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By Arthur B. Johnson

The Bureau of Mines investigated the concentration characteristics of high-clay sylvinite ores from four potash companies operating in the Permian Basin near Carlsbad, N. Mex. These ores, containing 13 to 22 percent K20 and 3 to 7 percent clay slimes, cannot be effectively processed by current commercial flotation methods because of their high slime content. A solution to this problem was shown to be the use of two-stage moderate scrubbing conditions and washing of the ore as opposed to strenuous attritioning. Bench-scale physical beneficiation techniques for recovering potash minerals and the development of ore-dressing systems by flotation resulted in obtaining acceptable product grades and recoveries. By using a coarse grind, emphasis was placed on production of premium granular and coarse products. Flotation results showed that concentrates of 58.7 to 60.4 percent K20 with recoveries of 71.0 to 83.4 percent 0f the K20 values can be obtained.

Jan 1, 1971

By S. P. Singh

In order to simulate the operation of coal extraction machines, a portable workability instrument has been designed. Initially, the tests were performed with the instrument on modeling material, which were followed by in situ tests on coal in underground mines. The peak and mean cutting resistance and work done to cut a unit length of coal were determined for coal as well as modeling material. In addition, rebound strength and dynamic penetration tests were also performed in situ. On the basis of the cutting characteristics of coal, a "Workability Index" has been developed and its role in the judicious selection of coal cutting machines has been discussed. With reference to prior works and the strength characteristics of coal, it was found that the coal plow may not be suitable for the seams under investigation and the shearer seems to be the only choice. It has been observed that peak cutting resistance and the "Workability Index" in the case of coal as well as modeling material depend upon compressive strength. The peak cutting resistance exhibited certain dependence upon the Schmidt rebound hardness and dynamic penetration strength of coal in situ.

Jan 1, 1984

By Real Daigneault, François Robert, J. Paul Golightly, Jean-Yves Cloutier, Jayanta Guha, Pierre Pilote

"The Casa-Berardi East, Center and West deposits, located in the Archean Abitibi, Sub province, are hosted by volcanic and sedimentary units of varying compositions, less than300 m from the Casa-Berardi fault (CBF). The CBF, a brittle structure, represents an increment in the structural evolution of a regional-scale deformation zone showing ductile-brittle behavior known as the Casa-Berardi deformation zone (CBDZ). The CBDZ is characterized by a mylonitic Sc1 foliation which is folded a.n4 deformed by a later sczfoliation in high strain zones.Four generations of quartz vein and fracture systems have been recognized within the Casa-Berardi deposits. Most economic gold mineralization, occurring in the second generation system, is found within high strain zones. This system hosts three types of mineralized structures: (1) banded quartz veins; (2) swarms of veins and mineralized host rocks; and (3) disseminated sulphides along fractures. An early carbonate hydrothermal alteration zone (pre- to syntectonic) surrounds the deposits. Alteration associated with gold mineralization is contemporaneous to late ( syn- to post-tectonic) relative to the development of progressive deformation in the CBDZ. The geological characteristics and paragenesis of the four quartz vein and fracture systems developed as an integral part of the geodynamic evolution of the Casa-Berardi deformation zone."

Jan 1, 1990

By Gang Mei, Nengxiong Xu, Yanlin Zhang

After open-pit mining finishes, an iron mine with steeply inclined ore-bodies will generally transform to underground mining. Non-pillar sublevel caving method, with horizontal slice mining from up to down, is commonly used for mining deep ore-bodies under the open-pit bottom. As horizontal slice mining proceeds, a gradually enlarging goaf will be formed under the open-pit bottom, the rocks surrounding the handing and heading sides of the goaf will collapse continuously, and then these results in rock-mass failure with large deformation and displacement in the open-pit slope. Based on FLAC3D, a modeling approach to predict pit slope deformation and failure induced by transitioning open-pit to underground mining is proposed in this paper. This method mainly consists of three procedures of modeling, i.e., mining modeling, landslide modeling, and filling modeling, of which landslide modeling is the core of the proposed approach. In the procedures of modeling with FLAC3D, iteration non-convergence is taken as a local failure criterion of pit slope. When iteration calculation cannot converge, the sliding modeling will start by deleting some elements with large displacements, and finish until convergence. Before modeling landslide, several displacement contours of rock-masses in the pit slope are searched out, and each contour is an approximate possible sliding surface of the open-pit slope. From these contours, the most proper one is selected as the slope sliding surface by using the iteration calculation convergence and minimum element deletion as the judgment condition. Landslide modeling is then realized by removing the elements outside the slope sliding surface. Finally, to demonstrate the effectiveness, the proposed approach is used to simulate the process of open-pit to underground mining at Yanqianshan Iron Mine, and to predict the deformation and failure characteristics of open-pit slope during underground mining. The case study results show that: the prediction of the slope stability determined by using our method is consistent with that calculated by using the limit equilibrium methods.

