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By Donald J. Drinkwater, M. C. Fuerstenau

Many important contributions to the more fundamental aspects of mineral processing have been made this past year. Mular1 researched the flotation characteristics of pure zinc oxide and also samples that had been doped with Al+++ and Cu++. Correlation of the response of pure zinc oxide to oleate flotation with a calculated zpc (from solution equilibrium) suggests that adsorption of oleate ion is coulombic in nature. Doping the sample with Al+++ (which will make the ZnO more n-type) had a marked effect on the maximum value of pH at which 50% recovery was obtained at constant collector addition. That is, when 0.5 mole percent Al+++ was added, the pH for 50% recovery was reduced by about four units. Treatment with Cu++ was found to have little effect on the flotation response of zinc oxide, even for additions of one mole percent. Since the zero points of charge of the Al+++ doped powders were not measured, it was not possible to correlate flotation data of these samples directly with charge phenomena.

Jan 2, 1966

By D. G. Wilder

D.G. Wilder I found the suggestion that the amount of displacement of a fault can be numerically related to the thickness of gouge or breccia to be both intuitively satisfying and intriguing. I have long agreed that there is some type of relationship between the amount of gouge and the amount of displacement of faults. I congratulate the author for developing a numerical relationship between them. However, I am concerned that the limits for applying this relationship be fully understood. An underlying assumption in this approach is that there is either a uniform thickness of gouge or breccia along a given fault or the thickness does not vary widely. Since it is not always possible to confirm this, the displacements derived by this method should be viewed with caution unless significant fault extent can be observed. At the Nevada Test Site, in drifts constructed in granite for test emplacement of spent nuclear reactor fuel, we found a fault with 0.3 to 0.4 m (12 to 16 in.) of clay gouge. Within a few meters of this location, the fault had no clay gouge, but rather consisted of a highly fractured zone with significantly altered rock and some slickensides. Based on Fig. 1, the 0.3 to 0.4 m (12 to 16 in.) thickness of gouge would indicate a displacement in excess of 30 m (98 ft). However, no gouge thickness would indicate essentially no displacement. Based on a quartz vein that terminated on the fault, and is not identified nearby, an estimated displacement of more than a few meters was made. This estimate is consistent with that obtained using the regression line proposed in the paper if the 0.3 to 0.4 m (12 to 16 in.) thickness for the gouge is used. However, using the regression curves with zero thickness would not yield results consistent with what was observed in the field. Therefore, it is important to recognize that the suggested procedure would properly yield a range of probable displacements. ? *Work performed under the auspices of the US Department of Energy by the Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. Reply by E.C. Robertson It is certainly true that the t (thickness) of gg-bx (gouge and breccia) on a fault does vary along the fault. My observations have been that near the termination of a fault, the displacement d is small and the t is also small, whereas the maximum d and t will usually be found in the central part of the fault. The information on gg-bx and t of the fault found in granite in the NTS tunnel by Mr. Wilder could be interpreted somewhat differently than he does. He speaks of the fault changing within a few meters from 0.3 to 0.4 m (12 to 16 in.) of clay gg to "a highly fractured zone with significantly altered rock and some slickensides," but no gg. The highly fractured rock may be taken to be bx, rock not so finely ground as gg but still crushed by the fault movement, equivalent to the gg in my usage, and probably occupying about the same t. Mr. Wilder's estimates for the fault in the NTS tunnel for t of 0.3 to 0.4 m (12 to 16 in.) and for d of a quartz vein, in excess of "a few meters," would place the point on the low side of the central trend line in my Fig. 1, at the lower limit. There is, of course, a problem with determining d using displacement of only one planar surface. It would be greater or lesser depending on the rake of the movement. Finally, estimating the d of a fault from its t should be made with awareness of our present uncertainties, as pointed out by Mr. Wilder. Although the central trend line in my Fig. 1 has a ratio of d/t of 100, I have put the limiting ratios at 10 and 1000. Understanding of the values of the ratio will be improved only with collection of more data, for which the discussion of Mr. Wilder is much appreciated. ? G.C. Waterman E.C. Robertson's paper provides significant information to a geologist attempting to deduce fault offset by noting the products of structural dislocation. However, considerable mapping in underground and open-pit mines, and examination of structures produced in different geological settings, have convinced me that gouge and breccia thickness are controlled by geological conditions and fault movement. The following paragraphs suggest geological variables that control them. 1. Depth of Loading A near-surface fault resulting from tensional stress has more breccia/gouge than is produced by a similar stress at considerable depth. A deep-loaded compressional stress may produce a linear zone of schist, or structural dislocation may occur along an earlier formed belt of schist. Such "shear zones" are common in Canadian mines in precambrian rocks. In neither case can offset be directly deduced by an analysis of the minimal gouge/breccia in the shistose rocks. At greater depth, stress may be partially to wholly relieved by flowage. I vividly recall first noting the regional "Midas Thrust" in the Lark mine, Bingham Mining District, UT (where we called the structure the North Fault). My recorded notes, as I remember them, showed a narrow gouge streak separated the "Jordan" and "Commercial" limestone units from impure, muddy limestone beds of uncertain stratigraphic position. The visible structure did not indicate the great importance of this premineral fault

