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By Philip D. Anderson, Ralph Hultgren

Heat contents of extremely pure iron were measured over the range 300"to 1433"K, using a diphenyl ether calorimeter. Results from three samples containing widely differing impurities agreed with one another and with Previously reported results at higher temperatures (1184 ° to 1809°K) by Olette and Ferrier. From these data a table of heat contents of iron has been Prepared which is believed to be more accurate than those previously available. CP values have been derived which are consistent with these heat contents, with the best experimental Cp data, and with the thermodynamic conditions of equilibrium between bcc and fcc iron. The opinion is expressed that low-temperature extrapolations of presently known Cp values for y-Fe are not reliable. It would seem that the thermodynamic properties of iron, which is by far our most important metal, should have been well established long ago. This is not the case, however. As discussed by Olette and Ferrier,' there is objection to every earlier heat content measurement. While the best true Cp determinations agree well at temperatures below the Curie point, there is wide divergence at higher temperatures. Several investigators have examined available data and attempted to calculate thermodynamic functions for iron that are consistent with the two equilibrium temperatures of bcc and fcc iron. The two primary efforts were those of Austin' in 1930 and Darken and smith3 in 1948. The recommended values differ considerably; integration of Austin's Cp values leads to a heat content at 1100°K which is 300 cal per g-atom higher than the value recommended by Darken and Smith. The compilation of Fisher4 in 1949 was based on the selection of Austin. In 1956, Weiss and Tauer obtained yet another set of values by resolving Cp values into components due to dilation, lattice vibration, electronic excitation, and magnetism. The magnitude of contribution by each component and its dependence on temperature was estimated by semiempirical means. Their values are not self-consistent in that they do not form smooth curves when plotted vs temperature; moreover, their calculations cannot easily be repeated since they do not give the values of some of the parameters used. Clearly, experimental values for iron were in a most unsatisfactory state. The presently described measurements of the heat content of iron were therefore undertaken, covering temperatures as high as 1433°K. While the work was in progress, the high-temperature (1193" to 1789"K) heat content measurements of Olette and Ferrier' were published; in the region of temperature overlap the present results agree with Olette and Ferrier well within experimental accuracy. It is believed that the present results, combined with those of Olette and Ferrier, provide for the first time a reliable set of heat contents of iron from room temperature to the melting point. From these data, guided by available Cp measurements, it proved possible to derive Cp, entropy, and free energy function values for @-iron from room temperature to the melting point, and for y- iron in the temperature region of its stability. Exhaustive study led to the conclusion that extrapolations of y-iron functions to room temperature were not reliable enough to be useful; hence these have been omitted from the tables. EXPERIMENTAL Materials. Three samples of extremely high purity iron from different sources, containing widely different impurities, were measured. The first of these, designated "Chipman", was kindly supplied by Dr. K. K. Kelley of the U. S. Bureau of Mines from a lot which was made many years ago by Dr. John Chipman of the Massachusetts Institute of Technology. The second, designated6'Teddington", was supplied by the National Physical Laboratory, Teddington, England, from a lot zone-refined by them. The third sample, designated "Irsid", was supplied by the Institute de Recherches de la

Jan 1, 1962

By James Douglas

As the operation of light railroads is important to the mining industry, the following statistics of the Arizona Southeastern Railroad may be of interest. When the traffic of the Bisbee copper-mines reached 20,000 tons per year the necessity of better transportation than that afforded by eighteen- and twenty-horse and mule teams became imperative on the score of both cheapness and convenience. Before deciding on the construction of a railroad, the Copper Queen Company made a thorough experiment in transportation

Jan 1, 1899

By E. S. Leaver

THE amount of gold that occurs in a ton of milling ore from most of the large-scale copper mines is so small that unusual care and special attention are necessary to recover it. In some cases the gold is not considered important enough to warrant daily assays of the various products. Considering the large tonnage of copper ores that are now concentrated by flotation, as computed in a recent review, the gross gold content is surprisingly large, probably amounting to over 10 million dollars per year in the United States. The indications are that in many of the copper-milling operations with gold content under $1 per ton, only 50 per cent. of the gold is recovered in the flotation concentrates. Lime is generally used as a depressant for pyrite in the flotation circuit. The authors have shown that high lime or a solution high in calcium ions is also a depressant for gold. Their experiments on several well-known ores show that by careful regulation of the alkalinity of the mill solutions, a higher flotation recovery of the gold can be obtained, together with equally good copper recovery in a good grade of copper concentrates. In cyanidation for the recovery of gold, the best accepted practice demands that the mill solutions be tested and regulated by simple chemical reactions at definite periods during treatment or with each change in the treatment. It is similarly important for the recovery of gold that the solution in the flotation circuit be analyzed for calcium ions at regular periods and at each step in the flotation practice. The lime should be added when and where needed and not in excessive amounts at the head of the mill.

