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By E. L. WOOD

IN ATTEMPTING to summarize briefly the reconstruction of the Hecla plant since the fire, three important facts must be held in mind; namely: a hurry-up job with the shadow of an insurance company in the background; restriction of working space in the narrow Burke Canyon; and building two-thirds of the plant on a filled area. Construction work was carried on without interruption through the winter season. These adverse conditions have contributed many obstacles not ordinarily encountered in mining work. The first problems immediately after the fire were organization and policy; the-former to create an efficient construction crew out of a mining organization; the latter to determine the type and extent of surface plant to be built. The new crew was organized from a nucleus of mine employees, 25 per cent. of the old crew remaining for construction work. Permanent fireproof buildings were decided upon, the general arrangement of the new plant to be similar to the old one as far as possible, at the same time enlarging it 100 per cent. in anticipation of the demands which would be made upon it when the Star Mine began operating. Cleaning up the wreckage was a big job, the extent of which is indicated by the fact that 30 carloads of scrap iron and steel were moved off the property. In re-establishing transportation facilities at the plant, a previous disadvantage of a steep grade on the high line was obviated by excavating 1600 yd. of solid rock; the fire having destroyed all town buildings below, made this work possible.

Jan 1, 1924

By C. K. Leith

1 apologize for attempting to talk in a field in which 1 am by no means a specialist, but some of the problems brought up have much in common with other minerals. It touches the field in which we are all interested and it is a field in which our Mineral Inquiry has been giving special attention during the last two years. While it is the primary business, of course, of this Institute to consider the physical facts and technology of minerals, we now face the necessity of considering the minerd industry in its broader economic, social, and political relationships. We have run into a traffic jam—as though a load of hay had been spilled on the road. It makes no difference whether we are drivers or passengers, technical or nontechnical men, we have to get the load off the road before we can go farther. We are conscious of very many difficulties which are outside of the ordinary range of cost accounting or methods of mining or the usual thing with which we concern ourselves. We have extensive readjustments to make in our social and economic and political contacts. It is up to us to find out what is the matter. As a matter of fact, we do not know what is the matter in any comprehensive way. We have many suggestions as to difficulties here and there. Many people are working on the problem, but when the mineral industry as a whole is asked what is a reasonable course of procedure, what is its program, what would be a reasonable state or national policy, I think you will agree with me that we have no spokesman able to outline even a semblance of such a general policy. We sit back and criticize when somebody else steps in, as Governor Murray stepped in, and as many others of our state governors and legislators are stepping in, to do things which we do not think are reasonable. When they say, "What is a reasonable program? " we find ourselves caught napping. We have not agreed on a program. The other day in talking with one of the leaders of the western radical movement, I was twitting him on having no sound and comprehensive conservation program. He said, "What is yours, and what is the program of the mineral

Jan 1, 1932

A completely automated primary crusher is now in operation at Kaiser Steel Corp.'s Eagle Mountain, Calif., iron mine. The word "completely" is italicized to underscore its literal meaning- automation so thorough that even the control room for the crusher does not require a man to watch the flickering dials and lights. The automation of the unit is such that its operation, including starting and stopping, are controlled from the secondary crusher station. The crusher-a Symons 60-in. gyratory which can handle 3600 tph-features built-in safety devices that will turn the crusher off if oil pressure drops, if oil overheats, if bearing temperatures exceed permissible limits, or if parts of its electronic brain fail. According to reports, the worst that can now happen is a plugging of the crusher.

Jan 6, 1963

By Theodore H. Eyde

In the southwest porphyry copper province, the virgin prospect with good copper mineralization cropping out has disappeared. Future discoveries will require an increasingly sophisticated arsenal of exploration techniques and concepts. One of the latter, stratigraphic analysis, is a technique which is often overlooked. A surprising number of exploration geologists still think of porphyry copper deposits as occurring wholly within intrusive bodies such as quartz monzonite or granodiorite. Disseminated copper mineralization, though genetically related to intrusive rocks, can occur within both the intrusive and the intruded rocks. At present, as much as 30% of the total copper produced from disseminated copper deposits in the Southwest originate from the intruded rocks rather than the intrusive.

