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By Reinhard Gnilsen

Ground pillar control in soil and weak rock often represents a critical and sometimes a determining factor for mined underground civil structures. A concept is desirable that minimizes the restrictions possibly imposed by pillar control requirements on geometrical tunnel characteristics and on the mining operation itself. Conventional concepts are discussed and an alternative concept is introduced. This concept reduces pillar control requirements to ground control measures required with "regular" tunnels. The conventional model of pillar mechanics with potential yielding of a ground body in more than one direction, is then avoided. Due to the complexity of pillar mechanics, the level of engineered design furnished to the contractor is crucial to optimizing ground pillar control. Conventional versus alternative contractual arrangements for pillar control are described and their important role is illustrated. The concept introduced relates to principles inherent to the New Austrian Tunneling Method (NATM). However, tunnel projects using other mining concepts can employ alternative ground pillar control principles as well, if certain criteria are observed. Case histories in the United States and abroad are presented and the impacts from different concepts of ground pillar control are illustrated. The paper concludes by analyzing concept characteristics that can infer monetary impacts on both the owner and the contractor.

Jan 1, 1987

By G. R. Tostengard

Gold plant performance during the start-up period, which extends until capacity production is sustained, has a major impact on the internal rate of return and the net present value of gold projects regardless of mining and processing configurations. The start-up period experiences substandard production, extra expenses, and sometimes reduced recovery. This results in lost profits, a portion of which are recouped at the end of the life of the mine. Poor start-up performance can put projects into financial jeopardy. The gold mining industry regularly experiences start-ups ranging from good to poor. Problem areas, which affect start-up performance, include shortcomings in ore reserve sampling and testing, equipment design and installation, untrained plant operators, inability to cope with problems which arise, and organization of the maintenance program. An investment, equal to 0.5% to 1.0% of plant capital cost, in programs to prepare for start-up, in advance, is recommended. Investment in such a program will make a good start-up possible. Without it the best result which can normally be expected is a fair start-up. Developers of new gold mines are urged to compare the cost of this investment with the anticipated increase in project net present value. Funds for this investment should be included in feasibility studies.

Jan 1, 1988

By Y. C. Kim, M Nataraja, J. T. Buckley, D. H. Tiktinsk

The Nuclear Waste Policy Act of 1982 (NWPA) assigns the U.S. Department of Energy (DOE) the responsibi1it.y of locating, constructing. operating, closing and decommissioning a nuclear waste repository. Prior to submittal of a licensee application to the U. S. Nuclear Regulatory Commission, the DOE is required by 10 CFR part 60 to conduct a program of site characterization for the site to be described in such application. Site characterization includes an exploration and research program in the field and laboratory to determine the geologic conditions and ranges of those parameters which are necessary for determining the suitabi1it.y of the site as a geologic repository. The information thus collected should be able to establish with reasonable assurance that the public and environment will be adequately protected from the hazards associated with a repository at the site. This paper demonstrates by example a geostatistical approach which, on the basis of the existing limited data base, can be used to evaluate (1) whether existing information on a certain parameter is adequate to be considered representative. (2) if additional information is required, where should the additional sampling or testing be performed, and (3) whether the new1.y acquired data along with the existing information constitute representative data.

Jan 1, 1986

By Ian J. Duckworth, Pierre F. X. Mousset-Jones

A detailed heat flow project was conducted at the Homestake Mine in Lead, South Dakota. This paper presents results obtained from a stope sensor system installed in the mine. The design and installation of the system are described in detail in a previous paper (Duckworth et al., 1992). The major project objective was the construction of a comprehensive heat flow data base to allow the design and testing of a new climate prediction model applicable to irregularly shaped underground excavations in non-homogeneous surrounding rock types. A mechanized cut-and-fill (MCF) stope contributes a substantial overall heat source in a mine, and the effect of this source on the working environment must be considered when planning future ventilation and refrigeration requirements. The relative magnitudes of the component heat sources encountered with the MCF mining technique are presented, having been computed from actual stope beat flow data collected over a one-month study period. The percentage of the overall heat load that is removed from the scope for each component heat sink is evaluated, and the overall energy balance is analyzed. A one-month study length was considered a sufficient period of time to allow stope monitoring for a complete range of mining conditions.

