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By Sergey Gudkov, Yuri Yemelianov, Stanislav Balikov, Andrey Boldyrev, Andrey Bogorodsky

"The results of POX of refractory gold-bearing concentrates using halide-ion as a lixiviant for precious metals and activated carbon as an adsorbent are given. It was found that gold did not recover to the solution when halide was added during POX. Silver partially dissolved in the solution. When halide-based reagents and activated carbon were added during POX, gold dissolved and loaded onto the activated carbon. The degree of sulfides oxidation was 99.3-99.6%. The recovery of gold onto granulated carbon was 94.7-94.8% when using chlorine-bearing lixiviants: NaCL, CaCL and carnalite and 98-99% when using KJ and KBr. This treatment process of refractory gold-bearing concentrates combines sulfide oxidation, dissolution and adsorption of precious metals. The results of the metals recovery achieved using this process can be compared with the recovery during POX-cyanidation. In this case, sodium cyanide was not used. This allows the reduction of capital and operational costs due to the absence of cyanidation, CIL and detoxification of leaching tailings circuits."

Jan 1, 2014

By Izabela Diniz Duarte

Perdas térmicas decorrem do armazenamento do aço líquido em panelas. O controle da temperatura do aço líquido é condição essencial para se obter um produto final de alto nível de qualidade. Este trabalho buscou avaliar a transferência de calor a partir do aço para o refratário da panela e para a camada de escória, utilizando um modelo numérico (Computational Fluid Dynamics). As perdas de calor dão origem a correntes de convecção dentro do banho e a consequência típica desse fenômeno é a estratificação térmica. Foi avaliada a influência de parâmetros tais como espessura da camada de escória, tipo de revestimento refratário e a temperatura de encharque. As perdas térmicas para o refratário lateral e do fundo da panela se mostraram maiores que as perdas térmicas para a camada de escória. Nas condições estudadas a espessura de camada de escória não apresenta influência significativa sobre as perdas, ao contrário do tipo de refratário e temperatura de encharque.

Aug 16, 2017

By William O. Vanderburg

This report3/ gives the reconnaissance of a reconnaissance of the mining districts in Churchill County, Nev., made in the fall of 1938 and spring of 1938 All of the mining districts in the county were visited, but no attempt has been made to include all the mines and prospects within the area; inclusion or omission of a property in this paper has no bearing on its merits, The report gives the situation of the various districts, mineral production, and ownership of properties; describes the ore deposit, mines, and prospects; contains information on past and current activity; and includes other data likely to be useful to those interested in the development of our mineral resources. The various district, were named when they were organized for purposes of record and regulation. When established, the districts embraced large areas n without well- defined borders, so that the names have little geographical significance.

Jan 1, 1940

By W. C. Meyer

In an effort to conserve and extend oil resources, the use of powdered coal-in-oil mixtures (COM) as an alternate fuel in oil-fired boilers is receiving increasing attention. For the approach to be successful, some degree of stability of the suspension against settling is needed. The variety of means available to achieve stability of this nonaqueous slurry is reviewed along with some of the physical and chemical concepts which underlie each method.

Jan 1, 1983

By J. Richard Maier

Short-range mine planning (less than five years) previously was accomplished using contour and isopac maps, pencil and paper, an abacus, and our lucky quarter. Through the use of both micros and mainframe time sharing, Glenrock Coal Company (GCC) has been able to virtually put the old equipment away (except the problem solving quarter). In the process, GCC has saved many man-days and eliminated the more tedious parts of mine planning, such as picking elevations off a map with an engineer's scale and repetitive calculations. These savings have allowed GCC to do a more extensive job of mine planning as well as offer more alternatives, making GCC better prepared for possible economic changes. Mine planning, simply, involves looking at what has been done and deciding what needs to be done using various constraints. The application of this concept is not as easy as it sounds. The need for experience and insight cannot be replaced by a machine, but machines can supplement a person's ability by doing the bookkeeping and the repetitive work. Through the application of computers and their accessories, GCC has brought mine planning to a more modernized state. The following paper will detail the development and use of one system as used at GCC. Please note: In the figures and tables following, some of the data has been altered to protect confidential information used in mine planning.

