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By J. R. Lucas, H. E. Rutherford

The primary objective of this research was to evaluate the feasibility of ultrasonic testing for the purpose of analyzing the structure and properties of rock material. A secondary objective of this study was to determine experimentally the elastic wnstants of various rock specimens with the use of ultrasonic equipment. Elastic constants can definitely be determined quickly and accurately by ultrasonic investigation. With proper equipment there are indications that ultrasonic waves could be utilized in the detection of flaws, such as fractures and planes of weakness, measurement of thickness, and the study of structure of rock material. Ultrasonic principles have been applied in many industries for the purpose of determining the structural characteristics of various materials. The principal applications of interest here are detecting flaws, measuring thicknesses, and determining elastic constants. The main advantage of ultrasonic analysis is that it is nondestructive. It also has extreme sensitivity, high penetrability, good accuracy, rapid response, and the necessity to have access to only one side of the specimen. These various applications and advantages lead one to think that ultrasonic principles might be applied to rock material in situ for purposes of analyzing its structural characteristics. Therefore, the primary objective of this research was to evaluate the feasibility of ultrasonic testing for the purpose of analyzing the structure and properties of rock material. A secondary objective of this research was to determine experimentally the elastic constants of various rock specimens with the use of ultrasonic equipment. The term ultrasonics is given to that branch of acoustics dealing with periodic sounds whose fre- quencies are above the audible range or above approximately 15,.000 to 20,000 cps. The first practical production of this high frequency sound was made possible after World War I due to developments of electronically controlled sound wave sources. At the present, the maximum practically attainable ultrasonic frequency is approximately 1000 megacycles per sec. Sound waves of sufficiently high frequency can be made to travel in a beam with little spreading. Therefore, such a beam can explore a material and detect nonhomogeneities in it by reflection. This is the principle of the ultrasonic reflectoscope invented by F. A. Firestone' in 1942. An ultrasonic beam, on pulse-penetratink a solid material medium, produces an echo when it strikes a flaw which has different acoustical properties than the surrounding medium. This echo can be detected by the same transducer which sends out the original pulse. This principle is the basis of the important industrial techniques of nondestructive ultrasonic testing of metals and other solid material. Later developments in the field of ultrasonic testing of solid material have been mostly improvements in equipment and instrumentation. To date, most of the industrial applications of ultrasonic analysis of solid bodies have been in the aircraft, electrical, and nuclear energy fields on the nondestructive testing of metal. The one solid material similar somewhat to rock material, upon which some work has been done to apply ultrasonic testing techniques to study structural integrity, is concrete. Jones and Gatfield3 briefly summarize this work on concrete. Their basic conclusion was that the strength of concrete was a function of the change of the longitudinal sound wave velocity in the concrete. Only recently has any extensive study been made to apply ultrasonic testing techniques to rock material. Lutsch studied rock material by an ultrasonic pulse method to determine the extent and degree of fracture of rock faces. Lutsch states that the number of observed reflections is a measure of the degree of fracture and that only ultrasonic waves are able to detect fractured zones subjected to high pressure. Suzuki, Sasaki, and Siohara5 studied the characteristics of the sonic wave in rock for propagation over a wide range of wave lengths. They indicated that, in rock, the propagation constant and attenuation of the

