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By P. R. Gage, R. W. Bartlett

SILICIDE coatings on refractory metals are often applied by transporting a silicon halide vapor to a hot metal surface where dissociation or hydrogen reduction occurs. The subsequent chemical reaction to produce the coating requires diffusion of silicon or the refractory metal through the in situ silicide layer. This solid-state diffusion process step is often slower than the vapor-transport step and, therefore, rate controlling. This situation is analogous to the parabolic oxidation of metals in which the oxidation rate is controlled by diffusion through the oxide layer. The purposes of this study were to 1) measure the rate of formation of MoSiz and MoSi2 coatings under conditions such that the silicide diffusion process is rate controlling and lower silicide compounds are not formed and 2) determine by a marker experiment whether silicon or the respective refractory metals are the principal diffusing species in the disilicides.

Jan 1, 1965

Papers in Classes A-Metal Mining, B-Milling and Concentration, H-Industrial Minerals, and I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Papers in Classes C-Iron and Steel Division, D Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. Papers in Class G Petroleum Division are distributed in PETROLEUM TECHNOLOGY, which is issued every other month. TECHNICAL PUBLICATIONS in Classes F-Coal Division, J Mineral Industry Education Division, Mining Administration, and L-Geophysics, are issued as separate pamphlets. Contributions are papers that when printed or mimeographed are available, but only on request.

Jan 1, 1946

By Donald F. Kennedy

During the past several years Climax Molybdenum Co. has been engaged in testing various types and sizes of hollow drill steel. The majority of tests have been on 7/8-in. hexagon st.ee1, inasmuch as it represents approximately 70% of total drill steel consumption at the Climax operation. Prior to December 1960, tests on 7/8-in. hexagon drill steel were conducted on steel with a forged collar and, in most cases, with a threaded bit connection. Through these tests and research, some improvement in steel life was achieved by making changes in heat treatment, design and alloying constituents. However, during that month, research and testing commenced on a rubber collar which was designed to replace the forged collar on 7/8-in. hexagon drill steel. Manufactured by the LeRoi Div. of Westinghouse Air Brake Co.. the collar. is very simple in design, consisting of a 1 ½ -in. diam steel cylindrical sleeve 2 in. long, containing a bonded rubber insert and attached to the steel with an epoxy cement

Jan 8, 1962

By August E. Vandale

Mining of the Freeport and Pittsburgh coal seams in the Pittsburgh vicinity dates back more than 100 years, and Consolidation Coal Co., or its predecessor, Pittsburgh Coal Co., has been actively mining in the area since 1900. Over the years, Consol has acquired good legal title to the coal lands purchased from individual farm owners, with broad mining rights, and in 98% or more of its title holdings, the company has a complete waiver of surface damage or the right to subside the surface land. (Titles in Pennsylvania can be in three forms: title in fee; title to the mineral; or mining rights permitting the removal and extraction of the mineral with or without waiver of surface damage.) In the early history of Consol, individual farms overlying the seams were purchased from land owners. Many of these titles severed the coal estate from the "in fee" title, and mining rights with waiver of surface damage were conveyed in the original severance deed. In this manner, Consol was able to put together its large mineable coal reserves. Consol has practiced "full recovery" mining as far as practical from its early years of hand loading to the recent era of mechanization.

Jan 9, 1967

By G. Hergert

SUMMARY Three gradients have been identified in regard to the average horizontal ground stress increase with depth. [S (0-900 m) = 9.86 MPa + 0.0371 MPa/m SHa (900-2200 m) = 33.41 MPa + 0.0111 MPa/m SHae (extreme)= 12.36 MPa + 0.0586 MPa/m] The extreme stress values are not caused by mining geometry and are of limited extent only. In some cases geological disturbances like faults and rock type boundaries suggest an explanation but in other cases the unusually high stresses cannot be explained readily. It is interesting to note that in the same locations the vertical stress components are very much higher than those derived from overburden weight and that the vertical stress gradient is similar to the gradient obtained from the extreme horizontal stress components. INTRODUCTION Ground stress determinations have been carried out in mines in Ontario and Manitoba, Canada, over more than a decade (Herget, 1980). Most of the sites are located in the Superior and Southern Tectonic Province of the Canadian Shield, which consist of Archaen and Proterozoic rocks comprising volcanics, metamorphosed sediments and granites. The youngest orogenic deformation occurred during the Grenville Orogeny (955 million years ago).