Jan 1, 1985

By Charles L. Elliot

Worldwide manpower utilization reached a new high at 10,482 professional man-months and expenditures increased to $19.9 million for mining geophysical activity during 1965. This is up from 9323 man-months and $14.5 million in 1964. Worldwide geophysical activity measured in percent distribution of the total manpower utilization and expenditures is presented in the accompanying Figs. 1 and 2. In terms of the total manpower utilization, ground surveys accounted for 61%, airborne surveys 18%, and mining geophysical research activity 21%. For expenditures, the breakdown was ground surveys, 49%; airborne surveys, 3901o; and research, 12%. Industry was responsible in general for 74% of the manpower utilization and 80% of the expenditures. Manpower costs in 1965 averaged $1900 per professional man-month.

Jan 11, 1966

By S. Isserow

RECENTLY, a description of the wartime work in this laboratory on the U-Si phase diagram was published. This diagram was available earlier in the open literature; as were Zachariasen's crystal structure identifications for the compounds in the system. The uranium end of the phase diagram is shown in Fig. 1. The most recent work on this system has emphasized the peritectoid E phase, of particular interest for a number of reasons. The early work provided evidence of this phase's resistance to corrosion in water and of its slight ductility. Further information on these properties has been obtained here. Work elsewhere4 has provided evidence of stability under irradiation. This body-centered-tetragonal phase is relatively isotropic compared to the more usually applied a or ? uranium phases. Unlike the other compounds in this system, it contains no Si-Si covalent bonds.3 In addition, consideration on the basis of Pauling's concepts leads to the conclusion that in the E phase, uranium has a higher valence than in any of the other phases. Definition of the composition of the ? phase has been of prime concern in the study of this alloy. Evidence is presented below that its silicon content is slightly higher than that of stoichiometric U8Si, the composition frequently assigned this phase on the basis of Zachariasen's identification. This work on the composition required careful attention to the method of dissolving the alloy for analysis, since apparently low silicon contents could be found under certain conditions, see Appendix. Preparation: Melting, Casting, and Heat Treatment—Almost all the samples were from castings with a diameter of 13/4 or 2 in. and about 1 ft long, weighing 10 to 15 lb. The U-Si charge was melted by heating to about 1650°C in an induction heated vacuum furnace. Beryllia crucibles were used at first, but were replaced by zirconia-washed graphite as the technique of keeping the carbon content low enough (about 500 ppm) was mastered. The alloy was bottom-poured at about 1650°C into graphite molds. A few small buttons, weighing no more than 50 g, were prepared in a small arc melting unit.' Since cast material has a preponderance of uranium and U8Si2, heat treatment is necessary to ob-tain the ? phase by the solid-solid peritectoid reaetion. Once obtained, the ? phase is stable to room temperature, obviating the need for speeial attention to the method of cooling after epsilonization, see Fig. 1. It was found desirable to epsilonize at 800°C for a week. For some purposes, in which residual uranium and/or U8Si2 are tolerable, shorter periods may be adequate. The temperature of 800°C is not critical, since essentially the same results were obtained from 785° to 825°C. Further departure from this epsilonization range is inadvisable.

