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By A. D. Hammond

"INTRODUCTION Vanadium deposits in Arizona are distributed all across the state, from the rim of the Grand Canyon to the Tombstone mining district in the southeast corner of the state (Figure 1). The combined past production of vanadium from Arizona and New Mexico ranks second nationwide, after deposits in the Colorado Plateau In the northeast corner of the state, in the Carrizo Mountains and Monument Valley of Apache and Navajo Counties, vanadium was produced as a by-product of uranium in deposits of the Salt Wash and Shinarump members of the Morrison and Chinle formations, respectively. The production took place between 1943 and 1970. Another source of vanadium in Arizona occurs in vanadate deposits associated with supergene enrichment of base-metal vein and replacement deposits. The most important vanadate mineral is vanadinite, a chloro-vanadate of lead. Presently, there are no primary mines of vanadium in the United States. In 2012, a small production of vanadium pentaoxide (V2O5) was reported as a by-product of uranium at the White Mesa uranium mine in Utah1. This paper describes vanadate deposits in Arizona with emphasis in three districts, namely, the Mammoth, Globe-Miami and Banner districts.VANADIUM EPIGENETIC DEPOSITS: VANADATES Almost all vanadium epigenetic deposits occur as vanadates in oxidized zones of lead, zinc and copper veins and replacement deposits. Vanadinite, descloizite and mottramite are the most common minerals in vanadate deposits. Descloizite is a vanadate of lead, zinc and copper. Wulfenite, a molybdate of lead is also present. These minerals replace supergene base-metal minerals, form crusts on faces of open cavities, or are inter-grown with residual clays in pockets. The vanadium content in vanadate deposits is believed to have been leached from the country rock by ground-water and transported through porous rocks until precipitating as a relatively insoluble vanadium compound or until the solution evaporated. Precipitation was brought about by local concentrations of cations of divalent lead, zinc or copper. Lead is a constituent part of almost all of vanadate deposits and the vanadium pentaoxide (V2O5) content in vanadate minerals seems to have a direct correlation with the content of lead in the hypogene mineral. Vanadate deposits are restricted almost entirely to the oxidized parts of vein or replacement deposits. It is rare that oxidized zones extend past 100 ft from the surface. Vanadate deposits are largely restricted to tropical and temperate zones and regions of dry climate. Arizona and New Mexico have the largest concentration of vanadate deposits in North America."

Jan 1, 2015

By R. August Heindl

[A proposes process for recovering manganese from open-hearth steel-plant slogs is indicated by the flow diagram shown in figure 1. Investigation of the process, the laboratory development of which was reported previously,4/ was expanded to a larger scale. Mixtures of flush slags and limestone were proportioned to have molar [SiO2] ratios of 1.5 to 2.2 and were fired at temperatures up to 2,400° F. In an oxidizing atmosphere. This produced clinker consisting principally me various combinations of the oxides of manganese, iron, aluminum, and magnesium aloe with a dicalcium silicate phase containing the phosphorus. Some tests were made with a continuous sintering machine of the traveling-grate type, but a rotary kiln was the most satisfactory apparatus for this operation. Material was fed at 150 to 200 pounds per hour after first being agglomerated either on the sintering or else binder extruding and drying finely ground mixture of the sing, limestone, binder, and water. Tests with slag; from tree different source indicated overkill manganese recoveries of 65 to 80 percent by ammoniacal-ammonium-carbonate leaching.]

