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By M. Loan

The Zinifex's Hobart Smelter uses the paragoethite process to remove dissolved Fe(III) from concentrated zinc leach liquors. This produces a residue consisting primarily of 6-line ferrihydrite (a hydrated Fe(III) oxyhydroxide), several insoluble components derived from the calcined zinc concentrate neutralization agent and other precipitated phases, such as jarosite and silica. The precipitation of 6-line ferrihydrite in the paragoethite process was studied using a laboratory-scale continuous crystallizer, and the conditions were selected to limit high levels of dissolved silica and jarosite. This approach allowed the reactor pH and the rate of precipitation to be correlated with residue solid-liquid separation, particle size, morphology, residual zinc and sulfate concentrations, and phase formation (e.g., goethite, jarosite, schwertmannite, and 2- and 6-line ferrihydrite). These studies delineated the mechanism of 6-line ferrihydrite precipitation in the kinetically controlled paragoethite process, and its inter-relationship with goethite and jarosite precipitation under conditions where 6-line ferrihydrite is favoured. Unexpectedly, the generation of a more crystalline goethite precipitate with larger "primary" particle size did not produce a residue of improved properties, as bulk aggregates dictate the physical properties of the residue and not the crystallinity. Furthermore, it is difficult to precipitate 2-line ferrihydrite or schwertmannite under existing paragoethite process conditions.

Jan 1, 2006

By P. H. Floyd

This report presents the results of laboratory and continuous mill-beneficiation tests conducted at the Bureau of Mines Northwest Electra Development laboratory, Albany, Oreg., on nonsulfide lead ore from the Sherman mine, Leland district, near Burke, Idaho. The predominant lead-bearing mineral in the ore sample treated was pyromorphite, a minor ore mineral of lead. Known reserves of pyromorphite lead ore in the United States are limited, although an appreciable tonnage of this type of ore is found in the Sherman mine. Very little pyromorphite is being mined in this mine or in the United States. This beneficiation problem presented a unique opportunity to study the mineral-dressing properties of a less widely known lead mineral, and consequently adds valuable knowledge to the ways of beneficiating ores containing nonsulfide lead values. This mineral-dressing problem was successful with conventional concentration methods of flotation and Gravity separation.

Jan 1, 1952

By M. B. Bransford

A calculation procedure was evolved by the Bureau of Mines for determining the heat-transfer characteristics of dilute gas-solid mixtures in an externally heated tube. The procedure accounts for differences in gas and particle velocities and covers a range of particle sizes. Heat transfer coefficients obtained by the calculation procedure are compared with values reported in the literature.

Jan 1, 1970

By Peter D. Lohn

The Bureau of Mines conducted both laboratory and field investigations to study the effectiveness of medium-pressure (up to 30,000 psi) water jets in controlling the generation of airborne respirable dust during the hydraulic fragmentation of coal. Laboratory studies were conducted at the Farmington High Energy Test Site of the Twin Cities Mining Research Center, and field studies were carried out at the Humphrey No. 7 mine, Mount Morris, Pa., in the Pittsburgh coalbed. The water jets were produced by commercially available triplex pumps. The dust samples were collected by midget impinger samplers, and analyzed by electronic and optical counting techniques. Respirable dust concentration for a full-scale production model was projected at below 2 mg/m3, the maximum exposure allowed by the Federal Coal Mine Health and Safety Act of 1969.

Jan 1, 1975

Iron deposits of every major type except laterite occur in Quebec, and form one of the major iron ore resources of the world. The five principal types of ore described are: (1) hematite-goethite masses derived from iron formation through the oxidation and enrichment of iron by natural processes; (2) taconites consisting of fine-grained iron formation; (3) metataconites composed of coarse-grained iron formation; (4) iron and titanium oxide minerals in massive or disseminateed deposits within gabbro and anorthositic rocks; and (5) replacement or contact? metasomatic magnetite deposits associated with complex silicate and skarn mineral assemblages. Most of the ore, although relatively low grade, is easy to concentrate. The physical properties of the ores that affect the choice and efficiency of beneficiation methods are described. The extent to which iron ore from this area can be utilized in the future will depend on the continued use and improvement of highly efficient methods of beneficiation.

