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By Mark R. Bowie

Air-fall tuffs have been altered to zeolite via reaction of volcanic glass with local pore solutions at the six localities discussed in this paper. These are in the southern Basin and Range Province of Arizona and New Mexico, and in the Trans-Pecos and Coastal Plain regions of Texas. Zeolitization occurred in either closed- hydrologic, open-hydrologic, or hydrothermal groundwater systems. The tripping Spring Valley (DSV) chabazite in Arizona and the Buckhorn clinoptilolite in New Mexico originated in a late Cenozoic network of closed-hydrologic, lacustrine basins extending from southeast Arizona into southwest New Mexico. At DSV, two potentially commercial chabazite-rich tuffs are interbedded with lacustine mudstone. The main zeolite tuft contains up to 90 percent chabazite. The upper zeolite tuff averages approximately 67 precent chabazite. At the Buckhorn deposit, two clinoptilolite-rich tuffs are interbedded with lacustrine m udstone in the upper part of the Gila Conglomerate. The lower zeolite tuff contains up to 90 percent clinoptilolite. The upper zeolite tuff contains over 60 percent clinoptilolite. The Casa Piedra clinoptilolite is in the Trans-Pecos region of Texas. It formed during the Tertiary in a closed basin containing a playa lake. The Casa Piedra tuff averages about 60 percent clinoptilolite. Air-fall tuffs of the Cuchillo Negro, New Mexico and Tilden, Texas clinoptilolite deposits were zeolitically altered by either percolating ground waters in open-hydrologic systems or locally by ponded, saline, alkaline solutions. Cuchillo Negro tuffs are Tertiary and average approximately 50 percent clinoptilolite. Clinoptilolite-rich tuffs of Ebcene age have been mined from four quarries at the Tilden deposits. Tufts from the Kuykendall and Buck Martin quarries contain approximately 50 to 60 percent clinoptilolite. Low temperature, SiO2 - rich, hydrothermal solutions altered air-fall tuff to clinoptilolite and chabazite in the Foster Canyon area of the Tertiary Cedar Hills and Seldon Hills volcanic-vent zone in southcentral New Mexico. Poster Canyon tuffs contain up to 60 percent zeolite and average 40 to 50 percent clinoptilolite. The dominant mineral in the zeolite tufts at the six deposits studied is generally microcrystalline and either chabazite or clinoptilolite. Lithic fragments, unaltered volcanic glass, other zeolites, quartz, calcite, opal-CT, cristobalite, feldspar, evaporites, clays, and mafic minerals are also constituents of the tufts.

Jan 1, 1987

By J. H. Bassarear

Conventional crushing and grinding circuits are compared to semiautogenous circuits. Recent installations of each circuit are reviewed and seven methods of using autogenous or semi- autogenous techniques are described. Steel and power consmption data are reported and benefits of a dedicated digital computer are discussed.

Jan 1, 1981

By Y. L. Su

This paper describes a case study where solutions were sought to the truck queuing that occurred at a central processing plant. Ore from three production shafts at Falconbridge Limited's Sudbury Opera¬tions is hauled by three trucking contractors to Strathcona Mill. On return trips, the classified mill tailing is carried back to the mines for backfilling. The ore feeder at the mill handles three times the tonnage designed for and the situation is not expected to improve. Excessive truck queuing and consequent mine production interruptions are therefore of great concern. During the study, stochastic models were formulated and programmed for the IBM/AT personal computer. Basic information sought from the models were truck waiting time and ore production interruptions. The existing system was tested, not only to verify the validity of the models, but also to understand the causes of the problem. Several alternatives were simulated and a simple solution selected for implementation.

