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By Jeffrey C. Wynn

Since the early 1970's, the U.S. Geological Survey (USGS) has carried out exploration geophysical research on non-basemetal strategic mineral commodities, including uranium, lithium, gold, potash, and chromite. The chromite study (largely completed) and the potash study (still going on) carried out during the past 4 years have not been aimed at the discovery of new ore reserves, but instead were designed to complement exploration by private mining companies. The USGS has carried out research not normally conducted by these companies, but which can be used by them in their efforts to increase production of strategic minerals. Results of the chromite and potash studies highlight the importance of: 1) a laboratory-research phase (petrophysical and petrographic studies) at the beginning of work on any new commodity; 2) an operative or functional ore-deposition model to serve as a conceptual framework, and the necessity to continually test, refine, and modify it during the study; 3) indirect geologic/geochemical indicators, secondary associations, and the use of multiple physical properties; and 4) the use of a systematic inverse-cost sequential-exploration (i.e. lowest resolution and lowest cost first) strategy to keen the exploration economically reasonable. The keystone to the success of the study is frequent and substantive dialogue among geologists, geophysicists, and geochemists.

Jan 1, 1981

By W. A. Backofen, D. Lee

Titanium of commercial purity (RC-70) and two all-a (hcp) alloys (4Al-1/4O2 and 5Al-2.5Sn) were tested in sheet form under conditions of combined-stress loading. Plane-strain compression and plane -strain tension together with uniaxial compression and tension provided information for constructing the tension-tension and compression-compression quadvants of the plane-stress yield locus. Coordinate values were obtained from yield-strength measurements; the slope at each point was based on a plastic-strain ratio. The materials represented a wide range of plastic anisotropy, which was reflected in correspondingly varied departures of the yield locus from that for iso-tropy. The tension-tension and compression-compression quadrants were not identical. If the uniaxial yield strength is insensitive to direction and the sign of the applied stress, the Mises or perhaps the Tresca criterion is adequate for predicting the onset of yielding under combined-stress loading. The prediction is not so straightforward in plastically anisotropic material. Depending upon details of texture, combined-stress yielding resistance may be substantially different from that indicated by the usual criteria.' However. a continuum theory of yielding under such conditions is available for reasonably direct application.2,3 Whether or not it can be used successfully must, of course, depend upon how closely the conditions of the theory are satisfied in the material in question. In its present form the theory contains no provision for Bauschinger-type effects, nor does it allow for the consequences that might grow out of deformation by more than one mechanism, e.g., by slip and twinning.4 With those limitations, more importance must be attached to experimental information about the yield surface for anisotropic materials. Studies of the yield surface have generally been confined to states of plane stress (tension-tension and tension-compression) established in thin-wall tubes by externally applied forces and internal pressure. That approach would be entirely suitable for anisotropic materials if they were available in tube form or in sufficient bulk to be machined into test specimens. 6-9 It would not serve for the textured and anisotropic sheets of much current engineering interest, unless sheet could be formed into high-pressure tubing without structural change. Since there would seem to be little chance of the latter, practical alternatives are needed. One such alternative is the subject of this paper. It involves the use of a few selected but relatively simple uniaxial loading tests on sheet specimens. The underlying idea is presented here with some details relating to application and a few results bearing on how well it has worked. THE BASIS OF TESTING Conventional Measurements. Yielding for a general case of anisotropy is described by the plane-stress locus in Fig. 1. Reference directions in the sheet specimen are related to the stress coordinates as shown with the insert: x is the rolling direction, y the transverse direction, and z the through-thickness direction. The four reference-direction yield strengths (t, tension; c, compression), Xt, Xc, Yt, and Yc, are all different. Nine paths that can be followed in uniaxial loading experiments are identified. Paths 1, 2, 3, and 4 represent conventional tension and compression testing to establish Xt, Yt,.Xc, and Yc. Useful information also comes from the ratio of the transverse plastic-strain components associated with yielding and flow in conventional tension or compression. A condition to be satisfied in locus construction is that the plastic-strain vector be everywhere normal to the locus.10 The projection of the vector which would

