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By L. I. Cothern

The introduction of mechanized mining has created a demand for long working faces. It has also prompted mining men to contest the old theory that longwall methods can be used only where roof conditions are ideal and where pack-wall material is plentiful. "Longwall" as used in this paper means "modified longwall," "semi-longwall," or any of the various ''wall" or "long-face" methods of mining. Many mines are now using long conveyor faces that differ only in their methods of development, types of roof support and method of loading coal onto the conveyor. Some types of longwall operations are being carried on successfully under conditions heretofore considered impossible by men experienced in longwall mining. With possibly one or two exceptions, long-face methods in Alabama are a direct result of the need for lower mining costs. The advantages over room-and-pillar systems were clearly expressed in an article by Messrs. Fies and Lacy of the DeBardeleben Coal Corporation1 as follows: (1) increased tonnage per miner; (2) increased percentage of lump coal; (3) reduction in cost of development; (4) elimination of the cost of room yardage; (5) reduction in the cost of haulage, from ability to use larger cars; (6) reduction in the cost of machine cutting; (7) reduction in cost for tracks; (8) reduction in the cost of deadwork; (9) reduction in the cost of supervision. An attempt on the part of the operator to gain these advantages by changing from room-and-pillar to longwall requires considerable courage, and credit should be given to those men who have done their bit to meet the competition of rival fuels. The initiatory problems to be solved are in reference to: (1) retreating or advancing system, (2) length of wall, (3) method of roof support, (4) method of entry development, (5) type of conveyor or loader, (6) hand vs. machine loading (onto conveyors), (7) hand vs. machine loading in entries, (8) control of roof pressure,

Jan 1, 1940

By Wilbur A. Nelson

In 1839, Gerard Troost,1 the first State Geologist of Tennessee, reported the occurrence of zinc ores in east Tennessee, in connection with the iron ores at Embreeville; in 1844,2 he refers to the zinc deposits of east Tennessee, especially the apparently rich deposits occurring in Jefferson and Claiborne Counties, while his ninth annual report 3 s a description of the zinc deposits of Jefferson County and a description of the most improved processes by which zinc is extracted from its ores. Yet, only during the last few years have these ores been successfully worked. As far as can be learned, prior to the systematic development of the Mascot district in 1911, no large-scale or successful operation of any of the zinc deposits was carried on. But in that year, after several companies had made considerable progress in developing the Mascot area and had proved a relatively extensive body of low-grade sulfide ore, the American Zinc Co. entered the field. It introduced modern methods of prospecting and mining and from the first was successful. Too great credit cannot be given this company for its pioneer work in a previously unimportant field. Throughout the history of its operations, the American Zinc Co. has confined its efforts to underground mining of the sulfide ore, sphalerite. This company has found that successful results in zinc mining in east Tennessee can be achieved only by expending large sums in prospecting and blocking out bodies of pay ore in sufficient magnitude for large-scale operations. At Mascot are located the mines of the American Zinc Co. of Tennessee, the mines being situated along the Southern Railway in the Ilolston River Valley, Knox County, about 13 miles northeast of Knox-ville. At first only open pits, which were worked for oxidized ores, were operated and the production was small. In 1900, the Roseberry Zinc Co. was organized and sank to a depth of 187 ft. what is now known as No. 3 shaft of the American Zinc Co. The upper 30 ft. was in residual clay,

Jan 1, 1925

By G. L. Oldright, F. W. Schroeder

Very great changes were made in the dimensions of the smelting hearths of the furnaces in the period from about 1800 to 1906, the length increasing from about 11 to 116 ft., and the width from 8 to 19 ft. During this time the tonnage smelted increased from about 9 to 250 tons per 24 hr., and the tons of charge smelted per ton of coal increased from 0.77 to 4.3. Dr. Mathewson3 noted no great difference in the "fuel ratio" (i. e., the amount of charge smelted per ton of coal) as the furnace at Anaconda was increased in length by stages from 85 to 116 ft. (The percentage of copper in the slag, however, was lowered from 0.42 to 0.36 per cent. The other components of the slag were not given.) Lump coal fired on grates was the fuel used during this period. The practice in operating the furnaces over such a length of time naturally varied considerably, and there were differences in composition and nature of the charge, yet it may he considered that the improvements made were due largely to increases in the size of the furnace used. Doubtless some credit should be given to improvements in operating technique, like changes in the methods of firing the lump coal. However, the greater part of the advance was probably due to factors influencing the

