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By C. K. C. K. Gupta

The rare earths in elemental form are required for a variety of scientific and technological purposes. They are not easily obtained in this form, due to the great chemical stability of the rare-earth compounds and the strong tendency of elemental metals to react with everything they come in to contact with, especially at high temperatures. Beginning in the 1950s, when sufficient quantities of separated rare earths became available, as the result of intense research and development, three processing routes were developed to accomplish the preparation of all 16 naturally occurring rare-earth elements. They are chemical reduction of the halide intermediates, the oxides and electrochemical reduction of chlorides and oxide-fluoride mixtures. Not all the processes are effective with all the rare earths. In spite of the celebrated similarity of trivalent rare earths, the physical properties of individual rare-earth elements are sufficiently different that a variety of techniques are required for their preparation. The development of reduction processes for the rare-earth metals are covered in this paper, with focus on the oxide reduction routes. The strong reliance of effective reduction processes on the fundamental science of reduction reactions is highlighted.

By J. F. T. Agapito

Significant economic benefits can result when rock mechanics is applied within a practical framework and integrated within the other engineering functions of the mine organization. This requires management support and understanding of rock mechanics as a practical tool to help attain high standards of safety, productivity and resource recovery. For such an approach, a long-term geotechnical program is needed in most operations to build an adequate data base and to ensure that design and ground control issues are handled in a cost-effective manner. This paper presents a summary of four case studies where significant economic benefits were realized with the help of rock mechanics. Although cost savings were not computed, the economic benefits are obvious and clearly impacted the mine operations favorably.

Jan 1, 1990

By James Parkes

"The proposed Baltimore Red Line light rail system includes a 3.4 mile downtown tunnel (DTT) with five underground stations. The design of the underground stations involved overcoming several challenges, including limited right-of-way, high groundwater and uplift pressures, and metamorphic rock within the station depths. An innovative design was developed to maximize the internal station space while minimizing cost. The station designs use slurry walls for temporary and permanent support and groundwater control. Depths within rock are supported with cast-in-place concrete walls, the thickness of which are minimized through the use of permanent rock anchors for support of the rock mass and slurry wall toes. Permanent tiedown anchors are used for uplift resistance, which minimizes the station depths, volume of rock excavation, and the volume of deadweight concrete. Design considerations regarding individual elements and overall integration of the slurry walls, CIP walls, and multiple anchor types are presented.INTRODUCTION The Baltimore Red Line (BRL) project is a proposed light rail transit line for the Maryland Transit Administration (MTA) that runs east to west through Baltimore City and County. The project includes the Downtown Tunnel (DTT) consisting of 3.0 miles of twin running tunnels, two portals, five underground stations, and a pedestrian tunnel, as shown in Figure 1. The tunnels have an outside diameter of 21.8 feet and are designed to be mined using pressurized face tunnel boring machines (TBMs). The stations, portals, and the pedestrian tunnel are designed as cut-and-cover structures using slurry walls (concrete diaphragm walls) for both temporary support of excavation (SOE) and permanent structural walls. The dimensions of the five underground stations are summarized in Table 1. Design challenges included limited right-of-way (ROW), challenging soils conditions, strong metamorphic rock within the station depths, and high groundwater conditions. The final station designs included innovative use of slurry walls, tieback anchors, rock anchors, and tiedown anchors."

Jan 1, 2016

By B. Mishra

This paper presents a rock mechanics investigation of the time-dependent behavior of the rock immediately surrounding the excavation in a hypothetical one-entry coal mine based on the geology of the Illinois coalfields Research in the area of time-dependency is almost nonexistent and, therefore, this research was performed to make inroads into this neglected research area. Numerical analysis of a typical one-entry coal mine in an Illinois basin was performed using the commercial finite difference program FLAC3D. The immediate roof of the coal entry was assumed to be a shale formation. Shale in other formations has shown a tendency to creep with time. Therefore, in this study the authors modeled the shale in the roof using time-dependent characteristics. The input properties were taken from laboratory creep tests performed on shale. Model runs were performed at different stages, mimicking the progressive excavation of the entry. The model results showed that stresses in the roof attained the limit of yielding. Using Mohr-Coulomb failure criteria, potential zones of failure were also predicted. The results showed that the current computational capacities are sufficient to explore this previously uncharted territory of ground control.