Jan 1, 1986

By Charles F. Herbert

The waves of prospectors who struggled across the wide Alaskan wilderness between 1898 and 19 10 came close to but did not actually find the rich copper/zinc/silver deposits strung out along 161 km ( 100 miles) of felsic schist in the remote Brooks Range of northwestern Alaska. They had heard rumors of gold in the valley of the Kobuk River, so they skirted the Arctic ice pack in the Chukchi Sea and, in a force at least 800 men strong, ascended the Kobuk River in 1898. Twenty-eight placer mining camps were established but only a handful survived for more than a few years. One of the placers that died rapidly was Ruby Creek. A map showing the location of Alaskan mineral deposits is given in Fig. 1. The Ruby Creek miners, disappointed with the scarcity of gold in that creek, followed copper-bearing float to two places where the float was especially plentiful. Pits, a short adit, and a shallow shaft uncovered copper carbonates, bornite, and chalcopyrite in fractured limestone but the remoteness of the district blocked efforts to sell the claims or to raise capital for development. Shortly after 1906, the copper prospects were abandoned and, except for an account published in 1913 by the US Geological Survey, they were forgotten, as were the names of the prospectors.

Jan 1, 1991

By L. J. Prosser, A. T. Iannacchione

Unfortunately from 1991 through 1995, 44 miners were fatally injured in the stone industry. Of these 12 occurred at underground mines from a total work force of less than 2,000 miners. Nine of these 12 miners were fatally injured in falls of roof or rib. A safer environment for the miners can be achieved by evaluating the nature of the hazardous ground and by developing more efficient and effective ground control strategies. Roof and rib conditions in the underground stone industry were observed and assessed at 33 mines in Illinois, Indiana, Kentucky, Maryland, Missouri, Pennsylvania, and West Virginia [(Figure 1)]. Hazard assessment indicated that those ground failures occurring under moderate to substantial overburden (> 30 m [l00 ft]) were caused by stress concentrations and geologic structures. Ground failures near the surface are caused by solution (water) processes. Selection of the mining horizon and mine layout decisions tremendously influence ground stability.

Feb 24, 1997

By W. Kuckshinrichs

Metallic raw material flows are characterized by a complex global network of producers and consumers, as well as by a multitude of ecological, economic and social impacts across national boundaries and on different scales. This leads to the need to develop methodologies, which allow identifying obstacles that prevent metallic raw material flows to contribute to sustainable development. From a scientific point of view CRC 525 (Martens 2003) has developed an holistic indicator set consisting of approximately 80 different indicators. This set is taking into account the multi-dimensional character of sustainable development. Moreover the indicators reflect different system boundaries according to different actor levels and decision contexts. The full indicator set is important in scientific considerations and suitable for scientific awareness creation. However, to fulfil the function of a decision support approach for political and economic decision-makers some modifications are of central concern. At first a reduction of the full indicator set by selection of core indicators enables decision-makers to deal with complex issues of contrary economic and societal protection targets. Secondly, as thresholds of indicators justify societal call for action, they are discussed against its political or scientific origin. The proposed methodology is exemplified by indicator-based studies of the material flow of aluminium.

Jan 1, 2003

By N. Paas

Diesel powered equipment has been operated in underground coal fir mare than 50 years. According to the Mine Safety and Health Administration (MSHA), there are approximately 3,000 diesel units operating in underground coal mines in the United States. This number is expected to reach 5,000 diesel units in 250 coal mines by the year 2000. Also, there are approximately 5,000 diesel units operating in metal/nonmetal mines such as trine, potash and salt mines: and more than 3,000 diesel units operating in Canada. This increased popularity of diesel powered equipment over trolley wire, electric trailing cable or battery powered equipment is because of improved safety, greater mobility, higher productivity and increased power of diesel equipment. The operation if diesel powered equipment is not without challenges. Diesel engines generate exhaust emissions, in particular carbon monoxide, oxides of nitrogen, sulfur dioxide, unburned hydrocarbons, and diesel particulate matter that must be maintained at safe levels. The chief method to control ambient exposure has been dilution by ventilation. A new concept to ensure continued safe ambient emissions levels from diesel equipment in underground mines is the EMISSIONS MANAGEMENT PROGRAM™. The program encompasses all factors that will influence diesel emissions. By ESTABLISHING low tailpipe emissions through technology, such as clean engines, clean fuel selection, exhaust aftertreatment devices and filtration of the exhaust gases via the Dry System ™, this program ensures that the baseline emissions are at their lowest technically feasible concentrations. The DST Dry System™ exhaust conditioner reduces DPM by over 98%, as demonstrated through laboratory research at the West Virginia University. Carbon monoxide and hydrocarbon emissions and odor are similarly reduced. MAINTAINING these low emissions requires an expanded training program for operators and mechanics, onboard feed-back devices and a maintenance program with special focus on events and faults that can alter emissions. Finally, an on-board emissions sampling system allows the mechanic to VERIFY emissions levels and help diagnose engine faults. If the tailpipe emissions fall outside an established limit for a particular equipment, corrective actions will be initiated.

