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By R. Gatzweiler

The Key Lake nickel-uranium deposits are situated within the Wollaston domain of the Churchill structural province. The host rocks of the two orebodies are of Aphebian and Helikian age. The orebodies occur mainly within a 5.2-km-Iong, northeast-trending zone which coincides with the intersection of the sub-Athabasca unconformity and a reverse fault striking east-northeast. The principal controls of mineralization are structural and lithostratigraphic (i.e., post-Athabasca faults, the sub-Athabasca unconformity and graphitic metapelites in the lower Aphebian, close to the Aphebian/Archean unconformity). Grades of up to 35% U3O8 and 20% Ni are recorded over intervals of up to 2 m. Some hypogene zonation exists and the nickel mineralization tends to underlie the high-grade uranium ore. The ore minerals include pitchblende, a-U307, coffinite, gersdorffite, millerite, niccolite, bravoite, zoisite, sericite, chlorite and kaolinite. The kaolinite is a post-ore, supergene alteration product. Chemical studies of the sub-Athabasca paleo weathering profile sho w that regolithization is characterized by depletion in Si02 and K20 and concomitant enrichment in Al203 and perhaps MgO. In the paleoweathering profile the ferromagnes ian minerals are chloritized, the Ksfeldspars sericitized and the plagioclase saussuritized. Preliminary geochronologic data from the ores reveal U/Pb ages of -1228 my, - 960 my and 89 my, and Rb /Sr data indicate basement ages of -1850 my and - 1372 my. Aphebian pelitic protoliths, carrying U and Ni, may have released some metals during post-Hudsonian weathering, and minor concentration in structural and geochemical traps may have taken place prior to the deposition of the Athabasca strata. However, it is felt that the bulk ofthe ore-grade mineralization wasgenerated after the deposition of the Athabasca formation and after faulting, probably during a major regional thermal/ intrusive episode of Grenvillian age. Several episodes of remobilization took place between 1228and 89 my ago.

Jan 1, 1979

By F. W. Bloecher, A. M. Gaudin

Using an adsorption-column technique the partition of dodecylamine between quartz and water has been determined at concentrations ranging from 0.5 to 4000 mg per liter. The adsorption varies as the square root of the concentration. Attachment of dodecylamine to quartz is reversible. The amount adsorbed in a flotation operation giving almost complete recovery is under 5 pct of the amount required for a monolayer.

Jan 4, 1950

By M Wilkes, C-Q Liu

Microbial oxidation of refractory sulphide ores (particularly gold and copper ores) are well-established techniques that are increasingly employed because of their low capital and operating costs and environmental benefits. CSIRO has established a multidivisional project, the æBioMineral Processing InitiativeÆ, with the goal of generating new and improved high temperature micro-organisms for biological oxidation of these refractory ores. The project is currently focused on the discovery/generation of novel hyperthermophiles for the bioleaching of copper from chalcopyrite. As part of this project we are investigating the practicalities of genetic modification of iron/sulphur oxidising micro-organisms. The molecular biology of iron/sulphur oxidising acidophiles is still in its infancy. This work is aimed at improving our knowledge of vectors, promoters, selectable markers, gene transfer and expression in these organisms. The Acidithiobacillus ferrooxidans genome is currently available and genomics is proceeding at a rate where in the next few years we can expect at least one or two relevant microbial genomes to be sequenced each year. New genes that impart useful characteristics to iron/sulphur oxidising acidophiles will be available from published genomes and the study of newly isolated hyperthermophiles. We need to be in a position to clone and express those genes. This paper will describe the isolation, transfer and expression of thiocyanate hydrolase genes in Escherichia coli and At. ferrooxidans. Most common antibiotics are not effective against iron/sulphur oxidising acidophiles. Also, the use of antibiotics or their resistance markers outside of a laboratory setting would not be appropriate. Resistance to thiocyanate should be a useful selectable marker, without implications for human or animal health. Additionally, thiocyanate resistant iron/sulphur oxidising acidophiles might have application in gold bio-oxidation plants in arid areas where reuse of contaminated tailings water is desirable. The cloning of thiocyanate genes in broad host range plasmids under the control of E. coli and At. ferrooxidans promoters and the expression and phenotypic effects in both species will be described.

