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By Michael Beyer

Following the last Cholera Epidemic in 1872, resulting in approximately 400 deaths, the City Council of Munich decided to re¬place the former water supply system within the city limits by tapping new water supply areas outside of the city. Since 1883 Munich has been obtaining its water from the Mangfall River catchment located some 35 km to the south. Its most distinguishing characte¬ristics are as follows: 1) the water is free-flowing, i.e., a pumping system is not required as the catchment area is 100 m higher than the city; 2) the water does not normally have to be treated, meaning "spring fresh" tap water. On a daily basis, 300,000 m3 of water flow through the more than 100 year old pipes, accounting for 70% of the city's daily need. There was originally no requirement of a water tight system as strategically installed drain pipes prevented the build-up of exter¬nal water pressure on the lining. As the qua¬lity of today's water has become significant¬ly worse, the tunnels are now in dire need of restoration or replacement.

Jan 1, 1995

By R. S. Saunders

Congress, under the Nuclear Waste Policy Act of 1982, as amended, charged the U.S. Department of Energy (DOE) with the responsibility for safe and permanent disposal of high-level radioactive waste in a geologic repository. The waste will consist of spent fuel from commercial nuclear generating plants and reprocessing activities. Under direction of this law DOE is currently evaluating Yucca Mountain in Southern Nevada as the candidate site for a potential high-level radioactive waste repository. Presidential, Congressional and State of Nevada approval are needed for repository construction to proceed after successful completion of site characterization and recommendation of the site to Congress. The DOE will submit a license application to the Nuclear Regulatory Commission (NRC) to construct the geologic repository. Following successful construction DOE will update its license application to operate the repository.

Jan 1, 1993

By RICKARD HANSEN

Vehicle fires in underground mines pose a certain risk for which measures to prevent or mitigate the fires are highly important. Fire protection measures can be divided into active and passive measures, where active measures require an external power to work in the event of a fire, and passive measures could include an existing partition preventing fire spread. As passive fire protection does not rely on activation, it is expected to provide high reliability and a robust solution, and should be considered during the design process. This paper investigates passive fire protection measures that could be implemented in the design of mining vehicles. It was found that passive fire protection should include the use of several measures simultaneously to ensure fire protection throughout the different phases of a fire. Threshold distances for fuel components were calculated, and it was found that combining hydraulic hoses and electrical cables resulted in larger threshold distances. A pool fire along the underside of a vehicle will pose a certain risk, and passive measures should be focused on ignition prevention, making high demands on the insulation/shielding along the underside. Any occurring tire fire may pose a challenge, and the priority should be on preventing ignition. Potential measures include shielding the wheelhouse and applying fire-resistant sealings.

By Michael Rehbock-Sander, Romed Insam

"INTRODUCTIONThe idea of building a summit tunnel under the Brenner occurred to the Italian engineer Giovanni Qualizza as far back as 1847. But it was to be another 160 years to pass before a base tunnel was to be built.In 1971 the idea of a tunnel at the Brenner was dusted off again. The UIC, the International Union of Railways, commissioned a study for a new Brenner railway with a base tunnel. By 1989 three feasibility studies had been drawn up which formed the basis for further planning of the Brenner Base Tunnel.This was the start of the planning activities. In 1994, the European Union included the Berlin-Naples corridor in the list of priority projects. Ten years later, Austria and Italy signed a State Treaty to build the Brenner Base Tunnel. In that same year, what is today the BBT SE was established.PROJECT DESCRIPTIONThe Brenner Base Tunnel (BBT) with a length of 55 km is the centrepiece of the Helsinki-Valletta Transeuropean Traffic Corridor from Finland to Southern Italy. The BBT tunnel system connects in the north with the Innsbruck station (Austria) as well as to the feeder routes in the Lower Inn Valley, and opens to the south with the projected new line in the direction of Verona (Italy). The tangible design efforts have been underway since 1999; the start of construction of the first section was in the year 2007. The project is financed by the Italian and Austrian governments (each 30 %), as well as by the European Union (40 %).From 2027 onwards the Brenner base tunnel, including the existing lines connected with it, will carry a daily average of 330 trains (approx. 80% cargo trains and 20% passenger trains)."

