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By Thomas H. Sheldon

In the zeal for opening up new ore-bodies, or for extracting the ore from attractive bodies already opened up, we very often lose sight of the fact, that, after all, the operation of a mine is a business proposition, pure and simple, and, for the best working-results, should be treated upon a strict business basis. Of course, in every mine of consequence, a record is kept of expenditures and receipts, and such glittering generalities as " gross receipts," " net receipts," " mining expenses," and a per cent. profit," can be told to the cent; but does this record show economy of management, as compared either with the same record of other months, or with the record of other mines of the same class ? Moreover, if such a record shows that the cost of mining is high, does it in any way enable the manager to put his finger on the leakage ? Does it necessarily follow that a mine which makes a profit of, say, 40 per cent. on 25-dollar ore, is doing less economical mining than one which saves 60 per cent. on 80-dollar ore ? Of course the figures in the latter case look the more attractive; yet when it comes to the point of saving everything which can be saved, and of cutting down expenses to the lowest possible cost of operation, the former mine is doubtless on the firmer and more economical financial basis. But as to the relative merits of the system of mining in the two cases, nothing could be decided without a basis of detailed comparison ; if one system is more economical than the other, why is it so, and wherein does the advantage lie ? This can be shown only by keeping accurately the cost of each mining operation. And no matter how dissimilar two mines may be in character and operation, yet there are a few general heads common to all mining operations. In the first place, it is necessary to break the ore from the solid ground;

Jan 1, 1907

By G. Caetani, E. Burt

Jan 1, 1907

By William H. Shockley

[Secretary's Note.—The following notes, arranged and edited in this office, but not yet revised by the author, were placed at my disposal with much modest hesitation (due to their incomplete and fragmentary character), upon my earnest request, and my argument that such recent and trustworthy data concerning a new and important mining industry ought not to be withheld from our Transactions, simply because they are not sufficient to constitute a complete academic treatise on the subject. This argument is recommended to the attention of many other members, who are waiting for the opportunity to contribute something "monumental" to our Transaclions. In a number of instances, death has nullified this ambition, and the intended "monumental " contribution has turned out to be an obituary notice by the Secretary, instead of a valuable record of the professional experieuce thus hopelessly lost to the world.—R. W. H.] The official publications of the Russian Government give fairly complete statistics of the dredges operated in the Empire; and in a recent English bluebook, Mr. Cook's report on Siberian Trade presents a brief account of dredging in Siberia. The data in Table I. (not given by Mr. Cook) have been taken from the Gold Mining Messenger (Russian) for July, 1905. These interesting statistics, though incomplete, show that the Yenisei dredges are working on poor ground and yield small returns. According to report, but few yield a profit exceeding 10 per cent. per annum on the capital invested. In the summers of 1904 and 1905, I traveled in the Urals as far north as lat. 61° N., long. 61" E., on the Losva river, a part of the vast system of the Ob river. This clear-water stream starts from the summits of the Urals at an altitude of 4,000 ft., and flows through a flat country, densely wooded with larch, spruce, pine, fir, birch and poplar. The river is full offish, and is navigable for good-sized steamers as far as Ivdell. Winter lasts from early November to late April, the temperature ranging from -60" F. to a summer maximum of 90° F. The rainfall is 20 in. The climate is healthy, although mosquitoes,

Jan 1, 1907

By W. A. Hooker

This portion of Mexico is quite beyond the ordinary routes .of travel, and is seldom visited. Its mines have not the record of enormous wealth which has recently attracted foreign capital to other parts of the republic; but for many centuries it has been a mining country, and at some periods evidently a productive one. In 1881 the writer visited the State and spent some time in the inspection of the mines. The absence of published information regarding its mining industry is his apology for presenting to the Institute these notes on the subject. Oaxaca is, with one exception (Chiapas), the most southerly of the Mexican States. It extends from latitude 18o 20' to 15' 45' N.— about 180 miles, by some 300 miles, in an east and west direction, and embraces a large part of the Isthmus of Tehuantepec. The coast-line is wholly on the Pacific. The State has an area of 27,470 square miles, nearly that of the State of Maine, and a population estimated at one million, or thirty-six to the square mile. The great continental Cordillera which farther north and west expands into broad table-lands, is here converged into narrower limits and occupies the greater portion of the country; the main