Jan 1, 1955

By Aixiang Wu, Minjie Zhang, Zhuen Ruan, Yiming Wang

This paper combines theoretical and experimental analysis to conduct relevant research to improve the accuracy of predicting paste yield stress by slump flow. The analytical model of slump flow for yield stress is derived based on a mini-cylindrical mold with a height-to-diameter ratio of 1. It shows that the dimensionless slump flow is a monotonic decreasing function of the dimensionless yield stress and is independent of the material type (specific gravity), which provides a theoretical basis for quantifying the rheological properties of paste with slump flow. Three different tailing-prepared pastes were tested for their slump flow and implemented rheological tests simultaneously. The yield stress is obtained based on the Bingham model fit, as the measured value of the yield stress is substituted into the derived theoretical model. The studied pastes yield stresses range from 34.78 to 524.08 Pa, with corresponding dimensionless slump flow of 3.43 to 1.09. The results showed that the calculated slump flows were generally greater than the measured values. The analysis showed that this was mainly due to the thixotropy of the paste, with minor deviations ranging from − 1.5 to 5.8% for the less thixotropic pasted prepared from tailing C. An approximate analytical solution for yield stress as a function of slump flow is obtained using Taylor’s formula. However, it is unsuitable for predicting the yield stress because the yield stress calculated by this function is much higher than the measured value. The empirical yield stress model was constructed and experimentally verified. The results show that the empirical formula has high accuracy and good generality. The deviation of the studied pastes is between − 15 and 5%, which provides a practical method for rapid and accurate prediction of paste yield stress in mine sites.

Jun 1, 2023

By S. Lohmeier, D. Gallhofer, B. G. Lottermoser

In Southern Africa, historic mining and mineral processing of base metal deposits have almost exclusively focussed on the extraction of major metals, leading to the loss of remaining valuable raw materials into tailings dumps and waste rock piles. At the Namib Pb–Zn mine (Erongo Region, Namibia), historic base metal tailings deposits are present as unreclaimed exposed waste piles. The tailings comprise silt- (fraction A: d50 = 25 to 48 μm) to sand-sized (fraction B: d50 = 86 to 185 μm; fraction C: d50 = 210 to 230 μm) material and contain major concentrations of base metals (Pb av. 1.15 mass%, Zn av. 3.20 mass%), S (av. 9.95 mass%), as well as lower values of other metals (Cu av. 490 μg/g, Cd av. 133 μg/g, Ag av. 22 μg/g), and critical elements like Sb (av. 14.7 μg/g) and In (14.3 μg/g). Former mineral processing only targeted the extraction of galena and sphalerite. As a consequence, qualitative mineralogical composition of the tailings is similar to that of the primary ore. Ca–Fe–Mg(–Mn) carbonates, quartz, micas, chlorite, minor graphite, magnetite, and rare parisite relate to the former host rock and gangue matrix, whereas Fe-rich sphalerite, galena, magnetite, pyrite with minor pyrrhotite, rare arsenopyrite, marcasite, cassiterite, and accessory scheelite are original constituents of the primary ore. Reprocessing of such a material would be challenging, but a mixed Pb–Zn concentrate enriched in Cd and Ag might be obtained. In future, possible reprocessing of Namib tailings and associated disposal of wastes into an appropriately designed repository would not only generate valuable metal commodities, but such activities would also eliminate a major metal pollution source from the local environment.

Sep 9, 2024

By Steve Babcock, Howard Perko

Since the development of the ICC-ES AC358 acceptance criteria, the use of helical piles as deep foundation solutions has grown in popularity and expansion of desired applications. With this has come a desire to use larger diameter shafts to support larger loads. Helical piles employ a unique method to predict performance by correlating the final installation torque to the ultimate load carrying capacity for both tension and compressive loads. This capacity-to-torque factor is commonly denoted as the ‘Kt’ factor. Previous publications from multiple authors have estimated the capacity-to-torque relationship both empirically and theoretically for helical piles.  Most of these prior studies focused on smaller shaft diameters from 1.5-inch square to 3.5-inch round.  Current trends have motivated the helical pile industry to utilize larger diameter pile shafts than are not well represented by the prior publications, including AC358. This paper presents an expanded body of empirical data comprised of full-scale load test results of helical piles with diameters ranging from 1.5 inches up to 18 inches. The curve fitting methods used to develop the AC358 equation are re-examined and offers an alternative that better fits the test data. The current methodology uses a simple exponential curve with a limit of zero as pile shaft diameter increases. This implies that at some point a helical pile’s diameter would become so large that it would have zero capacity, which is illogical. Utilizing a horizontal asymptote, other than zero, in the curve fitting analysis provides a better fit to the data.  The better fit increases to the capacity-to-torque ratio for larger diameter piles on the order of 15% to 30%.  Also, presented are some key insights that the authors offer for consideration in further development of this critical relationship.