Jan 1, 2016

By J. E. Bevan

Once mining compromises the stability of a rock mass, the dangerous task of roof bolting begins. Many attempts have been made to automate this process, but there are still many refinements that need to be made. In the past, roof bolting modules were designed around the abilities of a human operator. Currently, researchers are taking a new approach that focuses on designing modules that can utilize bolting methods that are easily automated. A non-rotating anchor that is locked into position by a linear force (as opposed to a rotational force) was designed by researchers at the U.S. Bureau of Mines. Once the bolt is secured in the bolt-hole by the anchor, the bolt is tensioned and a collet is used to secure the other end of the bolt. This process replaces the traditional bolt-nut fastening method. This program is part of an effort at the U.S. Bureau of Mines to automate the coal mining process.

Jan 1, 1994

By N. B. Aughenbaugh

Subsidence due to abandoned coal mines has received copious attention recently. This is a result of many factors such as the enactment of new mining laws and the effect subsidence has on land use over the mines. Prediction of subsidence features and the time aspects over supercritical extraction (i.e., longwall and high extraction ratio pillaring) is relatively accurate. However, predicting when subsidence will occur and the surface features' size and shape above subcritical extraction of room and pillar mining is not yet possible. This paper will discuss the factors that influence the time aspects of subsidence in room and pillar mining.

Jan 1, 1983

By M. D. McInnis

The Jualin Gold Prospect is centered on Johnson Creek, approximately 40 air miles north-west of Juneau, Alaska. The property is on the southern end of the Kakuhan Range with Berners Bay immediately to the south and Lynn Canal to the west. The property is accessible directly by helicopter from Juneau or by float plane to the head of a 5.5 mile gravel road that begins on the north side of Berners Bay and terminates at the old workings of the Jualin Mine near the center of the property.

Jan 1, 1989

By C. W. Schultz

The Alabama tar sands of the Hartselle Sandstone formation present a more difficult problem in primary extraction than do the Athabasca tar sands. In contrast to the Athabasca tar sands, the Alabama tar sands are "oil wetted" and the contained tar, or bitumen, is of much higher viscosity. A physical beneficiation scheme was developed in which clean sand from an external source was used as a scrubbing medium. High intensity scrubbing liberated the tars which are readily recovered by froth flotation. Locked cycle tests have shown that, after the use of an initial ration of clean sand, the system produced enough new clean sand to be self sustaining.

