Search Documents

By Preston McGrain

Geologic maps are indispensable tools in the modern search for mineral and fossil-fuel resources. They are the first essential step in understanding the lithologic nature and structure of rock units that form the land surface and that lie beneath it. They provide the basic foundation for planning mineral resource exploration programs and form the superstructure from which subsurface investigations are projected. In view of the economic application of such maps, the Commonwealth of Kentucky and the Federal Government entered a formal agreement in 1960 to map Kentucky geologically on a scale of 1:24, 000, or one inch map distance equals 2,000 feet on the ground. A 7. 5-minute quadrangle would comprise the unit map area. A resolution which urged the preparation of a new geological map of the entire State was passed by the Kentucky Society of Professional Engineers in February 1959, and was presented to the Governor of Kentucky, the Legislative Research Commission, Kentucky Department of Economic Development (now Department of Commerce), Kentucky Chamber of Commerce, and Kentucky Geological Survey with a request for support and action. The request was subsequently endorsed and actively supported by numerous civic and professional societies as well as representatives of various facets of Kentucky government, commerce, and industry. Monies to initiate the program were appropriated by the next session of Kentucky legislature; this appropriation was matched by federal funds (Hagan, 1961). Kentucky's state-wide topographic mapping project was completed in 1956, just four years prior to starting the geologic mapping program. The recently completed modern 7. 5-minute, 1:24,000 topographic maps made ideal bases for plotting areal geology. Had they not been available, it is doubtful if a geo- logic mapping program so large and comprehensive could have been undertaken.

Jan 1, 1966

By C. R. King

Most of the acid volcanic glasses such as obsidian, perlite, pitchstone, pumice, and pumicite (volcanic ash) are susceptible to some expansion if suddenly subjected to a suitably high temperature in a properly designed furnace, and subsequently suddenly cooled. Expansion results from the action of chemically combined or dissolved water expanding as a vapor within the softened heated rock particles. This expansion forms countless minute bubbles within the pasty mass of the natural glass particles. If the particles are cooled before these bubbles can escape, the resulting products are cellular, more or less spherulitized glass froths or hollow glass spheres of many types. Chemically, they are essentially aluminum silicates containing about 70 to 75 pct silica, 10 to 16 pct alumina, and 2 to 7 pct sodium plus potassium oxides. They are relatively resistant to attack by acids or alkalies, are resistant to heat up to over 1000°F, and are completely inert to insect or fungus attack.

Jan 1, 1949

By J. Edwin Van Buskirk

For a country that is as important a gold producer as Canada, the return to the gold standard of the major commercial countries of the world during the past five years is of particular significance. To the Canadian gold mining industry, the advantages of the gold standard are a matter of more than theoretical importance. According to economic theory, prices are determined by the relation between the demand for, and the supply of, money. The demand consists of the offering of goods for money; the more goods offered, the greater the demand. The supply consists of the total money available for the purchase of goods. The total supply of goods to be exchanged through the instrumentality of money remaining the same, an increase in the supply of money will, according to this theory, raise prices; conversely, a decrease in the supply of money will lower prices. Let us imagine that everyone in the world suddenly had twice as much money, and that the sum total of all goods remained the same. Is it not obvious that we would pay just double the price for these goods? In Canada today, most people have approximately 50 per cent grea.ter income than in 1913, and the average price for all articles sold in Canada is 50 per cent above those in 1913.

Jan 1, 1928

By T. M. Girdler

IN THESE perilous days of world- wide uncertainty, this Institute and the profession represented by it take on new importance in the economic life of the nation. I have long been impressed by the fact that the objects of the A.I.M.E. are purely professional and scientific. The country has benefited from your honorable tradition of adherence to those objectives over a period of 68 years. The Institute's policy of refraining from controversial matters - has made possible the serious, balanced, and uncolored consideration of the particular problems that come before it.