Jan 1, 1967

By Qingxiang Huang

Shallow seam coal field has the largest coal reserve in China. Mining in shallow depth causes serious problems. One of them is subsurface dewatering. In this paper, the physical simulating model was performed to study overburden movement and aquiclude stability in the shallow seam mining of Yushuwan coal field, China. According to the characteristic of clay aquiclude in the overburden, the proper simulation materials and proportions of mixture for simulating the plastic clay aquiclude layers and brittle bedrock layers were determined by the stress-strain tests. The physical simulating model was carried out to simulate the failure and caving process of the roof and overburden. Based on the simulating tests, it was found that the movement of clay aquiclude follows the movement of the underlying bedrock layers. The basic caving mechanism of the overburden roof strata was also presented. The tests also showed that the best way to control the stability of aquiclude is to reduce the subsiding gradient Ts. This research provides a foundation for further study on mining dewatering and water conservation.

Jan 1, 2006

By Mario E. Rossi

The concept of entropy is classical in thermodynamics and information theory. Its potential use as a measure of the ordering of a spatial system is discussed. Although entropy has been discussed previously in the framework of spatial statistics and for univariate distributions, a bivariate data-based estimator has not until now been defined. Different statistical distributions maximize entropy, depending on the univariate, bivariate, or n-variate constraints applied. For bivariate distributions, with a known mean and known covariance, it can be shown that the distribution that maximizes the entropy of the system is the bivariate gaussian. A nonparametric bivariate entropy estimator is introduced, derived directly from the experimental cumulative frequency distribution. Assuming that this experimental bivariate distribution is representative of the population distribution, then a measure of departure from gaussianity can be introduced as a relative entropy estimator. Practical applications for the entropy estimator are discussed, and an example developed.

Jan 1, 1992

By Donald W. Gentry

In the mining industry, there are two widely accepted methods of determining the investment worth of a contemplated project. One of these is the payback method and the other is the more recent discounted cash flow (DCF) technique known as the internal rate of return. Both techniques can be useful, but it is important to know the assumptions and characteristics of each procedure and how these may affect an investment decision. The Payback Period-A Shortcut to Yes or No The payback period is simply the time it takes for the cash inflows from an investment to equal that investment. Understandably, projects with short payback periods are preferred to those with longer ones. The payback period may be measured either from the time the initial investment is made or from the time that it begins to yield positive cash flows, but the latter approach is more realistic because it permits more accurate allowance for lost interest on the invested capital.

Jan 1, 1971

By Christopher H. Clement

The International Commission on Radiological Protection (ICRP) is an independent, international organization that advances for the public benefit the science of radiological protection, in particular by providing recommendations and guidance on all aspects of protection against ionizing radiation. This presentation touches on aspects of The 2007 Recommendations of the ICRP, a fundamental document that lays out the system of radiological protection for all exposure situations and types, and focuses on other recent publications relevant to the uranium industry. Of particular relevance are the 2009 ICRP Statement on Radon and the accompanying report on lung cancer risk from radon.

Aug 1, 2010

By L. H. Adami

Heats of formation were obtained for four anhydrous crystalline sodium borates by hydrochloric acid solution calorimetry. The heats of formation at 298.15° K from the elements are NAB02, -233.2 ±0.6 kcal/mole; Na2B07, -786.4 ±1.0 kcal/mole; NaB305, -549.9 ±0.8 kcal/mole; and Na2B6013, -1,412.5 ±2.0 kcal/mole, The heats of formation from the constituent oxides are NaB02, -31.5 ±0.8 kcal/mole; Na2B407, -78.8 ±1.3 kcal/mole; NaB305, -44.1 ±0.8 kcal/mole; and Na2B8013, -96.7 ±1.5 kcal/mole.

Jan 1, 1968

By T. Guerin

More than 370 million litres of oil leak from hydraulic equipment every year, excluding all other sources of plant fluid losses. This item analyses the causes of fluid spills from plants and equipment on resource construction sites, and offers some possible solutions.

