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By J. T. Crawford

THE purpose of this paper is to present some data and comparisons regarding three types of Rheolaveur plants washing bituminous coal from the Pittsburgh seam. It deals only with the sections that handle coarse coal. The Rheolaveur system consists of launders or troughs in which coal and its associated impurities are conveyed by water. The impurities, being heavier than the coal, settle toward the bottoms of the launders and are drawn off through specially designed openings called Rheo boxes. Fundamentally, each plant consists of straight-sided, flat-bottomed launders of varying width and length, each launder equipped with one or more Rheo boxes for the removal of high-gravity fractions of the feed that are undesirable in the cleaned coal. Each launder has at least two longitudinal sections, the first with a slope of from 1 1/2 to 4 in. per foot of length, called the classification section. The single-box launder has a classification section followed by a washing section ahead of the box. A two-box launder is a single-box launder followed by a washing section and a second box. The slope of the washing section between the first and second boxes is determined to some extent by tonnage. At the end of the classification section, which may vary from 8 to 15 ft. in length, the slope abruptly flattens out to a slope of from ½ to 1 in. per foot of length. This flatter section of the launder, called the washing section, may vary from a few feet, in a single-box launder, to 15 ft., in a two-box launder.

Jan 1, 1938

By A. H. Daane, B. J. Beaudry

The yttl-irtm-nickel system has been investigated by metallo-graphic, thermal ard X-ray methods. There are nine intermetal-lic compounds present: Y3Ni, Y3Ni,, YNi,, YNi,, Y,Ni,, YNi,, and Y,Nil, which rodergo peritectic decomposition and YNi and YNi, which melt congruently. There are eutectics at 34.8, 57.5 and 93.3 at pct Ni which melt at 805°, 950 and 1285 C, respectively. Crystallographic data are given for YNi, YNi,, YNi,, YNi5and Y,Ni,. The terminal solid solubility is low. In recent work by Fisher and Fullhart' in which yttrium crucibles to be used for containers of uranium-chromium eutectic were clad with a high nickel steel, a low melting phase formed where the yttrium was in contact with the steel. To investigate the cause of this phenomenon, Daane, et al. made a survey study of yttrium systems with chromium, manganese, iron, and nickel and found an 18 wt pct Ni (weight percent) alloy to melt at approximately 950°C. voge13 in a study of the systems of cerium, lanthanum, and praseodymium with nickel found six compounds of the same formula in each system, i.e., R3Ni, RNi, RNiz, RNi3, RNi4, and RNi5. Since there is a great similarity between yttrium and the rare earths, compound formation was likely to occur also in the yttrium-nickel system. voge13 observed that the ability of transition metals to form compounds with the rare earths diminishes in the order nickel, cobalt, and iron while no compounds are formed with manganese, chromium, and titanium. Available data on yttrium systems with these elements indicate similar behavior, except that a slightly greater tendency toward compound formation is apparent. Simple eutectics with limited solid solubility have been found in the yttrium-titanium4 and yttrium-chromium5 systems, but at least one compound is present in the yttrium-manganese system.' In the case of yttrium-iron, at least three compounds are present,5 while only two are present in the cerium-iron,' and no compounds are present in the lanthanum-iron5 system. On the basis of both the trend in the alloying behavior of yttrium and rare-earth metals with the first transition series metals and the large number of compounds in the cerium-nickel system, one might expect six or more compounds to form in the nickel-yttrium system. A consideration of Hume-Rothery's rules of alloying based on size factor, electronegati-vity, and valence predicted low terminal solid solubility and possible compound formation. The present study was undertaken to confirm these predictions of

Jan 1, 1961

By Mitsuhiro Shibazki

I can't answer that question but I am looking at Andy, my co-author, and he says we didn't measure it. No movement. If I understand it correctly, how do we handle lateral forces in shear? The main columns were designed as pin connections so there wasn't a moment in the shear between the pile cap and the columns the steel reinforcing was used to resist that. I am not aware of how we would have installed those, it is possible to try and submerge them all if the jet grout is still fluid. They were higher than design. You are correct.