Jan 4, 1972

By W. B. Plank

The figures on enrollment in the engineering schools of the United States and Canada indicate that the total number of students in these schools for the current year, 1949-50, is about 10% less than it was a year ago. This year, 226,533 undergraduates and graduate students are studying engineering in the United States and Canada as compared with 249,913 students last year. These figures are taken from advance data in the Journal of Engineering Education for February 1950.

Jan 5, 1950

By R. L. Sebastian

ALUMINUM'S war history is the record of a successful race to expand facilities fast enough to meet the multiple increases in military requirements, principally for aircraft. From the beginning of the war program in 1940 through 1942, requirements estimates were repeatedly lifted to new high levels, and plans for increasing capacity had to be constantly revised. In 1943, basic metal supply caught up with and exceeded requirements, and by 1944, the surplus of primary production was large enough to force reduction in output and plant closings. In the past two years, ingot capacity has been ample, though periodic critical shortages have been experienced for a few fabricated shapes as a result of sudden shifts in demand. And now with all controls lifted we are faced with surplus capacity, surplus stocks, and surplus scrap. In 1938 the Aluminum Co. of America was the only U. S. producer of primary

Jan 1, 1946

By Joseph Pogue

THE, prices of crude petroleum and its derivatives have shown an upward trend from 1915 to 1920, and a downward trend from 1920 to 1923, see Table 1. Over the former period, oil prices were dominated by the rapidly increasing demands and inflation incident to the war and its aftermath, while over the latter period oil prices were influenced at the outset by deflation and then by the conditions of overproduction that have characterized the past three years. The purpose of this paper is to analyze the broader features of the more recent price movements in the petroleum industry and to relate these features to basic economic conditions in the industry. INDEX NUMBERS OF OIL PRICES The analysis and comparison of price movements may be facilitated by converting actual prices into relative prices, or index numbers, with 1913 taken as a base of 100. In this way, the various price groups are expressed as percentages of the 1913 prices and may thus be readily compared with one another or with the average prices of other commodities similarly expressed. Table 1 gives the index numbers representing the average prices of crude petroleum, gasoline, kerosene, fuel oil, lubricating oils, and all commodities. The last named is the index of all commodities as published by the U. S. Bureau of Labor Statistics and .is widely accepted .as the official measure of the general price level. The index numbers of oil prices were calculated by the writer from weekly quotations published in trade journals.

Jan 3, 1924

The fundamentals of blasting involve both the properties of explosives and of the rock being blasted. Four of the most important explosive properties appear to be energy density, bulk density, rate of energy release and the pressure- time history of the gases produced. Important rock properties are density and porosity, strength, and energy absorption including the effective moduli of elasticity. Rock structure also has a marked effect on its properties: for example, joints, bedding, and fracture alteration. Several mechanisms enter into rock fragmentation by blasting. These include slabbing, radial fracturing, crushing and bursting by the gas bubble. All of these factors are closely related to properties of both explosives and rock. Slabbing depends upon the first generated stress wave, whose shape and magnitude are a result of the pressure generated by the explosive, its time history and the resultant response of the rock, including its ability to sustain the stress wave. Actual slabbing, in turn, is a function of the magnitude and shape of the pressure pulse and the tensile strength of rock. Further fragmentation depends to a great extent upon the amount of gas in the bubble and its energy and pressure.