Jan 1, 1887

By Charles E. Wait

The old laboratory at the School of Mines was among the notoriously bad ones, being situated in apartments of the main collegebuildings not originally intended, and conspicuously unfit, for the use to which they were put; while, as in many of our schools and colleges, the assaying was done in the basement of the college. Prominent among the disadvantages of such an arrangement are insufficient light, poor ventilation, and little or no provision to carry off offensive gases. It is not my intention now to present a complete description of this building. I wish merely to call attention to a few points in its construction and equipment, which may prove of interest to those who contemplate erecting buildings for snch work, and who may be, as we were in this instance, limited as to funds. In this laboratory every room is well lighted; all rooms used by students are well ventilated, and are provided with closed hoods for

Jan 1, 1887

By H. M. Chance

Jan 1, 1887

By H. M. Howe

The tenacity with which a bad name adheres to a process is well illustrated by the prevalent belief in the irregularity of the product of the Bessemer converter. We have been lately told by an eloquent member that lack of uniformity is the name of Bessemer steel, and that uniform soft steel can only be made in the Clapp-Griffiths Bessemer converter. Yet I believe that, however irregular the percentage of carbon in Bessemer steel may have been formerly, to-day it is well-nigh completely under control. Indeed, the results of a large number of analyses that I' have studied go to show that the

Jan 1, 1887

By Arthur F. Wendt

The earliest knowledge of copper-ores in the Southwest was derived from the Mexicans, who, in the latter part of the last century, discovered and worked the Santa Rita copper mines, now situated

Jan 1, 1887

By Alfred E. Hunt

The application of the color-method for the estimation of manganese in iron and steel, based upon the depth of the characteristic purple color of permanganic acid, was first made in this country, the writer thinks, by one of the members of the American Institute of Mining Engineers, Mr. Samuel Peters, in 1874, at the laboratory of the Bay State Iron Company, and was published by him in the Chemical News. The method is credited to him in the new edition of Crooke's Select Methods. The principle of oxidizing manganese with peroxide of lead, or other oxidizing agents, and determining the amount of manganese from the color of the purple permanganic

Jan 1, 1887

By Charles P. Berkey, John B. Hastings

The reconnaissance of the Goldfield mining-district, describecl in this paper, was made in May and June, 1905, and, though this time was too short for a complete report, the work accomplished may serve as a basis for more thorough future research. Dr. Berkey has examined the rocks collected by me, and I am using his classifications. As a result of further field-work, and Dr. Berkey's examination of the rocks, this paper is an elaboration and correction of my views expressed in the Gold-$elm Sun, May 12, 1905. The sketch-map, Fig. 1, illustrates the geology of the Goldfield mining-district. Goldfield is an eruptive complex, consisting of alaskite (hinary granite), hornblende-andesite, hornblende-dacite, rhyolite, pyroxene-andesite, pyroxene-dacite (sometimes containing a small quantity of olivine), quartz-felsite, olivine-pyroxene-ande-site, and basalt. Considering this list to be arranged in the order of eruption, the age-sequence of the rocks conforms to Richthofen's law, formulated in 1868. From his observations in Europe and America, propylite, andesite, trachyte, rhyolite and basalt, occurring together, succeed one another. In a general way, the medium and the more acidic rocks precede the most basic—a result supposed by some to hare arisen from their position beneath the. surface, and due to a rude stratification by gravity in the original cooling magma during the older history of the earth, or to the same differentiation occurring during a quiescent (molten ?) period preceding eruption, being aided by the ease with which acidic rocks, mixed with water vapors, become fusible. In effect, the more basic and less re-

Jan 1, 1907

By Thomas Leonard Watson

In a paper read by title at the Washingtoil meeting of the Institute,' May, 1905,I discussed at considerable length the geological relations, mode of occurrence, and the genesis of the lead- and zinc-ores of the VirginisTennessee region. The present paper treats of the purely ecorlomic phases of the zinc-ores of the district,—such as methods of mining the ores, their preparation and treatment. The Albemarle coullty mines and plant were discussed in the paper referred to above, and mill not be considered here. Methods of Mining. Until very recently the mining of lead- and zinc-ores in Virginia mas limited wholly to the surface-belt of weathering. The mode of occurrence and the character of the ores to be mined were such as to demand the employment of niethods used in mining secondary concentrated ores. Accordingly, a system similar to that practiced in mining brown iron-ores was employed, being modified to meet the changed conditions. Oxidized or Soft Ores.—Up to the present time practically all the ore mined in the Virginia district has been of the oxidized or soft type;—the silicate, calamine, and the carbonate, smith-sonite; largely the former, which has been localized and concentrated at only slight depths below the surface. Because of the extreme irregularity with which the limestone weathers when stripped of the overlying residual clay, it presents a roughened surface of large and small irregular " chimneys"