Jan 1, 1964

By C. E. Jordan

The U.S. Bureau of Mines investigated flotation hydrodynamics to improve the recovery of coarse phosphate. Fluid velocity profile measurements were used to characterize the hydrodynamics within commercial phosphate flotation cells and laboratory flotation cells. The effects of agitation, aeration, and pH on coarse phosphate recovery were measured in the laboratory flotation cells and correlated with the hydrodynamics measurements. Test results revealed that the agitation energy and aeration level had a significant effect upon flotation response. By optimizing these two parameters, 92 pct of the phosphate was recovered in a rougher flotation concentrate grading 28 pct P2O5?

Jan 1, 1994

By Paul Gottlieb

This paper reviews the status of automated applied mineralogy today and describes the history and fundamental theoretical and practical bases underpinning the development of automated systems. Details are given of the technical challenges that were faced in creating the new technology and in applying it to a range of applications. In recent years, automated mineralogy has become established as an essential enabling technology for the reliable acquisition of statistically sound comprehensive mineralogical and metallurgical data. This has had a revolutionary effect on the industrial use of such data in the study of geology, mining and mineral processing. Previously, using manual methods, it was not feasible to attempt this work because the large data sets required could not be assembled in a realistic timescale. There was a reliance on individual expert mineralogists and this was not scalable. The speed, reliability, detail and repeatability of the modern automated measurements has now made this type of analysis routine. Automated Applied Mineralogy has come of age! More than 100 systems have been installed around the World. Automated mineralogical analysers such as QEMSCAN® were originally developed as diagnostic metallurgical tools to improve mineral processing plants using samples drawn from plant surveys, bench and pilot-scale tests. They were used mainly for the assessment and auditing of size fractions of mill products, such as concentrates and tails. Subsequently, they began to be used for concentrator design and optimisation where ore characterisation was used to help understand the relationship between the feed ore and its subsequent behaviour in the plant. They are now widely used to measure exploration cores and drill chips from drilling programs to predict eventual metallurgical performance. Ore samples can be classified into metallurgical, as well as geological types, by combining mineralogical features in the ores with metallurgical properties related to grade control, separation, comminution, flotation and leaching behaviour. Three-dimensional block models of ore deposits are now being created based on processing response in addition to geological and mining properties. The development of automated systems began in Australia, the United Kingdom and Canada in the late 1970s and early 1980s. There were many technical challenges. Mathematical theories of randomness, sampling theory, image analysis and stereology were developed to ensure sample representivity so that meaningful information could be obtained. Sample preparation, presentation and measurement methods were developed to ensure that the random sampling was preserved during the measurements. Methods of automatic measurement and mineral identification evolved from the use of electron microscopes, fitted with backscattered electron brightness and energy dispersive X-ray detectors. Operational procedures were required to ensure that these instruments could accommodate a large number of samples and operate unattended for long periods of time. The new technology was progressively applied to a range of commodities and applications and new analysis methods, such as liberation measurement, were needed for metallurgical interpretation of mineralogical data.

Jan 1, 2014

By A. O. Orumwense

Mill circumferential speed, the number of passes of pulp through the grinding chamber, media type, size and filling ratio were investigated in an attempt to determine how to effectively grind copper concentrates in a stirred mill. The stirred mill product fineness was enhanced to some extent by decreasing media size, high media filling, and an increased number of passes of the pulp through the grinding chamber. Shape also plays a major role in grinding media effectiveness, with spherically shaped media producing a finer size. The fineness of the product increases with increasing power consumption but the method of energy transfer is very important in energy utilization. The effect of the mill parameters on copper flotation was evaluated. Copper recovery was influenced by grinding media size, mill speed and the number of pulp passes through the grinding chamber.

Jan 1, 2006

By E. J. Lintner

This paper is one of a series being prepared by the United States Bureau of Mines describing clay mining, crushing and grinding methods, and costs at various clay-mining operations throughout the United States. These papers are designed to disseminate technical information regarding methods used. The cost tabulations represent local operating expenditures only and not total production costs. Although the publication of total production costs might not be advisable in some instances, yet a knowledge of operating costs is essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to-this distinction between total and operating costs in order that no misunderstanding of the cost tabulations shall ensue. The following report deals specifically with the methods employed by the Dennison Sewer Pipe Co., Dennison, Tuscarawas County, Ohio.

