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By Theodore H. Eyde

The porphyry-copper province of southwestern United States and northern Mexico constitutes the largest copper-producing region in the world. More than 20 deposits discovered since World War II are being exploited or in the process of exploration and development. Because of the remarkable success in discovering new deposits, exploration activity continues at a very high rate and deeper targets are explored each year. Exploration programs for deeply buried porphyry-copper deposits require a reevaluation of the conventional exploration techniques. Though surface induced-polarization techniques have about reached their practical detection limit, aeromagnetics will play an increasing role in the exploration activity as will downhole logging tools. In addition to a valid geological concept, any successful exploration program for porphyry-copper deposits in the southwest must have two other essential ingredients: money and guts. Unfortunately many exploration programs in the southwest are underfunded and doomed to failure. Future exploration will demand more joint venturing in which larger and more expensive exploration programs can be successfully funded by groups of companies or syndicates.

Jan 1, 1975

By K. H. Nimerick, B. E. Scott, F. J. Beafore

A unique freeze conditioning agent (FCA) which functions by forming structurally weak ice rather than suppressing the freezing point of water has been successful in alleviating frozen coal problems. Frozen coal treated with FCA has been quickly unloaded at temperatures below -17.8OC (O°F). Other applications of FCA include deicing: conveyor belts, idler, idler arms, and other moving parts that have been impeded by ice.

Jan 1, 1980

By Erwin S. Sperry

Brass or bronze chips, grindings, buftings, washings, and miscellaneous scrap metal sooner or later find their way into the hands of the so-called metal-smelter or " refiner," whose refining or smelting operation consists simply in melting the material, adding the requisite amounts of other metals, and then casting it in the form of ingots, which are afterwards sold

Jan 1, 1899

By Rollyn P. Jacobson

The town of Pacific, in Jefferson County, Mo., is 27 miles west of St. Louis. Since the area lies entirely on the flood plain of a cut-off meander of the Meramac River, it was considered a likely environment for accumulation of commercial quantities of sand and gravel. Excellent transportation facilities are afforded by two major railways to St. Louis, and ample water supply for washing and separation is assured by the proximity of the river. As a large washing and separation plant was planned, the property was evaluated in detail to justify the high initial expenditure. An intensive testing program using both geophysical and drilling methods was designed and carried out. The prospect was surveyed topographically and a 200-ft grid staked on which electrical resistivity depth profiles were observed at 130 points. The Wenner 4-electrode configuration and earth resistivity apparatus* were used. In all but a few cases, the electrode spacing, A, was increased in increments of 1% ft to a spread of 30 ft and in increments of 3 ft thereafter.

Jan 2, 1955

By J. H. Bramwell

THE following experience in rebuilding a furnace crucible while in blast may not be wholly uninteresting to some, notwithstanding its purely practical character. Few are aware of the frequent calls made on a furnace manager's skill and ingenuity, to meet the irregularities which present themselves with kaleidoscopic variations in the operations of furnaces. Unfortunately the methods pursued in overcoming these practical difficulties are too seldom recorded, and much valuable information is lost that could not fail to be of value to many, and to none more so than the educated technical manager, with a limited practical experience, who, without a literature or record of any kind to refer to, finds himself, in times of emergency, dependent and looking for assistance from those whom it is his province to instruct and direct. With positive data, however, that like difficulties have been successfully overcome, he can confidently resort to similar expedients, with such modifications as the circumstances may demand in his particular case, and pull through seeming impossibilities in the face of ignorant prejudice. The Quinnimont Furnace (60 x 15 feet) had been in operation but two months, when it became necessary to draw the tuyeres out a distance of 18 inches, in order to give them a resting-place; the brickwork under them being completely cut away, so that after each

Jan 1, 1877

By F. H. McDowell

For more than two hundred years Mexico has been enriching the world from her inexhaustible wealth of precious metals. From this source alone, over three thousand five hundred millions of dollars have been poured into the coffers of Europe and America. During these centuries the wants of the country in manufactured goods have been supplied from the mills and machine-shop of the Old World. English, French and German merchants in Mexico have vied with each other in their efforts to control the importing of these goods from their respective countries. The overthrow of Maximilian, the departure of the French and the restoration of the Republic, largely influenced by the strong stand taken by the United States Government during our own civil war, established a new order of things. Americans were encouraged to visit the sister republic, examine into the needs of the country, as well as its resources, and interest themselves in the work of development. More recently, under Presidents Diaz and Gonzales, liberal inducements have been extended to American capitalists to build railroads, open mines, erect reduction-works, raise cattle and improve the crude systems of agriculture. The Mexican Central Railway has been pushed south from the Rio Grande to the Capital, and, by its branches and connections, makes the whole mineral belt of the country accessible.