Jan 1, 1931

By T. Glen Heslop, Dennis H. Laubscher

INTRODUCTION In all cave mining operations waste is drawn mixed in the ore, hauled, hoisted and milled. This waste usually contains some mineral which partly covers some of the costs of mining and milling it, but it still re- presents a loss of profits as the production rate from the mine is matched to the mill capacity - every tonne of waste milled replaces a tonne of profitable ore. Draw control aims to reduce the amount of waste drawn and to increase the amount of ore recovered. It is also used to regulate the grade of ore flowing to the mill and in block cave blocks to prevent potential stress build- up on the major apexes above grizzly drifts. This paper summarises what has been learnt about draw control in the forty years that cave mining methods have been used in the three largest underground chrysotile asbestos mines in the southern hemisphere. The four mining methods to which draw control has been applied are: a. Block caving. b. Shrinkage with overburden caving. c. Sublevel caving. d. Open stoping. Open stoping has been included because on a number of occasions severe falls from the back and side of these open stopes have occurred. Without full records of where and when ore is blasted, when and how much ore has been drawn from each of the drawpoints, it would be impossible to analyse the migration of ore and fallen waste in the stope. Several problems peculiar to chrysotile asbestos ore bodies affect the practice of draw control. Heterogeneous fragmentation, cavities, side pressures and the interaction of stresses in the caved ore affect the migration of ore under draw. Fibre is normally not developed uniformly throughout the ore bodies, values vary from place to place but there is usually a general decrease upwards and the hangingwall contact is an economic limit. The immediate hangingwall rock frequently looks like the ore body hostrock and is difficult to recognise in a drawpoint, and cannot be used as the marker for stopping draw. During caving or shrinkage, a large proportion of fibre becomes detached from the host rock and re- ports in the fines, which migrate differently to the larger rocks. The fines are not sticky, and flow easily if loose and dry, but compacted, the fibre and rock fines con- solidate the ore. During draw the proportion of fines in the ore varies considerably, as fines either flow relatively freely between the large rocks or become trapped and compacted above large rocks or hangups. This creates a large sampling error in drawpoint grade assessments, whether done visually or by bulk sampling, unless the assessments are done frequently. The method of draw control used is to regulate the draw rate in an attempt to lower the ore-waste interface as evenly as possible, and to finally stop working the drawpoint when a calculated tonnage has been drawn.

Jan 1, 1981

By H. W. Page

Petroleum requirements since V-J day have been appreciably higher than predicted. Foreign operations now exceed maximum wartime levels by about 14 per cent. Domestic operations since V-J day have averaged 92 Per cent of the wartime peak. In spite of maximum foreign refinery runs, large exports of all products, except residual fuel oil, are necessary to meet foreign demand. During the next few years it is expected that foreign operations will continue at capacity, including new installations, but that, because of increases in foreign demand, exports will continue at about their present level. Domestic operations will increase during this period and crude production probably will exceed maximum efficient rates. Even after 10 years some exports probably will be required, but eventually these will be supplanted by increased output of foreign refineries, except for small tributary exports. The increase in domestic requirements will exceed the decline in exports. Unless findings of crude oil exceed present expectations, the increasing demand will be met by increased imports and synthetic methods-—such as the Hydrocarbon Synthesis Process for conversion of natural gas and coal to gasoline and distillates. Catalytic cracking installations will increase as crude availability decreases. This will help to meet the increasing demand for gasoline but will intensify the domestic shortage of residual fuel oil. Eventually larger imports will be required to satisfy the demand for this product. Introduction Under the pressure of the wartime period, there was time only occasionaly to look ahead in anticipation of what the postwar era held for the petroleum industry. Perhaps the general expectation was that a rather pronounced decline in the level of industry petroleum operations would take place shortly after the end of the war, with the impact felt mainly on the economy of the United States- It is of interest now, nine months after V-J day, to take inventory of the near-term situation and see what significant forces are at work. With this as a starting point, it should be possible to engage in something more satisfactory than pure speculation concerning trends in the immediate future and 10 to 20 years ahead. Present and Near-term Situation During the nine-month period following V-J day, foreign crude oil production and rebery operations have actually increased the These activities were at maximum capacity on V-J day but the continuation of drilling programs, the completion of new and rehabilitated refineries and of transportation facilities during the Past nine months have increased the foreign capacity. This added capacity has been fully utilized. Foreign crude oil production in May 1946 is about 14 per cent higher than during July 1945 and refining operations some 12 per cent higher' During the same period there has been a falling off in similar activities within the

