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By L. A. Cowan

IF the elements of personality be those characteristics in which humans differ, and if this definition be applied to the purchasing department for the Climax operations in Colorado, it must he concluded that this department has no distinguishing traits that would give it a departmental personality different from that possessed by the similar department of any progressive mining enterprise. Or, one may go further by stating that the rudimentary functions of any purchasing practice employed principally in the acquisition of maintenance, repair, and operating supplies are much alike, whether or not the industry involved be mining or milling. However, in the fact that the principal purchases of a mining company are materials for maintenance and repair and consumable operating supplies lies that essential characteristic which differentiates mining and milling purchasing functions from those of the manufacturer, the fabricator, or the ordinary processor.

Jan 1, 1946

By W. C. McClain

In the design of underground excavations, rock mechanics considerations are nearly always based on an elastic behavior of rock. Most rocks do exhibit a certain amount of elasticity, and the application of principles and concepts of elasticity to rock mechanics problems has been largely responsible for progress in the field over the past 10 or 15 years. No doubt the theory of elasticity will remain the most useful analytical tool available for both the design of underground openings and the interpretation of phenomenological data.

Jan 1, 1967

By Ralph L. Erickson

The discovery of a Carlin-type gold deposit at Cortez, Nevada, in 1966 can be attributed directly to the use of geochemical exploration techniques. Most mineral deposits owe their discovery to geologic concepts, geologic analysis, and luck, but at Cortez, geochemistry as an exploration tool played the clearly dominant role in discovery. Of course, the economic significance of the discovery had to be determined by exploration and development drilling. The story of the discovery began in 1959 when field work was initiated on a new project, "Geochemical Halos Utah and Nevada," by R.L. Erickson and A. P. Marranzino for the US Geological Survey. The Cortez district was selected for geochemical work because it was an area with good geologic control where we could address the problem of how to prospect in barren outcrops for concealed ore deposits in potentially favorable structures (buried thrust zones) or favorable host rocks in the subsurface. Geologic mapping of the Cortez 15-min quadrangle, just being completed by Gilluly and Masursky (1965), showed that the quadrangle contained excellent exposures of both the upper and lower plates of the Roberts Mountains thrust fault, a major structural feature of north-central Nevada. Roberts (1960) had noted that a number of mining districts were associated with windows in the thrust. In 1959, Erickson and Marranzino did some reconnaissance rock sampling and spring-water sampling in the siliceous clastic rocks of the upper plate of the thrust. Results of this reconnaissance prompted a full-scale sampling program in 1960 in the upper plate rocks on the west flank of the Cortez window. Results of the investigation showed that anomalously high concentrations of metals occur in the upper plate rocks, and further, that the distribution of metals is fault controlled and shows a pronounced zoning pattern (central copper zone; intermediate zinc, copper, and lead zone; and outer arsenic zone). The anomalies were interpreted as primary leakage halos that originated from metal occurrences in the thrust zone or in carbonate rocks below the thrust and moved upward along normal faults that cut both upper and lower plate rocks. Erickson gave a talk about these anomalies in the summer of 1961 to the local AIME Section in Reno, Nevada; two short reports were published that year-" Geochemical Anomalies in the Upper Plate of the Roberts Thrust Near Cortez, Nevada" (Erickson et al., 1961) and "Hydrogeochemical Anomalies in Four Mile Canyon Near Cortez, Nevada" (Erickson and Marranzino, 1961). These releases prompted blanket staking in the area by several small companies. In 1963, geologic and geochemical mapping were started by the USGS in the lower plate carbonate rocks of the Cortez window west of the quartz monzonite stock at Mount Tenabo and north of the old townsite of Cortez. The results of the work showed anomalously high concentrations of arsenic, antimony, and tungsten in jasperoid, fracture filling, and shear zones in Silurian and Devonian carbonate rocks. The anomalous area was about 1.6 km (I mile) long and 300 m (1000 ft) wide. A brief report, "Geochemical Anomalies in the Lower Plate of the Roberts Thrust Near Cortez, Nevada" (Erickson et al., 1964a), was published in 1964. During this same time period, 1959-1964, several exploration or mining companies were active in the general area (chiefly mapping geology and acquiring property). In 1964, American Exploration and Mining Company (Amex) concluded that the entire Cortez district was worthy of an extensive exploration effort involving drilling as well as geologic, geophysical, and geochemical studies. To carry out the program, Amex formed a joint venture group with the Bunker Hill Company, Vernon Taylor, Jr., and Webb Resources. Their early efforts were directed to the upper plate rocks and to the lower levels of the old Cortez silver mine. The group also drilled some shallow rotary assessment holes adjacent to the area of the arsenic, antimony, tungsten anomaly in lower plate carbonate rocks described in Erickson et al. (1964a). Assay results from these holes offered little or no encouragement to the joint venture group. Splits of these drill samples were made available to the USGS. In order to enhance any metal content present in these rocks and to determine the mineral residence of any metals detected, heavy-mineral concentrates of each 3-m (10-ft) sam-

