent of the tonnage loaded An increase of 36 per cent in tons loaded per man-shift has resulted since the program was instituted. This coal company has also been very successful in reducing mine accidents through prizes awarded in an unusual way. At the close of the year, every man whose particular mine section passes through the year without a lost-time accident is given a ticket entitling him to participate in a safety drawing where an automobile is awarded as first prim.. There are also a number of cash safety prizes which are similarly awarded. Some 1500 persons attend the drawing, which excites much interest and attention. The particular plan employed, the payment of production bonus awards and safety prizes, is foundationed upon collective. rather than individual effort, and, once gotten under way, has proved to be substantlally self-cnforcing.

Jan 1, 1934

By Gary Mack, Donald E. Scheck

To help management keep key machines or processes at peak efficiency, draglines, shovels and blast hole drills have been equipped with micro- processor based monitors. The dragline and shovel monitors log operating data such as energy consumption, bucket position, cab rotation and the clock time of key elements within each cycle as well as maintenance information. The output consists of maintenance and management data such as the number of cycles, average cycle times, swing angles, depths and downtimes. Extensive experimentation has shown that a blast hole monitor can provide a log of each blast hole in which the hard to fragment zones are indicated. The logs are printed on board the drill and serve as the design basis for decked loading of the holes. As a result, the fragmentation of the overburden has improved markedly with the same or less powder consumption. This material is based upon work supported in part by the Bureau of Mines, Department of the Interior under Grant Numbers G1115006, G1115391 and G5 105006. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the Bureau of Mines, Department of the Interior.

Jan 1, 1983

By P. Martignan

UNTIL quite recently, Alsace was the only district in France where petroleum could be found in somewhat industrial quantities. The Pechelbronn fields produce, however, only about 80,000 tons a year, which represent approximately one-eighth of the domestic consumption. Much research work has been done in Alsace to find the prolongation of the Pechelbronn fields, but instead of oil the drillings revealed the existence of large deposits of potash. This can be easily explained when one remembers that the Pechelbronn oil is of the Oligocene period, and that in the Alsatian stratification the Oligocene lies immediately on the Keuper, i. e., on the strata that originate from a period during which the largest salt and potash deposits were constituted. Before the war, and mostly at the end of the last century, some wells were drilled in. various districts of France where some analogies could be found with the Alsatian geology, the borings being mainly made in the Triassic and Tertiary beds. They led to negative results. After the war, the growing importance of oil urged the necessity of resuming the explorations. But it. is our belief that this was greatly facilitated by the enacting of new legislation, which is embodied in the Mine Act of May 16, 1922.

Jan 3, 1925

By Bjorn Bolviken

Bjorn Bolviken (Geochemist, Geological Survey of Norway, Trondheim, Norway)-Under the heading "Recognition of Anomalies," the author states, "If the frequency distribution is actually log-normal, the probability of these high values being part of the background population is small (less than 0.023 and 0.0013 for 2 and 3 standard deviation, respectively)." The figures quoted seem to be the probabilities of these high values being the mean rather than part of the background population unless "background" is defined as one single concentration. If the background is considered to be a statistical distribution of concentrations,50 (which is probably the case here since the author uses the term "background population"), the probability of any observed value being part of the background may be estimated through a calculation of the number of observed values that are in excess of (or below) the number expected to belong to the background. Apparently, some confusion exists in the literature regarding this point. Many authors accept the concept of background as being a statistical distribution, but do not seem to recognize the consequences of this concept. One of these consequences would be that the background of a chemical element should comprise any concentration between zero and a theoretical maximum, which is governed by the chemistry and mineralogy of the material

Jan 1, 1974

By E. A. Nesbitt

A new permanent-magnet material has been developed with unusual mechanical as well as magnetic properties. Specimens that have been cast or subjected to a small amount of hot reduction by rolling or swaging may be machined, punched, tapped or drilled. The composition range of the alloys is 30 to 52 per cent iron, 36 to 62 per cent cobalt and 4 to 16 per cent vanadium. After being either quenched, annealed or given the usual cold finishing passes and then heated for 2 hr. at 600°C., such materials have a magnetic energy product of 1.0 X 106 gauss-oersteds. This product is equivalent to that of the well-known Honda steel (36 per cent Co, 4W, 2 Cr, 0.8 C. 0.3 Mn, balance Fe). Material handled in the manner just described does not depend on cold-working for its magnetic properties, and is known as Vicalloy I. The preferred composition for Vicalloy I is 38.5 per cent iron, 52 per cent cobalt and 9.5 per cent vanadium. When the alloys are first hot-worked, then considerably reduced in area by cold-swaging, drawing or groove rolling and then heat-treated, the magnetic energy product measured in the direction of previous extension is increased to 2.0 to 3.5 X 106 gauss-oersteds. These higher values have been obtained only after cold reductions in area of 75 to 95 per cent. Material handled in this manner is known as Vicalloy II and the preferred composi-