Apr 1, 2015

By H. R. Spedden, A. M. Gaudin, M. P. Corriveau

A preliminary study of silver ion adsorption by sphalerite in ion exchange column with influent electrolyte marked with radiosilver is described. Rapid ion exchange occurs at first followed by slow reaction controlled perhaps by solid state diffusion. One experiment with radiocopper instead of radiosilver is reported briefly. IT has been known for many years that sphalerite is floated after it has been activated by a metallic cation, particularly copper.' The activation of sphalerite by copper is known to be an exchange of an atom of copper for an atom of zinc at the surface of the sphalerite.2,3 It has been estimated from various guesses of the available mineral surface that the depth of the copper-bearing coating is of the order of thickness of one atom. However, the exact mechanism of the activation process is unknown. A number of metals other than copper act in the same general manner."' " In particular, it has been known that silver replaces zinc at the surface of sphalerite. As copper is usually divalent, whereas silver is monovalent, it may well be assumed that there are differences, perhaps major differences, in the detailed scheme of activation by these two cations. Furthermore, since silver has unusual photoelectric properties and may be a contributor to the fluorescence of sphalerite, a study of its activating mechanism might open up some interesting avenues for exploring these other phenomena. The choice of silver as an activator of sphalerite was suggested also by the fact that its radioactive tracer, silver 110, is particularly convenient in that it has a long half-life and is energetic enough to permit counting through a counter window. The experimental technique selected, therefore, included the preparation of solutions of silver nitrate con- taining a proportion of active silver nitrate sufficient to give convenient counting data. In further considering the method to be used, a desirable choice seemed the use of batch experimentation in which a given solution was allowed to act on a certain lot of mineral for a given length of time at a given temperature, this period of mutual reaction being followed by analyses of the separated solid and solution. But an alternative method seemed more attractive. This is the method now so familiar to the users of ion-exchange resins, which was first made famous by the Russian chromatographer, Tswett.6-8 It consists in forming the mineral into a porous column through which the solution is allowed to flow at a constant rate. The usual method of allowing a batch of solid to react with solution is the equivalent of a single plate distillation operation while the chromatographic or ion-exchange column is a multiple-plate method—the multiplicity of the plates being represented by the reciprocal of the rate of flow of solution through the column. It seemed to us that the chromatographic method had such

Jan 1, 1952

By S. Svoronos, B. Moudgil, R. Stana, A. El-Midany

Due to their similar surface properties, it is not always easy to separate carbonate minerals from other salt type minerals by froth flotation. A particular example is the difficulty of separating dolomite impunities from phosphate minerals. Such challenging fundamental and practical problems have inspired several research efforts in various laboratories around the globe to find methods for economically removing the dolomite. However, a universal and cost effective process is not in commercial use. In this paper, a new process for separation of carbonate minerals (dolomite or calate) from other associated minerals is presented. Differential solubility of carbonates in slightly acidic solution is utilized to generate micro GO, bubbles at the carbonate mineral/ water interface. Particle (e.g., dolomite)/ bubble aggregates float to the surface leaving phosphate concentrate with low MgO content. Interestingly, up to 6.0 mm particles can be floated by such micro bubble/particle aggregates. Different sutface-active agents were tested to stabilize the bubbles. Results of these tests are presented and the mechanisms involved are discussed.

Jan 1, 2005

By R. A. McIvor, R. Levac

"The Stobie No. 7 shaft, 14 ft diameter, double- drum skip hoist, was installed at the INCO Limited Frood Stobie Complex in 1942. Figure 1 shows the hoist layout. The hoist was originally equipped with babbitted journal bearings on the main drum shaft and pinion gears. In 1990, the hoist was modernized with a new braking system, two new 2000 hp D.C. drive motors, a thyristor armature supply and a PLC control system. The new drive motors were connected to the drive pinion gears with a gear type flexible coupling. The pinion gear journal bearings were refitted during the refit in 1990 as the existing babbitted bearings showed signs of wear. The pinion gear journal bearings had always run warm and had external cooling applied during the warm summer months. Figure 2 shows the journal bearings on the pinion shaft. The skip hoist main bull gear and two pinion gears were replaced in 1997 because of cracked bull gear spokes. New drive couplings were installed on the pinion gears and the pinion journal bearings were modified to allow some self-aligning properties to try to reduce the heating and wear on the babbitt. The modifications did not significantly reduce the heating problems and a decision was made in the spring of 1998 to convert the bearings to self-aligning, anti-friction-type bearings.The traditional roller bearings used on double helical pinion drive gears in hoist applications has always been double-row spherical roller bearings due to their high load-carrying capacity and misalignment allowances.Unlike single helical gears, double helical arrangements do not exert axial thrust on the pinion gear bearings, therefore, both bearings in the pillow blocks must float easily with any pinion displacement. Drum misalignment, thrust bearing end play and a multitude of other influences causes continuous axial displacement of the pinions when in operation. This constant displacement or “hunting” of the pinion gear to maintain its centre on bull gear often exceeds the axial clearance limits of spherical roller bearings thus resulting in a continuous sliding motion of the bearing outer rings against the housing seats. With time, the housing fit eventually wears, creating an out-of-round condition for bearing housing (maximum allowable cylindricity tolerance is IT4/2). When this happens, the pillow block housings must be replaced or re-machined to specification. Premature bearing wear and overheating will occur if a housing out-of-round condition is encountered."

