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By Fred N. Kissell, George H. Jr. Schnakenberg

INTRODUCTION A variety of instruments are available for measuring or monitoring the performance of underground mine-ventilation systems. In general terms, the instruments may be classified as those that measure air velocity and those that measure gaseous concentrations. All costs herein are in terms of 1978 US dollars. The mention of a specific manufacturer or device is not intended to be an endorsement by the US Bureau of Mines. AIR-VELOCITY INSTRUMENTS The basic instruments used for measuring the air velocity in mines are the vane anemometer and the smoke tube. Vane Anemometer Of the air-velocity instruments, the 102-mm (4.0¬in.) vane anemometer is the most common and is available as either a low- or high-speed type. The low-speed anemometer generally is the most suitable for measuring the velocities in ordinary airways. For a rough check of the velocity in an airway, it usually is satisfactory to hold the anemometer by hand, positioning it in the center of the airway for 30 sec. However, the resultant error may be as high as 25% , and such a hand-held approach is unsuitable when accurate or reliable measurements are required. To obtain more accurate measurements, the proper procedure is as follows: 1) Since holding the anemometer by hand generally causes the instrument to read about 15% high, it is mounted on a 0.6-m (2-ft) extension rod. 2) The airway is divided into equal right and left halves. A 1-min traverse is used in each half, moving the anemometer smoothly up and down in a zigzag pattern so that the entire half is covered within the allotted minute. 3) The manufacturer's correction table is applied to the readings to adjust the velocity calculation as necessary. Whenever possible, anemometer readings should be obtained in a long straight section of airway that has a constant cross-sectional area. Bends and obstructions should be avoided, since they cause turbulence and other discontinuities in the airflow and can degrade the accuracy of the velocity measurements. Although a series of velocity measurements at one location usually corresponds to within a few percent, this is not an indication that the airflows calculated from those readings are completely accurate. One reason is that the correction table provided with the instrument generally is not for that specific instrument; instead, it represents the average correction for all such instru¬ments made by the particular manufacturer. Most cor¬rection tables specify a correction factor of from 0 to 15%, depending upon the velocity. However, even after correction, the instrument error still may range from 3 to 5%. At low velocities such as those below 0.76 m/s (150 fpm), the instrument error can be two or three times greater than this, ranging from 6 to 15%. The new ball-bearing anemometers generally perform somewhat better at low velocities than did the older conventional anemometers. Another source of error is introduced when measur¬ing the cross-sectional area of the airway or entry. Under the best of circumstances, measurement errors, instrument errors, and a host of other minor errors all combine to cause a total error of at least 10% in the velocity calculation. The vane anemometer also can be used with reason¬able accuracy to measure airflows in mine-ventilation ducts. In this application, the anemometer is mounted on a rod and is held at the center of the duct end. For a duct that is discharging air, the average velocity in the duct is 85% of the centerline reading (Northover, 1957). For a duct that is taking in air, the average velocity is 70% of the centerline reading (Haney and Hlavsa, 1976). To measure the airflow discharged from a regulator or from a small hole in a stopping or bulk¬head, a correction factor for the area is necessary. A good approach in this situation is to traverse the area of the regulator or hole, holding the anemometer with an extension rod. This provides an average velocity that is multiplied by 85% of the measured area of the regulator or hole. In all cases, the manufacturer's instrument cor¬rection table must be used and applied properly. For accurate results, the anemometer should be returned to the manufacturer for periodic cleaning and checking. If it is in daily use, the anemometer should be returned about once per year, and proportionally less frequently if the usage is less frequent than on a daily basis. Smoke Tube The smoke tube may not appeal to individuals who believe that good measurement results can be obtained only with expensive, complicated, and fragile instru¬mentation. Nevertheless, smoke works about as well as anything for the routine measurement of low air velocities in mines. The following procedure yields reasonably good results: 1) Two marks are scratched 7.6 m (25 ft) apart on the floor of the airway. 2) The smoke tube is used to release a cloud of smoke in the center of the airway, about 0.9 m (3 ft) upstream of the first mark on the floor. 3) A timed interval begins when the leading edge of the smoke cloud passes over the first mark, and the interval stops when the leading edge of the cloud passes over the second mark. 4) A factor of 20% is subtracted from the cal¬culated velocity to determine the true average velocity, providing a correction for the centerline and for the spreading effect at the front of the cloud. Velocities calculated with the preceding method generally are accurate to within 10 to 15%. In some instances, the cloud from a conventional smoke tube

