Search Documents

By Michael E. Henderson

The U.S. Bureau of Mines (BOM) constructed the Hydraulic Transport Research Facility (HTRF) to investigate the hydraulic parameters relating to the transport of coarse coal. To achieve these goals in a timely and efficient manner, the Bureau contracted to Boeing Services International, Inc. (BSI) the responsibility of operating the HTRF and providing technical support. This data report is a summary of the testing and data results for the period from 16 September to 1 November 1983. The testing covered herein is for coarse 2-in by a (minus 50 mm) Pittsburgh Seam coal in a 12-in (3 00 mm) pipeline, at velocities ranging from 5 to 18 ft/s (1.5 to 5.5 m/s) and at concentrations ranging from 15 to 55 pct.

Jan 1, 1985

By Oscar Ccaccya Anca

Se viene realizando monitoreo de condición a las Zarandas Vibratoria en Chancado Secundario y Terciario, para lo cual se aplica diferentes técnicas de Análisis, entre las cuales está la técnica de Vibración, que, gracias a una serie de configuración respectiva y filtros del valor adquirido, puede apreciarse el deterioro progresivo para su pronta intervención.

Sep 1, 2017

By JAMES GAYLE

(Presented at the Washington meeting, May 3, 1905, and simultaneously sent to the Iron and Steel Institute, for presentation at the meeting of that Society in London, May 11, 1905.) IT is to be regretted that the data respecting the use of dry-air blast, which was presented to the Iron and Steel Institute at its meeting in the United States, in October, 1904, should. have been restricted to the period from August 25th to September 9th inclusive, and from September 17th to 30th inclusive. In order to present the paper at all it was found necessary to limit the record of operations to the period above stated. In the discussion of the paper it would appear from the conclusions of some participating therein, that they have been placed at some disadvantage in considering the economies obtained through the use of dry-air blast, by reason of the data covering such a short period. It is the purpose of this communication to present in detail the record of operations of the Isabella Furnaces from November, 1904, to March, 1905, inclusive, as shown by the furnace-records. The month of October, 1904, is not included, as the furnace using dry-air blast was stopped several times for repairs, and while the record was a very good one considering these interruptions, yet it was not a continuous one. The record for Furnace No. 1 using dry-air blast, and the comparison with Furnace No. 3 using natural air for the month of November, 1904, is set forth in Table I. By a reference to my former paper it will be noted that the month of November is the beginning in this country of the winter period, when the atmosphere decreases rapidly in humidity. The month of October being the transition month in the autumn and April in the spring, and furnaces using natural air approach more closely, from November on, to the conditions obtained by the use of dry-air blast. The data given in

Jul 1, 1905

By R. M. de Carvalho

Empirical and phenomenological models of SAG and AG mills have dominated the scene for the last few decades, being used nearly every time a mill is scale-up or an attempt is made to improve its performance. However, in spite of their success, these models fail to describe the details of both the grinding environment and the breakage mechanisms. The result is a generally good track record, with a few ? but very important ? instances when these models fall short in their predictions, which can be very costly. Further, nearly all of these models require detailed calibration to industrial and pilot plant data, being costly in their application, although still with limited predictive capabilities. Recognizing these challenges, a new model framework has been proposed which overcomes the limitations of currently used models by coupling the microscale population balance model, the discrete element model and functions that describe internal classification at the mill grate. This model framework has already been applied to describe breakage in ball mills, with showing very promising results. However, in the case of SAG and AG mills a much greater level of complexity is involved in the model, given the interaction between the mechanical environment that is formed totally or, in part, by the ore itself, and the breakage response in the mill. The paper describes the model framework, demonstrating how it can address appropriately effects such as mill speed, mill filling and size distribution, on the response from the mill. Some of the advantages of the model are related to its intrinsic multi-component and dynamic nature, which allows simulating appropriately mixtures of ores of different competences in a transient manner.

