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By R. E. Snow

The analysis of ground water inflow and discharge from underground mines has received increased attention in recent years due to environmental issues which must be addressed under current state regulations for coal mining and processing operations. In particular, coal operators must assess the probable hydrologic consequences associated with mining activities, and must plan for mine water handling during operation and following completion of mining. The prediction of ground water inflow rates with future mine development allows preparation for potential operational problem and identification of inflow reduction methods. Similarly, evaluation of mine discharge rates is necessary to address potential long-term acid mine drainage (AND) concerns. As part of mine discharge analyses, methods. to control seepage and AMD can be considered. The objective of this paper is to discuss the practical applications of mine inflow and discharge analysis, describe the typical flow components, outline the procedures necessary to perform the analysis, and illustrate the modeling procedures and potential results of mine inflow and discharge predictions.

Jan 1, 1990

By Brian E. McGee

The Federal Coal Management Program represents the culmination of several years of effort by the Department of the Interior (001) to reformulate the manner in which coal owned by the United States is leased and developed. These efforts began in 1970 with a study by the Bureau of Land Management (BLM), which indicated that unless drastic changes were made in. the federal coal leasing procedures, federal coal lands would be leased almost for the asking while production of coal from those lands had been decreasing. Consequently, informal action was taken in 1971, which resulted in no further leasing being authorized until February, 1973. At that time, a formal moratorium on most coal leasing was established, with exceptions granted only for leases needed to satisfy short-term needs such as maintaining existing mines or supplying reserves for new contracts in the immediate future. This leasing policy embodied a long term objective of developing an entirely new planning system for federal coal leasing, as well as to schedule the preparation of a programmatic impact statement for this new system. As a result of the 1973 moratorium and the ensuing application of short-term criteria, only 10 federal coal leases (covering approximately 30,177 acres) were issued from February, 1973, through January l, 1976.

Jan 1, 1982

By Alexander I. Feldman, Michael S. Kucker, Robert A. Robinson, Harvey W. Parker

An extensive geotechnical monitoring program was used to assess ground and liner behavior, provide input to a Disputes Review Board, and verify design assumptions during construction of the Mt. Baker Ridge Highway Tunnel along I-90 in Seattle, Washington. The stacked-drift tunnel liner was constructed with twenty-four 2.9 m diameter concrete-filled drifts forming a semi-flexible compression ring, followed by excavation of the 19.4 m diameter soil core. Instrumentation data was used for monitoring hillside stability, liner deflections and loads, impacts on adjacent highway tunnels, for back analyzing soil properties, and for helping to limit construction-induced settlements to about 6 cm.

Jan 1, 1987

By A. Yehia

Fluoride activation has been evaluated by Hallimond-tube flotation of collophanite in terms of fluoride concentration, conditioning time, pH, and temperature. The results reveal that efficient oleate flotation of collophanite can be achieved by fluoride activation. Fluoride adsorption by collophanite as a function of fluoride concentration, temperature, pH, and crystal structure suggests that, at low fluoride concentration, a fluoroapatite-type compound may form on the collophanite surface by chemisorption of fluoride ions at calcium sites; at high fluoride concentration, calcium fluoride ap¬pears to form at the collophanite surface invovling a surface-precipitation phenomenon. The formation of CaF2 on the surface of fluoride-treated collophanite is further substantiated by the FTIR spectroscopic measurements, which clearly shows a metathetic exchange with phosphate from the collophanite lattice during surface precipitation process.

Jan 1, 1986

By Girish Roy, Robert Goodfellow, Angel Del Amo, Bingzhi Yang

Designing and constructing tunnels in seismic prone areas present unique challenges to both designers and contractors. The Westside Purple Line Extension Project– Section 3 in Los Angeles requires crossing an active fault that may subject the tunnels to extreme structural demands. In order to ensure that the linings will safely accommodate the fault movement, a revolutionary composite section—steel plate embedded in the intrados of the precast concrete segmental tunnel lining was finally selected. Additionally, continuous expansion steel plates over the circumferential joints will be installed to mitigate the potential opening of the circumferential joints.