Jan 1, 1928

By J. E. Pogue, F. G. Coqueron

This paper describes the sources of funds required by the petroleum industry to finance capital expenditures and also presents a discussion of the effect of rising construction costs on these expenditures. The petroleum industry obtains its capital funds from several sources: (I) internal, from retained cash earnings; and (2) external, from borrowings and the sale of securities to the public. The upward trend of capital expenditures of the petroleum industry is caused in the main by the influence of two powerful factors: (I) the physical growth in the demand for oils; and (2) the rising cost of drilling wells and constructing refineries, pipe lines, and other facilities. The segregation of these factors is accomplished by deflating the actual capital expenditures so that they are shown in terms of 1939 costs and then subtracting the adjusted series from the actual figures to yield a set of data representing the expenditures made on account of higher costs. Rising costs affect prices and the portion attributable to this factor had to be generated from the cash earnings of the industry, which called for higher oil prices. Introduction Capital may be defined as "wealth employed in or available for production." All production requires capital. Expanding industries require more capital than static ones, and technological industries employ more capital than. those in which little equipment is needed. The petroleum industry is both rapidly growing and highly technological, and, being a large industry, its capital requirements are prodigious, amounting to about one-seventh of the total of all American business, excluding agriculture.* Capital formation may be defined as the method by which the wealth or capital needed in the productive processes is created. There are various ways in which capital funds may be obtained but there is only one way in which capital can be created—out of production in excess of consumption, that is, savings. The physical realities are simple, but the monetary concepts are complicated because the mechanism of credit can draw upon future savings. Source of Capital Funds An industry, such as the petroleum industry, can obtain its capital funds from

Jan 1, 1949

By R. B. Woodworth

Discussion of the paper of R. B. Woodworth, presented at the New York meeting, February, 1916, and printed in Bulletin No. 107, November, 1915, pp. 2247 to 2312. R. B. WOODWORTH, Pittsburgh, Pa.-This is a very long paper. It is a structural engineer's contribution to the art of mining and is written from his standpoint rather than from that of the mining engineer, and is, therefore, a study in the development of drilling structures by one who has made it his business to design structures rather than mechanism and machinery and rather than to utilize those structures in the actual exploitation of oil and gas. Drilling practice varies widely in different oil and gas fields. The , problems of western Pennsylvania are much simpler than the problems of the Mid-Continent and of the Gulf Coastal Plain and these again are simpler than problems of the Pacific Coast. The history of the commercial development of oil and gas is recorded in the annual publications of the U. S. Geological Survey and other bodies whose business it is to make record of statistics. The mechanical and structural features of the art of drilling have not yet received adequate treatment by the historian. Scattered references may be found on the subject in almost any work dealing at large with petroleum and its production. These references, however, are to those particular aspects of the matter that were contemporary with the publications themselves, but so far as I am aware there is no continuous and comprehensive account written of the development of drilling structures from their beginnings down to the present time, and certainly the more modern application of steel in the construction of such structures has not previously had an adequate discussion. With this latter phase of the subject I have been intimately associated, indeed, taking to myself the credit for having, in a way, been responsible more than any one else in the United States for the application of steel in the manufacture of drilling structures, and the purpose of the paper which is now before you is to record particularly the steps in that development while the subject is still fresh and the data available.

