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By Liu Cheng-si

Basing on a brief assessment of the conventional theory of ventilating air distribution, its methods of calculation and practical application, this paper makes an approach to the controllability of different aircourses of a ventilation network and further points out that it is possible for the positions of control to extent into the natural distribution subnetwork of the ventilation network, which was been long considered as a restricted zone. This important discovery makes the regulation of the ventilation system more flexible and diversified, thus attaining quantitative distribution of ventilating air as well as a cost benefit. Because it has been impossible to solve the problem mentioned above by conventional theory and its relevant methods of calculation, the author, based on applying graph theory on the structure, characteristics, and requirements of controllability of the ventilation network, presents a new controllable subgraph concept and the means for determining the rational quantity for control devices of the ventilation network. The solution of all the control alternatives and methods of obtaining all the parameters for the solution of various alternatives have been derived. The economic benefit and the optional positions of the control devices have also been approached. Specific calculation examples are a1 so included in this paper. Along with the conventional theory and its methods, it can be seen that the new theory presented makes a great change in the control aspects of the ventilation network, with the number of possible alternatives increasing in an astonishing manner. Among the alternatives, some may be safer, more economical or technologically superior than those obtained from conventional theory. Thus, the new theory may provide an immense improvement in the choice of a ventilation system.

Jan 1, 1987

By J. L. Roll

The Surface Mining Control and Reclamation Act of 1977 (SMCRA) and the regulations promulgated for that "Act" have resulted in changes to surface mining operations in order to comply with the stringent federally enforced reclamation requirements for prime farmland. In many instances the operator has modified surface mining operations to meet the prime farmland requirements through changes to mining equipment operation, addition of new equipment targeted for reclamation or the use of totally different mining techniques. The major challenge to mine operators has been how to use existing mining equipment to meet the requirements of the "Act." Freeman United Coal Mining Company opened the first new large surface coal mine in Illinois following passage of the "Act." The Industry Mine, located near Macomb, Illinois started mining operations during March of 1982 and was required therefore, to meet all of the requirements of the "Act" including prime farmland restoration. At the Industry Mine a shovel and a cross-pit bucket wheel excavator (wheel) are used for overburden removal and the wheel is addition- ally utilized to assist in reclamation operations. The wheel mines the subsoil thereby elliminating scraper placement of that subsoil and the attendant compaction problems with scraper placed subsoil. The wheel is used to convey topsoil stock- piles from the highwall to the mined overburden in order to lessen scraper traffic and possible compaction on the graded overburden during top- soil removal and replacement. Close control of the operation of the wheel yields more uniform wheel spoil ridges which then require less grading prior to topsoil replacement.

Jan 1, 1986

By Betty L. Gibbs

Before the first shovelful of dirt is removed from a developing mining property, a wide range of data must be collected, organized and analyzed. Among the key steps in this process are: • Visualization of the deposit from drill hole data and geologic interpretation, using all available information, including surface geology, geochemistry and geophysics. • Drawing of vertical and horizontal sections. • Construction of a 3D solid model of the deposit. • Contouring of deposit outlines and geological structure until the model represents best estimate of reality. • Estimation of grade and quality distribution. • Calculation of reserves. • Examination of possible mining methods. • Determination of economic feasibility. Many techniques are available to aid in this process of mine project feasibility analysis, from quick pencil calculations to sophisticated computer methods. However, time races faster in the complex modem business world than it did 50 years ago. Tried and true pencil methods take too much time. Opportunity may pass a mine developer by while a property is still in the first stages of analysis. In the days of hand techniques, initial analysis of the economic feasibility of a mining project usually stopped with reserve calculations and broad mine planning. Further planning was not done or was done only for the short term. Manual techniques require too much time and manpower to evaluate a longterm mining program. Mining-industry recognition of computer utility has increased. Most companies now use computers in technical applications and could not conceive of working without them. Building initial computer models of a deposit may take nearly as long as hand techniques. But the payback comes when changes are needed and a variety of mine plans are quickly tested.