Jun 13, 2021

By Fernando Jorge Dick

Artificial sulphides have been produced on the surfaces of heavy metal-oxide, minerals at elevated temperatures (1) and these sulphides gave consistently similar flotation characteristics as the respective natural sulphides. In the case of tin, the only natural tin sulphide known is herzembergite (SnS) which is found only in minor quantities, and its flotation behavior is not known. Balberyszki, Dorenfeld, and Carmi reported (2) tests with artificial tin oxide and pure cassiterite treated with hydrogen sulphide at temperatures above 750oc. They confirmed that the product could be floated in acid pulps. However, iron sulphides derived from pyrite, limonite, and hematite which are generally the major impurities in tin bearing ores could not be separated from tin sulphides under the conditions used by previous investigators. As a practical matter, if complex tin ores or complex low grade tin concentrates are to be treated by this process, it is necessary to be able to separate sulphidized cassiterite from other sulphidized minerals in the feed. The major metallic minerals, by weight, in complex tin ores are the iron minerals--pyrite, hematite, limonite, magnetite and pyrrhotite. These minerals become (or remain) sulphidized during the sulphidization process.

Jan 1, 1978

By Keith G. Wallace, K. M. (Chris) Chmura, Kirk H. McDaniel

The Waste Isolation Pilot Plant (WIPP) performed a feasibility analysis for the purpose of either modifying, supplementing, or replacing its two main mine fans. The WIPP, located near Carlsbad, New Mexico, is a U.S. Department of Energy (DOE) fa¬cility designed to demonstrate the permanent, safe disposal of U.S. defense-generated transuranic waste in a deep bedded salt deposit. Since the centrifugal fans were installed in 1988, multiple op¬erational and performance concerns have been identified. A com¬prehensive engineering study was conducted in 1995 to: 1) Qualify and quantify operational concerns, 2) Evaluate possible alternatives, and 3) Recommend an optimum solution. Multiple system modification and/or replacement scenarios were evaluated with associated cost estimates developed. The study considered replacement with either centrifugal or axial fans. Multiple fan duties are required at the WIPP. Therefore, Variable Frequency Drives and Inlet Vane Controls (IVC) were investigated for centrifugal fans. In-flight adjustable blades were investigated for axial fans. The study indicated that replacing the existing system with two double-width, double-inlet centrifugal fans equipped with IVCs was the best choice. This alternative provided the most desirable combination of: 1) ensuring the required operational readiness, and 2) improving system performance. The WIPP is currently planning to replace the first fan in 1997.

Jan 1, 1997

By Keiichi Fujita, Michio Miyoshi, Hisashi Miyazaki

In the construction of "Hamacho" subway station (Tokyo Metropolitan Rapid Transit), in order to minimize ground surface settlement, the pipe-roof method was employed as an auxiliary measure when removing the portion between two parallel shield tunnels to form one large tunnel for the station. 14 steel pipes (dia.1,219.2mm, length 75m) were driven in horizontally so as to cover tunnels and support heavy and extremely soft covering soil and surface structures. Procedures of temporary supporting, excavation under compressed air, reinforcing, concreting, etc., and some comparisons with conventional methods are described.

Jan 1, 1979

By A. D. Hammond

Vanadium is a transition metal, ductile, silver-gray metal. It is harder than most metals and steels and it has a good resistance to corrosion, it is stable against alkalis, sulfuric and hydrochloric acids. Vanadium is oxidized in air about 660 °C, although an oxide layer forms even at room temperature. The chemistry of vanadium is noteworthy for the accessibility of the four adjacent oxidation states 2-5. In aqueous solution the colors are lilac V2+, green V3+, blue VO2+ and, at high pH, yellow VO42-. Considered to be as abundant as zinc, metallic vanadium is not found in nature, but it is known to exist in about 65 different minerals. Economically significant examples include patronite (VS4), vanadinite (Pb5(VO4)3Cl), associated to the uranium mineral carnotite (K2(UO2)2(VO4)2?3H2O) and in a vanadium mica called, roscoelite K(V3+,Al,Mg)[(Si,Al)4O10](OH)2. Other important vanadium ore oxides are montroseite (V,Fe)O(OH) and corvusite (Na,Ca,K)V8O2.4H2O. Much of the world's vanadium mine production comes from magnetite-hosted deposit and to a lesser extent, in sedimentary-hosted sandstone. Vanadium is also present in bauxite and in fossil fuel deposits such as crude oil, coal, oil shale and tar sands. In crude oil, concentrations up to 1,200 ppm have been reported. A significant vanadium production comes from the processing of petroleum residues, fly ash and recycling spent catalysts. In 2011, metallurgical applications accounted for 93% of the use of vanadium. Here, an alloy called ferrovanadium is utilized to strengthen steel to be used as rebar in the construction industry, in the manufacturing of axles, crankshafts, gears and chassis in the automotive and transportation industries and in the manufacturing of high-speed tools. In the aerospace industry, vanadium is utilized as a titanium alloy in the manufacturing of airframes and jet engines. The reason for the wide use of vanadium as alloy is its high strength-to-weight ratio, the highest of any engineered material on earth. The major non-metallurgical use of vanadium is in the production of catalysts for the chemical industry. The most commercially important compound is vanadium pentoxide (V2O5), which is used as catalyst in the production of sulfuric acid.