Jan 1, 1962

THE increased demand for titanium alloys with improved high-temperature creep strengths has stimulated interest in silicon as an alloying addition to titanium. Silicon is a potent solid-solution strength-ener and, if added in sufficient concentration and properly heat-treated, can also dispersion-strengthen titanium by eutectoid decomposition.' However, better understanding of the nature and distribution of the resulting silicide dispersion in more highly alloyed titanium matrices is necessary for the development of useful titanium alloys which utilize the latter strengthening mechanism. This note describes the chemical and crystallographic characteristics of the silicide phase as it occurs in a typical high-temperature near-a titanium alloy matrix. Several Ti-6A1-3Sn-3Zr a11oys containing various amounts of silicon ranging from 0.1 to 1.0 pct were melted as 10- to 20-lb ingots and processed into 1/2-in.-diam bar stock. The microstructures of specimens annealed at various temperatures were conveniently summarized by the (Ti-6Al-3Sn-3Zr)-Si pseudobinary phase diagram illustrated in Fig. 1. Comparison with the Ti-Si equilibrium diagram indicates the substitutional solutes (Al-Sn-Zr) increase the eutectoid temperature and decrease the a terminal solubility. Annealing at temperatures sufficiently high to dissolve the silicon in a ß solid solution and cooling rapidly enough to preclude coarsening generally produced a uniform dispersion of fine silicide particles, whereas annealing at temperatures near but below the ß transus produced relatively coarse silicide particles. Annealing in the limited a, plus 3 region produced a duplex coarse and fine silicide array. Several a-annealed specimens were examined by X-ray diffraction to determine the crystallographic identity of the precipitate phase. Copper Ka X-ray diffraction patterns of bulk specimens which contained 0.5 and 0.8 pct Si were virtually identical to that of the silicon-free Ti-6Al-3Sn-3Zr base alloy except for a slight shift in some of the high-angle diffraction lines. Apparently the silicide volume fraction was too low to be detected in bulk specimens. X-

Jan 1, 1969

By W. S. Hyler, W. L. Bruckart

The powder metallurgy and arc-cast types of wrought molybdenum stock were studied in rotating beam fatigue. Endurance ratios of unnotched specimens after 5x10 cycles were found to be 0.74 and 0.81, respectively. Fatigue notch factors (K,) of 1.36 and 2.05, respectively, were obtained on V-notched specimens having a theoretical stress-concentration factor Kt = 3.1. MOLYBDENUM and its alloys are rapidly gaining importance as engineering materials of construction for high temperature applications. AS a wrought material, molybdenum and its alloys are outstanding above 1800°F. It is necessary, however, with molybdenum to provide elevated temperature oxidation protection. This is currently being studied by a number of investigators. Thus far, there have been no published data on the fatigue behavior of molybdenum either at room temperature or at elevated temperature. The knowledge of fatigue behavior, particularly notched fatigue behavior, becomes increasingly important as the engineering importance of a material increases, especially from the design standpoint. The work described here was directed toward determination of the notched and unnotched rotating beam fatigue characteristics of molybdenum at room temperature. Also, it was desired to learn whether any difference exists between wrought molybdenum of the powder metallurgy and the are-cast types. Fabrication History of Bar Stock For this work, bar stock was procured from Climax Molybdenum Co. (are-cast type) and from Westing-house Electric Corp. (powder metallurgy type). The processing histories of these materials are listed in Table I. The first lot of are-cast molybdenum was deoxidized by aluminum additions. The second lot was deoxidized by carbon." Both lots of the powder Microstructure A microscopic examination of these materials, as received, revealed the powder metallurgy molybdenum to be free of inclusions and to be finely fibered. On the other hand, the are-cast C molybdenum possessed numerous carbide inclusions, and the arc-cast A appeared to have coarse grained fibers. These are shown in Fig. 1. Owing to the large apparent difference in fineness of fiber between the are-cast A and the powder product and are-cast C, a check was made of the recrystallized grain sizes to determine whether these differences persisted. A series of recrystallization anneals revealed mixed grain sizes in both the are-cast A and the powder product. Variations in grain diameter of as much as 50 times were found after full recrystallization at 1200°C for 30 min. There was no distinction between the two. Arc-cast C was not checked. Room Temperature Mechanical Properties Prior to subjecting the materials to fatigue tests, room temperature mechanical properties were determined. These data, together with the tensil: strength of the notched bars, data,togetherare listed in Table tensil: There were no significant differences in the tensile strengths of the two types of molybdenum. However, the powder metallurgy material was generally more ductile and yielded at a somewhat lower stress than the arc-cast material. Tensile strengths of the notched specimens indicated a slightly greater notch strengthening effect in the are-cast C than in the powder product, lot 2. Room Temperature Fatigue Properties Sample Preparation: Specimens were prepared for use in R. R. Moore rotating beam fatigue machines. These specimens had a continuous radius test section with a minimum diameter of 0.260 in. The specimens were prepared by grinding to shape and polishing to produce a smooth unworked surface. Polishing consisted of rotating a disk in the continuous radius section on which were attached, successively, emery belts of 240, 400, and 600 grit. The specimens were slowly rotated during the operation. The belt speed was high, and rotation was such that polishing scratches were longitudinal. Unnotched Fatigue Properties: Unnotched fatigue data were obtained from a number of specimens of each of the four lots of molybdenum. The results of the tests are presented in Fig. 2. From this figure,