Jan 1, 1947

By J. J. Bikerman

In a recent study&apos; of the martensitic transformation of Cu-Zn ß-phase alloys, it was noted that the MS temperature at the surface was raised due to the loss of zinc by volatilization. It seems likely, therefore, that the MS temperature may serve as a guide for the measurement of composition. From a knowledge of the dependence of the transformation temperature on composition, 2 it should be possible to detect variations in zinc content which are less than 0.1 at. pct by measuring the MS temperature throughout the sample. It is unlikely that an electron microprobe analysis could detect accurately such small zinc losses because the presently accepted limits of accuracy of the micro-probe analysis in simple ternary systems are of the order of 2 to 5 pct of the amount present.3 In the present study, a composition gradient was produced by precipitating the a primary solid solution, and reheating for a very short time within the 0-phase field. The nominal composition, in atomic percent, of the ternary ß-phase alloy used, 64.2 Cu, 34 Zn, 1.8 Si, was selected because it had an MS temperature of +4°C, thereby simplifying the experi-

Jan 1, 1968

By C Gunther

The purpose of this book is to present the practical side of economic geology concisely and in convenient form; established facts and the applications of accepted views are emphasized; theoretical discussions and questions of genesis are avoided. Coal, iron, and placer deposits are omitted; they are subjects of specialized study that are fully and concisely treated in other works. The reader is assumed to possess a knowledge of mineralogy, petrography, and elementary geology. The arrangement adopted is based on Kemp&apos;s theory of magmatic waters, on Lindgren&apos;s conclusions on hydrothermal and secondary alterations, and on the theories of secondary enrichment enunciated by Emmons and Weed. No general classification of ore deposits is attempted, nor is any attempt made to fill by hypothesis the wide gaps, nor to explain the apparent contradictions that rank economic geology among the most inexact of sciences. The present knowledge of the subject is too incomplete to warrant such broad generalizations. The demand for good properties generally exceeds the supply. While mines of the first rank will undoubtedly be discovered from time to time, it is probably true that a great proportion of deposits having outcrops of commercial grade or of evident promise have been recognized and explored. A review of mining conditions over long periods shows that the rich discoveries belong to pioneer days, and that as time goes on the more important developments are the result of lower working costs, improved metallurgical processes, and an increasing knowledge of economic geology. As engineers in search of developed mines no longer expect to find properties having positive ore of greater net value than the price asked, so those in search of prospects should not expect to

Jan 1, 1932

Jan 1, 1934

By E. T. Dumble

DuriKg explorations made for the Pacific Improvement Company in the early part of this year, deposits of natural coke, of such extent and excellent quality as to be worthy of record, were found in the Santa Clara coal-field. This coal-field lies in the neighborhood of La Barranca, a small town, 95 miles northeast of Ortiz, on the Sonora railway. The coal-beds are exposed in the drainage-basin of Calera creek, which empties into the Yaqui river opposite Toniche; and the old mining town of Turahumari is nearly at the center of the field. Without going into a detailed geological description, it Will be sufficient to say that the entire area is underlain by rocks of Triassic age, much disturbed in places, and cut through and covered by eruptive rocks of various kinds and ages. The coal-beds occur in a series of interbedded sands and clay, in the upper half of the sedimentary Triassic rocks. Below them is a great series of quartzitic sandstoiles and very sandy slates, and above them are other sandstones, and the eruptive member of the group, viz., the Lista Blanca formation&apos;, described in my paper on the " Geology of Sonora," presented at the New York Meeting of February, 1899.* Speaking very broadly, these sands and clays, with their included coal-beds, dip about 30 degrees S.E. This gives their outcropping edses a 3J.E.-S.W. direction. The general dip

Jan 1, 1900

By F. C. Blare

THE best method for the estimation of copper in ores and secondary products is that proposed by Dr. Steinbeck* for the award offered by the Mansfeld&apos;schen Ober-Berg-und Hutten-Direction. It is based upon the decolorization of the blue ammonia solution of copper by potassic cyanide,† It is necessary for the accurate estimation of copper in arsenides that the arsenic be separated from the copper before the ammonia solution is made. The presence of a notable amount of arsenic renders the titration by potassic cyanide inaccurate, the end reaction being obscured by the appearance of a yellowish-green tint towards the end of the titration. The change of the color of the ammonia solution from blue to the tint caused by the presence of arsenic cannot be used for an end reaction, for the intensity and quick appearance of the latter-color depend upon the amount of arsenic present in the solution. In the analysis of speise, the method of separating the copper by an oxidizing and reducing treatment in the muffle, to volatilize the arsenic, gives poor results, and there may easily be some loss of the weighed sample. The separation of the precipitated sulphides of arsenic and copper by treating with sodic sulphide, gives good results, but the process is tedious. I have used the two following methods, which are simpler and more expeditious than those mentioned, with good results. * Fresenius, Zeitschrift Air Anal. Chemie., viii, 1. †First noted by Parkes in the Mining Journal for 1861.