Feb 23, 2014

By N. P. Titkov

This paper presents the results of laboratory and pilot plant investigations for the development of efficient methods of beneficiating hematite ores from the Krivoi Rog, Kursk Magnetic Anomoly, Olenogorsk, and other localities. The tests included gravity, magnetic (in a high intensity field), flota¬tion, and magnetizing roasting methods. It was possible to develop efficient beneficiation methods depending on the mineral composition of the ore and degree of dissemination of ore and gangue minerals. The paper shows the relationship between the iron silicate and quartz content of the ore and the technologic indices of the various beneficiation methods. Some of the conclusions based on these investigations and the technical and economic computations related to the cost of one ton of pig iron produced from concentrates obtained by the various beneficiation methods are: 1. If the hematite ore is not disseminated uniformly, it is expedient to use a combined gravity and flotation process. Ore particles up to 50 am. in size are beneficiated by gravity (heavy suspension, jigging, and others) and yield a lump concentrate. The middlings from this process are recrushed and floated; 2. Finely disseminated hematite ores, containing small quantities (less than 5 percent) of iron silicates, are most effectively beneficiated by flotation. Anionic (sulphate soap, tall oil emulsion with various foam depressors) as well as cationic collectors may be used. Depending on the mineral and chemical composition of the ore, it is possible to obtain concentrates containing up to 65 percent iron with an extraction up to 94 percent; 3. Finely disseminated, mixed hematite-magnetite ores may be beneficiated by flotation or a magnetic separation-flotation process; 4. Finely disseminated hematite ores, containing large quantities of iron silicates and earthy hematite ores are most efficiently beneficiated by the magnetizing roasting method. This method will yield concentrates containing up to 68 percent iron with extractions up to 90 percent. Although beneficiation by the magnetizing roasting process is costly, it will nonetheless, when employed on this type of ore, yield the least expensive pig iron.

Jan 1, 1960

By Siddhartha Roy, Hemant Agrawal, Ram Madhab Bhattacharjee, Devi Prasad Mishra

The paper addresses heat stress in underground coal mines, which poses significant threats to miners’ health, safety, and productivity. It involves a comprehensive ventilation survey in three deep and mechanized underground coal mines in India. Using VentSim software, 3D simulation models were developed to predict heat stress conditions and explore the application of auxiliary ventilation and spot coolers to reduce heat stress.