Jan 1, 1956

By Tae-Hyun Kim, Kang-In Rhee, Jeong-Soo Sohn

The synthesis of Mn-Zn ferrite powder from spent zinc-carbon batteries was investigated using a series of physical treatment, sulfuric acid leaching and coprecipitation. Physical separation methods such as crushing, magnetic separation and sieving were applied to generate a non-magnetic material of 8- mesh undersize for subsequent leaching process. The 8-mesh undersize of the spent zinc-carbon batteries was assayed 23.9% Mn, 14.9% Zn, and 4% Fe. Metal extractions obtained in sulfuric acid leaching at the solid/liquid ratio of 1:10, 2 M H2SO4, and 60? with 6 vol.% H2O2 addition were 97.9% Mn, 98.0% Zn and 55.2% Fe. The leach liquor was finally adjusted to the Mn:Zn:Fe mole ratio of 1:1:4 suitable for producing MnZnFe4O8 ferrite powder by the addition of Mn, Zn and Fe sulfates followed by pH control. A co-precipitation test for Mn-Zn ferrite powder was performed at 80?, O2 gas flowing at 1.3 L/min. As a result of co-precipitation, Mn-Zn ferrite nanoparticles in 20 nm size with spinel structure were successfully synthesized. The saturation magnetizations of Mn-Zn ferrite powder (Mn1-xZnxFe2O4) were determined to be 39-91 emu/g with various zinc contents (X=0.2-0.8).

Jan 1, 2008

By D. John Curtis, Gordon S. Crighton, John C. Hester

The six main drives needed to build 55 miles of 4.8 and 7.7 metre i.d. tunnels in 33 months called for careful co-ordination of the design of tunnel boring machines and linings. The implications of these requirements are discussed, with particular reference to the selection of tunnel liners. The solutions adopted are detailed and details are given of the specifications and procedures adopted. The design methods employed for liners are outlined. The construction methods are described and current performance figures given.

Jan 1, 1991

By C. M. van der Walt, J. F. van Rensburg, H. J. Groenewald

The South African platinum group metals mining industry faces considerable operational costs, with compressed air networks’ annual costs accounting for up to 35% of total electricity consumption. Amidst escalating electricity tariffs and volatile commodity prices, enhancing energy efficiency has become critical for economic sustainability. This study addresses the prevalent issues of mismanagement and inefficient use of compressed air on the demand side, such as leakages and unauthorised use for ventilation. While previous research has identified these inefficiencies, a gap exists in the continual monitoring and reporting of network performance to drive sustained improvements. This paper presents a practical solution developed and applied within a major South African platinum group metals mining group. The methodology focuses on a continual monitoring and reporting framework to improve demand-side management. The implementation of this solution has demonstrated significant financial and energy-saving potential. Key findings from case studies include: 1) the mitigation of R150,000 in costs over five days by rectifying a single instrumentation fault, 2) a potential annual energy saving of up to 5.6 GWh (R10.6 million) by enforcing valve closures during non-productive periods, and 3) an annual reduction of 3.7 GWh (R7.2 million) through improved underground ventilation controls. These outcomes underscore the value of a systematic, data-driven approach to managing compressed air consumption, offering a viable strategy for cost reduction and enhanced efficiency across the platinum group metals industry.