Jan 1, 1985

By R. J. Reynik, F. R. Meeks

IN the classical paper1 of Mehl and Rhines entitled "The Rates of Diffusion in the Alpha Solid Solutions of Copper", the authors state: "It has been mathematically demonstrated that the treatment of the data as though the diffusion were taking place between two flat plates instead of radially in a cylinder has no appreciable effect upon the results. Were the bars of a much smaller diameter, a modification of the analytical treatment would have been required." Unfortunately, the errors in the reported concentrations are much too large to neglect, as shown in the results below. A planar treatment of diffusion data assumes that the reference planes separated by a nominal distance (AX) have identical areas. An adjustment must be made on the concentration data should the successive diffusion planes differ in area. The Mehl-Rhines' diffusion samples were cylindrical with copper electroplated onto copper-based alloys. Successive surface areas through which diffusion occurs are in the ratio ri/r1, where ri is the radial distance between the center of the sample and the center of the i th shell to which the host (alloy) atoms diffuse, and r1 is the radial distance between the center of the sample and the center of the innermost (i = 1) experimentally reported shell from which the alloy atoms diffuse. Hence, ri/r1 (i = 1, ..., n layers) is a dimensionless correction factor to be multiplied by the reported concentration data before planar-data analysis is attempted. In the forty-seven samples reported, the original interface between the copper alloys and the electroplated copper was located at a mean distance of 8.255 mm from the center of the samples. The successive layers, machined off the samples, were approximately 0.0762 mm thick. The distance (xi) at which concentration (ci) was reported was always a distance measured with respect to the original interface, that is, with respect to the fixed distance of 8.255 mm. Hence, the as yet undiscovered Kirkendall Effect was precompensated. The values of ri and r1 are therefore given by ri = 8.255 + xi and Y, = 8.255 + x,. The illustrative table below lists the position xi (mm), ri (mm), the value of ri/r1, the reported concentration (ci) in weight percent (only valid for radial analysis of data), and the corrected concentration [c'i = (ri/r1)ci] in weight percent (only valid for planar analysis of data). Similar tables can be constructed for the remaining forty-six samples. The corrected data can be used to re-evaluate the diffusion coefficients for the reported systems.

Jan 1, 1965

By A. M. Riddle

GROWING out of the nation's most colorful era of railroad building, and with the vision of early pioneers who foresaw a great future for the Western Empire, the Colorado Fuel & Iron Corp. set as its objectives The establishment and building of colonies, towns, schools; industries such as coal mining, iron making and manufacturing works; canals and roads. This was the beginning of CF&I in the year 1872, and from this small western beginning has grown a company that has achieved national importance, ranking ninth in size in steel producing capacity, with over 22,000 employees and operating 14 plants in strategic locations throughout the United States.

Jan 11, 1953

By M. E. Gershon

The development of long-term plans and schedules for strip mines now faces many companies, especially those developing large properties in the West. The rule of mining the lowest strip ratios first, while delaying equipment acquisitions and recouping investment the fastest, sometimes creates the situation where stripping ratios are too high in the latter years of mining operations. A program concept taking life of mine return on investment into account is developed in this paper to optimize mine scheduling and equipment acquisition. In addition, quality considerations (heat content, ash, sulfur, and washability) can be considered by including the appropriate blending constraints to meet contract requirements.

