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By Dr. George W. Annadale, Dr. Adrian G. Chantler

Materials which are likely to produce Acid Rock Drainage (ARV) can be identified with a reasonable degree of certainty. However, it is not currently possible to predict the concentrations of future contaminant discharges with similar confidence. One way of overcoming this problem is to model the uncertainty in knowledge related to estimates of future contaminant concentrations, and utilize this information in a decision model to decide on acceptable levels of expenditure on ARV control measures. The paper presents a risk modeling approach and proposes a decision model.

Jan 1, 1992

By K. D. Hester, A. W. Fletcher

A nickel-copper sulphide concentrate was treated in a pilot plant at Warren Spring Laboratory during 1961, by a hydrometallurgical roast-leach-solvent extraction process devised to cleanly separate the metal values and produce acid sulphate liquors containing the metals. It is shown that 86 pct of the nickel and 95 pct of the copper could be leached from the calcine, after a sulphatizing roast on finely ground flotation concentrate. Iron was removed from the leach liquor by limestone neutralization with a small loss of values. Copper and nickel were separated by solvent extraction with naphthenic acid in kerosene after partial neutralization of the iron-free liquors with ammonium hydroxide. Hydrogen sulphide and chlorine were used to remove zinc (and residual copper) and cobalt impurities respectively. The recovery of pure copper and pure nickel, by electrowinning, from the acidic solvent extract strip liquors finally produced, appears technically feasible. An economic analysis of production costs shows that small, geographically isolated, nickel-copper sulphide deposits cannot usually be worked profitably by established processes. The requirements for profitable operation on a comparatively small scale could possibly be met by a flotation-roast-leach process. Two difficulties, obtaining satisfactory extraction of nickel from a sulphide concentrate and separating the copper and nickel in solution, have prevented the previous use of this method. A solution to the first problem, dissolution of the nickel, was described in a recent paper by Thornhill.1 It was shown in this paper that copper and nickel in a flotation concentrate could be oxidized to water soluble sulphates by roasting in a fluidized bed with added salt cake. Workers at the Warren Spring Laboratory have shown that the separation of copper and nickel can be accomplished by solvent extraction using a relatively inexpensive carboxylic acid, naphthenic acid. Moreover, the mineral acid required to strip values from the loaded solvent could be produced, and the metals recovered, by electrowinning; thus the latter section of the process was regenerative. The removal of iron from the leach liquor and the elimination of impurities such as zinc and cobalt before nickel electrowinning would be necessary to complete the flowsheet. The process under investigation could therefore be summarized (Fig. 1) as follows: 1) Flotation to produce a bulk sulphide concentrate. 2) Fluidized bed roasting to sulphate the nickel and copper minerals. 3) Leaching of roaster calcine to extract soluble nickel and copper. 4) Precipitation of iron from the separated leach liquor by air oxidation after the adjustment of pH and temperature. 5) Recovery of copper from the iron-free Liquor by pH adjustment and liquid-liquid extraction. 6) Purification of the copper raffinate by removing zinc and residual copper as insoluble sulphides and cobalt as cobaltic hydroxide. 7) Recovery of nickel from the purified liquor by pH adjustment and liquid-liquid extraction. Laboratory and pilot plant studies detailed below, were carried out at the Warren Spring Laboratory, to test the feasibility of each one of the unit processes and to obtain preliminary plant design data. FLOTATION The ore was an altered basic rock containing concentrations of magmatic sulphides.

Jan 1, 1964

Ocean engineers and technologists will assemble in Houston, Texas, during May 3-6, 1976, for the Eighth Offshore Technology Conference (OTC) . More than 50,000 members of industry, government, and academia from 94 nations will participate in what is generally acknowledged as the offshore industry's show-of-shows. A well-diversified 280-paper technical program has been divided into 42 general sessions that range from seafloor surveying and offshore mining to navigation systems and environmental issues. In addition, the largest technical- educational exhibition in the conference's eight-year history will augment the OTC '76 program.

Jan 4, 1976

Jan 1, 1944

By William E. Ford, Edward Salisbury Dana

430. The more important of the special properties of a mineral species with respect to heat include the following: Fusibility; conductivity and expansion, especially in their relation to crystalline structure; change in optical characters with change of temperature; specific heat; also diathermancy, or the power of transmitting heat radiation. The full discussion of these and other related subjects lies outside of the range of the present text-book. A few brief remarks are made upon them, and beyond these reference must be made to text-books on Physics ant1 to special memoirs, some of which are mentioned in the literature (p. 305).