Jan 1, 2015

By G. Akdogan, P. Mutimutema, M. Tadie

The South African gold mining industry has a legacy of abundant tailings dams, which have attracted the attention of investors because of their potential as a cheaper secondary gold resource. In this we investigate study gold recovery from a refractory calcine tailings dam. Bulk mineralogy of the tailings silicates and iron oxides to be the most abundant phases. Scanning Electron Microscopy (SEM) showed gold to exist in submicrometre and micrometre sizes, as free gold, and associated with arsenic, sulphur, and silicates e.g. quartz and talc. Gold recovery by direct cyanidation was low at 17.3%. Mechanical (ultra fine grinding P80 -16μm) and chemical (alkaline, NaOH) pre-treatment and microwave roasting and microwave-assisted cyanide leaching were investigated to increase gold recoveries. Ultrafine grinding was the most effective, producing recoveries of 66.5%. NaOH pre-leaching of ultrafine milled material increased recovery to 71.5%. Alkaline pre-leaching overall increased recoveries for non-pretreated material, making this process the most preferred because it is less costly than ultrafine grinding. Microwave roasting and microwave-assisted leaching did not achieve higher recoveries than alkaline pre-treatment or fine grinding. The investigation highlights and confirms that chemical treatment with NaOH is a powerful tool for gold extraction from refractory tailings.

Oct 1, 2022

By AIME AIME

THE 122d meeting of the Institute was held in the Lake. Superior Copper and Iron Country Aug. 20 to Sept. 3, 1920 with an approximate registration of 1100 members and guests. This is the 'first visit of, the Institute to this vicinity since 1904 although previously it held meetings there every six or, seven years. 'The eastern party assembled at Buffalo and sailed on the S. S. "Tionesta ". on Friday morning, Aug. 20, arriving at Houghton, Mich., Monday, Aug. 23. En route stops were made at Detroit, where sightseeing auto trips were taken, and at Mackinac Island, where a short stop permitted a visit to the picturesque and historic Fort Mackinac.

Jan 1, 1920

By Jim Buckley, Ryan Sibley, Scott G. Giltner, Thomas Pallua, Joe Schrank, Robert Cidlik

Because of variation in rock type and site conditions, it is important to create site-specific prediction models for peak particle velocity (PPV) and understand instrumentation mounting locations to better interpret the readings provided following blasting operations. The Atlanta Airport is expanding the section of underground tunnels for its Plane Train people mover, and drill and blast operations were determined to be the suitable method of excavation for the project. Extensive work was done to begin creating prediction models and determining levels of concern based on readings from various types of instrumentation. This paper analyzes the effect of close quarters construction blast vibrations and observed frequency spectrum on existing structures with data from 22 different seismographs mounted in various locations and ground conditions.

Dec 1, 2022

By H. Maleki

Roof falls continue to affect productivity and safety in U.S. coal mines in spite of significant increases in support utilization in recent decades. To minimize roof stability problems while controlling support effectiveness, the U.S. Bureau of Mines is conducting research on support and ground monitoring techniques. Practical implementation of this research is presented in this paper. Instruments to monitor rock mass deformation, support loads, and microseismic emissions have traditionally been used to assess roof stability. Controlled-source seismic surveys are being used as well. In this paper, measurement techniques are reviewed, and the effectiveness of deformation measurements is demonstrated. This is achieved by an analysis of deformation history from four case studies in room-and-pillar retreat mines. In spite of differences in geologic, geometric, and support conditions in these mines, roof behavior is shown to have been similar prior to failure. The rate of roof movement is suggested as a reliable indicator of roof stability.

Jan 1, 1993

By S. J. Aresco

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grindability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instruction3 issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor; if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1969