Feb 10, 2003

By Shuangsuo Yang

Coal ribs can roughly be divided into three types: (1) roof and floor rocks are similar to ribs, (2) roof and floor rocks are stronger than ribs, and (3) roof and floor rocks are weaker than ribs. Different types of roof/floor and ribs will exhibit different types of ground pressure around an entry. Most coal mines belong to the 2" type with ribs fractured or even broken. In this case the mine ground pressure depends on the occurrence and development of deformation and fracture of the ribs. If it's not properly controlled, the following deteriorating process will follow: the roof bent downward > the ribs squeezed and broken > rib sloughing and collapse > rib support to the roof reduced > the roof bent downward further > the ribs broken further. In this paper rib instability is divided into four types: compression/shear sliding rib fall, gravity sliding rib fall, cross arch rib fall, and cleavage rib fall. Since failure in thin walls is largely of tension type whereas that of thick walls by compression or shear, a concept is proposed here to utilize a thick bolted rib to stabilize entry ribs, i.e. the thickness to height ratio of the thick bolted ribs

Jan 1, 2005

By Zuomei Jin

The Mineralogical form of Silver in a Ag-rich complex ore was determined. In the complex sulfide ore, acidic thiourea leaching resulted in 35% extraction of silver directly. In the same complex sulfide ore, under the effect of ultrasonic treatment, 65% of silver can be ex¬tracted. After the above ore had been roasted and acidically leached of Zn and Cu, the silver extracted from this Pb-Ag residue was 96.8%. The effets of temperature, thiourea and ferric ion concentrations and partical size were examined. The leaching rate of silver from the Pb-Ag residue was diffusion controlled. The activation energy was calculated to be 10. 49%KJ/mole. The kinetic model for the thiourea leaching of silver from Pb-Ag residue was obtained and is given by, The kinetics of silver cementation by aluminium in thiourea solutions was also investigated. The activation energy was calculated to be 65. 13KJ/mole, which is reasonable fora rate-limiting surface reaction.

Jan 1, 1995

By M. Tanaka, Y. Sato, H. Narita, S. Alam, T. Ogata

To ensure a stable supply of rare earth elements (REEs), it is highly necessary to establish the corresponding recycling technologies for RE magnets and phosphors in inplant wastes and endoflife products. Solvent extraction using 2ethylhexylphosphonic acid mono2ethylhexyl ester (EHPNA) is often applied in the separation and purification of REEs. In this study, the equilibrium distribution ratios of neodymium and dysprosium between 1 mol/L nitrate solution and the EHPNA in an alkane diluent were measured at 298K. The experimental data were analyzed by correcting the nonideal behavior of the organic phase using the Alstad empirical equation under the assumption that a complex with a molar ratio of 1:6 (REE:extractant monomer) was formed. The model correlated well with the experimental data and the extraction equilibrium constants were obtained. The extractant equilibrium constants obtained by this methodology would be useful in the design of REE recycling processes using solvent extraction.

Jan 1, 2014

By Nolan B. Aughenbaugh

Zoning and environmental restrictions on land usage now make open- pit quarrying more and more difficult, especially near urban areas. One option for quarry operators is to go underground for mineral production. While underground-mining costs are higher than those for open-cut work, there are several compensating advantages. In many cases it is possible to produce the same material underground without affecting land values, and the surface is preserved for industrial, residential, or agricultural purposes. Proper planning can yield underground sites which have great potential value for industrial plants, warehouses, or other business uses. It is essential to plan underground mineral extraction using a three-dimensional modular-room architectural concept to fully exploit secondary space utilization. Prior to the start of underground mining an operator must make a careful geological engineering study to deter- mine the suitability of the deposit and must prepare a plan for safe and economical mining for the purpose of converting to secondary usage.