Jan 1, 1958

By William A. Johnson

The mathematical analysis of diffusion curves in solid metals is carried out ordinarily by analogy with the flow of heat in a continuous medium and no account is taken of the fact that the materials involved are composed of discrete particles that move discrete distances at irregular intervals. It is possible to treat the problem on the basis of simple assumed atomic mechanisms, in which case, because of the small scale of the elementary process compared to the gross effects observed experimentally, the two procedures lead to the same expression for the variation of concentration with distance. Thus, for engineering purposes, the usual methods are quite satisfactory. If, on the other hand, our purpose is to go beyond the mere collection of data, however desirable this may be, it is necessary to recognize and understand the factors that are of fundamental importance. One factor that has not hitherto been considered when dealing with solid metals is the difference in atomic weights of the isotopes of a single metal. While all the atoms of a given element are alike chemically, their weights may vary by a small but significant amount, and atoms of different weights may have different diffusion rates. With gases this variation in isotopic weight produces a change in the rate of diffusion by a factor inversely proportional to the square root of mass. While, except for the lightest gases, this is not a large effect, it is, for example, sufficient to permit a considerable concentration of one isotope at the expense of others. If metals exhibit a similar phenomenon, some modification of the analysis of the diffusion process will be required, since the different isotopes of a given metal will have different probabilities of moving and the heat-flow analogy will contain a fundamental error. This situation cannot be rectified by using a diffusion coefficient based on the average probability of moving, and it can be shown that even when the diffusion coefficient is independent of composition, the diffusion curve will not agree with the simple theory except in the rare cases where only one isotope exists; e.g., gold. If, however, the mass effect in the solid state were no larger than in the gaseous, the errors arising therefrom in the analysis of ordinary diffusion curves would be quite negligible. Nevertheless, our desire to obtain all possible information concerning the details of the diffusion process, and the possibility of diffusion in the solid state as a means for separating isotopes are cogent reasons for undertaking an experimental study to determine whether isotopes of different masses diffuse at different rates. Experimental Procedure If isotopes of different masses diffuse at different rates, the ratio of the concentration of one relative to another will vary with the distance from the diffusion inter-

Jan 1, 1946

By William A. Johnson

The mathematical analysis of diffusion curves in solid metals is carried out ordinarily by analogy with the flow of heat in a continuous medium and no account is taken of the fact that the materials involved are composed of discrete particles that move discrete distances at irregular intervals. It is possible to treat the problem on the basis of simple assumed atomic mechanisms, in which case, because of the small scale of the elementary process compared to the gross effects observed experimentally, the two procedures lead to the same expression for the variation of concentration with distance. Thus, for engineering purposes, the usual methods are quite satisfactory. If, on the other hand, our purpose is to go beyond the mere collection of data, however desirable this may be, it is necessary to recognize and understand the factors that are of fundamental importance. One factor that has not hitherto been considered when dealing with solid metals is the difference in atomic weights of the isotopes of a single metal. While all the atoms of a given element are alike chemically, their weights may vary by a small but significant amount, and atoms of different weights may have different diffusion rates. With gases this variation in isotopic weight produces a change in the rate of diffusion by a factor inversely proportional to the square root of mass. While, except for the lightest gases, this is not a large effect, it is, for example, sufficient to permit a considerable concentration of one isotope at the expense of others. If metals exhibit a similar phenomenon, some modification of the analysis of the diffusion process will be required, since the different isotopes of a given metal will have different probabilities of moving and the heat-flow analogy will contain a fundamental error. This situation cannot be rectified by using a diffusion coefficient based on the average probability of moving, and it can be shown that even when the diffusion coefficient is independent of composition, the diffusion curve will not agree with the simple theory except in the rare cases where only one isotope exists; e.g., gold. If, however, the mass effect in the solid state were no larger than in the gaseous, the errors arising therefrom in the analysis of ordinary diffusion curves would be quite negligible. Nevertheless, our desire to obtain all possible information concerning the details of the diffusion process, and the possibility of diffusion in the solid state as a means for separating isotopes are cogent reasons for undertaking an experimental study to determine whether isotopes of different masses diffuse at different rates. Experimental Procedure If isotopes of different masses diffuse at different rates, the ratio of the concentration of one relative to another will vary with the distance from the diffusion inter-

