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By Suresh K. Bhatt

This U.S. Bureau of Mines report reviews major developments in continuous haulage technology for underground coal mines. Haulage systems, both in use and under development, were investigated through a comprehensive literature search and visits to mines and manufacturers. The systems include flexible conveyor train, mobile conveyor, monorail bridge conveyor, multiple-unit continuous haulage, extensible, and belt turning systems. Strengths and weaknesses of the systems are assessed in light of their operating under remote control and their application to the computer-assisted continuous mining machine research being conducted by the Bureau. Through mining scenarios, candidate haulage systems are conceptualized to be consistent with the capabilities of the mining machine.

Jan 1, 1991

By SIMON TIMBILLAH

The chalcopyrite-molybdenite (Cu-Mo) flotation industry is increasingly turning to organic depressants as suitable replacements for inorganic reagents, such as NaHS, due to environmental and safety concerns as well as high consumption rates of the inorganic reagents. This presents an opportunity for improvements or design and synthesis of alternative reagents. Disodium carboxymethyl trithiocarbonate (Orfom® D8) depressant is an organic depressant with a carboxylate group on one end and a trithiocarbonate group at the other end. Fundamental results are shown regarding the interaction of the Orfom® D8 depressant in the bulk flotation of a Cu-Mo concentrate from an operating North American mine. Cyclic Voltammetry on pure copper and Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS) measurements on pure chalcopyrite with Orfom® D8 depressant treatment are also reported. Through such characterization techniques a potential adsorption mechanism of Orfom® D8 on the mineral surface was identified and its depressant characteristics in the Cu-Mo flotation systems explained.

By C. Q. Cupps, R. F. Zaffarano, J. Fry

Reservoir oil analyses from seven wells in the Greater Clareton area have been included in a study of the original characteristics of oil in the Newcastle sandstone reservoir . These data correlated with areal location of the wells show an increase of saturation pressure in a general north - south or downdip direction . The increase amounts to about 500 psi in more than 17 miles , which corresponds to a depth increase of about 1,600 feet . To facilitate application of the data to engineering analyses , average characteristics are given for arbitrary north and south divisions of the 22 - mile - long producing area . The downdip increase of saturation pressure is taken as evidence of updip diffusion of solution gas from a somewhat higher concentration at the bottom of the reservoir . This effect is opposite to that previously observed in two prominent high- relief reservoirs in the Rocky Mountain area . The increasingly greater saturation pressures southward or downdip in the Greater Clareton area suggest a continuing migration of fluids into the structure .

Jan 1, 1964

By R. S. C. Smart

Surface chemical factors, including the balance of hydrophobic (e.g. collectors) and hydrophilic (e.g. oxidation products, precipitates) species, are major control determinants in flotation rates of specific minerals and therefore grade and recovery. There are a number of challenges involved with the surface analysis of different mineral phases from process streams in a flotation facility. The first is to collect samples that are representative of the process and retain their surface chemistry prior to introduction into the instrument. The second challenge in studying the surface chemistry of specific minerals is to find reliable methods of mineral phase recognition. In surface analysis of mineral particles, confident mineral selection can be difficult with many multi-metal minerals and with precipitated, adsorbed, reacted and contaminant species in the outermost molecular layers. The third challenge is to provide a statistical surface analysis of multiple grains of the same mineral. Methods to achieve these aims are described. Principal component analysis (PCA) of ToF-SIMS data provides improvement in phase recognition, particle selection and associated variations in surface species. Specific examples from both lab and plant operations, demonstrate that this technique can be utilized to differentiate surface chemical factors promoting (hydrophobic species) or inhibiting (hydrophilic species) flotation. A study of copper ion transfer (inadvertent activation) from chalcopyrite to pyrite and sphalerite clearly identified a statistical difference in copper intensities between the sphalerite and pyrite phases corresponding to their flotation response. The PCA analysis applied to concentrate and tails samples collected from the Inco Matte Concentrator demonstrated extensive CuOH and NiOH transfer between chalcocite and heazlewoodite minerals. The statistical analysis has been able to identify mechanisms controlling recovery and selectivity. High intensity conditioning (HIC) tests in which sphalerite was separated from a complex sulfide ore gave a 5% increase in the overall Zn recovery. The PCA/ToF-SIMS statistical analysis revealed the discriminating depressant action of adherent aluminosilicate (gangue) fine particles and adsorbed ions on the surface of sphalerite grains. HIC conditioning resulted in the removal of these gangue fines improving surface collector attachment efficiency.

