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By Frank G. Breyer

THE .following developments in the zinc field during 1935 are listed in the order of their importance. Each will he amplified in later paragraphs. In the field o f Metallic Zinc: (1) Construction of further continuous vertical retort smelting capacity in the United States and Germany. (2) Expansion of fractional distillation capacity in the United States. (3) Great expansion in the zinc-base die-casting industry in the United States and abroad. (4) Wide acceptance of heavy galvanizing by the steel industry. (5) Construction of the first commercial wire electroplating plant for putting on heavy coats of pure zinc. (6) Firm establishment and appreciable expansion of the practice of using zinc dust as a reducing agent in the organic chemical industry.

Jan 1, 1936

By Cabrera M. Manuel C

A fines de 1980, la empresa Minero Perú construyó una operación piloto de monitores y planta de lavado con una capacidad de 1,500 m3/día, incrementando la producción de oro a un 80%. En este sentido, el presente texto señala la producción de oro de esta minera peruana, utilizando dichas herramientas mencionadas. Para ello, se describe la geología, minado, características del monitor seleccionado, características de la bomba de alta presión, metalurgia y las plantas de lavado.

Oct 14, 1980

By Roy Peratrovich

An innovative cost-saving design for a 1,100 ft bulkhead on the Tanana River at Nenana in central Alaska won Alaska Construction & Oil magazine's Construction Achievement Award. The designers utilized materials available nearby at low cost. They planned sheet pile enclosures, self-anchored back into shore without cell closures. They made it practical for inexperienced local workers to do the building. And they completed the project on time and below a reduced budget.

Jan 1, 1985

By M. Steyn

[Zr(C9H6NO)4]?(HCON(CH3)2)?(H2O), where (C9H6NO) = 8-hydroxy quinoline (oxH), was synthesized and characterized. This tetrakis-coordinated zirconium complex crystallized in the triclinic crystal system (Pi, Z=2) along with water and N,N?-dimethylformamide(DMF) solvate in the asymmetric unit. The metal atom is surrounded by four N,O-donating bidentate ox-ligands that are arranged around the metal centre to give a square antiprismatic coordination polyhedron with a small distortion towards a dodecahedral geometry. Crystal packing is stabilized by intermolecular interactions of adjacent oxine ring systems in neighbouring molecules, as well as hydrogen bonding of the aqua and DMF solvate molecules, linking the molecular entities into a supramolecular three-dimensional network.

Jan 1, 2013

By C. Babcock

When a flat-lying mineral deposit such as a coal seam is mined, some coal is left to separate the roof and floor so that miners and machines can safely mine the seam. The mineral left is in the form of mine pillars. If too much is taken, support problems and unsafe working conditions result. If too little is taken, the mining operation will be unable to compete economically with other mines. Therefore, one must select pillars of the optimal size to maximize mining recovery and minimize risk to miners and equipment. Later, if the pillar support is no longer needed and the surface can be allowed to subside the thickness of the coal seam, then the pillar support can be removed to increase mining recovery, and initial pillar size is not as critical. Only a small part of the information available on pillar design can be presented here. The purpose of this report is to summarize some of the work done by the U.S. Bureau of Mines and others on pillar design, which is reported in the literature from 1833 to the present, and present rock mechanics test results that aid in understanding mine pillar behavior. The variable names used are those of the authors cited. This results in multiple use of some variable names.

Jan 1, 1994

By John G. Henning

The Hoyle Pond underground mine is located in the Porcupine Gold Camp, 18 km east of downtown Timmins. Since the initiation of production in 1985, the operation has produced in excess of 1.9 million ounces of gold at a grade of 15 grams per tonne. Currently, Hoyle Pond ranks 8th in total ounce production for all past and present producing mines in the camp, with the highest head grade of any of the significant past, or present producing mines in Timmins. Cut and fill, shrinkage, longhole and panel mining methods are employed to excavate the narrow gold bearing structures. Using illustrative examples, this paper provides an overview of factors, such as geologic setting, rock mechanics challenges and mine infrastructure, which influence mine design at Hoyle Pond.