Jan 1, 1990

By Michael L. Cramer, Kunsoo Kim

INTRODUCTION The Columbia River Basalt beneath the Hanford Site is one of several rock types being considered by the U.S. Department of Energy for the first commercial high-level nuclear waste repository. The Basalt Waste Isolation Project (BWIP) has been carrying out a comprehensive investigation to assess the feasibility of constructing a repository in basalt and to develop technology required for repository engineering and site characterization. Development of a nuclear waste repository requires a number of design considerations not usually necessary in the planning of conventional underground structures. Principal among these is the thermally induced stress field resulting from waste emplacement. This thermal stress, super- imposed on the preexisting in situ- and excavation- induced stress fields, needs to be evaluated in the design process due to the sensitivity of waste emplacement density to this factor. The nature of this thermally induced stress field is dependent on several factors, including the temperature distribution around the repository openings, the thermal properties of the rock mass, and the deformability of the rock mass. Re1iable performance of the repository structure is largely determined by the ability to under- stand the above rock mass characteristics and predict the underground opening response to waste emplacement based on this understanding. To gain an understanding of this rock mass behavior in a repository condition, the BWIP has conducted a large-scale heated block test in basalt at the Near-Surf ace Test Facility (NSTF) on the Hanford Site. This paper presents the results from the elevated temperature phase of the block test in which the thermal, mechanical, and thermo- mechanical response of the closely jointed basalt rock mass was evaluated as a function of stress and loading orientation at varying temperatures up to 200 oC. SITE GEOLOGY The NSTF test areas, including the block test site, are located in the entablature zone of the Pomona basalt f low. The Pomona flow entablature is structurally typical of most flows in the Columbia River Basalt Group in that it is characterized by long, undulating, polygonal columns up to 2.4 m in length. Columns vary from 15 to 30 cm in diameter, averaging about 20 cm. Over their length, columns can vary in dip by 150 to 200. The column structures are dissected by subhorizontal cross joints that are generally discontinuous and seldom cross columnar joint boundaries. Spacing of the cross joints also averages about 20 cm. A representative joint pattern taken from mapping of the tunnel wall near the block test site is shown in figure 1. Application of the Rock Mass Rating System (Bieniawski, l979) to the block test site yielded an overall value of 62. The corresponding value from application of the Q-system (Barton et al., 1974) is 8.7 (Cramer and Kim,1985). The NSTF is approximately 50 m below the surf ace. However, this depth is sti1l above the water table and conditions are generally dry. Interstitial water exists as the result of percolation of meteoric water from the surface.

Jan 1, 1986

By Edward J. Cording, William H. Hansmire

INTRODUCTION The Washington Metro, a rapid transit system that will serve the District of Columbia, Virginia, and Maryland, has been under construction for about two years. Construction of the Metro by the Washington Metropolitan Area Transit Authority involves a large amount of cut and cover, soil tunnel, and rock tunnel construction. To aid initial construction and improve future designs, performance observations were undertaken on tunnels in the initial construction phase. The University of Illinois Department of Civil Engineering was engaged to carry out a comprehensive program of field observations and measurements for this purpose. One part of the program was on the first soft ground tunnel constructed in the system. The tunnel is a 2200-ft (670 m) twin-bore section, designated Contract A-2, in downtown Washington. Two objectives of this program were to determine the relationship of construction procedure to settlements and to observe the pattern of soil movement around the tunnel as an aid in evaluating underpinning criteria for nearby structures. A test section, consisting t three instrument lines located across the tunnel path, was established prior to mining in Lafayette Park to measure in detail both vertical and lateral soil displacements as the tunnel was mined through the section. The site was selected because it is free from surface structures and access for installation and reading of the instruments was convenient. Load and distortion measurements on the lining were also made within the test section; observations of construction procedure were maintained throughout construction.

Jan 1, 1997

By J. D. Miller, J. Hupka

Environmental applications of the air-sparged hydrocyclone (ASH) technology are presented. The original ASH design used porous sintered steel or porous polyethylene tubes as spargers. To diminish/prevent plugging and to reduce pressure head loss in the gas path a wire screen sparger and new hydrocyclone design have been developed, which allows for wide application of the technology to solve environmental problems and to be used as a chemical reactor. Field and laboratory trials have shown that the ASH technology might be preferred for the stripping of volatile organic compounds WOC) from contaminated water. The ASH has also been developed for absorption of SO2, toluene vapors, and for the recovery of cyanide.