Oct 1, 2023

By William D. Cassity, Batric Pesic

Introduction Gold mining on an industrial scale is becoming increasingly dependent on low-grade refractory sulfide ores that contain large amounts of pyrite (FeS2) and arsenopyrite (FeAsS). Gold is usually present as sub-microscopic particles dispersed evenly throughout the sulfide matrix. Without some form of preoxidation, efficient recovery of this finely disseminated gold through cyanide leaching is hampered because the surface of the sulfide particle becomes passivated and impervious to penetration of the cyanide. Traditional methods for recovery of refractory gold from arsenopyrite ores include roasting and autoclave leaching. A modem alternative method is to preoxidize the mineral using the bacterium Thiobacillus ferrooxidans prior to attempting to re- cover the gold through cyanidation. The bioleaching of arsenopyrite ores presents a problem in the mobilization of large quantities of arsenic, present both in the +5 and +3 ionic states. Dissolved arsenic species pose a dual problem: they are -1 to the bioleaching process itself through inhibition of bacterial activity, and they also pose an environmental threat. The arsenate anion (AsO2) has been shown to be more toxic to living organisms, including Thiobacillus ferrooxidans, than the arsenate anion (AsO43) (Collinet and Morin, 1989). There is some disagreement as to the fate of arsenite in bioleaching solution. Mandl, Matulova, and Docekalova (1992) reported that dissolved arsenite concentration was constant during a long-term bioleaching study of chalcopyrite using Thiobacillus ferrooxidans. Torma and Oolman (1992) report that Thiobacillus ferrooxidans has been found capable of oxidizing As3+ to As5+. The solid products of arsenopyrite/pyrite bioleaching include jarosite (MFe3(SO4)2(OH)6 where M can be K+, Na+, NH4+ or H3O+), scorodite (FeAsO4.2H2O), ferric hydroxides, and ferric hydroxysufites (Carlson et. al., 1992; Van Breemen, 1982; Lazaroff et. al., 1982). The particular species formed is a function mainly of pH. Little study has been performed on the effect of solid products on bioleaching. Pesic and Kim (1993) showed that Thiobacillus ferrooridans cells served as a nucleation sites for jarosite particles, which grew rapidly and eventually killed the cell. Most bioleaching studies are performed at low pH&apos;s (<2.0) under uncontrolled conditions. By studying bioleaching of arsenopyrite under controlled pH conditions and at higher pH&apos;s (2.0 to 3.0), the distribution of iron and arsenic between the solid and liquid phases can be controlled, and their effects studied. The objective is to develop a bioleaching process that operates at high efficiency while keeping amounts of dissolved heavy metals low. Pesic, Stohok, and Torma (1993) demonstrated the usefulness of this approach in the leaching of cobaltite (CoAsS) concentrates. Materials and Methods The focus of this study was the bioleaching of arsenopyrite ore by Thiobacillus ferrooxidans. The parameters studied included the effects of pH, and the effects of arsenate (AsO43 and arsenite (AsO2). pH studies included pH set initially but not controlled, and pH controlled continuously with NaOH or LiOH. Bioleaching results from two strains of Thiobacillus ferrooxidans with different adaptation histories were compared. Bioleaching experiments were conducted in 150 ml stirred glass reactors using a strain of Thiobacillus ferrooxidans adapted to arsenopyrite ore, supplied by the U.S. Bureau of Mines. These bioreactors were innoculated with stock cells grown on arsenopyrite ore for 14-16 days. Typical elemental breakdown for this ore was: As, 9.90%; Fe, 18.60%, Stot, 9.26%; Suifide, 7.50%; SiO2, 25.90%. Mineralogically, the ore contained both arsenopyrite and pyrite. Bioleaching efficiency was measured by withdrawing bioleach solution samples at selected intervals, filtering, and measuring the amount of dissolved cobalt, iron, and arsenic by atomic absorption spectroscopy. Because the precipitation of iron and arsenic at higher pH&apos;s would lead to unreliable results, a 100 mg tracer of cobaltite concentrate from the Blackbird mine in southern Idaho was added to solution. Dissolution of the cobaltite tracer was used to indicate bioleaching of the bulk arsenopyrite ore. Cobalt has been shown to be stable in solution even when iron and arsenic were precipitated (Pesic, Storhok, and Tonna, 1993). The pa-

Jan 1, 1995

By K. N. Han, Q. Xu

The adsorption behavior of gold in ammoniacal solutions on activated carbon was studied. The gold adsorption capacity of the activated carbon and the recovery efficiency were examined. The parameters affecting the adsorption of gold on the activated carbon included temperature, agitation speed, the concentration of cation and anion and the concentration of ammonia. It was found that the maximum gold adsorption was about 10 kg/t of carbon. The recovery of gold by the adsorption, from ammoniacal solutions was found to be dependent upon the initial gold concentration. Under experimental conditions, a gold recovery of 98% was obtained after 120 hrs of adsorption. It was also found that the initial adsorption rate was relatively fast, when compared to the entire adsorption period. The apparent activation energy for the adsorption was determined to be 15.8 kJ/mol. It was believed that the kinetics of gold adsorption on the activated carbon was controlled by pore diffusion.