Mar 1, 2014

By C. T. Holland

Coal mining has been an important industry in the Appalachian area for many years. This is particularly true in the northern part of the area, namely, in Pennsylvania, West Virginia, and Ohio. Also, in the south a great deal of mining activity has been carried on in Alabama, Kentucky, and southwest Virginia. Some of the by-products of this activity has been the production of mineralized water from the mines in copious quantitites. The southern Appalachians have been somewhat more fortunate in that the water there has had a considerable amount of alkalinity in it, which has to a large extent eliminated some of the more undesirable aspects of mine drainage. Northern Appalachia, including central and western Pennsylvania, the Monongahela basin in West Virginia, and the Appalachian area in eastern Ohio have not been so fortunate in that coals in those areas and the top and bottom rock have, in many cases, shown considerable quantities of pyrite, and the water does not carry the carbonates found farther south.

Jan 1, 1969

By Brij M. Moudgil

Flotation of fine and coarse coal after multistage addition of the frother was found to yield coal fractions with significantly lower ash content as compared to the feed. It was observed that the lowest ash content, specific gravity and reactivity of coal was associated with finer size fractions. Ignition and combustion characteristics of different coal fractions were evaluated using a differential thermal analyzer (DTA) with calorimeter attachment. It is suggested that in the ignition stage, the removal of mineral matter affects the reactivity through the physical changes brought about by the ash removal. In the char combustion stage the mineral matter seems to influence the reactivity through the catalytic activity of surface concentrations of metal ions, ratio of combustible/incombustible material, internal pore structure and roughness.

Jan 1, 1984

By Walter von der Linden

On April 14, 1975, Consolidation Coal Company began to operate a longwall face in their Shoemaker Mine using shield supports. This was the first time that shield supports were used in the United States (1) 1/. Shortly thereafter, Kaiser Steel Corporation started a shield longwall face at their York Canyon Mine (2). From October 1975 through May 1976, three more longwall faces were commissioned in mines located in south-western Pennsylvania and northern West Virginia. In June 1976, four installations had completed their first panel and two installations had completed the subsequent move to the second panel where coal production is now well under way. During this time (April 75 to June 76) the total number of shield support face operating months, including moving time, was 40 and the combined face advance was approx. 17, 000 feet (5200 m) with face lengths varying from 450 - 550 feet (137 - 168 m). While the shield support experience in the U.S. is still limited on the basis of time and mining parameters, the operating results of all faces have been very satisfactory. New record 24 hr production figures were set and - far more important - long term production figures could be sustained on an impressively high level even when taking face moving time into account. The purpose of this paper is to review the performance of shield type supports in the U.S. and to assess their value as longwall supports for U.S. underground mining conditions with regard to roof control, maintenance, operator convenience, safety and productivity.

Jan 1, 1976

By Russell L. Cook

Stringent environmental regulations, which have limited the use of sludge ponds, coupled with the economic incentive to clean more 'coal or to add fine coal cleaning additions to existing preparation plants have increased the use of static thickeners in preparation plants. The Lamella Gravity Settler, sometimes de signated Lamella Thickener, is a shallow depth sedimentation device which has been applied in a variety of industrial process and wastewater control projects in place of the conventional raked thickeners. This paper presents the theory and design of the La-mella Thickener, as well as describing the operating results from several full scale installations in a variety of Appalachian preparation plants.