Jan 10, 1967

By Richard E. Chism

The metric system is now in official use in the Republic of Mexico, having been adopted by the Government in the year 1862. Athough it is used to compute all customs and other duties to be paid to the General Government, in the measurement of public and private lands arid in all freight and other transactions on the railroads, and is taught exclusively in the public schools, the system has made but slight head way among the people,and has not succeeded in displacing the old-time weights and measures, which are still used in ordinary commerce. The latter were founded on old Spanish models, but, owing to the inexactness of the first standards and to subsequent changes, differ at present very widely from their originals. As to local modifications, weights are the same all over the Republic, but measures of the same name differ greatly in capacity in different States, and even in neighboring towns. The value in the metric system here assigned to each denomination of the old weights and measures is that fixed by the Mexican Government at the time of the adoption of the metric system. The equivalents in American weights and measures were calculated by me from data found in Trautwine's Pocket-Book as to the comparison between the French and American weights and measures, and are believed to be correct. I shall be thankful for early notice of any error that may be detected, that it may be corrected before the final publication of this paper in the Transactions. Linear Measures. Kilometers. Miles. 1 legua (league) = 5000 varas . = 4.19 2.604375 Meters. Feet. 1 vara (yard) = 3 pies.....= 0.83800 2.749578 1 pie (foot) = 12 pulgadas.....=0.27933 0.916526 Inches. 1 pulgada (inch) = 12 lineas . = 0.02328 0.916526 1 linea (line).......= 0.00194 0.076577 The vara is also divided (for dry-goods-selling) into palms or cuartas (palms or quarters). Meters. Feet. Inches. 1 palmo or cuarta .. .. = 0.209500 =0.687394 = 8.248728

Jan 1, 1887

Cortez Gold Mines operated a conventional 2,100 mtpd (2, 300 stpd) cyanidation plant until the 5 million ton ore body was worked out in 1973. (See Gold and Silver Cyanidation Plant Practice by F. W. McQuiston, Jr. and R. S. Shoemaker, Society of Mining Engineers, AIME 1975.) Sub-grade material was dump leached at the mine -mill location in 1971, and the resulting pregnant solutions were added to the feed in the plant's Merrill-Crowe precipitation unit for gold recovery. In early 1973, however, Cortez put into operation their Gold Acres mine which was located about 13 krn (8 miles) to the west of the 'Cortez mine. Economics at that time dictated the heap leaching of the lower grade portion of the ore body with the higher grade being trucked to the Cortez plant for milling. Leach ore was moved directly from the open pits to prepared leach pads located on a gently sloping terrain of 570 grade. Preliminary pad preparation at the leach site included removal of vegetation which was composed of sagebrush and grading of the base. Pads were comprised of mostly minus 74 micron (200 mesh) materials and were made of clay-silt or slime tailings spread on the pad area in thin 50 to 75 mm (2 to 3 in. ) layers, compacted with a vibrating roller compactor to a depth of about 380 mm (15 in.). This was followed with a 100 mrn (4 in.) layer of coarse rock to prevent erosion on the pad and to allow solutions to move laterally under the heaps. Leach solutions normally traveled the length of the heaps and were collected in plastic-lined ditches from which they flowed by gravity to the pregnant solution storage pond. Both pregnant and barren ponds were constructed in the same manner as the leach pads - being lined with compacted tailings or clay silts. The Gold Acres facility required pregnant solution storage of 6 million liters (1.6 million gal) and barren storage of 3.8 million liters (1.0 million gal) designed to handle two to three days of heap drainage or to retain run-off from a major rainfall. Various heap heights were tried including 3, 6, and 9 meters (10, 20, and 30 ft), with a 6 m (20 ft) height selected. Ore was dumped by trucks in a single 6 m (20 ft) lift using a D8 Caterpillar dozer for

