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The SART (sulfidisation, acidification, recycle, and thickening) process is an effective way to separate copper and cyanide from each other in the waste stream of gold processing plants using cyanidation. Factorial experimentation has been conducted to create models of copper recovery, cyanide recovery, acid addition, and oxidation I reduction potential during SART. Economic analysis of the resultant models showed that SART is best operated with a sulfide to copper molar ratio of around 0.56, a pH of 4, and a minimised cyanide to copper molar ratio. The experiments also showed that thickening time may have drastic impacts on SART performance.

Jan 1, 2011

By Edward D. Thimons

Inflatable stoppings are currently marketed for production use, and numerous mining companies have become interested in using such stoppings in rescue and recovery operations. The Bureau of Mines therefore evaluated the concept of using inflatable stoppings in emergency situations. The stoppings tested by the Bureau were 12-foot-diameter spheres inflated with a blower operated by a small battery pack. Experiments were conducted with the stoppings in a full-scale wooden mine model to evaluate their ability to withstand sliding or slipping at various internal and differential pressures, puncture resistance, various inflation techniques; and internal leakage from the stoppings. The stoppings were then installed and tested in the Bureau's Safety Research Coal Mine at Bruceton, Pa., to determine their effectiveness as mine air barriers. Despite some encouraging results obtained with the model and in-mine studies, the stoppings did not perform well in two operating metal mines where they proved difficult to erect and inadequate as air barriers.

Jan 1, 1976

By Dianyin Liang, Hongxiang Ran, Xiaoming Wang, Xiaoou Xia

"This paper presents a new magnetic separator, which can be applied to increase the grade of fine magnetite ore feeding of ball mill. This innovative equipment possesses a rotating magnetic system and has a magnetic field of rapid polarity change which can strengthen the destruction of magnetic agglomerations and the dispersion of minerals to improve the quality of separation. Now this type separators have been successfully applied in several large concentrating plants such as Shuichang Iron Mine under Shouang Mining Company in China. Finally, this paper outlines practical results focused on feed grade and tailing yield, the results are showing that the quality of feeding can be improve tremendously. Hence, a new generator of rotating magnetic field has been paved. INTRODUCTION Jidong region in China is the important origin of iron ore, the characteristics of the iron ore in this region is low grade and complex, the iron mine discharges fine powder tailings reaches tens of millions of tons each year, in the wind action easy to form sand, this poses a threat to the atmosphere environment of Beijing. In order to reduce the mixing of large amount of useless ore and reduce the energy consumption of mill operation, a high efficiency pregrinding equipment is needed. Rotating magnetic field separator (RMS) is an advanced equipment, the main advantage of RMS is the significant reduction in particle entrapment and can easily break magnetic agglomeration. This reduction is so significant that RMS is capable of operating very close to theoritical limit for separator precision and can increace efficiency in selection process.Some expenrimental work on dry rotating magnetic field separation has been carried out in July 1998 in the company Ka Pty Ltd, then in 2008 BGRIMM developed industrial separation XCTG0816 in Shandong province . The wet RMS was researched in1960s in Former Soviet Union and the first industrial equipment was developed by BGRIMM in 1970s,then in 1990s wet RMS was applied in Ansteel group corporation. In 2017,6 units large wet RMS (SXCT1230)which were the largest RMS was applied in Sichuan province. No matter wet RMS and dry RMS, although they are used in differenct applications, they have some common research.in addition ,they all have good use effect."

Jan 1, 2018

By I. D. Shah

The Bureau of Mines investigated the sequence of principal chemical reactions taking place during the roasting of covellite (CuS). Practically all covellite is converted to digenite (Cul.SS) before oxidation to Cu20 begins. Part of the Cu2O is then converted to CuO, which in turn forms CuS04 through CuO?CuS04 as an intermediary. CuS04 and CuO'CuS04 decompose at 600° to 700° C to yield CuO and S03 (g) as final products. An overall mechanism is proposed for chemical reactions occurring at different interfaces of partially oxidized CuS pellets.