Jan 1, 2005

By Martin Herrenknecht

The world?s growing population and rapidly proceeding urbanization are boosting an enormous demand for new and high-capacity infrastructures to secure the mobility of goods and people. Densely populated areas face the challenge to provide efficient traffic infrastructure, such as a modern public transportation system. At the same time, the maintenance and modernization of supply and disposal structures for water, sewage, energy and communication are also essential. Additionally, supra-regional transportation routes such as long distance water diversion schemes are the challenges for the future. All these projects are as demanding as they are characterized by a tight time schedule.

Jan 1, 2010

By J. L. Goodier

The paper points up the hesitance of private capital to pursue development of offshore mineral mining endeavors due to the deterrent effect of the clouded legal status of such endeavors. Some states have no laws or regulations to protect the potential exploiter. Others have regulations which give no proprietary rights of exploration to mineral discoveries. The above factors and others are discussed and analyzed in some detail, covering, in turn, summations of the federal regulations and of each of the coastal states. Some comparative analyses are provided, and some recommendations for encouragement to capital investors are made.

Jan 1, 1968

By Robert M. St. Louis, Frank D. Wicks, John E. Huffman, Edward E. Maurer

The treatment of Mercur's refractory ores has been well published; however, the processing of the remaining semi-refractory or oxide ores has not been discussed. Although ore control at Mercur is efficient, refractory vestiges are left with the mill-feed, oxide ores. Also, these ores as mined are not necessarily completely oxidized at Mercur and should be termed semi-refractory ores. This paper will discuss those steps taken at Mercur to enhance the recovery of gold from partially oxidized ores at Mercur. The Mercur mill is a conventional SAG/ball mill grinding circuit feeding a GIL plant. The circuit has been well published and will not be further reviewed.

Jan 1, 1990

By John H. Paugh

Hydraulic slurrying and pumpability characteristics of phosphate matrix (ore) have not been quantitatively defined. An elemental triangular diagram analysis of rock/sediment texture is used to classify the nature of the ore; then related to empirical field data of hydraulic pressureand production yardage ratios. This experiment is applied as a geotechnical tool to provide empirical data of ore slurry and pumpability characteristics as key considerations in the design of slurry pipeline systems. A real texture variability maps are developed on a section of land to assist mine engineering planning.

Jan 1, 1981

By M. Adnan Göksel

Pyrite cinder is generated by roasting pyrite for sulfur dioxide production. It contains up to 62% iron, but also may contain other hazardous or toxic materials such as Zn, Pb, As, T1, Cd, Cu, Sn and S. Furthermore, the physical characteristics are not properly suited for conventional sintering. As a result pyrite cinder is considered to be unsuitable for iron and steelmaking or for outside storage because of its potential for causing environmental problems. In recent years industrialized nations have put increasing pressure on the manufacturers to either use such waste products or properly dispose of them. In this study, solutions to both the iron recovery and disposal problem were attempted by pelletizing the pyrite fines with internal carbon. The pellets, after hydrothermal hardening, were reduced and melted in a furnace for hot metal production. Hot metal of usuable quality was produced and the hazardous materials were either collected with the fumes or in the slag.

Jan 1, 1984

The Mesquite mine is being operated by Gold Fields Operating Co.-Mesquite, a subsidiary of Gold Fields Mining Corp. The mine Is located in southeastern California about 56 km (35 miles) east of the farming community of Brawley, California. The mine has been in commercial production since early 1986 and Is a conventional open pit mine developed on 6.1 m (20 foot) benches. The gold is recovered by heap leach using permanent heaps built in multiple 6.1 m (20 foot) lifts. This year's gold production will be in the range of 5,600 kg (180,000 troy ounces). Current ore production is about 18,140 tonnes (20,000 tons) per day while the total tons mined Is averaging 65,000 tonnes (72,000 tons) per day. The climate at the mine is extremely arid with rainfall of 7.6 cm (3 inches) per year. From early May until late October daytime temperatures generally exceed 37.8 degrees Celsius (100 degrees Fahrenheit) and can be as high as 37.9 degrees Celsius (120 degrees Fahrenheit).

