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By Charles M. Brinckerhoff

The Potrerillos mine of the Andes Copper Mining Co., a subsidiary of Anaconda Copper Mining Co., is 100 miles east of the coast town of Chanaral, in the Province of Atacama, Chile. In December 1926, the plant was placed in operation and has operated continuously ever since. Block caving is the only mining method used, as it is especially suited to the grade of ore, the position and shape of the ore bodies, and the character of the ground. At the present time there are three haulage levels, which handle oxide and sulphide ores, and production from them averages 31,000 short tons daily. The purpose of this paper is to describe the layout, equipment and systems used on the gathering or main haulage levels. Haulage Layout Because of the shapes of the ore bodies, their distances from the dumping pockets

Jan 1, 1946

By Donald F. Kennedy

During the past several years Climax Molybdenum Co. has been engaged in testing various types and sizes of hollow drill steel. The majority of tests have been on 7/8-in. hexagon st.ee1, inasmuch as it represents approximately 70% of total drill steel consumption at the Climax operation. Prior to December 1960, tests on 7/8-in. hexagon drill steel were conducted on steel with a forged collar and, in most cases, with a threaded bit connection. Through these tests and research, some improvement in steel life was achieved by making changes in heat treatment, design and alloying constituents. However, during that month, research and testing commenced on a rubber collar which was designed to replace the forged collar on 7/8-in. hexagon drill steel. Manufactured by the LeRoi Div. of Westinghouse Air Brake Co.. the collar. is very simple in design, consisting of a 1 ½ -in. diam steel cylindrical sleeve 2 in. long, containing a bonded rubber insert and attached to the steel with an epoxy cement

Jan 8, 1962

ASIDE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has four awards it may make annually, as fol¬lows: the Robert W. Hunt Medal and Prize, the J. E. Johnson, Jr., Award, the James Douglas Medal, and the William Lawrence Saun¬ders Medal. ROBERT W. HUNT MEDAL AND PRIZE The partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules 1. The award shall consist of two prizes: first of a gold medal, second of a sum of money; a certificate to accompany each prize. The money prize shall not be awarded to a member over 40 years of age, but under unusual circum¬stances, both prizes may be allotted to one person provided that he is not over 40 years of age. In general it will be understood that the Committee shall award the money- prize to the younger men, rather than the medal.

Jan 1, 1923

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 George Rice

SINCE my earliest recollection, the coal business has been in a state of unrest. It has always been a matter of bewilderment to the serious thinking, the instability of this most important industry; second only to agriculture in its effect on the great development of this country, and even more important in certain aspects, because without fuel railroads could not run, agriculture could not get its products to market, nor would the great manufacturing enterprises have been possible. I will not attempt to discuss the present serious -labor dispute or similar disagreements of the past; in the settlement of which more or less successful attempts have been made to equalize, temporarily at least, natural conditions through "joint agreement" as to prices paid labor; but will confine my views to the general underlying conditions of which the disputes are symptoms, and try to show how these must be remedied before there can be any hope of stabilizing conditions.

Jan 5, 1922

By Garth M. Crosby

Seven mines with important production records in the Coeur d'Alene lie adjacent to the Gem stocks -the Frisco (Gem), Hercules, Interstate, Rex (Sixteen to One), Success (Granite), Sunset, and Tamarack. Old records are incomplete, but avail- able data given in Table I show these mines have produced 10,550,721 tons of ore containing more than 50 million oz of silver, more than 1.5 billion lb of lead, and about 1 billion lb of zinc (approximately 1.25 million tons of lead and zinc combined). Average ore grade is 4.8 oz of silver per ton, 7.2 pct Pb, and 4.6 pct Zn. This impressive production represents about 12 pct of the District's yield. At present metal prices, with modern beneficiation, the gross value would be more than $400 million.

Jan 7, 1959

By Marshall B. Standing, Donald L. Katz

DENSITY data are reported on 15 saturated hydrocarbon liquids in the range of 35° to 250°F. and 1000 to 8220 lb. per sq. in. The apparent liquid densities of methane and ethane are shown to vary with the density of the system in which they are present. A method is proposed whereby the densities of liquid hydro- [ ] carbon mixtures containing both methane and ethane in solution may be computed at elevated temperature and pressures within the accuracy of usual engineering computations. A method of computing the shrinkage of crude oils based upon the gas-oil ratio, gas analysis, and crude gravity is outlined. INTRODUCTION The densities of naturally occurring liquid hydrocarbon mixtures are important [ ] in many petroleum engineering computations. Calculation of the shrinkage of a subsurface sample of crude oil as the natural gas is evolved is one example of the use of liquid-density data. Sage, Hicks, and Lacey5 have presented a method of computing the density of hydrocarbon liquid mixtures based on partial molal volumes. Katz1 has indicated a method based on the principle of additive

Jan 1, 1941

Robert H. Richards, Boston, Mass.: Mr. Goodale calls attention to the difficulty of obtaining clean tailings from the jigs which are fed by the spigots of the hydraulic separator. This difficulty is universally encountered. The Lake Superior copper mills practically overcome it by running the beds of those jigs loose, carrying into the hutch all of the available copper and some sand. These hutches are again jigged upon threesieve Collom jigs, where the treatment is very slow and gentle; and on the successive jigs lighter and lighter bedding is used. The last sieve is run thin enough to let some sand into the hutch. With these precautions most of the free copper is extracted, as well as a fair proportion of the included copper.