Jan 1, 1885

By V. Miller

Highly variable milling procedures within a geologically complex porphyry copper deposit owned by Kennecott Corp. in Nevada made it necessary to estimate copper recovery and concentrate grade in areas where actual test data was lacking. Estimation was made by first determining the relationships between desired metallurgical properties and the ore's petrology-copper mineral type, rock type, and copper grade. This relationship was then combined with previously estimated rock type, mineral type, and copper grade data in the mineral block model to predict milling properties.

Jan 1, 1985

By Leland O. Erdahi

Many problems have surfaced in our economy during this decade, and the mining industry has certainly had its share: huge capital outlays for environmental controls, volatile markets, double-digit inflation, inadequate capital markets, political uncertainties-plus shortages of energy, manpower, supplies, and equipment. All these and other problems have left their visible marks on the economy of our industry. Solutions are slow in coming; perhaps, in some instances, there are no right answers. However, it appears that many companies are using joint ventures to an increasing extent in efforts to reach partial solutions to some of these problems. A joint venture does present an economic alternative that should be examined-especially when trying to answer questions arising within the current economic context. The dictionary defines "venture" as an undertaking involving chance, risk, or danger. The word was originally applied to hazardous undertakings involving delivery of cargoes to distant ports and subsequent disposition of the merchandise, but it is now applied to any project of limited scope and temporary duration. When two or more entities join in such a project, it becomes a joint venture, and this is the context in which I have used the term. Joint ventures may be formed for exploration, for development of a new ore body, or for expansion of an existing operation. Each requires different approaches for negotiating and drafting the agreement governing the conduct of the joint venture.

Jan 9, 1975

By H. Sherman

The general curtailment of activities, so marked in 1931, was continued and intensified in 1932 and although production was maintained at approximately the level of the previous year, 1932 was chiefly characterized by the virtual cessation of drilling in many of the proven fields, a further decline in wildcatting activities, particularly in the Maracaibo Basin, and the relinquishment of large blocks of unfavorably located acreage. A total of only 60 wells was completed during the year of which six were wildcats, while at the same time concessions aggregating approximately. 3,222,000 acres were renounced and reverted to the National Government. The maintenance of production at the previously established level was made possible through the large potential built up by drilling in previous years and by a gradual increase in pumping and gas-lift installations. Towards the end of the year there was a slight but perceptible tendency towards increased drilling in certain of the proven fields. Total production for the year came to 118,076,000 as compared to 118,418,000 bbl. for 1931, while exports amounted to 114,758,000 as against 116,683,000 bbl. in 1931. Table 1 shows production and exports and the average rate per day for the first half of 1932 as compared to the second half. Table 1.—Petroleum Production and Exports in 1932, Venezuela (Barrels of 42 Gallons) Production Rate per Day Export Rate per Day I January-June............ 61,943,000 1 390, 347 July-December.......... 56,133,000 305,071 50,788,000 276,022 Total.........,....... 118,076,000 322,612 114,758,000 313,546 During 1932 the number of active vessels comprising the Lake Maracaibo fleet of shallow-draft tankers was still further reduced, some being temporarily laid up and some transferred to service in other coun-

Jan 1, 1933

By L. C. Weiner

THIS study was undertaken to round out an investigation on the effects of solid environments on the brittle fracture of zinc single crystals.' In the previous work it was demonstrated that the presence of a surface film increased the cleavage strength of crystals whose basal planes were oriented almost parallel to the tensile axis by some 43 pct. This increase was observed to be independent of the type of surface-coating material, as well as of thickness of film above a certain small critical value (about 200 to 300A). These observations were described sat- isfactorily by a dislocation-pile-up-at-a-barrier model of brittle fracture2 in which twins modifying the dislocation path act as barriers, their increase in number and homogeneity of distribution brought about by the presence of the surface film. From previous work reported on the strength of ductile metal crystals as affected by gaseous and liquid environments,3 it may be concluded that the effects of these media are present only when the environment produces a surface film on the initially clean-surfaced crystal, or when it has a disintegrating effect on a previously existing surface layer. Similarly, it might be expected that an increase in cleavage strength of initially clean zinc crystals (xo = 3", A, - 28") will result only when the gas or liquid reacts with the crystal to produce a solid, adherent surface film. Clean-surfaced crystals,l 2 1/12 in. in length, were tested in tension at room temperature in an Instron