Jan 1, 1974

By C. R. Fettke, Bela Hubbard

During the summer of 1916, while on a visit to the United States Agricultural Experiment Station at Mayaguez, Porto Rico, the writers were told by D. W. May, the director, that an occurrence of manganese ore had been reported from the mesa southeast of Mayaguez. A visit to the locality showed that the mesa is covered by a mantle of bright red soil resting upon serpentine. Here and there over its surface concretionary masses of limonite have been mashed out of this soil. These were apparently mistaken for manganese ore. On account of the similarity of this occurrence to the extensive iron deposits of northeastern Cuba, it was thought that a brief description based upon a two days'reconnaissance survey of the area mould be of scientific interest. Mayaguez is on the west coast of Porto Rico, at Mayaguez Bay, which is the third in importance of the harbors of the island. The city itself is about 3/4 mile inland on the low-lying plain at the mouth of the

Jan 1, 1920

By A. Griffiths, G. Vickell

"INTRODUCTIONA successful cyanide destruction process has to ensure environmental compliance at reasonable cost. That this is possible with hydrogen peroxide is shown by the fact that over twenty gold mines either already use H2O2 or intend to start using it within the next few months. About half of these mines are in Canada.This growth is remarkable, considering that the first treatment plant to use H2O2 for detoxifying cyanide was commissioned less than five years ago at Ok Tedi, in Papua New Guinea.Hydrogen peroxide is being applied to a wide range of situations, including:Treatment of CIP pulps; examples: Ok Tedi, PNG; Hope Brook, Nfld.Treatment of barren bleeds and filtrates; examples: Nickel Plate, B.C.; Puffy Lake, Man.Treatment of tailings pond discharge; examples: Detour Lake, Ont., Page Williams, Ont.Treatment of excess heap leach solution; examples: Hope Brook, Nfld; Gordex, NS.Treatment of barren heaps after heap leaching; examples: Alhambra, NV; Wharf Resources, S.D.Treatment of pond reclaim water to prevent either ""preg-robbing"" or depression of gold-bearing pyrite in a flotation step; example: Getchell, NV.Treatment of backfill to prevent possible groundwater contamination; example Hope Brook, Nfld.Treatment of tailings ponds to prevent bird kills; example: Paradise Peak, NV.""Emergency"" units to deal with unusual events such as freak storms or dam failures."

Jan 1, 1989

By Stuart K. Nicol, Malcolm D. Engel, Neville T. Moxon

Ion flotatir,n of gold is a process being developed to selectively float extremely dilute aurocyanide liquors using a novel surface active complexing agent. The principle of ion flotation is also applicable to a wide range of other metal-containing solutions. The market potential of the gold flotation process would be enhanced by the possible combination of the gold recovery capabilities with both cyanide recovery and metal removal. For example, recovery of copper cyanides from a return liquid strean1 would be a useful means of reducing operating costs and satisfying environmental pressures to treat tailings dams. Experimental work is described where samples of tailings solution from a far north Queensland gold mine were subjected to ion flotation to remove copper cyanide species from a clear recycle solution. The form in which these products was removed was of secondary importance compared to the need to produce a clean solution for use in the plant. Recovery of the anionic copper cyanide species was accomplished using a quaternary ammonium surfactant.

Jan 1, 1991

By G. G. Griswold, B. S. Morrow

The copper-bearing ores concentrated at the Anaconda plant of the Anaconda Copper Mining Go. are principally a mixture of copper and iron sulfides associated in a gangue consisting of quartz, lightly altered granite and feldspars, with sphalerite and galena and more rarely barite and hubnerite as accessory minerals. The predominant sulfide is pyrite. The copper minerals present are: chalcocite, bornite (erubescite), enargite, chalcopyrite, covellite, tetrahedrite and some tennantite. Normal concentrator practice removes a slime prior to ball-mill grinding. The deslimed ore is ground to approximately 10 per cent plus 65 mesh for flotation. Two selective flotation circuits are used, one for deslimed ore and one for slime. Microscopic studies of concentrator products disclose such an interlocking of copper minerals with pyrite that any material increase in concentrate grade entails additional grinding unless recovery is sacrificed to a considerable extent. During the latter part of 1931 and the early part of 1932 the problem of producing a high-grade concentrate (40 per cent Cu) with at least no