Jan 1, 1982

By T. P. Meloy

In the last decade increased and prolonged interest has been displayed in the use: of tunneling or rapid excavation to solve many of the urban and industrial problems confronting our society. There has been talk and action on the interurban rapid transit systems for major cities, and even preliminary designs for a Boston to Washington interurban transit system. Much of this interest stems from the search to the solution of our increasingly complex urban problems, where the surface area must be given over more and more to the inhabitants, and the subsurface for transit, utility and other services. While tunneling is not a panacea to urban ills it holds a real solution to many existing problems. There is also, among the tunneling experts, a growing confidence that technical problems of rapid tunneling can be solved. To solve these problems, R & D money must be invested. If it is to be money invested either by private industry or governments, there must be significant returns on the investment to justify the research and development need to bring about the breakthrough that will make tunneling a major contribution to the solution of urban problems. To make these economic studies more extensive and more accurate tunneling demand figures were needed. To this end, the Organization of Economic Cooperation & Development - OCED - included in its Conference on Tunneling a section on tunneling demand. As a result of the conference the organization for Economic Cooperation and Development issued a report entitled "The Advisory Conference on Tunneling - Report on Tunneling Demand 1960-1980. " This report was presented at the OCED Conference on Rapid Excavation, held at Washington, D.C. To obtain the data in the Report, questionnaires were sent to the OCED countries and 18 replies were received from Australia, Austria, Belgium, Canada, Denmark, France, Germany, Ireland, Italy, Japan, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom, and the United States. While it is true, that data were missing, that sometimes the definitions were confused, and that several countries provided no cost estimates at all, in general, this report contains the most comprehensive gathering of data that ever existed in the field. All data in the OECD report is expressed in terms of meters or cubic meters, and costs are in U.S. dollars.

Jan 1, 1970

By William A. Turcotte

Introduction The need for water is fundamental to every minerals processing operation. Though this may sound rather elementary, it is one area that cannot be over- looked. Frank C. Quinn in his paper entitled "Water Is Water Is Water" (1967) said, "but it isn't as simple as that. Very often research is slowed down and production is hampered because of a lack of appreciation for the behavior of water." The quantity of water needed for any operation is determined from bench and pilot plant testing. The quality required by the process for both fresh and reuse water is also established during these two testing phases. Quinn's statements are true whether the process involves the paper industry, the minerals industry, or any other industry. It is not the author's intent to cover water quality, quantity, or re- cycle in specific terms, but to provide the reader with a general outline of the topic with reference to several valuable sources of information. The first part of the chapter will cover several of the areas that have been de- tailed by others and also provide a list of reference sources. The references at the end of the chapter are not all inclusive but will provide a good starting point. In the second part of the chapter, a detailed description, with flowsheet illustrations, is pro- vided on the evolution of the reclaim (reuse) water system at the Tilden concentrator. Mineral Industry Water Needs Beresford and Edler (1978) surmnarized the minerals industry's need for water this way: "minerals are necessary to a modern complex technological society. The minerals industry, while its water needs are relatively minor compared to large users such as agriculture, nevertheless requires a large quantity of water to carry out daily operations from mining to final product refining." In 1973 total water use in the United States was estimated at 15.14 billion cubic meters (4 trillion gallons) for the minerals industry. Of this, about 69% was recirculated within the system. In 1982 Watt and Horton stated that the percent of recycled water in the minerals industry had improved to 73%, showing the minerals industry is an efficient user of water and that steady improvement in water recycling is something the minerals industry can look to with pride. The percent of water needed by the United States' minerals industry was estimated in 1962 to be about 2% of the total water required by industry

Jan 1, 1986

By D. F. Symonds

INTRODUCTION Dense medium processes have been used to separate coal and ores for over a hundred years. In fact Sir Henry Bessemer first patented a process in 1858. In recent years, their importance relative to other gravity dependent processes has increased. This is particularly true in the coal industry where over 60% of all preparation plants operating in 1984 in North America (1) contained either dense medium vessel or cyclone circuits. In addition, the stringent product quality demands of the consumer, together with increases in mining costs, dictate that the cleaning circuits be both predictable and efficient. Dense medium systems are the most predictable and efficient of all gravity- dependent processes. The majority of the text of this chapter will be concerned with dense medium applications as they relate to the coal industry. However, the techniques and calculation procedures can be applied, in general, to all non-coal minerals (such as diamonds, marginal iron and lead-zinc ores and gravel) which take advantage of a difference in specific gravity between the saleable product and the reject. The object in dense medium cleaning is to produce a liquid whose effective specific gravity is between that of the concentrate and the reject. In which case the lighter product will float to the surface and the heavier product will sink to the bottom. Unfortunately, this simple process becomes complicated by the following practical necessities: (a) collecting and removing the float and sink products from the medium without disturbing the free settling effects; (b) maintaining and controlling the specific gravity of the medium; (c) separating and reclaiming the medium once the products have left the separating vessel; and (d) separating finer sized particles which take longer to fall through the dense, and often viscous, medium. As a result of the last issue (item d) two main types of dense medium separators have evolved: dense medium vessels and dense medium cyclones. Dense medium vessels are essentially large baths through which the dense medium flows at a relatively slow velocity. The lighter products float to the surface and are carried out of the vessel by the medium flow. The heavier products sink to the bottom of the vessel and are physically transported out either by means of a conveyor (usually a chain conveyor) or a rotating, lifting arrangement (Figure 1). They generally