Oct 7, 2024

By John Ralston, Rossen Sedev, Nicola Richards, Quinn Anthony, Geoffrey Reynolds

Derivatised 2,4-diketopyrimidine groups have been anchored to planar gold surfaces as self¬-assembled monolayers (SAMs) for chemical and photochemical studies. Three derivatives, 5-methyluracil (thymine), 5-trifluoromethyluracil and 5-nitrouracil, were chosen for the specific moiety present at position C-5, which can exert strong or weak inductive effects on the adjacent aromatic ring. The measured acidity constants decrease from 5-methyluracil to 5-nitrouracil as the inductive properties of the group at C-5 position increase. When grafted to the surface the acidity constants increase, albeit still adhering to the expected inductive trend. The functionality also exerts an influence on the surface wetting properties. Surface wettabilities indicate that the orientation of the pyrimidine groups at the surface occurs so that the C-5 position has a direct effect upon the surface chemistry. Upon dimerisation the surface contact angles increase signifi¬cantly. At pH 11 the contact angle changes reflect that the dimer has a higher pKa than the monomer. The monomer surface is deprotonated at this pH while the dimer surface is partially deprotonated, leading to changes in contact angle of up to 22 degrees. Large changes in contact angle were observed for 5-nitrouracil which were independent of surface charge and were appar¬ently due to conformational changes alone. Electrowetting of three fluoropolymer surfaces by electrolyte solutions was studied with the sessile drop method. The electrowetting curve (contact angle/potential) is analogous to the elec¬trocapillary curve (surface tension/potential) and may be described by a combination of the Young and Lippmann equations. We demonstrate that for some specific surfaces a systematic deviation occurs at positive potentials. This departure is attributed to double layer effects, namely the adsorption of hydroxide and halide anions. pH, ionic strength and polymer composi¬tion can all influence electrowetting behaviour.

