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By Michael F. Roach, Joseph K. Cavey, Gary E. Taylor

A rigorous horizontal drilling and chemical grouting program was specified beneath the Hollywood Freeway (U.S. Route 101) section of Los Angeles Metrorail Contract C-311.Twin 6.67-m (22-ft.) diameter starter tunnels were to be conventionally mined through amixed alluvial and bedrock face consisting of silty sand, gravel, and weathered sandstone and siltstone of the Topanga Group. The contact between the alluvium and bedrock dipped toward the Crossover Excavation where the horizontal drilling and grouting operations were performed. The intent of this grouting program was to stabilize the mixed face to minimize ground loss and surface settlement, and to reduce groundwater inflow into the tunnel headings. Given the highly variable mixed face conditions, horizontal drilling up to 86 m (284 ft.) resulted in upward trending trajectories which likely followed the bedrock contact. Chemical grouting was performed in a primary, secondary and tertiary, three dimensional sequence. Evaluation of the primary and secondary grouting parameters indicated where tertiary grouting was required. Grouting pressures induced a small rock failure at the tunnel heading as well as increased stresses on the tiebacks of the excavation.

Jan 1, 1997

Presiding was Robert E. Murray. The first speaker was Frank L. Natta, Administrative Manager-Trapper Mine, Utah International, Inc., Craig, Colorado. Subject - "Long Term Coal Contracts." Mr. Natta graduated in 1973 from Colorado School of Mines with a B.S. in Metalurgical Engineering and a M.S. in Mineral Economics. Since 1974, he has been employed by Utah International having spent 5 years in San Francisco as Senior Market Analyst. In this capacity he was responsible for market development efforts for Utah's U. S. coal reserves. Recently, he was transferred to Craig, Colorado, as Administrative Manager of Utah's Trapper Mine. In this position, he is responsible for purchasing, warehousing, accounting and sales contract administration. The second speaker was Brucks Mitchell, President, Human Resources Management, Inc. Richardson, Texas. Subject-"Making Unions Unnecessary in the Coal Industry." Mr. Mitchell has a B.A. degree in English-Oklahoma State University. M.B.A. degree in Organizational Behavior-Southern Methodist University. Ph.D Candidate - Organizational Behavior - North Texas State University. Mr. Mitchell formed an Association of Consultants to perform assignments in Industrial Psychology and Human Resources Management. Particular emphasis has been to establish policies and procedures to make labor unions unnecessary. He has been consultant to various industrial and municipal organizations.

Jan 1, 1979

By A. B. Cecala

Enclosed cabs have been used for many years to isolate workers on mobile equipment in the mining industry for health and safety reasons. These enclosed cabs create a microenvironment for workers where they can be either more protected or more vulnerable to contaminants. Over the past decade, the National Institute for Occupational Safety and Health (NIOSH) has performed substantial research efforts to improve the air quality inside enclosed cabs of both underground and surface mobile mining equipment. In these efforts, NIOSH has partnered with mining companies, original equipment manufacturers (OEMs), and manufacturers of filtrations and pressurizations systems in a synergistic effort to reduce respirable dust and improve the air quality inside these enclosed cabs. Various field studies over this time have shown an array of results ranging from very minor to very significant reductions (protection factor: 3 ? 89) in respirable dust levels inside these enclosed cabs. In addition to and concurrent to the field work, NIOSH also performed a comprehensive laboratory study to evaluate all the factors involved in cab filtration and pressurization systems and identified those factors that were most significant for an effective system. From this comprehensive research effort, the key components for an effective filtration and pressurization system have been identified in an effort to provide the best air quality, thus minimizing the respirable dust exposure, to equipment operators inside of enclosed cabs of mobile mining equipment.

Feb 27, 2013

By V. V. Nazimko, A. I. Hohotva, S. N. Alexandrov, V. P. Sazhnev, V. S. Zaharov

Ground behaviour in the vicinity of a roadway has been investigated using a physical model and in situ tests during a roof fall. It was discovered that behaviour of the ground is governed by irreversible displacements of adjacent rock clusters. The cluster is a short-living sector of a rock mass that moves as a solid body. For the lack of degree of freedom, the rock mass must be divided into clusters that are forced to move one after another in space and in time. These clusters permanently rearrange and reform during irreversible (inelastic) ground deformation. The crowded clusters have to yield to each other and alter their velocity and direction of movement to accommodate their motion into the excavation. Such behaviour involves uneven and irregular vertical deflection and the movement of adjacent rock blocks in the roof, sides and floor of an opening. Such movement destroys the symmetry of horizontal displacements with respect to the centre line of the opening. A set of indicators that a roof fall is imminent has been identified. Horizontal displacements and dilation must be controlled in order to maintain the stability of an underground opening. Such a state retains the self-supporting effect of the roof and contributes to rock bolts bearing capacity.