Jan 1, 1986

By S. J. Czehura

The Butte quartz monzonite is the host rock for early porphyry copper style mineralization and subsequent mesothermal-epithermal, enargite-gold style veining that transects the district. The east-west Anaconda system veins: including the Emma, Anaconda-Original, Syndicate, Badger-State, and Alice-Rainbow veins, each with strike lengths of over 12,000 feet and vertical continuity in excess of 4,500 feet, along with mining widths from 5 to 50 feet, are unique to Butte. The incredible dimensions and tenor of these veins have yet to be surpassed and Butte is still touted as being the “Richest Hill on Earth.” The Anaconda Company was formed in 1895 to develop underground copper reserves in the district and eventually consolidated all operations under one company. Production from underground mining continued through the mid-1970’s. Open pit mining in the Berkeley pit began in 1955 with the extraction of supergene ores, along with the remnants of deeper horsetail zones inaccessible to the underground mines. Operations in the Berkeley pit were suspended in mid-1982 because of the rejection of high arsenic, copper concentrates at major smelting facilities throughout the world. Bulk mining of porphyry style mineralization in the Continental pit began in January 1980 to supplement copper production while stripping “C” pushback in the Berkeley pit. The Anaconda Smelter closed in September 1980. A molybdenum circuit was added to the Butte Concentrator in 1981 and mining continued in the Continental pit to produce copper and molybdenum concentrates. A blend of Berkeley and Continental ores were processed to dilute penalty metals in the final concentrates marketed to toll smelters. All mining operations ceased mid-1983 when Anaconda closed the Continental pit and offered the property for sale. Montana Resources reopened the Continental pit in June 1986 to produce copper and molybdenum concentrates. Operations were suspended mid-2000, because of exorbitantly high power prices, but resumed in November 2003 with rising metal prices. Bulk open pit mining of the early porphyry style mineralization has sustained production over the past twenty years and mining is expected to continue in the Continental pit with favorable prices. Future mining will eventually develop a 500 million-ton geologic resource incorporated in a supergene enrichment blanket situated between the Berkeley pit and the Continental pit. Grades in this enrichment blanket range in the neighborhood of 0.5% copper.

Jan 1, 2006

By William J. McCloy, Robert L. Gamble

A coal-fired fluidized bed steam generator rated at 12.6 kg/s has demonstrated the industrial and institutional application of fluidized bed combustion by burning high sulfur coal in an environmentally acceptable manner within a populated area. Designed to provide steam for heating and cooling, the unit was placed into service at Georgetown University in Washington, DC, and has already logged 5275 hours.* The unit has consistently operated well within Washington's strict regulations governing emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), and particulates. The Georgetown program, cofunded by the university and the US Department of Energy, has shown that fluidized bed combustion is a promising way to realize the full potential of coal, the nation's most abundant energy resource. In a fluidized bed steam generator, a layer of granular limestone is placed on top of a grid designed to prevent particles from falling through. Air is passed upward through the bed with sufficient force to lift and float the particles. At this point the bed material resembles a boiling liquid. Crushed coal is then introduced into the bed and ignited. When high sulfur coal is burned, limestone absorbs the SO2 produced. The operating temperature of a fluidized bed steam generator is relatively low (approximately 871°C). As a result, NO, formation is minimal. Another potential problem encountered in burning coal is fly ash, a form of particulate. A feature of the fluidized bed design, developed by Foster Wheeler Energy Corp., is a fly ash reinjection system. Fly ash is reintroduced into the bed where it is burned again, thereby enhancing fuel efficiency. Nearly all remaining fly ash is captured by a baghouse dust collector. At Georgetown, the fluidized bed steam generator and all auxiliary equipment are enclosed in a structure aesthetically compatible with the surrounding university complex. The steam generator has two separate beds that can be fired independently, and operation to date has been with one and two beds in service, based on steam load demand. During several operating periods, when the fluidized bed unit was the only boiler in service, it supplied all the steam required by the 18.5 hm2 of buildings on campus. Initially fired with low sulfur coal, the unit was quickly switched over to higher sulfur fuel which will be used most of the time.