Jan 1, 1939

By Walter R. Hibbard, Walter L. Finlay

INTRODUCTION THE key feature of the lattice coherency theory of precipitation hardening1-6 is the forced coherence between matrix and precipitate which elastically strains both lattices and is believed to be the major source of strengthening in precipitation hardening. In systems exhibiting age hardening, the atom movements leading to precipitation are not at all extensive and are such as to require the minimum amount of energy to produce the interface; that is, the new lattice forms in such a way as to be as nearly as possible a continuation of the old with a matched, coherent plane at the interface at least during the initiation of the precipitation. The crystallographic sequence whereby regions of the matrix change to the precipitate lattice usually can be resolved into a set of shearing operations.5,6 Conversely, the perhaps novel speculation is made that solution of a second phase is accompanied by shearing movements which are possibly the reverse of the precipitation shearing movements. A basic premise of the investigation reported in this paper is that precipitation and solution shearing movements constitute structural weaknesses which might cooperate with applied stresses to facilitate plastic deformation. Another basic premise of the investigation is that the application of hydrostatic pressure to a precipitation hardening system will significantly alter the degree of disregistry across the matrix-precipitate interface and thereby significantly affect the course of age hardening. Two binary precipitation hardening systems were investigated: 12 pct zinc in aluminum which undergoes transformations, both precipitation and solution, by a simple crystallographic mechanism; and 4 pct copper in aluminum which undergoes a complex transformation in precipitating and dissolving a second phase. The effects of the application of uniaxial tensile creep stress during elevated temperature aging of both systems and of hydrostatic pressure during the elevated temperature aging of 12 pct aluminum-zinc were then investigated. Previous Investigations Van Wert in 1935,7 studied the effect of hydrostatic pressure on the room temperature age hardening of a few precipitation hardening systems. The latter were rather unfortunately selected since none is known to exhibit any marked volume change on aging and the majority were complex commercial alloys the precipitation mechanisms of which are not known. Jenkins, Bucknall and Jenkinson,8 in 1944, applied tensile creep stresses to a complex coppernickel-silicon alloy at various temperatures. The complexity of the alloy and the industrial objective of the work did not permit an appreciable addition to the theoretical understanding of either deformation or precipitation hardening.

Jan 1, 1948

By Cyril Stanley Smith, Earl W. Palmer

A STUDY of the precipitation-hardening of copper steels1 led the authors to investigate malleable iron containing copper, for the low-carbon ferritic matrix in malleable iron should lend itself admirably to precipitation-hardening. It was soon found that in addition to rendering malleable iron susceptible to improvement by precipitation-hardening treatments, copper has another potentially useful effect as an accelerator of graphitization. Brief mention of these effects was given in a general paper by Lorig and one of the present authors2; the present paper gives further details on the graphitization and precipitation-hardening effects only. After the completion of this work a paper by L. Lykkin3 appeared, confirming the authors' conclusions regarding graphitization. MATERIAL USED After some preliminary heats had been made in the laboratory to determine the effect of copper, several castings from commercial air-furnace heats were obtained, and data from these alone are given here. Part of the metal was poured directly and part was treated in the ladle with the desired amount of copper before pouring. Green-sand molds were used, each holding two tensile test pieces of the form adopted by the Malleable Iron Research Institute, or two bars for graphitization studies, 5/8 in. in diameter and 9 in. long, fed through two enlarged sections equidistant from the middle and ends of the bars. Risers of suitable size insured sound castings. Tensile tests were made

Jan 1, 1935

By R. E. Allen

THERE was once a time when a practical oil man would appraise or buy a producing property on the basis of from $200 to $500 per barrel of average daily settled production. Curtailment-has, for the present at least, caused a virtual abandonment of the "barrel -of settled production" as a yardstick of, oil property value and in its place has come the "barrel of allowable production," which, although an artificial thing, is nevertheless now the principal factor governing the rate of ?pay out? or investment return. The potential production of a well, settled or otherwise, is of less importance in determining the present worth of a well than is the rate at which it may be produced. Speaking only of true potential for the moment, it is obvious that of two similar wells having the same potential, the one having the highest rate of allowable production would be worth proportionately more than the one of lesser allowable. The discount factor for deferred return and risk can easily vary the present values of the two wells by as much as 20 per cent when allowable rates are not greatly different.

