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By C. W. Schultz

Introduction The Mineral Resources Institute, The University of Alabama, has for the past three years been engaged in a program to develop a beneficiation system for eastern (Devonian) oil shales. One objective of that program was to evaluate advanced technologies for effecting a kerogen-mineral matter separation. Column flotation was among the advanced technologies selected for evaluation. Early in the program it was shown that column flotation was superior to conventional (mechanical) flotation and to the other advanced technologies being evaluated. The investigation then proceeded toward the further objective of defining the optimum operating conditions for column flotation. One observation made in the course of optimization testing was that introducing the feed into the froth (above the pulp-froth interface) resulted in an improved combination of concentrate grade and kerogen recovery. This observation was reported in a previous paper (Schultz and Bates, 1989). Because the practice of maintaining the pulp froth interface below the feed point is contrary to "conventional" practice, it was decided to subject the observation to a systematic series of tests. This paper describes a recent series of tests and the results that were obtained.

Jan 1, 1991

By Hiroshi Himura, Shoichi Tsushima, Hiromi Goshima

This paper reports the construction of an environmentally-friendly tunnel in sedimentary soft rock near a residential area. The main tunnel, which will be used as the Onmawashi-Koen (Park) Regulating Reservoir, is a large-scale tunnel with a cross sectional area of 254.0 m2 and a lengthof 577.3 m, excavated using such support as shotcrete, rockbolts and steel H-sections. Since the large main tunnel is excavated in sedimentary soft rock, it is necessary to keep the stability of the tunnel face and the crown and to prevent surface settlement. A top heading with a length of 50 m is therefore driven as a pilot tunnel to observe the ground behavior during excavation, and to obtain information on the geological conditions based on which type of support structure is determined with consideration given to the results of field measurements and numerical analyses.

Jan 1, 2001

By Frank T. Wheby, Edward M. Cikanek

A computer performs all logic and computations customarily done by hand in preparation of engineers' estimates or contractors' bids on tunnel-shaft systems. The program described is based on construction methods, work forces and equipment selections corresponding to the current state-of-the-art of rock, soft ground and cut-and-cover tunneling. The program contains logic to permit estimates of cost of complicated tunnel-shaft systems; it is not necessary to input quantities, as the program calculates those from the tunnel design that is internally generated. In any estimate, the program bases its cost computation on user-input requirements and site conditions, such as tunnel shape and size, shaft depth, ground characteristics, construction methods, and other factors. To provide great flexibility, the user of the program is provided with options for accepting designs built into the program or overriding these designs by his own inputs. An illustrative example is presented.

Jan 1, 1974

By Antonio Peralta

Mining activity in Mexico began in the 16th century when the Spanish realized the mining potential of the new territory. Since that time, mining has evolved into a strong and vital industry for the country. Good professionals in the mining-related fields are fundamental to the growth and improvement of this industry. Since the end of the 18th century, formal education in mining has been available at the University of Guanajuato, in Guanajuato, Mexico. This school created one of the first schools of mines on the North American continent in 1828. In recent times, some other programs have been created at other universities. Universities offering mining related programs Listed here are the seven universities in Mexico that offer mining related degrees. They are the University of Guanajuato, UNAM, the University of Zacatecas, the University of Chihuahua, the University of Sonora, the University of Coahuila and the University of San Luis Potosi. The University of Guanajuato is the only Mexican university that offers graduate studies at the master's level. No PhD programs in mining engineering are offered at any Mexican university. Programs at each university are of different duration. They are: • University of Guanajuato-Five-and-a-half years, divided into five years of classroom instruction and six months in the working place. • University of Zacatecas - Five years of classroom instruction.

Jan 1, 1994

By Ross W. Smith, Xiapeng Zheng, Peggy J. Arps

The adhesion (and de-adhesion) of Bacillus subtilis to dolomite was determined under a number of conditions of initial concentration of the organism, agitation, mineral particle size and temperature. Rate equations curves for both adhesion and de-adhesion were constructed, with the rates of de-adhesion being about half that of adhesion. From the temperature data the energy of adhesion was determined to be about 1.02 kcal/mol. Adhesion of dolomite to B. subtilis follows a Langmuir isotherm. Equilibrium constants, adhesion capacity and Gibbs free energy of adhesion of B. subtilis to dolomite (at pH 6.6) were determined. These values were compared to similar data for adhesion of B. subtilis to apatite and dolomite.