Jan 1, 2002

By R. Thiessen

The question whether the kind, rank and grade of coal is in any way determined by the kind or type of plant from which it originated has been a problem since coal was first studied. Some investigators claim that the kind of plants has contributed none of the attributes that characterize the differences found in the various coals; others claim that all differences are caused by the contributing plant; and others hold that only a few characteristics are inherited from the kind of plant from which the coal originated. Most coalologists, however, give this matter no thought. It can easily be shown that the kind of plant which contributed to a coal had a marked influence on its kind and type. A number of factors enter into this problem, and all unrelated ones must be carefully eliminated, including metamorphism caused by the pressure of the cover, earth movements, mountain building and higher temperature. Only the fundamental substance—the plants out of which coal was formed—• and the causative conditions that gave rise to a peat swamp and the conditions imposed upon the plant and the plant substances during the formation of the peat swamp can be considered. Everything else being equal, the question then is, how far do different classes and types of coal owe their differences to different kinds or types of plants? Geologic Age of Coal Coal has been laid down in almost every geological period since the Devonian era. Even as early as the middle Devonian some coal was formed; although of no value it has great scientific significance. The most valuable coal was deposited during the Carboniferous. The coals of England were formed during the Mississippian, and most of the valuable coals of America, Europe and China during the Mississippian and chiefly the Pennsylvanian. From the Permian come the coals of France, Saxony, Thuringia and Schwarzwald in Germany and of Bohemia and of the Ural districts of Russia. From the Mesozoic come the coals

Jan 1, 1930

By P. R. Thomas

This paper addresses the relative long-term cost and resource position of new and existing ferrochromium production in selected Market Economy Countries (MEC'S). The market impact of new ferrochromium production in nations such as India and the Philippines and the continuing change in international trading patterns are also evaluated. This paper draws upon the data and analyses of a recent Bureau of Mines, Department of Interior, Minerals Availability Program appraisal that evaluated the cost and availability of chromite and ferrochromium production from the demonstrated resources of 80 producing or potential mining operations in 10 market economy countries.

Jan 1, 1984

By Warren D. Longwill

The Bureau of Mines inventoried Federal lands in the State of Oregon and classified them in detail, section by section, according to their availability for mineral exploration and development as affected by legal status and agency management practices. The Bureau determined areas of the State having past mineral production and/or known metallic mineral resources and areas favorable for coal, oil, gas, and geothermal resources, and prepared maps that spatially compare the availability of Federal mineral land with these mineral areas to demonstrate the extent of restrictions to mineral entry. Oregon contains 62.1 million acres, of which 33.9 million acres or 55% is Federal mineral land. About 2.3 million acres of Federal land is favorable for selected metallic mineral deposits, of which 64% is available, 13% is restricted, and 23% is unavailable. Of the 21.1 million acres of Federal leasable land favorable for oil and gas, 68% is available, 11 % is restricted, and 21 % is unavailable. Of the 146,720 acres favorable for coal, approximately 71% is available, 13% is restricted, and 16% is unavailable. Federal leasable land favorable for geothermal resources amounts to 458,968 acres, of which 42% is available, 34% is restricted, and 24% is unavailable.

Jan 1, 1988

By M. A. Chandler, G. T. Adel, J. N. Richardson, E. C. Gutierrez

A rapid, bench-top analyzer has been developed to determine P2O5 content and CaO/P2O5 ratio in phosphate ores. The analyzer utilizes a portable computer equipped with a frame grabber to measure the reflective intensity (gray level) of phosphate samples placed in front of a television camera. P2O5 content is related to the average gray level of the sample, while CaO/P2O5 ratio is determined from the amount of bright material present. The sensor is currently being used to analyze flotation concentrate samples at Texasgulf's phosphate operation near Aurora, North Carolina. Sensor development along with results from laboratory and in-plant testing are discussed.