Jan 1, 1982

By E. W. Codington

The pebble-phosphates of Florida occur in a district roughly bounded on the north by the 28th parallel, on the east by an irregular line running a few miles east of Peace river and on the west by the Gulf of Mexico, and covering an area of about 4000 square miles. There seems to be no reason why the deposits should not extend farther south along the gulf coast. That section remains unprospected, transportation-facilities being non-existent. It is not intended in this paper to discuss the geology of these formations; but a word as to their probable origin will be perhaps the best method of giving a correct idea of their present position. Starting with a low, flat surface, with even less of superficial undulation than appears at present, an im-

Jan 1, 1896

By Walter Riethmeier, Arthur J. Lynch

The future of plant design in mineral processing and extractive metallurgy is discussed in relation to present trends and the future need to build plants that will treat larger tonnages and lower grades of ore. The future equipment and plant design of crushing, grinding, screening, classification, flotation, magnetic concentration, gravity concentration, hydrometallurgy, thickening, filtration, tailings disposal, health, safety, environment, and materials of construction are discussed. Future plants are expected to follow upon present evolutionary trends. The impact of escalation, energy costs, and increased regulation of the industry is foreseen as a major influence on plant design.

Jan 1, 1978

By C. L. Dake

RESIDUAL deposits occur both as products of weathering and as products of hydrothermal decay. PRODUCTS OF WEATHERING That climatic conditions affect greatly both the rate and the results of weathering, is shown. in temperate, polar, arid, and tropical regions, each of which will be considered separately. Weathering under Temperate Climates The decomposition of any rock is accomplished by the removal of the more soluble bases, and a concentration of the relatively insoluble oxides of iron, aluminum, and silicon. By reason of its some-what greater solubility, silica is much more subject to removal than iron and alumina. The two important residual end products of weathering are sands and clays, the former consisting essentially of quartz, and the latter of kaolin and limonite.1

Jan 5, 1915

By A. E. Weissenborn

Current knowledge of the substantial resources of zinc that exist in northwestern Washington is reviewed. These zinc-lead deposits are all associated with the Kootenay Arc, a narrow arcuate belt of folded and faulted rocks that dominates the regional structure of Stevens and Pend Oreille Counties and adjacent parts of British Columbia. The deposits of the Arc are only part of a major lead-zinc silver metallogenic province that includes the deposits of the Coeur d'Alene district and the famed Sullivan ore body of Kimberly, British Columbia. Most, but by no means all the zinc-lead deposits of the Kootenay Arc are in carbonate rocks. They occur in several stratigraphic units, and in different parts of the Arc are quite diverse in character. The deposits appear to have undergone a complex geologic history and have not necessarily all been formed at the same time or by the same geologic processes.

Jan 1, 1976

Succession of Minerals and Temperatures of Formation in Ore Deposits of Magmatic Affiliations BY WALDEMAR LINDGREN (Tech Pub 713 10,000 words ) The paper presents data accepted by many geochemists and geologists regarding the succession of minerals and the temperatures of formation in ore deposits affiliated with igneous rocks It also presents the individual views of the author on the composition of the solutions that were active and on the mode of deposition He does not regard these views as speculations or hypotheses but as forming a well motivated and con¬sistent theory It is not certain, however, that all investigators will subscribe to them The mining engineer may not always be interested in the field of stability and tempera¬ture of origin in the mineralogy of ore deposits, but he certainly is interested in the succession of minerals because this has a definite bearing on the understanding of the ores and on the best processes of extraction The author, therefore, summarizes in plain language the principal features of succession as shown in metallic ores

Jan 1, 1937

By John F. Abel

In the debate between miners and ecologists, our industry has at last begun to get some of its story told. I have been told many times that it is hopeless to even try to get our side across. Some are sure that no one will believe us even when our cause is just. My reply would be that we have to tell the truth; again, again, and again. We will never convert a fanatic, but we must try to reach the reasonable and thinking people. I am encouraged because more of us are trying. Various mining companies here in Arizona have bought newspaper space to set forth some of the facts around our local environmental problems. The Arizona Mining Association co-sponsored a symposium in March: Mining and Ecology in the Arid Environment. The symposium program included tours arranged with local mining companies. The participants saw an acid plant, an acid leaching operation, an alluvial tailings dike, a tailings pond, a smelter, and a couple of open pit mines. This wouldn't phase you until you realized that half the visitors were ecologists, watershed and wild- life managers, and other assorted conservationists. It took a lot of guts. I am proud that we had that much confidence. As Pogo said, "We have met the enemy and they is us!" Actually, we met the enemy and they were just like us-concerned.