Jan 1, 2002

By G. Roy, C. B. Pettersson, S. Nandagiri, D. J. Ivor-Smith

The Coastal Water Authority's 2,740mm/2,590mm (108 in./102 in.) pipeline, known as the Northwest Lateral Project, will transport raw water from an existing pipeline over 14.3 km (8.9 miles) to the City of Houston's East Water Purification Plant. The new pipeline crosses under Houston Ship Channel and Greens Bayou in tunnels at approximately 30.5m (100 feet) and 25.9m (85 feet) depths, which present unique experiences in tunneling under open bodies of water in the Gulf Coast's soft ground conditions. An earth pressure balance TBM is being used for the deep tunnel sections where the ground demonstrates high overload factors and variable conditions ranging from clays to silty sands. This paper discusses the design approach for the tunnels and shafts, ground conditions, constructability, and selection of the primary lining system.

Jan 1, 1989

By P. Tsakiris

The increasing social interest for the environmental issues, forces the authorities to enact more rigorous regulations. The mining industry is one of the sectors that concentrate vigorous remonstrance. It is an absolutely justified reaction, as a result of the numerous contaminated and polluted sites that have been inherited by previous operations and they remain unremedied. The lack of a consolidated global legislation, transfers the burden of decisions to the national level. This paper consists of two parts. At the first part, it discusses the critical role of the state to form an effective environmental policy, feasible for the context of the national economy. Afterwards it analyses two of the main points, which must be considered by the regulator for the excavation activity, the abandoned sites and the duration of the mining investment. The aims are to defuse, in the short-term, the public pressure, protecting the economic growth and, at the same time, to form a basic structure for the development of the corporate social responsibility. The second part presents an alternative financial instrument for the Greek regulatory framework, conformed to the characteristics of the Greek Economy, and analyses the expected benefits both for the business and the social welfare.

Jan 1, 2002

By Joseph Cervik

Methane drainage methods can be broadly classified as surface or underground. Surface methods make use of vertical and slant holes. The underground method discussed in the present paper involves horizontal drilling from shaft bottoms and from locations along the periphery of mines. Every foot of hole drilled in coal from under- ground locations is productive and gas flows increase as hole length increases. Therefore, underground techniques have a great potential for producing large-volume flows of methane. Pumps to dewater the horizontal holes are not necessary because gas pressure forces the water out of the hole. Methane can be recovered through the use of a simple and inexpensive gas-water separator. Hydraulic fracturing, which has been used successfully to stimulate gas flows from vertical holes, has not proved practical in the case of horizontal holes.

Jan 1, 1980

By Andrew H. Stearn, Robert O. Agbede, Edward F. Divers

The ability to compete profitably in a competitive, demanding and specialized market, requires all components of productivity to be optimized toward the same manufacturing goal. This ever present requisite is seldom more apparent than with the quality control (PC) considerations that confront the super-refined metallurgical production necessary for today's exacting technical applications. In a work-place that already exceeds all environmental standards for cleanliness, this paper describes the development of specific environmental mechanisms and controls implemented at a titanium processing facility to impact both the minimal air-borne particulate contaminants and excessive process heat generation which are believed to degrade product purity. Based on the analysis of a carefully structured and instrumented field survey, two alternative solutions were proposed to modify the present facility utilizing a forced air (blowing) system. The first scenario requires ambient air to be drawn from a louvered rooftop installation and ducted to specific zones within the plant with appropriate weighted louvers and wall and roof exhausters designed into the system for air control. The second scenario incorporates a properly sized baghouse to be used in conjunction with the first system.

Jan 1, 1991

By R. F. Holub, P. J. Dallimore

Basic to solving the problem of the role of radon transport on radon concentrations in mines is to establish whether it occurs primarily as diffusion and forced flow through porous rock or through fissures in the rock. The laboratory experiments performed involved measurements of diffusion and emanation coefficients, porosity and permeability of representative rock samples. Significant differences have been found when comparing the results of the laboratory permeability determinations to those of the mine determinations. Considerations of underlying principles, however, suggest that the diffusion and emanation coefficients are the same in laboratory and mine. It was also found that moisture content plays a dominant role in radon transport through rock. Using these concepts and findings, some conclusions about the radon concentrations in mines have been drawn.

