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By John C. Branner

Stratigraphic Position of the Deposits.—During the progress of the geological survey of Arkansas, in the northern part of that State, it was found that the interval between recognizable Lower Silurian rocks below and recognizable Lower Carboniferous rocks above contains no representatives, or but poor representatives, of the whole Upper Silurian and Devonian series. In some places one passes in the space of a foot from Lower Silurian rocks to the Lower Carboniferous—the Boone chert of the Arkansas survey, or the " Burlington " beds; at other places this interval is 3 or 4 feet thick, but it is generally concealed by the ready decay of the black shale—the Eureka shale—which fills it, so that for a long time it was passed over undetected. It was only after considerable work in the region lying north of the Boston mountains, and by the valuable palzeontologic work of Dr. Henry S. Williams, of Yale University, who kindly accompanied me on a trip through this part of the State, that the importance of this interval came to be recognized, and the thin beds occupying it to be critically studied. It then appeared that this interval was occupied, for the most part, either by a greenish or black shale or by a sandstone; and eventually the sandstone was found to have a maximum thickness of 40 feet on South Sylamore creek in 15 N. 11 W., Section 21. It was, therefore, called Sylamore sandstone. The shale of this interval is generally from 3 to 10 feet thick; it is a constant feature of the geology through Carroll county, and is well exposed in the streets and cuts in and about Eureka Springe, and was for this reason named the Eureka shale. Its maximum thickness is 50 feet in the northwestern part of Benton county. The relations to each other of the Sylamore sandstone and the Eureka shale I have never determined satisfactorily; for

Jan 1, 1897

By Lancaster Jones

The gravity magnitudes obtained by means of observations with the Eötvös balance in the field are necessarily resultant or total effects due to all abnormalities of mass distribution, including even the effects due to the ellipticity and rotational motion of the whole earth. Since the object of the survey is to isolate the effects which arise solely from some particular subterranean feature, and to deduce therefrom the configuration and extent of this feature, the first step is to eliminate from the observed effects all those due to "disturbing" (i. e., unwanted) features, whether above or below the surface of the ground. The disturbing features have different characteristics, according to their situation relative to the center of the balance and to the horizontal plane through the foot of the balance, or station point; this diversity was recognized by Eotvos, who divided the total effects into so-called Normal, Terrain, Topographical, Cartographical and Subterranean effects. This classification has been adhered to by most subsequent investigators, but the writer prefers to employ the term "three-dimensional," which really indicates the essential character of the class of effect known as "Subterranean," at any rate from the standpoint of the computer of effects. Before disturbing effects can be eliminated, the features must be measured up or surveyed, whether by topographical, mining, or boring methods, and then the effects of each feature calculated and subtracted from the total observed effects. After this the problem of interpreting the residual effects will itself necessitate the computation of the assumed feature, or even a series of trial features. The task of computing gravity effects is therefore of great importance. In the early work, by Eötvös himself, the computation practically ceased when the terrain and topographical effects had been calculated, but later surveys have demanded an ever-increasing extension in the technique of computation. Certainly in surveys designed to locate minerals, particularly ores, the calculations have to be extended far beyond those of Eötvös, while his methods of computing both terrain

Jan 1, 1929

By R. G. Hall

An article on the subject of electrolytic zinc no longer needs to be preceded by an apology. The production of zinc by electrolysis is past the laboratory stage and has become an economic factor of considerable importance in the total production of zinc in the United States. The various methods of procedure to be followed fa the greatest economy of manufacture are fairly well known, consequently a detailed description of any method is no longer necessary or desirable. In this paper I shall endeavor to lay down some of the governing conditions in this industry, the relation of methods to ore deposits, freight rates, and sources of power supply. Power Points Assuming for a moment that, for the present at least, the electrolytic production of zinc will be confined to Those localities having developed water power, a glance at these powers so developed in the United States, with their relation to known zinc orebodies of economic size, will not be without interest. Northwest In the Northwest we have water powers, developed and undeveloped, . in Washington and Montana. These must, of course, bear a close relation to the rapidly growing zinc production of the Coeur d'Alenes and of the Butte districts. In general, the power of the territory in question is relatively low-priced, at least as compared with the cost of developing power from coal, and the near neighborhood of large bodies of more or less complex zinc ores makes these water powers of more than usual interest. The same remarks may be applied equally to the developed water powers of the Canadian side of the line in the Northwest, where we have again commercially available complex ore deposits such as are being exploited today at and near Trail. California One of the large complex ore deposits of the far West is to be found in Shasta County in the immediate neighborhood of the territory of the