Jan 1, 1983

By Paúl A. Mulcey

El presente texto revela un informe realizado por el Banco Minero del Perú, donde se investigan las posibles aplicaciones domésticas para la antracita peruana, como las vías adecuadas a la preparación de un programa de estudios en la utilización de combustibles. Entre las aplicaciones industriales de este mineral están las fábricas de cemento, las refinerías de azúcar, las fábricas de vidrio, refractarios, ladrillos, cerámica y fundiciones. De las aplicaciones proyectadas tenemos las de gas de síntesis, plantas de energía y las plantas de laminación. En cuanto los estudios en combustión y aplicaciones, están lo de briqueteo y peletización; los aglutinantes de briquetas, secado y reccocción; y finalmente dentro de los de combustión, está el combustible para la exportación.

Jul 20, 1956

By I. Nishkov, L. Alexandrova

The kinetics of froth flotation and the three-phase contact (TPC) parameters are studied at temperatures varying from 20°C to 40°C. The material floated consists of glass spheres and a quartz particles with various diameters. Dodecylamine hydrocloride (DDAHCI) is used as a collector. The equilibrium three-phase contact angle is measured with a microscope technique using the modified Mingins-Scheludko method. Using a Wilhelmy method, the temperature effect on the surface tension of the DDAHCI solution is determined. The formation of the thin film on a polished plate of vitreous silica and the expansion of TPC is monitored by means of a metallographic microscope and recorded on a attached camera at different temperatures. The experimental data show an intensification of the flotation kinetics at 30 and 40°C in the case of small particles. Such an intensification is not observed with the larger particles. The cause for intensification of the flotation kinetics is sought for in the dependence of the TPC rate of expansion and induction time on temperature.

Jan 1, 1995

By Fordyce Coburn

RICHARD ore mine of the Colorado Fuel & Iron Corp. is an underground magnetite operation located in northern New Jersey approximately four miles northeast of the town of Dover, and 40 miles west of New York City. The mine is situated on the southeastern flank of one of the many gneissic ridges having a northeast-southwest trend

Jan 11, 1953

By G. R. O?Neil

The justification for a "ligand- selective' approach to fine mineral beneficiation via flocculation is established initially. Special emphasis is placed upon the need to identify non-selective, interfering and complicating adsorption effects. Specific strategies directed towards the design and synthesis of complementary selective flocculants are detailed using a number of different polymers and chelating agents as examples. In this regard, the affinity of polymer-bound ligands for metallic cations, ligand concentration, possible modes of attachment, the application of spaced-out ligands and other considerations in the preparation of selective flocculants are highlighted.

Jan 1, 1983

By Jon J. Kellar

The adsorption of oleate at the surface of a fluorite single-crystal internal reflection element has been investigated using Fourier transform infra-red/internal reflection spectroscopy (FTIR/IRS). The application of this innovative experimental technique has added a new dimension to the investigation and understanding of collector adsorption phenomena. It is now possible, for the first time, to measure in-situ and in real time the adsorption density and bonding nature of collector species adsorbed at mineral surfaces. In this regard, oleate adsorption densities were calculated from spectral data, and the equilibrium adsorption isotherms were found to agree quite well with other adsorption isotherms reported in the literature. At low equilibrium oleate concentrations(<10-5 M), monolayer-type cover-age was observed in the chemisorbed region. It was found that in this region the adsorption density increases with an increase in temperature, which sup-ports experimental results from previous ex-situ FTIR studies and thermochemical studies in which it was shown that the chemisorption reaction was endothermic. At higher equilibrium oleate concentrations (>10-5 M), the adsorption density increases dramatically at the point of surface precipitation. The oleate adsorbed in the chemisorbed region has a distinctly different spectrum than the oleate adsorbed in the surface precipitation region of the adsorption isotherm. In the chemisorbed region, the oleate appears to be mono-coordinated at the fluorite surface.