Jan 1, 1997

By A. Podlesny, E. N. Rubinstein, J. J. Sammarco, B. Demich

Roof bolting typically follows the extraction of a commodity to help keep the roof from collapsing. During 2004 to 2013, roof bolter operators had the highest number of machinery-related injuries, accounting for 64.7 percent, at underground coal mines. This paper analyzes U.S. roof bolter fatal and nonfatal lost-time injury data at underground work locations for all commodities from 2004 through 2013 and determines risk indices for six roof bolting tasks. For fatal and nonfatal incidences combined, the roof bolting tasks in order of the highest to lowest risk index were bolting, handling of materials, setting the temporary roof support (TRS), drilling, tramming, and traversing. For fatalities, the roof bolting tasks in order of the highest to lowest risk index were handling of materials, setting the TRS, bolting, drilling, traversing, and tramming. Age was found to be a significant factor. Severity of injury, indicated by days lost, was found to increase with increasing age as well as with increasing experience, largely due to the confounding of age and experience. The operation of the roof bolting machine used in underground mining should be a research priority given the high frequency and severity of incidents. The results also suggest that temporal factors may exist, so additional research is warranted to better understand these factors and potentially develop interventions. This research provides a datadriven foundation from which future research can be conducted for safety interventions to reduce the frequency and severity of incidences involving the roof bolter activities of bolting, handling of materials, and setting the TRS.

Jan 1, 2016

By W. Bakiewicz

The Lower Indus Basin deposits form a substantial unconfined alluvial aquifer of excellent quality. This aquifer contains basically highly saline groundwater, overlain in places by considerable amounts of freshwater whose origin can be traced to the present and historical courses of the River Indus. In the past the main source of groundwater recharge has been direct river seepage and water tables were generally deep. Since the establishment of a perennial irrigation regime however, deep percolation from the increased irrigation supplies has predominated and the water-table has risen to within a few feet of the surface. The river system itself is being progressively developed for irrigation and very shortly a situation will arise where the entire low winter flow will be utilised. Fresh groundwater will then be exploited to supplement the surface supplies, and at the same time a drainage system, mainly based on wells will be used to stabilise the water-table at safe depths. This paper discusses some of the methods used to ensure optimum-economic development of the fresh groundwater and describes the general design philosophy evolved by the authors firms for both irrigation and drainage wells, with respect to both well configuation and operation. Water quality standards are discussed in as much as they affect subsequent use of the groundwater. A few particular aspects are considered, including that of the values of the relevant aquifer constants, the construction of wells and the determination of screen losses. A major problem solved during the Lower Indus Project investigations has been the design of wells to-produce fresh water from layers overlying saline water. This solution is also discussed.

Jan 1, 1967

By B. Whisner, A. Smith, J. Carr

"Electromagnetic based proximity detection systems (PDSs) are utilized on mining machinery to protect workers from being pinned or struck. These systems generate magnetic fields covering the space around a machine, and a miner-wearable component (MWC) detects the field. The PDS determines the distance of miners relative to the machine based on the detected magnetic flux density in the magnetic field. This information is used to establish warning and shutdown zones around the machine. Maintaining a stable magnetic field is essential for system accuracy. However, components used to generate magnetic fields can be influenced by temperature changes. Depending on ventilation conditions and seasonal alternation, a PDS can be subject to significant temperature fluctuation. To better understand and quantify this phenomenon, researchers from the National Institute for Occupational Safety and Health (NIOSH) developed an experimental apparatus to study the influence of temperature on magnetic field generator circuits used in PDSs. Results from the study show that the electric current through a generator can be influenced by both ambient and internal temperatures, modifying the magnetic field that is produced. These findings show that temperature can significantly influence the ability of PDSs, used in underground coal mines, to accurately determine a worker’s position in relation to mining machine. INTRODUCTION Electromagnetic based proximity detection systems have been developed to reduce machine-related accidents in underground coal mines. The first proximity detection systems installed in underground coal mines were developed for continuous mining machines (CMMs). There are five of such proximity detection systems that are approved for use in U.S. mines by the Mine Safety and Health Administration (MSHA) (Mine Safety and Health Administration, 2013; Mine Safety and Health Administration, 2015). There are several basic components that interact within an electromagnetic proximity detection system (PDS). A PDS includes two main elements: a set of generators to create magnetic fields around a CMM and a set of magnetic probes to detect the fields. These systems can determine if a miner is located at a safe distance from the machine based on the detected magnetic flux density. Stability of the magnetic fields is essential for system accuracy."