Jan 1, 1918

By W. S. Weeks

In coursing the ventilating air through a mine it is often necessary to restrict a comparatively open split in order that it may carry exactly the desired quantity of air. Such a restriction is known as a regulator, and usually takes the form of a partition with a hole in it. The quantity of air circulating is controlled by the size of the hole or orifice. For example, it is desired to force a quantity q I cu. ft, per min. through split a (Fig. 1) and the quantity q2 through split b. It requires a pressure of 2 in. water to force the desired quantity through a, and a pressure of 1 in. to force the desired amount through b. The pressure drop between points A and B must be 2 in and a pressure of 1 in. must be destroyed in split b. This is done by inserting a regulator in b, which causes the velocity to increase in the orifice and results in a change from pressure-head to velocity-head. If the air, after passing the orifice, is slowed down in a turbulent manner, all of the velocity-head does not change back into pressure-head, so a permanent loss of static pressure results. A classic formula for computing the area of an orifice to destroy a certain amount of static pressure has been handed down from early days: 0.0004Q a =2 This formula is based on the assumption that all velocity-head in the orifice is "destroyed;" that is, does not reappear again as either velocity-pressure or static pressure. The derivation of the formula is as follows: h = head lost in regulator in fect of air. v = velocity in regulator in fect per second. q = quantity circulating in cubic feet per second. Q = quantity circulating in cubic feet pcr minute. a = area of orifice in square feet.

Jan 1, 1928

By A Karrech, C Schrank, O Gaede, I Canbulat

Strain-based failure criteria have several advantages over stress-based failure criteria: they can account for elastic and inelastic strains; they utilise direct, observable effects instead of inferred effects (strain gauges versus stress estimates) and they model complete stress-strain curves, including prepeak, non-linear elasticity and post-peak strain weakening. In this study, a strain-based failure criterion derived from thermodynamic first principles utilising the concepts of continuum damage mechanics is presented. Furthermore, implementation of this failure criterion into a finite element simulation is demonstrated and applied to the stability of underground mining coal pillars.In numerical studies, pillar strength is usually expressed in terms of critical stresses or stress-based failure criteria where scaling with pillar width and height is common. Previous publications have employed the finite element method for pillar stability analysis using stress-based failure criterion, such as Mohr-Coulomb and Hoek-Brown, or stress-based scalar damage models.A novel constitutive material model, which takes into consideration anisotropy as well as elastic strain and damage as state variables, has been developed and is presented in this paper. The damage threshold and its evolution are strain-controlled, and coupling of the state variables is achieved through the damage-induced degradation of the elasticity tensor. This material model is implemented into the finite element software Abaqus and can be applied to 3D problems.Initial results show that this new material model is capable of describing the non-linear behaviour of geomaterials commonly observed before peak strength is reached as well as post-peak strain softening. Furthermore, it is demonstrated that the model can account for directional dependency of failure behaviour (ie anisotropy) and has the potential to be expanded to environmental controls such as temperature or moisture.CITATION:Gaede, O, Schrank, C, Canbulat, I and Karrech, A, 2014. A strain-based failure criterion for pillar stability analysis, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 393–398 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By Norman Paley, Zachary Pickett