Oct 1, 2004

By A. N. Baldwin

This report documents the work performed under Bureau of Mines Contract J0265029 to study and develop two innovative mining systems: ? An underground auger capable of augering into the right and left ribs without repositioning the machine ? A conventional mining system employing recently developed innovative machinery. The report is separated into two volumes to document the two studies separately. Volume I describes work performed and the recommended concept for a bidirectional auger. Volume II describes the studies of mining equipment performance and mining plans developed to determine a conventional mining plan offering improved productivity.

Jan 1, 1977

By Thomas. L. O.

Apart from a few sketches and incomplete maps, mainly topographical, and one or two detailed maps of placer-creeks, there is little information on the topography and geology of most of the country adjacent to the sections of the Alaska Highway in the Liard River area, particularly that part east of Kechika river. In 1943, the Geological Survey of Canada made a recon-naissance from Fort Nelson clown the river of that name to the Liard, thence up the latter to Hell Gate, and also up Beaver river for a distance of fifty miles. The whole of the area covered was found to be underlain by sedimentary rocks, not a single igneous dyke being seen. The British Columbia Department of Mines began reconnaissances near the highway both in and north of the drainage basin of Prophet and Muskwa rivers with a view to finding structures favourable for the accumulation of oil. In Liard River valley near the mouth of Smith river and at intervals from there clown to Devil' s Portage occur warm springs whose character and origin are not definitely' known, since they have not been investigated (21, p. 38A). Similar springs are said to occur at several localities over a broad belt extending from Muskwa river across the Liard to the Nahanni River country (26, p. 11). On Liard river below the mouth of Dease river, stratified sands, gravels, and clays of Pleistocene (?) age are constantly met with and in one or two places are underlain by sandy clays. The distribution of the latter, however, is very limited in the section cut by the river west of the Rocky mountains. The only range of these mountains that reaches the Liard is the high limestone ridge which approaches the mouth of Vents river from the southeast and then almost vanishes a few miles to the northwest of it (27, pp. 43-45). In general, the ranges of the Rockies in the area under consideration have been but little explored, but they are undoubtedly very largely sedimentary and, with the exception of some volcanics and intrusives on their western flanks, are probably almost entirely so. Unlike the high, deeply incised ranges in southern British Columbia, they dwindle in elevation north of Terminus mountain to low-wooded ridges separated by wide swampy valleys, and practically lose their identity between it and the Liard. The foothills, which, along the Liard, have a width of 38 miles (from near the mouth of Trout river to Hell Gate) are composed of a great series of alternating shales and sandstones, with some limestones, all folded closely together, which resemble those found in the foothills farther south (27, pp. 50, 19-20).

Jan 1, 1944

By Joseph M. Kurtak

The Bureau of Mines conducted a four year (1985-1988) mineral assessment of the Juneau Mining District in southeast Alaska as part of its ongoing statewide mining district evaluation program. Following an extensive literature search, the Bureau investigated mines, prospects, and mineral occurrences in the area. This report describes the results of Bureau work in the Eagle River area of the Juneau gold belt; a component of the Juneau Mining District comprising 87,000 acres between the Mendenhall Glacier and Berners Bay. Gold and silver have been the only metals having significant production from the area and occur mainly in quartz stringer and fissure type veins hosted by phyllites, greenschists, greenstones, altered diorite dikes and quartz diorite gneiss. Gold also occurs in several small placer deposits. Approximately 21,100 oz of gold and nearly 9,000 oz of silver were produced over a 60 year period. Currently, the only mining activity consists of some exploration and minor placer gold production. Inferred and indicated lode gold resources having mineral development potential total approximately 796,000 tons with a weighted average grade of 0.22 oz/ton gold.