Jan 1, 2003

By C. A. Stickels, C. M. Yen

Secondary recrystallization was investigated in vacuum-melted electrolytic iron to which 70 pm N was vacuum-meltedadded. The secondary texture is "near {554}<225>" for material cold-rolled 75 to 90 pct, the sharpness of the texture increasing with increased rolling reduction and with decreased annealing temperature. At reductions of 95 and 97.5 pct the secondary texture is &apos;"near {322)(296)". Both secondary orientations also exist as major components of the primary re-crystallization texture. Development of a strong "near {554) (225)" secondary texture appears to depend on the evolution of the Primary texture to a transition texture depleted in orientations near the secondary orientation before the onset of secondary growth. A variety of qualitative experinzents have been used to show that nitrogen is important in limiling primary grain growth. The presence of nitrogen does not seem essential for the establishment of a transition texture, but a loss of nitrogen during annealing may facilitate growth of grains in the secondary orientation. Secondary grains we shown to form initially at the specimen surface. This is not thought to indicate that surface energies are important in the growth process. It is proposed that the quasi-two-dimensional character of surface grains permits discontinuous growth parallel to the surface before secondary growth of interior grains is possible. An earlier study of recrystallization textures in 90 pct cold-rolled electrolytic iron showed that secondary recrystallization occurred after annealing for several days at 700C1 This type of secondary recrystallization, which had not been reported previously, results in the formation of a strong texture, best described by the indices "near {554}(225)". The purpose of the present work was to investigate the effect of various processing variables on secondary recrystallization in this material and determine the mechanism of secondary grain growth. LITERATURE REVIEW An understanding of the mechanism of a secondary recrystallization process depends on knowing: 1) how grains in the secondary orientation come to be in the primary recrystallization texture; 2) why normal grain growth does not occur; and 3) what factors determine the strength of the secondary texture. For secondary growth of grains of a particular orientation, a certain minimum fraction of the grains must be in that orientation after primary recrystallization. This requirement is apparently satisfied "naturally" in certain systems, i.e., when the primary texture obtained by rolling and recrystallizing material initially randomly oriented contains a sufficient fraction of primaries in the secondary orientation. However, in other cases, e.g., {110}<001> and {100}<001> secondary growth in silicon iron,2 it is necessary to enhance the fraction of primary grains in the secondary orientation by rolling and recrystallizing textured material. In the present case, the "near {554}<225>" orientation is contained within the spread of orientations found in the primary recrystallization texture of iron or bbc iron-base alloys. In systems where the main driving force for secondary growth is the reduction in total grain boundary energy, secondary growth is observed only when normal grain growth is minimized. Four ways in which normal grain growth can be limited are: 1) Limitation by a strong primary texture. When a very strong primary texture consisting of a single component or twin-related components develop, most primary grains are separated from one another by relatively immobile small-angle grain boundaries. The classic instance of this is secondary growth into the primary cube texture in some fcc metals. 2) Limitation by precipitates. Precipitates present in the proper volume fraction with a suitable dispersion will limit primary grain growth. The role of MnS inclusions in impeding normal grain growth in Si-Fe is well-documented.5 3) Limitation by sheet thickness. Normal grain growth slows drastically when the mean grain diameter is of the same order as the sheet thickness. This effect has been used to obtain secondary recrystallization in thin sheets of high-purity silicon iron.&apos; 4) Limitation by solute impurities. It is well-established that certain impurity elements in solution can have a large effect on grain boundary mobility.&apos; However, there does not seem to be any secondary recrystallization process in which primary grain size stabilization has been shown to be due to the drag exerted on grain boundaries by dissolved impurities. In certain systems, e.g., secondary recrystallization in silver,&apos; the means by which normal grain growth is limited has not been identified, and solute-impurity limitation might be suspected. In order to understand the factors which determine secondary texture strength in three-dimensional growth, it is necessary to examine in more detail the current picture of general secondary recrystallization processes. Following Cahn,9 it is assumed that the primary grains have a range of sizes and that secondary growth of one of the large grains in this distribution is possible when it exceeds a critical size with respect to its neighboring grains. The critical size depends on the ratio ?S/?p, where ?s is some sort of average grain boundary energy between the potential secondary and the primary grains and ?p is some sort of average grain boundary energy between primary grains. For a constant primary grain size, the critical size for secondary growth increases as ?$/?p increases. May and Turnbull5 have incorporated the

Jan 1, 1969

By Steferson Ferreira de Oliveira

Desenvolvido nos últimos anos, o processo NDE, vem se tornando uma maneira promissora de usinar e nitretar simultânea a superfície de materiais metálicos. A Usinagem por Descargas Elétricas (EDM) é um processo de usinagem não convencional que tem grande potencial em aplicações de engenharia de superfície, ao melhorar a resistência superficial do material por meio de tratamentos termoquímicos, como por exemplo, a nitretação. Propriedades como: baixa densidade, boa resistência à tração (comparável à de muitos aços ligados) e excelente resistência à corrosão, possibilitam a aplicação do titânio e suas ligas nas indústrias aeroespacial, naval, química e automotiva e ainda no campo da medicina. Porém, raramente são usados como peças sujeitas ao deslizamento, devido a sua devido à sua baixa resistência aos mecanismos de desgaste abrasivo e adesivo e alto coeficiente de atrito. O tratamento termoquímico de nitretação pode solucionar esta restrição. Além de aumentar a resistência ao desgaste, o nitreto de titânio melhora a biocompatibilidade de suas ligas. O objetivo deste trabalho foi estudar a camada nitretada na liga de titânio Ti6Al4V por meio do processo de Nitretação por Descargas Elétricas (NDE), usando como fluído dielétrico solução de água deionizada e ureia granulada, como fonte de nitrogênio. Uma máquina de EDM por penetração foi utilizada no processo. Cobre e grafite foram utilizados como materiais dos eletrodos ferramenta. Foi avaliada a usinabilidade da liga Ti6Al4V com solução de água e ureia, relacionada aos parâmetros: taxa de remoção de material (TRM), taxa de desgaste (TD) e desgaste volumétrico relativo (DVR) para eletrodo de cobre e de grafite. Para caracterizar a camada nitretada foram realizadas microscopia óptica e medição de microdureza Vickers. A formação de nitretos na superfície foi avaliada por meio de difração de raio-x. Imagens metalográficas da seção transversal da superfície mostraram a formação da camada nitretada, devido ao ganho no valor da dureza. Os parâmetros relacionados à usinagem apresentaram valores que indicam um melhor desempenho quando se usa eletrodo ferramenta de cobre em relação à grafita. Nitretos de titânio foram observados no difratogramas da amostras nitretadas por NDE.