Jan 1, 1897

By David S. Butts

There are many solution mining operations that use solar ponds as a mineral recovery step. Other locations in the world are now under investigation to recover minerals by solution mining but require the cheap energy of solar ponds to make the recovery viable. This paper shows a step-by-step material balance system that can be used in both simple and complex solar ponds. Use of this system will help the engineer determine if solar ponding efficiency can be improved or if solar ponding will work at all with a given set of conditions. Even the most complicated solar pond can be reduced to six flow streams. These are (1) feed, (2) exit, (3) leakage, (4) entrainment, (5) salts, and (6) evaporation. The equations developed in this paper will allow the solar pond engineer to easily evaluate the effect of each of the flow streams on the mineral production of a pond or pond complex.

Jan 1, 1985

By Graham MacFarlane

The eastern coal-field of Kentucky covers about 11,000 square miles of territory. On the east and south it extends to the State lines of West Virginia, Virginia and Tennessee. Its western boundary may be roughly described as an irregular line beginning at the Ohio river, in Greenup county, thence through the counties of Carter, Menifee, Wolfe, Estill, Jackson, Rockcastle, Pulaski and Wayne, to the Tennessee line. The changes in the rock-intervals and in the coal-seams from the northeastern end of the field to the south and southeastern end are so great that no satisfactory identification of the coals has yet been made, and the correlation of the Kentucky coals

Jan 1, 1896

By G. L. Jr. Spencer

THERE is no question as to the importance of the part played by the retort in modern zinc smelting. A satisfactory retort should have properties that will result in resistance to slagging action and fire cracks, and have no tendency, or at least, only a small tendency, to soften and bend under furnace heat. The life and cost of a retort also are extremely important factors. The trend in zinc smelting during the past few years has been toward longer retorts and higher charge density. This is caused by the fact that the diameter is limited to 9 or 10 in. because of heat penetration difficulties in larger sizes. Consequently, increasing the length of the retort and density of charge offers the only practical means of increasing the amount of zinc produced per retort. The stiffness of a retort perhaps is the most important factor, as slag accumulates in the bottom of a retort which has sagged and very quickly cuts through, often ruining the retorts below. The development of the high-silica retort is a result of the demands made by the trend toward heavy charges.

Jan 1, 1931

By Herbert Herman, M. E. Fine

THE first decomposition product of a supersaturated aluminum-rich A1-Ag alloy at low tempera- tures is Guinier-Preston zones.'-, The zones are ideal and each consists of a spherical shaped silver-rich cluster about 16 A in diam syrounded by a silver-poor shell approximately 72A in diam.' The composition of the two regions is not known with certainty., After quenching from the solution anneal, these zones form rapidly on aging at temperatures as low as -30°C.5 The rate of zone formation increases with aging temperature; the activation

Jan 1, 1961

By Walter Gaby

L. C. GRATON, Cambridge, Mass.-May I ask, in connection with one point in the summary, to what extent the author regards actinolite equivalent to tourmaline as an index of high-temperature and presumably magmatic conditions of deposition of the accompanying sulphides? W. E. GARY.-I merely advanced the idea that the mineral actinolite might have some such significance. In the copper deposit at Braden in South America, the ore occurs in an andesite breccia which is cemented by a matrix of sulphides, quartz, and tourmaline. Tourmaline is a high-temperature mineral, and when we find it associated with ores, these are regarded as having come from a volcanic or deep-seated source, hence a primary hypogenetic deposit. Thus we can count on greater continuation of the ore with depth than in some other kinds of deposit, and I thought that the actinolite, being also a high-temperature mineral, might have some such bearing in the case of Mount Morgan. I did not advance this idea as a final conclusion from a study of such phenomena, but thought that it might bear some discussion in view of the fact of the peculiar occurrence of this mineral in a notable orebody. It also occurs with the copper ores at Ducktown, Tenn., and in both cases may only be due to general regional metamorphism.