Jan 1, 1946

By William A. Johnson

THE mathematical analysis of diffusion curves in solid metals is Carried out ordinarily by analogy with the flow of heat in a continuous medium and no account is taken of the fact that the materials involved are composed of discrete particles that move discrete distances at irregular intervals. It is possible to treat the problem on the basis of simple assumed atomic mechanisms, in which case, because of the small scale of the elementary process compared to the gross effects observed experimentally, the two procedures lead to the same expression for the variation of concentration with distance. Thus, for engineering purposes, the usual methods are quite satisfactory. If, on the other hand, our purpose is to go beyond the mere collection of data, however desirable this may be, it is necessary to recognize and understand the factors that are of fundamental importance. One factor that has not hitherto been considered when dealing with solid metals is the difference in atomic weights of the isotopes of a single metal. While all the atoms of a given element are alike chemically, their weights may vary by a small but significant amount, and atoms of different weights may have different diffusion rates. With gases this variation in isotopic weight produces a change in the rate of diffusion by a factor inversely proportional to the square root of mass. While, except for the lightest gases, this is not a large effect, it is, for example, sufficient to permit a considerable concentration of one isotope at the expense of others. If metals exhibit a similar phenomenon, some modification of the analysis of the diffusion process will be required, since the different isotopes of a given metal will have different probabilities of moving and the heat-flow analogy will contain a fundamental error. This situation cannot be rectified by using a diffusion coefficient based on the average probability of moving, and it can be shown that even when the diffusion coefficient is independent of composition, the diffusion curve will not agree with the simple theory except in the rare cases where only one isotope exists; e.g., gold. If, however, the mass effect in the solid state were no larger than in the gaseous, the errors arising therefrom in the analysis of ordinary diffusion curves would be quite negligible. Nevertheless, our desire to obtain all possible information concerning the details of the diffusion process, and the possibility of diffusion in the solid state as a means for separating isotopes are cogent reasons for undertaking an experimental study to determine whether isotopes of different masses diffuse at different rates. EXPERIMENTAL PROCEDURE If isotopes of different masses diffuse at different rates, the ratio of the concentration of one relative to another will vary with the distance from the diffusion inter-

Jan 1, 1946

By Edward C. J. Urban

THE nature of certain pernicious dusts commonly encountered in the removal of iron ore from the underground mines of the Lake Superior district is recognized, and appropriate measures for the protection of individuals subjected to these dusts have been applied in most mines for more than to years. Undoubtedly the principal concern has been demanded by dusts that contain as a constituent silicon dioxide in its free or uncombined state, the mineral we all know as quartz or chert. Investigators1 agree that among the factors that determine injurious exposure are: the composition of the dust, the concentration suspended at the breathing level and the duration of the exposure. We have on hand data that describe the experience of several underground iron-ore mines in the Upper Peninsula of Michigan and Wisconsin in regard to these factors, which in a large measure also reflect the general experience of the other mines of the area. We believe that a discussion of these data will indicate the effectiveness of the dust-control methods that have been considered good practice and that have been employed over a long period of time. A silicosis-prevention program was ini¬tiated by the iron mines of the Upper Peninsula in 1934 and records of mine dustiness are available from that date to the present time. For dust conditions previous to 1934 the results of observations conducted in other industries can be utilized together with local information pertaining to the development and initial application of rock-drilling equipment. DEVELOPMENT OF ROCK DRILLS The earliest percussion rock drill that later had any industrial use was patented in this country in 1851.2 This machine was later modified and improved in many respects but its piston-type design remained standard for drilling equipment in most mines for the next 63 years.3 The piston drill was operated either by air or by steam. It employed a solid drill steel, fastened directly to the reciprocating piston. The drilling was done dry except in holes directed at an angle below the horizontal. For these water was manually injected into the hole and the pumping action of the rod expelled the sludge. The dry cuttings from drillings inclined above the horizontal fell from the hole by their own weight. A development of major importance from the standpoint of dust generation and control occurred with the invention by J. G. Leyner of a hammer-type rock drill that embodied the essential feature of a drill steel with a hollow core. His patent was secured in 1897. The machine was a radical departure in drilling method. The steel was held loosely in a chuck while