Feb 24, 1997

By Jeffrey K. Whyatt

The Crandall Canyon accident investigation included an interesting and unexplained observation by rescuers that the ?barrier rib had shifted northward as a unit, as much as 10 feet.? This is not the first mention of such a movement, although such reports are rare. Historical accounts describe unusual movement and displacement of intact coal, cribs and timbers. Two movements of particular interest are the creation of gaps above coal pillars and falling of standing support elements without apparent damage. A dynamic boundary element program was used to explore movements induced by slip on geologic features removed from the affected panel. While the resulting models are much too simple to fully replicate these observations, they do show that the types of phenomena observed are possible. They can also provide insight into the types of motions that ground support elements are subjected to during large bump events. This was demonstrated for the case of a large bump in a Book Cliffs coal mine. Seismic information suggested the source mechanism to be normal slip on a fault. A model of that source showed initial dilation of the panel followed by dynamic compression and rebound ? consistent with underground observations. The initial dilation is important as it may allow slender standing support to shift or fall.

Jan 1, 2009

By Christopher Haycocks

Because of growing pressure from government and consumers to produce more coal, the mining industry must improve existing techniques and devise more efficient mining methods. Mining of the thicker, shallower and geologically superior coal seams in the western United States is being subjected to increasing pressure from environmentalists; and so in order to meet the demand, the coal industry is exhausting the more accessible surface seams and beginning to mine seam of over 1,000 feet in depth and less than. 30 inches in thickness. The longwall mining system is the natural choice for extracting deep and thin coal seams, as it operates almost independently of the overburden rock stress. Due to the added fact that longwall mining is an inherently more productive method than room and pillar mining, many coal producers are looking to it as a means of increasing productivity without a corresponding cost increase. The consistent rise in application of longwall mining in the United States in the last decade illustrates the excellent potential of this technique for the future. American mining conditions are geologically different from those in Europe where longwall mining has been highly developed and extremely successful. Although numerous successes have been recorded in the U.S. with this mining system, a substantial number of failures have also occurred. These failures are due primarily to roof control problems usually over the face, in the tail entry, or both. Another problem area for American operators contemplating the use of this method has been correct selection of equipment, which should be custom fitted to local mining conditions for optimum productivity. It is essential that correct estimates for chock resistances, support densities, supported and unsupported roof spans, as well as rates of advance and length of working faces be provided to optimize mining conditions. Unless extensive pilot projects are planned engineers must choose their equipment correctly at the outset. A typical investment in longwall equipment will amount to several millions of dollars.

Jan 1, 1979

By Rajiv Hadkar, M. D. McKinley, J. B. Hiskey, B. J. Scheiner, G. W. Warren

Flyash from municipal solid waste incinerators containing roughly 13 to 15% Zn, 2% Pb and 0.2% Cd is an attractive material for simultaneous metal recovery and detoxification. Results have shown that Pb in flyash is present as PbSO4 and PbC12 and that about 70% of the Zn is present in the form of soluble amorphous compounds. Leaching results in a number of acid and basic lixiviants show that acid leaching is clearly more effective than basic leaching which is limited by low solubility of Cd and Zn. Cementation in acid solution with pH < 1 promotes redissolution of the precipitated metal. Successful zinc electrowinning from chloride leaching solutions has also been demonstrated, although Pb2+ and Na+ can be potentially detrimental. The presence of Pb2+ can prevent deposition of metallic Zn, forming zinc oxychloride, ZnC12.4Zn(OH)2, instead. High concentrations of Na+ can also result in precipitation of NaCl. This investigation has shown that hydrometallurgical treatment of MSW flyash through leaching, cementation and electrowinning is a potentially feasible method for simultaneous detoxification and recovery of metal values. Several issues have also been identified which would require further investigation for final process development.