Jan 1, 1992

By Ted D. Maki, Joseph B. Taylor

INTRODUCTION FMC's Paradise Peak mine, located 13 Ian (8 miles) south of Gabbs, Nevada, became opera¬tional in April of 1986 (Figure 1). It was designed and built by Davy McKee, who was instrumental in equipment design and selection. It is the 7th largest gold deposit in the United States with defined reserves of 10.9 mt (12 million st) containing 34 million gms (1.1 million tr oz) of recoverable gold and 933 million gms (30 million tr oz) of recoverable silver. The mine extracts ore by the open-pit method, taking advantage of a 1.5:1 stripping ratio. The mill operates at a 3600 mt/day (4000 st/d) capacity. Crushing is done in three stages to achieve an ore size of minus 0.635 cm (0.25 inches). Grinding further reduces the ore to 85% minus 100 mesh. The ground ore is treated with cyanide in agitated leach tanks and then washed in the counter-current decantation (OCD) thickeners. Zinc is added to the clarified, deaerated pregnant solution to precipitate the precious metals. The precipitate is acid digested to eliminate excess zinc, filtered and retorted to drive off contained mercury. The retorted precipitate is then fluxed, melted and poured through cascade molds. Dore bars are cleaned for shipment and the slag is sent to an in-house slag treatment system. ELECTROSTATIC SEPARATION The dry electrostatic slag treatment system at Paradise Peak is the first installation of its kind. Electrostatic separation has been widely used in mineral processing since the early 1950's. A brief discussion of the theory behind the process is helpful to those not familiar to electrostatic separation. Charging and sepa¬rating slags, dry minerals or other materials by ion bombardment is the most common form of electrostatic separation. Millions of tonnes of minerals are processed each year by this method. In an ion bombardment separation, granular material is fed onto a grounded metal cylinder (or roll) and charged by a corona-producing electrode placed above the roll's surface (Figure 2). While both conductors and non¬conductors become charged, only the conductor is able to lose its charge. The charged non¬conductor, as it rests on the roll's surface, "sees" an oppositely charged image of itself in the metal surface. It is attracted to the image charge, becomes electrostatically pinned to, and moves with the roll's surface. The conductive particle also sees an image and is attracted to it. But upon touching the roll's surface, it discharges rapidly to the grounded surface and is thrown free from the roll's surface with a projectile motion. In the case of precious metal slags, the con¬ductive particles would be metallic prills of dore metal; and the nonconductive particles would be the slag, free of metal. Middling grains, generally, are in the form of a metallic prill encased in or incompletely liberated from slag. LABORATORY TESTING A number of precious metal slag samples have been tested in the laboratory. It has been found that the composition of slags vary widely from one refinery operation to another. Typical laboratory procedure is to crush and size the slag followed by two-stage lab-scale electro¬static separation. The conductor fractions from the first and second pass are then combined as a prill concentrate; middlings fraction and clean slag tailings from the second pass are held separate. Selected results from laboratory testing are shown in Table 1. It is important to note in Table 1 that the assays represent overall silver and gold, not metallic values. From experience, the laboratory results are typically lower in grade and recovery than the industrial installations. This is largely due to the hydroscopic nature of precious metal slags coupled with the high local humidity in Carpco's Jacksonville, Florida, location. Relative humidity in Jacksonville can range form 60-95%, while most mining locations in the

Jan 1, 1987

By A. P. Mehta

The role of microorganisms in the leaching of metal sulfides is well established (Torma, 1977; Murr, 1980). However, this established knowledge applies mostly to chemolithotropic microorganisms such as Thiobacillus ferrooxidans which function optimally in leaching catalysis between 25-35° C, and in a pH range of 2-2.5. Although leaching with thermophilic microorganisms capable of extending the range of catalytic viability beyond 35° C is also documented, there are few if any attempts to optimize or extend sulfide concentrate leaching with thermophilic microorganisms. When mixed metal sulfides or other materials having different rest potentials (referenced to the standard hydrogen electrode, SHE, in the electromotive series) make contact in a conducting, aqueous medium, the contacting members will act as an electrochemical cell, with the member having the higher rest potential assuming the role of an electrical cathode. In leaching reactions involving such galvanic couples, the cathode becomes passivated, while the anodic member reacts vigorously due to the electro- chemical reaction which occurs (Hiskey and Wads- worth, 1975). Serry, eta1 (1978) observed that when chalcopyrite and pyrite were in intimate contact in natural ores, the chalcopyrite reacted vigorously by galvanic conversion as a result of the higher rest potential (~ 0.63 V) as compared to the chalcopyrite (~ 0.53 V). In addition, it was postulated that because of the elemental sulfur which can form on the anodic chalcopyrite in this galvanic conversion process, reactions in acid-bacterial medium would be expected to have accelerated copper extraction because of the conversion of any sulfur product layer on the chalcopyrite anode to sulfuric acid according to the following general reactions: [MS?M2+ + S° + 2e- (1) and 2S° + 302 + 2H20 bacteria?-2H2SO 4 (2)] where M in reaction (1) designates the metal (or metals in the specific case of chalcopyrite) to be released to solution by galvanic conversion.

