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Jan 1, 1934

By Pat C. Hautala, J. R. Hoskins

This is a new era for the minerals industry. Never before has there been more need for effective communication. So said Robert Anderson, chairman and chief executive officer of Hanna Mining Co. He was speaking to the American Mining Congress's Communication Workshop. The question is whether there is enough industry concern to meet the challenge. Anderson observed that increased workshop attendance, in continuing tough times, reflects the industry's concern for communication. But, why were students, faculty, engineers, supervisors, and managers not at the conference? Communication applies to every manager, Anderson said. But he was the only operating manager present. And only one company sent operating supervisors. The remaining conference participants were public relations personnel, generally with nonmining backgrounds. And the program dealt mostly with public relations issues. Role of Communication in the Minerals Industry. It is well known that the minerals industry faces economic, political, and social problems. Economic shifts and foreign competition have created an international minerals industry and an international marketplace. This, in turn, calls for worldwide communication. Other factors effecting communication are: • Governmental protectionism as well as regulatory reforms call for increased interaction with governing officials. • Changing social values have created environmental issues and anti-industry attitudes. This intensifies the need for improved public relations. • Traditional work values are shifting towards self-actualization and humanistic movements. The work force is better educated and more informed. Employees demand more satisfaction, equality, and job autonomy. • The mining industry's task of managing its human resources is complicated by layoffs, job uncertainties, and bleak outlooks concerning employee morale and motivation. Technology and Information for a New Era As noted, this is a new communications era, one propelled by technology and information. Technology has led to reduced demand for raw materials by developing substitutes. Copper demand, for example, will never fully recover. Copper cables are replaced by fiberoptics; copper transmission lines, with aluminum. Technology has shifted the US from traditional to high tech and service industries. The speed, frequency, and scope of information transmission have greatly increased. But the most significant characteristic of this information is not the pace of advancing technology. It is the dramatic increase in the importance and frequency of our personal transactions. Knowledge has replaced raw materials and capital as the strategic resource. Information has replaced energy as the transforming resource. And the game against nature has become an interpersonal game (D. Bell, Post-industrial society, Physics Today, '76). In Megatrends, John Naisbitt says that information will soon double every 20 months. So, professionals will become "information workers." And communication will be the life channel of the information age. Thomas Wolfe said you can't go home again. Hanna Anderson said we are, indeed, facing a new day. It will never again be "business as usual." We must move into the information age with the rest of society. We cannot trust that the world will continue to rely on our products. Nor can we place the responsibility and control for problems and solutions outside the minerals industry. Improved communication is not a panacea. But, Anderson said, it is critical to the minerals industry. What is Communication? The word communication is overused. It is applied to every aspect of our lives. Satirist Tom Lehrer got sick of hearing about the need to communicate. He said, "It seems to me that if someone is having all that trouble communicating, the very least he can do is shut up!" Obviously, we cannot follow that advice (though we might wish that some others would do so). Communication is always going on. It is inevitable. Yet we have many misconceptions about com-

Jan 1, 1985

By Rahul Bhaduri

Mercury levels in Twin Creeks Vista pit ore (previously Chimney Creek, North pit ore) increased substantially since plant start-up in November 1987. Consequently, modifications were necessary to minimize industrial hygiene hazards and potential operational problems. The original plant design included mercury control measures. With progressive increases in mercury levels, the issue had to be re-addressed. Modifications to operational practice, industrial hygiene and management philosophy will be discussed. Additionally, a detailed examination of the mercury vapor suppression system currently employed at Twin Creeks will be presented.