Jan 1, 1934

By Oliver C., Ralston

THE following data were obtained during Tan exhaustive research into the possibilities of concentrating United Verde massive sulfide copper-zinc-iron ores by flotation. The composition of these ores approximates the following mineralogical analysis: 3 to 15 per cent chalcopyrite; 3 to 11 per cent marmatite (ferruginous sphalerite) ; 47 to 69 per cent pyrite; and 10 per cent quartz. The remainder is usually schist gangue. The sulfide minerals are finely dis-seminated; chalcopvrite and marmatite begin to be liberated on grinding at about 100 mesh, but complete liberation from gangue (pyrite in this case is considered a gangue mineral) is

Jan 1, 1935

By Fearnsides W. G.

The second part of the paper, presented at the Midland Institute of Mining, Civil and Mechanical Engineers' general meeting held in Doncaster on 27th May 1916, addresses the post-Carboniferous and pre-Permian movements which brought about the partition of the area and gave to the North Midland district its individuality as a separate coalfield. As earth-movements of several ages subsequent to the Carboniferous have played a part in the formation of this particular coalfield, the aim is to elucidate the effects which belong to the post-Carboniferous and pre-Permian Period and to disentangle them from those of later date. This is done by comparing the geometry of the folded surface of one of the more important horizons in the Coal-Measures with that of the surface of unconformity which divides the Permian from the Carboniferous rocks in South Yorkshire, Derbyshire, and Nottinghamshire

Dec 1, 1916

By Fearnsides W. G.

The map shows the sites of collieries and important boreholes in the district, with approximate underground contours of the pre-Permian surface of the Coal-Measures and of the Barnsley Bed

Dec 1, 1916

By Fearnsides W. G.

Discussion at the The Midland Institute of Mining, Civil and Mechanical Engineers' general meeting held in Doncaster on 27th May 1916, on the paper published in Trans. I.Min.E., vol.LI, 1916, p.409-448, included oral contributions by Lupton A. on the mechanisms of subsidence and water egress and by Kendall P.F. on the validity and accuracy of the contour extrapolation technique and the effect of major faults, together with the author's response

Dec 1, 1916

By D. K. Crampton

THE object of this work was to obtain and correlate information on effect of internal stress in variously drawn tubes on several properties. Also, a simple approximate method of comparing types of stress distribution in such variously drawn tubes was sought. There is also included some work on comparison of single and polycrystalline materials and effect of different types of operation and preferred orientation. PREPARATION OF MATERIAL A series of tubes was drawn to study the effect of the type and degree of final reduction on various physical properties and the approximate distribution of stress intensity across the tube wall. The material used all came from a single heat of 70-30 brass melted in a regular production Ajax-Wyatt induction furnace. The analysis of the metal as cast was: copper, 70.36 per cent; lead, 0.04; iron, 0.02; zinc, balance. The material was cast in "shells" with 4 in. outside diameter and 3/4 in. wall thickness. It was drawn part way down according to the usual standard mill schedule and then by suitable individual schedules to finish by a variety of types and degrees of drawing to the same final cases in every instance; namely, 0.750 in. outside diameter by 0.080 in. wall thickness. The exact final draws, together with the percentage area reductions, diameter reductions and gage reductions are given in Table 1.