Jan 1, 1970

By T. E. Schwarz

The Red Mountain district, in Ouray County, Colorado, has been already referred to in the Transactions of the Institute, and notably in papers by Mr. T. B. Comstock, on " The Geology and VeinStructure of Southwestern Colorado" (Trans., xv., 218), and on " Hot-Spring Formations in Red Mountain District, Colorado—A Reply to the Criticisms of Mr. Emmons" (Trans., xvii., 261), and in the paper of Mr. S. F. Emmons, on " Structural Relations of Ore-Deposits" (Tram., xvi., 804). The district has attracted much attention from those interested in geology, because it seems to present a variety of ore-deposits rarely, if ever, met with elsewhere, and one which cannot be described by such well-understood terms as fissure-veins, bedded-deposits, or contact-formation. It will be the scope of this paper to note briefly, from the writer's experience in developing the Yankee Girl, Guston and other Red Mountain properties,—first, observed facts as to the ore occurrence and formation, and second, certain unsolved geological questions. The Red Mountain district proper occupies the headwaters of Red creek, from Iron ton to the Divide, a distance of 5 miles. Its leading properties occur on the west slope of Red Mountain. The mode

Jan 1, 1890

By R. M. Porter

The Sullivan mine of Consolidated Mining and Smelting Co. of Canada Ltd. is located one mile west of Kimberley. With its daily production of 10,000 tons, the mine is the largest in British Columbia and one of the outstanding mines of the world. The Sullivan orebody dips from nearly horizontal to 45". The ore zone is a bedded replacement de- posit in argillite with a width varying from a few inches up to 300 ft. The main sulfide minerals are pyrrhotite, pyrite, galena, and sphalerite. The chief metals produced are lead and zinc, with less important qualities of iron, silver, tin, antimony, bismuth, cadmium, indium and sulfur.

Jan 12, 1963

By Peter Joralemon

Peter Joralemon's contention that Nevada contains one of the world's major gold belts is the result of 30 years' active involvement with the state's regional geology. He first suggested the possibility of an arsenical gold belt-tenuously based on two replacement deposits 480 km (300 miles) apart-in his 1949 doctoral thesis of the Getchell mine. In the years that followed, some 18 or 20 arsenical gold ore bodies have been discovered along the lineament Joralemon postulated. In this article, he uses the evidence that he's collected over the last three decades to refine his 1949 thesis. Joralemon's conclusion: A mineral belt containing a billion dollars worth of gold extends the length of Nevada, and a number of ore bodies are yet to be discovered.

Jan 7, 1978

By Thomas MacFarlane

During the last fifteen years the progress made in the science of lithology has been of a very marked character. From being a miscellaneous collection of facts and observations regarding certain mineral aggregates seemingly incapable of systematic arrangement, it has become a most interesting and orderly department of science. The investigators who have brought about this great change have recorded the results of their labors, and placed at our service an extensive and varied literature on the subject. To this I have paid some attention, and partly from studying it,, partly from my own observations, I have wrought out a classification of original or crystalline rocks, which I venture to bring under the notice of the members of this Institute. The practical importance of the subject will be acknowledged when it is considered that rock species are not without their influence on the contents of the mineral veins which intersect them. Besides, the Institute has been doing good service in defining terms in metallurgy, and no doubt in mining and geology we might

Jan 1, 1880

By David J. Dunn, Richard G. Martin

Of many physical parameters critical to design of grinding processes, impact of grinding media is among the most difficult to measure or predict. Yet impact of falling grinding balls, pebbles, or rods accomplishes the fine grinding essential to metallurgical recovery of most important minerals. Unfortunately, the same impacts that break ore fragments deform or crack grinding mill liners. A project was undertaken at Climax Molybdenum Company to measure impact forces in operating ball mills so that they might be used to calculate stresses in liner materials and be correlated with service performance of mill liner alloys. Towards that end, a method of measuring impact forces on ball mill liners using an instrumented grinding ball has been developed. Preliminary tests show that impact forces and contact stresses imposed on bare mill liners are quite high but are greatly reduced by cushioning when coarse ore particles are crushed between balls and liners.