Jan 1, 1947

By H. W. Page

Petroleum requirements since V-J day have been appreciably higher than predicted. Foreign operations now exceed maximum wartime levels by about 14 per cent. Domestic operations since V-J day have averaged 92 Per cent of the wartime peak. In spite of maximum foreign refinery runs, large exports of all products, except residual fuel oil, are necessary to meet foreign demand. During the next few years it is expected that foreign operations will continue at capacity, including new installations, but that, because of increases in foreign demand, exports will continue at about their present level. Domestic operations will increase during this period and crude production probably will exceed maximum efficient rates. Even after 10 years some exports probably will be required, but eventually these will be supplanted by increased output of foreign refineries, except for small tributary exports. The increase in domestic requirements will exceed the decline in exports. Unless findings of crude oil exceed present expectations, the increasing demand will be met by increased imports and synthetic methods-—such as the Hydrocarbon Synthesis Process for conversion of natural gas and coal to gasoline and distillates. Catalytic cracking installations will increase as crude availability decreases. This will help to meet the increasing demand for gasoline but will intensify the domestic shortage of residual fuel oil. Eventually larger imports will be required to satisfy the demand for this product. Introduction Under the pressure of the wartime period, there was time only occasionaly to look ahead in anticipation of what the postwar era held for the petroleum industry. Perhaps the general expectation was that a rather pronounced decline in the level of industry petroleum operations would take place shortly after the end of the war, with the impact felt mainly on the economy of the United States- It is of interest now, nine months after V-J day, to take inventory of the near-term situation and see what significant forces are at work. With this as a starting point, it should be possible to engage in something more satisfactory than pure speculation concerning trends in the immediate future and 10 to 20 years ahead. Present and Near-term Situation During the nine-month period following V-J day, foreign crude oil production and rebery operations have actually increased the These activities were at maximum capacity on V-J day but the continuation of drilling programs, the completion of new and rehabilitated refineries and of transportation facilities during the Past nine months have increased the foreign capacity. This added capacity has been fully utilized. Foreign crude oil production in May 1946 is about 14 per cent higher than during July 1945 and refining operations some 12 per cent higher' During the same period there has been a falling off in similar activities within the

Jan 1, 1947

By R. G. Hawthorne

This report is concerned with fluid displacement in porous media, in those cases where viscous and gravitational forces control the displacement. Such a system would usually be found in a sand body of large physical dimensions such as an oil reservoir, although it is possible to create such a system in the laboratory. It is shown that the position of the fluid interface can be predicted by numerical calculations using a basic idea presented by Dietz. Fluid flow is considered in a vertical plane in a homogeneous, porous medium of sufficient thickness that the capillary transition zone is small in comparison with the total reservoir. A theory developed by Dietz' is used to make numerical calculations of the position of the fluid interface. The results for several conditions are compared with scaled model experiments. The results show that, for gas drive in a reservoir of steep dip, a relatively low flow rate can displace large volumes of oil before gas breakthrough. On the other hand, water injection at favorable mobility ratio and low dip may show best performance at high rates. Water tends to underride the oil and, given sufficient rime, will break through without much oil displacement. For certain conditions, which include relatively low flow rate, the interface is a straight line and its behavior is simple to calculate. At higher flow rates, the interface is unstable, and a numerical solution was programed for an automatic computer. In general, good agreement is shown between the fluid model and the computed results so long as gravitational forces have control. For a water drive at very unfavorable mobility ratio, many small water fingers appear. These viscous fingers are not controlled by the relatively small gravitational forces. When viscous fingering becomes the controlling factor, the mathematical model is oversimplified, and results do not check the fluid flow model. INTRODUCTION Present methods of reservoir analysis depend upon certain simplifying assumptions to obtain mathematical descriptions of practical use. Material-balance methods (Muskat2 or Tarner2) assume uniform fluid saturations in the entire reservoir, or in a few subdivisions of the reservoir. An unsteady-state flow calculation by West, er at considered pressure and saturation changes in flow to a well during solution gas drive, and neglected gravity effects. Results showed only a 4 per cent difference for ultimate oil recovery by the Muskat method, even though the case chosen for study was one in which unsteady-state effects should be high. The Buckley-Leverett5 method commonly assumes a one-dimensional flow system. It is applicable at high flow rates where viscous forces predominate over gravity forces. Simultaneous, parallel flow of the two fluids is assumed, and the concept of a fluid interface is not introduced. Permeabilities to each fluid for a given saturation must be known. The method is not applicable for a two-dimensional system where cross flow becomes possible. Less well known is the displacement equation derived by Dietz. This method is designed for two-dimensional flow systems and assumes a definable fluid interface within the porous medium. Dietz showed that, for a range of low flow rates, the interface would be stable. straight and at an angle of inclination which could be simply calculated. At a certain critical flow rate, the calculated interface tilt would equal the formation dip. For higher flow rates, a finger of displacing fluid would invade the displaced fluid. Dietz indicated that his method applied only to macroscopic reservoir behavior, while the Buckley-Leverett method applied to the small transition zone at the fluid interface. The examples worked out in this report are based on the fluid-displacement theory of Dietz. It is shown that the Dietz theory may be used to derive equations analogous to the Buckley-Leverett equations. In contrast to the Buckley-Leverett method, flow is considered in a plane rather than being limited to a line. Rather than a frontal advance, the movement of a fluid interface is followed. For flow rates substantially exceeding the critical rate and for high viscosity ratio, many fingers of invading fluid occur-—rather than the single finger assumed by Dietz. On the other hand, so long as some gravitational influence remains, the flow is not entirely parallel to the bedding planes as assumed by Buckley and Leverett; therefore, both methods fail to give an adequate descrip-