Jan 1, 1993

By Michel Claisse, R. P. Goel, André J. Rancourt, Kent Murphy

The Malana Hydroelectric Project is a private development located in HimachalPradesh State, India that was commissioned in June 2001. The plant was built and is owned by the Malana Power Company, a subsidiary of the Bhilwara Group of New Delhi. With a total head of 400 m and nominal capacity of 86 MW, the plant is capable of generating 360 GWh annually. The 3,1 km long, 4,0 m diameter power tunnel was designed to be excavated by conventional drill and blast methods. Contrary to traditional practice in India for pressure tunnels of providing a concrete lining, the Malana tunnel was finished mainly with shotcrete. In this way, the tunnel was completed in a period of18 months, a record for recent projects in the Himalayas, and at a cost substantially below that of conventionally lined tunnels. An interesting aspect of the project was the design of the steel tunnel liner linking the power tunnel to the penstock. The length of the liner was fixed finally on the basis of in-situ testing using both hydraulic jacking and doorstopper tests to evaluate the ability of the rock to withstand the internal pressure of4,0 MPa that exist near the downstream end of the tunnel.

Jan 1, 2003

By K. T. Dreher, J. A. Brierley, C. L. Brierley

Water from underground uranium mines located in the Ambrosia Lake district near Grants, New Mexico, U.S.A., is treated to reduce levels of uranium, selenium, radium and molybdenum. The treatment system consists of a series of ponds and an ion exchange plant. Bacterial and algal populations present in the pond system are considered agents which actively assist in removal of the pollutants present in the water. Pondbottom sediments maintain a reducing zone and a large population of sulfate-reducing bacteria of the genera [Desulfovibrio] and [Desulfotomaculum]. Uranium, molybdenum, and selenium accumulate in the pond sediment. Stimulation of the microbial sulfate-reducing activity resulted in a decrease of soluble concentrations of these elements in laboratory systems. Predominant components of the treatment ponds’ algal flora are the filamentous [Spirogyra] and benthic [Chara]. Laboratory study indicates that [Spirogyra] is more active than [Chara] in removal of uranium and molybdenum from solution. However field-collected algal samples of both of the genera contain uranium and molybdenum. Laboratory studies indicate that death and decay of the algae in association with pond sediment does not result in return of cellbound uranium and molybdenum to the water. The algae appear to act as bio-filters for accumulation of particulate pollutants and agents for adsorption and/or absorption of soluble pollutants.

Jan 1, 1980

By Randal J. Barnes

There are many methods available for the estimation of geologic parameters (Popoff, 1966; Barnes, 1980). In the last decade a new and relatively sophisticated technique using statistical theory has emerged: geostatistical kriging (David, 1977; Journal and Huijbregts, 1978; Rendu, 1978). An interesting property of geostatistical estimation is that when a geologic parameter is estimated for a given volume, not only is the estimate generated but an associated measure of certainty is produced as well. This statistical measure of estimation confidence is called the estimation variance. While the concept of an estimation variance is universally considered to be a good idea, mining engineers and geologists do not currently have the tools to incorporate it into their planning and quantitative analysis. This paper attempts to develop and present some of the necessary tools required to incorporate estimation uncertainty into mine planning. Geologic uncertainty is portrayed as an economic business risk. This risk is objectively characterized, and-the associated cost is quantified. Geologic delineation sampling is viewed in this light as an economic commodity with an associated cost and value. A coal mine planning example is used as a focus in this presentation. The data used is real, though it has been modified to maintain data security and project anonymity.