Jan 1, 1977

By Zoë Dugdale, Gerald Poplin, Tim Bauerle

"Fatigue presents several challenges for the mining industry. Depending on the specific occupation, daily work or operational setup on any given mine site, mining jobs can have a fair amount of labor-intensive tasks mixed with monotonous and repetitive duties. Combined with the long working hours and shift-work schedules of mining work, the prevalence of fatigue in mine workers may seem rather unsurprising.Mining is certainly not alone in facing the challenge of addressing worker fatigue. Indeed, many of the characteristics above mirror the similarities of fatigue in other industries, such as health care, aviation and security. To the extent that fatigue in mining acts like fatigue in any other industry, then any fatigue management applications, trainings, or interventions in existence can be borrowed from other industries and applied to mining in a cookie-cutter approach. However, some have argued that mining in particular is especially susceptible to increases in the prevalence of fatigue beyond the characteristics listed above due to the multifaceted combination of factors in mining environments associated with fatigue: dim lighting; limited visual acuity; hot temperatures; loud noise; highly repetitive, sustained, and monotonous tasks; shiftwork; long work hours; long commute times due to mine site remoteness; early morning awakenings; and generally poor sleep habits (Canadian Centre for Occupational Health and Safety, 2012; Legault, 2011). Legault (2011) in particular argues that it is the combination of these factors simultaneously that can make mineworkers particularly susceptible to sleep deprivation and fatigue in comparison to other industries where these factors are often not present all together. If fatigue looks and acts different in mining, as others have argued, more research is needed to determine if, how, and why worker fatigue might need to be managed differently in mining.While the burden of fatigue on the mining population has not yet been evaluated thoroughly, methods and measures of fatigue management remain a popular point of discussion. Many commercial suppliers and consultancy groups have begun to develop technologically based fatigue monitoring systems (McMillian, 2013). Some technologies can monitor vehicle operators for indicators of wakefulness, such as percent eyelid"

Jan 3, 2018

By Gary D. Aho

The United States on a daily basis no consumes about 15MM barrels (2.38 x 106m3) of oil; 5MM (0.79 x 106 m3) of this is imported. This compares tai a daily consumption of 18MM (2.86 x 106 m3) in 1980 when we imported 8MM (1.27 x 106 m3). We are producing the 10MM barrels (1.59 x 106 m3 ) of conventional oil at home from what amounts to just 2% of our domestic energy reserves. Nearly 90% of our total domestic energy reserves occurs in solid forms such as coal, oil shale, and tar sands; this is more than enough to meet our needs for the next 100 years. Worldwide, oil shale is second only to coal as a potential source of energy and the U.S. has approximately one-half of the world oil shale reserves which average over 25 gallons per ton (10.43 x 10-2 L/kg). Since the United States has immense oil shale resources, including some of the richest in the world, and since oil shale produces a superior transportation fuel, it would seem logical that the U.S. would be prudently developing this domestic resource. Unfortunately, despite over 50 years of research and a number of false starts, there is not a commercial shale oil industry in place today. There are a number of recurring roadblocks which have hindered private industry's efforts to develop oil shale and we will look at some of these.

Jan 1, 1983

By Olav Moklebust

The R-N Process is an outgrowth of the development by the National Lead Company's Norwegian subsidiary Titania A/S, of a process for producing metallic iron and a high titanium content co-product from ilmenite. Development of the process for the treatment of iron ores was continued as a joint project of the Republic Steel Corporation and the National Lead Company in 1953. More recently in July, 1957, the R-N Corporation was created by these two companies to undertake the commercial promotion of the results of this joint project. This paper has been prepared with the permission and encouragement of these three companies. The R-N process has as its objective the making of metallic iron from iron ores or iron ore concentrates. The general principles of the process have already been disclosed in technical papers and patents. In general the process comprises the following steps: 1. Iron oxide in crushed natural iron ores or iron ore concentrates is reduced to about 95% metallic iron, without fusion in a rotary kiln in the presence of solid carbonaceous fuel,*such as, coke or char, limestone and combustible gases. 2. The kiln discharge, consisting of metallized ore, coke, lime and coke ashes, is cooled. The excess coke is regenerated and recycled to the kiln feed.