Oct 30, 2017

The Bureau of Mines in the Department of the Interior is increasingly concerned with the safety and health of personnel engaged in coal-mining operations, particularly below ground. The Bureau is also concerned with improving the utilization of domestic mineral resources, and reducing the environmental impact of mineral operations. One obvious way to improve safety and minimize health hazards would be to eliminate coal mining entirely by bringing the energy value of the coal to the surface in some other way, such as by partially burning it underground to form combustible gases and bringing these gases to the surface, where their energy content can be put to use. This technique might also improve the utilization of the coal resource. ? Accordingly, the Bureau of Mines, interested in re-evaluating underground coal gasification technology in terms of current and expected conditions in the United States, requested Arthur D. Little, Inc., (ADL) to appraise the technology to determine: ? Whether the current (1971) state of the technology offers a technically feasible method for gasifying coal underground that is applicable to the reserves of bituminous and lower rank coals in the United States. ? Whether a program of research and further development of the technology could ultimately make it a technically feasible alternative to current open-pit and underground coal mining operations. ? What the nature and cost of further research and development work in the technology should be.

Jan 1, 1971

1. In 2002, a total of 763 nonmetal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Examples of nonmetal mining operations include the mining of clay, trona, barite, phosphate rock, gypsum, talc, gemstones, and pumice. Nonmetal mines comprised 5.3% of all mining operations. • Nonmetal mining operations are located in all but nine states or territories (Alaska, Delaware, Maine, New Hampshire, Rhode Island, Vermont, Wisconsin, Puerto Rico, and the Virgin Islands). • Mines producing common clay comprised 29.2% (n = 223) of all nonmetal mining operations.

Jan 1, 2004

By Zviad Kovziridze

Structure of celsian ceramics in BaO-Al2O3-SiO2system is studied with electron microscope in the entire temperature region of baking interval. The process of the pores filling and the full consolidation of material growth at comparatively high temperatures of baking intervals are described.

Jan 1, 2006

By Lauri Gregg

How Can Man Meet the Carbon-Free Energy Challenge ? ? Increases in Energy Efficiency can displace 1/2 to 2/3 of the Carbon-Free Energy required to stabilize at 550 ppmv ? Renewable Energies require too much land and thus can displace 5 to 10 % of the energy requirement ? Large new sources of carbon free energy are needed ? Conservation is desirable but provides only a small and variable contribution ? People will have to adjust to higher levels of CO2 in the atmosphere as energy demand continues to grow

Nov 1, 2002

By Y. Wang

Phosphates and fluorides are used as regulators for the removal of silicates from diasporic-bauxite both in direct and reverse flotation. While using dodecylamine chloride as a collector, micro-flotation studies showed that sodium hexametaphosphate has stronger depressing power on diaspore than on silicate minerals with increasing sodium hexametaphosphate concentration at pH 6.5, but sodium fluorosilicate shows poor depression on diaspore with increasing sodium fluorosilicate concentration at the same pH. Zeta potentials of diaspore and silicate minerals become more negative both in the presence of sodium hexametaphosphate and sodium fluorosilicate. Adsorption density studies indicated that the adsorption density of sodium hexametaphosphate on diaspore is much higher than that on silicate minerals at the concentration of 75 mg/L. FTIR spectroscopy studies show that sodium hexametaphosphate interacted with the Al atoms exposed on the diaspore and silicate minerals surfaces to form P?O?Al bonds through the P02 groups. It is possible that sodium fluorosilicate interacted through F- or [SiF6]2- with silicate minerals surfaces based on the analysis by AES.

