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By Felipe Krug

A decapagem química, necessária para a remoção de óxidos e hidróxidos da superfície dos arames na galvanização contínua a fogo, emprega uma solução a base de ácido clorídrico que necessita constante monitoramento. O controle da temperatura e a concentração, são imprescindíveis para obtenção de custos competitivos, qualidade de produtos e manutenção da segurança operacional. Este trabalho realizou uma crítica, nas práticas e controles já implantados, identificando desperdícios e oportunidades e fazendo um re-alinhamento do processo alterandose parâmetros e rotinas de forma a obter o menor custo, mantidas qualidade e segurança operacional.

Aug 16, 2017

By Edward Griffith

The anthracite industry, which produces about 50 million net tons of coal annually, has been talked of as being able to last for another century; but if the water record of the past century continues into the expected century, this expectation of many years production still to come out of the remaining reserves will not be attained. The industry will be a submerged one in fact as well as in name. A recorded forecast of what has since occurred appears on page 34 of the Mine Inspectors' reports of 1897: It should also be noticed that bodies of water had accumulated in parts of abandoned mines before duplicate surveys of the same were required by law; and as a result we have today to contend with bodies of water, the exact location and position of which are not correctly known. Since that date, 47 years ago, the implications of the foregoing comment have grown enormously. This is shown in Fig. I and in the following table showing flooded and partially flooded areas that have come into existence since the early 1930's in the northern anthracite field: Number of Year Flooded Areas 1932...................... 2 1933...................... 3 1934..................... 3 1935...................... 5 1936...................... 7 1937...................... 9 1938.................... 11 1939...................... 11 1940...................... 11 1941...................... 14 1942...................... 14 1944...................... 26 Similar conditions exist in other fields in the anthracite region. In the period between 1923 and 1940, abandonment of collieries in the southern field resulted in the flooding of approximately 60 sq. miles (30 per cent) of the field. The ahandonment of collieries in this field has imposed additional expense for pumping on the collieries still operating. This condition will be aggravated by the extension of developments and cause suspension of operations if economic conditions do not justify the assumption of additional pumping costs. During the years, the region's rainfall has not altered, but the quantity going inside the mines through breakages in the surface, brought about by extraction of the coal, has increased materially, as indicated by the ratio of tons of water pumped to tons of coal produced underground for one of the large companies in the northern anthracite field: Year Ratio 1920................. 8.4:1 1925.................. 10.6:I I930.................. II.4:I 1935................. 26.2:1 1940.................. 32.7: I 1942.................. 30.3:I The data in Table I shows the total amount of water pumped and its ratio to underground production for one of the large companies in the southern anthracite field, and shows a rapidly growing serious situation. Rainfall quickly affects the workings in all the fields. In mine inspection district 7 of the southern field the rainfall in 1935 was 92,083,000,000 gal. The total water pumped was 36,274,000,000 gal. (39.4 per cent of the rainfall). The operating mines

Jan 1, 1947

By Edward Griffith

The anthracite industry, which produces about 50 million net tons of coal annually, has been talked of as being able to last for another century; but if the water record of the past century continues into the expected century, this expectation of many years production still to come out of the remaining reserves will not be attained. The industry will be a submerged one in fact as well as in name. A recorded forecast of what has since occurred appears on page 34 of the Mine Inspectors' reports of 1897: It should also be noticed that bodies of water had accumulated in parts of abandoned mines before duplicate surveys of the same were required by law; and as a result we have today to contend with bodies of water, the exact location and position of which are not correctly known. Since that date, 47 years ago, the implications of the foregoing comment have grown enormously. This is shown in Fig. I and in the following table showing flooded and partially flooded areas that have come into existence since the early 1930's in the northern anthracite field: Number of Year Flooded Areas 1932...................... 2 1933...................... 3 1934..................... 3 1935...................... 5 1936...................... 7 1937...................... 9 1938.................... 11 1939...................... 11 1940...................... 11 1941...................... 14 1942...................... 14 1944...................... 26 Similar conditions exist in other fields in the anthracite region. In the period between 1923 and 1940, abandonment of collieries in the southern field resulted in the flooding of approximately 60 sq. miles (30 per cent) of the field. The ahandonment of collieries in this field has imposed additional expense for pumping on the collieries still operating. This condition will be aggravated by the extension of developments and cause suspension of operations if economic conditions do not justify the assumption of additional pumping costs. During the years, the region's rainfall has not altered, but the quantity going inside the mines through breakages in the surface, brought about by extraction of the coal, has increased materially, as indicated by the ratio of tons of water pumped to tons of coal produced underground for one of the large companies in the northern anthracite field: Year Ratio 1920................. 8.4:1 1925.................. 10.6:I I930.................. II.4:I 1935................. 26.2:1 1940.................. 32.7: I 1942.................. 30.3:I The data in Table I shows the total amount of water pumped and its ratio to underground production for one of the large companies in the southern anthracite field, and shows a rapidly growing serious situation. Rainfall quickly affects the workings in all the fields. In mine inspection district 7 of the southern field the rainfall in 1935 was 92,083,000,000 gal. The total water pumped was 36,274,000,000 gal. (39.4 per cent of the rainfall). The operating mines