Jan 1, 1970

By Douglas E. Wolfe, Jogender Singh, Robert Miller, Dong-Ming Zhu, Jeff Eldridge

This paper discusses microstructural changes produced by two novel approaches using electron beam physical vapor deposition (EB-PVD) in which periodic strain fields/microporosity was incorporated within the large columnar grains of Zr02- 8wt.%Y2O3 (8YSZ). The traditional columnar microstructure of partially stabilized zirconia has been slightly modified to produce a lower thermal conductive thermal barrier coating (TBC) by periodically interrupting the condensing vapor resulting in microstructural modifications with diffuse or sharp interfaces and morphological changes on the sub-micron scale without changing the composition of the TBC. These microstructural modifications resulted in a 20-30% reduction in the thermal conductivity, 28-56% increase in hemispherical reflectance, improved oxidation cyclic life (over 100%), and better strain tolerance as compared to standard ZrO2-8wt.%Y2O3 deposited on platinum-nickel-aluminide and CoNiCrA1Y bond-coated MAR-M-247 test samples. The TBC with tailored microstructures were examined by various techniques including scanning electron microscopy (SEM), x-ray diffraction (XRD), steady-state laser heat flux technique, and hemispherical reflectance.

Jan 1, 2004

By Simon C. Dominy, Alwyn E. Annels, Mark A. Noppé

Abstract - Mineral Resources and their subsequent conversion to Ore Reserves are of key importance to mining companies. Their reliable estimation is critical to both the confidence in a feasibility study, and also to the day-to-day operation of a mine. Together with sampling, assaying, geological and other errors introduced during interpretation and estimation, additional errors are likely to be introduced during the application of technical and economic parameters used for conversion of resources to reserves. There is thus a requirement for high-quality interpretation and estimation to be supported by high-quality data. Any company expecting to make sound investment or operational decisions must base this on both relevant and reliable information. An Ore Reserve statement generally contains a single set of grade and tonnage figures without a discussion of the potential inherent errors in these estimates. Some sensitivity studies may be run, but confidence limits are rarely quoted and, if they are, often do not take into account many of the factors that cause uncertainty in the grade and tonnage estimates. Mineral Resource and Ore Reserve estimates thus carry certain errors leading to uncertainty and risk; some of these are unquantifiable for various reasons, for which the operator should be aware. This paper presents a review of the potential sources of error that might occur during a resource estimation program, which are carried through into the reserve estimate. A number of methods are discussed that allow the estimator to be more transparent about the inherent risks in his/her estimate. Emphasis is placed on data quality, and the requirement for strong quality management to be linked to continuous improvement.

Jan 1, 2002

By J. E. Hamak

This publication contains analyses and related source data for 266 natural gas samples from 20 States and 2 foreign countries. None of the analyses have been previously published in annual reports. All samples were obtained and analyzed as part of the U.S. Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1992

By L. K. Witika, J. H. Masinja

"Investigations of flotation characteristics of Lumwana and Kansanshi ores using formulated frothers were carried out. Of the six frothers tested, two came from the alcohol family, two from the glycol family and last two were formulated products. The initial work involved determining the optimum mesh of grind and frother dosage for Lumwana and Kansanshi ores. Further work involved carrying out surface tension, bubble size and froth stability measurements. Finally, water recovery tests were conducted at Lumwana and Kansanshi mine sites. For froth stability tests, six frothers were tested on a two-phase (water–air) system using the Bikerman column flotation cell, while water recovery tests were conducted using a total of seven frothers, including the standards for each plant. The results of the testwork showed that (i) although a stable froth is essential for optimum recovery of valuable minerals, a higher molecular weight frother, like Dowfroth 250, caused poor selectivity when used on fine ores and (ii) a lower molecular weight frother was suited for Lumwana ore, while a mid to higher molecular weight formulated product was suitable for Kansanshi sulphide ore. INTRODUCTION Investigations of flotation characteristics of Lumwana and Kansanshi ores using formulated frothers were carried out. The initial work of this project involved determining the optimum mesh of grind and frother dosage for Lumwana and Kansanshi ores. Further work involved carrying out surface tension, bubble size and froth stability measurements. Finally, water recovery tests were conducted at Lumwana and Kansanshi mine sites. In order to investigate the gangue entrainment levels in the Lumwana and Kansanshi sulphide ores, two well-known methods (froth stability and water recovery) were used. Firstly, froth stability tests were conducted using six frothers, two from the glycol family (Dowfroth 200 and Dowfroth 250), two from alcohol family (MIBC and pine oil) and other two from the formulated family (Betafroth 20 and Betafroth 245), at the University of Cape Town’s Centre for Mineral Research (CMR) laboratories. Froth formation and stability measurements were conducted using the Bikerman column flotation cell."