Jan 1, 1993

By Christian Maguire

Tunnel contracts in New York have in recent years had few bidders with the bids received being much higher than anticipated. Since 9/11, security has become a key issue in planning key infrastructure projects in New York. This is especially true in the case of large water supply tunnels. Striking the right balance between cost and security was the major factor in determining the best configurationfor the Kensico-City Tunnel. This paper outlines the efforts made to determine realistic probable bid costs for the tunnel contracts, and the innovative approaches taken to deal with security issues.

By T. K. Kim

Iron, cobalt, and nickel in waste ferric chloride solutions were separated from each other by solvent extraction. The iron was extracted from the cobalt and nickel by the use of methyl isobutyl ketone, and then the cobalt was separated from the nickel by the use of a high-molecular-weight quaternary amine dissolved in a solvent of high aromatic content.

Jan 1, 1980

By M. E. Ryan, C. L. Hoebbel, E. J. Haas

DISCLAIMER The findings and conclusions in this paper are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of any company or product does not imply endorsement does not constitute endorsement by NIOSH. ABSTRACT It has been suggested that effective disaster prevention and response in mining requires that elements of emergency management be incorporated into everyday operations, planning, and decision-making, much in the same way that the industry approaches routine risk management. Since Congress passed the MINER Act in 2006, the newly mandated structural and technological advancements in mine emergency response preparation have been made and are apparent, but measureable improvement in mineworker emergency preparedness is difficult to ascertain. To begin exploring whether measurable indicators of mine workforce preparedness can or should be addressed within a risk management framework, NIOSH researchers examined the datasets from two separate research efforts—one which measured the organizational safety climate and self-reported safety performance, and the other which measured individuals’ perceptions of their own self-escape competency. INTRODUCTION In response to the mine disasters in 2006, the United States Congress passed the Mine Improvement and New Emergency Response Act (MINER Act), which strengthened existing regulations [30 CFR, Part 48] and introduced new provisions to improve mine emergency response. Since that time, new technological and structural features, such as mandated redundant communication systems, personnel tracking systems, and lifelines in primary and secondary escapeways, have been installed in underground coal mines across the country. Additionally, mine operators are required to develop emergency response plans, provide adequate supplies of breathable air throughout the mine, provide more frequent and realistic expectations training, and are required to immediately notify the Mine Safety and Health Administration (MSHA) in the event of an accident. While the structural and technological advancements in emergency preparedness are readily observable and easily measured, levels of individual mineworker preparedness remain difficult to assess. There is a general consensus that deficiencies in competence in the non-routine tasks required for individual miners to effectively respond to a mine emergency likely remain (e.g., National Research Council [NRC], 2013), and NIOSH research continues address this concern (Haas, et al., 2015; Hoebbel et al., 2018). To maximize an operation’s capacity to effectively prevent disasters and/or respond to emergency events, it has been suggested that individual and emergency management efforts be incorporated into everyday operations, planning, and decision-making in much the same way organizations manage routine risks to health and safety (Haddow et al., 2017). To the authors’ knowledge, the mindful intersection of routine risk management policies and practices and emergency prevention and response readiness have yet to be empirically studied within the mining industry.