Jan 1, 1982

By J. W. Mustard

The Macmillan Pass tungsten property (MacTung) is the largest known copper-tungsten, calcic, exoskarn deposit in the Western Hemisphere. Located on the border between the Yukon and Northwest Territories in northwestern Canada, the deposit crops out on Mt. Allen within the Selwyn Mountain Range. It was discovered in 1962 by a subsidiary of AMAX Inc. and has since been explored by 16,300 meters of surface and underground diamond drilling and by 800 meters of underground development. Geologic reserves are in excess of 30 million tons, grading slightly less than 1.0% WO3. Scheelite (CaWO3 ) is the main mineral of economic interest. Accessible by road, the property is not in production. Previously estimated reserves at MacTung have been unable to fully utilize all the geological controls on mineralization. In the past three years, however, an intensive program has been underway to improve our understanding of the deposit and to use the resulting information in a more precise way. This paper will discuss the key aspects of the geology as they specifically relate to reserve estimation and will demonstrate how these controls are being used in a geostatistical model of the deposit.

Jan 1, 1985

By Bruce Hern

The last 10 years have seen a dramatic increase in the requirements for product coal quality control. This has led to electric utility sulfur scrubbing, metallurgical blast furnace optimization and coal producer blend and yield optimization. To achieve this improved level of control, coal producers are designing facilities that emphasize new technology. New facilities will be designed and existing facilities will be retrofitted with state-of-the-art technology to meet quality control standards that are dictated by the market. The first step in designing for process control requires the identification of those parameters to be controlled and the upsets that can cause variances in the final shipped product quality. The most common parameters that require control are the surface moisture (%), ash (%), pyritic sulfur (%) and gross calorific value (Btu). Total moisture is that moisture that exists on the surface of the particle and is inherent in the particle itself. For the purposes of control, the total moisture is monitored, while surface moisture is controlled. Ash is the inorganic residue remaining after all other constituents are burned away at 75O°C( 1382°F)(ASTM, 1992). Sulfur is the amount of total sulfur that exists either as pyrite (FeS2), inorganic sulfate (FeS04), or organic sulfates (C4H4S) (Leonard, 1979). Currently, pyrite is controlled and total sulfur is monitored. The gross calorific value is the amount of heat produced when a unit quantity of coal is ignited under specified conditions. In this case, a l-g (0.03-oz.) sample of coal is ignited in an isoperibol waterbath and the temperature rise of the water bath is observed. The moisture and ash-free (MAF) Btu is relatively constant for a given seam, resulting in the whole calorific value being a function of the moisture and ash levels (Leonard, 1979).

Jan 1, 1994

By J. Kennedy

Rare Earths: Understanding The United States complete failure of status and relevance in Rare Earth Oxides, Elements and Alloys. Although rare earth oxides are strategic and critical in their own right, elements and alloys are even more important for the development of "Green Technologies" and advanced weapons systems. America does not have an active domestic source of rare earth oxides. America does not have any Heavy Rare Earth Elemental or Alloy capabilities. The magnitude of this failure continues to become more apparent as the manufacture of REO based electronics and magnetic components moves eastward towards China. China has succeeded in outmaneuvering The United States and the world in its quest to control the Rare Earth Oxides, Elements and Alloys, and the many industries dependent upon REO. What can be done?

Jan 1, 2010

By David J. Boron

The United States has the largest total (364 billion metric tons) and recoverable (182 billion metric tons) coal reserves in the world.1 However, progressive coal utilization in this country has been hampered by environmental constraints, such as restrictions on sulfur dioxide, nitrogen oxides, and particulate emissions. New technologies are being pursued both to appease these environmental concerns and improve economic performance and process efficiency. These technologies, however, have not reached the level of effectiveness required for optimum operation. If more stringent emission standards are imposed, it is likely that the coal industry, and the industrial and utility sectors will look increasingly toward the successful development of new and advanced coal cleaning technologies in order to continue and promote the use of coal in this country. The EPA New Source Performance Standards In 1979, the Environmental Protection Agency in response to the amendments to the Clean Air Act of 1977 issued new source performance standards (NSPS) for utility and industrial boilers. The NSPS set emission standards for sulfur dioxide, nitrogen oxides, and particulates affecting boilers of 250 MM Btu per hour heat input or 'greater that started construction after September 1978. Plants starting construction or in operation before September 1978 remained subject to the provisions of the regulations promulgated in 1971, i.e., SO2 emissions of 1.2 15/MM Btu. The NSPS for SO2 emissions provides a sliding scale for SO2 reduction depending on the sulfur content of the run-of-mine coal, with an upper limit of 1.2 lb of SO2 per million Btu and a minimum emission level based on 70% SO2 removal. Table 1 summarizes the EPA NSPS for SO2 emission standards.