Jan 1, 1922

By Sergio Neves Monteiro

This work had as its objective the characterization of a waste material, steel slag, generated from an integrated steel plant, with a view to its recycling and incorporation into red ceramics fabrication. The characterization was performed in terms of chemical composition by X-ray fluorescence (XRF), particles size distribution, X-ray diffraction (XRD), thermal analysis (DTA/TG) and scanning electron microscopy (SEM). The results indicate that the steel slag presents high amount of Ca, Fe, Mg and Si. The weight loss of the steel slag at temperatures above 800oC is associated with calcium carbonate decomposition. The coarse particle size of the steel slag is inadequate for its direct recycling into red ceramic fabrication. It is necessary to screen or to grind the waste. As a possible solution, it is suggested that screening or grinding the steel slag to a convenient particle size distribution would allow its successful industrial incorporation into red ceramics products.

Jan 1, 2006

By R. I. Jaffee, J. G. Dunleavy, W. Hodge, H. R. Ogden

Early in 1946, at the instigation of the U. S. Army Signal Corps, the authors made an extensive survey of the available literature covering high-strength, high-conductivity alloys. For the purposes of the Signal Corps, the minimum tensile strength to be considered was 150,000 psi, together with at least 50 pct IACS conductivity. No single alloy was found to be in production, or mentioned in the literature, which had this combination of properties. The constitution diagram for the iron-copper alloys is not well established in the respect to the two-liquid region. Fig I, taken from the 1939 Ed. of the ASM Metals Handbook, shows a two-liquid system existing above the liquidus temperature, but disconnected from it. Although Ruer and Fickl and Ruer and Goerensz definitely established the fact that two liquid layers could occur in the system, Ruer3 was not convinced that the line of immiscibility was closed in the center. Maddocks and Claussen4 found no liquid immiscibility at temperatures up to 157oOC in alloys containing almost no carbon. Although the diagram would indicate age hardening of the copper-iron alloys is possible, Hanson and Fords found that little hardening effect could be obtained. However, Gordon and Cohen6 reported that the response is better if the quenching is very efficient. Although iron has a potent effect on the conductivity of copper, Hanson and Fords have shown that, when hot-rolled copper-iron alloys are aged at 1200°F, the electrical conductivity decreases sharply with iron contents up to 0.2 pct Fe, and then levels off at conductivities between 60 to 70 pct IACS with compositions to 2.1 pct Fe. They also found that aging did not increase the tensile strength, although increasing iron content gave a moderate improvement in strength. High-strength copper-iron alloys, usually containing about 60 pct iron, had been reported by Smith and Palmer.7 They found that an alloy containing 56.4 pct copper, 0.21 pct magnesium, balance iron, would give a maximum tensile strength of 170,000 psi and an electrical conductivity of slightly over 35 pct IACS. The alloy could also be processed to have I50,000 psi tensile strength, and about 41 pct I.\CS conductivity. Decreasing the iron content increased the electrical conductivity, but the long mushy range during freezing of the alloy containing 10 to 20 pct iron made the production of good castings difficult. In spite of the difficulty encountered by Smith and Palmer with alloys of around 20 pct iron, it was decided to make a rather complete investigation of this type of alloy. As a result of this investigation, a method of alloying and fabricating copper alloys containing 10 to 15 pct iron was developed

Jan 1, 1949

By G. Paillard, I. E. Puddington, A. F. Sirianni, F. W. Meadus

Experiments with some selected Nova Scotia coals and a single sample of American anthracite, reconstituted in granular form with lower sulphur and ash contents by spherical agglomeration methods, are described. The effect of different bridging liquids, grinding times, gangue depressents and modes of agitation on the final product are discussed. The application of agglomeration techniques as a means of drying wet coal fines is also noted.