Jan 1, 1947

By T. Sreenivas

This paper describes results of laboratory studies on recovery of dissolved uranium values from alkaline leach slurries of a medium-grade uranium ore from Gogi (Karnataka, India) using the resin-in-pulp (RIP) process. Besides anionic carbonate complex of uranium, the other major ionic constituents of the leach solution are CO32-, HCO3-, SO42- and MoO42-. The total dissolved solutes (TDS) are about 45 g/L. Various commercially available strong bases anionic resin-in-pulp (RIP) grade resins ? both macroporous and gel type, were studied with respect to their loading capacity. Parametric variation studies were then carried out with the short-listed resins. Results of the semi-continuous counter-current extraction and elution tests indicated extraction efficiency of about 98% and practically complete elution of the loaded uranium values with NaCl eluant using a gel type polystyrene based resin grafted with quaternary ammonium ion. Keywords: uranium, hydrometallurgy, ion exchange, resin-in-pulp

Sep 1, 2012

Pillar design is the first line of defense against rock falls—the greatest single safety hazard faced by underground coal miners in the United States and abroad. To help advance the state of the art in this fundamental mining science, the National Institute for Occupational Safety and Health organized the Second International Workshop on Coal Pillar Mechanics and Design. The workshop was held in Vail, CO, on June 6,1999, in association with the 37th U.S. Rock Mechanics Symposium. The proceedings include 15 papers from leading ground control specialists in the United States, Canada, Australia, the United Kingdom, and the Republic of South Africa. The papers address the entire range of issues associated with coal pillars and have a decidedly practical flavor. Topics include numerical modeling, empirical design formulas based on case histories, field measurements, and post failure mechanics.

Jan 5, 1999

By Nancy E. Wilk

In 2015, more than 1.2 million deaths annually were estimated to be caused by occupational risks (WHO, 2018). In 2021, this estimate increased with the publishing of the World Health Organization (WHO) and the International Labour Office (ILO) Joint Estimates of the Work-related Burden of Disease and Injury based on data from 2000 to 2016 (WHO/ILO, 2021). These global estimates reported that each year 1.9 million people die from exposure to occupational risk factors, 81% of these fatalities resulting from non-communicable, occupational diseases. WHO/ILO notes that the health-related risk factors with the largest number of attributable deaths were exposures to long working hours followed by workplace exposures to particulate matter, gases, and fumes. The health outcome with the greatest work-related burden of deaths was chronic obstructive pulmonary disease, followed by stroke and ischaemic heart disease. In considering the 2021 data published by WHO/ILO, it is likely that the estimates are low and underestimate the true burden of occupational disease and injury. In support of that position, more recently the ILO estimated that “2.3 million women and men around the world succumb to work-related accidents or diseases every year; this corresponds to over 6000 deaths every single day” (ILO, 2022).