Jan 1, 1986

By Victor S. Sazhin, Alexander Kostenko

The hydrochemical method, which is based on the separation of aluminium oxide and silicon oxide by the hydrothermal decomposition of aluminosilicates by alkaline solutions in the presence of calcium oxide, can be effectively used for the complex processing of high-silicon aluminium ores. In this case, the silica is bound to a slightly soluble compound: Na20.2Ca0.2Si02•H20 (under the conditions: [&k]= 9, CaO/SiO2 = 1.05, alkali concentration in the solution: over 300 g/l Na20, T = 240...300 °C). If alkaline solutions of 100...150 g/l Na20 concentration are used, Ca0•SiO2•H20 or 2Ca0•Si02.0.5H20 compounds, depending on calcium oxide dosage, are formed at 280...320 °C. New methods for the crystallization of Na20.Al203.2.5H2O from concentrated alkaline solutions rand low-concentration solutions are proposed to isolate aluminium from solutions. The hydrochemical method, which involves no sintering process allows one to decrease the expenditure of heat by a factor of two, to reduce the investment and to exclude the pollution of the ambient air by dust-laden gases. The expansion of the raw-material resources base of

Jan 1, 1984

By José Luis Lee Moreno

This paper presents a preliminary phase of a study being conducted by the Department of Geochemistry of the Consejo de Recursos Naturales No Renovables in the vicinity of the Pachuca-Real del Monte Mining District. This district is located in central Mexico, about 100 km northeast of Mexico City. It has been in operation for the past 450 years and has produced about 38 million kg of silver and about 190 thousand kg of gold. At the present it is being worked by the state owned mining company of Real del Monte and Pachuca. The rocks of the area consist mainly of Tertiary volcanics, ranging in age from early Oligocene to late Pliocene. Ore bodies are recognized as epithermal, vein type fracture fillings. The main ore minerals are argentite and acanthite normally accompanied by base metal sulphides, Gold is present in small amounts as native gold and in other minerals. Orientation geochemical studies performed on soil and rocks over known veins in the district, showed zinc to be the best indicator. Lead and silver anomalies are restricted to the immediate vicinity of the veins, mercury shows the mineralized structures only when the "C" horizon is sampled, while antimony gave erratic values. The El Chico area is about 10 km north of the Pachuca-Real del Monte district and covers approximately 400 sq km. Geological evidence indicated the possibility of an extension of the Pachuca ore bodies in this area. Results obtained from soil and rock samples from El Chico, showed several anomalous area. Detailed investigations proved these anomalies to be related to faults and fractures which in several cases have been found to be mineralized. Drilling is planned with preliminary results expected by late 1974.

Jan 1, 1974

By J. Fox, C. Allen, A. Greth, K. Kocsis

"It is the duty of the mine operator to ensure the mine environment is healthy and safe for the mine workers. For deep and hot underground mines, this requires maintaining adequate working temperatures by means of mitigating the heat load generated by strata, auto-compression, mining equipment, explosives, ground water, and human metabolism. The heat load is best reduced by minimizing the amount of heat transferred to the mine air from these sources and through the use of efficient ventilation with effective cooling systems. The heat emitted by mining equipment and vehicles contribute a significant proportion to the combined heat load of an underground mine. This is especially a problem for diesel equipment due to the fact that besides heat, a large amount of water vapor is produced, which increases the humidity in the production workings. Diesel engines have proven advantageous in recent history due to their high power output and reliability. However, as mines continue to become more mechanized and deeper the climatic problems introduced by elevated heat generation will continue to rise. With that, the issue of heat generated by diesel equipment must be addressed. The economic alternative for diesel engine equipment fleets in underground mines is the electric engine. Technological advances in battery technology, increased mechanical output and improved reliability have made the electric engine significantly more competitive in comparison to diesel engines. Because electric engines do not utilize internal combustion, the heat produced by them is significantly less than of the diesel engines. Battery powered mining equipment likewise eliminate diesel particulate matter (DPM) produced by diesel engines. Utilizing battery electric equipment in underground mines provides many advantages, such as: (a) reduced heat load, (b) healthier and safer environment for the mine workers, and (c) reduced mine operating costs due to lower ventilation requirements. This paper will highlight the health and cost benefits of using battery/electric fleets versus diesel fleets in deep and hot underground mines. The study analyzes simulations produced from thermodynamic ventilation models. Early simulations show significant cost reductions in terms of net present value (NPV) when comparing the air volume requirements for battery/electric equipment versus diesel powered equipment for the same production rate. INTRODUCTION The competitiveness of the world mineral market demands that mine operators continue to increase production and decrease costs as commodity prices fluctuate in often unplanned directions. This has forced underground mines to operate at deeper depths and to become more mechanized to remain competitive. Because of these changes, ventilation challenges have continued to increase as the mines combat an enlarged influx of contaminants such as heat and diesel particulate matter (DPM)."