Jan 1, 1881

By Ben E. Lusk

During the past five years, the surface mining industry in Appalachia has launched itself into a technological revolution, which has never been equaled during a similar period of time. Operators have begun to realize that effectively restoring land to a useful purpose, to the satisfaction of all concerned, has to start at the beginning of the operation and be an integrated part of it throughout. In order to insure continued mining in the mountainous areas, with protection of aesthetic beauty, things really have had to change. And so the new steep slope mining theory of "controlled placement" has been developed. Controlled placement is a broad term which means the placement of spoil in steep areas where its condition can be completely stabilized and revegetated. This includes the head of valley fill, mountain top removal, haulback, over the shoulder, block cut, and any other methods where the over-burden is technically delivered, hauled, or compacted, so that there is no adverse after effects when mining has been completed. [(Fig. 1)] Under controlled placement, our whole approach to mining has changed. Before any displacement of soil or uncovering of the coal seam transpires, a complete drainage system

Jan 1, 1977

By Charles Catlett

While the occurrence of phosphorus in coking-coal has assumed less importance with the development of the opeu-hearth method of steel-making, it may not be without interest to note the form in which phosphorus exists in one particular coal-seam. In the examination of what is known as the Big seam, which outcrops a few miles west of Columbiana, Ala., my attention was called to the distribution through the coal, in the form of minute veins and particles, of a resinous-looking substance. A small amount of this was selected, and was provisionally identified as evansite (Al6 Y2 O14, 18 Aq). Subsequently, through the courtesy of Dr. J. Sharshall Grasty, of the Geological Department of the University of Virginia, I was able to secure an additional amount of material, which was purified down to about 0.3 g. This was examined by Prof. John J. Porter, of the University of Cincinnati, and gave the following partial analysis: Per Cent. Loss on ignition,......... 37.43 Phosphoric anhydride,..10.33 Alumina,..........36.33 There was also a trace of silica, and quite a considerable quantity of lime and magnesia. Professor Porter was led to think that the material was not pure, but a mixture of several of the phosphates of aluminum carrying lime and magnesia. The material available did not permit of the convenient determination of the other ingredients. One form in which phosphorus occurs in coal is evidently as a hydrated phosphate of aluminum; and any coal which shows to the eye the occurrence of a light-colored resinous-looking material should be looked on with suspicion as being high in phosphorus.

Jan 1, 1912

A. L. BLOMFIELD, ? Colorado Springs, Colo. (written discussion?).¬I congratulate the author on bringing out a paper of real service to the profession. His contention of uniform size in balls is borne out by my own experience; in coarse crushing at the Golden Cycle in 6 by 6-ft. (1.8 by 1.8-m.) ball-mills we unquestionably gain by screening out the small balls once or twice a month. The point of gaging the ball size to be used by the uniformity of screen sizing is of particular interest. The necessity of sufficient return feed from classifier to the ball-mill is sound and clearly shown. In connection with this, I wish two further points had been gone into as thoroughly: (1) The effect of the quality of classification. In general, it is true that the smaller the per cent. of undersize in the feed the more effective is the mill&apos;s work. This is true on a bucking board, in tube-mills, ball-mills, and grinding pans. Given the possibility of returning. a full-feed load to any mill, it has been my experience that the effective work in the grinder is almost proportional to the quality of the return feed. (2) Again speaking generally, the shorter the tube-mill the greater is the quantity of return feed necessary to keep it loaded. The classification thus keeps the oversize in the mill more free from finished product and thus the crushing more efficient. It is very easy to overload any long mill with too much return

Jan 4, 1919

MIXED emotions were produced by the announcement that the buildup of weapons will be stretched out till mid-1954 instead of the previous 1953 deadline. Reason: government assistance programs will be tougher to get but there will be easement in materials allocations. Earlier in February, DPA had announced that tightening up on regulations governing rapid tax -amortization would become effective March 1. In the future, DPA will have to certify amortization contracts for all construction and permanent installations costing more than $100,000. This action was necessary according to DPA&apos;s James F. King, so that new industrial expansions already approved could be assessed in the light of the changing critical mineral picture. When DMPA inherited the backlog of government assistance, requests from DMA, it moved in fast. The results of DMPA&apos;s work is described in the article on p. 351 by James K. Richardson; The speed with which these requests were approved and the lengthening of the military program have made a reappraisal of the critical mineral list necessary. It looks as though the consumer industries will be getting more metal soon and, led by steel, there is an industry push toward the abandonment of CMP. Relaxing of materials controls appears imminent but discontinuing CMP is in the "let&apos;s talk this thing over" stage.

Jan 1, 1952