Jan 1, 2014

By Ted H. Eyde

Nearly 17 years ago a major producer of synthetic zeolites started an extensive exploration program for natural zeolite deposits which resulted in the discovery of over 170 occurrences in the western United States. A few years later several of the other producers and consumers of synthetic zeolites also started similar exploration programs. Since then, small quantities of natural zeolite minerals have been produced from at least 12 deposits in the United States. Of these the Bowie deposit, about 13 miles north of Bowie, Arizona, is the most important,having produced over 5,000 tons of vitric tuff zeolitically altered to the mineral chabazite and minor amounts of the minerals erionite and clinoptilolite. Mining Districts and Mineral Deposits of Arizona compiled by Charles A. Mardirosian, Consulting Geologist, estimates the value of the total production from the Bowie deposit at a very conservative $2,000,000. Unfortunately, none of the companies responsible for the discovery and the initial production of natural zeolites made any effort to develop the high volume, low cost applications of this unique mineral raw material. Instead, they developed only the high unit value uses to supplement their existing synthetic molecular sieve product lines. With the producers of synthetic zeolites thinking in pounds and not in tons, further development of natural zeolite deposits stagnated for over a decade.

Jan 1, 1974

of our good friends and fellow members: Patrick J. Quealy J. C. Roberts Gilbert Morton Sidney W. Farnham who left the world better for their having lived in it

Jan 1, 1930

By NORMAN D. FitzGkrald

IN 1942 the outstanding characteristic of the petroleum industry was the multiplicity of war-induced distortions in virtually every segment of the business. So devastating was the success of the Nazi submarine campaign along the shores of the western Atlantic and on transoceanic routes that within six months after our entry into the war petroleum rationing was necessary in the East Coast area. The conquest of the Netherlands Indies by the Japanese three months after the opening of the war in the Pacific cut off our normal sources of rubber, and in our first year of war nationwide rationing of gasoline had to be invoked to conserve rubber-borne transportation facilities. Meanwhile the oil industry faced the imperative necessity for rapid expansion in the output of aviation gasoline and later accepted the vast responsibility for developing a new industry. synthetic rubber manufacture. Probably no other essentially peacetime industry has been forced to make so many complicated adjustments, yet its response to its wartime obligations has been nothing short of dramatic.

Jan 1, 1943

By E. E. Maillot

In 1943, diamond drilling by the Bureau of Mines, comprising 11 holes which totaled 1,295.6 feet, showed that the pegmatite at Black Mountain consisted of shallow lenses in interbedded biotite-quartz-schist and impure quartzite. The average thickness of the pegmatite was 9.7 feet. Mineralization had a zonal arrangement. Beryl was most abundant near the footwall contact of the pegmatite. The average estimated beryl content of the pegmatite exposed at the surface was 0.81 percent, and the highest content of any pegmatite area was 1.75 percent. Other economic minerals were scrap mica, feldspar, spodumene, and lepidolite. Representative samples of the Black Mountain deposit failed to yield high-grade boryl concentrates by straight flotation owing to the presence of considerable spodumene. By employing heavy medium separation to remove the spodumene, 75.4 percent of the. BeO wan recovered in a flotation concentrate assaying 10.4 percent BeO.