Jan 1, 1959

By George C. Toland, Ronald E. Versaw

Most existing impoundment ponds and dams leak effluent into the soil or rock upon which they are constructed. However, proposed environmental legislation will require very stringent control of the release of toxic effluents such as cyanide. More exacting investigation, design, and construction techniques than have been used in the past will be required to satisfy these new regulations. The types of field and laboratory investigations required to develop the data for the design of an impoundment system containing toxic effluent are discussed, together with the technical considerations necessary to design this system. Design topics include reservoir sealing with natural and man-made materials; embankment sealing; embankment design considering stability, surface hydrology, capacity, and downstream catchment basins; and special implications of cyanide effluents.

Jan 1, 1977

By D. W. Frommer, M. M. Fine

Early in 1957 St. Joseph Lead Co. announced discovery of three new centers of iron ore deposition in east central Missouri.1 The discovery resulted from exploratory drilling in the vicinity of a magnetic anomaly or high. A deep hole, drilled into the Pre-Cambrian porphyry to determine the cause of anomaly, penetrated a magnetite-rich deposit.2 The magnetic surveys that revealed the anomalies were begun by the Missouri Geological Survey in 1929 and were continued into the 1930's 3. At that time an area in Crawford County known as the Bourbon magnetic high was located. A second anomaly, similar in size and intensity, was discovered about six miles to the northeast in Franklin County in the vicinity of Sullivan. This area was not studied in detail until the early 1940's.

Jan 3, 1959

By M. Karfakis, K. Kim, R. V. de la Cruz

The in situ deformability of a closely jointed basalt rock mass was determined by two different methods: the NX-borehole jack method where displacements of opposing curved platens were related to applied hydraulic pressures, and the modified Goodman jack method where tangential strains on the borehole walls were related to induced tangential stresses. The modulus obtained by the modified Goodman jack method were much higher than those obtained by the NX-borehole jack method. To explain the discrepancy, the influence of fractures and test variables, such as depth, orientation, hole location, and applied pressure on the calculated modulus of the rock mass, were analyzed by factorial analysis. It was found that the orientations and measurement depths have statistically significant effects. The in situ deformability values obtained by nonlinear regression analysis were also found comparable with other measurements and empirically predicted values for the basalt rock mass.

Jan 1, 1984

By G. P. Bowman, D. F. Howard, R. K. Saxer, J. R. Myers

This study was undertaken to redetermine the phase diagram of the lead molybdate-bismuth molyb-date salt system. A portion of this diagram was originally determined by Zambonini in 1920, and more recently by Beale. Thermal analysis and X-ray methods were used to define this system. The diagram was found to be a simple eutectic type with an eutectic at 11 mol pet lead molybdate and 634OC. A maximum solid solubility of 6 mol pet was found at the lead molybdate end of the diagram. Solid solubility at the bismuth molybdate end of' the diagram appeared to be quite limited and possibly nonexistent. These results generally agree with those of Beale, but differ significantly from those of Zambonini. MOLTEN salt systems have been vigorously investigated since World War 11. Much of this work has been performed as pure research; however, consideration has recently been given to their possible use as coolants in nuclear reactors. Because of this application and other potential applications, it was decided to reinvestigate the lead molybdate-bismuth molybdate phase diagram. This diagram was originally determined by Professor F. Zambonini of the University of Turin in 1920.' In 1961, a portion of this diagram was redetermined by Beale.2 With the quality equipment and high-purity materials available today, it was expected that discrepancies between the results of this present investigation and Zambonini's work would be obtained. This investigation was conducted in two parts. First, the general shape of the phase diagram was determined by cooling-curve analysis. Next, the primary solid-solution phase at the lead molybdate end of the diagram was investigated by means of X-ray diffraction techniques. EXPERIMENTAL PROCEDURE High-purity lead molybdate, assaying 99.993 pet, and high-purity bismuth molybdate, assaying 99.989 pet, were employed during this investigation.* The results of a spectrographic analysis of the two salts are presented in Table I. Twenty-two experimental compositions were prepared for cooling-curve analysis. Compositions selected are presented in Table 11. Several randomly selected samples were analyzed chemically to check that the compositions of the prepared specimens were within the limit of