Jan 1, 2003

By James H. Jolly

Although zinc in the environment is generally considered to be beneficial or benign, excessive amounts can cause deterioration of environmental quality and toxicity problems for some plants and animals. High amounts of zinc in the environment are often associated with anthropogenic activities, mainly those involving zinc production and consumption and those related to the use and disposal of zinc-containing products. To obtain some upper limit parameters on the historical quantities of zinc chat may have entered the U.S. environment from anthropogenic sources, the Bureau of Mines conducted a materials flow study of zinc from the earliest beginning of the domestic industry through 1990 and for the year 1989. For comparative purposes a generalized historical materials flow of zinc for the world was also prepared. The United States was the world's leading producer and consumer of zinc in the 1850-1990 period. In that period, U.S. mines and smelters produced 15% and 20%, respectively, of world output, and U.S. zinc consumption accounted for about one-fourth of the world total. Maximum zinc losses into the environment related to the above production, consumption, and disposal of end use products total about 63 million tons. Dissipative uses and landfill disposal have accounted for about 73% of the potential zinc losses to the environment, followed by mining and smelting 22%, and manufacturing, 5%. At the end of 1990, contained zinc in useful end-products in the United States was estimated to be about 23 million tons. In 1989 slightly more than 1 million metric tons of zinc in new zinc-containing products were added to the domestic pool of zinc in use but in the same year, an estimated 0.9 million tons was dissipated and discarded, indicating only small net gains to the zinc pool of use annually.

Jan 1, 1992

By Thomas A. Bailey

Since the advent of longwall mining, various methods and materials have been used during relocation to control the intrusion of the gob in the shield/panline area. (figure 1) Controlling this gob is critical to ensuring a safe, speedy, and productive longwall move. An uncontrolled gob can cause a number of problems, from increased worker exposure to entrapment of equipment to lost production. With an eye toward worker safety and increased productivity, several different methods have been developed to minimize gob intrusion. This presentation will take a look at the history and development of longwall ?screens? and ?mesh?, from chain-link fencing to high-modulus polyester geogrids. The benefits and advantages of these developments will be defined. Since 1994, longwall coal mines have used polymer geogrids during longwall recovery to control intrusion of gob material into the shield/pan line area. As described by Brandon and Collins (1996) in their paper presented at the 15th Ground Control Conference in Golden, CO., mines had used various forms of support, such as welded wire mesh, chain-link fencing, wooden cribbing, props, and steel cable to accomplish this. These methods worked, but were labor-intensive, slow, and provided varying degrees of gob stoppage. Although a few mines still use chain-ink fencing to control the gob, longwall coal mines have generally settled on polyester geogrids to control gob and roof and these mines have been instrumental in providing input in order to develop and improve these geogrids products. he trend during the past twelve years has been to incorporate stronger grids and to eliminate auxiliary reinforcements, such as steel cables and nylon or polyester webbing. A job that once required heavy steel cables, props, and fencing is now accomplished with strong, lightweight, high-modulus polyester grids. When we discuss high-modulus grids, we refer to the ratio between load and strain, as illustrated in figure 2. These grids are woven or knitted from yarns that have been pre-stressed. When these grids come under load, they pick up the load more quickly. This allows less deformation in, in this case, the mine roof. The same principle applies when these grids are used to control the ribs. With less elongation, the grids will hold rib material tighter, thereby keeping travel ways more open.

Jan 1, 2006

By Tetsuo Yamazaki

Metal market prices rose drastically in 2006, and most broke historical records as shown in Figs. 1-4. This increase has been basically driven by economic growth in Asian countries, especially China. The growth trend is expected to continue for several years. Then, India will follow the same growth trend. Their metal demands keep the price levels high for 20 years or more. One more additional important factor on the metal market prices is hedge funds come into the market. Japan imports all metals for domestic use from overseas. The amounts imported were 1.27 million tons in copper, 0.32 million tons in lead, 0.59 million tons in zinc, 0.20 million tons in nickel, and 1.18 million tons in manganese, respectively in 2006 (Source: http://www.jogmec.go.jp/j_resourse/index.html#03). Though mainly we import the concentrates and our domestic customer smelters take the part of metallurgical leaching, the payment necessary for purchasing the concentrates is estimated about US$ 10 billions in 2006. The payments in 2005 and in 2003 were about a half and a quarter of the 2006, respectively. Japan must have effective counter measures to reduce the future payments.