Jan 1, 2012

By Richard A. Thomas, Liming Yuan, Lihong Zhou, James H. Rowland

Hydrogen (H2) gas released during battery charging can result in cross-interference for carbon monoxide (CO) sensors used for early fire detection and compromise the integrity of the mine atmospheric monitoring system (AMS). In this study, a series of laboratory-scale and full-scale experiments were conducted to evaluate the responses of different CO sensors to H2 gas. In the laboratory-scale experiments, constant H2 concentrations in the airflow, from 100 to 500 ppm, pass through sensors. While in the full-scale experiments, increasing H2 concentrations generated as a byproduct from charging the batteries at the battery charging station rise to the sensors under different ventilation scenarios. The H2 concentrations at the CO sensor location were measured using H2 sensors and were correlated with the CO sensor response. The effects of ventilation and sensor location on the CO sensors responses were also analyzed. The results of this study can help mining companies to select appropriate CO sensors and improve the deployment of these sensors to ensure the safeguard of underground miners.

CARL A. WENDELL, New York, N. Y. (written discussion*) .-I have never seen in print anything that even remotely has approached this article in clearness and important conclusions in conjunction with work done on the sink-and-float test. I have had many hundreds of these tests made and on different specific gravity solutions and the resultant product analyzed, but I have never grasped nor been able to show what this article sets forth. This article brings out one factor very clearly to my mind; what is to take the place of the solutions of different specific gravities used to obtain the laboratory results, when it comes to washing on a large scale, since water has one constant weight only? The answer is, sizing of coal. And as we know the importance of size versus specific gravity of the material to be washed, perhaps defined (practical) lines can ultimately be gotten up so that the sizing, if any, may be determined at the same time as the laboratory work on the coal is being done. G. R. DELAMATER, ? Steelton, Pa. (written discussion?).-The authors' deductions are well founded and although they disclaim any wide experience in commercial coal washing, practically all of the data presented are applicable to coals of all parts of this country. The paper clearly sets forth the great necessity of careful preliminary investiga-tion of each contemplated washery undertaking and contains the follow-ing very true statements. "It is not safe to assume that any coal which can he successfully washed on coarse coal jigs can be cleaned more com-pletely by washing at a finer size on tables," and "The effect of finer crushing upon the completeness with which impurities may be separated from coal depends upon two opposing tendencies. First, that the more finely a raw coal is crushed, the more completely will the particles of impurities be detached from the particles of clean coal. Second, the finer a coal is crushed the more difficult it becomes to separate the pieces of clean refuse from the pieces of clean coal."

Jan 12, 1919

"INTRODUCTION Twin Metals Minnesota (TMM) (operating as a joint venture between Duluth Metals and Antofagasta PLC) assumed control of the property in 2010. Amec became involved with the project in 2011 and in 2012 incorporated additional drilling in order to update historic resource estimates. The Maturi geological model and resource estimate was updated in 2014 to incorporate additional information obtained during 2013 and 2014 drill campaigns. In 2017, Amec was purchased by the Wood Group and is now known as Wood. Geology The Twin Metals Minnesota (TMM) Maturi, Maturi Southwest, Birch Lake, and Spruce Road properties are located in northeastern Minnesota (Figure 1). This talk discussed the Maturi deposit only, although all four deposits share similarities. The following geology is summarized from Peterson and Severson (2002).Maturi lies within the Superior Province of the Canadian Shield which is exposed in central and northeastern Minnesota and extends northward into Ontario. In eastern Minnesota, the Midcontinent Rift System developed during crustal scale extension in the Mesoproterozoic Era. The rift system is traceable, as exposures of mantle-derived tholeiitic to subalkaline mafic lava flows, intrusives, and rift-filling fluvial sedimentary rocks, and in the subsurface as a gravity anomaly (high), from the eastern end of Lake Superior, arcing west across the lake basin, and extending south-southwest to northeastern Kansas. Intrusion of the Duluth Complex, circa 1,108 - 1,099 Ma, was related to rifting and is co-genetic with the North Shore Volcanic Group mafic volcanic rocks that form the hanging wall of the Duluth Complex to the east. Cu-Ni-precious metals (PM) mineralization including Pt, Pd, Au and Ag within the Duluth Complex is hosted by mafic to ultramafic intrusive rocks that are part of the overall intrusive complex. The Duluth Complex is defined as a more or less continuous mass of mafic to felsic plutonic rocks that extends northeastward for more than 170 miles (275 km) in an arcuate fashion from Duluth nearly to Grand Portage in Minnesota. It is bounded by a footwall of Paleoproterozoic sedimentary rocks and Archean granite-greenstone terranes (Peterson and Severson, 2002), and a hanging wall largely of comagmatic anorthosite, rift related flood basalts, and hypabyssal intrusions of the Beaver Bay Complex. Mineralization is hosted in the basal mineralized zone (BMZ) of the South Kawishiwi Intrusion (SKI). The SKI magmas intruded sub-horizontally between hangingwall Anorthositic Series (AN) rocks and footwall granitic rocks of the Neoarchean Giants Range batholith (GRB). The Maturi local geology and the deposit footprint (shaded orange) is shown in Figure 2."