Jan 1, 1989

By Donald G. Dahle

Project Payette is a conceptual nuclear experiment under the Vela Uniform program intended to further evaluate the mechanism of seismic decoupling. Vela Uniform is a Department of Defense program to improve this country's capability to detect, locate and identify underground nuclear detonations. This program evolved from recommendations of the Panel on Seismic Improve¬ment, (Berkner Panel), an officially appointed group of noted U. S. scientists. This Panel, taking note of difficulties in detecting the differences between some underground nuclear detonations and some earthquakes recommended a program of increased basic research in seismology. The theory of decoupling, Which involves possible reducing of seismic motion resulting from underground explosions by reducing the coupling or physical linkage between the explosion and the geologic environment, was investigated by Dr. Albert latter and his associates at RAND during the late 1950's. The concept has been further investigated theoretically by scientists of the Lawrence Radiation Laboratory and the Sandia Laboratory. The theory has been tested experimentally under Vela Uniform Projects Cowboy, Dribble and Sterling. The Salmon Event of Project Dribble was a tamped (with the explosive in firm contact with the geologic formation) nuclear detonation 2700 feet below ground in the Tatum Salt Dome. Project Payette, if found to be feasible and if authorized for actual execution, would become a decoupled experiment in the same environment.

Jan 1, 1968

By Marco Sonnenschein

As time is costly, engineering companies have developed methods, procedures and mechanical equipment to tunnel faster. But the best excavation method will not be able to cope with the time pressure if there is not a reliable backup system. Therefore, the application of belt conveyors for tunnel boring machine (TBM) drives as well as for drill-and-blast driven tunnels assure a quick and smooth removal of excavated soil in order to enhance the efficiency of the tunneling equipment. During the last 10 years, belt conveyor systems have achieved ?state-of-the-art? levels and have become the first choice for muck removal systems in both TBM and drill-and-blast driven tunnels. Because time has become such a key criterion in tunneling projects, it is essential that all equipment is operated so as to derive optimum efficiency and minimize costs. Efficiency also means to think about new tasks for existing technologies.

Jan 1, 2012

By Vishnu S. Gupta

A modular computer program APEX (AMAX Process Evaluation Executive), has been developed at AMAX Extractive R&D, Golden, Colorado to facilitate rapid simulation of steady state material and energy balances of existing and/or proposed metallurgical process flowsheets. Currently, APEX is being used for the design, analysis, and evaluation of several of AMAX?s Nickel, Molybdenumand Tungsten processes. A unique feature of APEX is that it allows specifications of flow rates and compositions for different solid size fractions in addition to aqueous organic and gaseous phases. Thus, a metallurgical process which may involve crushing, grinding, flotation, leaching, washing, solvent extraction, precitation and refining operations can be simulated in a single computer run using APEX. APEX requires two input data files. The first is a process data file which includes physical and thermodynamic properties of the various chemical components of interest. This data file is unique to the process under study and does not require changes for alterations in the process flowsheet. The second data file is specific to a simulation case and includes descriptions of the flowsheet, various feed streams and the process equipment's operating conditions. In addition to temperature, pressure and percent solids, calculated information for each stream includes weight and volumetric flow rates, chemical compositions, specific gravities and enthalpies of solid, liquid and gas phases. For each process equipment in the flowsheet, APEX prints its operating conditions and detailed information about the streams that enter and leave the unit. Models of several general unit operations are preprogrammed in APEX. Also, the modular design of APEX permits quick and easy additions of simulation models which are specific to new and/or unique process operations. To study process stability and optimization, APEX permits several cases of a flow-sheet to be run together. Three simulations of the Moa Bay Nickel process have been excluded to illustrate the ease and flexibility of using the APEX system.