Jan 1, 1964

By David Browne

THE use of coal-dust fired reverberatory furnaces, or indeed of reverberatory furnaces of any description, was for the Canadian Copper Co. a matter of necessity, and not of choice. For 20 years smelting had been done in blast furnaces alone, and with the Herreshoff furnaces used prior to 1904 there was no trouble in treating fine ores. But little flue dust was produced, and this, following the time-honored custom, was wetted down and put back with the charge. Whether the flue dust really smelted, or whether it was worn out by being chased around in a circle, was a problem that troubled no one. With the installation of modern blast furnaces and high-pressure blowing engines, in 1904, flue dust commenced to assert itself. Evidently more dust was made than could be smelted, but so many vital problems engaged our attention at that time that this minor question was pushed to one side. In 1906, the details of blast-furnace smelting and the conversion of matte had been worked out to a satisfactory conclusion, and the ever-increasing piles of flue dust and fine ore on the stock yard demanded serious consideration. Numerous experiments in sintering, briquetting, mixing with converter slag, forming blocks of flue dust with green-ore fines and cement, and so on, were undertaken. None of these showed much promise. Our problem, was still further complicated by the question of treating converter slag. The ore was basic, the slag was not needed as a furnace flux, and it was felt that under these conditions the old method of pouring slag in molds and resmelting in the blast furnace was an unnecessary expense. If the converter slag could be settled in basic-lined reverberatory furnaces, in which at the same time flue dust and green-ore fines could be smelted, two problems might thus be solved.

Jan 1, 1915

By W. M. Courtis

In compliance with the suggestion in Mr. Emmons's paper on the Genesis of Certain Ore-Deposits (Trans. xv., 125), that facts should be accumulated for study and future compilation, I wish to put on record, before the data are lost, a section of the Animikie series of rocks and the vein-phenomena exposed by the explorations at the Duncan mine, Port Arthur, Thunder Bay, Lake Superior. This may serve as a supplement to my paper on this district (Trans. v., 473). I trust this information will not be without interest at. the present time. The recent discoveries of very rich silver-ores at Rabbit and Silver Mountains, on the same belt, have brought the district once more before the public; and a study of the facts here set forth may assist some fellow-engineer in the determination of the value of property offered for sale in this neighborhood. The vein at the Duncan mine was tested to a depth of over eight hundred feet by shaft and drifts, and to nearly a thousand feet with

Jan 1, 1887

By A. L. Holley

THE members of the society are doubtless aware that the production of American Bessemer steel works is constantly increasing ; that the same converters and machinery are doing more work every year. This enlarged output is due to various causes, chiefly the following: 1st. Better organization-better knowledge on the part of both managers and men, of the plant and the process ; of the way to economize the more exhausting labor, and of the arrangement of the details of labor and operations so that they shall not conflict; also, more pluck-a greater willingness to take risks, or, more properly, such an intimate knowledge of the nature and capacities of the refractory tory linings in various stages of disrepair, and the probable be- . havior of the fluid metal at various stages of its treatment, that the precise nature of the risk may be better known, so that the works may be crowded to their full capacity. In the early practice, after getting four or five consecutive heats in a day, the men preferred to "let well enough alone," and to devote the remaining time to preparation for another turn. Now, thirty, and sometimes forty heats are regularly made during the twenty-four hours, day after day, without the frequent occurrence and without the fear of breakdowns or "messes," as the spilling of steel charges was graphically named in Sheffield. 2d. Although no new refractory materials have been developed, improved means of preparing such as we have, and of imbedding

Jan 1, 1874

By J. L. Keats

IN THE literature on the elimination of metalloids in basic open-hearth practice, there are a great many heats recorded in which excellent data on changes in slag and metal composition during refining are given, but in almost all of these heats either temperature data or weights and analysis of charge are unrecorded and observations on the physical characteristics of the slag are almost always lacking. With these points in mind, a test heat was made in which as complete as data possible on all the factors that affect the elimination of metalloids were obtained. THE TEST HEAT The test heat was made in a standard 100 ton stationary furnace at the Lackawanna Steel Co., Lackawanna, N. Y. on January 17, 1922. The Charge-Scrap.-The scrap consisted entirely of rail-heat butts, selected from a number of heats made, the week before the test. The average analysis of the scrap was calculated from the analysis of these heats-and from the weight of scrap from each heat. Pig Iron.-Two ladles of pig iron were used in the charge and two samples were taken from each ladle as it was poured into the furnace. These four samples were composited for the average pig-iron sample.