Mar 6, 2026

By E. M. Timoshenko, A. V. Tarasov

The results of laboratory, bench-scale and semi-commercial investigations of a method for adding surfactant (technical-grade lignosulphonate) to the process of pressure leaching of nickel-containing pyrrhotite concentrates have been discussed. Lt has been demonstrated that feeding of technical-grade lignosulphonate distributed along the length of an autoclave ensures a reduction in its requirement by a factor of 1.5 to 2 as compared with single-point feeding; it also results in a decrease by 5% in the unit requirement of metallized iron-bearing precipitator in the process of non-ferrous metals precipitation and reduces by 0.05 to 0.1% (abs.) the nickel and copper contents in the tailings of the given process. Technical solutions have been proposed for commercial introduction of the process.

Jan 1, 2004

By L. A. Schutz

Personnel of the Bureau of Mines have conducted investigations in the principal asbestos mines and mills in the United States, to determine the concentration of airborne asbestos fibers in the workplace, and to establish the exposure of workers to such fibers. 'The surveys were conducted using the sampling and evaluation method recommended by the National Institute for Occupational Safety and Health. The method consists of collecting the air-borne sample on filters and, after appropriate sample preparation, counting the fibers utilizing phase contrast microscopy. The results of the investigation show that fiber concentrations are low in the asbestos mines but high in the asbestos mills, ranging well above 5 fibers/ml of air based on a count of fibers greater than 5 urn in length.

Jan 1, 1973

By A. S. Block-Bolten

Two innovations in nickel-arsenic separation have been studied on a laboratory scale. The first requires only a nitric acid atmospheric leach without preliminary roasting and leads to favorable final conditions for precipitation of arsenic as highly stable FeAsO4, The second is an NaOH-H2O2 pressure leach which is an alternative to the known NaOH-O2 pressure leach. Either method offers the possibility of rapid and efficient separation of nickel from arsenic and is applicable, for example to the high grade niccolite deposits in the Great Slave Lake area of northern Canada.

Jan 1, 1982

This paper describes the MillMapper technology developed for condition monitoring of liners and other operational parameters in grinding mills used for mineral comminution, by presenting a case study of its application. MillMapper provides maintenance engineers, operations managers and process and plant metallurgists with quantitative, accurate and reliable condition monitoring data for informed decision making regarding the maintenance and metallurgical aspects of such mills. MillMapper uses calibrated laser scanners for the capture of three-dimensional surface representations inside a mill during a shutdown so as to determine shell, feed and discharge liner thickness at a resolution of several million data points, a procedure that nominally takes five minutes to complete. Once several data sets over time have been collected inside a mill, MillMapper can be used for liner wear, liner wear zone, liner weight, ball charge volume, ball charge weight and intelligent profile tracking over time. Liner tracking in combination with site defined reline and failure criteria and with throughput tonnage data is utilised for change out prediction of each separate liner segment type.

Jan 1, 2008

By A. W. Fahrenwald

The physics and chemistry of the flotation process are not well understood. Many papers dealing with the theory of flotation have been published but most have been narrow in their viewpoint. No theory advanced has done more than explain, more or less satisfactorily, various isolated phenomena. Scientists have done little with the problem, doubtless because they have not seen sufficient of the practical side of the subject to have their interest aroused. Any attempt to explain the mechanism of flotation that considers only contact angles, surface tension, adsorption, the floating of needles, flocculation, or any other single and narrow phase of the question is sure to be disappointing. Flotation is a problem of colloid chemistry and must be studied as such. In a broad general way, flotation is a process involving and operating by virtue of surface reactions. The term "surface reactions" may be open to criticisms. Many chemists give the term "reactions" a definite and restricted meaning and to such the term may connote change in atomic grouping in strict stoichiometric ratios. While Langmuir looks upon adsorption as a reaction, and there is much evidence in support of this view, we may look on adsorption as a physcial process as far as this paper is concerned. The term seems well suited to the work in general. Presumably these reactions are reactions between the same kinds of forces (electrical) and differ only in degree and in the surface manifestations produced. This premise seems logical if we accept the theory that the atoms of dl elements are made up of grains of electricity, having mass and charge, called electrons; and that atoms differ from one another only in the number and arrangement of the electrons about a positive nuclear

