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By H. H. Einstein

Swelling ground is one of the most feared problems in tunneling. Although usually not causing sudden failures during construction, the very large and longlasting deformations give contractors and designers the impression of facing an inevitable phenomenon against which there is no technical defense. Examples are concrete liners up to 1 m (3 ft) thickness that have been cracked or crushed, tunnel inverts that are heaving at 0.1 m (0.3 ft) per week during construction and continue to heave during decades. This paper summarizes essential components of design construction procedures where tunnels in swelling rock can be built to perform satisfactorily. It is important to point out that design and construction cannot and should not be separated. The way the tunnel will be built has to be an integral part of the design. Swelling can be defined as time dependent volume increase and is distinguished from squeezing, another time dependent phenomenon occurring in tunneling. Squeezing involves exceeding the shearing resistance while swelling usually does not. Swelling of rock masses can occur as swelling of the intact rock, swelling of wall rock, of gouge and of filler in the discontinuities of a rock mass, and as a combination of the above. Swelling mechanisms have been discussed elsewhere (ISRM 1983).

Jan 1, 1984

By F. L. Wolf

THE reclaiming of metallics from slag and sweepings is of vital interest to every brass-foundry man, but the first cost and interest on the investment often make it prohibitive for the small foundry to enjoy the benefits of a complete concentrating unit. However, the cost of such an installation and the cost of operation are often exaggerated to such an extent that foundries dispose of their copper-bearing refuse at a great loss. This paper gives the actual costs and the returns obtained in the reclaiming plant used at the Ohio Brass Co. This plant is divided into two sections, the preliminary treatment and concentrating departments. In the former occur the screening, crushing, and hand-picking operations whereby most of the non-valuable and heavy metallic constituents are removed. The concentrating equipment consists of an elevator, bins, jigs, ball-mill, and table. PRELIMINARY TREATMENT The preliminary treatment varies, depending on whether the material is slag, foundry-floor sweepings, or brass casting-floor sweepings. Material of the first class is produced from the operation of six Steele-Harvey and six Schwartz furnaces; the second class represents sweepings from an average of thirty-five molding floors per day; and the last is collected around the sprue cutters. and knockout bench.

Jan 9, 1920

IT has been discovered by skilled bell founders, more through experience than from geometrical calculation (although calculation does enter), that a certain relationship of dimensions in both large and small bells makes the tone and the weight almost certainly what is desired. This is in addition to the customary shape which is, according to the historians, perhaps that found by the first discoverers of bells. Among themselves bell founders have made a rule of these measurements and have called it the bell scale. Beginning with the small ones weighing ten pounds, it increases by degrees to a point where, as I have seen, they are able to make them even twenty-five and thirty thousand pounds. This scale is of great enlightenment if one does not have a bell already made for comparison.

Jan 1, 1942

By Roderick K. Davey

Introduction in any business, it is essential that we select those alternatives which are not only technically feasible, but will be the most profitable to the business m terms of corporate objectives Some of the studies and activities requiring support of financial analysis to select the alternatives which most closely satisfy the management objectives and technical considerations are as follows 1 ) Cutoff grade determination. 2) Ore reserve estimation. 3) Production forecasts (long- and short-term) for an operating mine, development of a new mine, or expansion of an existing mine. 4) Evaluation of haulage alternatives. 5) Evaluation of equipment.

Jan 1, 1979

By Frank Ittner

In this section it is proposed to discuss operating methods considered good practice under the various field conditions commonly encountered. Efficient field direction and types of equipment needed to meet transportation problems are considered only to the extent that the desire to produce the best possible records must sometimes give way to the factor of cost. As in all engineering projects, alternative possible methods of operation must be considered in the light of relative costs as well as of the quality of results obtained, Cost may be in the background of much that is done in the field operations, but only the effect on record quality will be considered here. Record quality at a particular shot point may vary with the various factors of spread character (relative positions of geophones and shot point), shot-hole depth, formations opposite position of shot, size of charge, the effect of repeat shots, surface geology and culture in the immediate vicinity of the geophones, recorder instrument characteristics, particularly filter.

Jan 1, 1940

Thus far virtually the sole theme of the conservationist has been the preservation of natural resources. Little thought has been devoted to the conservation of America's most significant asset-her people. True, considerable effort has been devoted to conserving man's physical strength by the invention and application of labor-saving machinery. Notable progress has been made also in the conservation of man's health through important discoveries in medicine. However, little if any positive success has been achieved in the conservation of the most valuable attributes of man-intellect, skills, manpower. Human resources are interrelated and interdependent. There is no monopoly on knowledge or skills' or human energy. No one must sell them short. All the knowledge and all the skills and all the energy possessed by all men are required to render all the services needed by all men. One of the major sources of wasted manpower is found in the nation's schools, with an educational system based on the outmoded theory of uniform education for all. Actually, if democracy means free initiative for the individual, and unlimited progress at the maximum rate of speed of which the individual is capable, then our public schools are not democratic in-