Jan 1, 1981

Erwin S. SperRy, Bridgeport, Conn.: The analysis of refined copper is a subject of great importance, and has not received the attention it deserves. Copper metallurgists, therefore, will welcome the paper of Mr. Heath with satisfaction. The state of the art of the chemical analysis of copper has been such that consumers, if they could not afford to run any risk, have been obliged to buy copper from the smelter having the best reputation, and a specification for copper to meet certain requirements could not be drawn up by the mere giving of the chemical constituents. Mr. Heath has brought the analysis of the copper to such a state that when a specification calls for copper " equal to Lake copper " one will know immediately what percentage of the pure metal to expect. It seems to be a pretty well established fact that the copper of Lake Superior is practically free from antimony and bitmuth ; and, with the exception of arsenic, the other elements are easily separated from copper by electro-deposition in an acid solution. The authorities differ in regard to the question whether antimony is deposited with the copper in an acid solution. Classen* recommends the employment of a solution containing 10 per cent. of free nitric acid, sp.gr.1.21, and the strength of the current from 0.3 to 0.4 ampere, in order to prevent the other metals from being deposited with the copper; and for this reason, I presume, the method has been generally used. I, myself, have been accustomed to use such a solution for the analysis of copper-alloys, but have found that for such alloys only a small quantity of nitric acid is necessary, if sulphuric acid is present in sufficient amount to give the solution the required conductivity.

Jan 1, 1898

At its meeting on February 21, 1933, the Board of Directors passed the following resolution defining and expressing the policy of the Institute with respect to official participation or action in controversial matters: WHEREAS, the Board of Directors at its last meeting passed the following resolution : "The Board of Directors, having been appealed to by several Local Sections for advice concerning the attitude and policy of the Institute relating to the endorsement of candidates for public office, the following statement of policy is formulated: "Whereas, the American Institute of Miming and Metallurgical Engineers is organized for purely professional and scientific purposes, and whereas diversity of opinion among its members on partisan or political questions is inevitable, it is the ex- pressed policy of the Institute to refrain from official participation or action in political and semi-political matters."

Jan 1, 1946

By K. H. Heino

Two 200 T/da Lurgi Turbulent Layer fluid-bed roasters have been in operation at Canadian Electrolytic Zinc Limited since 1966. Zinc concentrate containing 52-54% Zn, 9-11% Fe,31-33% S is treated to produce calcine containing 60-62% Zn,10-12% Fe, .l-.3% S as sulphide and .8-1.2% S as sulphate. Each roaster train comprises a waste heat boiler, two cyclones in parallel and a two-field electrostatic precipitator. Distribution of calcine collected is 10-15 percent from bed overflow, 55-65 percent from boilers, 20-25 percent from cyclones and 2-6 percent from precipitators. A Monsanto designed contact plant produces acid at a rated capacity of 365 T/da (100% H2304 basis) from roaster gases diluted to 7.0-7.5% S02. The process steps are gas cleaning and cooling by weak acid scrubbing, acid mist removal in electrostatic precipitators, gas drying in 93.5-96.5% H2304, conversion of sulphur dioxide to sulphur trioxide in a four-pass converter containing vanadium pentoxide catalyst, and absorption of the sulphur trioxide in 98.1-98.3% H2S04. Product acid is 93.2% H2S04. Conversion efficiency is 97-98 percent and overall sulphur recovery from concentrate is 87-90 percent. The adjacent fertilizer plant has a capacity of 135 T/da of P205. The products are 54 percent phosphoric acid, run-of-pile triple superphosphate, and diammonium phosphate. The plant is of Ugine-Kuhlman design and consists of an air-cooled multiple tank reactor, a tilting pan filter, and a forced circultation vacuum evaporator. Triple superphosphate is made on a continuous belt and partially cured in a rotary dryer. Diammonium phosphate is produced by ammoniating phosphoric acid in a single stage reactor. The slurry of ammonium phosphate is granulated in a blunger and dried.

Jan 1, 1970

By Leo Greenberg

As one of its functions, the U.S. Bureau of Mines gathers and analyzes mine accident data, and then publishes annual reports on work injury experience in the various segments of the minerals industry- coal, nonmetals, rock. These reports contain a wealth of detailed data, with a multitude of analyses and cross-tabulations, all intended to shed as much light as possible on accidents and to suggest possible ways of reducing them. In this article, the terms, "injury" and "accident" will at times be used interchangeably to denote accidents which cause disabling injury. The Bureau bases many of its analyses on American National Standard Z16.1 for recording and measuring work injury data. This document establishes two models for measuring disabling injury experience: (1) the frequency rate, obtained by dividing the number of man hours into the number of injuries multiplied by 1 million, and (2) the severity rate, similarly constructed, with the variable of interest being the number of days lost due to these injuries. Similar computations are performed by the U.S. Bureau of Labor Statistics and the National Safety Council. Additionally, these models are used in many other countries, sometimes with minor changes.