Jan 1, 1924

By R. D. Pehlke, W. M. Small

The effect of added alloying elements on the solubility of nitrogen in a liquid alloy of 74 wt pct Fe. 18 wt pct Cr, and 8 wt pct Ni has been studied. At 1600°C and 1 atm nitrogen pressure, aluminum, chromium, columbium, manganese, molybdenum, tantalum, and vanadium increase the solubility of nitrogen in the liquid 18 Cr-8 Ni alloy, whereas additions of cobalt, copper, nickel, silicon, tin, and tungsten decrease the solubility. Interaction parameters based on a constant ratio of iron, chromium , and nickel have been used to quantitatively define the changes in nitrogen solubility. INVESTIGATIONS on the solubility of nitrogen in liquid iron have usually treated the pure metal, and often the influence of a single added element. Pehlke and Elliott1 carried out a comprehensive study on the influence of alloying elements on nitrogen solubility in liquid iron, and compared their results with previous studies. Turnock and pehlke2 have recently reported a study on the solubility of nitrogen in multicomponent liquid iron alloys. The original interaction parameter proposed by wagner3 was successfully employed in these studies. The need for obtaining information on the gas solubility in more complex alloys is indicated by the increasingly significant role played by dissolved gases in the processing of iron-based materials. The commercial stainless steels, for example, represent an area where data on nitrogen solubilities are required as a function of composition, temperature, and gas pressure. The nitrogen solubility in liquid Fe-Cr-Ni alloys has been studied by Humbert and Elliott.4 Their investigation covered the entire ternary system, and attempted to use data from binary alloys to predict nitrogen contents in liquid ternary alloys. Langenberg,5 using a method developed by Morris and buehl,6 calculated the nitrogen solubilities in multicomponent iron alloys from data available on binary iron alloys at 1600°C. Nelson,7 using a regular-solution model, extended this prediction to include the effect of temperature. Chipman and corrigan8 and Turnock and pehlke2 also employed empirical methods to calculate nitrogen solubilities in liquid multicomponent iron alloys. In order to provide a basis for predicting nitrogen solubility in liquid stainless steels, and to extend the data available for thermochemically modeling systems of this type, the following investigation was carried out. The study involved measupements of nitrogen solubility in a nondilute alloy and examination of the influence of a small addition of an alloying element on the nitrogen solubility. The study was focused on a very narrow range Of composition in the vicinity of 18 wt pct Cr-8 wt pct Ni (herein referred to as 18-8) with special emphasis on the change of.nitrogen solubility with the addition of a fourth metallic element. EXPERIMENTAL PROCEDURE A Sieverts' apparatus, described previously,1,2 was used in this investigation. The charge materials were contained in a recrystallized alumina crucible and inductively melted. Additions were dropped from a glass side-arm. All materials were hydrogen-refined and vacuum-treated to eliminate or minimize the oxygen content. The source and purity of materials is given in Table I. The initial metallic charge was heated to approximately 1000°C and held under vacuum for 30 to 45 min as a means for removing hydrogen and adsorbed gases. Argon was used as the calibrating gas to determine the "hot volume". The average hot volume of the system was approximately 50 cu cm STP and a few experimental runs were made using a reaction bulb with a hot volume of 80 cu cm. The temperature range studied was from 1550° to 1700°C and the temperature was measured optically. THEORETICAL PRINCIPLES General Discussion. Nitrogen dissolves in liquid iron alloys according to the reaction: 1/2N2(g) = N (wt pct in solution) [l] The equilibrium constant, K1, for this reaction is written as:

Jan 1, 1969

By H. Foster Bain

This is the third volume of the collective index of the Transactions Each volume is indexed and the indices of Volumes I to XXXV have been collected into a single index volume, similarly the indices of Volumes XXXVI to LV are collected in a single volume This index covers Vol¬umes LVI to LXXII, and the three index volumes together cover all the volumes of Transactions published from the organization of the American Institute of Mining and Metallurgical Engineers in 1871 until the end of 1925.