Jan 1, 1959

By J. R. Klaehn, M. Shi, T. E. Lister, L. A. Diaz, J. S. McNally

Since 2019, approximately two dozen international battery recycling companies have been operating at the commercial or pilot scale [1]. However, current process capacity does not exceed 100,000 tons of end-of-life (EOL) lithium-ion batteries (LIB) per year, and the current recycling rate is only about 5% in North America [2-3]. Recycling metals from EOL LIBs is not only essential to waste minimization and environmental stewardship, but also a source of critical materials, which can contribute towards supply chain stabilization. LIB recycling can be roughly divided into three categories: direct recycling, pyrometallurgy, and hydrometallurgy. Direct recycling seeks to retain as much of the manufactured effort with minimum chemical processing [4]. The evolution of battery designs and chemical compositions are challenges to this approach [5-6]. Pyrometallurgical processes are robust and flexible allowing a broad spectrum of batteries with minimum pre-processing requirements. Some of the matrix issues are solved through combustion of some constituents. Smelting is strongly tied to fossil energy and air emissions are a concern. In addition, pyrometallurgical processes are not stand alone, as hydrometallurgical refining normally required to separate and recover the metals of interest (Co, Ni, and Cu) from the produced alloy and Li from the slag [7]. Hydrometallurgical processes can be highly selective and efficient in recovering high purity materials [8]. In general, hydrometallurgical processes are considered cleaner and less costly than high temperature processes [4,9-10]. Extensive chemical consumption and waste generation significantly increase the operating costs and overall environmental impact of the hydrometallurgical processes [11]. Leaching of metals from LIBs is dominated by the mixture of sulfuric acid (1 to 4 M H2SO4) and hydrogen peroxide (1 to 15 wt.% H2O2) [10]. Although organic acids have been tested as lower environmental impact alternatives, the reported pulp density operations are low < 60 g/L [10-11]. For the H2SO4/H2O2 leachates, high leaching efficiencies >90% are reported for Co, Ni, Mn, and Li from cathode materials at temperatures over 40 ⁰C and pulp densities between 30 to 200 g/L [9-10]. H2O2 acts as reducing agent to convert Co+3 and Mn+4 into their soluble forms, Co+2 and Mn+2 [12]. Despite the claims of H2O2 being a clean reducing agent [13], production of H2O2 has significant environmental impacts as determined by life-cycle analyses [13-14]. Moreover, the costs and risks associated with H2O2 transportation and storage cannot be ignored [15].

Mar 2, 2022

By James A. Deane

Strip mine reclamation Fs the process of restoring the land affected by the mining process to its most productive use. This can be timber production, pasture, crop land, wildlife and/or recreational use. The mining companies must determine, through the advice of their technicians, what the most advantageous use of the land will be. If the Company does not own the surface, the owner or owners must be contacted to determine their desires as to how the land should be reclaimed. Many times, in making the plans to restore an area with vegetative cover, the watershed and the quality of the water in the area is overlooked. The water itself must be an integral part of the reclamation plan. Many lakes and/or pits can be created with proper planning. In areas in the Midwest, where lakes are a scarcity, these strip mine lakes can become storage reservoirs for large amounts of water, They can help control runoff and low flow augmentation. The strip mining operation will affect the watershed regardless of whether a reclamation plan in made or not. It is up to the reclamation technician to see that the plan benefits the watershed instead of affecting it adversely. This can be done during the operation by intercepting the water before Pt enters the active pit. Diversion ditches above the highwall will handle the runoff water from the watershed. Water that does gain entry into the pit should be removed as quickly as possible. If the rules and regulations adopted by the Ohio River Valley Sanitation Commission in Resolution 5-60 are followed, water encountered during the operation can be handled with little or no adverse effect to the receiving watershed.