Jan 1, 2001

By Thomas E. Marshall, Gerald L. Finfinger

The Bureau of Mines has developed a practical methodology for deter- mining occluded gas contents of domal rock salt samples. The method, which is portable and field worthy, provides results in 5 min or less and does not require a laboratory environment or specially trained personnel to obtain meaningful results. The results can be used to identify gas-enriched zones, and thus may aid mine operators in production planning or ventilation design. The test method is based on the relationship between gas content and the acoustic response of salt samples as they are dissolved in water. The relationship is defined by an equation, and the results are repeat- able. The equation was derived by testing a series of rock salt samples collected from domal salt mines in Louisiana.

Jan 1, 1987

This report describes the results of a program to design, procure, install, and evaluate a multi-channel underground telephone system of modern design in the Sunshine Silver Mine near Wallace, Idaho. Although the evaluation portion of the program was deleted, this report contains a cost benefit analysis for such a system using estimates of operational data for the Sunshine Mine. The results show a centrally switched telephone system of conventional design with ruggedized phone enclosures and special environmentally sealed dial pads to be the most economical.

Jan 1, 1982

By B. R. Stewart

The exclusion of coal fly ash from regulation as a hazardous waste has led to increased interest in returning ash to the coalfields for co-disposal. A multi-year column study used coal refuse with high potential acidity (4% total-S), and two alkaline ashes in various bulk-blends. The unamended refuse acidified rapidly, producing acidic (pH 1.7) leachates, high in dissolved metals. Treatments blended with sufficiently high amounts (20 to 33%) of alkaline ash produced alkaline (PH >8.4) leachates with low metal levels, while lower ash blending rates acidified over time to produce metalliferous leachates. Examination of solid materials indicated that pyrite oxidation was occurring to some extent in all treatments. A regression equation (r = 0.95) was developed to estimate time to net acid release for mixtures of these materials. Ash alkalinity and refuse potential acidity must be balanced to insure water quality for co-disposal environments, or the ash materials should be isolated away from acidic drainage waters.

Jan 1, 1997

By d&apos, Kathleen J. Amico

THIS SUMMARY appears in Minerals Yearbook volumes I and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operatons at or near mines.

Jan 1, 1963

Although laterite ores already provide a significant proportion of the world's nickel and cobalt production it is anticipated that they will surpass sulphide ores as a source of nickel in the next century. The most recent period of greenfield nickel project construction was during the 1970s when it was notable that all of the eight new plants were based on treating laterite ores. This was because of the relatively large selection of available high grade laterite ore deposits amenable to cheap open cast mining and a paucity of high grade sulphide ore prospect alternatives. Of the three processing options for treating laterite ores: 1. smelting for the lower horizon saprolite ore, 2. ammonia; and 3. acid leach for the upper horizon limonite ore, smelting currently accounts for about 80 per cent of nickel production. In the future, as saprolite ore grades decline because of relatively high exploitation rates, the incentive to process the large untapped reserves of limonite ore will increase. The high cobalt content of limonite ore also makes it ideally suited to processing by a hydrometallurgical rather than smelting route. With only two exceptions, all saprolite smelting operations have a Class 2 nickel end product (largely ferronickel) and do not produce a cobalt by-product. As a result of technological advances, the modified ammonia leach process for limonite and transition ore as undertaken at Yabulu, now allows the production of pure nickel metal as a Class 1 product, along with significant tonnages of cobalt by-product. The mixed Ni-Co sulphide intermediate product of the pressure acid leach processing of limonite ore at Mon is converted to Class 1 nickel and cobalt metal at Fort Saskatchewan, Canada.