Jan 1, 2023

By Robert Alfred

This paper is one of a aeries being published by the Federal Bureau of Mines on methods and practices used in mining and preparing crushed stone for market. Performance, in terms of units of work or tons produced per machine and per operator man-hour, is given whenever that information can be obtained. Direct operating costs are useful for comparing different methods and are included if available. In addition to descriptions of equipment and methods used the Bureau considered it desirable to discuss the engineering reasons for the choices that have been made, This paper is particularly concerned with the operation of the Liberty quarry and plant of the Campbell Limestone Co, The plant is in Pickens County, adjacent to the main line of the Southern Railway, and is about 18 miles west of Greenville, S, C. Access also is available by United States Highway No, 123, The company's main offices are at Knoxville, Tenn.

Jan 1, 1958

By Joseph T. Singwald

INTRODUCTION THE purpose of this chapter is to present the diagnostic features (geologic, mineralogic, chemical, and physical) of the principal types of hypogene ore deposits recognized in current genetic classifications, and to classify the ore deposits of the western United States into those types. The genetic divisions used and the criteria determining them are essentially those followed by Lindgren in his Mineral Deposits. Deviations from Lindgren represent either changed conceptions since 1928 (the date of the third edition of Mineral Deposits) due to advance in knowledge or the inevitable differences of opinion between experts in active fields of investigation. Though nineteen economic geologists have been given free hand in presenting their particular topics, there are no fundamental departures in the chapter from the principles set forth by Lindgren. It would be entirely beyond the capacity of a single chapter to give a comprehensive geologic description of all the ore deposits of the western United States. Descriptions of individual deposits have been restricted to those features that are of most diagnostic genetic value. All of the more important deposits receive that much attention. Deposits of lesser economic importance and those inadequately known geologically are treated more briefly or merely cited under what seems to be their proper genetic assignment. The geographic limits of the descriptive matter are the Black Hills and the United States between the Rocky Mountains and the pacific Coast. Capacity of the chapter has made it necessary to impose these geographic limits.

Jan 1, 1933

By R. H. Lien

The Bureau of Mines investigated a roast-leach process for recovering a marketable lithium product from a montmorillonite-type clay deposit located on the Nevada-Oregon border. The clay sample treated in the investigation contained 0.6 wt pct Li. The lithium recovery process consisted of several unit operations. The lithium silicate compounds in the clay were converted to Li2SO4 by roasting a pelletized mixture of clay, limestone, and gypsum at 900° C in a direct-gas-fired rotary roaster. Water--leaching the calcine at 40 pct solids extracted the Li2SO4. Lithium recovery from the leach solution involved concentrating the solution by evaporation, adding Na2CO3 to the concentrated solution to precipitate Li2CO3 , and filtering the slurry to obtain the product. The product filtrate was recycled to the evaporator following a crystallization step. About 80 pct of the lithium in the clay was recovered as 99-pct-pure Li2CO3. Process operating costs were estimated at $2.12/lb Li2CO3 produced; the current Li2CO3 selling price is $1.48/lb. Raw materials. accounted for 30 pct of the total operating cost.

Jan 1, 1985

By A. Roy MacLean

This paper outlines the changes in modern-day coal mining that have been brought about by the increased cost of labour and the use of new and highly efficient equipment. In the latter category are mentioned the ramp-plate, the Bretby cable carrier, armoured face conveyors and the shearer-loader. Greater productivity and increased safety are emphasized.

Jan 1, 1969

By D. Preece

The mining and oil industry employs techniques such as geologic mapping, core drilling and electromagnetic and potential field techniques to explore for new deposits. Since new discoveries of major near-surface ore bodies are becoming progressively rare and since traditional exploration methods are unable to resolve ore bodies deeper than about 500m, high-resolution seismic reflection techniques show great potential for exploration to much greater depths down to almost 3km.

