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By Andrea Biagi, Elisa Comis, Gianluca Bella, Enrico De Panicis, Guido Barbieri, Matteo Giani

The Sotra Link Project is a major infrastructure project in Norway involving the design, construction, financing and maintenance of several underground and surface structures between Sotra island and the city of Bergen, among them 23 tunnel portals, 12.5 km of tunnels and a 900 m long suspension bridge. This paper describes the benefits in applying a Building Information Modelling (BIM) approach to tunnelling, from Early Design to the Detail Design Phase. The BIM application to the Sotra Link Project resulted in several improvements, such as efficient handling of clashes and inconsistencies, deeper understanding of effective design choices (reduction of errors), more efficient communication between designers, enhanced control of project quantities and costs. The advantages of the BIM approach during the ongoing Construction Phase are also explained.

Jun 23, 2024

By Nicholas C. Lias

Quartz crystals are the raw material from which are made the crystal units utilized in filters and oscillators so vital to the performance of all long distance communications systems. These devices act as the heart of equipment that permits a single telephone cable to carry hundreds of conversations simultaneously. Quartz crystals are of value in communications because of this piezoelectric nature, that is when an electric signal is applied to the quartz, there is a resulting mechanical motion and conversely, a mechanical stress results in an electrical output signal. A plate cut from a quartz crystal will oscillate at some specific frequency, which is determined by the physical dimension of the plate. During the early stages of telephony, all quartz plates were cut from natural quartz, which was imported mainly from Brazil. Since the source of this important raw material was based upon a foreign supply which is located at a great distance from the user and could be vulnerable in time of a national emergent, it became necessary to maintain a large inventory of this strategic material. Also due to the considerable cost of natural crystals of a size and quality suitable for Bell System use, an investigation was made by Bell Laboratories into the possibility of developing a substitute material. The effort was successful and led to a joint development program between Bell Laboratories and Western Electric. This program brought about the design of manufacturing facilities capable of producing large quantities of cultured quartz at Western's Merrimack Valley Works, No. Andover, Massachusetts.

Jan 1, 1973

By S. S. Hsieh

As part of a program to address long-term needs for ensuring adequate supplies of domestic phosphate raw materials, the Tennessee Valley Authority (TVA) has conducted considerable research on dolomitic phosphate rock beneficiation. The discovery that alkyl diphosphonic acids act as phosphate mineral depressants led to the development of several processes involving a carbonate flotation step for the effective beneficiation of these problem ores. Most recently, a partial de-oiling process in which the reagent consumption is greatly reduced has been developed. The reduction is achieved because part of the initial feed is beneficiated without passing through the separate carbonate flotation step. Using this method, a phosphate product containing 30.6-30.9% P2O5 and 0.7-0.8% MgO was obtained from a Florida dolomitic phosphate pebble which contained about 23% P2O5 and 2.0% MgO. The P2O5 recovery was 80.8-86.5%.

Jan 1, 1989

By J. H. Mackey

"Where can I obtain a reclamation bond today?" "Who is writing your bonds?" These questions are common and heard frequently. The fact that the Society of Mining Engineers has determined that two of the five environmental topics reviewed at the 1989 Annual Meeting relate to reclamation bonding indicates to me that those who are involved in the coal industry, no matter what capacity, remain very cognizant of the reclamation bonding dilemma.