Jan 1, 2018

By Deepesh Yadav, B. S. Choudhary

Underwater drilling and blasting is conducted for deepening of sea channels for port berths, lake or reservoirs for water supply etc. so that rock dredging becomes easier. During this process there are several associated unwanted effects having potential to cause damage to surrounding structures and the environment, flora and fauna. Though all these ill effects can’t be completely eliminated but adopting controlled blasting techniques can minimize these to tolerable levels. It is recognized that ground vibrations resulting from rock blasting below water near dam may endanger the safety of earthen dams. Therefore, controlled blasting technique was used to ensure the safety of dam and its efficacy was established by monitoring of blast vibrations. The usage of small quantity of explosives confined in blast holes, non-electrical delay detonators and initiating each hole with a separate delay helped to minimize the ground vibration effects on surrounding structures.

Jan 1, 2018

By Víctor T. Mejía Campos

El presente texto describe el proceso de remolienda efectuado en el circuito de flotación de bulk en la concentradora Casapalca. Dicho estudio se basa en dos proyectos anteriores, donde se buscó mejorar la molienda inicial con la instalación de un molino de bolas Marcy - 64-1/2 y el uso cuatro ciclones tipo Krebs de lú11 (3 en trabajo permanente y uno de repuesto) y un clasificador tipo Dorr Duplex de 71 x 28-1/2' de 19 rastrilladas por minuto. Dado el éxito obtenido en el primer proyecto, se prosiguió con el segundo. Finalmente, el 6 de octubre entró en operación normal el nuevo circuito de remolienda de las partículas gruesas en el circuito de flotación de bulk donse se comparó los promedios de los resultados metalúrgicos obtenidos en el año 1960, contra los resultados obtenidos en el año 1962 y se evidenció que este proceso mejoró la recuperación, produciendo más toneladas adicionales de concentrados.

Aug 20, 1963

By W. W. Adams

"Accidents at coal mines in the United States in September 1926 resulted in the loss of 170 lives, according to information furnished to the Bureau of Mines, Department of Commerce, by State mine inspectors. Of this number 125 occurred at bituminous mines and 45 in the anthracite field. As the bituminous output of coal for September was 48,976,000 tons, and the production of anthracite was 8,444,000 tons, the fatalities reported represented a death rate of 2.55 per million tons for bituminous mines and 5.33 for anthracite mines. The industry as a whole showed a fatality rate of 2.6 per million tons of coal produced in September 1925 the rate for bituminous coal mines was 3.29; the anthracite mines were idle in September last year due to a strike.During the first nine months of the present year 1,759 men have been killed by accidents at the coal mines throughout the United States, resulting in a death rate, per million tons of coal produced, of 3.76 as compared with 3.95 for the same period in 1925. Reports for bituminous mines alone showed a nine-month fatality rate of 3.53 which was about the same as the corresponding rate from January to September in 1925. The anthracite rate for the present year, however, shows a decrease of about 17 per cent; that is, the rate has declined from 6.36 to 5.28.Records covering the first nine months of 1926 show that 12 ""major"" disasters, that is, disasters in which five or more men were killed at one time, have resulted in the loss of 271 lives as against 10 disasters and 199 deaths in the corresponding months in 1925. The fatality rates for these disaster: alone were 0.579 and 0.465, respectively. One major explosion occurred at Tahona, Oklahoma, on September 3, 1926, in which 16 men lost their lives.An analysis of the principal causes of the 1,759 fatalities for the first nine months of the present year shows a reduction in the death rate as a whole and for falls of roof and coal and for explosives, but an increase in haulage, gas and dust explosions, and electricity. The comparative rates for these accidents were:"