Jan 1, 1965

By T. W. Beck

Drilling into coal mine roof strata to install roof bolts has the potential to release substantial quantities of respirable dust. Due to the proximity of drill holes to the breathing zone of roof bolting personnel, dust escaping the holes and avoiding capture by the dust collection system pose a potential respiratory health risk. Controls are available to complement the typical dry vacuum collection system and minimize harmful exposures during the initial phase of drilling. This paper examines the use of a bit sleeve in combination with a dusthog- type bit to improve dust extraction during the critical initial phase of drilling. A twistedbody drill bit is also evaluated to determine the quantity of dust liberated in comparison with the dust-hog-type bit. Based on the results of our laboratory tests, the bit sleeve may reduce dust emissions by one-half during the initial phase of drilling before the drill bit is fully enclosed by the drill hole. Because collaring is responsible for the largest dust liberations, overall dust emission can also be substantially reduced. The use of a twistedbody bit has minimal improvement on dust capture compared with the commonly used dust-hog-type bit.

Jan 1, 2014

By R. S. Hearon

The image of the open-pit miner in the eyes or the Environmentalist has never been very outstanding. The phosphate industry, whose history in Florida reaches back to the late 1800&apos;s, can-not be credited until recently with a large number or accomplishments in terms of protection or the environment to change this image. This lack of action was not deliberate or in opposition with the desires of the public. In the formative years, there was little or no public and the companies found it necessary to build towns to house their employees and their families, towns which remained in existence until the late 50&apos;s and early 60&apos;s or formed the core of present large communities. Neither these pioneers nor most subsequent resource developers considered themselves un-thinking spoilers, nor were they so regarded by their contemporaries. Instead, they acted in a manner consistent with their environmental circumstances and intellectual heritage. Early Americans did make mistakes in using the land but the mistakes became apparent only in the opinion of later generations. Over the past five to ten years, there has been a new self-awareness in the industry with regard to environmental responsibilities brought about, in part by a continuing onslaught of new regulations with jurisdiction over our activities. Part of the new regulations are aimed at industries as a whole while many, particularly state regulations, pertain specifically to the phosphate mining industry. Why all the new regulations? The reasons are encased in a complex web of activity but stem primarily from a new public awareness of its environment. More and more of our youth have become interested in the environmental science areas such as biology and ecology. The tremendous growth rate in both the population and industry has made personal issues out of subjects such as atmospheric inversions and water shortages which previously were abstract concepts. The State has grown from a population of 1,500,000 in 1930 to approximately 9,000,000 people today. This personal impact and general lack of knowledge on the part of the public concerning economics has resulted in big business no longer being held in awe, often in contempt and generally in suspicion where environmental concerns are encountered.