Jan 1, 1989

By T. Luterbach, V. T. McLemore

"Trace element analysis of placer gold can be used as a valuable exploration tool in order to determine the original deposit source and locating lode gold deposits. Placer gold collected from multiple districts in New Mexico and Alaska, coupled with a broad database of previously analyzed placer gold samples indicate correlations between chemical signatures (especially gold, silver, and copper) and type of deposits (i.e., Au-rich copper porphyry deposits, Au porphyry deposits, and epithermal deposits). By completing a chemical analysis and determining the particle morphology of placer gold collected from these districts using an electron microprobe, patterns in the chemical signatures from each location can be used to examine chemical variability (1) within the individual placer gold particles, (2) within the same district and (3) among different districts. INTRODUCTION Although there are numerous past studies on the chemical composition of placer gold by Newberry et al. (1997), Melchiorre (2001, 2009), Townley et al. (2003), and McLemore et al. (2014), the gold analyzed tends to be collected from one or few specific districts. Rarely do those studies compare compositional results to additional districts, or elaborate on the correlation between the elemental composition of the placer gold and the original deposit source for the respective districts. This research analyzes the composition of placer gold from multiple districts and within the same district. There are a number of elements, which can, in various quantities, be present in placer gold particles. Native gold can be in complete solid solution with native silver and contain additional elements including Cu, As, Pb, Fe, and S. The chemical signature of the gold is determined by the thermodynamic conditions of precipitation and transport as well as the total metal content of the system. As Townley et al. (2003) explains, “These thermodynamic conditions and metal budget differ from one type of hydrothermal deposit to another, and hence different deposit types will each have a characteristic gold compositional signature.” Identifying this signature can be a highly valuable tool in exploring for gold, as it can not only be used to determine the original source deposit of the placer gold, but provide valuable insight as to the erosion level of the present deposit."

Jan 1, 2016

By Jean-Michel M. Rendu

Increasingly, geologists use geostatistical methods to evaluate drilling programs. The complexity of the methods varies with the nature of the available sample information, the objective of the statistical analysis and the geologist's experience. Occasionally, estimating the average sample grade is all that is required. In other instances a semivariogram calculation may be considered. If sufficient data is available, the geologist may wish to estimate blocks or panels of complex shape, using the kriging method of evaluation. Historically, the use of geostatistics by geologists has been limited by a number of factors, most significant being the difficulty in accessing and using computer programs needed to complete the necessary studies. Geologists are often working in remote areas from which electronic communication is unreliable, if not impossible. Even when access to computer programs is technically possible, the costs incurred in accessing and using these programs are often considered prohibitive. In many instances using the programs requires an understanding of computer systems far beyond that which a field geologist can justifiably be interested in acquiring and maintaining.

Jan 1, 1984

By Thomas Pea, Heiner Kontrus, Jérôme Steinkühler

In tunnel condition assessment, the trend is towards comprehensive 3D measurement combined with high quality image texture to document and quantify damages to the tunnel surface and to create a cohesive data base of the structural conditions throughout its lifespan. The faster such measurements can be made on site, the less it impacts traffic conditions of the highly sophisticated subway systems. The Dibit high-speed 3D scanning system which is based on Photogrammetry and LiDAR technology enables data acquisition in tunnels at a speed of up to 60 mph. Given the high rate of speed the system can operate, tunnel shutdowns can be drastically reduced, and tunnel safety increased. The photorealistic texturing of the 3D-model allows the identification and analysis of smallest material damage (e.g., cracks ≥0.3 mm wide). The publication illustrates technical details and 3D results of the innovative system from measurements that were performed in the subway tunnels of the Bay Area Rapid Transit System in San Francisco, CA (total length 66.23 km).

Jun 13, 2021

By Norman A. Nadel

Those of us who have directed our efforts toward the construction of tunnels have long maintained that tunnel construction is more closely an art than it is a science. We have spent time underground with hard-bitten, tobacco chewing shift bosses and superintendents who have made seat-of-the-pants decisions at the face which have been based upon their long experience underground coupled with uncanny intuition. The courage and skill of these men in the performance of their art is legendary. Without question, they have constituted the backbone of the tunnel construction industry. But just as John Henry, the steel driving man, despite his stout heart and dedication to his task, was supplanted by the steam drill, I fear that our tunnel stiff, at least as we have known him, will become an endangered if not extinct species. The reason for this is clearly that tunnel construction is slowly but inexorably making the transition from being an art into being a science, and more and more its performance is requiring the services of scientists as opposed to artists. The tunneling art has been undergoing change for many years, and yet until recently the changes have not been basic. We have improved the way we do the same old things. For example, John Henry would be flabbergasted if he saw the rock drills we use today. He would not have engaged in the legendary drilling contest with one of our modern drills, He would have simply conceded defeat.