Sep 24, 2006

By Mark Colwell, Christopher Mark

This paper summarises the results of a research project whose goal was to provide the Australian coal industry with a rib support design methodology and software tool that could be utilised by suitably qualified colliery staff. The project was primarily funded by Australian Coal Association Research Program (ACARP) and further supported by several Australian longwall operations. The outcome of the project is a design methodology and software tool called, Analysis and Design of Rib Support (ADRS). ADRS is an empirical technique, which recognises that several geotechnical and design factors affect ribline performance and in addition that operational and safety issues essentially dictate the level of performance required. Therefore, the design recommendations associated with ADRS are specific to the Australian coal industry; however the procedure(s) for data collection and analysis could be applied to other countries' 'underground coal industries. Case history data were compiled from 34 longwall and two bord and pillar operations resulting in 204 case histories with each case history data set being defined by approximately 130 individual data fields. In addition monitoring (incorporating stress cells and extensometers) was undertaken at 10 collieries to assess and quantify the effectiveness of different rib support patterns and hardware on rib performance. The monitoring sites allowed for an improved understanding of the mechanisms of rib failure and degradation in terms of its interaction with the installed support and at the various stages of the mining cycle. The design methodology deals with both mains development and gateroad development specific to Australian longwall mines. This paper focuses on longwall gateroads subjected to abutment loading and in particular the travel road which becomes the tailgate of the subsequent panel. The statistical analyses associated with these cases suggested that the level of rib support should be based primarily on the development height and the pillar stress level. The ADRS software guides users through the design process, allowing them to develop rib support plans based on sound science and a broad base of in-mine experience To the best of the authors’ knowledge ADRS is the first systematic rib support design technique to be developed for any country’s underground coal industry. The development and use of empirical models in mining have substantially contributed to improving safety and productivity. ADRS further demonstrates that empirical techniques are particularly relevant and beneficial in dealing with the complexities of geotechnical design associated with underground coal mining.

Jan 6, 2008

When overburden depth exceeds economical recovery in openpit coal mines, the use of highwall mining systems has increasingly come into play. However, stability in the highwalls is always a major safety concern during such mining. The U.S. Mine Safety and Health Administration requires that highwall mining operators follow ground control plans that specify the pillar sizes necessary to prevent collapse that would threaten highwall stability.

Jan 1, 2006

The morning session opened at 9:00 a.m. and was presided over by Mr. Don Ross, Manager of Mines, Kaiser Steel Corporation,- Sunnyside, Utah. The first speaker was Mr. S. W. Zanolli, Partner in Law Firm of Webster and Kilcullen, Washington, D.C. Mr. Zanolli was born and raised in a coal mining community of Fredericktown, Washington County, Pennsylvania. He was educated at Washington and Jefferson College and graduate schools of the University of Pittsburgh. He served as an infantry officer in the European Theatre of operations during World War 11. He worked as' a handloader at Vesta No. 5 Mine of Jones & Laughlin during summers while attending Washington and Jefferson College. He worked at a variety of production jobs at No. 7 Mine. of Island Creek Coal Co. of Holden, West Virginia. Assigned to a variety of industrial relations assignments at Island Creek Coal' Company during 1949-51, attaining position of Supervisor of Personnel and Labor Relations. Served in many industrial relations assignments at U.S. Steel Corp. headquarters during 1953.-1967, attaining a position of Personnel Director-Heavy Products Operations. In January, 1968" he became a member of the Bituminous Coal Operators Association-as Executive Vice President. This past year he went back to practicing law and is a member of the Law Firm of Webster and Kilcullen, Washington, D.C. He is married and has five children.