Jan 3, 1981

By S. W. Arambur

INTRODUCTION "Mujeres Roca" is a program developed by OMA in association with the Chamber of Commerce Canada Peru inspired in “Women who Rock”, a Canadian initiative to promote a greater participation of women in the mining industry. The program includes a coaching workshop called “Kallpa Warmi”, that means “Woman Strength”, to reinforce basic skills and values and 8 mentoring sessions with top executives of the mining industry who share their experiences and knowledge with a group of 10 selected young professional women from around the country. HISTORY OMA is a nonprofit association founded in 2014 dedicated to contributing to the education of low-income university students with high academic performance in careers related to mining and earth sciences. Our mission is to empower the future professionals by strengthening their soft skills and enhancing their capacity to become leaders and agents of change in their own regions. The Chamber of Commerce Canada Peru has a long-standing commitment to gender equality and promotes women participation in male dominated industries. As it is well known, the mining sector is and has always been key to Peru’s economy, representing about 10% of the country’s GDP. Thus, mining can contribute significantly to our economic development and we believe that women can make a positive difference. A study prepared by PwC and "Women in Mining” provided indicators on the advantages that mining companies have when including women in their executive’s positions. These indicators sustain that when a mining company includes women in its management staff, its net profit increases by 6%. This information clearly shows that women participation is not only a matter of human rights and gender equality, but of productivity and profitability. Nevertheless, the mining sector has the fewer number of women on boards of any industry group in the world. Having this in mind, OMA decided to expand its activities and create together with the Chamber of Commerce Canada Peru, the program “Mujeres Roca”, in order to inspire and attract young women to the mining sector, a traditionally masculine industry. The program also aims to encourage mining companies to more actively recruit and keep women in their boards. The program was launched in 2016 within the framework of EXPOMINA PERU, the largest international mining exhibition that take place in Lima every two years.

Jan 1, 2019

By Jan M. Mutmansky

30.1-THE SCOPE OF SYSTEMS ENGINEERING JAN M. MUTMANSKY JAN M. MUTMANSKY 30.1.1-DEFINITIONS The terms "systems engineering," "systems analysis," and "operations research," common in today's technical literature, often are interchanged because of their similar meanings. However, some differences exist which need explanation. The most convenient way to achieve an understanding of the differences is to start with the definition of a system, namely, a collection of components which interact in a specific manner to accomplish a common objective. Accordingly, a haulage truck, a computer, a missile, a mining company or a nation each may be considered a system. Systems engineering generally can be defined as the conception, planning, design and engineering of any system of interacting elements so that the objective of the system is automatically optimized. Thus, systems engineering normally is con¬cerned with systems not yet activated.',' Systems analysis may be described as a scientific method of making decisions based on a quantitative or other objective evaluation of all action alternatives. It is very similar to systems engineering but usually is not considered to be restricted to problems of design prior to use. While the previous two disciplines are somewhat vague and can encompass a great variety of engineering functions, operations research can be more specifically defined as the application of mathematical models to the problem of optimizing the objective of any predefined system. Systems analysis and systems engineering are closely aligned sciences but opera¬tions research differs in the following ways. First, it generally is associated specifically¬with optimization and mathematical models while the other two often are not. In addition, it, is used predominantly on well-defined problems which can be ex¬pressed in mathematical terms. However, systems engineering or systems analysis may deal with highly complex social or governmental systems which may be ill¬defined and unsolvable by the classical methods of operations research. Finally, systems analysis and engineering always strive to look at the entire system to avoid the problem of suboptimization often necessary in operations research because of the necessity for a mathematical model. Because of his more extensive system, however, the systems engineer often is less able to find the optimal system. In summary, operations research, systems analysis and systems engineering are very similar in purpose but one, operations research, is more mathematical in nature and forms an important part of the other two activities. Other definitions which may be helpful are provided by Griffiths 3 Wilson,4 Falkic 5 Hall,2 Quade and Boucher, 6 and Flagle et al. 1 30.1.2-METHOD AND TECHNIQUES The systems or operations research approach makes use of scientific problem solving. The basic procedure comprises the following general steps: 1. Definition of the problem. 2. Construction of a model of the system. 3. Testing of the model under known conditions.