Jan 1, 1968

J. A. MATHEWS, ? Syracuse, N. Y. (written discussion§).-This paper by Prof. Hoyt, together with the papers by Messrs. Jeffries, Clayton, Rawson, and Moore, submitted at this meeting, constitute a valuable symposium on what might be called the "mechanism of failures." Prof. Hoyt has not emphasized too strongly the importance of the notched-bar test, or the notch as a feature of a structural design. There has been a good deal of misunderstanding in reference to the value of the notched-bar test, and various vibratory tests such as the Wohler, White-Souther, Stanton, and Upton-Lewis have been devised. This form of testing has received more attention abroad than it has here, and has been the subject of a great many very careful investigations. I have heard many expressions of surprise at the apparent lack of agreement between the results of vibratory tests and the results of shock tests. It is not necessary that the values obviously should agree, because obviously different properties are being tested. In reference to the presence of notches or sharp corners in the construe tion of machines or parts, would say that these more frequently lead to fatigue failures than to typical notch-bar failures clue to sudden impact. I have seen a number of airplane crankshafts that had apparently failed due to a keyway that was left with fairly sharp angles at the bottom. The material satisfactorily responded to every test, including the notched-bar test, nevertheless the shafts failed, showing a fatigue break, usually spiral and sometimes making at least one complete turn around the shaft. The lack of concordance between supposedly duplicate notched-bar tests in my experience has been most often due to lack of care in the machining of the test piece itself. Prof. Hoyt draws attention to a report of Charpy in 1909, in which two steels of almost identical physical properties show very different results in the notched-bar test. He states that the microstructure at once showed that one steel was in poorer condition than the other. More recent experience has shown other cases of this kind where not even the microstructure serves to reveal any startling differences in structure.

Jan 4, 1919

This paper concerns a pragmatic approach to a problem that is common to many operations in the mining industry: how, over the short-term, to grasp the extent and distribution of long-term financial risk from environmental causes and reduce these risks strategically, in order to maintain stability and flexibility in the operations. Surprisingly, many companies operate without an environmental master plan or tools that can help managers measure and reduce financial risks. Such companies may be subject to unknown unacceptable financial risks from environmental causes. While many companies have some kind of internal system of environmental standards, it is often the case that such systems have uneven or limited effect, and offer no opportunities for visualising, measuring or managing aggregate financial risks from environmental causes. `Aggregate risks' are defined here as the calculated total expected financial costs to a company, or a subdivision of a company, from environmental causes at nominated operations over a defined time period. Aggregate risks take into account the type and magnitude of an environmental problem set, the likelihood of occurrence, and the time frame during which the problems will develop or solutions are required. For the large corporation, the 'amount of' aggregate environmental risk is a statistic that can be managed, along with other financial parameters, at the corporate level to improve the stability and predictability of operations, and protect the interests of shareholders. This paper concerns development of a management framework and a tool for the large corporation that responds to the need for managing aggregate environmental financial risks. The logical framework proposed to overcome the need for strategic vision is the Environmental Master Plan, and this is described in the next section. The analytical tool proposed to measure aggregate risks and provide relevant data and insights to managers, is called an Environmental Risk Management Information System, and its mechanics are described in a subsequent section.

Jan 1, 1994

By Brij M. Moudgil

Disposal of fine coal refuse is one of the major technical problems which could adversely affect growth and development of the coal industry. At present one of the most: common methods for disposal of fine coal refuse slurry involves impounding the slurry behind dams. However meeting new federal and state government regulations for building, maintaining and reclaiming these impoundments in addition to terrain and space considerations render this technique to be only marginally competitive with other disposal methods. The coal industry has been actively engaged in developing alternate disposal techniques which are economically feasible and environmentally acceptable. A review of coal refuse disposal problem and current refuse disposal practice both in the eastern and western coal fields is presented. Various promising techniques being developed for economical and safe disposal of fine coal refuse slurry are also discussed.