By Deborah A. Peacock

"Outer space technology and exploration have reached a tipping point, so that mining and mineral processing in outer space is now a certainty and not a dream. Several competing companies worldwide are on the way to building spaceships to land on the Moon and eventually mine the Moon and asteroids for volatiles, rare earth metals and Helium-3.The Google Lunar XPrize offers a $30 million prize1. China has recently landed a spacecraft on the Moon. The European Space Agency, with cooperation from the United States, has landed a spacecraft, Philae, on a comet. And, Mars One is planning a one-way trip to establish a settlement of humans on Mars.How and why are the Moon and asteroids and their resources of interest to private space industry companies? Why are the Moon and asteroids viewed as a potential business venue?Geology of the Moon and asteroids — Why do we want to mine there?Space enterprises are actively working toward establishing and operating lunar and asteroid mining locations for resource extraction, resource processing, conversion to salable products and distribution of the products and services in space and to Earth and beyond2.Forty-five years ago, the Apollo manned missions to the Moon returned rocks and regolith to Earth, which were studied and analyzed. What they found was that the Moon contains valuable minerals and resources. These minerals are largely due to meteor and asteroid impacts, which have, over eons, created this mineral-rich regolith. These impacts have occurred on Earth as well, for billions of years, particularly early on in the history of the solar system. However, on Earth, wind, water and vegetation have erased most of these impacts. On the Moon, in contrast, the only weathering is caused by subsequent impacts and the solar wind."

Jan 1, 2017

By Joshua Hoffman, Catherine Johnson, Braden Lusk

Blasting conducted in surface coal mining operations in the Appalachian region consumes a significant amount of blasting agents. Emission of oxides of nitrogen (NOx) from these operations potentially represents an environmental challenge. This paper presents work conducted to quantify NOx output from the detonation of blasting agents common to surface blasting operations in surface coal mines. Annual ANFO and emulsion consumption data was collected from an operational surface coal mine located in West Virginia. It is known that many factors contribute to the types of gaseous byproducts released from the detonation of explosives. These factors include but are not limited to: fuel to oxygenator ratio, degree of confinement, and contamination. While, past research has been conducted to study the relationships these factors play on the release of NOx, these findings do not agree with one another. The annual explosive consumption values from the West Virginian mine were applied to NOx emission conversion factors in published literature. This lead to a range of NOx emissions from 95 to 914 tons in a year. Given the wide range of NOx production the utility of this information is suspect. The EPA recognizes a standard factor of 17 lbs (NOx)/ton (ANFO) however this factor is based on chemical composition and does not address contamination, confinement, or AN to FO ratio. This factor when applied to the West Virginia Mine's explosive consumption produced a value of 215 tons of NOx. There is a lack of information on NOx emission from emulsion type explosives. The work presented in this paper can be used by blasting professionals to quantify NOx emissions and guide future work for producing better predictor factors.

Jan 1, 2014

By J. B. Gayle

This investigation was conducted by the Federal Bureau of Mines to compare the selectivities of diverse flotation reagents and also of flotation and float-sink methods of separation. Flotation tests, using sodium chloride, an alcohol-type frothing agent, and a kerosine-pine oil mixture as reagents, were made on seven coking-coal samples representing four different beds. The results indicated equivalent selectivities relative to sulfur rejection when entrapment effects were minimized by recleaning the various products. Selectivities relative to ash rejection were also equivalent for some coals; for others, the selectivities of the reagents tended to increase in the order sodium chloride, alcohol-type frother, and kerosine-pine oil. Float-sink tests on these same coals generally gave results indicating better selectivities than those obtained in flotation tests at comparable levels of recovery.

Jan 1, 1960

By M. Frenzel, D. Ebert, K. Bachmann, A. D. Renno, R. Möckel, J. Gutzmer, J. Krause

With the increasing demand for metalliferous and mineral raw materials and the consequent depletion of the global natural resource base, the possible utilization of secondary raw material sources is receiving more and more attention. In the present study, we present results from a detailed vanadium deportment study of three basic oxygen furnace slag (BOS) samples known to containing elevated bulk concentrations of vanadium. Complementary analytical methods that were used to quantify the abundance and composition of V-containing phases include SEM-based automated mineralogy, X-ray fluorescence analysis, and X-ray powder diffraction as well as electron probe microanalysis. The vanadium deportment was quantified using Monte-Carlo simulations of the data obtained from automated mineralogy and electron microprobe analysis. The total V concentrations identified by XRF are between 1.7 and 2.2 wt.% V. The most important hosts of vanadium are larnite-, brownmillerite- and portlandite-solid solutions. In two samples Ca carbonates also significantly contribute to the V deportment, while wuestite, lime, and native iron do not contribute significantly to the vanadium deportment. A thorough consistency check identifies considerable uncertainties in the density of the V-bearing phases as the most likely reason to explain remaining discrepancies between measured and calculated V values.