Jan 4, 1978

By Thomas MacFarlane

DURING the last fifteen years the progress made in the science of lithology has been of a very marked character. From being a miscellaneous collection of facts and observations regarding certain mineral aggregates seemingly incapable of systematic arrangement, it has become a most interesting and orderly department of science. The investigators who have brought about this great change have recorded the results of their labors, and placed at our service an extensive and varied literature on the subject. To this I have paid some attention, and partly from .studying it, partly from my own observations, I have wrought out a classification of original or crystalline rocks, which I venture to bring under the notice of the members of this Institute. The practical importance of the subject will be acknowledged when it is considered that rock species are not without their influence on the contents of the mineral veins which intersect them. Besides, the Institute has been doing good service in defining terms in metallurgy, and no doubt in mining and geology we might

Jan 1, 1880

By N. S. Kenny, A. A. Burr

THE purpose of this note is to present evidence that vacancies, which have been produced by quenching from a high temperature, alter the rate of strain-hardening of an hep single crystal. The majority of investigations of the effects of quenched-in vacancies on the yield stress of metals have been made using fee samples in the form of thin wires. However, there is an inherent disadvantage in using such wires to study the effects of vacancies on the rate of strain-hardening of metals because fee wires begin stage II slip either immediately upon yielding or very shortly thereafter. When stage II slip occurs, very rapid strain hardening also occurs, masking the effects of vacancies on the rate of hardening. In this investigation single crystals of magnesium hep were studied since magnesium has only one slip plane at low temperatures and has, therefore, an extensive easy glide region. In addition, the effect of both static and dynamic recovery on the rate of hardening were eliminated by testing in liquid nitrogen. Both forms of recovery occur in hep metals by dislocation climb, which is a diffusion controlled mechanism and is negligible at liquid nitrogen temperatures. Finally, the dependence of the strain-hardening rate on the crystal orientation was eliminated by using the equations of Schmid and Boas.' Variations in the strain-hardening rate could, therefore, be attributed to the presence of vacancies. Single crystals in the form of rods approximately 5 mm in diam and 6 cm long were grown by a modified Bridgman technique from commercial high-purity magnesium (99.97 pet) supplied by the Dow Chemical

Jan 1, 1962

By E. T. Dumble

The domes of the Texas coastal plain are structural features, consisting of bosses or stocks of salt, gypsum or anhydrite, or of combinations of these, intruding into and occurring in connection with broken and uplifted sedimentary beds of Cretaceous and Tertiary age. Some of these domes show on the surface as mounds of greater or less elevation, while others are only known from drilling records. They may be divided into two classes: interior domes and coastal domes. The interior domes include those which occur in a zone 40 to 50 miles in width lying immediately east of the Cretaceous-Tertiary contact, and extending from the Sabine to the Colorado. With a single exception, these domes, so far as now known, occur in approximate alignment with the contact, but at irregular intervals. East of the Brazos, the domes are entirely surrounded by Eocene sediments. The coastal domes are found nearer the Gulf, lying entirely within Neocene territory and stretching from the Rio Grande to the Sabine. They are much more numerous than the interior domes, and, apparently, are ranged along several lines having a general northeast-southwest direction. No domes are known in the Oligocene belt. INTERIOR DOMES The interior domes so far, identified are Butler's, in Leon county, Palestine and Keechi in Anderson county, Brooks and Steen in Smith county, and Grand Saline in Van Zandt. In connection with these interior domes we must also consider the Sabine Peninsula,. of Harris, which is, without question, genetically connected with them. The Palestine and Keechi domes have been described recently by 0. B. Hopkins,1 who gives a clear idea of their corn position and structure. Others have been described at different times, and an excellent resume of the literature is given by De Golyer.2 _

Jan 10, 1918

By C. K. Leith, W. J. Mead

In 1911, we published in the Transactions a brief account of the lateritic alterations of serpentine in eastern Cuba, producing the important iron-ore deposits of the Mayari and Moa districts.' The special feature of that article was a quantitative treatment of the alterations, based on analyses, to show just what had happened in terms of chemical, mineralogical, and physical changes. Professor Kemp has published an interesting account of these ores, containing additional quantitative observations of his own, tending essentially to confirm the nature of the changes that had been worked out.2 His discussion suggests to us the desirability of publishing certain additional quantitative data which were not included in our previous article. This seems especially desirable because quantitative measurements of lateritic alterations are rare, and this particular case may be regarded as typical of a fairly wide range of alterations of this kind. At the time of our examination of Mayari and Moa deposits 29 complete analyses were supplied us by the chemists of the Spanish-American Iron, Co., representing a graded series from the unaltered serpentine rock below to the ore at the surface. These analyses are given in the accompanying table. The mineralogical composition of the ores and rocks is comparatively simple and can be easily calculated from the analyses. In Fig. 1 the mineralogical changes from the serpentine rock below to the lateritic iron ore above, based on the analyses, are expressed in terms of weight, assuming alumina to have remained constant during the alteration. It is not easy by mere inspection of this table of analyses to determine what the progressive chemical changes have been in development of the ore. In order to bring this out clearly, the analyses have been graphically represented in Fig. 2 in such a fashion as to show the progressive additions and losses of substances during alteration.

Jan 1, 1916