Jan 1, 1993

By R. J. Watson

In an earlier paper, Ehrenburg and Watson1 published the develop ment for a potential function by which it is possible to obtain the electric potential at points on the surface of the ground when a current I passes between two electrodes and the subsoil is composed of parallel, homogeneous layers. In view of the continued interest in the resistivity method of electrical prospecting, the author has considered it desirable to publish the results of a number of theoretical studies making use of this potential function, and also the results of a considerable number of tests with models designed to show the soundness of the mathematical theory. It is hoped that these results will prove how erroneous the various empirical rules for depth determination may be. It has always seemed puzzling to the author that one can find, in papers published comparatively recently, statements upholding empirical rules for depth determination, and attributing most of the irregularities of resistivity curves to vertical discontinuities in resistivity in the subsoil. It would indeed be fortunate for the geophysical investigator if such a simple rule held. However, numerous investigators have proved both theoretically and by the success of their field work that such a rule does not hold, even by a "rough approximation" in many cases. On the other hand, as is shown in the development to follow, if the underground conditions are favorable it is possible for such empirical rules to give a satisfactory depth determination. Authors should be more careful about making such sweeping statements about the accuracy of these empirical rules because the relative simplicity of the field work places the method in the hands of any interested experimenter, and he is likely to become completely disgusted with the method after he has made several obviously wrong interpretations by empirical rules. There are simple and rapid methods for finding out whether the ground beneath the electrodes is sufficiently similar to the conditions

Jan 1, 1934

By L Soares, W T. Hennies, F Fujimura

A methodology of environmental performance evaluation in mining developments is proposed, as well as guidelines and procedures for obtaining information to improve their environmental performance. Environmental performance is the results of the mining activities and their relation to environmental issues. If this evaluation is carried out on an on-going basis, it is possible to anticipate or to identify the formation and development of an environmental impact in its early stages. Evidence or trends identified by environmental evaluation provide valuable information to prevent further damage. The proposed methodology is based on the significant environmental aspects of a selected monitored job site by environmental indicators which are then compared with previously defined environmental criteria and targets or goals. The methodology procedures also take into account the environmental accounting of the investments and expenditures.

Jan 1, 2003

By Chester T. Sims

RECENTLY, a new type of superalloy material called TD Nickel* has been marketed.' It is a sim- ple, two-phased alloy, consisting of thoria particles dispersed in nickel of rather high purity (Ni-2 pct Thoz). Its mechanical properties appear relatively superior to previous experimental material attempting to use the oxide nonmetallic dispersion concept (except SAP), and superior to conventional nickel-base alloys at high homologous temperatures. This is derived from an interesting method of creating the dispersion, arising during chemical processing of the nickel and thorium salts in solution while reducing the nickel to metal. An evaluation of the thoria phase was conducted at this laboratory. Material and Procedure. TD Nickel was made available, consisting of several inches of 0.470-in. rod, extruded at a ratio of 64: 1, straightened, and centerless ground. Property determinations on this rod by the supplier at 1800°F showed an ultimate tensile strength of 11,400 psi, yield strength of 9600 psi, and 6 pct elongation. Specimens were removed from the rod for as-extruded metallography, and two 1/2-in. lengths supported on high-purity Al2O9 bricks were placed in a laboratory muffle furnace for exposure at 2000° F. The furnace door was left cracked to allow a slight amount of circulation. One specimen was removed at 200 hr for examination; the other was left for 2000 hr. Metallography. The micro structures obtained for the three conditions of exposure are shown in Fig. 1. Elongation of the grain structure in the extrusion direction is readily evident. The grains appear to be up to 0.001 in. (0.003 cm) long, with a length/width ratio of about 10: 1. Allowing for modest local in-homogeneities in structure, no significant change in thoria particle size or nickel alloy grain size occurred during the 2000°F exposure. However, etching depth varies slightly from one specimen to another, changing the number of particles visible. The thoria dispersion appears to be in the order of 0.01 (min) to 0.5 (max) p diam. The minimum diameter is difficult to estimate at X10,000, and may be less. Interparticle spacing appears to be about 0.1 p. Etching effects can be seen, depending upon grain orientation. A cubic etch-pit pattern appears in certain grains, apparently when etching is started by an anodic particle of thoria, Fig. l(c). The cubic pattern appears related to crystallographic orientation, and is prominent when the [ l00 ] direction is perpendicular to the plane of polish. The grains which present a ridged appearance in the photograph appear to be oriented with the [110} direction perpendicular to the plane of polish. Analysis. The thoria particle size was measured by a line intercept method perpendicular to the extrusion direction. Only particle sizes measuring 0.001 in. at X10,000 or larger could be extimated. Within limits of experimental error, particle size distribution appears to be unaffected by exposure, Fig. 2. To check structural stability further, a grain-growth evaluation was made. The number of grain-boundary intersections was counted at X500 on each of several traces normal to the extrusion direction for each condition. It can be seen from Table I that grain diameter appears unchanged by the 2000°F exposure. The slightly finer grain diameter after 200 hr may be attributed to variations in grain size from area to area in the original extrusion. From the present rather limited study of Ni-2 Th on, it appears that: 1) for time-temperature exposure up to 2000 hr at 2000°F (Larsen-Miller parameter = 57, homologous temperature = 0.8) thoria particles of the size studied are highly thermally stable; they do not significantly react, agglomerate, or diffuse; and