Jan 1, 1996

By A. Dave Mackintosh

The Current demand for potash has pushed world prices to record levels and allowed Saskatchewan producers to operate at maximum capacity. Several years of strong demand has resulted in a permitting rush not seen since the 1960?s. Even though Saskatchewan has a huge potash resource, mining and processing constraints will limit the areas of economic development. Introduction In 1969 M. E. Holter prepared a report ?The Middle Devonian Prairie Evaporite of Saskatchewan?, published by the then Dept. of Mineral Resources. Holter?s report has remained the bible of geologists working in potash ever since. It is astounding that a report written before there was really much potash mining history in the province, is as valid today as when it was first published. This paper re-iterates much of Holter?s report and adds a little mining experience to essentially confirm the importance of his work.

May 1, 2008

By Charles B. Carpenter

[The Bureau of Mines selected Anahuac for a petroleum-engineering study because it is one of the notable fields of the Gulf Coast region. It is outstanding because the producing formation is very thick; ever modern technique of drilling' and development has been applied; complete records of all operations,, including detailed subsurface information have been kept; the field has ,been developed systematically; and every effort has been made to utilize the reservoir energy efficiently. Data and information pertaining to the development anal operation were collected, compiled, and studied by the writers as if the field were under single ownership. The chief aim of the study was to increase the accuracy of the existing methods of estimating reserves by applying all the data collected during the modern development of an oil field, These scientific aids include coring; electric logging; micropaleontology determinations of porosity, permeability of oil-bearing sands, and their connate water content; subsurface sampling of the reservoir oil; and depth-pressure measurements. Because the reservoir structure in the Anahuac field is extremely complex, special attention was given to methods of calculating the reservoir volume.]

Jan 1, 1941

By Erwin Stötzer, Renato Fiorotto, Wolfgang G. Brunner, Manfred Schöpf

"Deep mixing methods can be used economically for the construction of cut-off or excavation support walls where other systems such as traditional soldier beams and lagging walls would yie ld unsatisfactory performance, where the installation of vibrated or driven sheet piles could cause vibration induced settlements and where concrete diaphragm walls would be time consuming and expensive. The new CSM method can largely replace the more conventional single or multiple auger methods of soil mixing or jet grouting. The cutter tool is similar to a cutter used in diaphragm walls or cut-off walls and is operated with a Kelly mounted on a drill rig. With this system much deeper walls can be installed and even hard soil layers can be penetrated. CONVENTIONAL SOIL MIXINGIn 1962 Norman Liver patented an auger-based soil mixing technique that has become the basis for the world's current technology.The deep mixing method (DMM), as it is known today, is an in situ soil treatment and improvement technology where the soil is blended with binders and/or other materials that are introduced in a slurry or dry form.Typically one or more hollow, rotating mixing shafts tipped with some type of cutting tool are mounted vertically to the mast of a base carrier and are driven into the ground by hydraulic or electrically powered rotary heads. The shafts above the cutting tool may be further equipped with discontinuous auger flights and/or mixing paddles. The binder is injected through the hollow shafts to nozzles located near the cutting tool where it is mixed with the ground to form columns of treated soil.Individual column diameters range from 0,6m to 1,5m and may extend to 40 m in depth. They can be arranged individually or in contiguous or secant patterns to produce a wide range of treated soil structures on both land and marine projects. Typical configurations are: Single elements, rows of overlapping (secant) elements, grids, lattices and blocks (Fig. 1 )."

Jan 1, 2005

By T. B. S. Giddy

The advantages to be gained from the use of a high-density ion-exchange resin in a uranium recovery circuit are shown. It is concluded that, in existing fluidized-bed plants, the throughput of solution can be increased by up to 40 per cent at the same uranium recovery. Alternatively, the values in the barren solution can be improved at the same flow-rate of solution.

Jan 1, 1980