Jan 5, 1916

By E. J. Longyear

The rapid development of the Mesabi range has been a matter of much wonder to those familiar with ore-deposits elsewhere, and much skepticism was shown when " millions of tons of ore on the Mesabi" was first reported. Now, however, with over 8,000,000 tons to its credit at the close of 1896, a prospect of 3,000,000 more this year, and more ore " in sight" than ever before, it is evident that the first claims for the range were not so greatly exaggerated as perhaps even those who made them thought they were at that time. An explanation of the ease with which these deposits have been explored is found in their mode of occurrence. Lying in flat beds and near the surface, and only exceptionally occurring under a taconite " capping," the prospector had only to sink a few vertical test-pits on a fortyacre tract down to the rock to be reasonably sure whether his property contained ore or not. If he found ore in one or more of these preliminary pits, he would then fill in with more pits until the ore-area was entirely outlined by test-pits from 200 to 400 feet apart. In the early days of the range the testing was almost entirely done by digging pits with pick and shovel. When water was encountered, work had to be stopped, unless a steam pumping-plant was put in, resulting in greatly-increased expenses. Latterly, drills have been used with great success in continuing the exploration after water has been struck in the pit, rendering further progress with pick and shovel impracticable. There are several kinds of drills in use. The diamond-drill is largely used, and possesses the advantage of being in readiness to drill rock if thought advisable, the taconite being very hard and almost impossible to drill except by the use of diamonds. Some form of churn-drill has been much used. This may be either a steam- or a horse-power-drill. The principle is the same in each, the cutting being done by percussion instead of by rotation, as in the case of the diamond-drill. A churning motion is given by passing a rope from the top of the

Jan 1, 1898

By A. W. Allen

Progress in the art of amalgamation in recent years has been negligible, partly because a copper plate, though it occupies extensive floor space, requires frequent attention and invites theft, is a simple piece of apparatus that gives visible results; partly because the impression prevails that amalgamation is too primitive a process to merit consideration by an up-to-date metallurgist. Both these objections can be overruled. Plates can and will be superseded by more efficient, theft-proof amalgamating units. Improved methods of application other than by settlement or by impact, neither of which is effective for removal of fine gold, will be developed, and the process given wider opportunity. As A. F. Crosse aptly remarked, neglect to utilize amalgamation when free gold can be recovered thus is comparable to the decision of a storekeeper to deal only with credit customers. Usual practice is to follow amalgamation with cyaniding. Rarely is attention paid to the possibility of reversing the order—of extraction of the fine gold first by cyaniding; the coarse, subsequently, by amalgamation. Such a sequence avoids the alleged hazard that amalgamated gold particles may be unacted upon by cyanide, whereas cyanided gold particles are readily amalgamated. Research has indicated, however, that the mercury coating on a gold particle is easily soluble in cyanide solution, probably because such coating is a compound of gold and mercury. Comparative-test results at one plant, of cyaniding a ground concentrate before and after amalgamation, showed total extractions of about 90 and 100 per cent, respectively, indicating high solubility of the mercury-gold particle, if present, or the advantage of preliminary impoverishment before cyaniding, or both. The contention that a loss in residue from an amalgamation-cyanidation plant is occasioned by presence of amalgamated gold that escapes action by solution is not supported by adequate evidence. The function and scope of mercury as an aid to extraction of gold by cyanide is deserving of attention. It is a powerful desulfurizer. To restrict an extractive process to a concentrated product is logical and economical, if preliminary concentration will segregate a high per-

Jan 1, 1935

By C. E. Shoenfelt

There were 110 important discoveries of either oil or gas in Co1orado in 1935. There was, however, further development of the Price structure in southern Colorado and developments since the first of the year indicate. that an important oil field may be in the making. The discovery of oil in Price structure was made by the Oil City Petroleum Co. late ill Novem-ber, 1934, in its No. 2 Garnett in the northeast corner of lot 3 in the SW.¼ of sec. 25-33N.-2E. This well developed a good showing of oil in Dakota sand at 970 ft. The hole filled up 15 ft. with 40° gravity oil overnight and after standing for several days the oil level was 400 ft. higher. As a result of the discovery of oil by the No. 2 Garnett, three wells were drilled by the William E. Hughes Estate. Two of these wells had good showings of oil and may make good producers but it is doubtful whether they will produce the estimated capacity of 500 bbl. each with which they have been credited. Although the Hughes Estate wells have been completed for some time, they have not been given thorough production tests because of the isolated position of the field and lack of proper facilities. The. first well drilled by the Hughes Estate was located on the west side of the Navajo River on the downthrow side of a fault. It encoun-tered water ill the Dakota sand at 1285 ft, and was abandoned in green shales of the Morrison at 1405 ft. Well cuttings from the Dakota sand showed some evidence of once containing oil, so a 1ocation was selected for No. 2 Fee on the east side of the river and on the upthrow side of the fault. Oil was discovered in Dakota sands ill 1935 by Continental Oil Co. in its No. 3 Hoye, NW.NW.NE. of sec. 34-9N.-78W., on the South McCallum anticline in North Park, Jackson County, Colo., but on account of heavy flows of carbon dioxide gas under high pressure it has been impossible for the company to get an accurate gage of the oil production. The freezing action of expanding carbon dioxide makes the producing of the oil difficult and costly.