Jan 1, 1971

By Franklin Allison

THE influence of cobalt and nickel on the properties of steel might be readily expected to be very similar. The two elements occupy close and somewhat unusual positions in the periodic table, their chemical behavior and compounds are so completely analogous and their various physical properties, including the ferro-magnetic characteristic, show such a remarkable correspondence, that there is no doubt of a strong resemblance existing between these two metals. However, the variety of, properties that are obtained from steel is due, largely to the fact that the element iron possesses allotropic forms. Alloying elements that affect these allotropic forms, or alter the nature of the allotropic changes, exert a profound influence on the resulting steel. In the case of nickel and cobalt, although these elements are very similar chemically and physically, it is found that they differ distinctly in their individual effects on the critical points of iron. Both nickel and cobalt form a series of homogeneous solid solutions with iron at temperatures above 1800° F. The difference in their behavior does not occur until changes begin to take place in the solid state below this temperature. An inspection of the respective thermal equilibrium diagrams at the lower temperatures makes the opposite effects of nickel and cobalt clearly evident.

Jan 3, 1927

By Wittenau, E.

OPERATION of a pilot mill of 100 tons' daily capacity during 1930 and 1931 proved that the copper minerals of the Colorado and Clay sections of the Morenci ore body could be successfully concentrated by the flotation process. Economic conditions caused postponement of further testing work until late in 1938 when the former No. 6 Concentrator at Morenci was converted into an experimental mill of 1500 tons' daily capacity which was known as the Test Concentrator. The Test Concentrator began continuous operation on April 3. 1939, using such crushing and grinding equipment of the No. 6 Concentrator as was appropriate. Modern classifiers and certain flotation machines were installed and later other types of flotation machines, a large grate-type grinding mill. mechanical screens, a short-head cone crusher, and a disk filter were added to the test equipment. Operation was uninterrupted until Dec. 31, 1941.

Jan 1, 1942

By Robert W. Hunt

When I had the honor of presenting to the Institute at the Buffalo meeting in October, 1888 (Trans., xvii., 226), my paper on " Steel Rails and Specifications for their Manufacture," I expressed my hesitancy in submitting my ideal rail-sections. Since then, continued residence in Chicago, perhaps, or greater intercourse with railroad officials, has either given me more courage or has taught me that so little is really known on the subject that one is safe in expressing one's views, let them be ever so erroneous. As a further personal excuse, I may remind you that " fools rush in," etc. At all events, I would now call attention to certain rail-sections which I believe to be good. I do not say they are the best, but I feel sure they have more merit than the majority of the adopted heavier-sectioned rails. In determining the proper form for a rail, the subject should be considered from two points; first, and most important, the duty required ; second, and of almost equal importance, the influence of existing details of manufacture upon the character of the finished product. It is perfectly proper that all the strains to which the rail will be subjected should be considered and calculated. But its ability to resist them will depend quite as much upon the character of the metal as upon the form of its section. That which would be the realization of the ideal with good steel would be disappointment with poorer metal. Therefore, the railroad engineer should always have in mind and pay due respect to what the metal worker may give him—the may being the factór of danger to be covered by his factor of safety, and possessing greater importance than any formula laid down by never so eminent authorities. It is well-known how positive is my conviction that high heat during manufacture and good rails cannot go together; hence, if we insist upon the avoidance of this evil by rail-makers, we must give them sections which can be made at low temperatures with commercial as well as technical success. The market-price for rails controls the practice of makers, and,