Jan 1, 1950

INTRODUCTION Much discussion has been generated over the years among geologists and engineers as to the ideal drill-hole configuration and spacing for evaluating various types of mineral deposits. Little can be found in the literature about the outcome of the programs, probably because of their subjective nature and the then lack of suitable means of scientific testing. In years past the drilling patterns and sequence were almost entirely determined by the experience and personal bias of the senior engineer, geologist, or project manager on the job. However, planning a drilling program- spacing, pattern, sequencing, etc.-is simply a specific case of sample design, or the design of a sampling program. Having been exposed in the preceding chapter to the theory of regionalized variables, and having learned something about the tools for measuring correlation, or lack of correlation, among samples within a given mineralogical population, we are now prepared to apply these concepts and new-found parameters to a scientifically designed mineral sampling program, be it by drilling or other means. FACTORS IN SAMPLING DESIGN It was shown in Chapter 8 that three major factors should be considered in any mineral

Jan 1, 1980

By Edwin A. Sperry

In 1892 I tested an ore, which was peculiarly difficult to treat, on several concentrators then in general use, including t,he Frue-vanner, the Luhrig table and the Cornish buddle. Owing to the character of the ore it had to be crushed- to a very fine state of division, and the results obtained were far from satisfactory; a large proportion of the values was lost in the slimes, which indicated the necessity of a very careful sizing before dressing. Even after reworking some of the slime-tailings, the results, in my opinion, were not as good aa those which might be obtained on a table designed more especially for the handling of slime. Although the subject of slime-concentration has occupied the attention of many engineers who have threshed the field quite thoroughly, the results obtained in my work led to a careful

Jan 1, 1904

By O. P. Arora, J. B. Darby, Paul A. Beck

LAVES and Wallbaum' reported that the phases occurring at the compositions TiFe, TiRu, and TiOs, which are stable over a wide range of temperatures and are separated from neighboring phases by wide two phase fields, have a CsC1-type ordered structure. For TiRu and TiOs, this was recently confirmed by C. B. Jordan.2 Recent results of Greenfield and Beck3 show that solid solutions with ruthenium of the body-centered-cubic elements vanadium and tantalum (and presumably also of colum-bium) in group Va of the periodic table undergo CsC1-type ordering. Although detailed phase diagrams for these systems are not yet available, it would appear that these ordered structures are separated from the neighboring body-centered-cubic solid solutions by relatively narrow two phase fields.

Jan 1, 1957

By J. B. Hiskey, W. J. Schlitt, W. G. Pitt

Aqueous SO2 (sulfurous acid) is an interesting chemical compound. It functions as a reagent in various hydrometallurgical systems, but also represents an undesirable constituent in gyro- and hydrometallurgical effluent solutions. When present in such streams, SO2 can be oxidized to the more stable sulfate form to avoid exsolution of SO2 as a source of fugitive emissions and to simplify standard water treatment plant operation. This study provides information on the stoichiometry, kinetics, and mechanism of SO2 oxidation using oxygen and an iron salt catalyst with solutions containing 0.05-20 g/L (0.002-0.7 oz per gal) SO2. The effects of iron salt concentration, oxygen pressure, temperature, degree of agitation, and pH on SO2 oxidation are also described.

Jan 1, 1984

By J. A. Herbst, J. L. Sepulveda, J. D. Miller

Abstract-Lead cake, a zinc smelter flue dust residue, consists primarily of lead sulfate. Characteristic properties of lead cake were determined in order to aid the understanding of reaction mechanisms involved in bismuth removal from lead cake by sulfuric acid digestion. Sp gr (specific gravity) measurements, surface area measurements, and photomicrographs revealed that the particles of lead cake are quite porous and seem to consist of an agglomeration of submicron grains (0.4 pm) fused together in a manner similar to cement clinker. Analysis of experimental rate data, which was independent of particle size, indicates that the dissolution reaction involves two distinct, rate limiting steps. The initial stage of reaction appears to be limited mainly by intergranular diffusion of the reactant, hydrogen ion, while the latter stage of reaction appears to be controlled by diffusion of soluble reaction products through the reaction product layer of the individual grains.

Jan 4, 1978

By O. L. Kowalke

During the last few years the use of base-metal thermocouples has increased very considerably in various industries, due to the necessity for more precise control of temperatures. The base-metal couple has the advantages of being robust to a surprising degree, cheap as compared with platinum couples, sufficiently accurate for most operations, rapid in indicating changes in temperature, easily renewed or repaired, and of generating a much higher electromotive force than the noble-metal couples. There are, however, some factors, such as indicating and recording instruments, the insulation on the elements, the constancy and homogeneity of the wires, and the resistance to oxidation in the furnace, that limit the. Usefulness of the temperature-measuring device. It is the purpose of this paper to discuss in what manner these factors affect the usefulness of the couples.