Jan 1, 2011

By Andres M. Baquerizo, Jeremiah J. Filjones, Nicholas Feldt

The Estates at Acqualina located in Sunny Isles Beach, FL, is comprised of two, ocean-front, 50-story, luxury towers with podiums and villas. With city regulations now requesting that above-grade floors be limited to commercial or residential units, parking facilities for the tower structures were situated within two levels of underground basement parking. However, ensuring dry excavation through south Florida’s highly pervious limestone, immediately adjacent to the beach where the groundwater table is very shallow, can be extremely challenging and costly for developers. In recent years, significant advances have been made to overcome this challenge with the innovative use of deep soil mixing to create a “dry hole”, assisting in the construction of foundations and underground usable space for parking, storage, etc. The “dry hole” system includes a soil mix bottom seal, with soil mix secant pile walls in combination with auger cast deep foundation elements to support the future structure. This approach enables groundwater control to greater depths than can be achieved by conventional sheetpiling and dewatering. For the Estates at Acqualina, a successful turnkey, design-build joint venture between two foundation and geotechnical contractors resulted in a dry excavation to 34 ft (10.4 m) below grade and to a record- breaking auger cast pile depth of 182.3ft (55.6 m), all within an aggressive 26-week schedule to deliver the “dry hole” excavation for the first tower. This presentation will discuss the logistics, quality control, design, and safety for the different techniques involved. INTRODUCTION AND BACKGROUND The Estates of Acqualina is a pair of 50-story luxury towers located on Sunny Isles Beach in Florida with a two-level underground basement for parking. The project’s location just steps away from the Atlantic Ocean, geology, and high-water table created a challenging project. The owner, Trump Group, contracted the joint venture of HJ Foundation and Hayward Baker (HJ/HB) to design-assist-build a system to control the groundwater, allowing the 2-story underground parking structure to be constructed. In order to accomplish this task, the JV utilized an installation technique known as deep soil mixing. This technique mixes the in situ material with a cement slurry to create a very impermeable material called “soilcrete”.

Jan 1, 2019

By D. C. Fuller

"CoaLiquid, Inc. (CLI) has been in the coal-oil-mixture (COM) business for over five years. The initial pilot processing facility was replaced by a 2000 barrel per day commercial production facility in August 1979. For over two years CLI has been expanding its efforts and conducting large-scale production and combustion demonstrations successfully in many locations across the United States. To facilitate the marketing effort, CLI has recently constructed a special trailer containing all equipment needed for a temporary COM retrofit.CoaLiquid has conducted commercial-scale combustion demonstrations in the following types of combustion units: kilns, calciners, industrial boilers, blast furnaces and driers.IntroductionCoaLiquid, Inc. officially dedicated its plant on August 31, 1979, at a ceremony presided over by the then Governor of Kentucky, The Honorable Julian Carroll. The dedication marked the culmination of over three years of research and development work and marked the beginning of a new era of coal-oil-mixtures as a commercial commodity in the marketplace. As the first such plant in the United States, it set the tone for construction to follow.CLI was originally owned and managed by a group of entrepreneurs from Kentucky who had developed the process and constructed the plant on purely private investment and conventional financing. Beginning in late 1976, with a pilot-scale operation, also located in Shelbyville, Kentucky (near Louisville), CLI began producing a stable mixture of 50070 coal, 30% to 40% oil and 10% to 20% water by weight. The technology employed was developed by Eric C. Cottell of Long Island, New York and is covered by U.S. Letters Patent No. 3,941,552. Since the pilot plant operation, CoaLiquid has made many refinements to its process and in fact has added new technology to its portfolio of patents and patents pending. Further refinements to the product now produce a stable mixture of 50% coal, 40% No.6 fuel oil and 10% water by weight."