Jan 1, 1889

By Joseph E. Pogue

The prices of crude petroleum and its derivatives have shown an upward trend from 1915 to 1920, and a downward trend from 19'20 to 1923, see Table 1. Over the former period, oil prices were dominated by the rapidly increasing demands and inflation incident to the war and its aftermath, while over the latter period oil prices were influenced at the outset by deflation and then by the conditions of overproduction that have characterized the past three years. he purpose of this paper is to analyze the broader features of the more recent price movements in the petroleum industry and to relate these features to basic economic conditions in the industry. Index Numbers of Oil Prices The analysis and comparison of price movements may be facilitated by converting actual prices into relative prices, or index numbers, with 1913 taken as a base of 100. In this way, the various price groups are expressed as percentages of the 1913 prices and may thus be readily compared with one another or with the average prices of other commodities similarly expressed. Table 1 gives the index numbers representing the average prices of crude petroleum, gasoline, kerosene, fuel oil, lubricating oils, and all commodities. The last named is the index of all commodities as published by the U. S. Bureau of Labor Statistics and is widely accepted as the official measure of the general price level. The index numbers of oil prices were calculated by the writer from weekly quotations published in trade journals. Fig. 1 shows in graphic form the trend of oil prices by months over the period 1920-23. It may be observed that the prices of crude oil and its derivatives move in rough conformity with one another; tend to follow

Jan 1, 1924

By BARONJUPTNER VON JONSTORFF, Andrew A. Blair, GUNNAR DILLNER

IT is a well-known fact that the results of different analysts, when operating on the same identical sample of steel or iron, are far from concordant, and it not infrequently happens that great annoyance and trouble in the commercial community are occasioned by these discrepancies. Attempts have been made at various times to investigate the causes of such differences and to obtain more reliable methods of analysis. The most important of these was made by the British Association in 1889: The following gentlemen, with Sir W. Roberts-Austen as Chairman, and Professor T. Turner as Secretary, were constituted as a committee to investigate the question, viz.: Sir F. A. Abel, Mr. Edward Riley, Mr. G. J. Snelus, Mr. John Spiller, Professor J. W. Langley, and Professor Tilden. Average .samples of steel were prepared in America under the superintendence of Professor J. W. Langley. The steels, in the form of turnings, were divided and distributed to sub-committees in Great Britain, America, France, Germany, and Sweden. In Sweden Professor Åkerman acted as Secretary to the Swedish committee. The Government Department of Tests was appointed in Germany; Mr. Ferd. Gautier in France; the British Association Committee in England; Messrs. William

Mar 1, 1905

THE LIFE and works of Alexander Agassiz, first president of the Calumet & Hecla Mining Co., were recalled to memory when a monument bearing his statue was unveiled in Agassiz Park, at Calumet, Mich., on Sept. 26, The statue is the work of Paul W. Bartlett, of New York, and was erected by George R. Agassiz, eldest son of Alexander Agassiz. We are indebted to Rodolphe L. Agassiz, now president of the Calumet & Hecla Consolidated, for the accompanying photograph of the statue. The principal address at the unveiling ceremony was delivered by Allen F. Rees, of Houghton, who said, in part: To the world at large Alexander Agassiz was preeminently the man of science. With all his devotion to the industrial life of this district, he found the time to devote to the con-tinuation of his work of scientific research which had been the life work of his fa-ther, Louis Agassiz. Not only did he acquire eminence for his scientific at-tainments and learn-ing, but he was recognized and hon-ored throughout the civilized world for his achievements and accomplishments in the realm of original research. His work in the fields of nat-ural science, in oceanography, in marine zoology, and in other similar lines of research, has added much to our knowledge of the world's mysteries. His life was one of accomplishment also in the industrial world. The union in one life of acknowledged achievement as a scientist and the accomplishment of great results in the prac-tical industrial world is a rare thing, and its possibility has never been exemplified in greater measure than in his life and its results.

Jan 11, 1923