Jan 1, 1936

The following have been compiled from information furnished through the courtesy of Dr. W. P. Haynes, of London, and Mr. T. V. Grigorescu of Ploesti, Rumania. Gura Ocnitzei was the most active field during the year, furnishing 40 per cent of the production and 50 per cent of the drilling activity. Extensions to the west in this field were made both by Concordia and Romana Americana. In these new extensions the bulk of the production comes from the Drader member of the Dacian, with an average depth of 1300 m.; the underlying third Meotic at 1700 m. has not been developed yet. In Gura Ocnitzei east no new drilling has been done in 1933, but here declining pressures have led to the extensive use of gas-lift and pumps. Ochiuri saw some small drilling activity, but production declined. Two good wells were brought in by Unirea and Astra at the close of the year. Boldesti continued to be developed on a general plan by the four major companies interested. Production was from the Meotic, which in this dome has been penetrated for 356 m. Reserves have been estimated at about 63,000,000 bbl. An important discovery in this area was the bringing in of Credit Minier No. 1 Harsa to the east of the main field and producing from the Meotic. This well came in during October, 1932, and is now making 1400 barrels. In the Moreni Piscuri field only routine operations have been carried on. The prolific sands are now declining rapidly. Ceptura also saw only routine operations. In the Arcesti field development of the Meotic continues. Seven new wells were brought in during the year and ten were drilling at the close of 1930. The field produced over a million barrels for the first time during 1933. In the other fields only routine operations were carried on. A considerable increase in efficiency of operations was noted during the year. The average drilling time has been reduced, coring programs have been amplified, and much care has been taken in straight hole drilling. The Schlumberger electrical coring apparatus is extensively used. Electric-driven rotaries have been introduced at Gura Ocnitzei. The Moniteur du Pétrole Rouman reports that the index cost of drilling one meter, taking 1929 as a base of 100, has been reduced to 32 in 1933.

Jan 1, 1934

By C. E. Shoenfelt

There were 110 important discoveries of either oil or gas in Co1orado in 1935. There was, however, further development of the Price structure in southern Colorado and developments since the first of the year indicate. that an important oil field may be in the making. The discovery of oil in Price structure was made by the Oil City Petroleum Co. late ill Novem-ber, 1934, in its No. 2 Garnett in the northeast corner of lot 3 in the SW.¼ of sec. 25-33N.-2E. This well developed a good showing of oil in Dakota sand at 970 ft. The hole filled up 15 ft. with 40° gravity oil overnight and after standing for several days the oil level was 400 ft. higher. As a result of the discovery of oil by the No. 2 Garnett, three wells were drilled by the William E. Hughes Estate. Two of these wells had good showings of oil and may make good producers but it is doubtful whether they will produce the estimated capacity of 500 bbl. each with which they have been credited. Although the Hughes Estate wells have been completed for some time, they have not been given thorough production tests because of the isolated position of the field and lack of proper facilities. The. first well drilled by the Hughes Estate was located on the west side of the Navajo River on the downthrow side of a fault. It encoun-tered water ill the Dakota sand at 1285 ft, and was abandoned in green shales of the Morrison at 1405 ft. Well cuttings from the Dakota sand showed some evidence of once containing oil, so a 1ocation was selected for No. 2 Fee on the east side of the river and on the upthrow side of the fault. Oil was discovered in Dakota sands ill 1935 by Continental Oil Co. in its No. 3 Hoye, NW.NW.NE. of sec. 34-9N.-78W., on the South McCallum anticline in North Park, Jackson County, Colo., but on account of heavy flows of carbon dioxide gas under high pressure it has been impossible for the company to get an accurate gage of the oil production. The freezing action of expanding carbon dioxide makes the producing of the oil difficult and costly.