Jan 1, 1935

By David C. Byrne

PURPOSE: Evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. RESEARCH SUMMARY: The results of previous NIOSH research show that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and gender. Using hearing thresholds at 4,000 Hz as an indicator, coal miners experience hearing loss 2.5 to 3 times greater than would be expected for persons not exposed to occupational noise. At age 50, 90% of coal miners and 49% of metal/nonmetal miners were found to have a hearing impairment. In comparison, only 9% of a nonoccupationally exposed control group had a hearing impairment at age 50. There are numerous barriers to the prevention of hearing loss among miners. In an effort to overcome some of these obstacles, this work was initiated to evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. Experiments will involve analysis of this new technology under both laboratory and field conditions. Laboratory components will consist of controlled studies using an anthropometrically correct test fixture as well as human subjects to evaluate the adequacy/effectiveness of various hearing protective devices. Electroacoustical performance testing of new noise monitors will also be conducted in a laboratory setting. Subsequent field studies will determine the actual usefulness and practicality of the personal protective/monitoring equipment as used in different mining situations. It is anticipated that increased on-the-spot awareness of hazardous noise levels and the availability of better-suited hearing protectors will provide a degree of protection beyond what is currently attained in different mining environments. Therefore, the intent of this project is to identify and adapt new acoustical technologies and products that have a direct application to individual mine workers. With increased knowledge of these technological advances, a greater demand for similar devices will likely occur, which, in turn, will lead to a better understanding and awareness of hearing loss prevention methods throughout the mining community. The ultimate goal is for widespread integration of useful hearing loss prevention products and devices into the daily routines of miners

Jan 2, 2000

"Projections of demand for Alberta coal indicate a quadrupling of current production rates to some 70 million tonnes/year by the end of the century. About half of this output-comprised of subbituminous coal-will be required within the province, primarily for generation of electric energy. The remainder-roughly 70 per cent high-volatile bituminous (hvb) steam coal and 30 per cent medium- or low-volatile bituminous (mvb/lvb) metallurgical coal-will be exported, principally to Pacific Rim and Western European countries. Direct employment in mining and coal processing is projected to increase from the present ca. 3000 to at least 12,000 persons.This paper presents separate forecasts for subbituminous, hvb and mvb/lvb coal production in the period 1982-2000; notes a number of possible developments that could substantially modify these forecasts; and briefly discusses attendant infrastructure requirements. Attention is drawn to potential shortages of qualified manpower and to threatening inadequacies of transportation facilities.IntroductionDespite the dislocations triggered by the 1973 'oil crisis', energy budgets of Western industrial countries are mostly still in the very early stages of the anticipated transition to greater reliance on coal. Shift s to coal are still more often only talked about than being implemented; and the public policies which are essential for timely development of facilities for producing, transporting and using coal are in many instances not yet even broadly formulated, let alone enunciated.In these circumstances, long-range projections of coal demand and supply-even if restricted to internal requirements- are subject to greater uncertainties than usually afflict such forecasts.On the demand side of the equation, these uncertainties arise ultimately from linkages between a need for coal and the availability and pricing of OPEC oil. The current surplus of oil on world markets, which has recently forced substantial reductions of posted prices, is undoubtedly a transient phenomenon that is unlikely to have any long-term impact."

Jan 1, 1982

By Joseph W. Roe

MaNY questions arising in the work of the mining engineer may be solved quickly and with suffcient accuracy by the methods of descriptive geometry; but, unfortunately, this subject is more often considered from a mathematical view-point than as an effective tool for solving practical problems. Some of the principles involved are merged into the ordinary operations of mechanical drawing, and are used unconsciously by the engineer in his every-day work. The rest are stowed away on the book-shelf with his forgotten or rarely-used college text-books. One reason for this condition of " innocuous desuctude " may lie in the uifortunate and often cumbersome notation which it has been found necessary to introduce. If some of these principles can be recalled to the engineer's attenti011 in terms of' every-day use they may prove of practical hearing. Recently, in talking with several mining engineers, I used some of the drawing-room methods of a machine-designer, to the evident surprise of those around me. These men were perfectly familiar with the methods, but their application to mining-work had not occurred to them. At their suggestion the present paper is offered, not in ally way as a treatise, but merely to suggest a certain point of view, in hope that it may lead others far more familiar with mining-problems to pursue the subject further. I. To Find the Strike. As the simplest and most fundamental problem, let it be required to find the strike of a vein when the location and elevation of three points on the outcrop are known. It mill be assumed for the present that the rein is a plane.