Jan 1, 1963

By R. J. Batterham, P. W. Roller

Granulated sinter mixes of three iron ore types were prepared with a range of water contents in a laboratory investigation. The mean diameter of the granulated mixes and the void fraction of beds of the mixes were determined experimentally. Pressure drop measurements over a range of flow rates were made in a laboratory permeameter with pressure tappings at several depths in the bed. The Ergun equation was applied to the results to determine the shape factor of the granulated mixes. Pressure readings down the bed were used to estimate the local void fraction in the bed using the Ergun equation and the calculated granule shape factors. It was found that there was a decrease in void fraction with depth in the bed. The significance of this and the variation of shape factor values with the amount of water used for granulation is examined in relation to the strength of granules of the sinter mixes. The experimental and mathematical techniques presented may be useful in interpreting the behavior of the permeability of sinter beds after ignition.

Jan 1, 1986

By L. E. Jackson, E. W. Dean

One of the refining processes to which lubricating oils are frequently subjected effects a reduction in content of paraffin wax. The actual treatment usually involves chilling and filter pressing; the most important result accomplished from a commercial point of view is lowering of the ""cold test"" of the oil. The Bureau of Mines has recently had occasion to ascertain the effect of changes in paraffin wax content upon the viscosity of oil and has conducted a series of experiments described in the present report.Object of the present investigation:The Bureau of Mines has devised and is using a method for the analysis of crude petroleum* which includes determination of the viscosities of lubricating oil distillates. The Bureau method does not provide for preliminary removal of paraffin wax, and it has seemed advisable to determine whether this omission causes any important variation from the results that would be obtained through commercial refinery processing. It was also thought that the present tests, though limited in scope, might be of some practical value in indicating the general effect of paraffin content upon one of the most important properties of lubricating oil.Experimental procedureA five-gallon sample of Pennsylvania crude petroleum was distilled at atmospheric pressure until 50 per cent of the charge had been vaporized. Two liters of the residuum was distilled at a reduced pressure of 40 mm. (absolute) and cuts were separated that came over between the temperature limits of 250° to 275° C. (462° to 527° F.) and 275° to 300° C. (527° to 572° F.). The viscosities of these fractions were determined and they were subsequently subjected to treatment that removed successive percentages of paraffin wax. Viscosity temperature curves were determined for the oil obtained after each removal of wax.

May 1, 1921

By S. R. S. Sastri, G. V. Rao

Because the nickel contained in lateritic nickel ores does not occur in an identifiable mineral, it is generally accepted that these ores are not amenable to beneficiation. For this reason, such ores are either directly smelted or leached to extract the nickel. In this paper, a process for enriching the nickel content of the lateritic nickel-bearing chromite overburden, normally a waste material generated during chromite mining, is described. In this flotation process, a nickel preconcentrate containing >1.1% Ni was obtained from material containing as little as 0.36% nickel. An empirical relationship was developed to predict the grade of nickel that can be obtained.