Jan 1, 1947

By M. T. Simnad, G. Derge, Ling Yang

STUDY of diffusion in molten substances is important in at least two respects. Diffusion data, combined with thermodynamic and kinetic information, throw light on the structure of the liquid state. Moreover, a knowledge of diffusion coefficients and their temperature dependence is useful in ascertaining the controlling step in many metallurgical reactions. Although diffusion measurements have been made on a number of molten salts, slags, metals, and alloys,'-'" the results available are still limited and widely scattered, especially for the high temperature melts. It is the purpose of this investigation to establish reliable procedures for the measurement of self-diffusion coefficients in high temperature melts and to use these procedures to determine the self-diffusion coefficients of iron in molten Fe-C alloys of different carbon contents. Experimental Measurement of self-diffusion coefficients in high temperature melts is usually carried out by using one of two methods. In the first, diffusion takes place between two cylindrical samples of the same material, one of which is made radioactive. The diffusion coefficient is calculated from the radioactivity penetration curve in the solidified sample after the diffusion. In the second method, samples contained in capillaries of an inert substance are immersed in an infinite reservoir of the same material. Either the material in the capillary or that in the reservoir is made radioactive and the diffusion coefficient is calculated from the change of the radioactivity of the sample in the capillary after the diffusion. The second method is simpler because a radioactivity penetration curve is not needed for the calculation of the diffusion coefficient; however,.it is valid only when no convection has occurred in the capillary during the diffusion. A radioactivity penetration curve is therefore always useful in indicating that the required conditions for the diffusion are ful- filled. Towers and Chipman" recently studied the self-diffusion of calcium and silicon in CaO-Al,O,-SiO, melts by using the capillary method. Instead of measuring the change of the radioactivity of the sample in the capillary, they autoradiographed the sample after the diffusion and calculated the diffusion coefficient from the intensity distribution of the autoradiograph. Their method is useful when the radioactive isotopes are weak ß-emitters, but is very difficult, if not impossible, to apply to cases involving strong ß or y-emitters. For such cases, sectioning of the sample according to the method of Morgan and Kitchener' may be used for the construction of the radioactivity penetration curve. The self-diffusion of iron in molten Fe-C alloys has been studied in this manner and the experimental procedures are described as follows: The diffusion apparatus is shown schematically in Fig. 1. The bath consisted of about 200 g of an Fe-C

Jan 1, 1957

By Arthur T. Ward

DESPITE the intense preoccupation of most of those members connected with the mining, concentration, and reduction of iron ores, the luncheon and subsequent technical session of the Eastern Magnetite Committee were exceedingly well attended. Many of the older faces were absent, but new ones took their places. More than sixty, all told, took in the technical session. Chairman Crockett opened the session by calling upon Meredith E. Johnson, whose paper, with its accompanying graph, was in reality a comprehensive historical review of iron mining from colonial days to the end of 1941. with some notes on current expansion which indicates that New Jersey is destined to become a still more important. factor in the production of magnetite ores.

Jan 1, 1942

By D. J. Brown

Froth flotation is now used to recover millions of tons of fine coal,(-1/2 mm), every year. For example, in Great Britain, 4-million tons of flotation concentrate was produced in 1960, about 3% of the mechanically cleaned out- put and 2% of the total salable output. Coal flotation is not so widely practiced in the U. S. as it is in Europe since much American coal occurs in thick seams of high grade and does not require cleaning. However, in the U. S., as elsewhere, the increasing mechanization of coal mining machinery has lead to a lowering in size and grade of product from the mine and to an increasing need for cleaning of coal to improve the grade before sale. With an increasing proportion of fines in the product, froth flotation has assumed a greater importance as a cleaning process for coal. In the last three years, over 40 flotation plants have been put into operation in the Appalachian area of the U. S.80 Fine coal recovered by means of froth flotation may be used as a powdered fuel alone or mixed with coarser grades. The removal of this fine coal from washery water makes possible the recirculation and re-use of the water and also leads to improved and more consistent operation of jigs and other separating machines which function less effectively when there is a build-up of fine solids in the washery water. Finally, froth flotation is of assistance in the production of a clarified effluent which may be discharged from the washery without polluting local rivers, streams, or wells. The 1961 cost of installing a new coal flotation plant in Great Britain would be about $19,000 per ton of dry solids input per hour, including the cost of new buildings and coal and shale filtration and water clarification equipment. The figure for the gravity concentration of the large coal, the main plant, would be about $4,800 per tph. The operating cost for the new coal flotation plant would be about $1.10 per ton. Even at this level of cost the cleaning operation is economic in Great Britain for coking coals. In the U. S., a froth flotation cost of 14$per ton of cleanfilter cake was quoted early in 1958 for one operation,l though admittedly this was a special case. Assuming a cake moisture con- tent of 30%, it is estimated that this cost is equivalent to a figure of 256 per ton of dry solids input, for the incorporation of coal flotation in an existing washery. A cost oh 416 per ton of concentrate was quoted76 in a recent analysis of flotation economics, this cost being brought up to $1.11 per ton after payment of royalty, welfare and association dues and taxes. Capital cost was $120,000 for a plant producing 133 tpd of concentrate. Before considering the treatment of coal by flotation it is appropriate to survey some of the properties of coal which are of importance in the process.