Jan 1, 1936

By N. Vorob?ev-Desyatovskii

The process of gold(I) adsorption on activated carbon (AC) from aqueous Na[Au(CN)2] and the state of the adsorbed gold cyanide complex on the adsorbent surface was investigated by photometry, XPS, XANES methods. By DFT method, quantum-chemical calculations were performed of the gold cyanide species on activated carbon surface. It was established that the binding of gold(I) with the surface of carbon involved several simultaneous processes governing the selective adsorption of gold(I) from the cyanide solutions.

Sep 1, 2012

By K. Louk, E. Gilliland, N. Ripepi, M. Karmis

"Carbon dioxide (CO2) injection in deep unmineable coal seams can enhance coalbed methane (CBM) recovery as well as effectively and permanently store the CO2. Enhanced coalbed methane (ECBM) recovery and CO2 storage capacity can be improved by altering injection parameters including the injection well locations, number of injection wells, and the time and rate of the injection. A sensitivity study was performed with sixteen different injection scenarios on a coalbed methane field in Buchanan County, Virginia to understand the influence of the injection parameters on methane production, CO2 storage and the extent of the CO2 plume. History matching was done for the gas and water production period prior to injection based on field data from an active US Department of Energy funded pilot project. INTRODUCTION The coal structure is a combination of the coal matrix and cleats. In a CBM reservoir, the methane (CH4) is stored in the matrix under adsorption properties, not as a free gas. During CH4 production, the reservoir pressure is reduced and gas is released from the surface of the coal, diffuses through the matrix and transmits to fractures (man-made or natural) via the cleat network. Fractures and cleats are the major parameters that influence gas flow capacity because deliverability of the CH4 to the production well is controlled by the cleat permeability. As gas production continues over time, CH4 desorbs from coal, and coal matrix volume starts to decrease. This volume decrease in the matrix opens up the cleats, matrix shrinkage, which leads to a permeability increase. Several emprical (Harpalani and Schraufnagel 1990a, 1990b; Harpalani and Chen 1995, 1997; Harpalani and Mitra 2010; Pan et al. 2010; Liu et al. 2012; Mitra et al. 2012) and analytical (Palmer 2009; Liu and Harpalani 2013) studies have reported this relationship between pressure and permeability. Those studies showed that permeability is an important parameter in CH4 production performance. Furthermore, during gas production, water is produced through the cleat system as well, therefore gas-water relative permeability must be also considered in evaluating production performance (Gash et al., 1991). In the CO2 injection scenario the opposite occurs because CO2 has a higher adsorption affinity than CH4. CO2 replaces CH4 in the matrix of the coal and increases the volume of the coal matrix, matrix swelling, and results in a permeability decrease. Harpalani and Mitra (2010) concluded in their experimental study that swelling of the coal matrix due to the CO2 injection is two to three times more than the sorption of CH4, resulting in large permeability changes during CO2 injection."

Jan 1, 2016

By L. G. Marshall

This report is one of a series published by the Federal Bureau of Mines describing mining methods and performance at individual operations throughout the United States. The objective of these papers is to promote development and conservation of our mineral resources by disseminating reliable technological information on mining methods, practices, and results that may be applied to the engineering analysis and solution of mining problems. SUMMARY Operation of a limestone quarry producing flux for the steel industry and crushed stone for production of concrete is described in this report. The deposit being mined is a flat-lying limestone formation under a thin overburden 2 to 25 feet thick. The height of the quarry face varies from 9 to 60 feet, averaging 40 feet. Production rate ranges from 4.5 to 5 million long tons per year.