Jan 1, 1970

By A. Andreas

The transportation of mine products incurs a cost which can have a significant bearing on the competitive position of the product. This statement not only holds true for the transportation of the finished product but certainly as much for the in- plant haulage of the raw materials. Extensive literature is available both in North America and Europe on all aspects 02 these questions and to cite only a few of them: Pipelining of slurries, oil and gas, shipping of minerals and oil from the Arctic by icebreaking tankers, airlifting of metals or concentrates, etc. This paper is concerned with movable crushing plants as opposed to stationary and their influence on the in-plant transportation, that is trucks vs. belts.

Jan 1, 1973

By J. K. Brooke

Fluorine is a lively element in both its chemical and economic behavior. It was not isolated as an element until 1886 by Moissan. However, its principal source to this day, fluorspar, was known and its special merits recognized long before that time. Our own mining brother, Agricola, is credited with having named fluorite, the mineral name, in 1546 from the Latin, "fluere", to flow. It made things melt and was already being used as a flux. Because fluorspar has been found as a relatively common gangue mineral in metal ore veins, it has long attracted the attention of geological thinkers seeking to, explain the whys and wherefores of veins. Fluorine has been thought of as one of the principal mineralizers, holding metals in ascending vein solutions for deposition close enough to the eventual surface to be accessible for profitable mining.

Jan 1, 1964

By Duk-Won Park

A new gage for monitoring fractures in underground openings was successfully developed utilizing the reflection photo-elastic technique. The gage may be used to detect crack initiation in mine openings or tunnels so that remedial action may be taken to prevent further deterioration. Fringes concentrated around the cracks were spread by the use of rubber backing. Crack growth as little as 0.003 inch up to as much as 0.1 inch width were detected in this study. Variation of gage materials will provide alternative ranges. The feasibility of the method was tested and calibration was made in the laboratory study. Field study successfully demonstrated the capability of applications in detecting mine roof crack development.

Jan 1, 1982

By Neal P. Cochran

The United States is faced with increasing demands for electricity, coupled with continuing demands for crude oil and gas. Superimposed on these' national requirements are our national requirements for clean air and elimination of thermal pollution of our rivers. From the coal viewpoint, this situation is complicated still more by the rapid advances in nuclear power. In this paper, I hope to show a way to use our Western coals as a solution to this involved national problem by producing: 1. High quality crude 2. Low cost power 3. Economic byproducts We could expect these products to be made at one site in an integrated plant that would mine (extract) coal, process it, and convert it to electricity. Perhaps the most important attribute of the plant is its reduced water requirement and the elimination of air pollution from the power cycle. Quite logically, such a plant would probably recover valuable byproducts, such as pipeline gas, sulphur, cement, aluminum, and the like. Although the plant projected in this paper is a conceptual one, it is based on work now underway by Government and industry. Prediction of the future is a most hazardous occupation, but plants such as the one projected are based on current knowledge and can be expected to reach commercial operation in the near term future.

Jan 1, 1967

By L. G. Wilson

In our comparison of California and Turkish colemanites, we should first place the discussion in context. In order to exclude technical considerations, which are not germane to this paper, we must make the manifest and basic observation that if colemanite were not acceptable for the production of glass products it would not be used, and we would not be interested in this comparison at all. Suffice it to say that the colemanites, being calcium borates, provide a necessary flux in glass manu¬facture, together with the requisite degree of physical strength and chemical durability which can be achieved only by the use in glass of a. flux substanti¬ally free from alkali; so the sodium borates are automatically excluded from the production of textile fibers. Thus we have today under consideration only California colemanite, Turkish cole mite, and, because it provides a degree of competition to both, ABA, or anhy¬drous boric acid, which, although it is a refined intermediate and of much higher cost, it is also of a much higher degree of purity, and its characteristics can easily be modified to produce a desired end product, so we must include it in any consideration of high quality borates. [Calcim Borate Pentahydrate] Colemanite is a [calcium pentahydrate,] with the formula Ca2B6011.5H20. It has a theoretical B203 content of 50.8%.

Jan 1, 1973

By Philip Lindstrom

Retreat mining, using yielding steel friction props, over a seven-year period has been successful at a uranium mine operated by Hecla Mining Company in southeast Utah. The support system allow good roof control, maximum profit, complete extraction, and good ventilation. Unusual subsidence observations were made in that some of the surface was raised rather than lowered, Longwall mining, commonly practiced in European coal mines, has a potential of broader application because of mechanization possibilities and better roof control and ventilation at greater depths.