Jan 1, 1949

By George B. Clark

THE " Munroe effect" of shaped explosive charges was discovered by Charles E. Munroe more than 50 years ago (in 1888), but it was not until World War II that it was put to any practical use. Both Allied and Axis armies used the principle effectively in bazooka projectiles, artillery projectiles and in fixed shaped charges. The first two were used primarily to combat tanks and other armor and the latter to assault pillboxes and other fixed concrete emplacements. Many engineers and others who saw the military application of the jet effect of shaped charges believed application would be possible in many industrial fields where blasting is used, such as mining and quarrying. Some work has already been done on the problem of making shaped charges applicable to mining operations. Experimentation conducted at the National Tunnel and Mines' was directed primarily along the lines of use of shaped charges for secondary blasting in connection with long-hole stoping methods. Experimentation initiated earlier and conducted by the author2 at the University of Utah on a more scientific basis was directed at revealing the basic principles of the functioning of shaped charges, as well as the feasibility of using them in mining operations after the principles of their operation had been clearly defined. It was found that: (I) a given design of charge required an optimum standoff to make it most effective, either in penetrating solid rock or steel (see Fig 3); (2) for a given design of charge there exists an optimum ratio of charge diameter to charge height above which the increase in effectiveness of the charge decreases rapidly (see Figs 4 and 5); (3) partial confinement has the effect of making charge performance much more consistent; (4) the higher power and higher velocity explosives tested are much more effective than relatively low-strength explosives; and (5) shaped charges may be adaptable to mining operations in secondary breakage and drilling blasting holes. Fig I is a diagrammatic sketch of the action of a shaped charge for two types of cavities, while Fig 2 shows the approximate manner in which the jets are believed to be formed when an explosive wave encounters the cavity, approaching it from the top. The experimentation already completed has laid the foundation for further research in the study of shaped charges. Standoff effects, effect of the strength of explosives and other features have been fairly well established. Such elements in the design of shaped charges as (I) geometry of cavity liners, (2) relative horizontal dimensions of explosive column, (3) effect of

Jan 1, 1947

By C. E. Smith, R. J. Inglis, M. I. Brittan, J. H. Schoeman

"AbstractA number of plant-scale cyanidation tests were carried out in an attempt to uncover the causes of fluctuations in gold recovery efficiency. Computer analysis of the results verified that the treatment of reclaimed waste rock material along with normal run-of-mine ore was having an adverse effect on metallurgical efficiency. Mineralogical examinations showed that the free gold particles in the dump material were heavily tarnished or coated (predominantly by hydrated iron oxide), accounting for the lower recoveries. The indications were that the effect could be counteracted somewhat by using higher than normal cyanide and lime reagent concentrations and adequate leaching times. Analysis of the results showed further that leach pulp density was an important operating parameter affecting extraction efficiency. A variable activation energy leaching model provided an extremely good characterization of individual batch leach runs.IntroductionFLUCTUATING METALLURGICAL EFFICIENCY at the gold concentrator of the S.A. Land and Exploration Company Limited (""Sallies"") prompted some plant-scale cyanide leach studies in an endeavour to uncover the causes of the variations in gold recovery."

Jan 1, 1977

By D. G. Krige

I read the paper “The jackknife approach” with interest. There appears to be a widespread misunderstanding of the kriging variance as a measure of the error variance of the kriged grade estimate of an ore block. Virtually all mineral deposits display skew frequency distributions and are subject to the well-known proportional effect. Thus, it is usual to find in an ore body, when subdivided a really into subpopulations, that the variances of the grades (or the total sills of the variograms) for the subpopulations will be correlated with the corresponding mean grades (usually linearly with the squares of the mean grades). Thus, the variogram will be stationary.

Jan 1, 1996

By Milton Camino

El presente texto describe los antecedentes geológicos del yacimiento orogénico El Gigante, el cual presenta una mineralización filoneana del tipo relleno de fracturas asociada a estructuras de un lineamiento principal NW-SE. posicionándose como una de las franjas metalogenéticas de oro más importantes de la región y del mundo. De forma que se busca difundir los últimos resultados de la exploración a través de los nuevos descubrimientos en profundidad y los nuevos sistemas de vetas al borde Este del Batolito De Pataz. Así como formular un modelo que integre geología, mineralogía, cronología y geoquímica del yacimiento El Gigante, que permita mejorar el entendimiento de los procesos de formación de los yacimientos orogénicos de la franja metalogenética de Pataz y oriente al descubrimiento de nuevos recursos minerales.