Jan 1, 1973

By Peter T. Luckie, Joseph W. III Leonard

INTRODUCTION In a bed of fine coal, water can be found in the interstices created by the particle surfaces and in the pores within the coal particles. The extent of the interstices voidage is obviously a function of the particle sizes and morphologies, as shown by the fact that the bulk density of coarse coal is greater than that of fine coal. After drainage, the voids can be completely or partially filled. By increasing the suction pressure across the bed, as is done in vacuum filtering, the quantity of water in the voids can be reduced. But eventually the increased suction pressure has little influence on the moisture reduction. In addition, the moisture in the pore structure of the coal is unaffected by the mechanical removal of the moisture in the interstices. When this condition is reached, the total moisture content of the coal can only be reduced further by evaporating the water. Evaporative drying is done for one or more of the following reasons: 1. To avoid freezing difficulties and to facilitate handling during shipment, storage, and transfer to the points of utilization. 2. To reduce the heat loss due to evaporation of the moisture from the coal during the combustion process, thus increasing heating efficiency. 3. To decrease transportation costs. The heating value of coal is equally improved for each percentage point reduction in the noncombustibles in coal. It is estimated that a reduction of 1%22 in the total moisture in the coal increases the thermal efficiency of the heat-raising process by about 0. Some coal buyers consider 1 % moisture content to be the equivalent of a 4% ash content.23 It is important to avoid drying the coal to too low a moisture level, since the complete removal of surface moisture to produce a bone dry product can result in a serious dust, wind lost, and safety problem. Surface moisture con- tents of 3% or less for shipped coal are not uncommon. However, the evaporatively dried coal may be lower, Y, to 1%, since the mechanically dewatered coal may be higher. Evaporatively dried coal can be treated (sprayed) with chemicals in order to control the dustiness and any freezing difficulties, thereby providing the producer with more operational flexibility. The evaporative drying of coal is essentially a process of simultaneous transfer of energy, usually in the form of heat, and water, in the form of vapor, from the coal. In order to remove the undesired moisture, it is necessary to raise the temperature of the water from the entering temperature of the feed stream, TF, to the boiling point of the water (usually taken as 212"F), vaporize

Jan 1, 1991

By S. Fairis Samuelson

Boling Dome. a piercement salt dome in the Texas Gulf Coast basin is (was) the single largest deposit of native sulfur in the Western world. Total sulfur production has been over 81.000,000 long tons and the mine is still in production. Data from over 60 years of operation and 8.000+ wells reveal a salt dome rich in history as well as minerals. Sulfur mineralization and production correlate well with caprock structure and morphology. The occurrence of Mississippi Valley-type deposits in fracture zones is notable in some areas and may warrant additional study. DISCOVERY AND PRODUCTION HISTORY Boling Dome is located in the south- east corner of Wharton County, Texas, 60 miles south-west of Houston. It is a piercement type dome in the Houston diapir province. It was discovered in 1922 when the county surveyor noticed sour gas seeps along the San Bernard River (Haynes. 1942). Several companies including Gulf Production Company. Humble, Texas Company, Sun and others quickly began drilling for oil and gas. Traces of native sulfur were reported in cuttings from many wells penetrating the caprock, but the first commercial quantities of sulfur were not found until Gulf Production's E.M. Chase 3 and 4 wells were drilled in 1927. Texas Gulf Sulphur, then mining sulfur at Gulf Dome in Matagorda County, secured the sulfur rights from Gulf for $3 million in cash and half of the profits after expenses for development and construction of plant and townsite were met (Haynes, 1942). The drilling results from 200 or so Wells revealed a massive deposit destined to become the largest single source of native sulfur in North America. Original reserves were estimated at just over 46 million long tons and were increased in later years. Production by the Frasch method was begun by Union Sulphur in 1928, and continued by Texas Gulf Sulphur Co. in 1929, and Duval Sulphur Co. and the Baker Williams Co. in 1935. Union produced 8,009 long tons, Duval produced 571,123 long tons, and Baker Williams produced 1,453 long tons. Through its deal with Gulf, Texasgulf acquired the largest and best mineralized portion of the dome and has produced 88,544,466 long tons through 1990, and production is planned for several more years. That amount of sulfur is equivalent to a cube measuring 1,152 feet on each side, or a sulfur highway 1 foot thick, 20 feet wide and 14,479 miles long. Peak production averaged 8,376 ltpd in 1948. A price war between North American sulfur producers and Mexican sulfur producers in 1956, followed by the recession of 1957 and 1958 (Haynes, 1959) coupled with a rapid increase in mining depth to below 700 feet began a gradual production decline that was never reversed (Figures 1 and 2).