Jan 1, 2015

By Saghar Farajzadeh, Fatemeh Kazemi, Ataallah Bahrami

Spirals, the most common equipment for the separation of heavy minerals such as chromite, are greatly affected by size distribution and the liberation degree (hence the specific gravity and size) of the feed particles. In this study, the efficiency of spirals in separation of low-grade chromite particles has been investigated by studying the distribution of grade, size distribution and liberation degree of feed, concentrate, and tailings of spiral. For this purpose, mass balance constraints were applied to the spiral-containing chromite processing circuit. Afterwards, the grade variations and size distributions have been investigated. According to the results, when the feed to the spiral has a larger size distribution, the enrichment ratio of the feed is 1.32 and, with the smaller feed size, this value has increased to 1.99. When the spiral feed has a larger size distribution and higher specific gravity, the recovery of chromite increases with increasing particle size up to 250 microns, and then with increasing particle size, recovery decreases with a relatively steep slope. Evaluation of spiral efficiency with respect to particle liberation degree has also shown that despite the high degree of liberation of spiral feed in size fractions smaller than 75 microns (88.9%), the liberation degree of spiral concentrate and tail in this faction is equal to and less than that of feed, which can indicate poor spiral performance in these size fractions.

Oct 27, 2020

By J. M. B. Scarborough

This paper deals with measures taken to maintain effective operation of heavy-duty equipment in open-pit mining. at Pine Point, N.W.T., during periods of extreme cold weather. The points covered include equipment modifications designed to improve cold-weather performance, effective lubrication of machinery that is vulnerable to extreme cold and operating procedures designed to prevent equipment damage.

Jan 1, 1966

By T. H. Davis

Twelve laboratories from the Western United States and Canada participated in radon progeny intercomparison measurements at the U.S. Bureau of Mines radon calibration facility in March 1987. The participants intercom pared grab-sampling and automated equipment methods at high and low concentrations of radon progeny and condensation nuclei (CN). The objective of this intercomparison was to determine if the measurement procedures and equipment of the North American facilities are equivalent. The sampling results showed good agreement among all participants. The standard deviation for the working level measurements was less than 3.5% for 1.70 working level (WL) and less than 8.8% for 0.21 WL. This relatively good agreement was achieved by using alpha standards calibrated by National Bureau of Standards (NBS) and by closely checking and monitoring airflows.

Jan 1, 1989

By A. Lyndon

Combined loading tests are described to three 1.2m diameter cast-in-place bored piles, 12m long, formed through cohesionless material into stiff sandy clay. The maximum loading conditions imposed at the pile head were 2400 kN vertical, 160 kN lateral and 3120 kNm in bending, corresponding to twice the working load. Settlements, deflections and rotations of the piles were measured during the tests. An interesting finding which the test results suggest is that, in the short term, vertical movement had apparently no marked effect on lateral performance for piles working at design loadings.

Jan 1, 1989

By C J. Coveney

This paper, after a brief introduction to the mineralization and structure in the mine area, outlines the methods now being employed for grade control at Bethlehem Copper Corporation. Sampling, subgrade drilling, blasting and the actual outlining of the ore are among the topics covered. The paper concludes with a summary of the results obtained, showing a reduction in dilution and an improvement in the grade of the copper ore going to the mill. Introduction T HE Bethlehem property is located in southern British Columbia in the Highland Valley about 30 miles southeast of the town of Ashcroft. The property is located within the Guichon batholith. The rock comprising the batholith is a massive, coarse-textured diorite, which, at Bethlehem, has been intruded by a younger quartz diorite, porphyries and breccia, referred to as the "Younger Complex." Mineralization, consisting of chalcopyrite and bornite with minor pyrite and molybdenite, occurs as disseminations, fracture fillings and coarse blebs. The ore zone lies close to the Guichon -Younger Complex contact where, prior to the development of the breccia, the rocks were shattered and jointed. Subsequent mineral