The Red Dog Mine is a high-grade zinc-lead mine located in northwest Alaska which began operations in November 1989. In June 2014 the upper half of a charge in a trim shot in the Aqqaluk pit deflagrated. No other holes in the area were observed to react and the remainder of the pattern was shot without incident. This was the only known case of a deflagration in the 25 years of operations. As part of the investigation into the cause of this incident rock samples were obtained from the area of this hole and from other areas in this pit. The samples were assayed and tested for reactivity using the Reactive Ground Catalyzed Adiabatic test. Approximately half of the samples were found to be reactive with standard blasting agents. Unexpectedly, some of these were found to be reactive with blasting agents doped with urea to act as an inhibiter. Relationships between element grades and reactivity and between Specific Heating Capacity and reactivity were developed; however, the small sample size led to these models having an unrealistically large number of geological model blocks tagged as reactive. A program to better understand the behavior by testing more samples was initiated. Drill core was selected based on the predicted level of reactivity using the aforementioned relationships. The samples covered a greater range of grades and lithologies and included rock from the soon to be developed Qanaiyaq pit. The samples were dry pulverized then split for elemental assay, Reactive Ground Catalyzed Adiabatic testing, Specific Heating Capacity (SHC) determination, and X-ray Diffraction (XRD) mineralogical analysis. From this data, a Red Dog Mine specific assay based classification for separating reactive from non-reactive ground was developed. Furthermore, it was possible to divide the reactive ground into two subgroups: i) rock which reacts with ANFO-emulsion blends even when manufactured specifically with a reactivity suppression agent like urea and ii) rock which reacts with ordinary ANFO-emulsion blends only when a reactivity suppression agent like urea is absent.

By Arnold Hague

In the short time allotted to me* I can only hope to present to you a brief sketch of the main geological features of the country which you are about to visit. My remarks must, of necessity, be more or less incomplete, as my desire is not so much to elucidate any special problem connected with the many interesting geological questions to be found here, as rather to offer such a general view of the region as will enable you, during your five days' trip through the Park, to understand clearly something of its physical geography and geology. The Yellowstone Park is situated in the extreme northwestern portion of the Territory of Wyoming. Its boundaries, as determined by the original Act of Congress setting apart the Park, are very ill-defined. At the time of the enactment of the law establishing this national reservation, the region had been but little explored, and its relation to the physical features of the adjacent country was but little understood. Since that time, surveys have shown that only a narrow strip, about two miles in width, was situated in the Territory of Montana, but it was also found that a still narrower strip extended westward into the Territory of Idaho. The question of properly establishing the boundaries, -based upon our present knowledge of the country, is now before Congress, and an Act has already passed the Senate, proposing to make the northern boundary coincide with the boundary between Wyoming and Montana, and the western boundary coincide with the Wyoming and Idaho line. The Act under consideration extends the southern boundary of the Park to the 44th parallel of latitude, carrying the area of the reservation southward nine and one-half miles. The eastern boundary is made to coincide with the meridian of 109' 30') adding a strip of country about twenty-four and one-half miles in width along the entire eastern side of the Park.

Jan 1, 1888

By N. A. Zeigler

The present publication is a continuation of the work on gas analysis described in a paper presented before the Institute of Metals Division year ago.' While that paper was largely descriptive in character dealing with the various parts of the apparatus and method of operations the present one gives numerical data obtained as a result of a series c experiments with iron-carbon alloys. The apparatus and the method applied are essentially the same as previously described, changes bein only in minor details. Attention should be called to the fact that in the present work we ar dealing with the gaseous mixtures obtained as a result of vacuum meltin of various ferrous alloys. It should be understood that when the term "degasified sample" and "products of degasification" are used, the refer to the sample remaining after the vacuum fusion of the alloy an the gaseous products removed therefrom, respectively. The write does not wish to create the impression that the metallic products of thj process are absolutely free from any gaseous elements, nor that the gase obtained are present as such in the original sample. These two point are not yet definitely known and are subjects for future investigatior The point, however, which has been established beyond doubt, i that all the gases dealt with come from the metallic charge and ar present either in the charge as such, or are produced as a result of chemic: reactions going on within the charge. The suggestion that the gases an due to the reactions between the metallic charge and the refractor materials has no valid basis. General Procedure A series of iron-carbon alloys was prepared in a magnesia-line graphite crucible placed in a high frequency laboratory furnace open t the atmosphere. The materials used were Westinghouse electrolyti iron and Acheson graphite. Each alloy, after it was completely molter was kept in the liquid state for 10 min., cast into a small iron mold, an

Jan 1, 1929

By Helvio P. G. Santafé Jr., Ruben J. S. Rodriguez, Sergio N. Monteiro, Teresa E. Castillo