Jan 1, 1992

By J. F. Mack, P. R. Michael, J. M. Shapaka, S. J. Self, M. W. Richmond

"On October 11, 2000, an estimated 306 million gallons of water and coal waste slurry drained from an impoundment in Martin County, eastern Kentucky into an adjacent underground mine. Approximately 230 million gallons of the water and slurry discharged from two underground mine portals and affected over 75 miles of streams in Kentucky and West Virginia. In response to this and several other similar events, the U.S. Office of Surface Mining Reclamation and Enforcement (OSMRE) commissioned an oversight study that evaluates how well state and federal regulatory programs established under the Surface Mining Control and Enforcement Act are ensuring that impoundment operators are minimizing the potential for impoundment-basin breakthroughs. The study focuses on slurry impoundments constructed in the hollows of Appalachia where numerous coal seams and steep topography combine to result in a large number of mined seams intersecting and underlying impounding facilities. Factors under consideration include: (1) full accounting of all mineable coal seams intersecting and underlying the impoundment; (2) identification and accurate location of underground mines close enough to the impoundment to potentially affect its stability; (3) assessment of the stability of coal barriers between the impoundment basin and adjacent mines, and stability of roof rock and pillars in mines subjacent to the structure; (4) determination of the flowability of the impounded slurry when expanding or undermining the facility are being considered; and (5) measures undertaken to reduce breakthrough potential when necessary. The oversight study began in 2012 after program-evaluation criteria were defined in an OSMRE technical position paper. The study is scheduled to be completed in 2017. BACKGROUND The Surface Mining Control and Reclamation Act (SMCRA) authorizes the disposal of coal mine waste by constructing a coarse coal mine waste embankment across a valley and pumping the fine coal mine waste (slurry) into the resulting basin (Figure 1). A concern shared by many engineers, geologists, and mine inspectors familiar with coal mine waste slurry impoundments is related to the common occurrence of underground mine workings adjacent to or beneath the impoundment: the potential for slurry “breakthroughs” into mine works and subsequent breakouts into the surface waterways (Figure 2). On October 11, 2000 a combination of coal refuse slurry and water from the Big Branch impoundment in Martin County, Kentucky broke through into an underground mine and subsequently discharged into the receiving streams. The location of the point of breakthrough, pathways of slurry/water flow within the mine workings, and two points where the liquid exited the mine are shown in Figure 3. An estimated 306 million gallons of water and coal refuse slurry drained from the impoundment into the adjacent underground mine. Approximately 230 million gallons subsequently discharged from the underground mine at two portals."

Jan 1, 2015

By D. T. Iseley, David Bennett, Christopher Norris

The microtunneling test program is one of three main elements of the research project, "Trenchless Construction: Evaluation of Methods and Materials to Install and Rehabilitate Underground Utilities." The other elements of this project include an evaluation and demonstration of horizontal directional drilling technology and pipeline rehabilitation systems. The research is a Corps and Industry cost-shared project funded under the Construction Productivity Advancement Research (CPAR) program. The laboratory partner is the U.S. Army Engineer Waterways Experiment Station (WES), Geotechnical Laboratory. The industry partner is the Louisiana Tech University's Trenchless Technology Center. Industry participants are contributing over half the total cost of this research. The overall objective of the CPAR program is to improve productivity in the U.S. construction industry, thereby enhancing the competitiveness of the U.S. industry in domestic and overseas markets. The Corps and other federal and state agencies will benefit by realizing reduced costs, enhanced safety and better products and services as the products of this research program are developed, tested, and pushed into the market place. The microtunneling demonstrations and evaluations were performed during September and October 1992 at a specially constructed test facility built at WES in Vicksburg, MS. The test facility is 104 m (340-ft) long, 5 m (16-ft) wide, and 4 m (13-ft) deep. It was constructed, ironically, by first excavating a trench into which 6 different types of soils were placed and compacted in approximately 18.3 m (60-ft) long sections. The soil profiles include a lean silty clay (loess), a dry sand, highly plastic buckshot clay, wet sand, clay gravel and silt. The interfaces between soil profiles were sloped to simulate mixed face conditions as the machines exit one zone and enter another, and provided challenges to ground control and alignment and grade control during these transitions. Moisture and density tests were performed on all materials in each lift to assure uniformity. Horizontal inclinometers and 3 levels of settlement plates were installed at key locations in the test bed. The settlement plates and rods and the horizontal inclinometers, together with surface survey points, provided data to evaluate settlement and heave along the test section. Penetration resistance was measured in each section of the completed test bed. Strain gages were installed in 8 of the 0.6 m (24 in.) diam. Hobas pipe sections to measure strains in the pipe as it was being jacked into place. Steering jack loads, jacking thrust loads, and cutterhead torque were also measured during the drives. The results of these tests will be used together with other information to develop guidelines for conducting feasibility studies and selecting proper methods compatible with anticipated conditions.