Jan 1, 1936

By Jeffery L. Kohler, Eric R. Bauer

Prolonged exposure to noise over a period of years generally causes permanent damage to the auditory nerve and/or its sensory components. This irreversible damage, known as noise-induced hearing loss (NIHL), is the most common occupational disease in the United States today. Workers suffering from NIHL have difficulty understanding human speech and hearing other workplace cues. Despite the use of regulations and efforts by government and industry to reduce NIHL, the problem today is as prevalent as it was more - than two decades ago. Recently, the Mine Safety and Health Administration (MSHA) promulgated a new regulation that is designed to reduce NIHL in the mining industry. One of the more significant provisions is the elimination of MSHA's past practice of giving "credit" for the use of personal hearing protection, thereby reestablishing the primacy of engineering and administrative controls. However, there is a knowledge gap that is impeding the development and implementation of engineering and administrative controls. Although significant data exist on the exposure to noise by occupational code, little is known about the noise sources that contribute the most to the worker's dose. This is problematic in a workplace with multiple noise sources and workers who travel among noise sources. Yet without this knowledge, it is difficult to focus control efforts in any practical manner. Thus, it is important to characterize noise sources sufficiently well so that the sources most hazardous to hearing are identified and those conditions of exposure that are most amenable to engineering controls are pinpointed as well. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) is conducting a cross-sectional survey of noise sources and worker noise exposures in the mining industry to address this deficiency. The initial effort, conducted at a coal preparation plant and results are described in this paper. Preliminary analyses indicate that the noise levels on all floors exceeds 90 dBA in most areas, and that levels as high as 115 dBA were recorded. In addition, the one worker whose responsibility is to monitor the equipment and "house clean" the plant is slightly overexposed, even though he spends only half the shift in the plant. General information on the hearing loss problem in mining, a review of hearing protection use and noise regulations in mining, and other background materials are also presented.

Discussion o f Papers. Meetings of the Institute offer opportunity for social acquaintance and exchange of ideas, for the--presentation of papers, and-for discussions. thereon ; also incidentally for viewing under especially favorable conditions mining operations and industrial establishments, and for hospitalities which demonstrate the brotherhood clue to kindred interests. Placing sociability prominent is not to be assumed as relegating other features of meetings to subordinate positions; but during about 40 years of membership in the Institute, the value of acquaintances formed (often ripening into close friendship), and the interchange of data, have frequently demonstrated that the social feature of meetings is of great and lasting value to the membership. Of a roll embracing 4,011 members, resident in all parts of our country, and scattered in various portions of the world, only a small fraction are able to attend meetings, even if the localities selected are alternately widely separated. Hence, the return which most members receive for their annual assessment of dues is limited to the publications issued, and the credit of being recognized as a. member of a great and worthy organization. The greater the value of the contents of our publication, the fuller the return which goes to members. While the Institute disavows responsibility for views or statements made ill papers which appear in its Transactions, the fact that these contributions, after passing proper censorship, are accepted by the Institute and spread before the world may properly be received by the writers as endorsements of their (the writers') ability to present a specific technical or industrial proposition worthy of being carefully read. But the mere presentation and publication of contributed papers falls short of fulfilling one important feature of our meetings. If the purpose is confined to having the writers' views, discoveries, theories, or methods published, this can be obtained through the technical or trade journals and magazines. The true value of a paper presented at a meeting of the Institute may often be gauged by the discussion which it encourages, although there are contributions of decided value which do not especially invite discussion. However, most Of the papers offered contain statements apt to encourage criticism or elaboration by others whose experience or knowledge, or both, assist in combating or endorsing statements made.