Jan 1, 1911

By Valenta R. K

A technique is presented for the integrated forward modelling of the three-dimensional structure and the geophysical response of multiply deformed terrains. This technique allows information collected by field geologists and geophysicist to be reconciled by the development of a simplified kinematic structural history of the area. The structural modelling simulates the deformation history of the area in terms of a succession of structural events, such as folds, shear zones and intrusions. The interaction of these events with a starting stratigraphy results in the prediction of the geometry of the structures. By specifying geophysical rock properties for the units in the initial stratigraphy predictions are possible for the potential field anomalies for gravity and magnetics. This approach is suited to a range of applications, and its uses in the modelling of regional structures, testing of geophysical data processing, volume balancing, multiply constrained inversion and training are discussed.

Jan 1, 1995

By Walter L. Crow

MUCH has been published on highly technical phases of grinding. Very little has been written on how a mill man can improve his operations by determining the optimum size assortment of grinding balls that should be added as a makeup charge. This ball rationing is not to be confused with the ball ration used as an initial charge when the mill is started up. Ball rationing is considered for one or more of the following purposes: 1) to increase throughput of the mill, 2) to reduce the power required per ton of ore ground to the desired size, 3) to reduce steel consumption per ton of ore ground, 4) to improve product size, and 5) to lower retention time of ore in the mill.

Jan 7, 1957

Feasibility is a value improvement process for projects. At any stage in project development, a feasibility study can be undertaken, but although the scope generally remains unchanged the extent of detail and level of accuracy usually increases with time. The main scope elements are a business definition, project description and an execution plan. The studies are designed to assess the potential of the project and to secure funding for on-going examination. Invariably, the investigations loop back to earlier stages to establish more appropriate development criteria but a critical stage is reached when a project construction decision is requested. This feasibility study requires very detailed presentation and analysis to a higher accuracy for the owner(s) and their potential lender(s).

Jan 1, 1997

By D. M. Wyslouzil

"Micron or sub-micron size gold inclusions in sulphide minerals cannot be extracted by conventional cyanidation. The gold surfaces must first be exposed by decomposition of the sulphides. As an alternative to roasting, pressure oxidation was found to be a most satisfactory method to decompose the sulphides and expose the gold particles. For cyanidation the pressure oxidation pulp has to be neutralized and stabilized with lime. It was found that thiourea can extract the gold directly from the pressure oxidation pulp without pH adjustment and oxidant addition. The main obstacles against the common use of thiourea are circumvented by a recently described control method of the emf during leaching.INTRODUCTION Amalgamation and cyanidation are the most conventional processes for gold extraction. The prerequisite for gold extraction is the possibility of gold surface to be contacted by mercury or by the cyanide solution. Encapsulated gold has little chance of contact and this leads to poor extractions.The reasons why a gold ore may be refractory are: micron or sub-micron size gold particles included in the sulphide minerals, such as pyrite and arsenopyrite; presence of and association with antimony, arsenic, tellurium and carbonaceous minerals. Some alternative processes, such as double oxidation(1,2), pretreatment with lime , H202, chlorine and Caro's acid, roasting and thiourea leach, have solved some of the problems of ""refractory"", but the sub-micron gold in sulphide minerals still shows little response. Roasting and the cyanidation of the calcine was one of the most successful approaches for this type of gold ore.There are two disadvantages to the roasting process: (1) the generation of sulphur, arsenic, antimony and mercury containing gases is undesirable and the control is extremely expensive; (2) gold particles might be fused in the roasted product and the oxidized base metals in the calcine might reduce the cyanidation efficiency. In recent years the pressure oxidation process has been considered as one of the more effective and satisfactory methods to decompose the sulphide minerals and expose the gold surface to the cyanide leach solution. The pollution problem could be better controlled and the gold extraction is more amenable."