Jan 1, 2019

By A. Founie

The United States continues to be the world’s leading producer and consumer of diatomite. Production of diatomite in the United States during 2005 was estimated to be 653 kt (720,000 st). This was a 5-percent increase compared with 2004. The value of processed diatomite in the U.S. was about $179 million in 2005. Production was from six companies with 12 processing facilities in four states. California and Nevada were the principal producing states. They accounted for about 70 percent of U.S. production in 2005. U.S. diatomite exports were about 144 kt (159,000 st). Imports were negligible. The internal structure and chemical inertness make diatomite an excellent raw material for filtration, absorbent and filler applications. Filtration, especially the purification of beer, liquors and wine and the cleansing of greases and oils, continued to be the largest end use for diatomite. Other applications include the removal of microbial contaminants, such as bacteria, protozoa and viruses in public water systems, and the filtration of human blood plasma. The use of diatomite as fillers and in pharmaceutical applications, including the filtration of human blood plasma, continues to increase as has its use as an insecticide base and as pozzolan. The relative rank of end uses of diatomite were filter aids, 75 percent; fillers, 11 percent; absorbents, 7 percent and other (mostly cement manufacture), 7 percent.

Jan 1, 2006

By C. V. Trang, V. T. Le, K. Enns, J. J. Byerley

The precipitation characteristics of copper and nickel cyanides from solutions continuing copper zinc and nickel cyano complexes are examined. Equilibrium precipitation calculations are presented as well as comparative experimental data. The practical significance of the precipitation data is discussed in the co·ntext of an initial step m an overall treatment strategy for mixed cyanide effluents.

Jan 1, 1998

By Alfred Weiss

Selecting a minicomputer is not unlike selecting a costly piece of mining equipment such as a truck, shovel, crusher, or conveyor belt system. A marked difference might lie in the frequency at which such selection takes place; another difference might be mine management&apos;s familiarity with mining equipment vis a vis a minicomputer. These basic differences might prompt a mining company to seek the aid of a consultant when selecting a minicomputer system. Advantages and Disadvantages The fundamental advantage of employing an independent consultant is that it provides management with a source of knowledge and breadth of experience not readily available within the organization. If the consultant has a minerals background, such knowledge and experience are further enhanced by actual experience in exploration, mining, and mineral processing. If the consultant has worked within a mining company, such hands-on experience is supplemented with a meaningful understanding of the client&apos;s business; this facilitates communication between the consultant and members of the client organization. The consultant has been, so to speak, "in the client&apos;s shoes." There are several other advantages. Since computer systems cut across organizational boundaries, the independent consultant may be able to move within the organization more easily than an inside staff person to collect necessary information. Also, detachment from any manufacturer should provide the client with an objectivity and a set of recommendations as near optimal as feasible. The principal disadvantages lie in the area of continuity and accountability. Once the consultant&apos;s report has been submitted and his recommendations implemented, a discontinuity might occur. Also, if implementation does not provide the desired results, the consultant might not be available to correct the situation or account for actions taken. Proper selection of consultant services, relative to kind and duration, and the consultant&apos;s method of operation, will often prevent many of these aftereffects. Services Offered The professional consultant can help a client: •Define and summarize information systems technology* needs; • Evaluate alternatives such as in-house capability and capacity, time-sharing, or service bureaus; • Prepare a formal request for proposal (RFP) to be submitted to vendors; •Evaluate vendor proposals; •Evaluate the economics of lease vs. purchase; and •Assist in the conversion and installation. Thus, consulting services may range from evaluating an existing system and upgrading to a larger piece of equipment, to selecting a new first-for-the-organization computer. First, Define and Summarize Needs Regardless of circumstances, the most valuable document required before equipment selection is the information system plan (I/S plan). It helps insure that the company&apos;s information needs are met in a cost-effective manner. An I/S plan is usually a comporient of the mining company&apos;s overall business goals. Since an I/S plan is a formal vehicle for establishing and communicating the direction the organization intends to take to satisfy information requirements needed to achieve goals and objectives, most initial systems services are likely to center around creating such a document or updating an existing document. The trend toward company-wide I/S planning is increasing in the mining industry; however, smaller scale efforts focused at the information systems needs to support an individual

Jan 11, 1981

By Weijian Yu, Jianbiao Bai, Jinlin Xin, Shiqiang Xu, Shuai Yan, Zizheng Zhang, Hai Wu