Jan 1, 1973

By Roy Lindsay, Paul O'Hara, Gary Halverson

"The New Britannia Minesite is located in Snow Lake, Manitoba, 420 miles north of Winnipeg (figure 1). The mine previously operated from 1949 to 1958 extracting some 5.39 million tons of ore at a 0.150 opt gold grade. From 1959 to 1986 the property was held by Nor-Acme and Hudson Bay Exploration and Development and in 1987 High River Resources Ltd. Optioned the property, dewatered the mine and conducted a diamond drill program between the 1 780 and 2400 levels. In 1988 two companies, Nor-Acme Mines Ltd. and High River Gold Mines Ltd., negotiated an option agreement with INCO Gold whereby !NCO assumed management control of all site exploration work. During this period, a bulk sample of 10,000 tons was extracted from the 1780 level with no further exploration recorded after its removal. Both Hudson Bay Exploration and Development and INCO Gold conducted feasibility studies on reactivating the property but at a calculated capital cost of Cdn $70 to $80 million found the rate of return on their investment unacceptable.In 1991 !NCO Gold merged its interest with the assets of TVX Gold Inc. and in February 1994 TVX Gold Inc. and High River Gold Mines Ltd. entered into a joint venture partnership to develop the Snow Lake property, naming TVX Gold Inc. the operator. Upon completion of a feasibility study in April 1994 by Bharti Engineering Associates Inc., a decision was made to reopen the Britannia Mine at an established project cost of US $33 million.Project construction commenced in July 1994 with the hoist house excavation. The first concrete for the hoist house level footings was poured on August 4, 1994 and the project was completed on October 1, 1995 at a cost of US $36 million. The first gold pour took place November 4, 1995.This paper not only presents the metallurgical aspects of the operation but also describes the novel approach used to complete the design and construction of the site facilities."

Jan 1, 1996

By Hyung-woo Kim, Sup Hong, Sung-Soo Kim, Chang-Ho Lee

A deep-seabed integrated mining system, which consists of four subsystems such as riser pipe, buffer, flexible riser, and tracked vehicles, is presented in Figure 1. In order to collect more manganese nodules, multiple tracked vehicle systems should be used in a deep-seabed integrated mining system.

Sep 1, 2014

By P. F. Allen

WITH capacity of 51,000 tpd, the Morenci concentrator produces approximately 49,000 tons of tailing for final deposition. Disposal involves distribution of thickened tailing to dams in such a manner that solids can be used for dam construction and water can be impounded for reclamation. During early operation, although tonnage treated was lower, it was necessary to use orthodox disposal practices in the areas available for tailing. Trestles mounted on a series of dams, constructed of borrow material, carried the pipelines from which tailing were spigoted behind the dams. When adequate disposal areas were finally established, it became desirable to look for more efficient methods. The idea of placing the distribution pipe or manifold directly on the crest of the dam was advanced in 1945. After a period of testing, that procedure in modified form replaced the older trestle arrangement. Marked economies resulted, and time required to prepare dams for succeeding storage cycles was greatly reduced. The tailing disposal area for the Morenci concentrator lies south and southwest of the concentrator building. Ample storage space is available. A wide valley contains three sharply defined ravines lying on an average slope of 4 pct. The more central of these ravines, and the largest of the three, is known as Morenci canyon, which provides substantially more tailing storage area than the other two. Stargo canyon lies to the west; the other is appropriately named East canyon. Total area of the tailing disposal site is nearly 31/4 sq miles, or about 2000 acres. The storage area in use was somewhat more than 850 acres at the end of 1954, or 16 acres per 1000 tons of tailing to be stored daily. At the present time none of the east side dams are in regular use but they are available in emergency. There are five dams on the west side (in Morenci and Stargo canyons) as well as two auxiliary dams adjacent to No. 4 West and No. 5 West. This has made it possible to concentrate men and equipment in a smaller area with consequent savings in both manpower and machinery. Tailing Thickening: Tailing from the flotation process reaches the thickeners with a solid content of about 18 pct. The launder carrying this pulp is subdivided at a central point into seven launders carrying a proportional share to each of seven tailing thickeners, which are located in Morenci canyon close to the concentrator. Five of these thickeners are 300 ft diam and two are 325 ft diam. Thickeners are of the peripheral traction type and rakes travel at the rate of one revolution in 37 to 39 min. The entire installation provides 500,000 sq ft of settling area, or approximately 101/2 sq ft per ton of tailing to be thickened daily.

Jan 1, 1957

By Donna lynne Anderson

This report documents the status of a laser-based underground guidance system for tracking and controlling the movements of underground mobile mining equipment. This research is part of a multiple project effort at the U.S. Bureau of Mines to increase mine safety and efficiency by developing technology for computer-assisted mining. Guidance systems, which can track and control the movements of underground mining equipment, are essential during computer-assisted mining operations. A continuous mining machine at the Bureau's surface test facility served as the test-bed for initial development and experimentation of this guidance system. Subsequently, a continuous mining machine in an underground mine served as the platform for in-mine experimentation The first section of this report includes details of the laser sensors, communication network, and computer hardware. The next section includes experimental results, which show the system capable of accurately tracking and controlling the tram maneuvers of a continuous miner underground. The final section discusses conclusions and recommendations.