Jan 12, 1916

By J. Ehner Thomas, M. D. Gould

Until four years ago the market price of oil securities moved directly and immediately with the general list. This point, was first developed by the senior author in 1924 while making a statistical study of the relative movement of oil securities and the general market. Plotting the monthly averages of 17 oils against 233 industrials disclosed the sur- prising relationship shown in Fig. 1. The traditional vagaries of the oil business, the wide fluctuations in current supply and resulting abrupt changes in crude prices nevertheless produced no movements in the market price of oil securities as a group, which departed notably from the movements of the general market. Obviously general business conditions did not always change when and as conditions in the oil industry changed; clearly the fluctuations of

Jan 1, 1929

By T. F. Witherbee

The Iron Mountain, situated three-quarters of a mile NE. of the limits of the City of Durango, rises abruptly from a level plain, and trends N. 83' E. Fig. 1 gives a view of the mountain, with the company's iron-works. There are indications that the vein or deposit of iron-ore extends also about two leagues across the Murca ranch, in the same general direction. The Iron Mountain proper is divided into two great lenses by a horse of cantera or eruptive rock, some hundreds of feet in width.

Jan 1, 1902

By August E. Vandale

Mining of the Freeport and Pittsburgh coal seams in the Pittsburgh vicinity dates back more than 100 years, and Consolidation Coal Co., or its predecessor, Pittsburgh Coal Co., has been actively mining in the area since 1900. Over the years, Consol has acquired good legal title to the coal lands purchased from individual farm owners, with broad mining rights, and in 98% or more of its title holdings, the company has a complete waiver of surface damage or the right to subside the surface land. (Titles in Pennsylvania can be in three forms: title in fee; title to the mineral; or mining rights permitting the removal and extraction of the mineral with or without waiver of surface damage.) In the early history of Consol, individual farms overlying the seams were purchased from land owners. Many of these titles severed the coal estate from the "in fee" title, and mining rights with waiver of surface damage were conveyed in the original severance deed. In this manner, Consol was able to put together its large mineable coal reserves. Consol has practiced "full recovery" mining as far as practical from its early years of hand loading to the recent era of mechanization.

Jan 9, 1967

By Roger B. Alke

INTRODUCTION Request to Mine Beneath Bridge The Jakes Run Bridge is a reinforced Portland concrete arch filled bridge located on WV Route 7 near Pentress, WV. The bridge has a span of 22.9 m (meters) and a height of 4 m above normal pool elevation to the underside of the center of the arch (See Fig 1). The bridge is a two lane structure with a width of 6.86 m. The structure is over 50 years old having been built in 1929 and is owned by the Department (WV Department of Highways). [ ]

Jan 1, 1984

By Thomas Connolly

The Homestake Mine is situated in the northern portion of the Black Hills of South Dakota in a series of steeply dipping and highly folded Precambrian Rocks. The ore bodies are localized along plunging anticlinal and synclinal folds which are locally called "ledges." The gold bearing ore is confined mainly in the Homestake formation which is an iron-magnesium carbonate series of rocks. The individual ore bodies are pipe or lense-shaped zones which plunge 30º to 75º from the horizontal. These ore bodies range from 10 to 100 feet wide and 50 to 400 feet along the strike. Gold values are erratically distributed in a gangue consisting of cummingtonite schist, sideroplesite schist, quartz, pyrrhotite, arsenopyrite, chlorite schist and ankerite. Usually the ore bodies dip at 70° to 80º and often have folded shapes like "fish hooks" or "troughs." Ore grades must be determined by extensive sampling and all mining is based on assay control.

Jan 3, 1974

By Gerard A. Flierman

INTRODUCTION There is a lot of discussion about the relative merits of sinter and pellets as components of a BF-burden. Many people claim that sinter is to be preferred and that the percentage of pellets in the burden must be restricted to 20%. During BF-trials in IJmuiden various amounts of pellets having various basicities were tried. It was concluded that there were no significant differences in furnace performance. Consequently the choice between sinter and pellets must be based on the local manufacturing costs (1). Table 1 gives a summary of the pellet experience in IJmuiden. [ ] Because the BF-trials were relatively short, a survey of published BF-operating data has been undertaken to investigate if differences between a sinter and pellet based BF- practice could be found. The comparison of BF-operating results has been restricted to coke rate and productivity.

Jan 1, 1977

JEROME ALEXANDER.-All of you undoubtedly know that a microscopic examination of metals will reveal many things; but we should go further than just simply using a low- or medium-powered- microscope and seek the reason why grain size varies under different conditions. When we get below the limits of the ordinary microscope, we enter the so-called colloidal field, which means that we are dealing with aggregations of matter that approximate, say, 100 millimicrons. The colloidal dimensions average approximately 50 millionths of a millimeter and extend down to about 3 µµ. This, of course, is beyond the range of visibility in the ordinary microscope. Just to give you an idea of this matter, if 1 cu. in. of platinum is reduced to a sheet five molecules thick, it will cover 7 acres; you can imagine the amount of surface involved when metal, or anything else, is subdivided to so high a degree. Of course five molecules thick is a little below the limits of the colloidal dimensions. The statement is made in the paper that "metals and alloys might be

Jan 4, 1919