Jan 1, 1907

By Frederick T. Williams

The purpose of this paper is to discuss the relative merits of the large 31/8-in. machine and the small 2 1/4-in. tappet machine in driving development-headings; and although the data here presented were obtained from cross-cut headings alone, experience has shown that the results are equally true in drifting, raising and winzing. Recently we drove two parallel cross-cuts through the same formation, using a 3 1/8-in. machine at the breast of one crosscut, and a 2 1/4-in. machine of the same make at the breast of the other. The results of this work afforded an ideal comparison, since in both cases the headings were advanced through rock practically of the same hardness and breaking-properties, the amount of sludging was equal, and there was no difference in the condition of the steel or the machines, the air-pressure or the experience of the operating crews. Some operators in the Cripple Creek district contend that there is ground which cannot be handled with the small machine, the holes being too small to contain enough powder to "pull " the ground, etc. The results obtained in working the property of the Portland Gold Mining Co., however, show that the ground worked by them does not fall in this class. During a period of two years there have been driven, with the small machine, 4 miles and 308 ft. of development-headings, through a diversity of ground, including Pike's Peak granite (a coarsely porphyritic type of granite), highly indurated andesitic or pho-nolytic breccia, true massive andesite, trachytic phonolyte, tuffs, and along dikes of decomposed basalt and hard phonolyte. In every instance a satisfactory record was made. The headings here describe? mere driven through highly indurated andesitic breccia, having a hardness of from 5.2 to 7.2 and a sp. gr. of from 2.2 to 2.8. The action of the breccia under the drill was not materially different from that of ordi-

Jan 1, 1907

By H. T. Morris

ONE of the chief concerns of the Bethlehem Steel Co. naturally is the proper functioning of its organization. This involves the training of a continuous supply of younger men to fill the vacancies caused not only by the inevitable departure of older men, but also by the growth of existing establishment, and by expansion in new directions. It does not oper-ate a student training course with a fixed time schedule or with definite periods of rotation through the differ-ent divisions. To state the case positively, the gradu-ate's training course must operate continuously from the beginning of his employment through a long term of years. No period of weeks or months nor pair of years suffice to bring him into contact with all the com-binations needed to qualify him for the larger destiny toward which we hope he is headed. Our first step in selecting a college man is to require that he have a degree. We thus approximate the assur-ance that at least four annual siftings have reduced the chance that a non-worker may find himself in a job where work is necessary. The next step is to try to ascertain facts, from the graduate and from others who have known him at his home and in 'his college, to indi-cate whether our opportunities offer him a career that will challenge his continuing interest, and hold him to tenacious effort against all happenings. We aim to avoid knowingly bringing into our organization a man who will not develop in it enough enthusiasm to keep him happily striving. Having made our selections, we assemble the gradu-ates into a probationary observation circuit. We-put ourselves under their observation by taking them in small groups, usually of two to four men, on a circuit of every part of the Bethlehem plant, in which every manufacturing principle of our steel business is ex-emplified. The probationers work at something from day to day, with their hands if it can be arranged; otherwise in questioning, examining, and note-taking. Their observations include talks with superintendents, foremen, and workmen, the conditions under which workmen labor, apparatus, machinery, methods, design and operation of plant.

Jan 7, 1928

By F. G. Miller, E. B. Wilson

In 1972, coal mine productivity was in steady decline and labor and maintenance costs were spiralling upward. Yet, despite this sad state of affairs, nowhere in the US at that time was there a comprehensive and coordinated coal research and development plan in the offing. The Bureau of Mines had not yet been charged with such a responsibility, and industry was content to rely on machinery manufacturers for innovations. It was during this period that Bethlehem Steel Corp. determined that a new approach to coal mining research was needed for the industry as well as for the company itself. After studying Bethlehem's own mining practices, the state-of-the-art of mining research elsewhere, and development work by manufacturers, a comprehensive research package was presented to company management in late 1972. The ideas and experience of many operating and management personnel in the company contributed to the formulation of the final plan as approved.

Jan 10, 1976

By F. G. Miller

In mid-1972 we determined that a fresh approach to coal mining research was needed for the industry as well as for Bethlehem. The reasons to us were obvious: Productivity was in the throes of a steady decline, and labor and maintenance costs were spiraling upward. Yet, despite this predicament, nowhere in the U.S. at that time was there a comprehensive and coordinated research and development plan in the offing. The Bureau of Mines had not yet been charged with such a responsibility, and industry was content to rely on machinery manufacturers for innovations. After studying our own mining practices, the state-of-the-art of mining research elsewhere, and development work by manufacturers, we presented a comprehensive research package to our management at the end of 1972. The ideas and experience of many operating and management personnel in our Corporation contributed to the formulation of the final plan as approved.