Jan 1, 1992

By P. Bakke

Following extensive R&D efforts, Hydro Magnesium has launched a new alloy series with remarkable combinations of properties. The AE alloy family is based on additions of aluminium and rare earth elements to control mechanical properties, including elevated temperature creep strength. By combining these alloying elements with manganese additions, high purity alloys with outstanding corrosion performance are defined. A basic philosophy behind the developments has been to simultaneously approach all the critical issues related to developing a commercial material. Apart from the obvious requirements for material properties, the critical issues relate to die casting performance, as well as alloy production, recycling and environmental compatibility. Some of the important elements related to alloy production and recycling are addressed in the present paper.

Jan 1, 2006

By R. J. Mechin

TOP-SLICING was introduced in the Pachuca district in 1917 by T. C. Baker, at that time mine superintendent, of the Santa Gertrudis mine. There then existed 1200 ft. (365.7 m.) below the surface, lying between the fourteenth and eighteenth levels (a vertical distance of 108 meters) a block of ore having a length of 295 ft. (90 m.), and an average width of 82 ft. (25 m.) and dipping at an angle of 65°. This block lay in the hanging wall of the vein and consisted of highly altered and fractured andesite, cut through with mineralized quartz stringers. On the foot-wall side, 26 ft. (8 m.) of old filling, left by former operators, was of payable grade. Stoping therein was first undertaken by the square-set filling system, but because of the extremely heavy hanging wall and loose dry filling in the foot wall, all square setting had to be accompanied by spiling, which made the operation exceedingly slow and costly. A system of mining was sought that would eliminate the difficulties inherent to the square-set system in heavy ground and that at the same time would effect the desired economies in mining. After several years, top-slicing has met all the conditions most satisfactorily, so that when similar conditions presented themselves in El Bordo mine, this method was adopted with necessary modifications. El Bordo mine is operated by the Santa Gertrudis company, and is situated about two miles north of Pachuca. Because of the diversity of the orebodies, a number of different mining methods are in use, among them top-slicing.

Jan 10, 1925

By A. M. A. Mohamed, F. H. Samuel, S. Valtierra, H. W. Doty, A. M. Samuel

"The influence of Fe, Mn, Cu and Mg alloying additions, Sr modification and grain refinement on the microstructure of as-cast and solution heat-treated Al-10.8% Si alloys was investigated using optical microscopy and EPMA techniques. The results showed that the modification effect of Sr diminished with increasing Cu and Mg additions, due to Sr-Cu-Mg interactions. Strontium caused segregation of AlzCu in areas away from eutectic Si regions, and altered the precipitation sequence of the a-Ah5(Fe,Mn)3Siz iron intermetallic from post-dendritic to pre-dendritic, with the phase observed within the a-Al dendrites. Depending upon the alloy Fe and Mn content, a coarser variation (""sludge"") of the a-Fe phase occurred, in the form of polyhedral shaped particles. The AhCu phase dissolved almost completely during solution heat treatment, while Al5Cu2Mg8Si6, sludge, and a-Aln(Fe,Mn)3Siz phases persisted in all alloys, particularly at high Mg and Fe levels. The f3-Al5(Fe,Mn)Si phase dissolved partially in Sr-modified alloys, the dissolution becoming more pronounced after solution heat treatment."

Jan 1, 2006

By F H. S dosSantos, R L. C Santos

The main objective of this work was to develop, at a laboratory scale, a process for treating residues from the settling stage of water treatment so as to remove and recover the aluminium as sulphate. The chemical analysis of residues from different water treatment plants indicated that the aluminium content varied from 15 to 20 per cent w/w. By using the appropriate experimental conditions, it was found to be possible to leach most of the aluminium content. The pH value of the recovered water was suitable for it to be recycled to the water treatment process and the residue appears to be suitable as raw material for bricks. The process developed contributes to the sustainability of the water treatment process.

Jan 1, 2002

Contact Angle Measurements on Lignite Surface

Sep 13, 2010

By D. B. Williams

The end of the war in Europe and the Pacific failed to curb the upward trend of production in Venezuela,- which easily surpassed that of any previous year. The total production for 1945 amounted- to 323,369, 430 bbl., which was 26 per cent over the total for 1944, the previous peak in the history of the oil industry of the country. This increase was caused mainly by the greater demand for petroleum in the last stages of the war; the fact that the danger from enemy submarines had been overcome, which allowed all oil companies to use increased shipping facilities, and the fact that more materials were available for drilling operations. However, the materials supplied were by no means adequate and considerable credit is reflected on the Venezuelan petroleum industry for the increased production obtained by utilizing all available equipment to its fullest extent.

Jan 1, 1946