Jan 1, 1959

By L. B. Berger, W. P. Yant, J. B. Littlefield

"INTRODUCTION Hydrogen sulphide (H2S) is one of the most toxic industrial gases and of relatively wide occurrence in industry. Among its common industrial occurrences are, in the production and refining of high-sulphur petroleum, in natural gases, in gypsum and sulphur mining, in rock strata and underground waters (where it is encountered in tunneling and caisson work) in blasting with black powder and in blasting high-sulphide ores with other explosives, in gas manufacture, in the carbonization of coal, and in the manufacture of chemicals.The usual methods of detection, other than by the sense of smell, which is lost in 2 to 15 minutes' exposure to 0.010. to 0.015 percent of this gas, 5/ either are too cumbersome for frequent and rapid analyses or, like the wet lead acetate paper test, afford only qualitative results. A qaantitative determination usually involves the use of solutions, bubblers, flowmeters, standard solutions, burettes, and indicators manipulated by trained technical men. All apparatus and methods in common laboratory use are, in general, unsuitable for the field.The physiological response attending exposure to various Concentrations of hydrogen sulphide in air, is as follows, in percent by volume 6/:0.005 to 0.010: Subacute poisoning - slight symptoms, such as mild conjunctivitis and respiratory-tract irritation after 1-hour exposure."

Jun 1, 1935

By J. Ambrose, R. W. Zimmerman

"Shales are highly anisotropic in their mechanical behavior. The strength ( ??1) of anisotropic shales depends not only on the magnitude of the other two principal stresses ( ??2, ??3), but also on the bedding plane orientations (?) relative to the principal stresses. In this study, the role of the intermediate stress ( ??2) on the strength of shale is evaluated using new data from triaxial compression and extension tests. To understand the failure behavior of shales, we have carried out triaxial compression tests ( ??1 > ??2 = ??3) on two organic rich mudstones, at different confining stresses and loading angles. We first fit the triaxial compression data with Jaeger’s plane-of-weakness model, and find that the model is able to represent the strength behavior of anisotropic shales reasonably well. We then carried out five triaxial extension tests ( ??1 = ??2 > ??3) for a high strength-anisotropy shale, and two extension tests for a low strength-anisotropy shale. Results from the compression and extension tests for failure along the weak plane shows that the role of ??2 is not significant for weak plane failure. However, for the low strength-anisotropy shale, the failure strength of the intact rock (i.e., at ??= 0o and 90o) for compression and extension tests were significantly different. This indicates that for intact rock failure, the role of ??2 is important and cannot be ignored.INTRODUCTIONFor many years, various researchers have studied the roles of ??2 for failure of isotropic rocks. (Mogi, 1967 and 2007; Colmenares and Zoback, 2002; Al-Ajmi and Zimmerman, 2005 and 2006; Haimson, 2009; Ma and Haimson, 2012). The findings from these studies show that the effect of ??2 on the strength of isotropic rocks is generally significant, and cannot be ignored.Since the role of ??2 in the failure of isotropic rocks was recognized, other researchers attempted to extend some of these isotropic failure criteria to anisotropic rocks, but with limited success (e.g., Tiwari & Rao, 2007; Singh et al., 1998; Zhang and Zhu, 2007; Pei, 2008). Smith and Cheatham (1980), on the other hand, conducted true-triaxial experiments on the Green River Shale and used a J2-I1 type relationship to predict the strength behavior, but without considering the effect of the three-dimensional orientation of the weak plane on strength. Therefore, unlike for the case of isotropic rocks, additional studies need to be done to determine the role of 2 on the failure of anisotropic rocks."

Jan 1, 2015

"IntroductionNOTE.-All figures on the supply and consumption of coal in Canada cited in this paper were collected and reported by the Dominion Bureau of Statistics. The friendly and efficient co-operation of the officials of the Bureau. is the foundation upon which it has been my privilege to rely in the preparation of this and two earlier papers ( 1). My thanks are due also to our own staff on the Dominion Coal Board, who spared neither time nor effort in helping to prepare this paper.STATISTICS are comparatively dull and, to many people, coal statistics are duller than most. Coal is, however, the one basic mineral upon which our whole way of life depends and it may be well if attention is drawn to this fact by an occasional statistical review of the coal position in Canada. The recent furore over the oil and gas discoveries has so obscured the basic position of coal in many minds that a little basic coal information may be useful. It is for this reason that, for the third successive year, a factual survey of the coal position is being presented.In the previous papers (1) explanations have been given of the basic considerations in the preparation of these reports and some special phases of the overall picture have been examined. For these explanations, the earlier papers may be consulted."