Jan 1, 1978

By Albert Hofstra, Joel Leventhal

The gray, dark gray and black colors of the sediments and the presence of pyrite in the Carlin, Jerritt Canyon, Horse Canyon, Betze, and Gold Acres sediment-hosted disseminated gold (SHDG) deposits indicate that these rocks are not oxidized with respect to carbon and iron sulfide. Both ore and non-ore host rocks generally are dark colored. Analyses for noncarbonate carbon (usually called organic carbon) in samples from SHDG deposits and related unmineralized rocks indicate that these rocks contain from a few tenths to a few percent carbon. We use the term noncarbonate carbon because, strictly speaking, organic carbon denotes carbon that is bound to hydrogen. However, the carbon present in SHDG deposits and related rocks has very little hydrogen chemically bound to it. Rocks with less than 2% organic carbon are usually gray in color. The dark colors in our samples are due to the relatively high temperatures that these rocks have experienced relative to organic matter maturation. We confirm the results of Nelson et al. (1982) that previous reports (for example, Radtke and Scheiner, 1970) were incorrect in reporting significant amounts of humic acids, extractable hydrocarbons (bitumen) or "carbonaceous" material. We believe these reports had problems with contamination or misdirected emphasis. Our samples consisted of unweathered rocks, collected mainly from mine cuts (benches, trenches, cores) and put into glass containers or wrapped in aluminum foil to avoid contamination. Only a few samples were collected from natural outcrops. We were careful to avoid samples in proximity to blast holes that were packed with ammonium nitrate and diesel fuel ("ANFO"). Contamination by ANFO may explain some of the previous reports of hydrocarbons, pyrobitumens, humic acids and anomalous nitrogen. When we were collecting samples, it was apparent that in addition to lithologic and color differences, the surface appearance of the rocks was distinguishable: "preg robbing" material that had a sooty surface; "graphitic" rock with a shiny surface; and more ordinary rocks that had a flat gray or black appearance. [Preg robbing is a term for ores that adsorb gold from the milling circuit; the graphitic material had not been x-rayed to actually identify graphite.] We hoped that laboratory study of these samples would show some fundamental differences that we could relate to ore genesis. Even though these sample types appeared different in the field, we could not distinguish any differences in thermal maturity (see below). Normal petroleum/organic geochemical laboratory procedures (solvent extraction, Rock-eval, pyrolysis-gas chromatography) failed to yield much information because the carbon was over-mature relative to oil and gas generation. Rock-eval results show less than 20 (± 20) mg of pyrolizable hydrocarbons per gram organic carbon (and an indeterminate Tmax) indicating that the organic matter in these deposits is burned-out relative to petroleum generation [with an H/C (atomic) ratio of less than 0.41. Because of the non-definitive results from standard organic geochemical methods, x-ray diffraction (XRD) and Raman spectroscopy were used to characterize the carbon. Prior to XRD, samples were treated with HCl and HF acids (1) to remove quartz that has a peak near 26° [20] at the position of the 002 peak of graphite and (2) to concentrate the carbon to a level detectable by XRD. The residue was put on a colodion mount and analyzed by XRD. The XRD analyses yielded a broad peak at 26° [20]. The shape of this peak indicates that the carbon is more thermally mature than anthracite rank coal but less mature than crystallized graphite. Based on XRD results from the literature (Landis, 1971) that are calibrated to metamorphic facies, results from our samples correspond to pumpellyite-actinolite to lowermost greenschist facies conditions, probably

Jan 1, 1990

By Frederick B. Henderson

The US Environmental Protection Agency (EPA) has tried many regional and laboratory efforts to develop measurement and monitoring techniques using environmental remote sensing technologies. In 1997, the agency established the Advanced Measurement Initiative (AMI): This is a eadquarters-level program, operating under the auspices of the EPA Office of Research and Development. The program is one result of the April 30,1996 White House Conference on Advanced Monitoring of the Environment. The EPA was encouraged to work with other federal agencies to leverage its remote sensing capabilities and use them to improve the efficiency, cost-effectiveness and flexibility of environmental measurement and monitoring for regulatory compliance and reinvention. During the fall of 1996, the EPA and the Department of Energy developed an interagency effort to broaden the use of governmental technologies for environmental measurement and monitoring. In addition, the EPA and the National Aeronautics and Space Administration (NASA) conducted joint workshops on the use of NASA remote sensing and other technologies for water quality and pollution applications. In the meantime, the EPA proceeded with an industry-proposed workshop to explore ways to cooperatively examine new research and to develop commercial remote sensing systems. It also examined how these systems might become accepted by the EPA in the regulatory and compliance processes. In particular, industry was interested in where new remote sensing capabilities might fit in with EPA&apos;s efforts at regulatory reinvention. Historically, the mining and petroleum industries have been reluctant to experiment with or use environmental remote sensing. They were concerned with the unknown liability from potential discovery of previously unknown environmental problems. Moreover, resource industries have been reluctant to use remote sensing for environmental applications where the EPA did not accept such data or information as part of the compliance process. Acceptance by the EPA of these advanced measurement and monitoring technologies (AMMT) will be a major reason for industry&apos;s increasedd use of remote sensing in environmental "applications for regulatory compliance. In July 1997, the EPA Office of Research and Development hosted at the Colorado School of Mines a stakeholders workshop on the AMI program and industry-government collaboration. The workshop&apos;s aim was to demonstrate the usefulness of AMMT technologies for environmental applications. Stakeholders included the mining and petroleum industries; environmental services companies; state environmental agencies and local governments; remote-sensing, value-added companies and data suppliers. The workshop used specific technologies and applications as a way to develop collaborative demonstration projects for several AMMT technologies covering different environmental problems. The workshop focused on the use of highly sensitive hyperspectral (very narrow spectral bands), geographic information systems and surface mapping to identify active acid-producing mine dumps and wastes from benign wastes at Leadville, CO. NASA&apos;s advance infrared imaging spectrometer (AVIRIS) was the instrument used. It was developed at California Technology&apos;s Jet Propulsion Laboratory. The EPA, the US Bureau of Land Managment (BLM), the US Geological Survey and several environmental service contractors sponsored the overflight and data evaluation. The AVIRIS study demonstrated reliability (95% correct surface mineral identification) and cost-effectiveness of this technology to accurately map and discriminate active acid-producing mine wastes from benign wastes. It could also predict which streams would be effected by acid and toxic mineral drainage. The BLM&apos;said that the AVIRIS overflight could save it $500,000 a year in surface sampling costs at Leadville. The AMI workshop further outlined five 1997 funded AMI projects of potential interest to the mining industry. They were: ? Mine waste characterization using remote sensing methodologies at Asarco&apos;s Ray Mine in Arizona. ? Predictive emissions development and testing in

