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By James L. Kelly

Stripping of the Twin Buttes copper deposit started in 1965. Total material removed for the first 10 yr of operation is approximately 879 million tons. The sulfide concentrator has treated about 45 million tons. The Twin Buttes mineral zone was concealed under several hundred feet of recent alluvium. Beneath this post-minera1 cover, Paleozoic limestone, siltstone and quartzite, and Mesozoic metaarqillite, arkose, conglomerate, and volcanic rocks are intruded by an igneous complex of quartz monzonite and diorite. All rock units are erratically mineralized, principally with copper and molybdenum. Strongest copper mineral favors the Paleozoic calc-silicated limestone and siltstone, often preferential to individual beds.

Jan 1, 1978

By William Kent

A MOST startling and as yet unexplained, failure of steel boilerplates, in two different sets of boilers, is reported in a paper by Arthur J. Maginnis, published in the London Engineer, December 11th, 1885, and reprinted in the American Engineer, January 14th, 1386. The facts of the case, as condensed from Mr. Maginnis's paper and from a number of letters in the subsequent issues of the Engineer, are as follows: 1. The material used for two different sets of boilers on two different steamers, each set consisting of three circular boilers with horizontal steam-chests, passed all tests required by the Board of Trade

Jan 1, 1886

By E. P. Pfleider, W. D. Lacabanne

Rotary percussive drilling, vibro-drilling, vibro-rotation drilling, rotary pulsating drilling-all names that mean the same thing-are gradually appearing in mining literature. What is rotary percussive drilling? It is a combined system superimposing a rapid percussive impact on a continuous rotary action in an attempt to utilize the most desirable features of both methods. At present single and multiple carriage-mounted rotary percussion units are being used in the European coal mining regions. One well engineered unit is the Hausherr "Albo" rotary percussive drill, utilizing two alternately operating percussion pistons, and another is the multiple-unit, jumbo-mounted Salzgitter machine. Niisse & Grafer also manufacture rotary percussion drills.

Sep 1, 1955

By F. S. McNicholas

In the first big blast at Climax, a "loop back" (three-wire system) was used (Fig, I), with the idea of securing a wiring system that would give to all series the same amount of current. Single-phase, 60-cycle, 13,800-volt power was furnished to the blasting transformers, each of which has a rated capacity of 600 amp. at 480 volts. Two blasting leads were taken from these transformers, giving a blasting current of single phase, 60 cycle, 480 volts, with an instantaneous capacity of more than 600 amp. The blasting switch was on the secondary leads from the transformers, to avoid lag in energizing them.

Jan 1, 1940

By F. S. McNicholas

In the first big blast at Climax, a "loop back" (three-wire system) was used (Fig, I), with the idea of securing a wiring system that would give to all series the same amount of current. Single-phase, 60-cycle, 13,800-volt power was furnished to the blasting transformers, each of which has a rated capacity of 600 amp. at 480 volts. Two blasting leads were taken from these transformers, giving a blasting current of single phase, 60 cycle, 480 volts, with an instantaneous capacity of more than 600 amp. The blasting switch was on the secondary leads from the transformers, to avoid lag in energizing them.

Jan 1, 1940

By Joseph N. Morrison

A comprehensive solution is offered to the problem of dust emissions at belt conveyor transfer points. Details of enclosure design are discussed and a straightforward procedure for calculating required dust control exhaust volume is presented. Many design variables are taken into account which heretofore have been commonly ignored or inadequately considered. These include belt widths, belt speeds. enclosure openings, material flow rate, material bulk densities, material lump sizes, height of material fall, material temperature, and ambient air temperature. All of these questions are handled by means of a "fill-in-the-blanks" type of calculation form, permitting quick, reliable solutions by relative "non-experts."

Jan 1, 1972

The Committee appointed by your Board of Directors to nominate Officers for the Institute for the year 1915 invites the participation of all members in the nominations. The suggestion of names for the various offices will be appreciated and given full consideration when making the selection of candidates which this Committee will recommend. The officers to be elected at the annual meeting in February, 1915, are: One officer, known as Director and President. Two officers, known as Director and Vice-President. Five officers, known as Director. The attention of members is called to Articles V and VII of the Constitution, and to By-Law XIII, which reads as follows:

Jan 6, 1914

THE papers presented by the Institute of Metals at the Detroit meeting in September, 1926, and the New York meeting, February, 1927, will be issued soon in one volume and mailed to all members of the Institute of Metals Divi-sion of this Institute. The, annual lecture given by Cecil H. Desch will begin the volume and the discussion occurring at the sessions, as well as subsequent written discussions, will be appended to each paper. The volume will contain about 600 pages, and will be sent without charge on request to any member of the Institute. The pre-subscription price to non-members is $5.

Jan 4, 1927

By Fredrick C. Kruger

Risk capital for mining ventures becomes harder to get each year as the costs for exploration, construction and money continue to skyrocket in today's inflationary economy. Because of this and because mining prospects must compete for the same dollar as many other needs of a diversified company, then the success or failure of any new proposal depends on how well its return on investment compares with all other capital requests. Mr. Kruger presents case histories showing what it costs to explore for new mines, how many of these prospects reward their promoters with success and how well some of the more famous mines have paid off.

Jan 9, 1969

By John J. Theiler

Early in 1963, the Inspiration Consolidated Copper Co., at Inspiration, Ariz., began a program to make automatic the lubrication of several critical points on their KW Dart 37SL haulage trucks. Prior to installation of the automatic lubrication system, all the haulage trucks were serviced by hand every three shifts. Now, with automatic lubrication, the service period has been extended to four shifts. What are the principal benefits to be expected from such a system? 1) Uninterrupted production; 2) extended machinery life; 3) good housekeeping; 4) lower maintenance costs. Of these points, the most important to truck maintenance are extended component life and lower maintenance costs.