Jan 1, 1985

By D. W. Fuerstenau

Locked-cycle grinding experiments on mineral mixtures provide a means to study circuit performance in simulated continuous grinding systems. Such experiments with calcite/quartz mixtures revealed that approximately twenty-five 2-minute cycles are required before the composition of the circuit product and the recycle material attain steady state. The circulating load, after steadily increasing during the first 15 cycles, continued to fluctuate over a narrow range. Previous batch ball mill grinding of mineral mixtures has shown that breakage rate functions of minerals are time- independent but composition-dependent. In the closed-circuit grinding of ores with constituents having different grindabilities, the grinding rate parameters for the components also would therefore change during the transient period. With fluctuations in feed composition occurring randomly every half to one hour in processing plants, it is quite likely that the grinding circuit can be in unsteady state perpetually. The significance of these observations is discussed in this paper in the con- text of the models used in control schemes for the grinding circuits

Jan 1, 1984

By A. M. Johnson, M. M. Singh

The mechanism of failure under a drill bit is still improperly understood in spite of several investigations of the subject. Generally, the cratering process under static loading conditions is considered to be similar to that achieved dynamically by impact. This paper attempts to indicate that, although the sequence of fracturing in the two cases appear to be identical, at least some dissimilarities exist. For example, the width-to-depth ratios of the craters vary to some extent, and the amount of energy consumed per unit of volume of craters is unequal for the two different loading conditions. Prevalent rock penetration processes are dominated by methods utilizing mechanical attack on rock. It is, therefore, generally accepted that a better comprehension of the mechanism of rock failure under a wedge would prove beneficial towards improving present drilling techniques. Several attempts have been made in recent years to explain how craters are formed under a drill bit, but the mechanism of failure beneath a bit is still improperly understood. 1-11 Most investigators, to date, have inferred the sequence of events occurring during crater formation from analyses of force-time diagrams,1"6 from theoretical considerations,7 or from a study of the configurations of final craters.8-l0 These analyses have led to the presentation of widely divergent models for rock failure beneath a drill bit, ranging from brittle to viscoelastic. The cratering process under dynamic loading commonly is regarded as being similar to that obtained under gradually applied, or 'static', loads. But the effect of rate of loading on the action of a bit is still disputed. Some investigators11-12 maintain that there should be no such effects, whereas others have demonstrated experimentally that these exist.13-17' The purpose of the investigation reported in this paper was to examine petrographically the damage done to rock under the action of a chisel-shaped wedge, both with 'static' and dynamic loading, and to determine if rate-of-loading effects could be detected. Significant quantitative differences in crater volumes and depths were found to exist for a given consumption of energy. On the basis of this data, an attempt was made to indicate some of the rheological properties that a proposed model should possess. All the work reported herein was conducted at atmospheric pressures. EXPERIMENTAL APPARATUS AND PROCEDURE Two types of rocks were employed for most of the experiments reported in this paper, viz. Bedford (Indiana) limestone and Vermont marble. The mechanical properties of these rocks are given in Appendix A. Actually two types of Vermont marble were used, but since no marked difference could be discerned between the two varieties (as seen in Fig. 10) the data was used collectively for the analysis. Stronger rocks were not employed owing to difficulty in generation of observable craters without damage to the equipment. Six-in. diam cores were drilled from the rock samples and embedded in 8-in, diam steel pipe with 3/8-in. wall thickness, using hydrostone to fill the annulus between the core and the pipe. This procedure was adopted to confine the rock specimen so that fractures would not propagate to the edges of the cores. This goal was achieved satisfactorily for these tests because no cracks were observed to extend into the medium surrounding the rock, even when craters were formed only 1 in. from the rock core periphery. Three to four craters were formed on a core face, because the rock damage from any one crater generally did not appear to extend into the others. Whenever, interference between damaged areas around adjacent craters was suspected, the data was rejected for purposes of the analysis. The limestone and marble samples were tested with a 60-degree, wedge-shaped bit, 1 5/8-in. in length, made of tool steel. The bit shank had two SR-4 type electrical resistance strain gages, mounted axially, to record the force-time history during the loading operation. The static indentation tests were conducted using a 50-ton capacity press fitted with an adapter for drill bit attachment. See Fig. 1. The force exerted by the bit at any instant was measured with strain gages affixed to the bit shank. An aluminum cantilever, with two SR-4 strain gages mounted near its clamped end, was employed to measure bit displacement. Both sets of gages were included in Wheatstone bridge circuits,

Jan 1, 1968