Jan 1, 1962

By H. Scott

Since Bohler discovered, in 1903, on cooling certain alloy steels, the phenomenon of a new and lower temperature transformation than the usual Ar 3-2-1 obtained by increasing the maximum temperature to which the material was heated, much has been published1 connecting this phenomenon with a large number of dissimilar steels of high alloy content. From the fact that the transformation divides itself, taking place at two widely separated temperatures, it has been called a "split transformation." The significant facts established by recent investigators2 are: that when the transformation occurs at the higher temperature Ar1, troostite or a decomposition product is formed, and that when the transformation occurs at the lower temperature Ar", the resulting structure is martensite. The terminology Ar' and Ar" adopted here is that of Portevin. Previous Investigations Reviewing the work on this subject published in a recent issue of Revue de Metallurgie and referring in particular to his statement that martensite is a solution of carbide in alpha iron, Le Chatelier says :4 "How then can a theory already 20 years old demand new investigations? The reason for it is that we have not succeeded in proving directly the real presence of the transformation of iron during the very short duration of the quenching. The fall of temperature takes place at the rate of several hundred degrees per second and the observation of

Jan 1, 1920

By Edward C. J. Urban

The nature of certain pernicious dusts commonly encountered in the removal of iron ore from the underground mines of the Lake Superior district is recognized, and appropriate measures for the protection of individuals subjected to these dusts have been applied in most mines for more than 10 years. Undoubtedly the principal concern has been demanded by dusts that contain as a constituent silicon dioxide in its free or uncombined state, the mineral we all know as quartz or chert. Investigators1 agree that among the factors that determine injurious exposure are: the composition of the dust, the concentration suspended at the breathing level and the duration of the exposure. We have on hand data that describe the experience of several underground iron-ore mines in the Upper Peninsula of Michigan and Wisconsin in regard to these factors, which in a large measure also reflect the general experience of the other mines of the area. We believe that a discussion of these data will indicate the effectiveness of the dust-control methods that have been considered good practice and that have been employed over a long period of time. A silicosis-prevention program was ini- tiated by the iron mines of the Upper Peninsula in 1934 and records of mine dustiness are available from that date to the present time. For dust conditions previous to 1934 the results of observations conducted in other industries can be utilized together with local information pertaining to the development and initial application of rock-drilling equipment. Development of Rock DriI,I.s Thc earliest percussion rock drill that later had any industrial use was patented in this country in 1851.2 This machine was later modified and improved in many respects but its Piston-Type design remained standard for drilling equipment in most mines for the next 63 years.3 The piston drill was operated either by air or by steam. It employed a solid drill steel, fastened directly to the reciprocating piston. The drilling was done dry except in holes directed at an angle below the horizontal. For these water was manually injected into the hole and the pumping action of the rod expelled the sludge. The dry cuttings from drillings inclined above the horizontal fell from the hole by their own weight. A development of major importance from the standpoint of dust generation and control occurred with the invention by J. G. Leyner of a hammer-type rock drill that embodied the essential feature of a drill steel with a hollow core. His patent was secured in 1897. The machine was a radical departure in drilling method. The steel was held loosely in a chuck while