Jan 1, 1997

By D Kepert, C Simpson, D Edwards

Channel iron deposits (CID) currently supply over 40 per cent of the seaborne iron ore trade out of the Hamersley Province. The two well documented producing systems (Robe and Marillana palaeochannels) were both discovered during early reconnaissance mapping principally by BHP Billiton (BHPB) and Geological Survey of Western Australia (GSWA) during the mid 1950s to early 1960s. Both crop out extensively over the majority of their length. Hot on the heels of Fortescue Metals Group 2004 - 2005 discovery of approximately 2.6 billion tonnes (Bt) of undercover iron ore mineralisation in the Chichester Range, the Fortescue Exploration Department turned its attention elsewhere throughout the Hamersley Province. Reappraisal and analysis of publicly available data and ground truthing of developing models led to the recognition of the Solomon palaeochannel system. Subsequent exploration defined a world-class Resource of some 1.9 Bt of iron ore mineralisation of which the great majority is buried CID. Apart from the Marillana CID system, the Solomon region is the only major CID with significant tonnes of sub two per cent alumina CID with over 500 Mt delineated to date. Exploration has also outlined significant supergene bedded and detrital iron ore mineralisation. Ongoing drilling is expected to increase the resource base both in terms of tonnes and confidence. This paper outlines the principal contributing factors which led to the discovery of the Solomon CID and compares its geology with the Robe and Marillana palaeochannel systems.

Jan 1, 2009

By H. R. Grau

NIOSH’s Pittsburgh Research Laboratory is currently involved in research to identify silica dust generation in underground metal/nonmetal mines. The ultimate goal of this research is to develop control technologies to reduce worker exposure to respirable silica dust. Commodities and job classifications with the highest silica dust exposure have been identified through analysis of the Mine Safety and Health Administration (MSHA) compliance dust sampling database. Dust surveys were conducted in an underground limestone and gold mine to investigate silica dust sources, generation levels, and controls being used. A summary of the mining operations, sampling procedures, resulting data, and suggested methods to improve the dust control will be provided.

By F. A. Jerabek, H. L. Hartman

This study presents results of investigations in a small model of segregation in discharged fill slurry, the quantity of solids escaping in the drain liquid, and the relationship of solids to slurry concentration and discharge rate. Compressibilities of fine fill material, in dry and wet states and individual size fractions, are compared. Two terms are frequently used in describing the hydraulic placement of fill material underground: hydraulic stowing is mostly associated with the underground flushing of coarse-sized fill material, such as coal washery refuse; while hydraulic backfilling refers to placement of small-sized fill material, e.g., sand or classified mill tailings, mainly in metal mines. Characteristically, in backfilling, only a few hours may elapse between the time the material is hoisted as ore and redeposited as fill underground. Hydraulic filling was first used about 100 years ago to control subsidence in coal mines. It was subsequently adopted in many mining operations all over the world, but its basic concepts have never been adequately studied and analyzed. This is not surprising, when one considers the number of variables involved in the hydraulic backfilling operation. Recently, much work has been done on the problems of transportation of slurries in pipes. Comparatively less research work has been done concerning the physical properties of fill material (compressibility, cementation, permeability, etc.). Very little work has been done on the problems of fill placing, distribution, and segregation of fill material discharged in the mine void. It is the purpose of this paper to explore two of the basic, lesser known aspects of filling: segregation and compressibility in discharged fill slurry. Difficulties in observing the behavior of hydraulic fill slurry during the pouring operation underground, and insufficient knowledge to conduct any kind of meaningful theoretical analysis, suggest experimental model studies. The tests described in the following sections were conducted in the Rock Mechanics Laboratory of the Department of Mining at Penn State.