Jan 1, 1926

By C. B. Alcock, R. G. Hudson

Sulfur pressure measurements above FeS in equilibrium with iron have been carried out by the Knudsen orifice method. A comparison is made of the weight loss of the cell per unit time obtained in the above experiments, that calculated from Richardson and Alcock's measurements of the S2 pressure above FeS in equilibrium with iron, and the dissociation constant for diatomic sulfur from spectroscopic and thermal data. EXTENSIVE equilibrium measurements have been made to determine the sulfur potentials of a great many systems of metallurgical interest.' In order to confirm their reliability, to supply data which may be of use in further thermodynamic calculations, and to establish the reliability of the Knudsen orifice in obtaining accurate thermodynamic values at high temperatures, the present investigation on the pressure of the gaseous species above FeS in equilibrium with iron has been carried out. The Knudsen orifice method has been used for these pressure measurements. Experimental The apparatus and general technique for this investigation are the same as that reported for the determination of the vapor pressure of silver.' To reduce the residual gas pressure in the evacuated chamber, a titanium getter, maintained at run temperature, was introducbed. Several types of Knudsen cells were used—platinum, zircon, and fused silica. The orifice in the zircon cell was fashioned with a small diamond wheel. The same precautions were used in this investigation as were employed in the work on Mo2S2.3 The FeS-Fe mixture was prepared by heating a sample of pure FeS,, supplied by K. K. Kelley of the Bureau of Mines, with excess iron powder, cp grade, obtained from the Fisher Scientific Co. These two substances were heated in a closed Armco iron crucible at 960°C, held in a vacuum of less than 10" mm Hg for 24 hr. The mass was then removed from the cell and ground in an agate mortar. In this form it was charged to the various Knudsen cells. Heating the Knudsen cell for an additional two days was sufficient to obtain constant rates of weight loss of the cell. The data obtained in this investigation are recorded in Table I. To establish whether or not a sulfide of iron is volatile at these temperatures, 0.7646 g of the FeS-Fe mixture, described above and containing 69.2 pet Fe, was placed in the zircon Knudsen cell. Run Nos. 103 to 109 were performed on it. After the completion of these runs, the total amount of iron left in the cell was obtained by chemical analysis. It contained 0.537 g Fe, compared to 0.529 g in the original charge. Thus, there was an apparent gain in iron of 1.5 pet. This is attributed to unknown experimental error, and the conclusion is that no sulfide of iron is volatile. The vapor pressure of pure iron4 is about one thousandth that of the sulfur pressure' at these temperatures. The vapor pressure of iron inside the Knudsen cell will be almost exactly that of pure iron, since in the iron-rich phase the percentage of sulfur is of the order of 0.025 pet.At this low percentage of sulfur Henry's law is probably obeyed by the sulfur. Thus, the iron will obey Raoult's law. In any event, the vapor pressure of iron will be lower than that of pure iron and, since the vapor pressure of pure iron is negligible compared to the pressure of sulfur, the weight loss of the cell due to the vaporization of iron should be negligible. Since neither iron nor FeS is volatile to an appreciable extent, the total weight loss of the cell must be due to the vaporization of sulfur. Discussion and Calculations On the assumption that S, is the only gaseous species present in appreciable quantity, its pressure

Jan 1, 1957

By Kirkhouse C. B

Soon after the Broken Hill Limited started operations at their Iron and Steel Works at Newcastle, NSW, it was found necessary to install a mill for rolling small merchant bars, rounds, etc.An arrangement of the first mill laid down is shown on Plate 1., Fig. 1. This mill commenced operations on the 18th July, 1917.The feed for this mill was rolled in the existing 18-in. mill and sheared to the lengths required before being delivered to the billet storage yard. The billet storage yard is 90 ft. span, and is served by one 10-ton electric overhead travelling crane. Billets were placed on the billet bed preparatory to being charged into the heating furnace.The heating furnace was of the continuous recuperative with end discharge and had a hearth 40 ft. long by 10 ft. wide. The billets were pushed through the furnace by means of two hydraulic rams, which could either act together and push one row of billets, or act singly and push two rows of billets. This furnace was fired by producer gas from the producers shown on Plate I., Fig. l.The gas was conveyed to the furnace by means of a brick underground flue.