Jan 1, 1994

By E. A. Gulbransen, W. S. Wysong

The behavior of molybdenum and its surface oxides in oxidizing and reducing gas atmospheres and in high vacua at elevated temperatures is a question of scientific and technical importance. The use of molybdenum as a metal or as an important component in alloys in oxidizing atmospheres at elevated temperatures has been limited because of the unprotec-tive nature of its oxide film and the volatility of this oxide at moderate temperatures. This communication will present results of a vacuum microbalance studyl, 2 of the following problems: (I) the oxidation kinetics in the temperature range of 250°to 450°C; (2) the reduction with pure hydrogen of thin oxide films formed on molybdenum; (3) the volatility of the thin oxide films; and (4) the vacuum oxidation of molybdenum at high temperatures. Molybdenum is an interesting metal to study for the following reasons: (I) although the oxide-to-metal-volume ratio is greater than one, the metal is not considered protective; (2) the metal oxidizes readily at temperatures of 2 50°C and higher; (3) the oxides of the metal are reduced at temperatures as low as 500°C by pure hydrogen; (4) the oxide Moo3 melts at 795°C; and (5) the oxides of molybdenum are volatile at moderate temperatures. The following variables are studied in the oxidation kinetics: time, temperature, pressure, surface preparation, surface area, concentration of inert gas in the lattice, cycling procedures in temperature, vacuum effect and high temperature vacuum oxidation. The general interpretation of many of these factors has been previously discussed. Literature The oxidation of molybdenum has not been studied critically. Although many studies have probably been made on the kinetics of the oxidation process, none has been reported in the literature available to us. The crystal structures found in the oxidation of molybdenum have been studied by Hickman and Gulbransen." Their results showed that Moo2 is the oxide which is stable in contact with the metallic substrate throughout the temperature range 300 to 700°C. As the film thickens in the low temperature range, MoO3 becomes predominant on the surface. Above 400°C, Moos is no longer observed, MoO2 being the only oxide found. Hagg and Magneli6 have shown from an X ray study that the a-phase, orthor-hombic Moo3 is stable up to 1050°C. Two other phases, ß and ß with compositions close to MoO2.90 are also obtained. The formula for the 0 phase is not given but that of the ß phase is defined as Mo9O26 The 0' phase is found to be built upon a monoclinic unit cell. A ?-phase is isolated from a preparation MoO2.75 heated for 17 hrs at 670°C. This phase is

Jan 1, 1949

By J. W. Downey, R. A. Morris, M. V. Nevitt

An experimental survey has determined the occurrence of Ti2 Ni-type phases in binary and ternary alloys of Ti, Zr, or Hf with first, second, or third long-period transition metals and also in ternary systems in which 0 is the third component. The existence of eleven previously unreported isomorphs is cited and some approximate phase boundaries are given. Lattice parameters are reported for the new phases. The periodic table relationships involved in the occurrence of the phase are discussed. A previous paper' reported the occurrence of a group of Ti2Ni-type phases (structure-type E93) containing Zr in combination with Rh, Ir, and Pt, and Hf in combination with Rh, Pd, Ir, and Pt, and cited evidence to show that all of the Zr phases and the Hf-Pd phase are not binary phases but occur only when 0 is present. More recently one of the present authors found that in the ternary systems of Ti and 0 with Cr, Mn, Fe, Co, and Ni the occurrence of the Ti2Ni-type phase could be correlated qualitatively with valency electron concentration, and that the role of 0 appeared to be that of an electron acceptor.' This paper describes the results of a broader investigation of the occurrence of Ti2Ni-type phases in binary and ternary systems containing Ti, Zr, or Hf. EXPERIMENTAL PROCEDURE Alloys were prepared by arc melting. The purity of the metals Zr, Rh, Hf, Ir, Pd, and Pt was given in the previous paper.' The additional materials used for this work were metals with a minimum purity of 99.9 pct and reagent grade ZrO2, TiO2, Cr2O3, and NiO. Chemical analysis of several alloys in each system indicated good agreement between intended compositions and cast-button compositions. For the heat treatment precautions were taken to avoid oxygen contamination. The specimens were wrapped in Mo foil and sealed in fused quartz tubes at a room temperature pressure of 1 x mm of Hg. These capsules were then annealed in a vacuum furnace at an external pressure of 5 X mm of Hg. Since the major constituent in most of the alloys studied was the brittle Ti2Ni-type phase, Debye-Scherrer patterns with sharp lines could be obtained with powder crushed from the annealed solid samples without being reannealed. Metallographic, X-ray diffraction, and density determination techniques previously described1, 2 were used. RESULTS AND DISCUSSION Zr-Rh-O, Zr-Ir-Oand Zr-Pt-O Systems-Figs. 1 through 3 show the approximate boundaries of the Ti2Ni-type phase fields at the temperatures indicated in the ternary systems Zr-Rh-O, Zr-Ir-O and Zr-Pt-0. In each isothermal section the Ti2Ni-type phase field is labeled E and the unidentified binary phase found in the previous work' is labeled ?. The dotted lines, which are not phase boundaries, correspond to the composition (Zr2 B)1-xOx. In each system the Ti2Ni-type phase field is displaced to the high-Zr side of this composition line. However, the departures from Zr2B stoichiometry for the metal components are not as high as Zr3B, as was inferred from the previous work. Lattice parameters of the Ti2Ni-type phases in the alloys shown as triangular data points in Figs. 1 through 3 are given in Table IA. The probable compositions of the Ti2Ni-type phases have been estimated from the isothermal sections. Although there are a few exceptions that probably result from uncertainties in phase boundary location and from the effect of variation of oxygen content, the generalization can be