By C. David Mann

Metal prices continued to improve in 1964, resulting in the opening of new mines and re- activation of old ones. Larger and deeper shafts are being bored. At the AEC's Nevada Test Site, a 72-in. diam shaft is being bored to 3200 ft. In New Mexico a 1650-ft shaft was bored with a 48-in. bit, then reamed to 124 in. to 935 ft, and 102 in. to 1650 ft. Deviation was only 26 in. In California a shaft sinking machine has been developed which combines drilling and mucking equipment into one mobile, integral unit.

Jan 2, 1965

By Charles Parmelee

When Professor Silliman made his first examination of the newly-discovered Pennsylvania rock oil in 1859, he noted that different rates of heating produced different results in fractionation—longer heating produced larger percentages of light fractions. In 1862, it was found that when petroleum vapors are condensed in the still crown and dropped back into the hot liquid, the result of the distilling operation is materially modified. These early dates mark the beginning of what is called cracking petroleum and is explained as separating the component parts of the hydrocarbon molecules into more and smaller groups of the same elements. The phenomena were utilized for the next 30 years to increase the yield of burning oil. The procedure was that regularly practiced today in dry or destructive distillation. Considerable scientific study was given to the subject from 1862 to 1905, and a number of patents were obtained, but the work done was not continuous or intensive until about 1905, when the increasing demand for gasoline attracted attention of petroleum refiners to the possibilities of cracking. The first equipment built and operated essentially for cracking petroleum on a large scale was placed in successful operation in 1912. The commercial practice is, therefore, less than 15 years old. Comprehensive intense study of the controlling factors during this period has resulted in rapid increase in our knowledge, and material improvement has been made in the practice of the art. It is the purpose of this paper to outline briefly the state of our knowledge and to suggest some of the questions which are attracting attention of researchers at the present time. The major purposes for which petroleum hydrocarbons, including natural gas, are or have been cracked are: 1. To obtain products used to increase the heat value and illuminant content of artificial gas. 2. During the World War, to increase the supply of toluol. 3. To increase the amount of products capable of conversion into industrial chemicals. 4. To produce pure carbon.

Jan 1, 1927

By Carl H. Beal

The most important factors that should be given consideration in the valuation of oil lands are: (1) the amount of oil the property will produce; (2) the amount of money this oil will bring (based upon the future prices of oil); (3) development and production costs; (4) the rate of interest on the investment; (5) the retirement or amortization of invested capital; and (6) the salvage or "scrap" value of the equipment when the property is exhausted. These factors are of varying importance and some of them may not enter all valuation problems, but most of them should be given consideration in any valuation even though only a rough estimate of the value of the property is desired. The value of a property may be changed over night by the completion of important test wells, by the sudden water flooding, or by a change in the price of oil. The best a petroleum engineer can give is the value of the property under the conditions existing at the time the appraisal is made with a fair forecast of future action of the wells and of the price of oil. Our experience in the scientific valuation of oil lands is not broad and there is very little published information on the subject; it, therefore, becomes necessary in studying such problems to form comparisons with the factors involved in the valuation of mines—the closest parallel. One of the reasons for the lack of substantial progress in oil-land valuation methods has been the necessity of making an estimate of the future production of the oil property to be valued. Oil men and accountants have not generally conceded that such estimates could be made with any degree of accuracy. It has been shown, however, in several recent publications that with certain data available reasonably close estimates can be made. The accuracy of an appraisal depends chiefly on the accuracy of the estimates of future production and of the future price of oil. The accuracy of the former is sometimes necessarily based on geological inferences. Geology is not an exact science and geological data in connection with oil production cannot always be mathematically evaluated.