Oct 21, 2015

By Irving Wender

This report describes Bureau of Mines experiments and reviews the work of others on the exposure of coal and coal-derived products to gamma rays and some other types of radiation. Results are presented on tests of three bituminous coals and a lignite that had been pulverized to minus 200-mesh particles and exposed to 1,000 megaroentgens of gamma irradiation from spent-fuel elements of a nuclear reactor. Of about 20 chemical and physical tests in Bureau work, only mass spectrometry of gases evolved during vacuum pyrolysis of the coals to 450° C gave results indicating differences in the irradiated and unirradiated samples. Mass-spectral distribution curves for CO and CO2 evolution showed fewer irregularities (reversals of curvature) for irradiated coals; thus, mass spectrometry appears to be the most sensitive method for determining radio-induced changes in coal. It is concluded that coal is not significantly altered by gamma irradiation owing to the resistivity of its highly condensed ring structure. High-level gamma irradiation, therefore, is unlikely to prove advantageous in coal processing and utilization. Specially treated coals, because of resistivity of coal to radiation damage, may be useful as an absorbent in processing radioactive wastes.

Jan 1, 1968

By C. W. Owings

"Ventilation is one of the most important features of coal mining, and if a mine is exceptionally gassy it is often difficult to ventilate it in such a way as to make it safe. The general system of splitting the main air current so that two, three, or more sets of room entries are ventilated by the same current of air does not provide a safe method if non-permissible electrical equipment, such as cable-reel, crab-reel, or trolley locomotives are used on gathering haulage, or if open-type hoist or pump motors are used. The problem has been greatly simplified at the Crucible mine of the Crucible Fuel Co. at Crucible, Pennsylvania.The system is not only applicable to the room-and-pillar method of mining, but it may be adopted for any panel system of mining. There also appears to be a definite application in mechanized mining, where the rapid extraction often results in inadequate attention to ventilation and where the gassiness of the section generally increases because, as compared to hand loading, the methane has less time to drain off. The system to be described should commend itself to coal-mining men.ACKNOWLEDGMENTSThis investigation was made possible through the courtesy of H. J. Nelms, general superintendent. E. M. Marshall, safety inspector, E. G. Sauers, assistant superintendent, and Thomas Mark, mine foreman, assisted in the collection of information."

Sep 1, 1931

By X. Zhu, Chen. L., R. Guru, M. Peiravi, M. Mohanty, L. Ackah, B. Xu

"The overall goal of this study is to develop a suitable flow sheet to extract rare earth elements (REEs) from coal ash. A total of 14 coal samples of different ranks were examined for REE concentration, and an anthracite coal sample with the highest REE concentration of more than 700 ppm in the coal ash was selected for REE extraction tests. This paper reports on the results of the experimental program completed in the first part of the study, which included hightemperature leaching with nitric acid followed by solvent extraction tests using various organic extractants, namely, tributyl phosphate, Cyanex 572, di-(2-ethylhexyl)phosphoric acid (D2EHPA) and their combinations. A 4×2×2 experimental design was used to conduct a total of 32 high-temperature leaching tests by varying acid molarity at four levels, solids content at two levels and leaching time at two levels. The highest recovery rates of 90 percent for light rare earth elements (LREEs) and 94 percent for heavy rare earth elements (HREEs) were obtained from the optimum leaching test conditions while maintaining impurity recovery to the leachate at less than 40 percent. D2EHPA was found to be the best extractant in this solvent extraction test series, providing an REE recovery rate of nearly 99 percent.IntroductionGlobal demand for rare earth elements (REEs) and other strategic metals is increasing rapidly due to their use in a variety of advanced technological applications, with more than 100 kt of rare earth oxides used worldwide on an annual basis. The United States has less than 10 percent of the world reserves of REE mineral deposits, and in 2013 imported more than 60 percent of its rare earth oxides from other countries, mainly China (United States Geological Survey, 2017). China’s institution of export quotas has significantly reduced supply to the United States, raising the urgency of finding new ways of producing REEs and/ or substitutes. Coal combustion byproducts, which are usually discarded as waste materials, are known to contain REEs in low concentrations that could be extracted with a suitable process flow sheet. This may be a worthwhile route to pursue, considering the short supply of rare earth minerals and the abundance of coal ash in thousands of ash ponds in the United States. More than 110 Mt of coal combustion byproducts are produced annually in the process of satisfying the country’s need for electricity (American Coal Ash Association, 2016), and less than 50 percent of these byproducts are being successfully used in various applications, with the remainder dumped as waste materials in landfills and ash ponds."