Jan 1, 1980

By L. W. Fagg

The purpose of this paper is to present in a convenient form data and examples necessary in making dynamometer card analyses; also to outline a procedure of well weighing. Many articles and papers have been written delving into the mathematical considerations relative to the shape and characteristics of dynamometer cards. However. it is recognized that there are too many unknown factors involved in such calculations to assure a workable degree of accuracy. For this reason the accepted procedure is to take dynamometer cards on wells in question rather than try to calculate the load curve. The polished rod dynamometer is now recognized as a necessary tool for measuring loads, torque, and horsepower. It is also used to determine pump action and trouble-shoot for any seemingly abnormal pumping condition. The apparently infinite variety of a = maximum load (height x scale constant) b = minimum load. Range of load is difference between maximum and minimum load speed—taken with stop watch stroke —measured at polished rod c = beginning of down stroke in direction of arrow. (End of up stroke) d = beginning of up stroke. (End of down stroke). Polished Rod Horsepower = (Area of card) x Scale const. x Stroke x Length x spm (Length of card) 33000x 12 1.35 1.35------x5300x 24 x 12 2.53 --------------------------= 2.06 23000x12 Appraximate Peak Torque: Upstroke = (2390) (12) (1) = 28,700 in. Ib Downstroke = (1 860) (12) (.866) = 19,300 in. Ib Counterbalance should be increased to make up stroke and down stroke peak torque equal. FIG. 1 dynamometer cards that can be obtained is one reason for the general lack of usage of the dynamometer as a control instrument rather than a means for making routine measurements of leads and horsepower. When it is considered that the dynamometer card is a record of the resultant of all forces acting on the polished rod at any particular instant during the pumping stroke. the problem is then one of breaking down this resultant into its various components. As a means of a quick review we shall consider the examples shown in Figs. 1 to 9: and Tables I and II and then proceed to the interpretation of variously shaped cards caused by some abnormal operating condition. In Table 11, when we were considering the factors involved in calculating the peak polished rod load, it can be seen that the factors involved greatly oversimplify the problem. Certain assumptions are made which may or may not he even close to the actual field conditions, such as the specific gravity of the fluid generally considered as one; that the crank has constant angular velocity; that the down-hole friction is zero; and that the fluid lift is from the pump. In the following examples we shall see what a variation in fluid weight and friction can do to the general shape and magnitude of the dynamometer card. (Figs. 10 to 22.) MAKING THE WELL STUDY It is obvious that it would be impractical to consider in detail all of these factors each time a well study is made, inasmuch as each well study job could conceivably be extended into a research project rather than serve the practical requirements of finding the answer to a specific problem. For this reason it is important that some objective be established previous to the time the well study is made. Load at TU = 3070 Ib Crank angle when polished rod is at position TU = ? ? = 30° Maximum counterbalance effect at polished rod = 2760 Ib Torque at TU = (Load at TU — Max. counterbalance effect-lbs) sin 0 x Length of Stroke 2 = (3070-2760) .5 x 24 = 1860 in. 15 2 Torque at TD = (Load at TD — Max. counterbalance effect-lbs) sin ? x Length of Stroke 2 = (530 - 2760) sin 330' x 24 = 13,400 in. Ib 2 Note: sin 0 from c to d on UPSTROKE will be positive value. sin 0 from c to d on DOWNSTROKE will be negative value Torque at c and d is zero because 0 is zero. FIG. 2 —APPROXIMATE METHOD FOR CALCUlATlNG TORQUE

Jan 1, 1950

By James W. Lower

IN developing the orebody on lower levels of the Star mine at Burke, Idaho, Hecla Mining Co. is faced with a serious problem in driving raises. Levels are at 200-ft intervals. As a raise is being driven between levels, at points about 70 and 130 ft from the sill, heavy pressure arches develop and the raise becomes extremely hazardous. Eventually, following a blast, caving occurs, making it impossible to recover the raise. In February 1957 it was decided to attempt sinking a small winze on the vein from the 5500 to the 5700 level. This shaft (winze-raise No. 2) was to be used as a raise prior to stoping. It was assumed, and correctly, that the heavy ground pressure could be controlled by timbering close to the bottom after each advance.

Jan 7, 1958

By Fernando Llosa

El presente trabajo describe el origen y la geología del proyecto Trapiche, como propiedad de la Cía. El Molle Verde SAC subsidiaria. Dicho proyecto está ubicado 100 km al sur de la ciudad de Abancay, región de Apurímac, parte central del sur Perú y fue descubierto por Cedimin, producto de un intenso programa de grassroot realizado a partir del año 1995 hasta el 2001 en que fue perforado. Luego fue explorado por Cía. de Minas Buenaventura a partir del 2,005 hasta la actualidad. El yacimiento es del tipo pórfido de cobre y molibdeno, su localización metalogenética es en el borde oeste del batolito Andahuaylas – Yauri, de composición calco-alcalina con presencia de pórfidos activos, que están intruyendo sedimentos clásticos – carbonatados del Jurásico – Cretáceo. En dicho "belt" se emplazan importantes yacimientos tipo pórfido y skarn de cobre y molibdeno y oro como los Chancas, Cotabambas, Las Bambas, etc.

Sep 21, 2013

By Michele L. Kimble

A fast-flow reactor mass spectrometer has been utilized to investigate the reactions of gas-phase gold cluster anions with CO and oxygen. Addition of CO to Aun - produces species of the form Au(CO)m -, where m = 2-5. However, CO does not bind to Au2 - or Au3 -. With oxygen addition in the cluster source, gold oxide species with both molecular and atomized oxygen are produced. The addition of carbon monoxide to these preoxidized gold cluster anions reveals that select species with 1, 2, and 3 gold atoms participate in the oxidation reaction to produce CO2. Bimolecular rate constants for the reactions between these species and CO are also discussed.