Jan 1, 2018

By Herman L. Bauer

The Robinson Mining District near Ely, Nevada, is one of the major porphyry copper districts in the world. Within the district is an east-trending zone of altered porphyry, metamorphosed sedimentary rocks, and sulphide mineralization surrounded by Paleozoic limestone, dolomite, shale and sandstone, Tertiary volcanics, and Quaternary alluvium. Six major disseminated ore deposits have been exploited in this eight-mile zone. About 20% of the district production has come from disseminated ore in metamorphosed sedimentary rocks found adjacent to altered quartz-monzonite porphyry. The following brief statements summarize the inter-relationship of porphyry, alteration, metamorphism, and mineralization: 1. Disseminated copper ore does not occur in unaltered porphyry or in unmetamorphosed sedimentary rocks 2. Sedimentary rocks have been only weakly metamorphosed where intruded, by unaltered porphyry. 3. Intensely metamorphosed sedimentary rocks are found only adjacent to, altered porphyry. 4. Many hydrothermal minerals are common to both altered porphyry and adjacent metamorphosed sediments. 5. Disseminated ore is found in altered porphyry and adjacent meta¬morphosed sedimentary rocks. 6. In general, there is a direct correlation between grade of ore in porphyry and copper content in the adjacent rocks. 7. Chemical changes in the altered porphyry facies and metamorphosed rock facies appear to be related:

Jan 1, 1963

By Vladimir J. Ovdenko, Sergey N. Lazarenko, Evgeny L. Schastlivtsev

The term sustainable development shortly appeared in international use in the run of UNO Environmental Protection Conference held in Rio de Janeim in 1992, bears the concept, that evolution process ( associated either with a region or society) should provide mutual interests concern in three aspects - environmental, economic and social ones, admitting as well the fact , that environmental protection should become an integral part of each process and cannot be regarded separately. In this connection it seems quite reasonable to employ the principal of sustainable development, while creating the model of industrial mastering the territory constraint lands viewing their future, for a example, in rich mineral deposit&apos;s development. In Kuznetsk coal basin in Russia ( west Siberia) the development of a big coal deposit Erunakovsky is now being underway. The major part of coal will be mined with open cast method, resulting the number of local environmental adverse impacts&apos; occurrence. In such a situation mastering of sustainable development model is given the top priority, demonstrating the essential result of its application in a form of possibility to define the best correlation between economically expedient and environmentally tolerable loads during coal mining. The given paper is an attempt to work out the main principals to approach the creation of sustainable development model in regard of the definite region case. To simplify the presentation of employed approach&apos;s main idea, the given below accepts as its component only one of many actually existing environmental profiles, that define mining pro- cess impact on environmental situation -the size of infringed (de- graded) lithosphere surface. Basically, the actually existed correlation between spheres. grounding the model of sustainable development - economic, environmental and social- is given in a form of nomogram under Fig.1. On the presented graph the prognostic values of broken lands relative extent within Erunakovsky boundary ( to be compared with total region area taken as 100%) are arranged on axis x". Axis "y- demonstrates the main values associated with complete economic background, making the intrinsic part of the principal for sustainable development, i.e. annual coal output for the given area. It&apos;s top, used in assessment value relates to actual showings implied for the study region project and quantifies 60 min. tons. While regarding the social facet of principal for sustainable development, the applied mode to separate social issues into two types - one profiling a welfare standard of living and the other. pertaining the way environmental situation contributes to the degree of &ologica-1 comfort in people&apos;s living was defined as the most expedient and the most adequate in the matter of reflecting the actual terms of vital activity of the society. In accordance with the cited above the economic level showings are plotted on the graph on "-x” axis, while "-y" one obtains the values associated with the point of ecological comfort presented in conventional units. For the maximum possible conventional point of living (corresponding in nomogram to 1.0 value) a welfare level secured with industrial region economic activity revenue was assumed in case the top planned annual amount of coal is delivered ( 60 min. tons). While studying the index of public economic welfare, environmental conditions corresponding level in its original state i.e. prior to any industrial work carried in the region, was adopted as its top possible conventional rating (1.0). The given nomogram displays the integrity of x-f(y) type interrelations plotted on the basis of four separate dependencies, precisely a) the size (area) of infringed earth&apos;s surface as a function of coal output in the region; b) subordination of ecological comfort of people&apos;s living to the degree of lands infringement; c) interconnection of economic and environmental components of people living; d) interconnection of economic level of people&apos;s living and the amount of coal mined in the region. Linked to a single unit, these separate plain dependencies create, as seen from the graph, a more intricate system of bonds, that affords during defining or changing this or that system parameter to secure undergoing changes, that occur to other parameters of the system. The mentioned reason made it possible to consider and drive to mutual conformity ( as far as it is possible) all parameters values for the defined system&apos;s relations, that in their turn indicate the concern of other aspects of a sustainable development principal. According to the graph, in order to get not more than 50% of infringed land left after the deposit&apos;s mining, it is advisable to ex- tract not more than 40 min. tons of coal annually, gaining in this case the level of ecological comfort for living in the amount of not