Jan 1, 1965

By AIME AIME

THE autumn is the time that nearly all the special groups within the broad field of the Institute's activitives chose for their own special meetings. The big annual meeting in New York in February has its own special advantages, but to realize them involves sacrificing others. A meeting of a smaller group with the subjects brought up for discussion much more closely limited to a single field of interest has some advantages that a big general meeting cannot possibly have. And so the custom has gradually developed of having these smaller meetings in the autumn, at con¬venient places, so the men will not have to travel too far from the job to be present. Sometimes the meetings have for their field of interest a single phase of mineral technology, and are called divisional, and at other times they cover a diversity of topics that are locally important in that geographical area, and are then called regional meetings. Of the five meetings to be held this fall, four are divisional and one regional. Two of the divisional meetings are to be held in the same place at the same time, but with programs so arranged that they do not conflict.

Jan 1, 1930

By K. G. Sutterer, R. J. Sweigard, U. Graham, T. C. Hopkins

The prevalent use of coal combustion byproducts in engineering applications has been with Class C and Class F fly ash as admixtures in structural concrete. But, the use of fly ash and bottom ash byproducts from modern desulfurization processes is receiving increased attention. The University of Kentucky has been conducting research into civil- and mining-engineering applications of these products. The studies have included extensive investigation of the geomechanical behavior of the materials and the effect of mineralogy on this behavior. These studies indicate important mineralogical considerations in the selection of materials for a specific application and highlight the importance of quality control before and during usage on specific projects.

Jan 1, 1998

By M. E. Wadsworth

The region about the south shore of Lake Superior is to geologists one of the most interesting districts of the United States, embracing as it does, in a limited area, old crystalline rocks, together with forms that are almost in their original condition of a beach sand and mud. In this region was first established the base of the geological column, the Azoic (" without life") System of Foster and Whitney, or the Archæan (" the beginning ") of Dana. Overlying this system are found the sandstones and limestones of the Paleozoic (" ancient life "), and their associated lava-flows (Algonkian ?). These systems possess a strong economic interest, owing to the stores of iron in the Azoic and of copper in the Paleozoic or Eozoic of this district, which forms one of the most important mining regions in America. The geology of this section is so difficult and complicated that, in its general discussion, perhaps no proposition can be stated concerning any portion of it to which exceptions cannot be taken. Indeed, out of the general discussion of different points comes in time the truth, and various geologists, even now, are working over this region in the endeavor to arrive at some consensus, or at least to determine upon what points they can agree, and upon what points difference of opinion will have to exist between them at present, until further evidence can be obtained. The writer will endeavor to give in a brief form that which appears to him at present to be the most correct statement of the geological structure of the region, admitting that from time to time, as more complete evidence shall be obtained, he expects to change his views in the future, as he has done in the past, if that evidence shall cause him to believe that he has been mistaken.

Jan 1, 1898

Many industries base their decisions on the assaying of tiny analytical sub-samples. The problem is that most of the time several sampling and sub-sampling stages are required before the laboratory provides its ultimate assays using advanced chemical and physical methods of analysis. As long as each sampling and sub-sampling stage is the object of due diligence using the Theory of Sampling it is likely that the integrity of the sought after information has not been altered and the generated database is still capable to fulfil its informative mission. Unfortunately, more often than not, unawareness of the basic properties of heterogeneous materials combined with the unawareness of stringent requirements listed in the theory of sampling, lead to the conclusion that massive discrepancies may be observed between the expensive outcome of a long chain of sampling and analytical custody, and reality. There are no areas that are more vulnerable to such misfortune than sampling and assaying for trace amounts of constituents of interest in the environment, in high purity materials, in precious metals exploration, food chain, chemicals and pharmaceutical products. Without the preventive suggestions of the theory of sampling serious difficulties may arise when making Gaussian approximations or even log-normal manipulations in the subsequent interpretations. A complementary understanding of Poisson processes injected in the theory of sampling may greatly help the practitioner understand structural sampling problems and prevent unfortunate mistakes from being repeated over and over until a crisis is reached. This paper presents an overview of the theoretical, practical and economic difficulties often vastly underestimated in the search for quantifying trace amounts of valuable or unwelcome components.

Jan 1, 2009