"The coir fiber extracted from the husk of the coconut fruits are worldwide available in tropical regions as a low cost lignocellulosic by-product for many applications including composite filler in automobile parts. Possible uses above room temperature require information on the thermal behavior of these coir fiber composites. Therefore, the objective of this work was to perform thermogravimetric, TGA and DTG, analysis on polyester matrix composites incorporated with different volume fractions of coir fiber. In general, it was found that thermal degradation associated with weight loss occurred in three stages. Changes were also observed in the DTG peaks that could be attributed to the coir fiber participation through the decomposition of its lignocellulosic structure.IntroductionThe development of new materials has always been motivated by the need of improved properties. This was the case of modem composites with combination of properties that surpass those of conventional monolithic metallic alloys, ceramic or polymers, from which composites are made. A typical example is the synthetic fiber reinforced composite with specific strength i. e, ultimate stress divided by density, higher than any other monolithic material. Today, however, our global society is concerned with serious environmental problems and thus demanding that new materials be developed with distinct characteristics. They are known as environmentally correct and are expected to be sustainable, which corresponds to the condition of being biodegradable, renewable, recyclable and neutral with respect to C02 emission, considered the main responsible for global warning [1]. Synthetic fiber composites cannot meet these requirements. Consequently, new composite reinforced with cellulose-based natural fiber are being developed [2-8] and are already replacing the synthetic ones in several engineering fields including the automobile industry [9-11]. These composites have additional advantages owing to the lignocellulosic fiber benefits of being diversified, abundant, less expensive, lighter and of societal interest [8]. In some cases even technical advantages such as non-abrasive effect to processing equipments and more flexibility exist in comparison to synthetic fibers."

Jan 1, 2011

By B. MohammadSadeghi, S. Bakhshivash, M. Haghshenas, F. Rahimi

"Constrained groove pressing (CGP), as a severe plastic deformation (SPD) technique, is one of the applicable methods for sheet metal forming capable of producing ultra-fine grained materials (UFGMs). In CGP, processing and die design parameters can significantly affect the deformation response of sheet metal specimen. Having said this, in the present research the effects of die design variables and processing parameters (i.e. shear angle and friction) on the deformation behaviour of an Al-Mg-Si Alloy are studied thoroughly. Finite element analysis (FEA), was used to evaluate the effectiveness of mentioned parameters on the deformation homogeneity, strain distribution and pressing load variations. Also, mechanical properties of the deformed sample in term of micro-hardness was analyzed. It is observed that with increasing the shear angle, effective stress, strain and pressing load are enhanced. Moreover, by increasing the coefficient of friction, pressing load enhances. The color coded micro-hardness measurement showed a good agreement with the strain distribution obtained from FEA (higher hardness for the zones associated with higher shear plastic strain values).INTRODUCTIONWork hardening results in enhanced mechanical properties upon cycles of deformation (Hosford & Caddell, 2007). However, the formability of the processed products are affected by work hardening reducing the possibility of processing in subsequent deformation cycles. Therefore, many industrial processes cannot be performed on sheet metals to produce products with desired mechanical and physical properties (Valiev, Islamgaliev, & Alexandrov, 2000). Severe plastic deformation (SPD) is an effective grain refining technique which can impose large plastic strains through cold working on a metallic specimen (Bisadi, Rastgou, Payganeh, Zeynali, & Ghahremani, 2010). SPD techniques are mainly categorized into three types; sheet, bulk and tube forming. Among SPD sheet forming methods, Constrained Groove Pressing (CGP) (Shin, Park, Kim, & Park, 2002), Accumulative Roll Bonding (ARB) (Saito, Tsuji, Utsunomiya, Sakai, & Hong, 1998) and Repetitive Corrugation and Straightening (RCS) (Zhu, Lowe, Jiang, & Huang, 2001) possess potential applications in manufacturing industries."