Jan 1, 1964

By Dennis A. Fenton

This paper presents some techniques and data required to design large ball mills. The advent of larger size mills leads to consideration of the gearless drive as a practical solution to utilize large horsepowwers. The particular shell structure under consideration is subjected to thermal as well as magnetic loads. The magnitude of the inertia, magnetic and shell temperature characteristics have a very significant effect on the design and performance of the hydrodynamic pivoted shoe bearing. Particularly since these bearings have lower frictional resistance properties than hydrostatic trunnion tee rings. The structure of the mill is designed for long life. Parameters involved with the fatigue life of the structure are discussed together with some of the more important aspects of the design.

Jan 1, 1975

By Wallace W. Key

Problems of marketing industrial minerals to chemical manufacturers are manifold. In addition to the difficulty of establishing demarcation lines between "crude" and "processed" industrial (nonmetallic) minerals, and "industrial mineral compounds" further uncertainty exists because some chemical manufacturers do not talk the same language as the industrial mineral producer. For example, paint technologists use "rutile" and "anatase" to describe highly refined chemical compounds. The earth scientists use these terms to describe naturally occurring minerals. Further, marketing research problems are intensified because of the overlapping data of the Standard Industrial Classifications (SIC) groups, and the inexactness of "Chemical Industry," "Chemical and Allied Products Industries," and "Chemical Process Industries," which are widely variable in meaning but are often used interchangeably. Bureau of Mines information Circular 8244, "Minerals for Chemical Manufacturing," was the out¬growth of an attempt to unravel some of the problems caused by overlap of statistical data compared with actual industry practices. Using this study as a base, specific industrial mineral applications of some important sub-industry groups were analyzed for the; California chemical industry. Differences between local and national practices were compared. Practices usually differed, depending on cost and availability of alternate minerals, climate, idiosyncrasies, local regulations, and other conditions. Bureau of Mines Information Circular 8260, "Mineral Fillers for the California Pesticides Industry," is the first such analysis of, a sub-industry group. Other such studies are underway. Obtaining national data is easy, but to be able to compile meaningful information which can be revealed on a regional and State basis generally is difficult and often impossible. This paper will briefly emphasize some of the industrial mineral problems encountered, and bring out the needs and benefits being derived through the continued cooperation of authoritative officials concerned with supply and consumption of industrial minerals in government and industry.

Jan 1, 1965

By James R. Dunn

The nature of water and clay in carbonate rocks is currently being investigated at Rensselaer Polytechnic Institute by various thermal and sorption techniques. Two basic concepts 'led to the present research. (1) To explain the expansion and contraction on wetting and drying of some unsound argillaceous carbonate rocks, it was postulated that the pore space around each clay particle is such that when water is sorbed by the clay, force is exerted against the pore walls. (2) The clays in expansive rocks are rejected from the growing dolomite crystals during their growth, and form a more or less connected network, thereby becoming "wettable," or available to water. New quantitative cold differential-thermal-analysis (electrocalorimetric) equipment was designed and constructed to check the "limited space" and "wettable clay" concepts and to determine the thermal nature of the transition of water to ice in rocks. This DTA equipment can detect the release of heat in freezing of less than 0.001 per cent water in a rock. Twenty-three rock cores (nine sound and fourteen unsound) and 4 procelain cylinders for standards were studied. In the nine sound rocks and in all the procelain cylinders, the rapid freezing of from 50 to 100 per cent of the water was readily detectable after 7 to 10° C of supercooling. No further freezing could be detected to -20° C. However, in eleven of the fourteen unsound rocks, no freezing was detected to as low as -40° C; in the other three, less than 50 per cent of the water froze. As a check of the DTA measurements, adsorption isotherms were determined for all materials. Calculations of theoretical freezing points for sorbed water again demonstrated that the least sound rocks had the most nonfreezable water. "Frost" sensitivity in these carbonate rocks is, therefore, probably not the result of the force of expansion of water to ice. The disruptive force is believed to result from expansion of sorbed, ordered water on clay surfaces. The relationship between the unfilled rock pores after 24-hour water saturation and the water sorbed at 85 per cent humidity at 30° C (i.e., the theoretical nonfreezable water delineates the sound and unsound carbonate rocks.