Jan 1, 2011

By Vincent A. Scovazzo

On March 12, 1994, the 1,100-foot deep 2 Yard South panel of the 1l0 year-old Retsof Mine collapsed. At the time of this occurrence, the Retsof Mine was characterized as the world's largest, most productive salt mine. The collapse produced a seismic event and resulted in a sinkhole and small lake forming on the surface. An existing highway bridge was rendered unusable. Water entered the mine and despite valiant efforts by the miners and the mining company, the entire mine was flooded and lost. John T. Boyd Company (BOYD) studied the incident to evaluate design procedures, and assess the short- and long-term environmental impacts of the collapse. This paper presents our analysis of the cause of the collapse and our review of the rock mechanics design of 2 Yard South panel. Our review is, in part, based on a rock mechanics monitoring program of 2 Yard South. The monitoring program was established by the mining company as the panel was developed and continued even after the panel became unstable.

Jan 1, 1997

By Casey Erickson

Goldstrike Property ??Located in Elko, NV USA?Carlin Trend ??Mining Since 1985 ??27 Million Ounces of Gold Mined ??Production of 400,000 tons/day ??1,600 Employees

May 1, 2011

By Antonio Nieto

According to the analysis of surface powered haulage accidents involving off-highway haul trucks in openpit mining, the U.S. Mine Safety and Health Administration (MSHA), reported 1,300 fatal accidents from 1990 to 2005. Of these, 163 were considered off-highway truck haulage accidents, and at least 23 involved collisions of an off-highway truck with a neighboring vehicle or a worker on foot (Nieto and Dagdelen, 2006). In general, an average of 18 nonfatal accidents and three fatal accidents occurred in openpit mining per year when equipment backed over the edge of an embankment, stockpile or dump point (Fessak, et al., 2003). The specific problems that need to be solved can be determined by carefully studying the accidents involving haulage trucks (Marrara, et al., 2004). Solutions to haulage truck safety must consider the human factors affecting each task even when engineering solutions seem most appropriate. In surface haulage, human performance becomes a critical issue because of the unusual demand the vehicle?s places on their human operators: ? Roadways and working areas change frequently in mining operations. ? The sheer mass of mining equipment such as trucks requires control inputs (e.g., braking) far in advance of the desired action. ? Rough roads, loading and unloading impacts can subject the driver to dangerous shocks and vibration. ? Visibility is sharply curtailed by the bulk of the vehicle generating large blind spots. All of the above issues can be attributed partially to the lack of visibility (Pyles et al., 2003). Driver visibility and communications are key issues to reduce mining truck accidents. Analysis of fatalities and injuries involving mining equipment demonstrates the need to develop new intervention and control strategies to mitigate the risks associated with mining equipment operation. Ongoing development of these and other new strategies is required to achieve a reduction of injury in the mining industry

Jan 2, 2010

By Sean Gallagher

This report was written in an effort to provide better control measures for low back pain (LBP) and low back disability in the mining industry. There are numerous factors associated with development of LBP, many of which can be effectively controlled while some cannot. Better job design is promoted as the best method of reducing cases of LBP and can also reduce the disability (i.e., lost time from work) associated with LBP when it happens. The report draws attention to what is currently known about LBP, what the causes are thought to be, and discusses recent back injury trends in the mining industry. Research describing unique physical demands in mining, such as the capabilities and limitations of working in awkward postures, is also presented. Methods that can be used to prevent initial LBP episodes are provided, including facilities design and layout for materials and supplies, use of mechanical-assist devices, improved design of lifting tasks, and better seat design. Methods of reducing the disability associated with LBP (including workplace design, proactive return-to-work efforts, communication, and management commitment) are also discussed. The report concludes that control of LBP and disability in mining requires a comprehensive approach to limit the repetitive loading that can occur on the low back due to manual materials-handling tasks and exposure to whole-body vibration (WBV). Specific recommendations include the following: ? Successful LBP prevention efforts require a proactive program that has strong management commitment and incorporates employee involvement. ? More efficient supply handling systems and use of mechanical-assist devices can greatly reduce exposure to hazardous lifting tasks. ? Lifting tasks should be designed to minimize low back stress. Tools to evaluate and redesign lifting tasks are presented. ? Improved seat design can reduce exposure to WBV and improve posture, leading to reduced LBP risk. ? The disability associated with LBP can be reduced. Getting the worker back on the job as quickly as possible is in the interest of everyone involved.