Jan 1, 2016

By R. M. Brick, Arthur Phillips

The normal method of preparing metallic alloys for commercial use involves the preparation of a melt containing the given components in the chosen proportions and allowing the homogeneous liquid mass to solidify in a mold of the desired form. The solidification is frequently accompanied by a segregation of the alloying elements in different parts of the casting. When the segregation is occasioned primarily by marked differences in density of the solid and liquid phases, it is termed "gravity" segregation. When the segregation conforms to a selective freezing in harmony with the teachings of the equilibrium diagram of the alloy system—i.e., the lower melting phases are concentrated in the regions of the casting last to freeze—it is often referred to as "normal" segregation. However, in many cases the lower-melting part of the system is concentrated in the parts of the casting first to freeze and the result in this case is termed "inverse" segregation. To complete the terminology of the subject, normal segregation in a single phase is usually called "coring" and the word will be used in that sense in this paper. Inverse segregation, particularly when the liquid phase is exuded or sweated out on the surface of the casting, is sometimes called "liquation." Unfortunately, some ambiguity has arisen from the use of this term and it is perhaps advisable to confine its use to the dictionary definition; namely, "The separation of two phases by heat sufficient to melt one but not the other." The gravity and normal types of segregation are both well understood and to some extent, are controllable by taking advantage of the most favorable cooling rate for a given casting condition. Inverse segregation has received considerable attention from several investigators but none of the theories offered seem to account in a convincing way for the many examples of this type. The observations made in the present work on segregation in single crystals, and in some other castings, tend to support one theory of the mechanism of inverse segregation and definitely to

Jan 1, 1937

By John Garcia

COAL MINING, as well as all the other major in-dustries of Russia, is controlled by the Soviet Gov-ernment by means of organizations in each dis-trict, known as "Trusts," such as the "Kisel Coal Trust" in the Urals, the "Donugol Trust" in the Ukraine, etc., and each Trust functions as a unit, reporting direct to the chief of the department of the government at Moscow. The responsible head of each Trust is usually a mem-ber of the Communist party and, filtered through his organization, one generally finds a fair proportion of Communists in "key" or important positions, such as purchasing agents and local managers or superinten-dents, but in the majority of places requiring technical or professional knowledge, or trained brains and ex-perience, little or no attention is paid to a man's political opinion provided, of course, he "behaves himself." These different Trusts were authorized or ordered by the Central Committee at Moscow to investigate the methods of mining and type of mines developed in all other coal producing, countries of the world, and after a period of several years of intensive investigation and study reported back to headquarters that the modern American mines were the most efficient, recommending that the program for the rehabilitation of the Russian coal mining industry should follow the lines of American practice. The Trusts were then authorized to negotiate with American engineering firms for technical service for mine designs, and invited Americans to send commis-sions to Russia to prepare and submit to the Technical Council one or more projects for a complete modern American-type operation adapted to the local conditions. A "project" is a preliminary set of designs on the entire mine, top and bottom, with specifications. cost estimates, production costs, schedule of operation, budget of expen-diture, etc., and is quite an elaborate and sizable under-taking-I might say, it took six of us working tooth and nail for over three months to finish our first project.

Jan 3, 1928

KNOWING the endpoint, or the equilibrium state, in steelmaking reactions is only part of the story. The rate at which the reactions proceed can be equally important. But the power of thermodynamics, which enables us to estimate the endpoint, is that a knowledge of the mechanism is not required. The methods of kinetics, however, are step-by-step analysis in which a knowledge of the detailed reaction mechanism is essential. As is evident from Chapter 16, a great deal of thermo- dynamic data for steelmaking are available and the underlying theory rests on a completely sound basis. This is far from the case with kinetic data and even kinetic theory. Nevertheless, it is worthwhile to examine the present state of knowledge, to see how far it may be applied to electric furnace reactions. KINETIC THEORY Heterogeneous Reactions. Classical kinetic theory and experimentation have been mainly concerned with homogeneous reactions taking place between different chemical species in a gas or liquid phase. The species are mixed together and the progress of the reaction can then be observed. This is possible because most experiments have been done at relatively low temperatures where the characteristic time for the mixing process is much shorter than the time for the chemical reaction to be completed. For example, in the homogeneous gas reaction, H2 (g) + I2 (g) 2HI (g) hydrogen and iodine may be added to opposite ends of a tube containing a diaphragm. When this is withdrawn, gaseous diffusion (and convection) mixes the two types of molecule almost completely before any hydrogen iodide molecules begin to appear. Such an experiment is inconceivable at more elevated temperatures, since the rate of the chemical process is so sensitive to temperature that reaction would be completed almost instantaneously wherever hydrogen and iodine came into contact; the rate of the mixing process would then determine the rate at which hydrogen iodide was formed. We should not, therefore, expect to observe many homogeneous reac-