Jan 1, 1966

By M. Moss Stanley, Ronald P. Klepper

The objective of this chapter is to provide data that will assist in the selection and sizing of equipment utilized in the filtration method of separating solids from liquids. It should be recognized at the outset that in some situations more than one option may be available to achieve the target desired. In some cases purely technical objectives may be sacrificed because of cost considerations, design factors or other elements in order to satisfy optimization within the flowsheet and/or to provide bottom line results. Before considering available options, and prior to the next step of sizing out the selection, the operating criteria should be set down. The test work to develop selection and sizing data will be based on this data and the final products desired. This will help to establish initial parameters. A. GENERAL DATA 1. Material to be filtered: a. Solids b. Mother liquor 2. Feed rate of slurry in GPM 3. Density of slurry: Sp. Gr. Solids 4. Slurry: Temp. pH Viscosity 5. Source and method of feed 6. Valuable product: Solids Filtrate Both 7. Details on: Volatility Toxicity Stability 8. If flocculant is indicated, what has been used? 9. Describe product: (i.e., fibrous, cor 10. rosive, abrasive, inflammable, explosive, pasty, 11. Does product alter or require special environment during transport? 12. What type of filter media has been used successfully? 13. Is there any objection to use of a filter aid? If not, is there any preference? B. SOLIDS DATA 1. Sp. Gr. Bulk density 2. Screen analysis 3. Desired percentage moisture in cake 4. Solubility (state conditions): In mother liquor In wash water 5. Description of cake: (i.e., amorphous, fibrous, crystalline, colloidal, gran¬ular, thixotropic, 6. Special requirements for moisture de¬termination? 7. Can solids be compressed during dewatering? 8. Proposed product handling 9. Subsequent thermal drying or other pro¬cedure C. FILTRATE 1. Is separation of wash water and mother liquor desirable?

Jan 1, 1986

By R. A. MacGregor

The Stanreck mine of Stanreck Uranium Mines Limited in located on Quirks Lake in the Elliot lake - Blind River area of Northern Ontario. It is approximately 25 miles north of the north shore of Lake Huron, equidistant between the cities of Sudbury and Sault Ste. Marie. The property was developed ad brought into production at a rate of 3,000 tens of ore/day during the uranium boom of the mid 1950's. By 1960 mine waters were becoming quite acid through the activity of bacteria. Treatment of this water was begun for pollution control and a small amount of uranium which had been leached from the ore by these acid waters was recovered. Development of bacterial leaching with a view to increasing production by this method commenced in December 1962. Subsequently, it was succeesfull in producing 10,000 - 15,000 lbs. of U308/month. Since late 1964 uranium production has been obtained solely from bacterial leaching. A rare earth concentrate was also made for its yttrium content during 1966 and 1967. This paper describes the development, operation and methods used in the underground bacterial leaching process.

Jan 1, 1969

By Raymond Mancha

"Conventional" coal dryers really do not exist. What we really mean to say is that there are many and varied kinds of coal dryers -- and the "air handling problem" is really the only portion of it which has been approached for solution by conventional methods. It now appears that these conventional methods need supplementing by some new, relatively unconventional apparatus. In order to approach this matter with mutual understanding, here is a quick survey of the coal drying art. Figure #1 shows a McNally Pittsburgh Pulso Dryer, In the McNally Pulso Dryer, the coal is fed-onto the screen by a rotary feeder assuring even distribution of the coal. As the coal travels forward due to the action of the screen, it is subjected to a controlled pulsating flow of hot gases. T ese originate below the deck and are directed up through the moving bed of coal. Fines sifting through the deck are dried in the hopper below the screen as they fall through the hot gases to an evacuation screw. The coal remaining on the screen is dried to the desired degree when it reaches the discharge end. At this point, it is directed down into the evacuation screw to combine with the fines, or it may be discharged as a separate product. As the coal travel down the screen, it is subjected to intermittent upward currents of hot gases. These first distend the bed allowing the gases to come into intimate contact with the coal particles for rapid and efficient heat transfer. Then, as the flow of gas is cut off, the bed settles and the extreme fines sift through the screen preventing their being carried away into the exhaust system.

Jan 1, 1958