Jan 1, 1985

By A. Gauthier, J .. E. Muir, M. Cormier

Falconbridge's Lac Shortt gold deposit is located in Gand Township, some 25 km north-east of Desmaraisville, The deposit was outlined in i980 by a drilling program me conducted by Falconbridge Ltd. in a joint venture with Corporation Falconbridge Copper after three years of systematic exploration by Falconbridge Ltd. in the Desmaraisville area. The gold bearing structure had previously been drilled by three other exploration companies. As based on an underground development programme conducted by Corporation Falconbridge Copper, the "in-si tu" mineral inventory to a depth of 500 metres at a cut-off grade of 3.0 g/t is estimated at 1 937 605 tonnes at a grade of 6.4 g/t (uncut) and 6.0 g/t (cut). Regionally, the stratigraphy consists of thick sequences of volcanic and volcanosedimentary rocks intruded by numerous and voluminous mafic (gabbro), felsic (granodiorite, syenite) and anorthositic intrusions. Structurally, at least two fold sets and one major fault system (E-NE) are present. Minor fault systems oriented E-NE and N-NW also occur. Mine stratigraphy can be divided into 1) - the hangingwall; 2) - ore zone; 3) - footwall. Hanging wall rocks include: a) green lapilli and blocky tuff b) transition zone c) green mica crystal tuff and d) red dolomitic tuff. Ore zone rocks include: a) bleached mafic tuff b) barren carbonates, c) pyritic dolomitic tuff (?) and d) brick-red syenite. Footwall rocks include: a) magnetic lava (so-called diorite), b) mafic lapilli and blocky tuff and c) alkali basalt, Native gold is the only gold mineral so far identified and it occurs both as free grains in gangue and as micro-inclusions in pyrite. Two geochemical groups were identified in the main rock units: 1) Alkali-rich rocks cons is ting of the ore zone and foot wall rocks and 2) Subalkaline group consisting of the hanging wall rocks. Ore analysis also shows Ba, Sr, W, Zr, REE and F enrichment in the ore zone. Footwall rocks are enriched in Na20. Present geological and geochemical data do not permit a clear interpretation of the formation for the Lac Shortt gold deposit but suggest it is a volcanic-hosted stratabound type. The bulk of the mineralization is associated with an exhalative phase following alkalic, carbonic, hydrothermal activity and part of the mineralization is associated with a late intrusive phase.

Jan 1, 1984

By Graham W. Marks, Clyde A. Bridger

"INTRODUCTION An electrolytic process for the preparation of metallic cobalt has been developed recently in the Bureau of Mines Experimental Station at Boulder City, Nev. Chemical analysis shows this cobalt to contain impurities in small percentages, chief of which is nickel. It is desirable to be able to determine these impurities spectrographically. This report is concerned with a procedure for the spectrochemical determination of nickel in cobalt.Previous spectrographic work on cobalt was done by Breckpot and Mevis,/ who used the method of homologous pairs of lines. However, it was felt that a more detailed investigation was needed, employing the method of internal standards.ACKNOWLEDGMENTWe are indebted to B. G. Knickerbockor and his staff at the Boulder City, Nev., station of the Federal Bureau of Mines for their cooperation, and particularly to Richard W. Lewis and Robert G. Sanderson, who prepared nickel-free electrolytic cobalt for us."

Feb 1, 1948

By Karl C. Dean

The Bureau of Mines stabilized 10 acres of windblown copper mill tailings at McGill, Nev., by a combination chemical-vegetative procedure. Legumes, winter wheat, wheat-grasses, and wild rye were seeded, and the area was subsequently sprayed with a resinous adhesive chemical to stabilize the sands until the vegetation could grow. During the year since treatment, the area has been well stabilized against wind erosion. The established vegetation appears to be capable of self-perpetuation and renewal without irrigation. The cost of stabilizing the area was $135.50 per acre.

Jan 1, 1969

By Frank J. Cservenyak

Curtailment of bauxite importation by enemy activities during World War II focused attention on the necessity of developing domestic deposits of aluminous materials. Large quantities of aluminum ores such as kaolin, siliceous bauxites, high-iron bauxites, anorthosite, and diaspore clays are available but not readily amenable to Bayer processing because of excessive impurities. The Bayer process, which is the only commercial method in use in the United States for producing metallurgical-grade alumina, requires a high Al2O3 bauxite relatively low in SiO2 and Fe2O3. The Bureau of Mines was charged by Congress to investigate processes for the production of alumina from these low-grade ores. One part of the program was an investigation, in the laboratory and pilot plant, of the recovery of alumina by the lime-soda sinter process. Ores comprising kaolin, diasporic clays, anorthosite, and siliceous bauxites have been investigated and studied in the laboratory and pilot plant, and a series 'of reports covering these investigations has been prepared.