Jan 1, 1961

By Steven J. Schatzel, Kayode M. Ajayi, Bo H. Kim, Zoheir Khademian, Gabriel S. Esterhuizen

The stability of shale gas wells drilled through current and future coal reserves can be compromised by ground deformations due to nearby longwall mining. Depending on the longwall-induced rockmass permeability, the high-pressure explosive gas from the damaged well may reach mine workings and overwhelm the mine ventilation systems. This study uses geomechanical models to estimate the rockmass permeability induced by mining. A two-panel longwall model of a deep, 341-m-cover mining site in southwestern Pennsylvania is constructed in 3DEC to explicitly model the rockmass by a discrete fracture network (DFN) technique. Stress-induced fracture apertures and permeabilities are calculated across the model and are validated against permeability measurements. A fracture flow code (FFC) is developed to use these results to predict potential inflow to the mine should a gas well breach occur. One hundred DFN realizations are simulated, and the results show that for a gas pressure of 2.4 MPa, the average of the predicted inflow rates to this deep-cover mine is 0.006 m3/ s, significantly lower than the average inflow of 0.22 m3/ s for a shallow-cover mine (145-m deep) studied in the previous work (Khademian, et al. 2021). The result can help assess the potential hazards of a shale gas well breach for mine safety and evaluate the ventilation requirements to mitigate the risk.

Jun 19, 2022

By R. O. Vernon

The Florida Peninsula has existed as a part of a much broader plateau, since at least the Early Cretaceous. This plateau, the Floridan Plateau, now consists of the present peninsula and a broad submerged shelf of equivalent size extending the length of the state and out into the Gulf of Mexico. Florida Peninsula was separated from the mainland United States by a negative area called the Suwannee Straits. To the south of this feature existed an environment similar to today?s Bahamo Banks where very pure calcium and magnesium carbonates with associated evaporites were deposited. Thus the Eocene and Oligocene contain little or no quartz sand or clay minerals except in the Panhandle west of the Suwannee Straits where some clastics were contributed by rivers from the north.

Jan 1, 1966

By Grover H. Emrich

Pennsylvania,, due to its location in the humid east, is fortunate to possess within its borders large quantities of water. Most of the State is drained by three major river systems-the Ohio, Susquehanna and Delaware. This abundant supply of surface water has been widely utilized throughout the State, but today other sources of water must be developed due to the increasing demands for water, die largest undeveloped source of water in Pennsylvania is ground water. Pennsylvania is also fortunate to possess extensive coal resources. These coal resources have contributed measurably to the development and prosperity of the States Coal and water's - two valuable resources - have been necessary for the development and industrialization of Pennsylvania, The State needs both resources but can no longer afford to develop one while adversely affecting or destroying the other, We are aware of the effect of coal mining on surface water, but coal mining can also materially affect subsurface water, This effect will according' to the local geologic conditions.