Oct 1, 1926

Hidden under picturesque Bemic Lake, in Canada's eastern Manitoba, lies a highly fractionated pegmatite orebody, hosting a unique assemblage of minerals. Accidentally discovered in 1929, the orebody had a brief history as a tin producer, but it is now mined by Tantalum Mining Corporation of Canada, Ltd. (TANCO), for its cesium, lithium, rubidium and tantalum bearing minerals. The mine also has potential for mbidium-feldspar, amblygonite, gallium rich mica, and quartz production. This paper describes the geology of the orebody, and its mining and processing. Selective, concurrent, mining and milling of the various products necessitates a high degree of planning and control, and these aspects are also discussed. The introduction of Quality Control and SPC are discussed, for such are the keys to excellence.

Jan 1, 1989

By K. E. Kolm, W. H. Langer

Developing natural aggregate resources (sand, gravel, and stone) creates environmental impacts. A systems analysis method has been designed to characterize the components of the environmental system, identify potential impacts to those systems, and evaluate the extent of those impacts. The step-wise method consists of problem definition, data collection, preliminary conceptualization and characterization, additional data collection, data analysis, and refinement. The method requires analyzes of various systems making up the environment, including land surface, geomorphic, subsurface, and groundwater systems. After system characterization is complete, the method focuses on identifying and evaluating potential environmental impacts to determine acceptable mining strategies.

Jan 1, 2001

By H. 0. HOFMAN AND W. MOSTOWITSCH

I. INTRODUCTION. THE mineral gypsum, CaSO, + 2 H2O, has been used for many years as a sulphurizing and basic flux in several smelting¬operations. Thus, in smelting oxide nickel-ore in the blast furnace, it is commonly added to the charge to furnish the sulphur necessary for collecting the metal in a matte, and a base for slagging the siliceous gangue. In the concentration of lead-copper matte in the reverberatory furnace it has been used for years at Freiberg, Saxony1 for a similar purpose, and for producing at the same time a copper-matte with less than 0.15 per cent. Fe. The latest use gypsum has been put to is in the blast-roasting process of Carmichael-Bradford.2 The term "blast-roasting," given by A. S. Dwight3 to the Dwight-Lloyd method of roasting and agglomerating ,I is a happy generic term which covers the ground better than the " lime-roasting" of Ingalls' or the " pot-roasting " of Austin,6 in that it leaves the operation independent of the character of the flux and the form of apparatus, and retains the characteristic feature of this class of processes-namely, that of using forced draft. In the Carmichael-Bradford process the dehydrated material, mixed with galena-concentrate, acts as a diluent and a flux. The process differs in this from the Huntington-Heberlein7 and the Savelsberg8 processes, in both of which limestone is used.