Oct 1, 2003

By James A. McGrath

"The predominant key word associated with all commercial blasting methods is “safety”. Safetyshould take precedent over all other aspects of the entire explosives industry which on a wholehas had an excellent track record as to number of injuries per unit of hours worked at all blastsites throughout our country."

Jan 1, 1999

By A. J. M. Ross, R. G. Wayland

The Homestake mine is situated in Whitewood mining district, in the northern Black Hills of South Dakota, in the city of Lead, Lawrence County. The entire property, comprising 557 lode claims with a total area of 3343 acres, is held under United States Patent. The older claims were 300 by 1500 ft. under local regulations, the newer ones 600 by 1500 ft. The Homestake was discovered April 9, 1876, by Moses and Fred Manuel, and Jake Harney, who were drawn into the northern hills, from the Custer placer district, by news of the discovery of rich placer deposits in Deadwood Gulch. They located a number of additional lode claims and, in a short time, the whole country was covered with locations. The Manuel brothers built an arrastre the following winter and took out $5000. The next year the Homestake lode was sold to Senator George Hearst and associates, who organized the Homestake Mining Co. Other companies were formed to exploit other groups of claims and at one time fivc companies were operating on this deposit, the Father DeSmet, the Dead-wood-Terra, the Caledonia, the Highland, and the Homestake Mining Co. These companies, however, have been merged into the Homestake Mining Company. The first stamp mill, known as the "Eighty Mill," commenced operation on July 12, 1878, and production has been nearly continuous since that time. Geology The orebodies of the Homestake are found in an intensely folded and altered bed of dolomitic limestone occurring in a series of ancient rocks believed to be of Archean age, belonging to the Keewatin series. The Keewatin series is estimated to be 20,000 ft. thick and is made up essentially of quartz mica schists, garnet schists, quartzites, slates, and some green schists, probably derived from basic igneous rocks. The dolomitic limestone bed has a thickness of 40 to 60 ft. The great width of ore, as much as 400 ft. in some of the stopes, is due to the folding, wherein the bed is repeated. In other cases the bed is stretched and pinched out. Dikes of Tertiary rhyolite cut across the country and, in places, sills overlie the

Jan 1, 1925

Council PRESIDENT OF THE COUNCIL. JOHN HAYS HAMMOND NEW YORK, N. Y. (Term expires February, 1908 ) VICE-PRESIDENTS OF THE COUNCIL. HENRY M. HOWE NEW YORK, N. Y. J. B. GRANT DENVER, COLO. JAMES D. HAGUE NEW YORK, N. Y. (Term expires February, 1908.) SAMUEL B. CHRISTY BERKELEY, CAL. JOHN A. CHURCH NEW YORK, N. Y. PERSIFOR FRAZER PHILADELPHIA, PA. (Term expires February, 1909 )

Jan 1, 1910

By D. O. Shah, K. C. Adiga

Flotation of coal after multistage addition of frother was found to yield coal fractions with significantly lower ash content as compared to the feed. Ignition and combustion characteristics of different coal fractions were evaluated using a differential thermal analyzer (DTA). A correlation between low ash content, low specific gravity, and high reactivity of coal was observed. It is suggested that in the ignition stage, removal of mineral matter enhances reactivity through the physical changes brought about by ash removal. A detailed analysis of pre-ignition kinetics indicated the possible effect of bulk density of coal in terms of resistance to volatile release and effective (available) surface area of coal. In the char combustion stage, mineral matter seems to influence reactivity through catalytic activity of surface concentrations of metal ions, ratio of combustible/non- combustible material, internal pore structure, and surface roughness.

Jan 1, 1988

By F. G. Crack

This paper is based on the philosophy that the management structure and strategy required for mine construction and development projects are different from that required for routine production and maintenance operations in a mine. The purpose of this paper is to present an integrated approach to the management of mine development projects. This paper highlights the four major aspects of the integrated approach. First, a brief review of the various types of contract documents is provided. Second, the management organization of a project is discussed. Third, the project manager's role and the field supervisor's responsibility are briefly outlined. Finally, the use of scientific techniques for planning, scheduling, executing, and controlling projects is presented. Each of these aspects is important; however, each by itself cannot be expected to bring order or unifying impact to the complexities involved in overall project management. When all these aspects are coordinated, the result will be a sore successful project from conception to completion.

Jan 1, 1982