Jan 1, 1965

By B. Samanta

A quality characteristic analysed through construction of the Shewhart control chart is required to be normally distributed. In mining applications, this assumption is often violated as many quality characteristics follow skewed or lognormal distribution. In this paper, two methods were investigated using a heuristic approach for setting up the control limits for a skewed population. Based on these approaches a Mode chart, and a Weighted Variance (WV) control charts were constructed. The performance of the proposed methods was compared with the normal based Shewhart method through a case study conducted in a surface mine supplying iron ore to a steel plant. A simulation study was also conducted to evaluate the effectiveness of the proposed methods over the Shewhart method. The study revealed that the Shewhart control charts generated more out of control alarms compared with the Mode and Weighted Variance control charts for a skewed population of Fe%. The simulation results also revealed that for extremely high skewed population, the WV control chart and Mode control chart provided higher probability of coverage than the Shewhart method; although the detection rate (probability of detection) of out of control condition for these methods was slightly reduced compared with Shewhart method.

Jan 1, 2004

"This study examines the problems faced by open pit mine superintendents who make choices about how to direct their materials, either to the waste dump or to the mill. The paper explores the effects of introducing a 10% sampling error and a 0.9-times to 1.1-times sampling bias on positively skewed distributions for precious and base metals, negatively skewed distributions in the case of bulk commodities, and normal distributions as is the case for coal deposits. Parent distributions for each commodity were created on a 25 x 25 m grid using transformations of gold, iron ore, and coal data-sets, spatially based on a nonconditional Gaussian simulation. Ordinary kriging of grades for the three commodities into a 10 x 10 m grid provided the reference case against which the distributions with the sampling error and sampling bias for the commodities were compared. Imposing cut-off grades on the actual-versus-estimated scatterplots of the three commodities allowed the distributions to be classified into components of waste, dilution, ore, and lost ore. Ordinary kriging of values for each deposit type acted as the reference data-set against which the effects and influence of 10% sampling error and 0.9-times to 1.1-times sampling bias are measured in each deposit type. Indications are that the influence of error and bias is not as significant in gold deposits as it is in iron ore and coal deposits, where the introduction of small amounts of error and bias can severely affect the deposit value.IntroductionThe effects of poor sampling and the financial implications for mining companies, traders in mineral assets, and sellers of metal as dore or commodities is documented in a number of studies, the most notable of which is that by Carasco (2004). He examined the financial impact of poor sampling practices in the Chilean copper industry and found that finacial losses due to poor sampling amounted to hundreds of millions of dollars over the life of a mining operation. Holmes (2004) examined the effects of correct sampling and measurement as the foundations of metallurgical balances, and found that revenues from the sales of large iron ore shipments may be profoundly affected by poor sampling practices. In South Africa the way in which sampling of in situ gold-bearing reefs affects the mine call factor has been an ongoing study since the disparity between the estimation of gold in the reef and the actual gold bullion produced was noted by early investigators such as Beringer (1938), Jackson (1946), Sichel (1947), Harrison (1952), and a number of others."

Jan 1, 2017

By D. E. Fogelson

In a factorial experiment, blasting caps were detonated in three sizes of shotholes in mortar with three types of stemming--dry sand, wet sand, and hydrostone. Free-surface displacement pulses were recorded with a capacitive-displacement gage at a distance of 15 inches. The effects of decoupling and the type of stemming on the amplitude and the duration of the displacement pulse were determined. Both the amplitude and the duration of the displacement pulse were significantly decreased by increasing the decoupling, but they were little affected by the type of stemming.