Jan 1, 2017

By David E. Nicholas

Design of underground openings is becoming more critical as the mine deposits become lower in grade, initial investments increase, ore depth increases, additional safety regulations come into law, and increased ore recovery is required for conservation of minerals. Stability of these openings is dependent on the strength of the rock mass and the pre-mine stress field. The rock mass is composed of solid blocks of rock (rock sub- stance) and structural features (faults, joints, bedding, etc.). Methods of testing the rock mass strength are improving and be- coming more common, however it is difficult to justify the high cost of large scale testing for an initial mine design. An alternative to testing the rock mass is to measure the rock substance and the structural features separately, and then combine them to estimate the rock mass strength. The rock mass strength will vary depending on the orientation of the opening with respect to the structural features. The other factor affecting the stability of underground open- ings is the pre-mine stress field. Methods are available to measure "directly" the pre-mine stress in competent and relatively massive rock. These methods are costly to employ, therefore, they may not be justified in an initial study. The pre-mine stress field can be estimated based on the structural relationships formed from past tectonic events.

Jan 1, 1976

By W. W. Simpson

The Bureau of Mines conducted research to determine the effects of potassium trithiocarbonate (KTTC), a degradation product of potassium ethylxanthate (KEX), on flotation of chalcopyrite and molybdenite. Small amounts of KTTC were identified in fresh and aged solutions of KEX using thin-layer chromotography. Hallimond tube flotation tests on pure minerals showed that KTTC acts as a weak collector for chalcopyrite. Both KEX and KTTC tend to depress molybdenite, but the depression effect is easily overcome by addition of a small quantity of fuel oil. The results of the Hallimond tube tests were confirmed in batch flotation tests using a porphyry copper ore.

Jan 1, 1983

By Stewart R. Wallace

Members of the Society, it is a very great honor for me to be here today and to have the opportunity of telling you about some things that have been accumulating in the back of my mind for some time. Before attempting to do so, I should acknowledge my debt to the many people who are responsible for my presence here this afternoon. To do this properly, however, would consume much of my allotted time and I will therefore mention only two men, both of whom were directly involved in the discovery of the Henderson ore body. The first of these was Robert Henderson, now dead, who at the time the work was going on was vice president of Western Operations of the Climax Molybdenum Co. Truly, he provided the environment that permitted the exploration program to function effectively, and the deposit appropriately bears his name. The second man I meant to mention was resident geologist at Urad at the time of the Henderson discovery. I think I should explain right here that the Urad ore body and the Henderson ore body, although entirely separate, are closely related deposits, and that both are located at Red Mountain in Clear Creek County, Colo.

Jan 6, 1975

By Thomas Mucho, Anthony Iannacchione

This marks the 100th year that the aggregate industry has been served by a national association. Of all the accomplishments this longstanding relationship has achieved, there is probably none greater than the progress made, in worker safety. Perhaps the best way to measure this success is to examine injury trends in the aggregate miner population. For example, in the first half of the 20th [ ] century, 16 quarry mining disasters (a "disaster" is an incident with five or more fatalities) claimed 157 miners between 1909 and 1952. The largest of these was the disaster at the Sandts Eddy Limestone Quarry near Allentown, Pa., on March 26, 1942, where 31 miners died of asphyxiation by fumes/explosion. Thankfully, no mining disasters have occurred in the aggregate industry since 1952. It is these kinds of information that help us characterize improvements in aggregate worker safety over the last 100 years.

Jan 1, 2003

By Michael L. Ogilvie

The proportion of underground coal production as a percentage of overall Australian production has fallen in the last 10 years, with underground production remaining more or less static at about 53 Mt (58 million st). However, underground coal mining remains a viable industry in Australia, due to use of modern longwall mining systems. In 1993-1994, 26 longwalls were in operation, with total production exceeding 39 Mt/a (43 million stpy). Some of these longwalls achieve productivity levels approaching efficient opencut operations, and in some cases, they exceed them. These high-production longwall mines are not without problems when depth and distances from outcrop increase and the gas content of the seams approaches or exceeds critical limits. When gas content of a coal seam exceeds 6 m3/t (233 cu ft/st), gas flows into the mine may be sufficient to interrupt production from time to time.

Jan 1, 1995