Sep 1, 2008

By E. G. Baglin

As part of an effort to decrease U.S. dependence on imports of critical and strategic metals, the Bureau of Mines investigated three leaching methods for extracting the base metals and recovering platinum-group metals (PGM) from matte prepared from Stillwater Complex flotation concentrates. Because of a limited supply of natural material, synthetic matte of composition similar to matte prepared from natural concentrates was used to devise the extraction sequences. The validity of the sequences was verified with matte prepared from Stillwater concentrates. In two-stage matte leaching, first-stage H2S04 leaching extracted 99 pct of the nickel and iron from the matte but negligible amounts of copper and PGM. Second-stage oxidative leaching with Fe2(S04)3 or FeC13 solubilized more than 98 pct of the copper and no precious metals. Sequential leaching, in which acid and oxidizing lixiviants were added sequentially to the matte without an intervening filtration step, extracted 99 pct of the Fe, Ni, and Cu. A roasting-leaching technique, in which the residue from first-stage leaching was roasted between 360° and 500° C before a second leaching with H2S04, solubilized 98 pct of the copper. The three leaching methods yielded high-grade PGM residues containing more than 98 pct of the PGM in the matte.

Jan 1, 1982

By G. O. Oniyide, H. Yilmaz

The South African platinum mines in the Bushveld Complex (BC) have unique features that distinguish them from the gold mines. They have a higher horizontal stress closer to the surface, lower occurrence of seismic activity (caused mainly by pillar failure), and are sited in an area of high geothermal gradient. One of the future challenges of platinum mining is the increasing temperatures as the mining depth increases. High temperatures invariably bring about higher ventilation costs and require different approaches to human factors and ergonomics. Excavation stability would also be another area of concern due to increasing stresses. In this investigation, the effect of temperature on the physical and chemical properties of selected Bushveld rocks (chromitite, pyroxenite, norite, leuconorite, gabbronorite, mottled anorthosite, varitextured anorthosite, granite, and granofels) was studied by means of optical microscopy and scanning electron microscopy using energy-dispersive Xray spectrometry (SEM-EDX). The rock specimens were heated in a temperature-controlled oven a rate of 2°C /min to 50°C, 100°C, and 140°C and kept at temperature for five consecutive days. Samples were allowed to cool to ambient temperature (approximately 20°C) before image capturing. Micrographs of the specimens were taken before and after heat treatment. All the SEM samples were also subjected to heating and cooling on alternate days for ten days in order to observe the effect of repeated heating and cooling on the rocks. The results of the optical microscopy analyses showed minor physical changes in the rocks. The SEM images revealed that cracks initiating at lower temperatures extend with increasing temperature. The chemical analyses showed that the temperature range considered in this research is not high enough to induce changes in the chemical composition of rock samples.

Jan 1, 2016

By Paul M. Price

The Mouat mine, Nye, Mont., was reopened in 1953 by the American Chrome Co. under a Defense Minerals Production Administration contract. Operations were terminated in 1961 after completion of the contract. Mining methods employed during this period are described in detail, and cost data are presented by years for 1953 through 1959. Ultramafic rocks of the Stillwater complex in Montana contain the largest domestic resource of chromite, and the Mouat mine has been the largest producer. Mine reserves were estimated in 1960 to be about 4.4 million tons containing 22.5 percent Cr2O3. The chromite deposits occur as a series of overlapping bands or lenses roughly paralleling the steeply dipping layers of the complex. Only two of the chromite layers have proven to be of economic importance. One layer is 2 to 16 feet wide; the other is 3 to 8 feet wide. Shrinkage stoping was generally used throughout the mine, but various methods of ore breaking, stope drawing, chute construction, etc., were tested to improve output and lower costs. Long-hole stoping proved to have limited use. Breasting down benches, developed outward from the center of the stope with air-leg drills, was satisfactory only in wider stopes. At the close of operations, the company had standardized the use of lightweight stopers to advance a flat back by breaking from a centrally located face. Mining costs were reduced 47 percent during 7 years of operation.