Jan 1, 1981

By A. Pavlides

The purpose of this study is to compare estimation methods for lignite reserves at the Amyndeo mine and to provide a map of the estimated thickness of the coal seams. The reserves are first estimated with the method of Voronoi diagrams, using a group of mirror points to close the polygons around the boundaries of the mine. The second estimation method is based on Ordinary Kriging using the Spartan variogram model. Finally, the reserves are estimated by the mean lignite thickness value of the drill-hole data Two data sets are investigated. The first one corresponds to an exhausted part of the mine. The derived reserves estimates are compared with the actual data obtained by the Public Power Corporation (PPC) to validate the analysis. The second data set extends over the entire mine, and it is used to derive an approximate estimate of the total lignite reserves. A geostatistical analysis of the total layer thickness is performed. An interpolated kriging map of the total thickness variation is produced accompanied by a map of the kriging uncertainty.

Jan 1, 2008

By G. A. Achilleos

The insufficiency of Boolean Logic and ?hard? decision making to represent and manage spatial data in set with their spatial errors comprises a remarkable difficulty for widely accepted estimation procedures, in realistic planning of space geometric problems and management through a GIS. Fuzzy logic as well as other theories such as the theory of Probabilities, Bayesian theory etc., contribute substantially towards this direction. Data are accompanied by their accuracy and are managed through the applications and modules of Spatial Analysis, aiming to access a decision with known accuracy and fuzziness. As it concerns the cases of waste sanitary landfill sites designing, which are based on the construction of a bank, the problem shown by this paper, seems to be quite serious. The determination of the theoretical waste disposals body in the landfill is based on an uncertain Digital Elevation Model (DEM). As this model is a result of a procedure enclosing errors and inaccuracies, it is for certain a non - error free model. Thus, the geometric computation of the excavation quantities and the waste disposals solid body volume, misquotes the expected standard theoretical computation and imports the need to decide and set a risk level for the project.

Jan 1, 2005

By Jess H. Albino, Girish Roy, James M. Monsees

Construction of the North Hollywood line of the Los Angeles Metro System required crossing the Hollywood Fault as the twin transit tunnels extend into the San Fernando Valley. The Hollywood Fault is considered active and represents the largest active fault that the North Hollywood Redline extension will cross. The feature is a thrust fault with the north plate overriding the southern plate and creating the Santa Monica Mountains in the process. South of the fault lies the alluvial valley and Hollywood. North of the fault are the Santa Monica Mountains which rise locally to more than 1200 feet. The average overburden at the seismic section is about 300feet and is overlain by Runyon Canyon Park, a municipal park with environmentally sensitive areas. The actual fault plane was anticipated to lie within the southernmost120 feet of the 600 to 700-foot-wide fault zone. The special seismic section constructed for the tunnels consisted of an enlarged cross-section with special lining, drainage and finish features that will facilitate the restoration of metro service in case of a major event occurring on the Hollywood Fault. The discussion will address the geology, the procedure used to define the design event and predicted displacements, the unique design features as well as the construction methods used and the instrumentation and the results obtained.

Jan 1, 1999

By Robert A. Robinson, Steven R. Thompson, Harvey W. Parker

The Mt. Baker Ridge Tunnel, under construction in Seattle, will be the world's largest-diameter soil tunnel with an inside diameter of 19.2 m (63 ft) and an effective outside diameter of about 24.4 m (80 ft). The five-lane highway tunnel will be constructed using a "stacked-drift" scheme in which an articulated or "flexible" tunnel lining consisting of 24 concrete-filled drifts is constructed to form a horizontal compression ring followed by removal of the soil core. Geotechnical factors, including variable strength hard fissured soils, high horizontal stresses, potentially unstable sands, and prior slope instabilities, significantly influenced the innovative design and construction approach.

Jan 1, 1983

By D. J. Shields

The goal of public policies is to connect desired ends with practical means toward their achievement. How the desired ends are determined, and whose goals and objectives they incorporate, depends upon the culture and political system of the country in question. With few exceptions, policies change over time to reflect changed perspectives and understanding of the world around us. This is true regardless of the policy area in question. Thus, how societies view and manage their mineral resources has evolved in response to public attitudes, societal needs, economic circumstance, cultural perspectives, political orientations, technological advancements, and geological knowledge. In this paper we examine how the scope of concern has changed for mineral policy. We then review the overarching issues that have in recent years been considered essential components of mineral policies. We point out how neoclassical microeconomics has influenced recent policy design. We then use a market flow diagram to illustrate how policies can be focused at specific market issues. We next discuss mineral resources in the context of sustainable development. We identify issues that become relevant when the frame of reference is enlarged beyond ensuring supply and capturing economic rent. We show that policy based solely on neoclassical economics may not be able to effectively incorporate these issues.