Jan 1, 1949

By David Swan

No mystery shrouds the discovery of chromium. The indefatigable French chemist Vauquelin, in reporting his discovery of this chemical element to 1'Institut National in 1798, concluded his discourse with the statement: "I place before the eyes of the Institute a small quantity of chromium and several of its most re- markable combinations." Working with the so-called "red lead of Siberia, Vauquelin not only prepared numerous chemical compounds of the new metal, but he reduced the oxide to the metallic state. These chemical compounds possessed a variety of remarkably distinctive colors; so, acceding to suggestion, Vauquelin named the new element chrome (chromium), a derivative of the Greek word chroma, meaning color. Siberian "red lead" (crocoite) was not plentiful; however, it was not long before Vauquelin's prediction was realized that the chemical compounds of chromium would become useful in the arts when sources of chromium became more readily available. Although chrome-iron ore (chromite) became obtainable in France, the United States and elsewhere during the early part of the nineteenth century, it is interesting to note that from 1828 to about 1860, Maryland, Pennsylvania, and others of the eastern United States furnished almost the entire chrome-ore requirements of the world. Several countries each in turn have since dominated for certain periods the supply of chromite. In recent years, the largest tonnages have come

Jan 1, 1953

An Interstate Mining Commission organized in Raleigh, N. C., on April 27 still has no offices, no budget and only four members, but it could spell the beginning of the end for the state-to-state environmental control variations that have lately been con- founding the mining industry. Established by Kentucky, North Carolina, Oklahoma and Pennsylvania, the new organization is committed to protecting land, water and other resources through improved strip and other mining practices. In pursuit of this end, it has broad authority to study all mining activities affecting the environment and to recommend improvements in mining practices and in laws regulating the mining industry. The Startup The Commission was created under an interstate Mining Compact enacted in the 1960's by the legislatures of the four member states. According to the rules of this Compact, the Commissioners in the new organization are, ex officio, the governors of the member states-namely, Chairman Louie B. Nunn (Ky.), Vice Chairman Robert W. Scott (N.C.), David Hall (Okla.) and Milton J. Shapp (Pa.). Each Commissioner, however, must appoint an advisory body to counsel him in matters relating to Commission business and delegate one member of this body to act as his alternate. Each advisory body must include representatives of mining, conservation and other public and private interests.

Jan 1, 1971

A school grows big only as its usefulness increases and it will shrink rapidly if inefficient. Usefulness must be recorded in terms of service within the economic structure of the Commonwealth. Under this premise, modern mineral industries colleges must recognize and give equal significance to three interrelated, interdependent functions of service: namely, (1) resident instruction, on both the undergraduate and graduate levels; (2) research under an experiment station plan; and (3) extension training under three classifications, class instruction, correspondence instruction, and informal instruction. To train potential leaders for the mineral kingdom, to discover and teach new truths is only half of the job. Through extension training, equal attention must be given to the on-job, vocational-technical, upgrading of skilled workers on the production line. Similar to the School of Agriculture, the School of Mineral Industries is the only one in the Commonwealth offering the three functions of service in each of the subject-matter fields in mineral arts and sciences. The functions of service must be based on the modern conception of mineral conservation (Fig. 12). Conservation of minerals differs from conservation of natural resources in general because man must find new mineral deposits and excel the geologic forces of nature in processes of concentration. True mineral conservation, therefore, may be defined as energetic discovery,

Jan 1, 1950

By Adrian E. Ross

Diamond drilling through caving formations at depths greater than ZOO0 ft has long presented serious difficulty, generally solved either by casing or cementing. Casing is permitted only when the resulting smaller hole is acceptable, and cementing is frequently a problem at depth. A new method that injects cement under pressure at the desired location is an aid in diamond drilling deep holes. DRILLING through caving formations in diamond drill holes at depths greater than 2000 ft has long been a serious problem. These caving formations are normally passed only by casing the hole or by cementing the hole. Casing the hole is possible only when a resulting smaller hole is acceptable. In as much as only a limited number of reductions are economically practical, cementing is frequently considered the only method suitable for solving these problems. Cementing either by pumping a slurry into the hole or by dropping cylinders containing cement has proved satisfactory on holes under 2000 ft. In holes substantially deeper than 2000 ft these methods are not satisfactory, since during the pump- ing process cement separates out, whereas cylinders usually break before the bottom of the hole is reached. A new procedure, the injector method, apparently solves these problems.* With this method, cement is lowered in the hole in a cylinder, the cement being