Jan 1, 1921

By G. S. Hume

Activity in geological exploration and drilling continued in Canada in 1945 at about the same rate as in the previous year, but with disappointing results as far as new production is .concerned. Both in the foothills and on the Plains of Alberta, however, there are wildcat wells that have either given encouraging shows or some production, which are very important in relation to future developments. The normal decline of Turner Valley, the largest producing field in Canada, has continued, and this decrease has not been offset by new discoveries. In addition, the closing of the Canol pipe line on March 31, 1945, isolated the Norman Wells field in the Mackenzie River valley, and the outlet at present. is confined to supplying the relatively small local requirements. This

Jan 1, 1946

By Lester C. Uren

Tars paper reviews the industrial trends and changes in educational concepts that have led to the development of the modern petroleum engineering curriculum. A trend toward emphasis on engineering fundamentals is noted. While most universities are committed to the traditional four-year engineering program, it is agreed that more than four years is necessary for academic preparation of the petroleum engineer in all phases of his profession. The author proposes a coordinated program of undergraduate and graduate training that will permit of adherence to the general pattern of the present four-year engineering course, with provision for extension of the program into specialized graduate courses of professional character. In the latter, emphasis may vary with the interests and objectives of the individual student. A specific undergraduate curriculum is proposed in which upward of 80 per cent of the available time is devoted to engineering fundamentals. A broad survey of the professional field is afforded in courses grouped in the third and fourth undergraduate years, but detailed treatment of the professional aspects of petroleum engineering is reserved for the graduate program. INTRODUCTION Of necessity, engineering curricula must ever be changing to reflect the new techniques, the changing concepts that are presented as the engineering industries develop and unfold. Particularly is this true of the younger engineering curricula representing comparatively new and rapidly changing industries such as the petroleum industry. Institutions that planned their petroleum engineering curricula a decade or two ago now find that the petroleum industry has become vastly more technical in its requirements. En¬tirely new methods and techniques have come into vogue and must be given place in the curriculum, and some of these are of a character that demands changing emphasis in the fundamental preparatory subjects. College and university faculties cannot complacently assume that curricula in this field that were considered appropriate 10 or 20 years ago still reflect the needs of the industry that they are designed to serve. If they do, their graduates will be poorly equipped to meet the requirements imposed upon them by a rapidly changing industry. Perhaps it is not too much to expect academic authorities to anticipate the trends of industry and equip their graduates with what they will need to attain leadership 10 or 20 years after graduation. Whether or not this desirable objective is possible, there is no excuse for allowing curricula to fall behind the current needs of industry. DURATION OF CURRICULUM The majority of our engineering schools and colleges still adhere to the four-year curricula and there appears to be a definite sentiment among many engineers engaged in industry that work should be so planned that the engineering student may secure the essential academic preparation for his profession in a terminal four-year program. Yet, in recent years, it has become increasingly apparent that four years of

Jan 1, 1941

By Henry M. Howe

IN discussing the classification of iron to-day, we are to leave out of consideration the general division into non-malleable or cast iron and malleable iron, as to the adequacy of which no question has been raised; and to confine ourselves to the subdivisions of malleable iron. This has been classified, according to the extent to which the properties imparted by carbon are present (viz., resilience, hardness, strength„ and, above all, the capacity for being hardened by sudden cooling from a high temperature), into (1) wrought iron which cannot be hardened, and (2) steel which can be hardened; and this classification I shall, for briefness, term the carbon classification. Until within a few years all authorities, both metallurgical and general,, have concurred in explicitly recognizing the carbon-given qualities, and preeminently the capacity for being hardened, as the essential qualities of steel ; this is laid down with clearness by every writer on the subject. For several years this old classification has not been sufficient to, meet all our needs, since the genius of Bessemer, Siemens, and, I may add, Holley, has produced wrought iron which has been perfectly melted, and thus freed from certain mechanical adhering impurities. This causes what we call homogeneousness for want of a better word, and gives rise to many important qualities which the old wrought iron had not;. qualities universally recognized, though not readily described. I shall, for briefness, style them the fusion qualities, and a classification based on them., a fusion classification. These qualities render the new product so vastly superior, for most purposes, to the wrought iron formerly known, that it is neces- * This paper was read in opening the discussion on the motion to adopt the report of the International Committee on the Nomenclature of Iron and Steel. At the conclusion of the discussion the resolutions on page 44 were adopted.