Jan 7, 1913

By M. L. Requa

This paper is abstracted from the report of the Appraisement Committee of the Independent Oil Producers' Agency, of which the writer was Chairman. The other members of the committee were M. V. McQuigg and R. S. Haseltine. To Thomas Cox, engineer in charge of the investigation, and to his efficient staff of assistants, is due the credit for the detail work necessary in carrying out the plan of the Committee. It treats only of the valuation of the lands, wells, and piping, without going into details of equipment and other features. It was recognized, early in the operation, that the value of oil lands was the value of oil to be extracted, and marketed, less the costs attendant thereon. Referring this back to the costs in cents per barrel, it became obvious that surface improvements, absolutely necessary in the production of oil, from wells then drilled; had no separate and independent value aside from the value of the land, but that any excess equipment, not necessary for the production of oil from present wells, such as drilling tools, well casing, etc., should be given a present condition value. In valuing the properties of the Independent Oil Producers' Agency, the Committee has considered the following facts: 1. That from each property there will ultimately be. produced a certain total quantity of oil. 2. That in the production of that oil a certain total quantity of money will be expended. 3. That a certain total amount of money will be received from the oil. 4. That the total net receipts will be the total gross receipts less the cost of development and production. 5. That the present value of the net receipts must be such an amount that when invested by a purchaser it will be returned with 8 per cent. interest additional during the life of the property.

Jan 2, 1918

By Cyril Jones

13.9-1. Introduction. Any mining venture or project is undertaken with a view of gaining some benefits, which, with the modern limited corporation, means earning a return to the stockholders for the use of their funds. Thus, any manager, when confronted by an opportunity of expending funds, must realize that the funds should generate a satisfactory return. The problem then becomes one of how the manager should best expend, if he should expend, funds for opportunities that become available to him. In the evaluation of a mineral property, or of a project within an operating mineral property, there must be cognizance of the fact that the final return is dependent on many factors that are not present in other industries. The primary factor in mining operations is the orebody, which has a diminishing life. This diminishing life gives the decision maker a range of choices; for by expending more capital for a larger plant, he can work the deposit out in a shorter period (16). This may, in fact, maximize the return on the investment. Alternatively, he may wish to maximize the total profits, a course which usually requires a lower capital investment and allows a longer working life for the deposit before final depletion. Other factors that have great importance in the evaluation of mining projects are the taxation treatment of mining profits from the viewpoint of depletion, depreciation, and investment credit. Investment opportunities involve expending funds at the present time in return for future benefits. These future benefits have a degree of risk in that the annual amounts of benefits and their duration cannot be fore- cast accurately. The treatment of risk in economic analysis involves the quantification of the degree of variability of the expected future benefits and also of the initial capital expenditure. This treatment in mineral exploration may be extended to cover the initial search for an orebody

Jan 1, 1968

By Maria G. Alves, Alexandre M. Stumbo, Francisca M. A. Pinheiro, Jonas Alexandre, Sergio N. Monteiro, Valdo da S. Marques, Paulo R. N. da Silva

"Brazil is among the few countries with potential for developing all sources of renewable forms of energy. In particular, the country is leading the world efforts of substituting petroleum based fuels for biofuels, such as ethanol and biodiesel. Most of the Brazilian petroleum, which has now achieved self sufficiency, is extracted from offshore wells located at the north region of the state of Rio de Janeiro. In view of the future depletion of petroleum, the State University of the Northern Rio de Janeiro (UENF) has created a Center for Alternative Energies (NEAL) to carry out R&D programs on renewable forms of energy. Today, the main project of the NEAL/UENF is a model park for generation of renewable forms of energy. The objective of this work is to present the structural concept of the park and discuss its contribution in terms of scientific, technological, economical and environmental benefitsIntroductionEnergy is presently a key issue in the world agenda for sustained development and environmental protection. It is of common agreement that the existing status of increasing use of fossil fuels, mainly petroleum, natural gas and coal will not only cause depletion of these resources with a consequent elevation in price but also climate changes, especially global warming. In fact, the humankind may be already facing an irreversible situation of climate alterations as well as reduction of conventional sources of energy. The worse predictions foreseen by specialists, still for this coming century, are dramatic disasters due to catastrophic weather in association with a profound energetic crisis. This scenario may, however, be avoided by actions that could effectively tackle the core of the problem. These actions have been suggested and discussed by scientists and leading authorities, especially in international symposia [1-3]. In particular, the Kyoto Protocol proposed goals for reduction of greenhouse gas emissions as well as a mechanism of carbon credits to allow for decreasing CO2 content in the atmosphere without affecting industrial production [3]."