Jan 1, 1965

By C. Kasatuka

Globalization creates investment opportunities for enterprises around the world. Attracting foreign investment has been a key challenge for economic growth in developing countries. Corruption, political instability, armed conflict, and other internal problems affect foreign direct investment (FDI) inflows negatively. A framework of criteria provides a basis for comparing non-commercial risk (NCR) among twenty-three mineral economies. Countries competing for foreign direct investment inflows are ranked from least to most risky. This study compares Inward FDI Performance Index (IND) with NCR ratings in developing countries and shows that risk is increasingly mitigated by means of appropriately structured insurance. Given the option for countries with similar mineral potential, investors will generally invest in the country that offers lower non-commercial risk. Keywords: foreign direct investment, non-commercial risk, developing countries.

Jan 1, 2006

By D Luppnow, H Rourke

Recent disasters such as the failure of the Mount Polley tailings embankment remind us of the risks that tailings facilities pose. It is widely recognised that dam-break assessments are a vital tool in identifying the consequences of the failure of a facility, which in turn can be used to develop emergency action plans. A typical assessment includes an estimation of breach parameters and outflow volume, followed by the preparation of an inundation map to illustrate potential flow extents and downstream impacts. This paper focuses on the estimation of outflow volumes, which is an area that the authors feel can be improved. Presently, many types of analyses assume that the volume of tailings released is only a function of the storage volume and dam height. After a review of several documented tailings failures, it has been found that the extent and depth of the supernatant pond needs to be considered as it is just as important, if not more so, as the storage volume and dam height. Tailings facilities with excess water storage have a higher risk of failure as they are more susceptible to overtopping, piping and liquefaction failures. In addition, they pose greater failure consequences as the saturated conditions will lead to more material being mobilised.This paper has reviewed available information on a number of tailings dam failures and proposes an alternative estimation of potential tailings release volumes as a function of supernatant water stored on the facility for use in dam-break analyses. In a broader sense, the paper seeks to shift the current risk paradigm from tailings dam heights to volumes of water stored and provides a basis for continuing research and discussion.CITATION:Rourke, H and Luppnow, D, 2015. The risks of excess water on tailings facilities and its application to dam-break studies, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 225–230 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By C. Kasatuka

Globalization creates investment opportunities for enterprises around the world. Attracting foreign investment has been a key challenge for economic growth in developing countries. Corruption, political instability, armed conflict, and other internal problems affect foreign direct investment (FDI) inflows negatively. A framework of criteria provides a basis for comparing non-commercial risk (NCR) among twenty-three mineral economies. Countries competing for foreign direct investment inflows are ranked from least to most risky. This study compares Inward FDI Performance Index (IND) with NCR ratings in developing countries and shows that risk is increasingly mitigated by means of appropriately structured insurance. Given the option for countries with similar mineral potential, investors will generally invest in the country that offers lower non-commercial risk. Keywords: foreign direct investment, non-commercial risk, developing countries.

Jan 1, 2006

By A. Faison Dixon

In India the production of mica, which in other countries is of very minor importance, is one of the staple, long established industries, and ranks high in the statistics of mineral products. Nearly two-thirds of the mica of commerce comes from India. The Indians have used mica for glazing and decorative purposes through many centuries. About 14,000 men are employed in and about the mines, and the indigenous and primitive mode of mining is still followed; but, by reason of the exhaustion of the surface supply hitherto won without intelligence or capital, it will not be many years before the present interesting and casual methods will be replaced by a less archaic and more profitable system. India on the whole has little mineral wealth, but the unique resources of its mica-fields, cheap labor, and favorable natural conditions render it unlikely that any other country can ever more than temporarily contest her leadership in the production of this one minor but essential mineral. Mica plays a small but indispensable rôle in a variety of fields of dissimilar application. Its use and value depend upon characteristics which different kinds of mica have in varying degrees, each kind being adapted to its own special purpose. Its well-known characteristics of transparency, flexibility, elasticity, toughness, high dialectric strength, perfect flatness, ease of splitting into thin films, ability to stand high heat and sudden changes in temperature, give it value in many industries. No other substance, natural or artificial, has the same combination of qualities. The oldest use of mica is in glazing. By reason of the improvements in annealing glass, this is not now of great importance, but mica is still employed for the covers of ikon images in Russian churches, the windows of anthracite stoves, compass