Jan 1, 1993

By Anna Sieminska-Lewandowska, Monika Mitew-Czajewska

"The construction of 6.3 km long central part of 2nd metro line in Warsaw was completed in September 2014 (7 stations - out of which three 25m deep stations - built using cut and cover method; two single-track tunnels constructed using four EPB TBMs as well as a short NATM section with soil freezing below the existing road tunnel). Central section of the 2nd metro line was opened to public after verification and testing in March 2015. Design and build tender for the extension of this line in East (three stations) and West direction (three stations) was announced with total length of running tunnels – approx. 5 km. Detailed description of a very complex geotechnical context, different construction methods, challenges encountered and solved during construction and finally lessons learnt on this interesting project are presented in the paper. DESCRITPTION OF THE PROJECT Introduction The very first concept plan of the metro system in Warsaw was designed several years after regaining independence by Poland in 1918. In 1929, following the geotechnical survey, design works begun, but the economic crisis of the 1930s stopped it. After a few years of break, in 1938 a coherent concept of the metro network was proposed to be implemented in phases over the next 35 years. In total, construction of 46 kilometers of metro, including 31 km of tunnels and 15 km on surface, was planned. Unfortunately, World War 2 made the implementation of those plans impossible. In the post-war period several metro designs were elaborated, but none except one was scheduled for implementation. Construction of the 1st, 23.1 km long, North-South line commenced in 1983 and finished in 2008 (Sieminska-Lewandowska et all. 2009). Nowadays, Warsaw covers the area of 517 km2 and, according to year 2014 statistical data, the city has much more than 1.7 million inhabitants. Only one operating metro line is not sufficient for such a populated city. Up-to-date metro plan, shown on Figure 1, includes also 30.5 km long 2nd metro line. It’s route is divided into four sections: Western Section with the length of approx. 9.2 km and 9 stations, Central Section with the length of 6.3 km and 7 stations, North-East Section with the length of 7.7 km and 6 stations, South-East Section with the length of 7.1 km and 6 stations. The construction of the central part of the 2nd metro line in Warsaw was completed in September 2014 and its operation started in March 2015. The paper focuses on challenges encountered and solved and lessons learnt during construction of the central part of the 2nd metro line in Warsaw."

Jan 1, 2016

By D. R. Dixon

Since the critical role of oxygen in xanthate flotation of sulphides was established (1) subsequent studies have been concerned mainly with the galena-xanthate system. It is therefore surprising to find at the conclusion of a comprehensive review of the topic by Granville, Finkelstein and Allison (2) that it was not possible for them to draw unequivocable conclusions on the mechanism of xanthate adsorption. It was apparent that some new advances were likely if systems other than galena-xanthate (Pbs/x-) were examined. (2) Specifically a less reactive sulphide such as ZnS may interact with flotation reagents at a slower rate than PbS and more information per unit time gathered. Again ZnS is far less reactive electrochemically than PbS or stated equivalently, it is a poorer semiconductor than PbS. More importantly, the ability of ZnS to act as a semi-conductor can be controlled photochemically rather than by direct doping reactions for which it is difficult to assess the uniformity of doping. Thus the conductivity of ZnS can be made the same as that of PbS by irradiating the ZnS with ultraviolet light at circa 360 n.m. (3)

Jan 1, 1974

By Rodolfo V. de la Cruz

This paper describes the development of a new method and device for determining the in-situ mechanical properties of rock masses. The method involves a self-recording mechanical deformation gauge for sensing-recording she deformation of the borehole wall when loaded hydraulically. The self-recording feature of the gauge eliminates the difficult technical problem of transmitting signals over very long cables for measurements at great depths. Adopting a mechanical gauge instead of electronic, electrical, optical or grid techniques eliminates delicate instrumentation and installation problems. Moreover, mechanical gauges are inherently rugged and suitable for use in severe borehole conditions including very high temperatures. The technique was tested in limestone, basalt and granite specimen. The calculated mechanical property values for 1 the tests agree with those obtained by conventional testing methods. The self-recording mechanical deformation gauge has a minimum reading of 50 micro inches (1.27 x 10-3mm), comparable with electrical resistance strain gauges, capable of reading deformations over a range of 0.25 inches (6.35mm). The sensitivity, ease and accuracy of the method recommends it highly for in-situ rock modulus measurements.