Jan 1, 1983

By Thomas A. Wheeler, Robert O. Keys

The choice of the flotation reagent that suits a particular coal has become more complicated with the development of new, more efficient reagents. Frothers and conditioning reagents, in particular, have experienced a dramatic reevaluation of their role in floating various types of coals. This paper offers a better understanding of how each of the following factors contributes to the reagent selection: 1. Natural Flotability 2. Degree of Oxidation 3. Size Distribution 4. Percent Solids in Feed Slurry 5. Fluctuations in Plant Feed 6. Limitations on Froth Handling 7. Clean Coal Specifications 8. Ash Content in Feed a) discrete ashable minerals b) inherent ashable minerals 9. Water Chemistry 10. Petrographic Composition of Coal 11. Free-Swelling Index 12. Convictions of Customer The application of conditioning reagents - both promoters and emulsifiers can substantially improve the coal recovery. Some low-rank, hydrophylic coal, previously considered unfloatable can be economically recovered with the use of the proper reagent.

Jan 1, 1986

By Karl P. Norrena, Clayton V. Deutsch

Ore and waste cannot always be visually separated. The distinction between ore and waste may need to be made on the basis of blasthole sampling. Hand drawn dig limits or computer-generated contour lines do not account for uncertainty, economics or equipment. Geometric methods for interpreting grade information such as the polygonal or triangulation methods share the same limitations as contouring. Geostatistical techniques exist for the realistic modeling of grade variations and uncertainty. Decision analysis techniques exist for the binary classification of ore, and waste blocks in the presence of this uncertainty. Block-by-block classification is not enough; mining equipment cannot exercise free selection of blocks. There is a need for procedures to determine optimal dig limits that account for (1) the uncertainty in the grades, (2) the economics of risk-qualified decision-making, and (3) the ability of the mining equipment to dig to specific limits. This paper presents a procedure for optimal determination of dig limits that account for these constraints. Simulated annealing (SA) is used with modest computational requirements because the number of variables is relatively small. The solution of the optimization problem is dig limits that maximize profit under multiple constraints. The method is illustrated with different constraints and tested against hand drawn dig limits in a "Dig Limit Challenge," which illustrates the efficacy of the new method.

Jan 1, 2002

By Seppo] [Kreula

Outokumpu Oy has acquired considerable experience with on-stream X-ray fluorescence analyzers and with computer control of flotation processes over several years. It became evident at the outset of this work that a reliable and accurate on-stream analyzer was more than a collection of different pieces of hardware linked together. Extensive work was done to develop an integral analyzer system, beginning with process samples through the spectrometer to report typewriters, recorders and the control computer. To date, over ten Courier-300 analyzer systems based on this development have been installed world-wide, several of which provide the key information for successful computer control systems. Computer control of flotation processes has been under development at the Pyhäsalmi concentrator since 1968. Two different control strategies have been implemented. The copper flotation is controlled by means of a mathematical model and economic criteria, whereas the "evolutionary operation principle" is applied to the zinc flotation. The computer control system installed at' the Vuonos-mine has been developed according to the same guidelines. In order to consolidate this wide experience, a flotation computer control system, Proscon-100, was developed by Outokumpu Oy, and the first system was installed at Kotalahti in 1972. In addition to the technological experience, enough information has also been gathered to illustrate the economical, benefits accruing through the use of these advanced tools of automation.