Jan 1, 2008

[A discussion suggested by the paper of Mr. James Gsyley on " The Development of American Blast-Furnaces," read at the New York meeting of the Iron and Steel Institute, October, 1890, and reprinted from the Journal of that Society in Bans. A. I. M. E., xix., 932.1 (Cleveland Meeting, June, 1891.) [Kote by the SecretaRy.—The three following contributions to this discussion were communicated by letter to the Secretary of the Iron and Steel Institute, and were received by me too late for insertion in vol. xix. of the Transactions.] FRed. W. Gordon, Philadelphia, Pa.: Mr. Gayley's paper calls our attention to the very expensive blunder hitherto made in blowing too much wind in a given size of furnace. It was quite evident from an analysis of blast-furnace operations that the work we are doing in America is anything but creditable. We were consuming fully 1000 pounds of coke more than is necessary for each ton of iron made, and were hammering the linings of our furnaces out in a very short time, and nothing but the very high price of pig-iron would stand the drain. It had long been my pet scheme to gradually reduce the quantity of air, at the same time increasing the burden to the maximum and decreasing the limestone, and determining, if possible, the fuel economy which might be reached consistently with the maximum production of the furnace. After the success of the Isabella furnace at Pittsburgh, which was remodelled in 1880, the North Chicago Rolling Mill Company had

Jan 1, 1892

By Robert Warner

The growing importance of screening makes an accurate measure of the quality of a sizing operation desirable. Screen efficiency is considered equal to the percentage of true undersize in the feed obtained as undersize from the screen. This method is unreliable, as it gives the same credit for removing minus 200-mesh material as for removing material just able to pass the aperature of the screen. A more accurate measure of screen efficiency is to consider only the work done on the "difficult" grains, that is, those grains of which the intermediate diameters closely approach the screen aperture.. The application of this method is given, together with the derivation of formulas and an example of their use. Is AN accurate measurement of the efficiency of a screen under a given set of operating conditions valuable? If so, what is the efficiency; of, a screen and how can it be measured? Sizing, especially of the finer sizes of material, has increased in importance in the development of flow sheets as a result of the perfecting of the rapid vibrating screens. More consideration should be given screens in the preparation of ball-mill feed, where they permit the admission of a dryer feed than, the classifier. Where possible, the introduction of a screen ahead of the primary ball-mill, and the diverting of ore below, say, 4 mm. to a secondary mill, might result in a greater overall economy because of the thicker feed and the better, adjustment of crushing media and mill operation to the reduction demanded. With the present trend back toward a combination of gravity methods and flotation, rather than flotation alone, the accurate, economical sizing possible with the new screens makes fine jigging a method to be considered. W. 0. Borcherdt1 and John Bland2 discuss the screening problem and also the value of close sizing in the concentration of some of the rare-metal ores. If a screen is to be used, it should be selected in competition with others; other things being equal, that screen which makes the cleanest oversize should be preferred. The quality of the screening and the tons

Jan 1, 1924

By C. P. Broadbent

Due to growing .public awareness of environmental issues and greater sensitivity towards waste management, many countries around the world are implementing more stringent legislation governing the storage and disposal of hazardous wastes containing heavy metals such as As, Sb, Pb, Cd or Hg. These wastes can no longer be dumped without providing clear guarantees that the material concerned is environmentally safe and will not leach toxic elements to the surroundings. In the Netherlands the current dumping charge for chemical waste (i.e. worst category) is $280/t, and for industrial waste this cost reduces to $75/t. If the material can be reused there may be a small positive credit for selling it, for example discard slag as an aggregate to the construction industry. A number of (pyre)-metallurgical operations, mostly associated with the extraction of metals from sulphidic ores, produce arsenic residues in the form of As2O3 containing flue dusts and speises. If the flue dust is of high purity it can be sold, though many traditional uses are being substituted by other materials. In many cases upgrading the quality of the arsenical dusts is not possible for either technical or economic reasons. Traditional practice is to dissolve these dusts in acid prior to precipitation as ferric arsenate, which is at present classified by many countries as industrial waste and can be dumped. Recent work, however, has cast doubt on the stability of arsenates for disposal and alternative disposal routes have been investigated. Tests have shown that up to 10% (dm) As can be incorporated into "glassy" silicate slags with very low levels of arsenic leaching in the cooled product. Calcium arsenate was added to a range of synthetic and industrial slags from the system SiO2-FexOy-CaO-A12O3-AsmOn, under mildly oxidising conditions and quenched subsequently in water. It would appear that this represents an environmentally acceptable method for the disposal of many arsenical residues and there is some optimism that this method will be equally applicable to the disposal of other toxic metal residues.