Jan 1, 1980

By E. W. Bauman

The important role that mineral aggregates assume today in the construction and chemical industries is best attested to by the astronomical tonnage figures for the annual production of aggregates in the United States as reported by the U. S. Bureau of Mines in their "Minerals Yearbook." For 1965, latest publication available, the tabulation shows a total of 1,716,000,000 tons made up of 30,000,000 slag, 908,000,000 sand and gravel, and 778,000,000 crushed stone. A much more favorable statistical position for slag can be established by listing the world-wide tonnage. According to Dr. A, W. Lee, Director, British Slag Federation, in a paper presented before the 8th Annual conference of the British Institute of Works and Highway Superintendents, he estimates that the probable world consumption of slag is in the order of 100,000,000 tons showing--Great Britain with 10,000,000 tons, Germany, 15,000,000 tons, France, 1$000,000 tons and the United States with 30,000,000 tons. Thus it is seen that the United States accounts for almost one-third of the world's consumption of slag and the 3 west European powers another third.

Jan 1, 1967

By L. Adler

A fairly complex analysis is required to select, or evaluate a piece of excavating and bulk handling equipment and obtain its performance. At present there is little agreement as to what specific points should be considered, and even less on what procedure to follow. This paper provides both of these in a consistent and direct form. The analysis applies to all types and sizes of equipment from the bulldozer and the continuous miner, to the B.W.E. The importance of the equipment characteristics, job activities, and work conditions are stressed and separate analytical stems are established in a flow chart for these. They are combined using suitability tests in the following steps: 1) problem statement, 2) natural conditions, 3) suitability guidelines, 4) appropriate equipment types, 5) operational activities, 6) encumbered space, 7) geometric design, 8) equipment sizing, 9) failure and limits, 10) performance and consumption, 11) public policy checks, and 12) costs and profitability. Public policy and economics while considered throughout receive emphasis towards the end. The procedure is iterative, containing distinct feedback loops. Specifying the steps and sequence provides a necessary structure which has long been overdue.

Jan 1, 1983

By J. D. Goodrich

Success of The Carter Mining Company's safety program can be primarily attributed to "total immersion" of all operating and staff personnel in program design and implementation. Currently, the Company operates two surface coal mines in Campbell County, Wyoming. Total employment is about 440 and current annual production is about 15 million tons. The safety program has evolved from one which was administered primarily by staff personnel (the Safety Department) to one which requires active participation by line management and operating personnel. Lost time accident frequencies have declined from a high of 1.86 per 200K hours worked in 1978 to zero in 1982. Reportable accident frequencies have declined from slightly over 5 to slightly over 2 during the same period. Analysis of program results indicates that the most important achievement by the company has been to gain strong commitment to safe operation by all employees. It is important that program format and content be frequently changed and modified so that: 1) The requirement for safe job performance is communicated well and often, 2) The safe job performance message is trans- mitted in new and interesting ways, and 3) Operating personnel participate in design and implementation of the program.

Jan 1, 1983

By W. G. Miller

A series of computer programs for the analysis and mapping of coal-related data has been developed at the Illinois State Geological Survey; these programs, known collectively as the Coal Data System, represent the latest achievements in computer processing of geologic data at the Survey. Building upon programs previously developed in the Survey's Computer Services Unit, they expand the scope of the computerized data base that the Survey has been using for analyzing coal-related data. The System was partially developed during a joint study by the Illinois State Water Survey and the Geological Survey entitled, ?Coal and Water Resources for Coal Conversion in Illinois.? 2 In that study the available coal reserves more than 42 inches thick in the two principal coal seams throughout the state were mapped. The System was used to calculate the coal reserves and to report the average number of tons of coal in place per square mile in each township (Figures 1 and 2). It also produced maps of the coal features of sufficient quality to be printed on material that was scribed as master copy for the printing of full-color 1:500,000 scale maps (see Figures 3 and 4).

Jan 1, 1975

By R. Jacobson

This paper presents comparison of proposed future solution and in-situ mining methods for in-situ leaching and recovery of uranium, gold, silver, and copper. We propose to show that in the future new extraction methods for each metal will eventually evolve for each hydrometallurgical process step, i.e. in-situ leaching, recovery, and concentration; precipitation and reduction; and drying, when required--without generating waste or bleed streams. In the future, to be highly profitable, these forms of mining will develop into an integrated system to eliminate waste streams using safe, powerful lixiviants. This integration will include, with some exceptions, improvements in the following areas of process development: 1. Lixiviant selection and in-situ leaching technique, 2. Target metal recovery and concentration (at a surface hydrometallurgical facility) from the circulating pregnant lixiviant stream, 3. Target metal precipitation or reduction, where decant water from the precipitate dewatering step is reusable for resin or solvent strip liquor (eluant), 4. Final preparation of target metal for sales, i.e. drying, purification, casting, packaging, 5. Restoration where most of the groundwater restoration process is performed at the same rate as multi-wellfield mining.

Jan 1, 1987