Jan 1, 1984

By G. H. Jardine

In future years, decision makers in the coal industry will make more and more decisions based on information from computer-based models. Whilst the use of such techniques will provide many advantages for coal companies, particularly in terms of efficient utilisation of their human resources, it is equally important for the decision makers to have an awareness of the limitations inherent in each particular computer-based model being used to provide information for the decision making process. A recommended procedure for identifying such limitations - by analysing the 3 major elements of the model - is presented. The human aspects of increased use of computer-based techniques are emphasised throughout the paper.

Jan 1, 1983

By C. K. Leith

THE resolution presented at the Annual Meeting of the A.I.M.E., calling on Congress to provide now for postwar accumulation of mineral stock piles under Government control, expresses, I think, the nearly unanimous view of the mining industry. As a result of the trying experiences of the first World War, Mr. Baruch, in his report of Dec. 24, 1919, to the President, urged that steps be taken at once to ensure adequate supplies of raw materials for future emergency. In the twenty years that followed, the same program was vigorously urged on Congress by many individuals and agencies, public and private, including the Secretaries of War and Navy, many members of Congress, the Bureau of Mines, the Planning Committee for Mineral Policy appointed by President Roosevelt, the A.I.M.E., the Mining and Metallurgical Society, and others.

Jan 1, 1943

By Harold Vance

The Lafitte field, the largest oil reserve in South Louisiana, is in Jefferson Parish, some 25 miles due south of the City of New Orleans. The discovery well, The Texas Company's No. I, Louisiana Land and Exploration Co., in the southeast corner of sec. 19, T. 17 S., R. 24 E., was completed on May 15, 1935. The initial production of this well was 960 bbl. of 34.9º A.P.I, gravity oil per day, through 1/4-in. choke, with a tubing pressure of 1600 lb. per sq. in. Producing depth was 9558 to 9572 ft., the total depth being 9572 feet. The development of the field has been at the rate of three to eight new producing wells per year. Up to Jan. I, 1944, 60 producing wells and three dry holes had been drilled, while two of the original producing wells had been abandoned, Although the field is not unitized, The Texas Company was the sole operator in the field until the Lafitte Oil Co. completed its NO. I Jefferson Parish, near the center of the west line of the NW/4 sec. 20, T. I7 S., R. 24 E., on July 27, 1941. No additional wells have been drilled by the Lafitte Oil Company. Drilling and WeLl-completion Practices All drilling operations have been conducted with the steam-driven rotary equipment mounted on submersible barges. A canal is dug to the well location and the drilling unit is floated into position. The seacocks are then opened and the barge settles to the bottom. After the well is completed, seacocks are closed and water is pumped out of the barge. This procedure permits the barge, with drilling equipment still in place, to be floated and moved off the location. The conventional open-hole and the gun-perforation method of completing wells has been used in this field. Where possible, the initial completion is from the deepest 'sand and recompletions are made progressively up the hole, by plugging back with cement to the upper sand and gun-perforating opposite the new sand. The oil string usually is 7 5/8 in., 26 to 34-lb. casing. Three wells have been completed using 9 5/8-in. 44-lb casing set below 10.000 feet. Fig. I shows the completion and recom-pletion practices on one well in the field. This figure also shows the relative locations of the different producing sands as shown on the electric well log. Structure The structure is an elongated dome, cut by two north-south faults, which divides the field into three segments. The west segment is the highest structurally and contains most of the recoverable oil and gas. The center segment is less important and the east segment is of little value. Figs. 2, 4, 6, 8 and 10 are depth contour maps on top of the five main producing sands in the field. These maps show the relative size of the five reservoirs and the

Jan 1, 1945

Jan 1, 1968

By George J. Young

Jan 1, 1911

By Edward W. Parker

THE agreement of September, 1922, between the anthracite operators and the United Mine Workers of America, which followed the 54.5 months strike during the summer of that year, contained the following provision : The parties unite in a recommendation to Congress that legislation be forthwith enacted creating a separate anthracite coal commission with authority to investigate and report promptly on every phase of the industry and the parties hereby ask the President to request the enactment by Congress of the recommended legislation. The continuance of production after Aug. 31, 1923, shall be upon such terms as the parties may agree-upon in the light of the report of the Commission.