Jan 1, 1963

By Yataro Shimomura

La alza de precios, salarios y las restricciones impuestas por los controles de la contaminación ambiental produjo un aumento en los costos de minado, generando que las operaciones nacionales mineras sean cada más difíciles. Sin embargo, la industria minera logró superarlos, mejorando la tecnología del minado, mecanización y racionalización de sus operaciones. De otro lado, el uso de métodos de minado por cuartos y pilares ha disminuído, mientras que los de corte y relleno y de subniveles se han incrementado. A esto se suma que la utilización de brocas "TC" y del "AN-FO", mejoraron la eficiencia del minado y redujeron los costos. En este sentido, el presente texto señala los últimos avances en tecnología minera a partir de los métodos de extracción, perforación, así como el empleo de relleno de tajeos con relaves de flotación, logrando un desarrollo en la seguridad y eficiencia de la minería subterránea.

Nov 20, 1972

By J F. Seale

The design of the settling pond for the Malvern Hills opencast coal project was based on a primary requirement to control runoff and sediment generated from the immediate 6 ha mine catchment, which included two seepages from old underground workings. The pond has been particularly effective in controlling turbidity in the outflow water, with the consent limit of 50 NTU being met on all but one occasion and normal levels of discharge less than 10 NTU. Water quality testing carried out at the time of consenting indicated that there were no acid-generation issues with the proposed mine site in dominant mudstone strata of the Broken River Formation, and that water from the old mine workings was near-neutral in terms of pH and well-buffered. However, it became apparent over the very dry summer of 2003 - 2004 that slaking of the exposed mudrocks in the mine batters was resulting in significant acidity generation, and outflow pH levels were well below the consent limit of 6.5 during and following periods of rainfall. Although these acidity problems have been remediated in the short-term by the use of lime products, it is clear that a programme of lithotype characterisation for AMD should have been undertaken and this has now been implemented. Design of long-term acid drainage control measures is being carried out, and will probably be based around the use of hydrated lime for pH control with enhancement of natural wetlands.

Jan 1, 2004

By Karsten Zimmermann

Surface deformation monitoring is required all over the mining industry. For example oil and gas companies need this information to support exploration and production activities and to detect impacts from surface subsidence of existing hydrocarbon fields. Also opencast mines require large area information of subsidence due to dewatering of the overburden. Because of this, a lot of surface deformations measurements with GPS or traditional geodetic measurement techniques have been conduced during the last decades. This paper presents the actual capabilities to analyze GPS data using the state of the art Bernese GPS Software for GPS post processing. A new way of monitoring subsidence is a combination of GPS and satellite InSAR data. Considering this it is hoped that a combined strategy will permit receiving overall more information by integrating high point density of InSAR and accuracy of GPS. DMT is one of the leading actors on GPS services especially for monitoring surface movements from underground activities e.g. mining, water pumping or oil and gas exploitation. The paper will discuss preferences and problems of this approach on results of a current project of DMT.

Jan 1, 2008

By A. E. Kasten

The contract objective was to develop and test automatic fire control systems for large surface machinery in surface coal mines. The effort described by the report covers the period from 31 January 1977 to 11 November 1977 and accomplished the following tasks: ? Data accumulation, mainly from visits to the major manufacturers and mine sites. ? Hazard analysis of blast-hole drill, mining shovel, and dragline. ? Recommended design concepts for automatic fire control systems for each of these vehicles. ? Detail system designs for each of these vehicles. ? Procurement of prototype systems for the blast-hole drill and mining shovel. ? Installation of the prototype systems on machines at a surface mine and demonstra¬tion of performance by fire tests on the machines.

Jan 1, 1977