Jan 1, 1989

By W. R. Bendy

GRINDING is a large and costly part of Portland cement manufacture. Prior to clinkering in the rotary kiln, raw materials are ground to a fineness of 80 to 90 pct passing 200 mesh. Then, after burning and cooling, the resulting clinker is ground to about 92 pct passing 325 mesh. In the cement industry the most favored method of grinding has always been by impact and attrition of a ball charge in a rotating mill. Other types of mills, in which materials are ground between die rings and rollers, or between die rings and large balls, are sometimes used for single-stage grinding and often for preliminary grinding followed by grinding in ball-type mills. Their efficiency is usually high, but maintenance and repair costs are high also, and the ball-type mill continues to be the most widely used.

Jan 10, 1957

By J. G. Pippenger

Rio Tinto Coal Australia (RTCA) developed the Meandu Mine in Queensland, Australia in 1983 to supply thermal coal to the adjacent and newly constructed Tarong Power Station (TPS). In designing the mine, RTCA selected Meandu?s best economic reserves for a 27-year life based on station owner Tarong Energy Corp.?s (TECs) estimated life for TPS. That 27-year plan changed dramatically in the early 2000s when TEC approved life extensions to TPS?s four existing units plus construction of a fifth unit. After reviewing Meandu?s remaining reserves, RTCA decided the nearby Kunioon reserve offered the more economic option for maintaining deliveries beyond 2010. Those plans changed again in 2007 when TEC chose to purchase the Meandu Mine and nearby reserves. TEC then selected Thiess Pty Ltd. (Thiess) to continue operating Meandu until the new mine at Kunioon could be developed. After assuming operation of the mine in 2008, Thiess began a review of Meandu?s remaining reserves and found considerable coal available with economic potential. Working jointly with TEC, Thiess performed several analyses on Meandu and subsequently the Kunioon coal reserves. The results changed TEC?s decision from expediting Kunioon?s construction to instead continuing Meandu?s operation for up to 15 additional years.

Jan 1, 2011

This publication summarizes, for potential contractors and all other interested parties, the research and development of in-house and contract projects programmed by the Bureau of Mines for fiscal year 1983 (October 1, 1982-September 30, 1983) under its Health and Safety Technology program. The objective of these projects is to provide an ordered and sequenced series of advance toward the Bureau&apos;s overall goal of providing the systems technology required to create a more healthful and safer working environment for the Nation&apos;s mining and minerals processing workers.

Jan 1, 1982

By D. Pienaar, B. McFadzean, T. Jordaan

"Dithiophosphate (DTP) collectors have the lowest affinity for sulfide mineral surfaces compared to other common sulfide mineral collectors, such as xanthates and dithiocarbamates. In some cases it has been found that DTP does not adsorb onto the mineral surface at all and yet increases in recoveries and grades are noticed with the addition of DTP. Many studies have investigated the interactive effects of collector mixtures. However, there have been relatively few studies on the interactive effects between frother molecules and collectors. This study investigates the interactions between different types of frothers and sodium diethyl dithiophosphate.The study found that there were large increases in pyrite and galena microflotation recoveries at both pH4 and pH9 when DTP was mixed with small amounts of frother at a constant bubble size, showing that these increases were neither mineral-specific nor pH-specific. The same effect was not present when xanthate was used as a collector. The increases in recovery when using the DTP-frother mixture were similar irrespective of the type of alcohol or polypropylene glycol frother that was used. In an attempt to distinguish the mechanism of enhanced flotation recovery, various supplementary experiments were performed. It was found through adsorption experiments that no DTP was adsorbing on to the mineral surface. Therefore, interactions at the air-water interface were performed. Surface tension and critical coalescence concentration tests showed that, while DTP is a weak surfactant at the air-water interface, it does not have a synergistic effect in the presence of frother. DTP-frother mixtures do, however, show interactions in the froth phase, indicating an interaction in the thin films. It is proposed that there is a DTP-frother interaction on the bubble surface that enhances the rate of film thinning at the 3-phase bubble-particle contact."