Jan 1, 1964

By E. J. Bartosh

In the brief period from November 1936 to September 1937, the Wilmington oil field developed far beyond all expectations. Decline in some wells appears very rapid, but it is too early to draw definite conclusions, as the majority of wells are maintaining very large and steady output. Heavy curtailment in the central area, which has developed the largest wells, makes it impossible to arrive at a satisfactory estimate of decline. The field is producing oil from the Repetto (lower Pliocene) and Puente (upper Miocene) formations, which are of the same age as formations producing at Torrance, El Segundo, del Rey or the marginal fields of the Los Angeles Basin. All of these fields are underlain by schist. The Long Beach field, northeast of Wilmington, is productive throughout 3000 ft. of Repetto-Pliocene series and also approximately 3000 ft. of Miocene formations, whereas at Wilmington only 700 to 800 ft. of Repetto and 2500 ft. of Miocene formations contain oil and gas. This paper gives a brief summary of the history and development of the field to Sept. 15, 1937, showing the subsurface conditions as they exist with the field only partly developed. History of Development The Wilmington oil field, 20 miles due south of Los Angeles, adjacent to Los Angeles harbor and about midway between the cities of San Pedro and Long Beach (Fig. 7), was producing oil as early as 1932 and only came into prominence as a major oil field of Southern California in the fall of 1936, when the General Petroleum Corporation of California completed Terminal well No. 1 from the upper Miocene, at a depth of 3625 ft., for a daily production of 1500 bbl., 20" gravity A.P.I., thereby establishing discovery of the Terminal zone. As early as 1925, or during the close of the development of Torrance oil field, a number of wells were drilled in the Main Street area looking for

Jan 1, 1938

By S. Huang, K. Xia

"During crushing, rock particle is subjected to complicated loading and the particle shape influences the fragmentation outcome. Thus, a highly controlled laboratory test is desired to establish the relation between the loading and the fragmentation parameters for better understanding the rock crushing mechanism. In this work, a split Hopkinson pressure bar system in combination with high speed cameras is utilized to carry out a dynamic ball compression test, in which the spherical rock sample is adopted to avoid the shape effect. Using the elasticity theory, the history of the axial symmetric tensile stress perpendicular to the diametrical direction along the loading axis is determined, from which the loading rate and the dynamic indirect tensile strength are calculated. With the aid of the moment-trap technique, the total energy absorbed by samples is accurately determined from the one-dimensional wave analysis. Furthermore by considering the kinetic energy of the sample fragments using the high speed camera snapshots, the surface energy is determined for each sample. The relations between the loading rate and the fragmentation parameters, i.e., the number of fragments and the surface energy are established. The application of this method to a granitic rock shows that it is flexible and can be applied to the crushing study of generic brittle solids. INTRODUCTIONCrushers are widely used to break rocks to extract specific minerals in the mining industry, and to obtain rock fragments with desired size distribution in construction industry. During crushing, the breakage of particles can be in either the single-layer mode or the multi-layer mode. In the single-layer mode, the particle breakage can be assumed to be isolated, in which the interaction between particles can be ignored. It is thus suggested by many researchers that highly controlled single particle test should be performed to establish the relation between the input mechanical energy and size reduction for better understanding the crushing mechanism (Yashima et al., 1987; Tavares, 2007; Pitchumani et al., 2004)."