Jan 1, 1914

By Jan K. Wolski

This paper presents a simple method for determining air temperature gradients along a tunnel with time-dependent intake air properties. The variable intake air properties may be the flow direction and rate, air temperature and humidity, and the carbon dioxide content. The transient intake air properties are simulated by a series of steady intake air conditions, using a superposition method. The mathematical model was verified by reduced-scale experiments in the Waldo mine. The method may be usefull in conditions where the computation speed is more important than the precision of the results.

Jan 1, 1995

By G. L. Fisher, R. H. Geils

The effect of small amounts of columbium (<0.01 to 0.10 pct) on the ?-a transformation occurring during the continuous cooling of a low carbon Ni-Cu steel was investigated. Dilatometer specimens were aus-tenitized at 950" and 1068?C and cooled at 17? and 375 C° per min. Columbium caused a marked depression in the ?-a transformation temperature except when cooling at the slower rate from 950°C. The effec of columbium on the transformation temperature was greater the higher the austenitizing temperature and rate of cooling. A maximum depression of 92 C" was observed. Metallographic examination of specimens of <0.01 and 0.07pct Cb steels heated at 1200°C for 1 hr and cooled at various rates showed that columbium had a major effect on the ferrite morphology. The fer rite in the columbium -free steel remained equiaxed at cooling rates as high as 440 C? per min while the columbium-bearing steel exhibited mixed structures o equiaxed and bainitic ferrite at cooling rates as low as 130 C° per min. The ? grain boundaries in the columbium -free steel provided the ferrite nucleation sites in rapidly cooled specimens. There was a complete absence of nucleation at these sites in the colum bium-bearing steel. It is concluded that columbium depresses the transformation temperature by suppressing ferrite nucleation at the austenite grain bound-aries. In this respect the effects of columbium are analogous to those of boron in low C-Mo steels. It is well known that small columbium additions can substantially strengthen plain carbon steels. As little as 0.02 pct Cb can increase the yield strength of mild steels by 10,000 psi.1 A fine precipitate of CbC has been observed in columbium-bearing steels2 and is generally thought to be responsible for the strengthening. Little attention has been devoted to the effect of columbium on the ?-a transformation. Webster and woodhead3 have studied the effect of columbium on the isothermal proeutectoid ferrite reaction in mild steels. They found similar transformation behavior in steels both with and without columbium additions. However, as the austenitizing temperature increased, the incubation time for the start of the ferrite transformation became longer in the columbium-containing steel. Morrison1 found that the addition of 0.03 pct Cb to a C-Mn steel lowered the transformation temperature by 50 C° during cooling from 1200°C at a rate of 80 C" per min. The strengthening effect of columbium has recently been utilized in an age-hardenable, low-alloy steel containing copper and nickel.4 A small amount of columbium has a substantial effect on the as-rolled strength of this steel. By increasing the columbium level from <0.01 to 0.13 pct the as-rolled yield strength is increased by 15,000 psi. Columbium also significantly lowers the ?-to-a transformation temperature of this steel during continuous cooling from the austenitizing temperature. Because of the low carbon level in this steel (0.05 pct max), it is almost entirely ferritic. Thus, it offers the opportunity of studying the effect of small columbium additions on the proeutectoid ferrite reaction. Of particular interest in this study was the reason for the marked lowering of the transformation temperature by columbium during continuous cooling. EXPERIMENTAL PROCEDURE Materials. The compositions of the steels used in this investigation are shown in Table I. The steels were 30-lb air induction melts. They were forged to 4 by 8 by 1 in. plate at 1230°C, air cooled, and then reheated to 1230°C and cross-rolled in two passes to in. plates. Dilatometry. A Leitz Bollenrath dilatometer was used to record the transformation during continuous cooling from two different austenitizing temperatures. The dilatometer specimens were + in. in diam and 2 in. long. Oxidation and decarburization of the specimens was prevented by maintaining a small positive pressure of dry argon in the dilatometer furnace and by plating the specimens with 1 mil of Cu. For the lowest cooling rate, 17 C" per min, the temperature of the specimen was measured with a Pt-Pt 10 pct Rh thermocouple placed in a & in. diam well in the center of the specimen. During air cooling, 375 C° per min, this method of measuring the temperature interfered with the operation of the dilatometer. However, it was found that the temperature of the specimen could be measured accurately by placing a thermocouple in an identical specimen in a holder adjacent to the one being used to operate the dilatometer mechanism. The dilation-temperature curves were recorded on photographic film and then converted to volume percent ferrite-vs-temper-ature curves. The cooling rates obtained with the dilatometer are shown in Table 11. Cooling rates of