Jan 1, 1965

By H. E. Cline, E. F. Koch, J. L. Walter

It has been postulated and, in a few instances shown, that some kind of dislocation structure will be present at semicoherent interfaces to accommodate small lattice mismatches. In the present study of the NiAl-Cr eutectic, regular arrays of interface dislocations are observed at the boundary between the chromium-rich rods and the NiAl-rich matrix. The networks were examined by transmission electron microscopy and selected area diffraction. The rods and the matrix have a crystallographic relationship in which all directions and planes of the two phases are parallel. The dislocation networks are cmposed of a<100> dislocations lying on the intersections of the cylinders with (100) planes. Dislocations forming hexagonal rather than square arrays are also observed at certain areas of the network. The morphology of the network is consistent with the interpretation of mismatch being accommodated by interface dislocations in the cylindrical geometry. The measured spacing between dislocations was used to calculate an apparent lattice mismatch between the phases (˜0.35 PCt)interface network energy (-140 ergs per sq cm), and network strengthening (-10,000 psi). It has been proposed by Frank and Van der Merwe1 that dislocations should be present at the boundary between two semicoherent crystallographically related phases. The role of the interface dislocations would be to reduce the internal stresses, caused by the mismatch in atomic spacing across the interface. Such dislocations have been observed at the interface between expitaxially grown films and Substrates.2-4 Interfacial dislocations have also been observed at precipitate-matrix interfaces.&apos;-&apos; Directionally solidified eutectics have been shown to have semicoherent phases1&apos; and would, therefore, be expected to have interfacial dislocations as found by Weatherly at a lamellar fault in A1-A12Cu.11 The NiAl-Cr eutectic appeared to be a promising system to examine because both phases are cubic, the lattice mismatch is small, and the phases are crys-tallographically related. Furthermore, the eutectic is easily thinned for transmission microscopy. Indeed, interfacial dislocations were observed and this report describes the nature of the dislocation networks in the boundary between the NiAl-rich ma-trix-phase and the fine chromium-rich rods.21 I) EXPERIMENTAL PROCEDURE Ingots, 3/4 in. in diam and 6 in. long were made by melting in vacuum and casting under argon using 99.9 pct pure material. The composition, in at. pct, was 33 pct Ni, 33 pct Al, and 34 pct Cr. The ingots were then placed in A1203 crucibles on a water-cooled base, melted by means of induction, and withdrawn from the hot zone at the rate of 1 in per hr under argon.* * T his material was first directionally solidified in this laboratory by E. R. Stover Slices were taken perpendicular to the growth direction of the directionally solidified ingot for metallography and for transmission electron microscopy. The electron transmission samples were thinned mechanically, then thinned electrolytically in A-2 electrolyte* *A-2 electrolyte: 62 ml perchloric acid, 700 ml ethanol, 100 ml butylcellosolve, 137 ml distilled H20. until a hole appeared in the foil. 11) EXPERIMENTAL RESULTS A) Optical Microscopy. The microstructure, viewed on a plane perpendicular to the growth direction, is shown in Fig. 1. The structure consists of cells or colonies of parallel chromium-rich rods in the NiAl matrix. The cells occur when there are impurities present12 or, in a ternary eutectic, if the composition is slightly off the eutectic composition. The axis of the chromium-rich rods is parallel to the growth direction except near the cell boundaries. Here the rods may assume angles to the growth direction; however, examination shows that the crystallographic relationship between the rod and the matrix remains the same. Fig. 1 includes cell boundaries where the rods formed at a large angle to the growth direction. The variation of rod position across the cells made it possible to Fig. 1-Structure on plane perpendicular to growth direction. Rods near cell walls are at large angle to growth direction. Magnification 315 times.

Jan 1, 1970

By R. V. Higgins

This report presents the results of a study of gas injection in the Upper and Lower Terminal zones in fault block VB and in the Upper Terminal zone in fault block VI, Wilmington field, California. This report is based on data obtained to January 1956. Earlier studies of gas injection in other California fields have been reported .3/ The Upper and Lower Terminal zones, fault block VB, have been producing oil since 1945 and the Upper Terminal zone, fault block VI, since 1948. Before starting the gas-injection project, the expansion of dissolved gas was the principal mechanism moving the oil to the wells. Gravity drainage and an edgewater drive also have contributed to the movement of the oil to the wells. When the gas injection was begun, the reservoir pressure and the oil production had declined appreciably. Gas injection was started in the Upper and Lower Terminal zones, fault block VB, in May 1953 and in the Upper Terminal zone, fault block VI, in October 1953.

Jan 1, 1957

By R. N. Gow

EH-pH diagrams are useful tools in understanding how mineral surfaces react in solution and particularly how aqueous conditions can be changed to enhance mineral leaching processes. However, successful application of these diagrams requires several things be kept in mind to prevent what others have termed ?gross errors? in their calculation and use. The aqueous Cu-S system is used as the basis for explaining the mass-balanced method of calculating EH-pH diagrams with the thermodynamic equilibrium software, STABCAL. This includes a breakdown of the Gibbs? Phase Rule and how it is employed in STABCAL to modify the diagrams. This methodology was then applied to the aqueous Cu-As-S system and resulting diagrams are compared against examples of those generated using the predominant-ion method. The resulting mass-balanced diagram for enargite (Cu3AsS4) is noted to compare well with spectroelectrochemical measurements using Raman spectroscopy and cyclic voltammetry.