Jan 9, 1919

By A. S. Appleton

The diffusion of carbon in Fe-Co-C austenites was studied as a function of cobalt concentration up to 12 at. pet, using an autoradiographic technique. The diffusion coefficient was found to initially decrease and then increase with increasing cobalt concentration, the trends being more marked the higher the temperature of diffusion. These effects were paralleled by variations in the activation energy and the constant for diffusion which, however, were found to be dependent also on the carbon content. The results are compared with the previously available data and their significance is discussed in terms of the kinetics of solid-state reactions in this systern. THE influence of cobalt on the diffusivity of carbon in austenite was first studied by Smoluchowski,' his data being that most commonly cited in works

Jan 1, 1964

The income of the Institute is derived mainly from dues, advertising in MINING AND METALLURGY and sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion constituting endowments for especial purposes. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd Memorial Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization.

Jan 1, 1938

By Archibald Blue

JUST one hundred years ago, in a paper read before the Royal Society of London and published in its Transactions, Rt. Hon. Charles Greville established and named the mineral species, corundum, the crystalline oxide of aluminum; and we have it on the authority of Professor Judd that in an appendix to Greville's paper the Count de Bournon correctly defined the crystallographic characters of the species. The names of its

Jan 1, 1899

By S. Chander, V. N. Sharma

Nickeliferous laterite ore from Sukinda, Orissa (India), consists of very fine particles agglomerated into larger aggregates. The ore is chemically and mineralogically complex and presents many characterization and beneficiation problems. In this study the results of a detailed investigation to characterize the ore by several techniques are discussed. Various techniques used for characterisation include elemental analysis, electron microscopy, electronspectroscopy for chemical analysis, x-ray and electron diffraction, differential thermal and thermogravimetric analyses, EDAX analysis, Mössbauer and infrared spectroscopy. Generally one method compliments the other and it is shown that a combination of several techniques is necessary to fully characterize the ore. The scope and limitations of the techniques are also discussed.

Jan 1, 1980

By H. L. Washburn, W. A. McConnell

There is not a coal preparation engineer alive who would equip his newest and most modern preparation plant with all new and untried pieces of equipment. He may install a few such pieces in which he has great confidence, but he will also spend much time assuring himself that everything else in the plant has been subjected to the test of time. He may arrange these units in a unique manner, but in general, they must have proven themselves elsewhere before he will approve them for his plant. A modern coal preparation plant contains only a few items of processing equipment, the remaining items being devices for materials handling. Consequently, pure automation is almost impossible. Although the main aim of automation is conservation of manpower, it generally results in uniformity of product, lower maintenance costs, and the many intangibles that make a better plant.

Jan 8, 1961

By Paul K. Krueger

SUMMARY Since 1970 the Federal Preparedness Agency has been using computer models to help establish the amounts of strategic and critical materials to be held in the National Stockpile. Fifty-three of these materials are metals or minerals. The following diagram shows the linkage of models used to estimate material requirements. [ ] The starting point for the models are estimates of the major components of GNP for some future period. These may be estimates purchased from a forecasting service or may be produced in-house. The projections are translated into industrial final demands using DITT (Demand Impact Transformation Tables), a system developed at FPA. Then using a version of the current Bureau of Economic Analysis input-output model, estimates are made of the gross output of each industry necessary to support the level and composition of GNP as specified by the macro-economic model.

Jan 1, 1977

By Frank Ittner

In this section it is proposed to discuss operating methods considered good practice under the various field conditions commonly encountered. Efficient field direction and types of equipment needed to meet transportation problems are considered only to the extent that the desire to produce the best possible records must sometimes give way to the factor of cost. As in all engineering projects, alternative possible methods of operation must be considered in the light of relative costs as well as of the quality of results obtained, Cost may be in the background of much that is done in the field operations, but only the effect on record quality will be considered here. Record quality at a particular shot point may vary with the various factors of spread character (relative positions of geophones and shot point), shot-hole depth, formations opposite position of shot, size of charge, the effect of repeat shots, surface geology and culture in the immediate vicinity of the geophones, recorder instrument characteristics, particularly filter.

Jan 1, 1940

Optimism over the continued growth of coal ex- ports received a significant shot in the arm September 18 at Norfolk, Va., when huge, new ship coal-loading facilities of the Norfolk & Western Railway were formally dedicated before a large audience of American and foreign dignitaries. Guest of Honor at the occasion was Christian A. Herter, Special Representative for Trade Negotiations, who, in a speech, stated, "The prospects for the expansion of our coal exports are excellent. The competitive pricing and high quality of our coals, whether for the production of coke for steel mills or for the generation of electric power, have won the respect of consumers everywhere in the world. Last year, the United States coal industry exported over 40 million net tons. . . . There are excellent reasons to believe that by 1970 we shall be exporting at double this rate."

Jan 10, 1963