Jan 1, 2018

By B. C. Alberts

Planning the use of South Africa&apos;s energy resources, especially coal, is of the utmost importance. The State and the mining industry require reliable official estimates of the economically mineable coal reserves for planning purposes. An overview of al the previous reserve estimates is given, with specific attention to the two most recent estimates-those of Petrick and De Jager. The differences between these two estimates are highlighted. The following important aspects are discussed: . the need to update the information regarding South Africa&apos;s mineable coal reserves, . the necessity of understanding and agreement between the coal-mining industry and the State department responsible for updating the coal-reserve data, and . the importance of the specific assumptions used in the updating of the data. A downward adjustment of mineable reserve figures is proposed, and the factors that influence the meaningful exploitation of the coal reserves are discussed. A recommendation is made as to how the Waterberg coal reserve should be exploited, and it is concluded that the Soutpansberg Coalfield cannot be exploited economically in the foreseeable future. An evaluation of the status of the coal-export trade is made and compared with the assumptions and targets set at the start of the coal-exportation scheme. The comparison shows the extent to which the exploitation of the coal reserves is being negatively influenced by the current market situation. Recommendations are made regarding planning for the coal-export market, and the aspects that have to be taken into account to keep South Africa in the export market are identified. Reference is made to the fact that the present unrestrained wage and salary adjustments, which show a total disregard of South Africa&apos;s poor productivity record, require serious thought and speedy rectification if the country is to survive in the export market. A salary and wage strategy must be developed to suit the specific needs of the Republic of South Africa.

Jan 1, 1987

By Albert A. Munsch

The Munsch National First-Aid Instructors Association had its inception during the teaching of a Federal Bureau of Mines first-aid instructors&apos; class at McPherson, Kans., under a cooperative plan of first-aid training. Upon completion of- the course on July 1, 1938 members of the class organized the charter chapter of the association under the name of McPherson (Kans.) District Charter Chapter No. 1. On July 1, 1941, 3 years after the founding of the association, there were 15 chapters in the national council -7 in Kansas, 3 in Oklahoma, 2 in Texas, 2 in New Mexico, and 1 in Arkansas. Although the pioneer work of the association was done in the petroleum industry, the plan will be of even greater benefit to a district in which there are various types of plants, mince, and operations of the mineral and allied industries. ACKNOWLEDGMENTS The writer appreciates the cooperation and assistance of the following persons: S. P. Redfearn, safety engineer, Globe Oil & Refining Co. and affiliated companies, Wichita, Kans., and H. (Chief) Moore supervisor of safety meetings, Shell Oil Co., Inc., McPherson, Kans., for their untiring efforts and enthusiasm in organizing an- attending the first class, organizing three other classes, and helping to plan the work of the association

Jan 1, 1942

The definition of sustainable development is often taken from the so-called “Brundtland” report, requiring that activities of the current generation not detract from the potential welfare of future generations. Mining is often held up as unsustainable in this regard, since the extracted resource is non-renewable. Yet Brundtland’s definition of sustainable development also requires that the current generation address the disparity in welfare across the globe, a facet of Brundtland’s report that most have ignored. This paper examines the impact of mining on the welfare of the poor, empirically assessing mining’s contribution to this second facet of sustainable development.