Jan 1, 1935

By A. W. Deurbrouck

This Bureau of Mines report describes the washability characteristics of 14 coalbed samples collected in Wyoming. Such data is needed to evaluate the quality of the coals of the West where most of our low-sulfur-content coal reserves are found. Of the 14 samples included in this report 13 had a total sulfur content of 1.1 percent or less. All of the samples contained low per¬centages of ash or could be readily washed to a desirable ash level with minimal loss of yield. The coals ranged in rank from high-volatile B bituminous to subbituminous C, although 10 of the samples were high-volatile C bituminous. The coalbeds varied in thickness from 4.5 to an unknown thickness greater than 67.5 feet.

Jan 1, 1971

By Eugene McAuliffe

It is not possible to include in this paper, limited as it is in scope, the many diverse steps toward the reduction of mine accidents that are taken in the mines that produce the nation's coal. Every coal-producing state has enacted laws covering proper mining practices, and the major portion of these are directly related to the safety of the mine employees. The United States Bureau of Mines, the American Institute of Mining and Metallurgical Engineers, The American Mining Congress, a number of national, regional and state organizations, as well as the coal technical press, have covered time and time again all of the '(do" and "don't" phases of mine operation that bear on the important question of mine and employee safety. Within the past 15 years The Union Pacific Coal Co, has attempted to put into practice in its mines in southern Wyoming these many good recommendations, finding some value in all, and yet, to secure substantial results, the management found it necessary to resort in the end to what might be referred to as i'extra-territorial" methods. It is the writer's purpose to show in this paper that marked and even extraordinary betterment, can be brought about when employer and employee work together with due sincerity. In presenting our own experience, one that has been duplicated in so far as results are concerned on numerous other properties, no theory of perfection of management exists; on the other hand, our organization feels that as long as our record of accidents remains as shown by even our latest and best performance we still have far to go. Safety work in some form has been carried on in and about the mining properties of The Union Pacific Coal Co. since the first mine was opened at the now long-abandoned town of Carbon, Wyo., in 1868. On June 30, 1903, an explosion and subsequent mine fire occurred in mine No. 1 at Hanna, taking 169 lives, and a second explosion occurred in the same mine on March 28, 1908, in which 59 additional lives were lost. Looking back with impartiality on the causes leading up to these two unfortunate disasters, we can only conclude that shooting from the solid, the absence of adequate ventilation, rock dusting, the use of water at the face to allay

Jan 1, 1938

By Eugene McAuliffe

It is not possible to include in this paper, limited as it is in scope, the many diverse steps toward the reduction of mine accidents that are taken in the mines that produce the nation's coal. Every coal-producing state has enacted laws covering proper mining practices, and the major portion of these are directly related to the safety of the mine employees. The United States Bureau of Mines, the American Institute of Mining and Metallurgical Engineers, The American Mining Congress, a number of national, regional and state organizations, as well as the coal technical press, have covered time and time again all of the '(do" and "don't" phases of mine operation that bear on the important question of mine and employee safety. Within the past 15 years The Union Pacific Coal Co, has attempted to put into practice in its mines in southern Wyoming these many good recommendations, finding some value in all, and yet, to secure substantial results, the management found it necessary to resort in the end to what might be referred to as i'extra-territorial" methods. It is the writer's purpose to show in this paper that marked and even extraordinary betterment, can be brought about when employer and employee work together with due sincerity. In presenting our own experience, one that has been duplicated in so far as results are concerned on numerous other properties, no theory of perfection of management exists; on the other hand, our organization feels that as long as our record of accidents remains as shown by even our latest and best performance we still have far to go. Safety work in some form has been carried on in and about the mining properties of The Union Pacific Coal Co. since the first mine was opened at the now long-abandoned town of Carbon, Wyo., in 1868. On June 30, 1903, an explosion and subsequent mine fire occurred in mine No. 1 at Hanna, taking 169 lives, and a second explosion occurred in the same mine on March 28, 1908, in which 59 additional lives were lost. Looking back with impartiality on the causes leading up to these two unfortunate disasters, we can only conclude that shooting from the solid, the absence of adequate ventilation, rock dusting, the use of water at the face to allay