Jan 1, 1952

By D. Boreck

The Bureau of Mines is conducting research on the feasibility of incorporating in situ stope leaching into active underground metal mines. Stope leaching, a modified in situ leaching technique, proposes to recover metals by leaching fragmented ore in existing underground openings and collecting and processing the metal-bearing solution to recover the valuable metals. If leaching solutions escape from the stope, either through geologic discontinuities or highly permeable zones in the rock, valuable metals dissolved in the solution may be lost. Escaping solutions may also contaminate ground waters. Consequently, in fractured rock, the characteristics of the fractures in the vicinity of the leaching stope must be understood before introducing actual leach solutions into the stope. Effectively characterizing a rock mass requires the integration of several disciplines including structural geology, borehole geophysics, hydrology, geochemistry, and mining engineering. This paper will focus on the general geologic and geophysical techniques that can be used to characterize the rock mass at an underground simulated stope leaching site. The results of several geophysical logging methods, tested at the site, are compared to the geologic core descriptions. Then, the? effectiveness of the different geophysical techniques in delineating fracture zones will be assessed. Knowledge gained through the geologic and geophysical analyses can be used to supplement results from hydrologic testing. This information can also be utilized in designing blast patterns and developing strategies for controlling or blocking movement of escaping leach solutions.

Jan 1, 1991

By L. Keith Hudson

The purpose of this study is to provide data that demonstrates that the Alcoa flash calciner design can be used for the decomposition of AlCl3?6H2O to A1203. Heat and material valance data for calcination provides data on the partial pressure of HCl in the off-gases. Experimentally determined data for the HCl partial pressure, over solutions expected in producing alumina from clay by the hydrochloric acid process, show that HCl can be absorbed from the off-gases into process solutions to effect crystallization of AlCl3?6H2O.

Jan 1, 1979

By T. S. Spicer

Inflammability and crossing point apparatuses were used to study the influence of increasing amounts of such inerts as ash, fly-ash, pyrite, limestone and Portland cement with several pulverized bituminous coals. The results indicate that it requires large proportions of inerts to substantially suppress the ease of ignition.

Jan 1, 1962

By D. D. Munro

Finsch Mine is a Kimberlite diamond mine located at Lime Acres in the Northern Cape of South Africa. The mine was founded in 1961 and started surface-mining in 1964. Underground production commenced in 1990 using a Modified Blast Hole Open Stoping method for the mining of Blocks 1,2 and 3. Block 4 is currently being mined as a Block Cave. The process of identifying and optimizing a mining method to mine the Block 5 ore body started in 1991 and in 2006 Inclined Caving was identified as being a technically feasible method. This report aims to document the process employed in developing this method by the Block 5 Pre-Feasibility Team as well as discussing the technical challenges encountered during this process.

Jan 1, 2010

By David A. Benjamin

The USBM (U.S. Bureau of Mines) studied mines, prospects, and mineralized sites in the Roberts WSA (Wilderness Study Area) in 1984. The 15,090-acre WSA, located 35 miles northwest of Eureka, NV, is underlain by alluvial deposits of Quaternary age, extrusive and intrusive volcanic rocks of Oligocene through Miocene age, and metasedimentary rocks of Cambrian through Permian age. The Roberts Mountain Thrust fault cuts through the WSA, dividing the metasedimentary rocks into upper and lower plate rock units. One mine, the Kelley, which produced 397 tons of lead-zinc ore prior to 1940, and two prospects are within the WSA; no resources were identified. Exploration for precious metal deposits is presently being conducted in and adjacent to the WSA on large claim blocks. The study area contains six sites in and near these claim blocks that have anomalous gold and silver. Detailed exploration is needed to delineate resources. High purity silica rocks are present in the WSA. Barite, phosphate, oil shale, and vanadium occurrences just outside the WSA may extend into it, but no such occurrences were observed during the USBM study.

Jan 1, 1986