Jan 1, 1976

By William Benzon

Bethlehem Steel's Cambria Division coal cleaning and preparation plant, operated by Bethlehem Mines Corp., is located in Cambria County, Pa., about 2 ½ miles southeast of Ebensburg. Here, above ground, is the most modern coal preparation plant in the world. Below the surface is a new coal mine also referred to as "the most modern that could be built today." The preparation plant has a capacity of 1370 tons of clean coal per hr. It serves three Bethlehem mines, Heisley No. 31, Revloc No. 32, and the new Cambria Slope No. 33.

Jan 12, 1965

By LeRoy Kienitz

There may be someone here who is not required to run his equipment at its maximum capacity. There may be some fortunate enough to have more crushers than needed, wider conveyor belts than required, and other mill equipment equally oversize. If so, then this paper will have no interest for him; but if most of you are in the situation we in the aggregate producing industry are in, then you probably wish to crowd your mill equipment to its limit. When you do this you must watch for block-up and overloads of all sorts. You need more eyes than you have to guard the critical points. The human eyes that now do nothing much, but watch should be freed for more productive work.

Jan 1, 1961

By Graham Walker

A new Code of Practice for the brake performance of off -highway vehicles was established in Alberta in 1976. Vehicles loaded to gross vehicle weight must be capable of stopping with mechanical brakes five times in quick succession on a grade of 10 per cent from a speed of 28 miles per hour. Comparative trials of various brake systems have been carried out and some combinations capable of meeting the Code are identified. Some problem areas in truck braking are reviewed and potential developments indicated.

Jan 1, 1977

By James Thompson

Mine planning at Consolidation Coal Company's (Consol) Glenharold Mine in North Dakota is being constrained by environ¬mental concerns that did not exist when the mine opened in 1965. One such concern which developed in the mid-1970's is the impact of mining on woodlands that are considered impor¬tant wildlife habitat. To better coordinate mine planning with permitting, a cooperative task force was created to evaluate woodlands for their wild¬life habitat potential. The task force included representatives from Consol and state and federal agencies. This cooperative process is seen as a method of communication between industry and government and as a way of developing decision-making tools for mine planners and regulatory agencies.

Jan 1, 1981

By N. Staroselsky

"Significant energy savings are often possible for centrifugal compressors operating in parallel by improved control strategy and improved instrumentation. Blow-off can usually be reduced by improved surge control combined with a better control strategy for loading and unloading the group of machines. More precise and stable pressure control then becomes possible. This improved control strategy will also decrease the frequency of operation near the dangerous limits of surge or overload or overspeed. A sample station of mixed centrifugal and reciprocating compressors is examined and a substantial energy saving with the recommended control strategy is projected from operating data. Present Operating Conditions of the Compressed Air StationThe Compressor StationThe compressor station described here has three centrifugal compressors and three reciprocating. It supplies a mine in New Brunswick.Compressed Air and Power ConsumptionFigure I and Figure 2 provide graphs of air consumption and pressure changes based on the owner's data.During the typical two-shift operating day (Fig . I) in the non-productive shift (midnight to 8:00 a.m.), the consumption stays at a level of 9,000 SCFM. This corresponds to a pressure of 110 PSIG. Then, after 8:00 a.m ., the air consumption starts to increase and th e pressure decreases. Around 10:00 a.m., the consumption reaches its maximum level at 97 PSIG. Around II :30 a.m., the air consumption starts to decrease because of the production drop during the lunch break of the first shift. Pressure increases again up to 109 PSIG. After the break, consumption rises to its maximum level over 16,000 SCFM andpressure drops to 97 PSIG.Around 2:30 p.m., the air consumption drops sharply to 9,000 SCFM because of the production decrease to zero level. This drop results from changing of shifts. The pressure at this time increases again up to 110 PSIG. The second shift (2:30 to II :30 p.m.) is an alogous to the first.During the three-shift operating day, the break around 4:00 . a.m . and the shift change around 6:30 a.m. cause sharp drops in air consumption. The pressure for almost the entire night shift stays near 110 PSIG because the station is working with blowing-off even under the maximum consumption. The analysis of Figures I and 2 shows that the pressure varies with the air consumption changes. During non -productive time (non-production shifts , shift changes and breaks) or during the night shift, the total station capacity is proportional to the discharge pressure. By decreasing the level of this pressure up to 97 PSIG, the flow of the station may be decreased during the non-production time as follow s:"

Jan 1, 1980