Jan 1, 2007

By E. Robert Kiehl

In the early days of the United States, gypsum was most commonly used for the manufacture of plasters with energy being used for quarrying, grinding, and calcining of gypsum rock. With the dramatic switch to gypsum-drywall construction after World War II, the energy usage per ton of rock processed increased more than threefold, and with the rapid growth of the construction industry, the total energy consumption in gypsum-board production alone increased eightfold during the period from 1940 to 1973. The gypsum industry was one of the first to recognize the need for energy conservation and has voluntarily reported its progress to the Federal Energy Administration for the past several years. Efficiencies in the use of energy have resulted in decreasing the unit consumption an estimated 10 percent during the past six years. Improved combustion efficiencies, optimum operating conditions, more liberal use of insulation, and heat recovery will all contribute to the gypsum industry's goal of using less energy. Gypsum products today are vital to over 85 percent of new housing construction in the United States.

Jan 1, 1978

By Maurice Deul

Certain health and safety hazards occur entirely unexpectedly in some subterranean excavations. Although ground support is not the subject of this paper, ground failure can result in large and often uncontrolled flow of fluids into an excavation. Even when there is no ground failure, the disturbance of nature's equilibrium between rock or unconsolidated alluvium or rubble and the contained fluids poses severe problems to a well planned operation. Optimum conditions for safe operation cannot be the sole criterion for site selection. Some mineral deposits form in zones of structural weakness, others form where hydrothermal alteration substantially weakens the enclosing rock, and tabular deposits such as coal and evaporites inevitably undermine large areas. Excavation to acquire mineral values cannot be relocated. The same is often true for tunnels driven to connect distant points by the most direct route. Rivers and mountains cannot he avoided, and the cost of lengthening a tunnel--by even a fraction of a percent--must be strongly justified. No responsible engineer will knowingly select a dangerous route for excavation, but to what extent do engineers attempt to assess the health and safety hazards that may be reasonably expected? How, specifically, can methane explosions, water and sand flooding, dangerous dusts, toxic gases, thermal shock and radar poisoning be eliminated or minimized through systematic advance planning?

Jan 1, 1974

By B. C. Cornilsen, X. Shan, D. H. Carlson, J. H. Johnson

Airborne respirable Diesel Particulate (DP) presents an additional health hazard in that it has been shown to be mutagenic. This problem is of increasing concern as more coal mines introduce diesel vehicles. If the DP present in coal mine air is to be controlled it must first be measured. This paper describes development of the laser Raman spectroscopic measurement of the amount of DP in DP/coal mixtures collected on filters in the laboratory and in coal mines. The Raman technique provides a chemical measure of the carbonaceous material in each component, and is not dependent upon particle size. When this work was begun there were no known analytical methods for this measurement. Side-by-side in-mine comparisons of the results obtained from Raman, neutron activation analysis, and size selective analyses (MOUDI and personal samplers) are presented. The neutron activation and size selective analyses were obtained by the USBM Twin Cities Research Center and University of Minnesota. Good agreement has been found among these three methods.

Jan 1, 1991

By George L. Baloo, Dave Kwiatkowski, Jose G. Cañlzales

Capital project funding for a medium to large materials handling project often includes a budget for procurement of supplier-recommended spare parts, and it is the Project Team's responsibility to select these parts. With today's economic climate, limited budget, and other factors, the spare parts selection process is a difficult and arduous effort. This decision carries with it a risk to plant operations and in some cases the commodities producers. Too often the decision-making process is not documented, and the reasons for eliminating and reducing quantities are based on "best guess " Recently on the Solids Handling Phase 2 Project in Jose, Venezuela, the Project Team took a unique approach to this problem. This paper discusses the analytical approach taken by the Project Team, the database system that was developed to manage this problem, lessons learned, and their applicability to pre- project planning and preliminary design.

Jan 1, 2004

By Gemei Yang, Yihui Zhao

In caved goaf, the friction loss of fluid head is: [h = (R'+ R/Q/ )] Q (for one-dimensional transition flow). The R' and R, which are the functions of two dimensional spaces, are calculated through an empirical formula. Then, the bulking factor and permeability are determined. It is supposed that the airflow in porous media are similar to those in tiny tubes crossing each other. Therefore, the network calculation technique can be used to tackle the field transition flow problem. A lot of case studies showed that the emission of methane in mines mainly depends on the air velocity and has little relation to air pressure. Summing up our experience and experiments, we provide an empirical formula to calculate the gas emission rate per unit area. By means of mass conservation and network calculation, the methane content distribution in steady-state is worked out. Then the dynamic change in airflows and gas content can be analyzed by the characteristic-difference method.

Jan 1, 1987