Jan 1, 1877

By R. W. Titshall

WHAT IS SAMPLING? We are all involved in sampling almost every day of our lives, by tasting, feeling, or smelling. Most raw materials, food products or manufactured items are sampled several times at various stages of the production process before a commodity of suitable quality can be produced. Data obtained from sampling is used in establishing price, quality control, allocating production costs, or overall process efficiency. The area of sampling outlined in this article is the collection of a small quantity of material from large continuous bulk flows of solids and slurries. The concern in obtaining the sample is that the material obtained is truly representative of the main flow in every respect. The methods and equipment outlined are for the collection of a manageable sample. The sample has to be analyzed in a laboratory to determine its characteristics and compliance to set standards. SELECTING A SAMPLING SYSTEM When selecting a sampling system, it is essential to define the requirements, as to what the actual sample obtained will be used for and what degree of precision is required. Determine whether or not the system has to comply with any set standards such as A.S.T.M. (American Society for Testing and Materials) which have established methods for collection of a gross sample of coal. Sampling which is done for in-plant or process control is not generally governed by set procedures, but similar care should be taken during the selection process so that when the equipment is put into service it will operate reliably and produce a sample which is truly representative of the total material lot or consignment.

Jan 1, 1982

BECAUSE you cannot always proceed by the ordinary pathway since you sometimes find yourself in a place where you cannot have all that you might need or wish, it often happens that it is necessary to know how to recognize and understand your materials well, in addition to having them well disposed, and to know how to use your, ingenuity in arranging a mould., Furthermore, things have a great diversity among themselves, and it is not possible to give a particular rule for all. But if you have a certain broad fundamental knowledge when you have need of many things, the ingenuity awakens and supplies its needs by imitation. Now, because I have thought that you had not hitherto had the slightest shadow of knowledge of what I have described in this treatise of mine, I have expanded and narrated things in greater detail than perhaps I might have done. For this reason I have also decided that I wish to tell you of several methods that can be used if you wish to mould, especially in making an intaglio* for a relief, t or in making another intaglio in bronze from either an intaglio or a relief. And I will tell how every relief reduces, itself from convex to concave and also how the relief is made from the intaglio. These works are first made of plaster or pastes or some other liquid thing that is soft when moulded and becomes hard either by drying out with heat or by shrinking with cold, such as tragacanth, plaster of Paris, sulphur, lead, wax, or similar things. And, in conclusion, we describe the method of making an intaglio from a solid. In making an intaglio you must first consider whether it is a large or small thing, figure or foliage, whether it is in demi- or bas-relief, and whether it is a thing that projects from the mould wholly or in part.

Jan 1, 1942

By Fredrick C. Kruger

Anthropological diggings have revealed that the American Indians carried on intertribal trade in flint, obsidian, ochre, and other mineral commodities, indicating that mining was practiced before the arrival of the white man from Europe Carbon datings from the native copper pits on Isle Royal and Keweenaw Peninsula, Michigan, have yielded dates as early as 5555 BC for this mining. As early as Pliocene time, Eolithic-man fashioned artifacts of stones probably found on the surface, but by late Quaternary, Neolithic man was sinking shafts and mining underground for flint. Because placer gold was easily recognized and easily worked, it was used for ornamental purposes by nearly all cultures before other metals were discovered The Chaldeans hammered copper objects approximately 4500 BC and copper was used in India and China about 3000 BC. An ancient trail from the Nile to the Sinai led to the mines of copper and turquoise Paintings and bas-reliefs of Egyptian tombs dating around 3000 BC depict maps, mining, and smelting in this area. It is interesting that despite this widespread and long history of mining, Agricola records that the first mining laws were developed by the Greeks at Laurium about 700 BC. All of the base metals are known to have been produced in small quantities during the Colonial period in America, but perhaps the first commercial production was the iron ore shipped from Virginia to England in 1608, followed by lead in 1621. Among the earliest companies formed in America that still survive (according to the standard reference yearbooks), were: the Jackson Mining Co., predecessor of Cleveland-Cliffs Iron Co. on the Marquette Range, Michigan, in 1844; the Sussex Zinc and Copper Mining & Manufacturing Co., fore-runner of New Jersey Zinc Co. in 1848 (although the Franklin-Sterling body was discovered in 1640); the five companies, Pittsburg and Boston, Quincy Mining, Pewabic, Huron Mining, and Minesota all formed in the decade (1844-1855) that followed the rediscovery of Keweenaw copper, were combined into Calumet and Hecla; and Vermont Copper Mining Co. in 1853 Although southeast Wisconsin lead-zinc was discovered in 1690, Mine La Motte in southeast Missouri in 1720, placer gold in California in 1848, Comstock Lode in 1859, Leadville in 1860, Cripple Creek in 1891, no surviving companies of those early mining periods exist. The first strong producer in the Mississippi Valley was St. Joseph Lead in 1864; Homestake and Pickands-Mather, were formed in 1877, Phelps-Dodge in 1881; Pittsburgh Reduction, the predecessor of Al-