Oct 14, 2023

By M Zoorabadi, B Hebblewhite, S Saydam, W Timms

Based on the cubic law, the hydraulic aperture of rock discontinuities has the most significant effect on the hydraulic conductivity of jointed rocks. The hydraulic aperture of rock discontinuities is a stress-dependant parameter and reduces with increasing applied stress. Furthermore, the rock stress increases with increasing depth. Therefore, hydraulic aperture is a depth-dependant parameter. In this paper, new empirical equations are introduced to calculate the hydraulic aperture of rock discontinuities at different depths. These equations were developed on the basis of back analysis of compiled packer tests from different actual cases. They provide the capability to calculate range of variation and average hydraulic aperture when the orientation of discontinuity and field stress tensor are given. Furthermore, it is possible to calculate the hydraulic aperture of rock discontinuities when its value is given for another depth. A hydraulic aperture of 7.7?µm was calculated by this method, comparing well with a reported site value of 8.3?µm for rock discontinuities at the Stripa mine project at a depth of 385?m. These new equations can be used by analytical or numerical methods to estimate the hydraulic conductivity of jointed rocks.CITATION:Zoorabadi, M, Saydam, S, Timms, W and Hebblewhite, B, 2014. New empirical equations to estimate the hydraulic aperture of rock discontinuities at different depths, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 375–380 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By W. L. Falke

Procedures in which manganese compounds are reduced and the metal is volatilized and selectively condensed, a hitherto neglected area, were investigated. More than 95 percent of the manganese was recovered from high-melting-point ores whether vacuum volatilization or atmospheric pressure volatilization was used, but neither process is economically attractive under present price-cost conditions.

Jan 1, 1966

By Gustavo Queiroz Esteves

O objetivo deste trabalho foi avaliar a utilização de peneiras de alta frequência em circuitos de beneficiamento mineral. Foram testadas diferentes aberturas de telas (mm), taxa de alimentação (t/h) e percentual de sólidos para verificar a eficiência global de peneiramento na fração 0.15mm. Frações retidas nesta malha têm sido apontadas como críticas para a flotação, sobretudo flotação em colunas. O circuito clássico das usinas normalmente utiliza ciclones para classificação de partículas finas (

Aug 1, 2018

By Alireza Ayoubian, Richard Finno

The network of freight tunnels in Chicago consists of about 62 miles of horseshoeshaped tunnels constructed typically less than 50 feet below ground surface. These tunnels serve as repositories of much infrastructure and should remain serviceable. The tunnels are often impacted by adjacent excavations and the question arises as to the existing state of stress in the final liner. This paper discusses construction of these tunnels and presents the results of finite element analyses which were used to obtain ranges for axial forces and bending moments that have developed in the final liner of the freight tunnels since their construction.

Jun 13, 2023

By Paul Downing

Anyone in business today knows how difficult and time consuming it is to keep abreast of new and revised federal regulations. Those in the explosives industry know that such a task can be next to impossible as the regulatory environment faced by those in the hazardous materials community continues to undergo a major overhaul following the events of September 11th, 2001. This paper will attempt to clarify today’s regulatory picture by identifying some of the regulatory “hotspots” and “pitfalls” that affect individuals and companies involved in the sale, transportation, distribution and use of explosives.

Jan 1, 2003

By A. Haile, A. Poole

During 2001-2002, the Granny Smith Mine of Western Australia undertook the development of a planned circular failure. Excavation took place in an interim pit wall that intersected the transported sediments, lake clays, and palaeo channel sands that overlay the deposit. The purpose of the study was to refine feasibility level slope parameters used for the initial design of the Wallaby pit, with the intent of increasing the overall slope when excavating the ultimate pit limits. During excavation, the geological and hydrogeological characteristics were studied in detail and data was collected using area-specific instrumentation and monitoring. Failure occurred in mid February 2002, at which time a detailed survey of the excavated slope using laser technology was conducted to provide geometric information suitable for back analysis of the material shear strength. The slope failure and associated information was analysed by geotechnical consultants. The revised shear strength and hydrogeological parameters were then applied to design the final pit walls. The slope redesign provided a cost saving of approximately seven hundred thousand US dollars. Design, slope formation, back analysis, the geology of the clay units, the hydrological environment, planned infrastructure, management and safety issues, and the on-going slope performance of the final slope are discussed.

Jan 1, 2004

Steady increases in longwall production have required operators to apply greater quantities of ventilating air in an effort to control and dilute respirable dust. Significant increases in shearer speeds necessitate that longwall supports also be advanced at a faster rate. Both of these factors may contribute to overall respirable dust levels on the longwall face because as supports are lowered and advanced, broken material falling from the top of the canopy is entrained directly into the air stream. To address this issue, the Pittsburgh Research Laboratory collected respirable dust samples from four longwall faces to characterize shield-generated dust. This paper investigates the influence of air velocity and shield advance rates on respirable dust levels. Also discussed are engineering controls currently used to reduce shield dust and alternative controls being investigated by the National Institute for Occupational Safety and Health (NIOSH).

Jan 1, 2009