Jan 1, 1909

By F. Tanaka

Copper losses to discard slag have long impacted on the profitability of copper smelters. Businesses based on the treatment of secondary materials have also revealed that copper losses are indices of precious-metals losses. Many custom smelters are thus required to obtain more reliable controls for reducing copper losses than ever before. Mitsubishi Materials Corp. has cooperated with academic research institutes in conducting research projects on the pyrometallurgical fundamentals of copper smelting systems, including mutual evaluation of magnetite behavior between synthetic and industrial slags. The state-of-the-art pyrometallurgy has subsequently been introduced to Naoshima smelter for controlling the Mitsubishi process. The revised controls function successfully and the operational results demonstrate that avoiding the discharge of solid magnetite from the S-furnace is quite effective to reduce copper losses. Magnetite behavior has been controlled over the Mitsubishi process so as to reduce copper losses while satisfying the needs of recycling businesses growing in Japan. In-situ estimation of magnetite behavior using the absorbed heat from the melts to cooling water will also be discussed.

Jan 1, 2007

By Thomas E. P. Wechsler

The limiting factor for most pyro-metallurgical processes in secondary cop- per melting is the time required to heat and melt the product. American Combustion's proprietary PYRETRON variable £uel/air/oxygen combustion system improves the throughput of existing scrap melting and heating furnaces for copper and copper alloy production by increasing the rate of heat transfer from the flame to the product. The increased productivity and energy savings obtained from this technology can result in sizable reductions in operating costs for smelting operations.

Jan 1, 1991

Bailey, Lewis Newton, Master Engineer, Senior Grade, 4th Regiment, U. S. Engineers, Headquarters Company, died of pneumonia at Camp Merritt, N. J., on April 30, 1918. Baird, Louis, Lieut., Royal Field Artillery, British Army, died on the battlefield in 1915. Ballamy, John H., Capt., 103c1 Engineers, killed in action near Fismes, Aug. 9, 1918. Bowles, Martin F., 2d Lieut., Co. B, 355th Infantry, killed in action, Sept. 3, 1918. Burt, Andrew, died in active service, 1916. Cobeldick, William Morley, Royal Engineers, died from gas poisoning on Oct. 7, 1915. Dougall, Ralph,. 4th University Co., Princess Patricia Regiment, killed in action early in the war. Evans, Alfred Winter, Lieut.-Col., New Zealand Rifle Brigade, D. S. 0., D. C. M., killed in action on Oct. 12, 1917. Gordy, Sheppard B., died in service, Oct. 9, 1918. Gorman, Thomas C., Lieut., Canadian Engineers, killed in France, Mar. 18, 1918. Hague, William, 1st Lieut., Engineer Officers' Reserve Corps, died in active service, Jan. 1, 1918.

Jan 1, 1919

By T. L. Barone, J. R. Patts, L. D. Patts, S. J. Janisko

"Controlling float coal dust in underground coal mines before dispersal into the general airstream can reduce the risk of mine explosions while potentially achieving a more effective and efficient use of rock dust. A prototype flooded-bed scrubber was evaluated for float coal dust control in the return of a continuous miner section. The scrubber was installed inline between the face ventilation tubing and an exhausting auxiliary fan. Airborne and deposited dust mass measurements were collected over three days at set distances from the fan exhaust to assess changes in float coal dust levels in the return due to operation of the scrubber. Mass-based measurements were collected on a per-cut basis and normalized on the basis of per ton mined by the continuous miner. The results show that average float coal dust levels measured under baseline conditions were reduced by more than 90 percent when operating the scrubber. IntroductionAirborne coal dust is a byproduct of coal production, and engineering controls exist to deal with both the respirable dust health hazard as well as the float dust explosion safety hazard. Float coal dust, smaller than 75 µm (0.003 in.) in size, can deposit throughout mine entries and propagate explosions that had been initially fueled by methane gas. The inertization of float coal dust with rock dust helps prevent a potential secondary float coal dust explosion, but a preferable course of action is to significantly reduce the hazard by removing float coal dust from the airstream before it has the opportunity to deposit on the mine’s surfaces.Since 1970, disasters due to explosions in underground coal mines have caused 201 deaths in the U.S. mining industry, including 29 deaths in a single mine explosion in 2010 (Wade, 2010; U.S. Mine Safety and Health Administration, 2015). The U.S. National Institute for Occupational Safety and Health (NIOSH) had initiated a fiveyear research project that aims to investigate methods and technologies to reduce the potential for secondary coal dust explosions by the purposeful capture and/or suppression of float coal dust prior to its deposition on the mine roof, rib and floor (NIOSH, 2013). The project aims to evaluate the efficiency of methods to reduce longwall and belt airway float dust in the general airstream as well as methods to capture it at or near the source. Prioritization is given to longwall sections given the amount of coal produced relative to continuous miner sections, but the research is open to technologies that may be adapted from one method of mining to another."