Jan 5, 1965

Efficient energy utilization in the electrolytic zinc process, relative to other zinc processes, is one of the reasons for its wide adoption in recent years, says John D. Siddle, zinc plant superintendent at the Bunker Hill Co., Kellogg, Idaho. Designers and operators of electrolytic zinc plants have pioneered process improvements, new equipment, and operating techniques to conserve energy. As energy costs increase it the future and competitive pressure mounts against less-efficient producers, these energy-saving improvements will he regarded as necessary for economic survival. Plant designers and operators should not lose sight of the savings in operating costs possible through intelligent utilization of all available forms of energy.

Jan 11, 1977

By Harold V. Pearce

The fire which occurred in the fall of 1906, at the works of the Boston & Colorado Smelting Co., Argo, Colo., destroyed entirely the gold- and silver-refinery of the plant, and in view of the development of modern practice in the refining of copper-mattes, etc., the management decided that it would be inadvisable to rebuild that part of the works for the continued use of the process which had been conducted therein for so many years as a metallurgical secret. This decision probably removes altogether from the sphere of practice the '(Pearce" method for the separation of gold. At all events, it removes the busi-

Jan 1, 1909

By Thomas E. Howard

Scientific research in mining has a comparatively short history. So long as it was possible to maintain adequate mineral supplies by long-established methods, there was little need for the scientific approach. That the end of this comfortable situation is at hand is evinced by the variety and rapidly growing amount of mining research in progress all over the world. The pattern of development of mining research in other countries shows that it started only after a problem became critical. Therefore, the work generally has been short range and usually concentrated on a specific problem. An example is the preoccupation in western Europe with the problem of strata control.

Jan 1, 1962

By B. R. Coil

One executive writing on capital equipment re- placement stated: "We keep extremely close watch over repair costs and when we reach the point of uneconomical operation, we replace the machine." This, of course, is most elementary, but a very basic premise. However, it seems advisable to set forth several equally obvious principles, so that all discussion will start from the same point. The subject is intended to deal with the point of uneconomical operation due to high operating costs in general and high repair costs in particular. This is not concerned with a similar problem of high costs because of an insufficient number of machines, be they trucks, shovels, or dozers.

Oct 1, 1955

By Chester B. White

ARGENTINA is a country that has never been properly prospected. This is my settled conclusion after reporting on mines in this country ever since 1914, crossing all the mining provinces from Chubut, in the South, to the territory of Los Andes, in the North, chiefly on muleback. It is difficult and costly to get from one district to another. Apart from petroleum, some mineral discoveries have been made but they have been the result of casual rather than systematic work. In Neuquen, Mendoza, San Juan, Cordoba, La Rioja, Catamarca, and Los Andes attempts at mine development have resulted in failures, involving in each instance several million pesos.

Jan 1, 1937

By Sherwin F. Kelly

THIS is intended as a simple review of the principles and practice of geophysics, so will not be of interest to the geophysicist, who is hereby warned of its elementary character. The engineers for whom it is written are those who, having glimpsed the formidable formulas and discussions of the geophysicists, give all publications on the subject a wide berth. For a few years now the geo-physicists have had a tendency to be ingrowing at their meetings, going deeper and deeper into theory and instrument construction, and forgetting to present the topics that would interest the practicing engineer who desires merely to know how geophysics can help him, not why.

Jan 1, 1934

Two career employees of the US Dept, of the Interior, in a recent study, indicated that by the end of 1974, 73% of all public lands had been entirely or partially closed to exploration and development of essential resources for leasable minerals and 67% had been similarly restricted for locatable minerals.1 This has come about because of the lack of coordination within the executive branch and between the executive and legislative branches of the federal government and without regard for the cumulative, depressing effect on future domestic mineral production. Much of the withdrawn land is felt to have great potential for discovery of significant mineral deposits.

Jan 5, 1976

By M. D. Cooper

UNDERGRADUATES in mining engineering may be prepared for work by giving them sound instruction in the courses generally considered essential to the profession. The industry is not deeply concerned about the details of those courses. The average man in the coal industry does not wish to insist upon a rigid program. Therefore, he differs little from those in the teaching profession who evidently are not unanimous in their opinions, or all college catalogs would be alike. For the good of the profession, it is just as well that there should be differences in regard to details. It appears that students graduating in mining engineering from the accredited institutions receive similar instruction.

Jan 6, 1950

By John V. Beall

On January 1, 1948, we boarded the cage at 7 a.m. and were dropped to the 900 level of the Brunswick shaft. The previous evening, we had attended the New Year's party at the Miners' Guild Hall and as this soireée had not disbanded until the small hours of the morning, we had only had about two to three hours sleep. At the 900 level station, we fell in beside our mining partner, a Cousin Jack, who was known by all as Porky. Porky didn't say anything as we plodded down the drift, we didn't say anything either-in fact there was little conversation by anybody.

Jan 1, 1971

Coal was produced in this state, by white men, at an earlier date than in any state west of the Mississippi River, and for many years its production was larger than that of any state in that area. The coal immediately adjacent to St. Louis was mined commercially earlier than elsewhere because of a ready market which could be reached by teams. Generally the coal seams are more or less "spotty" in character, and in many places openings made in thick coal could only be mined for a few years. All of the data available from state survey reports, county histories and a few other sources are shown in Table 66.

Jan 1, 1942