Jan 1, 1948

By Md. Nafiul Haque, Murad Y. Abu-Farsakh, Chris Nickel

"This paper presents the results from a pile load testing program for a bridge construction project in Louisiana. The testing includes two 54-inch open-ended spun cast concrete cylinder piles (OECP), one 30-inch open-ended steel pile (OESP), and two (30-inch and 16-inch) square prestressed concrete (PSC) piles driven at two locations with very similar soil conditions. All the test piles were instrumented with vibrating wire strain gauges to measure the load distribution along the length of the test piles and the skin friction and the end bearing were derived from strain gauge measurements. High strain dynamic load tests (HSDLT) were performed on all test piles at different times after pile installations to quantify the amount of setup with time. Static load tests were also performed on the PSC and open-ended steel piles. Due to expected large pile capacities, the statnamic test method was used on the two open-ended cylinder piles. The pile capacities of these piles were evaluated using various CPT methods (such as Schmertmann, De Ruiter and Beringen, LCPC, COFS methods). The result showed that all the methods can estimate the skin friction with good accuracy; but not the end-bearing capacity. Setup was observed for all the piles, which was mainly attributed to increase in skin frictions. The setup rate parameters “A” [The “A” parameter is defined as the rate of increase of pile capacity ratio (Rt/Rto) per log cycle of elapsed time] were back-calculated for all the test piles and the values were between 0.31 and 0.41.INTRODUCTIONDue to greater efficiency (capacity to weight ratio) of the pipe piles, open-ended piles are a viable option to solid piles. However, the behavior of open-ended piles is more complicated compared to the close-ended piles owing to possible formation of “soil plug” inside the open-ended pile. Many researchers have analyzed the behavior of both types of piles for different purposes; however, very few studies in the literature offer the side-by-side comparison of the close-ended and open-ended piles."

Jan 1, 2017

By Craig M. Jensen

A laboratory assessment of prompt and delayed neutron activation analysis with 252Cf and 14MeV neutron sources, for use as an in-situ method of determining low-level copper concentration has been performed. A simulated borehole using porphyry ore was constructed and varying copper concentrations were simulated using copper rods. Prompt neutron activation analysis experiments were consistant with earlier work and do not appear to be feasible fur copper concentration of 1.5% or less. Delayed neutron activation analysis experiments indicate that copper ore concentrations of less than 0.1% are detectable using either the 511-KeV gamma-ray of copper-64 or the 1039-KeV gamma-ray of copper-66, with high resolution detectors such as Ge (Li) or intrinsic germanium.

Jan 1, 1977

By J Holdsworth, L Sutton, A Lavrinec, D Ilic

Air quality is a big topic of discussion in regional mining communities as well as urban environments situated close to port terminals handling bulk solids. Community perception of poor air quality can significantly affect the reputation of the mining operation and handling facilities. Dust monitoring for regulatory compliance relies on using a handful of accurate but very expensive sensors, usually situated at the boundary, relatively far from the activities that generate the airborne dust. These reference monitors measure dust leaving the site but dust mitigation and management on-site largely relies on operator judgement. At a fraction of the cost, small wireless solar powered units can be used to supplement reference monitors in real-time. Due to their compact nature, portability and low price, these units can be implemented on a mass scale to increase spatial resolution of dust measurements and, more importantly, in much closer proximity to both the dust generating activity and the sources of dust. This can provide valuable insights into the origins and timing of dust generation thus producing datadriven decision-making while minimising subjectivity. Similarly, light detection and ranging (LiDAR) is another supplemental technology that can be used to increase the spatial resolution of dust measurements in near real-time, however, the cost of commercial systems even exceeds that of regulatory monitors. LiDAR also presents difficulties in quantifying dust plume concentrations. This study presents learnings of implementing both technologies for dust emissions management. Several low-cost sensor units and a fast-scanning custom-built 3D LiDAR system operating at a range of 1.5 km with a resolution of 1.5 m were deployed on a surface mine to monitor dust emissions from different activities. The project explores the use of real-time sensor data to quantify LiDAR measurements in parallel with integration into mine planning. The approach can assist in prioritising dust mitigation activities thereby reducing instances of emissions exceedance and minimising water use through databased and targeted application. Demonstrated is an opportunity for a step-change in industry best practice as well as commercialisation and operationalisation of the method across different industries, including future mineral extraction.

Sep 18, 2023