Jan 1, 2015

By Darrell McClarty, Roger Payne, Matt Haggis, Michael Courtin, Deborah Berthelot

"Over forty years of uranium mining in the Elliot Lake region of Ontario (I 956-1996) has resulted in the production of over 300 million pounds of uranium. With the completion of mining activity, Rio Algom Limited and Denison Mines Limited are utilizing progressive environmental technologies and management systems to reduce and manage the environmental risks associated with the 150 million tonnes of potentially acid-generating tailings in nine regional waste management areas. Water covers designed to reduce oxygen entry and thereby significantly inhibit acid generation have been applied at six of the sites with the Quirke site serving as a demonstration site for the Mine Environmental Neutral Drainage program. All five of Rio Algom Limited' s effluent treatment plants are monitored and controlled from a central control station utilizing a Supervisory Control and Data Acquisition (SCADA) system based on ""Fix Dmacs"" technology. Scheduling, auditing and reporting of plant operating and environmental monitoring programs for the entire watershed are controlled utilizing the Regional Environmental Information Management System (REIMS). Proper application of these technologies and management systems facilitates delivery of cost-effective environmental monitoring, care and maintenance programs at these sites and provides tools to demonstrate compliance with all environmental performance criteria.IntroductionCost-effective management of multiple tailings management areas distributed throughout a 35 km watershed requires the application of leading-edge environmental technologies. Long-term monitoring, care and maintenance costs must first be minimized through the application of decommissioning technologies that inhibit acid generation and minimize the release of contaminants from the sites. On-going operating costs must then be controlled through the application of environmental management strategies that optimize the allocation of resources while ensuring compliance with regulatory and Company environmental requirements.Using sites in the Serpent River Watershed as an example, this paper demonstrates the effectiveness of water covers as a decommissioning strategy to inhibit acid generation. In addition, the Telemetered Environmental Operating Control System and Regional Environmental Information Management System are reviewed as examples of the application of environmental technologies to the management of environmental programs."

Jan 1, 1998

By T. Verdel, Y. Gunzburger

Rockfalls are major and essentially unpredictable sources of danger, particularly along transportation routes (roads and railways). Thus, the assessment of their probability of occurrence is a major challenge for risk management. From a qualitative perspective, it is known that rockfalls occur mainly during periods of rain, snowmelt, or freeze-thaw. Nevertheless, from a quantitative perspective, these generally assumed correlations between rockfalls and their possible meteorological triggering events are often difficult to identify because i) rockfalls are too rare for the use of classical statistical analysis techniques and ii) all intensities of triggering factors do not have the same probability. In this study, we propose a new approach to investigate the correlation of rockfalls with rain, freezing periods, and strong temperature variations. This approach is tested on three French rockfall databases, the first of which exhibits an outstandingly high frequency of rockfalls (approximately 950 events over 11 years), whereas the other two databases are more typical (approximately 140 events over 11 years). These databases come from (1) the national highway RN1 on La Réunion Island, (2) a railway in the Bourgogne-Franche Comté region, and (3) a railway in the Auvergne region. Whereas a basic correlation analysis is only able to highlight an already obvious correlation in the case of the “rich” database, the newly suggested method appears to detect correlations even in the “poor” ones. Indeed, the use of this method confirms the positive correlation between rainfalls and rockfalls on La Réunion Island database. This method highlights a correlation between cumulative rainfalls and rockfalls in the Bourgogne region, and it detects a correlation between the daily minimum temperature and rockfalls in the Auvergne region. This new approach is easy to use and also serves to determine the conditional probability of rockfall function of a given meteorological factor. This approach will help to optimize risk management in the studied areas based on their meteorological conditions. Nevertheless, even if some rockfalls are correlated to meteorological factors, other seems to occur independently of these factors, which highlights the unpredictability of rockfall hazard.