Jan 1, 1938

By John B. Hastings

THE origin of the watery vapors of vulcanism has always been an object of interest and speculation to the seismologist, and as theories of the genetic origin of ore-deposits have of late years been pretty well narrowed down to the expiring forces of plutonic action, the same question has had a lively interest for mining engineers and geologists, as is well shown by the discussions of the subject in our Transactions. The important part taken by volcanic emanations in the origin of pegmatites and quartz-veins, described in my paper, Origin of Pegmatite,1 and their latent power to concentrate into useful deposits such scattered gold as occurs in the Hartsel granite, make a discussion of their derivation but a natural third and final step. It is conceded that enormous amounts of vapor accompany volcanism, though perhaps we are apt to forget that steam has 1,700 times the volume of water, besides which the column seen over Vesuvius and other volcanoes is greatly mixed with air; the immensity of such volumes compared with solids and liquids is shown by the experiment of Gautier, who, by heating dessicated granite to 100° C., evolved from it uses 20 times, and steam 90 times, its own volume. Dana appraised the average amount of water left in ordinary rocks as 2.5 per cent. T. M. Read estimated that the Mississippi river carries to the sea annually 150,000,000 tons of rock material. If these Mississippi sediments, as deposited, contained 20 per cent. of water, it would be 600,000,000 cu. ft., or 4,500,000,000 American gallons, annually. Allowing the vapor suspended over a volcanic cone to be mixed with 80 per cent. of air, this amount of water converted into steam would replenish anew, every 9 min., a column 15,000 ft. high, 2,000 ft. in diameter at the base, and 10,000 ft. at the top. Read's estimate is only half of the amount given in a more recent and probably correct one .2

Jan 5, 1908

Oceana Gold CorporationÆs (OGC) Frasers underground (FRUG) transitioned into production in early 2008. The mine uses a relatively unique yielding pillars mining method that takes its lessons from empirical coal mining practices more so than hard rock techniques. Being a low-grade, flat-dipping resource hosted in the highly structured relatively weak Otago schist in central South Island in New Zealand, meant a number of iterations were undertaken to find the right mix of mining cost and resource extraction. Mining is on the down dip extension of the active Frasers open pit at the Macraes site (that extracts the full shear zone package at a head grade of 1.5 g/t). The challenges for the FRUG feasibility study team was to deliver an net present value (NPV) positive operation that would exist as a coproduct with OGCÆs other New Zealand operations, allowing it to make use of the high throughput low cost refractory ore treatment facility.Key factors in the successful project design were: Net capital costs kept to less than NZ$30 M by realising significant gold revenues from mine development from month four onwards. Virtually eliminating waste development by putting all key capital infrastructure in the low-grade ore adjacent to panels and maintaining the option of extracting this resource on retreat from the mine. Targeting a specific higher grade halo ore package within the entire mineralised shear zone. Applying a mining method that accepted a higher degree of dilution, ore loss and resource loss (in yielding and non-yielding pillars) to the flat-dipping resource. Thus providing an acceptable margin per tonne and resource tonnes mix, as the resource could not support a conventional low-cost caving operation, nor a higher cost room and pillar or open stope and backfill operation. 2008 has seen increasing tonnes and grade performance with a corresponding decrease in cost per tonne and cost per ounce as the mine has reached nominal capacity and is producing an operating surplus. The challenge will be to maintain and improve.

Jan 1, 2009