Jan 1, 2018

The purpose of the 3DOPT Program is to determine, starting from drill hole data, the optimum economic mining limits for an open pit. The economic limits are defined as those which maximize total profit, i. e. total mineral value mined less the total mining and milling costs, subject to the restriction imposed by the pit slopes. To accomplish this, the program employs the following: (1) A three dimensional matrix of equal sized blocks in order to file the engineering data and the cost/value data required to develop the profit figure for each block of ore/waste. (2) A graph algorithm developed specifically for optimizing these profits.1

Jan 1, 1966

By B. R. Arvidson

Rare-earth elements have some unique properties that are used in many common applications, such as TV screens and lighters. In the 1970's, rare-earths began to be used in a new generation of magnetic materials that have very unique characteristics. Not only were these stronger in the sense of attraction force between a magnet and mild steel (high induction, B), the coercivity (He) is extremely high. This property makes the magnetization of the magnet body composed of a rare-earth element alloy very stable, i.e., it cannot easily be demagnetized.

Jan 1, 1998

By I. Yu. Melekestseva

Two types of hydrothermal massive sulfide fields were discovered in the Mid-Atlantic ridge (MAR) in the last twenty years. The first type associates with basalts and includes the TAG, Snakepit, Broken Spur, Lucky Strike and Krasnov hydrothermal fields. The second type is related to ultramafic rocks and represented by the Logatchev, Rainbow and Ashadze hydrothermal fields. In 2007 a new, probably, the largest cluster of hydrothermal massive sulfide field on the MAR (Fig. 1), related both to basaltic and ultramafic rocks, was discovered at 13°31'N of the MAR (Beltenev et al., 2007). [ ]

Jan 1, 2008

By Hongjie Yu, Rakshith Shetty, Claudio Cimiotti, Nick Karlin, Mike Mooney, Vitaly Proshchenko, Matt Kendall

This paper documents an effort to explain cutterhead torque behavior observed during slurry pressure balance TBM tunneling through soft ground on the Los Angeles Clearwater project. AI machine learning and mechanics model-based learning was used to characterize cutterhead torque behavior including the TBM operating and ground parameters that influence cutterhead torque. Also, key parameters were from the slurry circuit data, including fines content, in-situ density, pore water fraction and solids content were included. The paper details what was learned using these new data-driven approaches as well as limitations with AI machine learning.

Jun 23, 2024

By A. D. S. Gillies

The effectiveness of coal mine face ventilation and the ability of air flow to maintain satisfactory methane and respirable dust levels in the working face area has been studied through the use of scale modeling techniques and underground testing procedures. In particular, consideration has been given to examination of the effects of operation of a high air flow machine mounted dust scrubber unit on face air patterns. Results obtained through a cooperative study with the Peabody Coal Company demonstrate that new mining cycles can be considered which increase production efficiency while maintaining satisfactory ventilation conditions.