Jan 1, 1980

By YU. F. Vasyuchkov, K. Vasioutchkov, B. M. Vorobjev

Introduction It is now believed that, even with the environmental protection measures now being taken, the further application of traditional coal-mining and electric power-generation technologies will inevitably cause further irreversible damage to the global ecosystem. Further improvements in conventional coal-mining technologies, both surface and underground, are expected to have only limited impacts on the economical, ecological and social aspects of coal mining. In countries with a developed coal industry, coal reserves with favorable conditions at shallow depths are rapidly being depleted. Therefore, in the future, more coal will be mined from deeper levels, resulting in higher operational costs and lower labor productivity. The solution to this problem is to be found in developing, promoting and implementing unconventional coal-mining and advanced clean-coal technologies. This paper presents an unconventional concept that has been suggested by the authors. The basic goal is to achieve coal-methane energy resource conservation and to remove barriers to energy efficiency through the adoption of integrated, ecologically clean, innovative technology. The following principles form the foundation of this concept: Energy resource conservation: This principle concerns the exploitation of actual and potential coal-methane reserves in the most effective way with the lowest possible losses and with the application of the most energy-efficient electric power-generation technology. Energy conversion: Energy conversion means the conversion of solid coal to synthetic fuel gas (in situ or in-cycle), the conversion of methane bounded within the coal matrix to free-flowing drained meth¬ane, the conversion of solid coal in situ to a coal/water mixture (slurry), and the conversion of these gas fuels into electric power. Technological and managerial integration: This prin¬ciple means an integration of coal-gas methane min¬ing operations and electric power generation into one commercial mine-to-product enterprise with electric power as the final product. Thus, coalbed methane drainage and coal gasification (both in situ and in-cycle) integrated with a combined cycle of electric power generation constitutes a highly integrated coal-gas methane energy-generation system. The system can be materialized in the form of a local integrated coal-gas electric power complex (LICGEPC). General features of the new concept The coal-gas-methane electricity concept is actually a synthesis of the following four technological components: Coalbed methane drainage. This technique and its utilization attained recognition after commercial operations were proven successful in the San Juan and Black Worriers coalfields in the United States. Worldwide, extensive field experiments and research-and-development activities are being carried out in the area of coalbed methane exploitation and utilization. Recently, coalbed methane drainage for power generation has been undergoing intensive research and development. At the Harworth Colliery in the United Kingdom, a combinedcycle power plant has been built that uses coalbed methane. The plant has an installed capacity of 15 MW Also, Germany, Australia, the CIS and China have conducted various experiments and industrial tests on the use of coalbed methane power generation. Underground coal gasification. Another unconventional technological approach is underground coal gasification (UCG). A number of semi-commercial, demonstration and pilot projects have been undertaken in Russia, the Ukraine, Uzbekistan, the United States, the United Kingdom, Italy and Belgium to demonstrate the technical and economical viability of coal gasification in situ. In Uzbekistan, the Angren coal-gasification station has been in full-scale commercial operation for two decades. The operation supplies a power plant with synthetic coal gas. Under sponsorship of the US Department of Energy's Morgantown Energy Technology Center, large-scale laboratory tests simulating coal gasification in situ were successfully completed by the

Jan 1, 1999

By G. Pierson

Explanations for commodity price levels (or movements) commonly focus on the fundamentals of supply and demand otherwise they are simply assigned to speculative activity. Comparisons of metal-price histories to monetary and other economic data support the argument that the supply of and demand for money are no less important in the determination of price than are the supply and demand of the commodity itself. That these relationships should exist is evident in the price identity and they are consistent with monetary theory. The patterns developed have limited usefulness as predictors, but their recognition is essential for the construction of price scenarios for planning purposes.

Jan 1, 1998

By Kalliat T. Valsaraj, Louis J. Thibodeaux

A mathematical model is described for the transfer of hydrophobic compounds from aqueous to an immiscible organic phase using fine bubble aeration; the process otherwise known as "solvent sublation" an adsorptive bubble separation process. The limitations of the model are explored by simulating experimental results both for a batch scale process and a continuous process. The qualitative predictions of the model with respect to the influence of the organic layer (mineral oil) are tested by performing experiments using chloroform and 2,3,6-trichloroanisole as hydrophobic compounds in the aqueous phase. The continuous process is seen to be limited by the requirements of fine bubble generation and the ratio of influent feed rate to air flow rate.

Jan 1, 1989

By G. Pierson

Explanations for commodity price levels (or movements) commonly focus on the fundamentals of supply and demand, otherwise they are simply assigned to speculative activity. Comparisons of metal-price histories to monetary and other economic data support the argument that the supply of and demand for money are no less important in the determination of price than are the supply and demand of the commodity itself. That these relationships should exist is evident in the price identity and they are consistent with monetary theory. The patterns developed have limited usefulness as predictors, but their recognition is essential for the construction of price scenarios for planning purposes.

Jan 1, 1997

By B Faulkner, M. Weinecke

In 1997, Sveciala began a program to develop a process to convert waste tires into valuable commodities. A review of numerous approaches revealed shortcomings that were process related or mechanical related, while some of the approaches emphasized he production of low-value products. A market study revealed that a process that could produce a good grade of carbon black would be economically feasible. This paper discusses the laboratory and pilot-plant development and commercial plant design of such a process.

Jan 1, 2002