Jan 1, 1953

By Adrian E. Ross

Diamond drilling through caving formations at depths greater than ZOO0 ft has long presented serious difficulty, generally solved either by casing or cementing. Casing is permitted only when the resulting smaller hole is acceptable, and cementing is frequently a problem at depth. A new method that injects cement under pressure at the desired location is an aid in diamond drilling deep holes. DRILLING through caving formations in diamond drill holes at depths greater than 2000 ft has long been a serious problem. These caving formations are normally passed only by casing the hole or by cementing the hole. Casing the hole is possible only when a resulting smaller hole is acceptable. In as much as only a limited number of reductions are economically practical, cementing is frequently considered the only method suitable for solving these problems. Cementing either by pumping a slurry into the hole or by dropping cylinders containing cement has proved satisfactory on holes under 2000 ft. In holes substantially deeper than 2000 ft these methods are not satisfactory, since during the pump- ing process cement separates out, whereas cylinders usually break before the bottom of the hole is reached. A new procedure, the injector method, apparently solves these problems.* With this method, cement is lowered in the hole in a cylinder, the cement being

Jan 1, 1953

By W. C. Coffin

The refractory linings of open-hearth steel furnaces above the bath line are subject to severe wear not only from the heat caused by the combustion of the fuel and the reactions of the bath, but also from the melting action of the gases when not controlled and directed, and from the scouring of the oxides, etc. with which the products of combustion are charged. The framework that encases or binds the furnace is made up primarily of an iron or steel pan in which the furnace proper is built, side and end buckstays, and tie-rods. The expansion and contraction are so great and variable that the bindings may be subjected to severe stresses unless the tie-rods are carefully adjusted in heating up the furnace, but they are most affected by direct heat and usually become deformed from that cause when the lining is worn thin and, sometimes, when sections of the lining fall in and expose some of the framework. A deformed framework displaces the skewback of the roof arch and tends to distort or crush the roof. Bent buckstays deform the front wall, causing the door frames to stand away from the lining so that the gases burn between the lining and the frames, destroying both of them. Frequently the frames are attached to the buckstays; then when the latter bend the frames usually break. Preventing the distortion of the framework and maintaining the economy of the refractories are real factors in the cost of steel making. Nat only does the cost of general repairs and reconstruction add directly to the cost of steel produced, but the time lost in making repairs cuts down the steel production and increases the overhead expense of both the furnace shop and its allied foundry or mills. Many years ago water-cooled equipment applied to iron blast furnaces made it possible to increase greatly not only the size and production of the furnaces but also the life of the lining. It also cut down the loss from frequent repairs. The open-hearth furnace is a much later invention, especially as a commercial factor; for though it dates from the Fred Siemens patent of 1856, much more progress was made in the Bessemer process until the latter eighties and most of the development

Jan 1, 1920

By Frederick T. Fischer

The New Jersey Zinc Company began a program of exploration in Middle Tennessee in 1964. The target horizon of the exploration project has been the Knox Dolomite which is a low-yield aquifer over nearly the entire Central Basin of Tennessee (1). With the exception of a few hundred acres in the Wells Creek and Flynn Creek disturbances (astroblemes?), the Knox Dolomite in Middle Tennessee is known only in subsurface. In January of 1969, New Jersey Zinc announced the discovery of a major zinc deposit near Elmwood, southeast of Carthage. This is on the northeastern flank of the Nashville Dome where the nearly flat-lying beds have an average eastward slope of about 50 feet per mile. The anticipated development of a mining situation has emphasized the significance of hydrologic relationships in the region as a whole and especially in the Elmwood area. These relationships affect several areas of concern which ma be generally grouped into two broad classes; i. e. , (1) Problems of a Public Nature - involving the prevention of the contamination of potable aquifers, the prevention of the contamination of surface waters, the prevention of the capture of presently utilized water, etc.; and (2) Problems of Mining Economics - involving pumping capacity and costs, the possible need for equipment of special composition, underground environmental conditions, etc. Exploration drilling in Middle Tennessee has contributed additional information about the Knox aquifer and

Jan 1, 1970