Jan 1, 1924

By R. Ward Grosz

Reasonable and timely solutions to the complicated mathematical calculations involved in the mine planning, economic evaluation and slope stability studies related to the Ruth Mine would not have been feasible without the modern digital computers. The Ruth Mine was a prosperous underground copper operation in east central Nevada from 1915 to 1948, when rising mining costs finally exceeded the value of the ore. A substantial reserve of porphyry copper remained in the ground, but until recently all economic evaluations indicated that it was at best a marginal operation and a relatively poor risk of capital. There has been a steady progress in improving all aspects of surface mining since the first steam shovel started stripping overburden; however, developments in just two rather specialized areas proved to be critical in changing the Ruth Mine from a reserve of mineralized rock to an economically attractive orebody. One involved the progress made in recent years in the science of slope stability. Applying the latest techniques in this field to mine planning resulted in reducing the stripping ratio from 6.0:l to 4. 2:l. The other major factor was the efficiency and cost performance of large capacity haulage trucks which made it feasible to go down over 1100 ft. in an open pit and recover ore with a high stripping ratio economically.

Jan 1, 1969

Jan 1, 1967

Executive SCOTT TURNER, Chairman FREDERICK M. BECKET JOHN A. MATHEWS H. A. GUESS WILLIAM WRAITH Finance HENRY KRUMB, Chairman PAUL D. MERICA ROBERT E. TALLY Admissions JOHN M. LovEJOY, Chairman GEORGE D. BARRON ERLE V. DAVELER WILLIAM H. BASSETT W. D. B. MOTTER, JR. Alternates HENRY B. FERNALD F. JULIUS Polls AMOR F. KEENE

Jan 1, 1932

By P. E. Fitzgerald

ACIDIZING, as the terns is used in the petroleum production industry, involves the use of hydrochloric acid in predominantly limestone formations, resulting in the lowering of resistance offered to the flow of oil and gas through the oil-bearing formation, usually with resultant increased production. A number of articles have been written on the chemical treatment of oil and gas wells; a bibliography of these works will appear in Volume 123 of the Institute's TRANSACTIONS (1937), and a few other references are appended to this paper.

Jan 1, 1937

Jan 1, 1970

* A loan, perhaps as great as $100 million, from American insurance companies is about negotiated for development of Labrador iron ore properties. The program will call for a total expenditure of up to $200 million, including, as well as all mine development work, the power facilities, housing for mining personnel, and auxiliary equipment. * Mobile air compressors and a water tank, mounted on a 30-ton rubber-tired trailer and towed right up to the drilling crews, eliminates the need for expensive underground water and air pipe lines in the experimental oil shale mine operated by the Bureau of Mines near Rifle, Colo.

Jan 11, 1950

POSITIONS VACANT No. 157. Superintendent for roasting. and magnetic separating plant working on zinc concentrates. Must have mechanical experience and a working knowledge of electricity. Salary will depend on experience and results obtained. Location Canada. No. 155. Metallurgical chemist familiar with copper and steel for company just starting. Must have had technical education and practical experience with both metals. Salary moderate at beginning, but will be increased as business grows. No. 159. An experienced, up-to-date coal-mining engineer to open up and manage soft-coal mines in Spitzbergen, preferably a Scandinavian capable of handling Norwegian laborers. Employment beginning January.

Jan 12, 1916

By Frank L. Nason

RECENT explorations with a diamond-drill, originated and conducted by Mr. J. A. Van Mater, Superintendent of the Lehigh Zinc and Iron Company, have revealed some very important geological facts, which, it is believed, will be of special practical interest to mining engineers. During these explorations the writer was frequently called in consultation, and hence the facts here recorded are almost entirely the results of personal observation. The franklinite-deposit upon which the explorations were conducted has a long continuous outcrop. Figs. 1, 2 and 3 give a map and sections. Beginning at the extreme southern point,

Jan 1, 1895