Jan 1, 1997

By George J. Thompson

Almost all persons connected with mining industry have had an exasperating experience like the following: &apos;On a cold and frosty morning in mid-January, you find yourself quite happy with the world. Production is up and the mine has been running smoothly. All at once the radio cracks up your tranquility -- &apos;so and so&apos; piece of equip¬ment has broken its &apos;whatzit&apos;. Now the iron is in the fire, and things have to be fixed quick.!&apos; This can be a major failure which will bring the whole operation to a grinding halt or just one of the numerous maintenance headaches on an auxiliary piece of equipment. After one has experienced a major or minor catastrophe, he has to wonder whether some other methods with respect to design and maintenance would help prevent these unexpected calamities. The objective of this paper is to gain an insight into the charac¬teristics of steel at cold temperatures so that better decisions can be made with respect to maintenance and repair of mining equipment. Most machinery and their structures are exposed to cold temperatures. Even in locations as far south as Alabama and Arizona, brief periods of cold in winter months can adversely affect the ability of mach¬ines to do their work. To understand the background of cold temperature brittle fracture, jet us examine its basic elements. First, when steel gets cold, it gets brittle. This is best described by Figure 1. This graph shows a typical stress/strain curve of a mild or medium grade steel at room temperature. Stress is defined simply as the amount of force acting on one square inch of

Jan 1, 1972

By C. J. Milam

Oil shale may not produce the same excitement of the gold rush days, but presently there is an "oil shale fever" among mining men. Such exotic equipment as 800-ton haul units, 75 ft. boring machines, and huge fully automatic multi-purpose jumbo drill units are only a few of the topics of conversation in the oil shale groups. I am dreaming, perhaps, but this type of exotic thinking will exuberate the advancement in mining technology and will only be tempered by the practicality and the availability of today&apos;s equipment.

Jan 1, 1975

By Erwin K. Roesner

The difficulties encountered while sinking deep shafts for Potash Mines in southern Saskatchewan have been the subject of several papers in the past. Geological and hydrological conditions of the strata overlying the potash deposits require special techniques for ground and water control during shaft sinking. The easily soluble potash ore requires the lining of these shafts to be virtually watertight to assure long term and safe operation. This paper describes the construction of the most recently completed potash shaft for the Potash Corporation of Saskatchewan. The shaft was designed and constructed by Thyssen Mining Construction of Canada Ltd. and it is located near Lanigan, approximately 110 km east of Saskatoon.

Jan 1, 1980