Jan 1, 1994

By James E. Lawver

Efficiency of industrial research and development depends on the ability of engineers and scientists to collect and present data to top management for decisions. In many cases, the data presented are so deceptive that management makes costly wrong decisions. Since management personnel often are selected on the basis of higher administrative quality than technical ability, it is the responsibility of the industrial scientist or research engineer to make certain that the data presented tell a completely ac- curate story of each industrial problem. It is rare that misleading data are deliberately presented, but when this is done, it is? of course, dishonest. The rise of deceptive data usually stems from the lack of knowledge of experimental design and statistical methods of analysis. Most of the better chemical engineering schools have recognized the need for courses in industrial experimentation and many of them offer complete courses at both graduate and un- dergrarluate levels. By contrast, many of the mining and metallurgical schools have not recognized the importance of industrial experimentation courses and some of them, in fact, do not allow credit toward a mining or metallurgical engineering degree for statistical courses even when taken as an elective. The sole purpose of this paper is to make a plea for mining and metallurgical schools to present required industrial. statistical courses for their graduates. It is true that fine industrial research has been accomplished in the past without the assistance of any statistical techniques. Industrial problems have also been solved without the use of digital or analog computers, electron microscopes or other modern conveniences. The fact remains, however, that the correct use of these modern tools tends to reduce the cost of research and to eliminate costly errors. A working knowledge of experimental design and statistical data analysis must simply be viewed as a valuable tool whose proper use will greatly reduce the cost of experimentation and minimize the cost of false conclusions. These statistical methods, however, simply cannot replace fundamental knowledge or, for that matter, "good horse sense". Nevertheless. an experimenter armed with fundamental knowledge and good horse sense but completely ignorant of elementary statistical techniques, may easily present his data in such a deceptive form to cause management to make incorrect decisions.

Jan 6, 1962

By Walter Barnum

AS a member of the Institute and as the president of the National Coal Association, I come before you today in a dual role. As an Institute mem-ber I welcome the opportunity to make complimentary reference to the growing support which bituminous coal operators are giving to programs looking to the advancement of the engineering profession, and to suggest plans whereby these programs may be enlarged to mutual advantage. As a representative of the bitu-minous industry, it gives me special pleasure to express the appreciation of the industry for the services ren-dered to it by members of your profession. Needless to say, there is a close relationship between the engineer and the coal operator. With increasing frequency and in the interests of the industry, the engineer is becoming more of a factor in the business of producing coal. I need look no further for an out-standing example of this encouraging trend than to Samuel A. Taylor, who not only is a bituminous coal producer but also has risen to such eminence in the engineering profession as to have been chosen the head of this great body of technical men, the American Institute of Mining and Metallurgical Engineers. There are many coal operators whom I might mention as having achieved distinction in the engineering world, such as Howard. N. Eavenson, chairman of the .Coal and Coke Committee. And I would be guilty of a serious .oversight if I failed to make reference to Eckley B. Coxe, one of the founders of the Institute in 1871, a prominent anthracite operator and credited with several important inventions. While it is true that a. considerable number of execu-tives of coal-producing companies in this country came up through the engineering ranks. the proportion of mine executives in England, France, and Germany who are graduate engineers is much larger than it is in the United States. In France all members of the staff are engineers and such is the case in Germany up to the owner of the mine. In Germany the owner is not so frequently an engineer as is the rule in France.

Jan 3, 1927