Jan 1, 1976

By F. M. Simonds, E. Z. Burns

The Rawley property is located in the Kerber Creek mining-district, Saguache county, Colorado, at an elevation of 10,600 ft. (See sketch-map, Fig. 1.) Ore was found in this vicinity as early as 1880, and claims covering a large area were located and in many instances patented. The ores, however, being of comparatively low grade, and the nearest railway station, Villa Grove, being some 20 miles away, it is extremely doubtful whether any considerable amount of ore was ever handled at a profit. It is safe to say that several hundred thousand dollars were spent (a large part in building mills) previous to 1902-03. About that time a very capable promoter gathered together a group of these claims and interested some New York people, who had had no previous mining experience, in the purchase of these claims. Following the organization of a company, this promoter became General Manager. As often happens under such conditions, the first step was to erect a mill to treat 100 tons per day. It may not be fair to this enterprise to say that the failure which followed might have been foretold, simply on general principles, but this much is certain—the water supply fluctuates in the course of a season through a wide range and for a considerable portion of the year was inadequate to run this mill at capacity. Further, it is currently reported that some of the mill foundations were placed on ice. However true this statement may be, it is a fact that, when first inspected by us, many of the belts in the mill were held on'their pulleys by means of idlers. A shut-down followed, with a material re-adjustment of interests, at which time we became consulting engineers for the company.

Jan 1, 1914

By Adam L. Wesner, A. C. Richardson

This paper describes the development of a continuous float-and-sink process to produce coal low enough in ash content to be suitable for production of electrodes. The cleaned coal had a combined iron and silicon content of 0.239 pct. The efficiency of recovery was 84 pct. DURING World War I1 the demand for electrode carbon was greater than could be met by the supply of petroleum coke available for this use. It was believed that coke made from an extremely low-ash coal might be a suitable substitute for petroleum coke. Requirements for electrode carbon to be used for the production of aluminum are that the silicon plus iron content shall be not more than 0.14 pct of the coke. However, during the period when petroleum coke was in short supply, it appeared that relaxations of the specifications might be allowed to permit 0.4 pct iron plus silicon in the coke. For this work, the specifications were that the coal should contain less than 1 pct of ash, and the combined iron and silicon content of the coal should not exceed 0.28 pct. Heavy-liquid separations made on a number of coals showed that if certain size fractions of some coals Were separated at low specific gravities the resulting float products would meet the required specifications. The objective of this work was to develop a continuous, commercially feasible process for producing low-ash coal. After consideration of various processes, the method chosen was a float-and-sink separation using a solution of calcium chloride as the separating medium. Eagle Seam coal was used for the experiments. The —10 +35 mesh fraction was found to be the most promising feed for producing the low-ash content coal. A batch of 30 tons of — --in. coal was screened at 10 and 35 mesh; the yield of —10 +35 mesh was 20 pct of the feed. This fraction comprised the feed for the separation tests. In spite of the fact that this portion was screened a second time at 35 mesh, the coal still contained 16 pct that was finer than 35 mesh. Three-fourths of the undersize was in the —35 +48 mesh range. A representative portion of the —10 +35 mesh fraction was subjected to batch float-and-sink separations to determine the best gravity to be used in the continuous tests to obtain a high recovery of low-ash content coal. The heavy liquid used was a mixture of carbon tetrachloride and benzene which assured complete wetting of all of the particles. As usual in batch separations, adequate time was allowed for each separation so that even the near gravity particles had ample time to separate. The separations were made at increments of 0.01 sp gr from 1.25 to 1.28 and also at 1.32 and 1.59. Each specific-gravity increment was assayed for ash content. From these data it was concluded that 1.27 sp gr was best for the continuous separation of the coal. The products from the batch separation were composited into float 1.27 and sink 1.27 sp-gr fractions; these were assayed for ash, iron, and silicon. Table I shows the results of the batch separations. The composite float 1.27 fraction contained 66.04 pct of the total weight, and had an analysis of 0.79 pct ash, 0.073 pct iron, and 0.112 pct silicon, or 0.185 pct iron and silicon combined. These data are indicative of the results possible if a perfect separation is made at 1.27 sp gr under static conditions. Inasmuch as the method under investigation is a dynamic system these results could not be obtained. It remained to be determined, however, just how close to the theoretical results the actual continuous separation would be.