Jan 1, 1982

By Floyd L. Prestridge

A test of a solvent extraction (SX) pilot plant featuring electrostatic coalescence has been performed by C-E Natco at the United Nuclear uranium mill in Church Rock, New Mexico. Operating in parallel with the United Nuclear SX system, the C-E Natco electrostatic SX pilot plant exhibited comparable extraction efficiency to the United Nuclear system which utilizes conventional mixer-settlers. The C-E Natco pilot, however, operated at much higher liquid loading rates and exhibited less communication between the aqueous phases of the extraction and stripping circuits.

Jan 1, 1983

By Donald P. Schlick

Gentlemen, today I would like to talk to you about metal and nonmetal mine health and safety--past, present and future. Briefly, I will comment on the past because it is important to an understanding of our present activity and our plans for the future. Federal inspection of noncoal mines was not authorized until 1966, when congress passed the federal metal and nonmetal mine health and safety act; public law 89-577, with the passage of this act, the federal inspector, for the first time, had the delegated authority and responsibility to enforce health and safety regulations designed to prevent personal injuries and occupational diseases, the new law also provided for the education and training of our miners; assistance to the operator through the transmission of technical and scientific information and assistance and equally important, the law made provision for state participation in the congressional mandate to prevent injuries and save lives in the mineral industry, Before I tell you about our program and our future plans, I want you to know that I am here to listen as well as to talk! In my view, the only kind of communication that is meaningful is two-way communication. Our nationwide progress in metal and nonmetal mine health and safety during 1972 cannot be measured in reduced fatalities or injuries. The unforeseen tragedy that took pace in Kellogg, Idaho, in may of last year mode that almost a certainty.

Jan 1, 1973

By Adrian Fleming

Adrian Fleming is Executive Vice President of Exploration for Golden Star Resources Ltd., Denver. Adrian is an Australian who graduated in 1973 with an honors degree in geology from Newcastle University, New South Wales. His extensive international experience has spanned exploration, project development, and operations for both large and small companies in Australasia, Southeast Asia, North and South America, and Africa. Adrian has been with the Golden Star group of companies for four years and he is responsible for all exploration activity. ABSTRACT Golden Star acquired the rights to the Omai prospect in 1985 at a time when the country of Guyana was out of favor with the exploration fraternity. Subsequently in the late 1980s and early 1990s, Golden Star acquired exploration properties in Suriname and French Guiana well ahead of its competitors. Golden Star's strategy entailed identifying windows of opportunity and aggressively pursuing them. We also recognized that the Guiana Shield hosted a significant area of highly prospective greenstones which were comparable in metallogenic potential to similar terrains in eastern Canada, western Australia and west Africa. The geological skills Golden Star developed and the exploration techniques employed to explore deeply weathered rocks are described. The paper highlights the key elements of Golden Star's strategy and illustrates how some of the milestones reached by the company led Golden Star to establish an enviable portfolio of gold and diamond properties in the Guiana Shield.

Jan 1, 1998

By Andrzej M. Wala

A prototype expert system for planning and designing an underground coal mine has been developed in a doctoral study at the University of Kentucky. This prototype expert system for underground coal mine planning and designing consists of a number of knowledge bases concerning different elements of design (e.g., ground control, excavation and bulk materials handling, ventilation, etc.). The objective of this paper is to present the development process of the ventilation design knowledge base for this prototype. This expert system prototype is intended for building an instructional expert system for underground coal mine design. Therefore, the undergraduate course on mine design has been used as the basis, for its development. Because of the availability of knowledge and expertise, this research study has been limited to development of a knowledge model for the Appalachian coal mining region.

Jan 1, 1993

By Peter S. Schneidkraut

This paper will discuss the Final Tunnel Linings which were placed in 6700m of a 2.32m inside diameter precast concrete lined interceptor sewer tunnel in Staten Island, New York. Two methods were employed to install the final tunnel linings. One method involved forming and placing a polypropylene fiber reinforced concrete cunnette invert, followed by an arch pour. The second method involved the jacking of reinforced concrete pipe into the tunnel, followed by a low density cellular concrete backfill grout. These two methods will be described and compared.

Jan 1, 1993