Jan 2, 1926

By Jesse Betterton

IN the Parkes process of lead refining, after desilverization has been completed by means of zinc additions, there will remain in the lead from 0.5 to 0.6 per cent zinc. At this stage in the refining practically all impurities are reduced to refined lead specifications except zinc and antimony. All excess of copper and nearly all the arsenic goes out with the silver. Silver remaining should not exceed 0.1 oz. per ton. It thus remains only to remove zinc and antimony to produce refined lead. The older practice was to complete refining by means of oxidation processes in reverberatory furnaces. Essentially this consisted of heating the lead to 1200° to 1300° F. and allowing it to come in contact with a considerable excess of air passing through the furnace, or accom-plish the same result by blowing the lead with steam by means of pipes introduced for that purpose, at the same time allowing air to enter the furnace. Usually some procedure involving alternate oxidation and reduction with fine coal or coke was employed in order to reduce the weight of dross or skim finally removed from the furnace. This practice had many elements of weakness in that the main flow of lead, after the preceding expensive operations had been performed, and the whole refining process nearly completed, was subjected to an operation at a comparatively high temperature, which involved much lead loss if the furnaces were not on bags, and the production of 3 to 5 per cent of the weight of the lead as dross or skim, which had to be resmelted and the lead either refined or produced as antimonial lead. In addition, the operating expense of the process was a considerable item. The, process of dezincing with chlorine was developed as a substitute for the foregoing described oxidation process, and finally resulted in such advantages as nearly equal operating costs, a practical elimination of the lead loss, and the direct production of a very valuable byproduct, zinc chloride, that may be sold as such or retreated for its zinc and chlorine contents, both of which can be reused in the refining processes.

Jan 1, 1933

By Howard R. Keil

Prior to World War 11, approximately 500 tons per day, or one-third of the ore being shipped to the Golden Cycle Mill at Colorado Springs, Colo., from the Cripple Creek district, was being treated in the flotation plant. The remaining 1000 tons, along with the flotation concentrates, received the usual roasting and cyanide treatment. Since it was not possible to make a disposable tailing on the general run of Cripple Creek ores by flotation alone, it was necessary to treat the flotation tailings by cyanidation, along with the roasted ore. By this treatment, an overall economical tailing could be made. The gold ores from the cripple creek district are the highly siliceous sulphotel-lurides with approximately 3 pet total sulphides. In the lower grade ores most of the values are found in very finely disseminated pyrite. In some of the higher grade ores the tellurides, calaverite and sylvanite, can be recognized. After several years of floating cripple Creek gold ores, having a very low mineral content, it was concluded that this type of ore required a type of flotation machine that would give a rather violent aeration and agitation. This action produced a fairly deep froth column which contained not only the free mineral, principally pyrite, but also most of the middling product; this was most essential in producing a low grade tailing by flotation alone that could be discarded to waste. After investigating most of the current types of flotation machines, it was decided to convert to the Fagergren type. During World War 11, the flotation plant was modified to handle lead and zinc ores. The treatment of these ores was carried on until April 1946. At this time the flotation plant was again reconverted to handle the Cripple Creek ores. Selecting Ores for Flotation During the period of reconversion a considerable amount of experimental work was carried on in the laboratory to determine if a disposable tailing could be made by flotation alone, on certain selected Ores from the Cripple Creek district. It was found that most of the dump Ores and a few of the low grade mine ores could be treated by this method with very satisfactory results. After the preliminary test work in the laboratory, it was decided to carry on further work On a plant-size scale to see if similar results could be obtained. On April 15, 1946, a part of the plant was put into operation as a pilot plant. The various ores that had been found suitable for treatment by this method in the laboratory, were run through the pilot plant at the rate of 200 tons per day for a period of several months. Results were so encouraging that it was decided to put the plant in full-scale operation. Since that time plant capacity has been the from 500 to 1000 tons per day. This has been done not by the installation of more machinery but by (I) crush-

Jan 1, 1949