Jan 1, 1953

By Adam L. Wesner, A. C. Richardson

This paper describes the development of a continuous float-and-sink process to produce coal low enough in ash content to be suitable for production of electrodes. The cleaned coal had a combined iron and silicon content of 0.239 pct. The efficiency of recovery was 84 pct. DURING World War I1 the demand for electrode carbon was greater than could be met by the supply of petroleum coke available for this use. It was believed that coke made from an extremely low-ash coal might be a suitable substitute for petroleum coke. Requirements for electrode carbon to be used for the production of aluminum are that the silicon plus iron content shall be not more than 0.14 pct of the coke. However, during the period when petroleum coke was in short supply, it appeared that relaxations of the specifications might be allowed to permit 0.4 pct iron plus silicon in the coke. For this work, the specifications were that the coal should contain less than 1 pct of ash, and the combined iron and silicon content of the coal should not exceed 0.28 pct. Heavy-liquid separations made on a number of coals showed that if certain size fractions of some coals Were separated at low specific gravities the resulting float products would meet the required specifications. The objective of this work was to develop a continuous, commercially feasible process for producing low-ash coal. After consideration of various processes, the method chosen was a float-and-sink separation using a solution of calcium chloride as the separating medium. Eagle Seam coal was used for the experiments. The —10 +35 mesh fraction was found to be the most promising feed for producing the low-ash content coal. A batch of 30 tons of — --in. coal was screened at 10 and 35 mesh; the yield of —10 +35 mesh was 20 pct of the feed. This fraction comprised the feed for the separation tests. In spite of the fact that this portion was screened a second time at 35 mesh, the coal still contained 16 pct that was finer than 35 mesh. Three-fourths of the undersize was in the —35 +48 mesh range. A representative portion of the —10 +35 mesh fraction was subjected to batch float-and-sink separations to determine the best gravity to be used in the continuous tests to obtain a high recovery of low-ash content coal. The heavy liquid used was a mixture of carbon tetrachloride and benzene which assured complete wetting of all of the particles. As usual in batch separations, adequate time was allowed for each separation so that even the near gravity particles had ample time to separate. The separations were made at increments of 0.01 sp gr from 1.25 to 1.28 and also at 1.32 and 1.59. Each specific-gravity increment was assayed for ash content. From these data it was concluded that 1.27 sp gr was best for the continuous separation of the coal. The products from the batch separation were composited into float 1.27 and sink 1.27 sp-gr fractions; these were assayed for ash, iron, and silicon. Table I shows the results of the batch separations. The composite float 1.27 fraction contained 66.04 pct of the total weight, and had an analysis of 0.79 pct ash, 0.073 pct iron, and 0.112 pct silicon, or 0.185 pct iron and silicon combined. These data are indicative of the results possible if a perfect separation is made at 1.27 sp gr under static conditions. Inasmuch as the method under investigation is a dynamic system these results could not be obtained. It remained to be determined, however, just how close to the theoretical results the actual continuous separation would be.

Jan 1, 1953

By J. M. Dahl, R. J. Warrick, O. K. Riegger, H. Van Vlack

A liquid which is rich in oxygen (and silicon) develops at steel rolling temperatures in resulfurized and plain-carbon steels. This liquid fluxes solid manganese sulfide. The composition of the liquid and the resulting microstructures vary with the manganese/silicon/oxygen ratios in the steel. The observations and conclusions zuhich are presented are used 1) to suggest a mechanism for MnS deformation in resulfurized steels, and 2) to rationulize hot-shortness anomalies between plain-carbon and resulfurized steels. 1 HIS is a summary of the dependence of sulfide inclusion microstructures upon steel composition, and an interpretation of the behavior of sulfide inclusions at steel-rolling temperatures. Sulfide inclusions are known to have several metallurgical effects upon steel. Their effects upon hot-shortness are best appreciated. Although hot-shortness is well known, it is questionable whether its mechanism is fully understood because there are several anomalies in our interpretation. For example, why should not high sulfur contents produce extensive hot-shortness in free-machining steels ? A second metallurgical consequence of sulfide inclusions appears because sulfide inclusions improve machinability. Furthermore, globular inclu- sions are to be desired over elongated inclusions. To date, we know that lower silicon contents (< 0.010 pct) favor the globular sulfides, but we do not know why this interrelationship between silicon content and inclusion shape exists. Finally, the evidence is strong that the surface quality of a hot-rolled steel is particularly sensitive to the sulfur content. SUMMARY OF PREVIOUS WORK The role of sulfur in hot-shortness was first suggested during the past century. It is uncertain who was the first to conclude that sulfur was less deleterious in the presence of manganese, and that manganese altered the sulfide phase from a liquid FeS to a solid MnS at steel-rolling temperatures. However, Urban and chipman&apos; emphasized that liquid FeS may accumulate as an interdendritic film during solidification. More recently, Keh and Van lack&apos; showed that the intergranular liquid does not completely surround the metal grains at all rolling temperatures. Rather, a small finite dihedral angle exists when geometric equilibration is attained at

Jan 1, 1962