Jan 1, 1973

By C. Jardine

The concept of the system is to minimize costly unscheduled breakdowns of equipment by replacing components earlier than their "life" expectancy. Periodic unit services are scheduled according to pre-set constraints. Service sheets are generated by matching a job and component master listing based on assigned cyclic component lives. The system can provide accountability of all man-hours reported and history information can be selectively retrieved. By reducing unscheduled equipment shutdowns, this system allows for better utilization of manpower and an overall improvement in equipment reliability and availability.

Jan 1, 1979

By Jessica M. Wempen

"Differential Interferometric Synthetic Aperture Radar (DInSAR), a satellite-based remote sensing technique, has application for monitoring subsidence with high resolution over short periods. DInSAR uses radar images to measure centimeter-level surface displacements. In the images, ground resolution can be relatively high, with each data point (pixel) representing the average displacement over an area of several square meters. The image data are acquired regularly which allows subsidence to be monitored sequentially over short periods; imaging periods typically range from weeks to months.Monitoring subsidence over short periods with high spatial resolution has potential to provide insight into the dynamics of subsidence and into relationships between mine advance and subsidence. In this study, for three longwall mines in the western United States, initial subsidence occurring at the start of longwall advance is quantified over short periods (12 to 72 days). C-band interferometric wide swath Synthetic Aperture Radar (SAR) images from the Sentinel satellites are used to quantify the subsidence. Overall, the data show initial development of subsidence, expansion of the subsidence trough, and the advance of subsidence in the direction of mining.INTRODUCTIONApplied Differential Interferometric Synthetic Aperture Radar (DInSAR)Differential Interferometric Synthetic Aperture Radar (DInSAR) is a satellite-based remote sensing technique that can be used to quantify small displacements of the Earth’s surface. Using data from the Seasat satellite, which was launched in 1978 (Jet Propulsion Laboratory, 2018), studies by Goldstein, Zebker, and Werner (1988) and by Gabriel, Goldstein, and Zebker (1989) applied Synthetic Aperture Radar (SAR) interferometry to topographic mapping and displacement monitoring. These studies established the potential for broader applications of radar interferometry. Studies by Foxall, Sweeney, and Walter (1998), Wright and Stow (1999), and Carnec and Delacourt (2000) represent some of the earliest evaluations of DInSAR for mine subsidence monitoring. All three of the studies demonstrated the application of DInSAR for quantifying mine subsidence. They also demonstrated difficulty accurately measuring subsidence over long periods due to data decorrelation. DInSAR continues to be evaluated as a tool to quantify surface deformation related to active and historic mining. For example, see Vervoort and Declercq (2018), Wempen and McCarter (2017a), Chen et al. (2013), and Liu et al. (2013). Technologies associated with SAR interferometry continue to develop. Recently launched satellites have relatively high spatial and temporal resolutions, and data processing methods and data accessibility are improving."

Jan 1, 2019

By Duncan M. Lamb

Commercial computer "time-sharing" is a new and powerful tool for the engineer. It is a system of virtually simultaneous use of a digital computer by several individuals. Access to the computer is by means of a conventional teletypewriter which transmits over the regular telephone lines to the computer which may be located any distance from the user. Complex or repetitive computations can be programmed and the speed of computation is many times that which one can do with slide rule and desk calculator. The availability of such a commercial computer "time-sharing" system offered an opportunity to transform a tedious and time-consuming task into one that requires only a few minutes. Until the work of F. C. Bond produced widely accepted mathematical statements concerning the performance of grinding mills, the selection of the proper size equipment was done by comparison with similar operating equipment. Allis-Chalmers systematized Bond's work in a bulletin published in 1963 but the calculations are laborious and the final mill selection still required comparison of the calculated power draw with the power requirements listed in equipment catalogs. This was, however, a step forward from previous procedures. This paper discusses a rapid and simple method of determining the size and power requirement of overflow ball mills. A shared-time computer program has been developed which rapidly calculates and displays the physical dimensions, power requirements, grinding media size and quantity, as well as the important correction factors used. All of these data are calculated from input information which is usually available.

Jan 1, 1969