Jan 1, 1970

By R. K. Dann, L. W. Roberts, R. B. Benson

The mechanical properties of 300-series stainless steels were investigated in both high-pressure hydrogen and helium environments at ambient temperatures. An auslenitic steel which is unstable with respect to formation of strain-induced a (bee) and € (hcp) mar-tensile is embrittled when plastically strained in a hydrogen environment. A stable austenitic steel is not embriltled when tested under the same conditions. The presence of hydrogen causes embrittlement at the mar-lensitic structure and a definite change in the general fracture mode from a ductile to a quasicleavage type. The embrittled martensitic facets are surrounded by a more ductile type fracture which suggests that the presence of hydrogen initiates microcracks at the martensitic structure. If a steel is unstable with respecl to fortnation of strain induced martensile, plastic deformation in a hydrogen environment will produce rapid embrittlement of a notched specimen in comparison to an unnotched one. FERRITIC and martensitic steels can be embrittled by hydrogen that has been introduced into the alloys, either by thermal or cathodic charging prior to testing.1-5 However, conflicting reports exist as to whether austenitic steels that are stable or unstable with respect to formation of strain-induced martensite can be embrittled by hydrogen.8-12 A recent investigation has shown that cathodically-charged thin foils of a stable austenitic steel can be embrittled.13 An earlier investigation of a thermally charged 18-10 stainless steel revealed a significant decrease in the ductility only at the lowest test temperature of -78°C, although strain-induced bee martensite was shown to be present in one specimen tested at ambient temperatures.&apos; When martensitic steels are tested in a hydrogen atmosphere, they are embrittled.&apos;4-&apos;7 It has been observed in this Laboratory that 304L steel, which is unstable with respect to formation of strain induced martensite, forms surface cracks when plastically strained in a high-pressure hydrogen environment. Work in progress elsewhere concurrent with this investigation has also established that 304L is embrittled when tested in a high-pressure hydrogen atmosphere." The objective of this investigation was to study the effect of a high-pressure hydrogen environment on the tensile properties of a stainless steel that contained strain-induced martensite (304L) and one that did not (310). EXPERIMENTAL TECHNIQUES Notched and unnotched cylindrical specimens were machined from 304L* and 310 rods that were heat- treated at 1000°C in argon for 1 hr followed by a water quench. The chemical analyses of these steels are given in Table I. The unnotched specimens had a reduced section diameter of 0.184 & 0.001 in., a gage length of 0.7 in., and were threaded with a 0.5-in.-diam. thread on each end. The notched specimens had a reduced section diameter of 0.260 * 0.001 in. and a 0.75-in. gage length, with a 30 pct 60 deg v-notch at the center. The notch had a maximum root radius of 0.002 in. The tensile bars were fractured in a hydrogen or helium atmosphere of 104 psi at ambient temperatures. The system used for mechanically testing the specimens is to be described in detail elsewhere.19 Several specimens of each type were tested in air using an Instron testing machine. The same yield strength and ultimate tensile strength were obtained in 104 psi helium with the above system as with the conventional testing machine. Magnetic analysis was employed to determine that there was a (bee) martensite in plastically deformed 304L and that it was not present in plastically deformed 310. The magnetic technique depended on allowing the material being studied to serve as the core between a primary and secondary coil. Thus, any change in the amount of magnetic material present between the annealed and plastically deformed steels will be indicated by corresponding changes in the induced voltage in the secondary circuit." The ratio of the output signal of a nonmagnetic stainless steel to a completely magnetic maraging steel was 2000 to I. Several unnotched 304L bars tested in hydrogen were analyzed for hydrogen by vacuum fusion analysis. There was an increase in the hydrogen content to approximately 2 ppm for the specimens tested in hydrogen, as compared to less than 1 ppm for the as-received material. Several thin sections cut from notched areas of 304L specimens tested in hydrogen and containing the fracture surface contained approximately 1.5 ppm H. The accuracy of these determinations was estimated to be ± 50 pct.