Jan 1, 2004

By Erika Moonin, Jim Nickerson, Claudio Cimiotti, Roberto Bono

"In response to the severe drought on the Colorado River basin and in order to preserve existing water capacity to the Las Vegas Valley, the Southern Nevada Water Authority contracted a new deep-water intake (Intake No. 3) located in Lake Mead. The current project (Contract No. 070F-01-C1) includes 5 km (3 miles) of tunnel with very difficult geological conditions and a 200- m (650-ft) deep shaft and marine works. This paper will present the current status of the design-build contract being constructed by Vegas Tunnel Constructors and the challenges and problems faced and the innovative solutions developed to handle the difficult conditions encountered during tunneling with up to 15 bars of pressure.ProjectbackgroundThe Las Vegas Valley receives the majority of its water from Lake Mead, which is located approximately 30 km (20 miles) east of the Las Vegas, NV metropolitan area. Due to the severe drought that has hit the southwest region of the United States, the water level in Lake Mead has receded from its high water level of 372 m (1,221 ft) above mean sea level (amsl) to a low of 330 m (1,076 ft) amsl in June 2015. Should the lake level continue to fall, at elevation 320 m (1,050 ft) amsl, the current water intakes will not be able to draw enough water to meet the needs of the local area. The risk of losing water capacity has prompted the construction of a new deeper intake. Not only is the new Intake No. 3 situated at a lower elevation in the lake at 262 m (860 ft) amsl, the new Intake No. 3 is also located to draw better quality (Fig. 1).Project challengesThe project has had several difficult challenges to overcome:• The work consisted of a 1.2 kt (1,300 st) structure constructed on a barge and lowered 100 m (330 ft) into Lake Mead anchored with 9,200 m3 (12,200 cu yd) of tremie concrete.• The drill-and-blast starter tunnel was impacted by three inflow events, resulting in a one-year project delay.• One of the main challenges was selecting the tunnel boring machine (TBM) and excavating the tunnel with expected hydraulic head pressure of as much as 17 bar (16 bar was the highest pressure recorded during the drive), crossing faulted areas, low rock cover and the risk of tunnel instability due to direct connection with the lake.• Extensive pre-excavation grouting with a constant head pressure ranging from 12 bar to 15 bar.• Structural repair of the cutterhead in difficult hydrogeological conditions [water inflow of approx. 800 m3/hr (4,000 gpm)].• Complete repair of the cascade sealing system for the main bearing and two replacements of the pinion bearings.• The TBM approach to the intake structure."

Jan 1, 2015

By H. H. Alexander

In the early part of the last century textile fabric was used for the filtration of products of combustion and lampblack was obtained by passing smoke through a series of canvas bags. Natural draft was used to draw and force the smoke through the bags. About 1850 bag filtration was used for collecting zinc oxide. Around 1876 it was introduced for collecting the fume from lead-ore hearth smelting in Missouri. Shortly afterward it was used, first at Portland, Me., and later at Canon City, Colo., for the collection and production of zinc-lead pigment in treating mixed zinc-lead sulphides. In 1890 the Globe Smelting & Refining Co., at Denver, Colo., installed a bag house containing 1,458 bags for the recovery of fume from silver-lead blast furnaces. This installation was too small to handle all of the gases and was increased to approximately 2,300 bags. In 1900 the number of bags was again increased, making a total of approximately 2,800. The usual difficulties incident to new installations were encountered, but they were gradually overcome and the bag house became accepted as standard practice for this class of smelting, As all of the bag houses built since have followed the general lines of the Globe installation, a short description may be of interest. The general construction of the Globe bag house is shown in Figs. 1, 2, and 3. The building is 149 ft. 8 in. long by 67 ft. 4 in. wide and 40 ft. 2 in. high from the basement floor to the eaves of the roof, having brick walls 26 in. thick from the foundation up to the thimble floor, from there an 18-in. wall for 16 ft. and a 13-in. wall from this point to the top, a distance of 14 ft. 2 in. Additional stiffening is given to the walls above the basement by pilasters located every 16 ft. The end-wall construction is similar to that of the side walls with the exception of the spacing of the pilasters, which is somewhat greater. The roof is made of corrugated iron laid on 1-in. boards and supported by a timber frame work spaced 16 ft. apart resting on the basement partition walls. On top is a louver running the

Jan 1, 1915

By J. B. Zadra

Tungsten, a comparatively new metal, is one of the important strategic war materials. In peacetime, tungsten is widely used as a filament in elec¬tric lamps and electronic tubes and is a vital constituent of some of the most important industrial alloys. High-speed tool steel containing tungsten and stellite alloys containing cobalt, chromium, and tungsten are extremely hard and resistant to corrosion. These alloys and the tungsten carbides are unequaled as cutting tools and in other wear-resistant applications. They play a prominent role in the present era of mass production. Alloys containing tungsten resist oxidation at high temperatures and have been key alloys in the development of modern aircraft. The adaptability of tungsten to new uses is expanding, particularly in the high-temperature range. Domestic production of tungsten has come from a large number of deposits in 17 of the 49 States; but, of the total domestic output from 1900 to 1956, more than 80 percent was produced from mines in North Carolina, California, Colorado, and Nevada. The average tenor of the mined ore was less than 1 percent tungsten trioxide (W03).

Jan 1, 1959