Jan 1, 2015

C. H. MATHEWSON, New Haven, Conn. (written discussion *).-In a recent discussion of Dr. Jeffries' paper on tungsten,1 J. C. W. Humfrey,2 after taking exception to certain of the author's ideas relative to the cohesion of A and C metal, expresses the opinion that future research is likely to develop a method of preparing tungsten possessing "mechanical properties in line with those of other metals." The present paper by Dr. Jeffries begins with a determination of comparative properties of tungsten, copper, and iron, in which much dissimilarity is apparent, and ends with a coherent explanation as to why much of this dissimilarity is natural and inevitable, thereby supplying theoretical means for visualizing the changing properties of metals in general, once certain fundamental facts are known. The author's reasoning is primarily from the standpoint of the amorphous theory and his principal achievement is the development of an idea f differential cohesion according to conditions of temperature, etc., between A and C metal (which was first plainly suggested by Rosehain and Ewen, in their papers on Intercrystalline Cohesion of Metals) along with associated ideas, so as to give us a really useful working theory. I have come rather reluctantly to believe in the amorphous theory, or some theory admitting a modification of the ordinary crystalline phase so as to permit differential properties within the conglomerate, mainly because in no other way does it seem possible to account for observed changes of properties with temperature, etc. The very best illustration f the competency f the amorphous theory in this respect is seen in this and other recent papers by the author. All fractures through normal or healthy metal that have been preceded by deformation are supposed, by Dr. Jeffries, to take place either through the amorphous phase or at certain boundaries between amorphous and crystalline material; his reference to fractures, both members of which are similar in appearance and do not reveal a preexisting coarse-grained structure because of a coating of amorphous metal, indicates his preference for the former interpretation.

Jan 5, 1919

By J. Campbell

The negative pressure developed within a solidifying sphere of pure iron is investigated theoretically assuming an elastic-plastic model. The maximum hydrostatic tension attainable is shown to be an order of magnitude smaller than that required for the homogeneous muclealion of pores in the liquid cove, and four orders of magnilude smaller than that predicted from) a rigid shell model. It is well-known that liquids can withstand large hydrostatic tensile stresses, or negative pressures. The various experimental investigations of the tensile strengths (often called the fracture pressures) of liquids are reviewed by Dean,1 and the theoretical attempts at estimating fracture pressures are critically assessed by wakeshima.2 Using Fisher's3 quation, the fracture pressure of pure liquid iron is about -70,000 atm, which may be too large by as much as a factor of 4, but is certainly correct to within an order of magnitude.' In view of the great importance of the problem of the nucleation of shrinkage cavities in castings it is of interest to determine exactly what tensile stresses can exist in the residual liquid in a solidifying casting; it has often been assumed that, because of the very low strengths of solid metals near their melting points, no interior stresses are developed at all. Nussey4 has determined theoretically the pressure in the liquid core of a solidifying metal sphere assuming that the solidified shell does not deform (i .e., is perfectly rigid), so that because of the contraction accompanying solidification (a) (about 3 pct for most metals) the progressive deposition of solid onto the inner surface of the shell causes the remaining liquid to be expanded to make up this difference in volume. This leads to a relation between the pressure P in the liquid, the initial pressure, PO, the bulk modulus of the liquid, K, and the inner and outer radii of the solid shell, o and b, respectively:

Jan 1, 1968

By Leroy Gardner

EVERY reader of this paper is well aware of the fact that the prolonged inhalation of large amounts of free silica dust results in fibrosis of the lungs, and that other inorganic dusts, except those of asbestos and the mineral poisons, are thought to be relatively harmless. But probably few have had opportunity to visualize the effects of silica, asbestos and other minerals upon living tissues. The ideal demonstration would be based upon sections of lungs from human beings that had inhaled com-parable concentrations of different dusts for a unit period of time. Such material is generally difficult to obtain and in some instances is of ques-tionable value because the subject has been exposed to more than one kind of dust. A demonstration could be prepared from the lungs of animals. However, so many months or even years are required to com-plete the exposure to each kind of dust that enough material has not been accumulated. For a general survey of the action of different types of dust, I am therefore compelled to use the tissues of animals that have been injected with suspensions of dust particles. The injection method offers certain advantages. The quantity, the particle size and the state of dispersion can be controlled with sufficient accuracy so that the tissue responses to different minerals can be accu-rately compared. The method insures contact between the tissues and the mineral particles; protective mechanisms, which may prevent the inhalation of certain types of foreign body, never come into play. If the pathway of injection be one that minimizes nonspecific injury, the tissue responses may simulate those produced by inhalation but they develop somewhat more rapidly. It should always be remembered that injection methods merely demonstrate the capacity of various kinds of minerals to provoke reaction in the tissues; whether the same substances are inhaled from atmospheric suspension and accumulate in the lungs in dangerous quantities can be demonstrated only by inhalation.

Jan 1, 1938