Dec 1, 2016

By P. W. Allen

Here are the facts and the figures on how Tahawus cut costs and improved safety in solving their secondary breakage problem - A dropball crane entirely eliminated secondary blasting.

Jan 4, 1953

By Bhavani Kedika, Venkatagiri Noole, Krishna Thotla, Krishna Reddy Chepyala

Cationic lipids are attractive candidates for transgene delivery and expression and are safer alternatives to viral delivery vehicles. Here, we report the design, synthesis, characterization and transgene expression efficacies of a series of chrysin derived cationic lipids. A series of ten lipids of chrysin was synthesized by treating the 7-hydroxy group with dibromoalkane and further substitution of the bromo derivative with alkyl amines. The synthesized lipids were characterized spectroscopically. Parallel screening of the synthesized lipids for in vitro plasmid delivery expressing luciferase led to identification of several leads that demonstrated higher transgene expression when compared to the standard. Transgene expression efficacy was dependent on the chain length of the lipid. The influence of the various physicochemical properties on transgene expression efficacies was investigated. This study indicates that lipids derived from chrysin results in high levels of transgene expression and may be attractive for gene therapy applications.

Mar 1, 2017

By J. -M. Lalancette, D. Lemieux, C. Chouinard

"A gold bearing concentrate containing 107 g/T of gold, 9.3% copper and 706 ppm of mercury was processed at the demonstration scale for the extraction of gold and copper using a cyanide free process. The concentrate was generated through flotation to upgrade the gold and copper grade, but also showed contamination with mercury. This concentrate was submitted to the DST process demonstration plant. The concentrate was first oxidized using a fluidized bed to produce a calcine. The mercury was volatilized during the oxidation stage with an efficiency higher than 98%. The mercury was condensed and removed from the sulfuric acid using a thiosulphate process. Copper was extracted from the calcine as copper sulphate using diluted sulfuric acid. The solid remaining after acid leaching was submitted to the DST chlorination process for gold extraction. Under optimized conditions, a gold extraction of 97.3% was achieved in the chlorination reactor. Gold was recovered from the pregnant brine by precipitation on silica using a DST proprietary process.INTRODUCTION Dundee Sustainable Technologies Inc. (DST) offers proprietary metallurgical processes for the treatment of material from the mining industry. DST processes enable the extraction of precious metals and for the removal and stabilization of contaminants, such as arsenic, from ores and concentrates. DST provides environmentally-friendly, viable and efficient processes, capable of handling complex and refractory ores which cannot be processed with conventional approaches due to metallurgical issues or environmental considerations. Several mining jurisdictions around the world have banned or restricted the use of cyanide. DST has developed a closed loop chlorination process as an alternative to the conventional cyanidation process for the extraction of precious metals from minerals. The tailings from the process are inert from toxic substances such as cyanide and organic compounds, are sulphide depleted which means they do not generate acid, and thus, meet and/or exceed environmental norms. The process has demonstrated excellent gold recoveries within a fraction of the time needed for cyanidation to obtain similar results. Moreover, the closed loop process does not generate any liquid effluent and does not consume much water: it only requires a water make-up to compensate for moisture leaving with the tailings and by-products, and seawater may be used. The improved environmental footprint of the DST process has been certified by the Environment Technology Validation program (ETV) which provides an independent evaluation of the performance claims of innovative technologies."

Jan 1, 2017