Jan 1, 1932

By F. R. Zachar

IT has always been understood, in northern West Virginia where both the Pittsburgh and Sewickley seams are mined, that pillaring or splitting in the lower Pittsburgh seam could break the interval strata and make mining in the overlying Sewickley difficult or impossible. In some instances, however, mining methods practiced in the overlying Sewickley have reversed the problem, resulting in a shifting of the intermediate layer and destroying valuable acreages of the Pittsburgh seam below. The Pittsburgh seam in this area is, on the average, 102 in. thick. About 18 in. of low-quality head coal are left for roof protection as it is mined. Immediately over the coal are two draw slates, two rider 'seams, and a good hard black shale, locally called black rock, which serves as a permanent roof where draw slates and riders are taken down on certain main haulroads. In most areas mined in this seam in the past the bottom has been satisfactory but soft. However, in areas now being mined by the Christopher Coal Co. in Monongalia County the bottom is very hard and unyielding. The Sewickley seam, lying 85 ft above the Pittsburgh, will average nearly 70 in. in thickness and is overlain by massive shales and sandstones. Much of the seam is mined only down to the "sheep skin," a hard band about 4 in. above the bottom, which is composed of relatively hard shale. Fig. 1 shows a typical cross-section through the Pittsburgh and Sewickley seams in the area being discussed. The thin Redstone seam is not deep-mined but is stripped in some locations where it outcrops. Most of the Sewickley seam in the Morgantown areas has been mined out from 10 to 30 years. There are at present only two large mines and five or six others of small production operating in that seam. Mining systems in the past were generally of the room and pillar type with some full pillar extraction. This seam in the Scott's Run area was operated by as many as thirty or forty different companies at one time, during an era beset with strikes, market failures, and depressions. Most of the barrier pillars along the many main haulroads were abandoned, and blocks of Sewickley coal that would be fully recovered with today's machinery were left unmined when conditions became anything less than favorable. Consequently the mined-out Sewickley is spotted throughout with solid blocks varying in size from 100x100 ft to 200x400 ft and larger. It is these unmined Sewickley blocks surrounded by worked-out portions that have caused transmissions of roof stresses to underlying Pittsburgh mining areas, see Fig. 2, resulting in untold difficulty. As the Christopher Coal Co. operates both the Pittsburgh and Sewickley seams, accurate maps of workings in both seams are readily available and are regularly consulted. The first Pittsburgh squeeze attributed to overlying Sewickley blocks occurred in the Arkwright mine, where a shuttle car crew was developing a section consisting of seven panel headings. These entries were being driven in solid coal 3400 ft from the nearest worked-out Pittsburgh area. As mining advanced it was noticed that certain ribs began to slough and certain areas to show signs

Jan 1, 1952

Results of flotation tests on lead-zinc ore from Broken Hill, N.S.W., confirmed that flotation at pH 9 in the presence of cement gave poorer metallurgical results than flotation at pH 7. Additions of 2 kg/tonne wood raspings [e.g. blackbutt (Eucalyptus pilularis), blue gum (E. saligna), brushbox (Tristania conferta), or turpentine gum (Syncarpia laurifolia)l had little effect at pH 7 but greatly accentuated the deleterious effect of cement at pH 9. This was shown to be caused by e:xtractives (e.g. polyphenols and carbohydrate materials) derived from woods at pH 9. The proportion of extractives, as shown by DV absorbance spectra, increased with increase of pH and was affected by various salts.Additions of 1 kg/tonne Al2(S04)3.16H20 when cement or cement and wood were present showed that metallurgical results obtained by flotation were then very simHar to those in the absence of cement or wood or both. This was ascribed to lower pH values in the presence of aluminium sulphate and possibly to specific chemical effects.Additions of aluminium sulphate appear to offer an economic solution to the problem of treatment of ores contaminated with cemented fill at Broken Hill.

Jan 1, 1974

By M. A. Hunter

THIS paper gives the results of an investigation of the specific resistance and temperature coefficient of the electrical resistance of nickel and its important alloy, monel metal. For most of the pure metals, the temperature coefficient of resistance is approximately 0.0004 per degree centigrade at 2.0° C. Nickel and iron, however, are exceptions. This property is important as it gives us good material for the construction of thermometers and other instruments involving electrical control. A summary of information on this subject has been published by the Bureau of Standards.1 The present experiments antedate this publication by several years and as the information obtained is not contained in it, the results of the experiments are published as additional information. ELECTRICAL PROPERTIES OF PURE NICKEL It is generally conceded that the lowest values for electrical resistance are obtained in the purest metal. In the case of nickel, the best material obtainable is electrolytic nickel, which contains approximately. 99.80 per cent. nickel, 0.15 per cent. iron, and 0.05 per cent. copper. Any cobalt that may be present is included in the nickel figure. If the electrolytic sheet has been deposited without intermission, it is possible to cut a section from the sheet and roll it into wire without melting. By this means a nickel wire may be obtained that is uncontaminated by any of the impurities always taken up by nickel during melting.