The retained roadway subjected to dynamic loading from thick and hard roof (THF) fracturing caused severe deformations in the thick coal seam (TCS). Understanding the dynamic loading mechanism of gob-side entry retaining (GER) in TCS with THF is the first step in determining the stability of the retained roadway. Characteristics of dynamic loading mechanism of gob-side entry retaining (GER) in TCS with THF are investigated through numerical simulation and field test of 150208 haulage gate in Sucun coal mine. To improve the reliability of numerical simulation, the double-yield model is used to simulate gob and the strain-softening model is used to simulate filling body; the dynamic module in FLAC3D is used to simulate the dynamic loading due to the THF fracture, and the global model are validated. Characteristics of surrounding rock convergence, plastic zone distribution, and vertical stress in the filling body after the THF fracture are reveled with respect to width to height ratio (W/H) of the filling body and the dynamic loading strength of the THF. The rational width to height ration of the filling body constructed with high-water materials is 0.57. Field monitoring results show that the GER with THF in Sucun coal mine could adapt the dynamic loading due to the THF fracture and meet the requirement. This study is helpful to better study the stability of GER according to the breaking dynamic load of THF and provides reference and guidance for the analysis of breaking dynamic load of THF under similar geological conditions.

Feb 23, 2023

By Claus Becker

Waterbearing, cohesive or non-cohesive grounds with glacial stone deposits are found very often in Europe. The problem consists of destroying the boulders and supporting the face simultaneously. At the example Grauholztunnel Bern ( outer diameter 11,60 m ) the theoretical attempt of solutions for the big machines is described: destroying of the boulders with roller discs, hydraulical support of the front. The problem of coming out of stones of a certain size from the surrounding matrix will be discussed. Further diminishing to the size that can be handled by pumps is executed by a crusher, situated in the center of the machine. At the same example the theoretical attempt for headings in cohesive soil with stone deposits are shown. Surface structure of the cutting wheel and working chamber as well as controllable current movements are the solution here. The danger of clogging discs and stone crusher has to be encountered by right positioning of the tools and jetting nozzles. At the example Sewer MoosstraBe Salzburg the same problems are discussed for the Mikro-Tunnels. The pipe-jacked sewer lines have outer diameters from 485 and 805 mm. With this method, the stones have to be holed through. The wear of the cutting tools determines the [ ]

Jan 1, 1989

By Sotiris N. Kamenopoulos, Zach Agioutantis

Rare earth elements (REEs) are considered critical minerals for industrial and defense sectors. REEs are not as rare as the word “rare” portrays; yet, the exploitable and/or profitable deposits of REEs may be found only in certain geographical areas. The political and social conditions characterizing these areas may not always be in favor of mining operations. These conditions are imposing the need for extra consideration on the geopolitical constraints prior to any decision-making and before any mining project begins. This study assesses the risk related to mining projects for areas that feature REE deposits based on a geopolitical viewpoint. Probable ranking differences between the current assessment and a 2015 assessment are discussed. The comparative indicators used and the appraisal procedure applied in this comparison are based on a number of different geopolitical indicators. Several ranking changes occurred between 2015 and 2019.

The United States is being invaded... by foreign capital: marks, francs, pounds, yen, lire, riyals, you name it: On almost any given day the Wall Street Journal will contain a new report on a department store, newspaper, bank, hotel, agricultural land, supermarket chain, et a1 being bought into by overseas investment. Xenophobic reaction to this revised national condition has begun to set in. Several farming states have and are introducing legislation to monitor foreign land buying. In Congress a mandatory reporting requirement for foreign purchasing is currently under study. In a relatively short period the country has reverted from world leader- ship in overseas acquisition and involvement to become itself one of the prime investment opportunities in existence. Interestingly enough, one of the industries where this changed status has become most apparent and pronounced is within that small/regional/segmented/low value-to-weight bulk commodity enterprise ranked as the backbone of the nation&apos;s construction activity. U.S. cement making is not only undergoing internationalization in its ownership, but also in its product, equipment, and engineering expertise.

Jan 1, 1979