Jan 1, 1996

By Todd Minoski, KRISTIN FLOYD, Michael Murphy, VASU GANGRADE, Gamal Rashed, DYKE MARK VAN, Brent Slaker

Underground stone mines frequently operate on multiple mining horizons or are required to undermine or overmine old workings. In these situations, the effects of pillar columnization and interburden thickness on the stresses surrounding mine workings are poorly understood. Many old workings were not designed to consider the effect on future undermining or overmining and, as a result, are laid out on irregular patterns and with pillar sizes that are difficult or impossible to replicate on adjacent levels. Additionally, as depth increases, even a consistent gridded mine layout may result in poor columnization due to the need to increase pillar sizes. Rules of thumb and past practice for designing multiple levels may often be effective. This paper explores the effect that multiple-level stone mining has on stress redistribution through the discussion of two case-study mines and associated numerical modeling to provide additional insight into situations which may cause concern.

The National Mining Hall of Fame and Museum in Leadville, CO seized the opportunity to show off during its 10th anniversary induction banquet on Sept. 6. "We wanted to make people more aware of the mining hall of fame and museum," said Carl Miller, its executive director. The annual event honors inductees into the Mining Hall of Fame. This year, the inductees included Paul Wheeler Allen, Joseph Rosenblatt, Arthur Fay Taggart, Joseph Toy, Joseph Wharton and John Benjamin Zadra (ME, August, pp. 60-63). Allen, of Pasadena, CA and Rosenblatt, of Salt Lake City, are both living. Only Allen was able to attend. This year&apos;s induction banquet was the first held in Leadville, North America&apos;s highest incorporated city, at 3,094 m (10,152 ft) above sea level. The banquet gave attendees an opportunity to see the museum in its century-old 6,500-m2 (70,000-sq ft) Victorian schoolhouse. Many of the 350 guests came in 1890s dress to the black-tie affair. The evening included a cocktail reception and an open house along with a catered, prime rib dinner. During the open house, attendees had the opportunity to tour the museum&apos;s 12 rooms of exhibits and displays. Among items of interest, it was noted that a framed directory of inductees now enhances the entrance to the hall of fame. The directory is organized by the inductees&apos; names and the location of their plaques, allowing visitors to quickly find hall of fame members. Noted mining historian and author Duane Smith delivered the keynote address at the banquet. After the induction of the six honorees, attendees danced to the big-band era music of the Leadville 17-piece band BandAge. Karl Elers was the master ceremonies for the evening&apos;s program. He is a member of the hall of fame&apos;s board of directors and is chairman of Battle Mountain Gold Co. Allen was honored by the presence of 26 former colleagues and associates. He told the audience that he originally thought the museum should have been located in Denver. "But I have been proven wrong," he said. For many years, Allen was the operational executive of Cyprus Mines Corp. and a key participant in the company&apos;s growth. Allen received a replica of his mining hall of fame plaque from Thomas Falkie, chairman of the hall of fame&apos;s board of governors and president of Berwind Natural Resources Co.

Jan 1, 1997