Jan 5, 1922

By G. M. Swinkels

It is generally accepted, that oxygen is a necessary reagent for the flotation of galena with xanthate. Recent measurements have shown (1) that under plant conditions oxygen may be in a short supply to the extent that it limits the rate of flotation. Thus, it becomes important to define the exact role of oxygen and establish a model for the rational design and control of flotation separations, involving oxygen as a reagent. All theories or, the flotation of galena assign oxygen the role of an oxidant. However, they disagree on a number of questions: 1) Is the galena or the xanthate being oxidized? 2) Is a lead dixanthate or dixanthogen the actual collector? 3) Is the oxidation process in which oxygen participates of a chemical or an electrochemical nature? The last question arises from the observation (2) that an anodic bias as well as oxygen will make a galena surface hydrophobic in the presence of xanthate. Theories which are based an the premise that the influence of oxygen is of an electrochemical nature offer elegant models of galena flotation. However, full advantage has not been taken of available electrochemical techniques to discriminate between theories and this is the area towards which this research has been directed (3).

Jan 1, 1970

By D. Harrington

For many years the Federal Bureau of Mines-in cooperation with other agencies-has been making investigations and compiling and publishing reports and statistics on accidents in the various branches of the mineral industry.4 Its assistance has been enlisted also in health, safety, and ventilation problems' incident to the driving of many large tunnels in the United States in recent years. As part of this work the Bureau has compiled considerable statistical and other information on accident experience in the tunneling branch of the heavy-construction industry. It has always been difficult to obtain up-to-date information on tunneling methods and tunnel accidents. Published accounts of tun¬nel construction furnish much interesting material of engineering, historical, or fiscal value, but usually little or no attempt is made to discuss and critically analyze the means taken to preserve the health and life of employees.

Jan 1, 1941

By O. B. Ellis

Although thousands of tons of stainless steel have been used successfully for many types of equipment, there have been few cases of failures due to the phenomenon described as stress corrosion cracking. During the past seven years only six cases of such failures have been drawn to our attention and investigated in the Research Laboratories with which the author is associated. These failures oc¬curred in two coffee urns, two wool con¬ditioning units, one dyeing machine, and another in a part of a steam-jacketed stock pot. In each case the equipment failed in a comparatively short time after exposure to conditions of high humidity at tempera¬tures in the range of 100 to 200 F. The failures in all cases were characterized by general embrittlement and cracking of the stainless steel, with only slight indications of general corrosion except at the cracks. The first failure of this type was a coffee urn returned for investigation in 1937. The top and bottom sections showed a general corrosive attack and embrittlement and cracking of the stainless steel. The chemical analyses of these sections were as follows:

Jan 1, 1945

By I. H. Wong

The large diameter caisson foundations and their construction methods for three 50 to 60 storey high buildings in Singapore are described. The caissons are 5 m to 8 m in diameter and 40 m to 100 m deep, excavated either by hand or mechanised excavators or by drilling and blasting. Performance of the 50 storey DBS Building is described.

Jan 1, 2010

In common with general experience in the iron-making industry overseas, Australia has in recent years suffered a deterioration in the physical quality of her iron ores in their suitability as a direct blast furnace feed. The increasing amounts of fines and the more friable nature of lump ore, especially in the ore from the Cockatoo Island deposits in Yampi Sound, Western Australia, have focused attention on problems of ore preparation and agglomeration, particularly sintering.Although very small pilot scale Dwight-Lloyd type sinter machines were operated at the steel-making centres at Newcastle and Port Kembla during World War II, no sizeable capacity was installed, so that ore was charged to the blast furnaces almost entirely unscreened, and the resultant flue dust was stockpiled.Towards the close of the war, the pilot plant at Newcastle was replaced by a small machine, adjacent to the flue dust stockpile, with a rated capacity of some 20 tons per hour. After approximately five months of part-time operation, this plant was closed down in January, 1945. Production was not resumed until December, 1950, when, due to a temporary ore shortage, it was decided to supplement available ore with sinter produced from the large flue dust stocks of about 300,000 tons. In spite of mechanical and process difficulties, inherent to the design of the plant, operation was continued on a two-shift basis, with several shutdowns for extensive overhaul and plant alterations, until September, 1954, when production was put on a three-shift basis. Addition of Yampi ore fines to the sinter machine burden was not commenced...

Jan 1, 1957