Feb 23, 2014

By R. Dehghan, M. Zarei, A. Tohry, S. C. Chelgani

Typical depressants for selective reverse flotation of iron oxides from complex silicates do not generally show high levels of efficiency. Therefore, as a hot topic, there are several ongoing investigations in this area. The main aim of this paper is exploring the potential of using humic acid (HA) as a depressant in reverse cationic flotation of hematite from complex silicates. For such a process, the wettability and flotation behaviour of pure minerals (hematite and silicates) was investigated at pH 10 in the presence of HA and cationic collector. Adsorption mechanism of HA on these minerals was measured by zeta-potential and FTIR. Results of flotation tests showed that at the lower concentrations of HA, selective separation of silicates from hematite is beneficial, where the floatability of amphibole was higher than pyroxene. A higher separation efficiency of hematite through reverse flotation was observed in the presence of amphibole, in comparison with the presence of pyroxene. Wettability studies showed that HA has a significant effect on reducing the hydrophobicity of treated minerals with the collector. The adsorption, ZPC and FTIR test results indicated that HA was adsorbed on both silicates and hematite. However, the absorption intensity onto hematite was much higher than silicates. It was found that the adsorption mechanism of HA on hematite takes place through both strong H-bonding and ligand exchange. Keywords: Reverse cationic flotation, humic acid, iron oxide, complex silicates, surface adsorption

Jan 1, 2020

By G. C. Anderson

The Cleveland Cliffs NOLA electronics and software upgrade is a Windows based system that simultaneously controls two Texas Nuclear NOLAs and associated sampling. It uses new spectrum analysis and algorithms to produce accurate, linear silica measurement with slurries that range from 5 through 50 percent solids. This linearity allows us to achieve a reproducible procedural calibration. The hardware consists of readily available shelf items, is extremely redundant and eliminates all NIM bus modules.

Jan 1, 2003

By Shiro Watanabe

To determine the potentialities of nickel as a substitute for cobalt in catalysts for the synthesis of hydrocarbons from carbon monoxide and hydrogen, RESULTS The maximum oil yields obtained in bench-scale equipment were as follows: Using 100N1:20Mn:100 kaolin:200 diatomaceous earth catalyst, a maximum yield of 133.8 cm.3/m.3 of pure CO+2H2 was obtained from one pass of the feed gas, With a nickel:cobalt mixed catalyst (Ni:Co - 3:7) having the composition 100(Ni+Co):8MgO: 5Th02:200 diatomaceous earth, a maximum of 172.2 cm.3/m.3 of pure C0+2H2 was obtained.

Jan 1, 1951

By D. B. Kibler

THE Florida hard-rock field extends from Suwanee and Columbia Counties in northwest Florida to south of Croom, Florida, in Hernando County. This area is approximately 100 miles long and varies from 2 to 30 miles in width. Florida hard-rock phosphate was discovered at Hale Springs, about one mile northwest of the town of Dunnellon, Marion County, in the year 1888, by Albertus Voight, who lived within a few hundred yards of the spring. Soon after this discovery there was a great influx of land speculators and wildcat operators into the vicinity of Dunnellon. A few years later phosphate was found in Alachua, Levy, Citrus and Hernando Counties, and a great number of small crude plants were built from Newberry, Alachua County, all the way to Croom, Hernando County. Phosphate was found in many places as "outcrops." Looking for outcrops was the first method used by the early prospectors in searching for deposits. Several years passed before any systematic method of prospecting was used. EARLY MINING The early method of mining hard-rock phosphate was with picks and shovels, wheelbarrows, mules and wagons. The pick-and-shovel method was used altogether until about 1900, when some of the larger operators began to use railroad-type steam shovels of from ½ to 1-yd. capacity. Picks and shovels, with negro labor loading the phosphate ore (called "matrix") into wooden side-dump skip-cars, was continued until about 1907. From the discovery of hard-rock phosphate until approximately 1905, overburden was removed with mules and scrapers. At some places, the overburden was loaded into side-dump skip-cars by negro laborers and the cars were then pulled up an incline with a steam hoisting engine. The maximum depth of overburden that could be economically removed by hand labor, mules and scrapers was approximately 15 feet. About 1905 one of the companies erected a producer-gas powerhouse near Dunnellon and generated its own electricity and about the same time the larger companies began using hydraulic methods for the removal of overburden. From the year 1888 through the year 1939, approximately 75 companies were operating at one time or another in the hard-rock territory, on approximately 500 locations. The hard-rock deposits are more irregular and have higher mining costs than the pebble-rock deposits, therefore they have not been competitive in the domestic market, but because of the higher grade of the hard rock it is in demand for the export trade. Discovery of phosphate outside of the United States has made it increasingly difficult in recent years for the hard-rock companies to survive, so today only three companies are operating. These

Jan 1, 1941