Jan 1, 1969

By R. Lingle, E. Hardin, M. Board, H. Pratt, W. Ubbes, M. Voegele, N. Barton

A 2 m. cube of jointed, Pre Cambrian biotite gneiss was subjected to uniaxial and biaxial loading at ambient and elevated temperature. The effects of different boundary conditions on the following rockmass properties were investigated: deformation modulus, joint stiffness, dynamic modulus, coefficient of thermal expansion, thermal diffusivity and conductivity, and joint permeability. Test conditions ranged between 0 and 6.9 MPa uniaxial and biaxial load, and 12° to 74°C mean block temperature. The tests were performed as part of the Office of Nuclear Waste Isolation program for evaluating site charterization test methods for measuring the hydro-thermal-mechanical properties of rock masses. The fracture flow experiments discussed in this paper were described in detail in a similar paper given to this symposium in 1981 (Voegele, 1981). DEFORMATION MODULUS Horizontal deformation measurements oriented parallel to the loading direction were made at the block surface. Several instrument types were employed: surface short-rod extensometers, bonded strain gauges, vibrating wire strain gauges and the Whittemore caliper strain gauge. Two vertical and two slant borehole extensometers measured vertical displacement. Loading history, especially during uniaxial loading, was critical to interpretation of observed deformation and fracture flow data. This important tendency has been observed in other large-scale laboratory (Bandis, 1980) and field tests (Pratt, et al., 1977). Excavation of the block resulted in minimal disturbance to the intrinsic condition of the sample. Even so, permanent, unrecovered "set" was imparted to the block beginning with the first low-stress biaxial load cycle to 3.45 MPa (Table 1). Unloading

Jan 1, 1982

By James A. Madonna

Several universities and colleges in Australia, Canada and the United States, recognized the need to establish or reorganize geoscience programs at the vocational and two-year technical levels. To accomplish this, a cooperative study with industry in one state or province from each country was initiated. These include Tasmania in Australia, British Columbia in Canada and Alaska in the United States. The objective of this work was to develop a diversified geoscience educational model at the two-year technical, vocational and continuing education level that provides the source from which any nation can draw the proper educational tools to create a new geoscience program, modernize an existing program or strengthen a weak program. More than 100 mineral industry organizations provided information regarding their specific training needs for support personnel. The data gathered have been used to identify training areas for semi-skilled, skilled and technical personnel in geochemical mineral exploration. These included geological, geochemical, environmental and computer skills. With the areas of major educational need defined for geochemical exploration, an educational field skills model was developed for the three levels of training. The international need for a study of this type was recognized as early as 1980, following numerous contacts from domestic and foreign geoscience educators regarding the structure and success of training within the University of Alaska Fairbanks Mining Extension program, located in Fairbanks. Contacts, correspondence and visits included educators from Australia, Brazil, Canada, Mozambique and the conterminous United States. The need was magnified between 1985 and 1989 at the University of Alaska Fairbanks, when an attempt failed at initiating and developing a two-year geoscience vocational-technology program leading to an Associate of Science degree.

Jan 1, 1994