Jan 1, 2006

By G. L. Tufford, R. L. Bleifuss

Low-grade manganiferous iron ores of Minnesota&apos;s Cuyuna Range, in general, do not respond to conventional mineral dressing techniques because of their fine-grained texture. Reducing these ores to magnetite with subsequent magnetic separation and flotation have not given satisfactory results because, in many instances, concentrate grade and manganese recovery are low. Metallization of iron and concurrent reduction of higher manganese oxides to MnO, as in the R-N process, followed by recovery of iron by magnetic separation and manganese by leaching, seems to be a technically feasible process. High-temperature x-ray diffraction studies show that solid-state reactions between iron and manganese, with the formation of intermediate iron-manganese oxides, occur during reduction and affect recovery of both iron and manganese from the final product. Solid state reactions also occur between FeO, MnO, and SiO, at temperatures as low as 900°C. The kinetics of these reactions are such that they become an important factor in the treatment of ores by the R-N process. These investigations suggest a temperature and gas composition cycle that would maximize both iron and manganese recovery. During the past ten years, iron ore shipments from the Cuyuna Range of Minnesota have decreased sharp1y. Because of adverse grade, structure, and cost, many Cuyuna ores are no longer competitive with high-grade foreign ores and domestic pellets. The low-grade manganiferous iron ores from the Cuyuna Range, in general, do not respond to conventional mineral dressing techniques because of their fine-grained texture. Reducing these ores to magnetite for subsequent magnetic separation and flotation has not given satisfactory results because concentrate grade and manganese recovery are often low. However, a technically feasible process appears to be metallization of the iron and concurrent reduction of manganese oxides to MnO with recovery of metallic iron by magnetic separation and extraction of manganese from the tailings by leaching. In 1962 the R-N Corp., with a grant from the Area Redevelopment Administration, conducted an amenability study of the metallization of manganiferous iron ore from the Cuyuna Range. The results of this preliminary investigation were sufficient to interest the Economic Development Administration in sponsoring further studies of the process with emphasis on secondary recovery of manganese from the nonmagnetic tailings. Inasmuch as the metallization process has considerable influence on the final form of the manganese - its texture and distribution between the magnetic concentrate and nonmagnetic tailings-the investigation included a study of metallization of the ore as well. Therefore, the investigation conducted at the Mines Experiment Station covered three interrelated phases: (1) laboratory R-N roasting studies and magnetic separation tests, (2) laboratory chemical extraction experiments of the nonmagnetic tailings, and (3) a mineralogical study of the crude ores and their various roast products. High-temperature x-ray diffraction investigation of the Fe-Mn-Si0,-0, system is the main topic of this paper and an extension of the mineralogical work. GENERAL GEOLOGY The Cuyuna Range is known for its complicated geologic structure, complex orebodies, and generally indifferent response to attempts at conventional beneficiation. Several geologists have made intensive studies of the Cuyuna Range, including Leithl (1907), ~darns&apos; (1910), Zapffe3 (1925), Grout and Wolff4 (1955), and schmidt5 (1963), whose study was the most comprehensive of all. The Range is covered with glacial deposits - till, out-wash, and lake sediments -up to 250 ft thick. Bedrock stratigraphic units of the Cuyuna Range consist of three tightly folded Precambrian sedimentary formations. The lower unit is the Mahnomen formation, composed of 2000 or more feet of argillite, slate, siltstone, and quartzite. The middle unit is the Trommald formation, which varies from 45 to 500 ft in thickness and comprises the major iron-bearing formation. The upper unit is the Rabbit Lake formation, consisting of over 2000 it of argillite, slate, and interbedded lenses of lean iron formation. In the central part of the Cuyuna Range, the units have been folded into a series of

Jan 1, 1969

By T. Sterry Hunt

SINCE: the date of my previous paper on this subject, presented at the Cincinnati Meeting, February, 1881, and published in our Transactions, vol. xii., p. 459, I have had occasion to revisit the Canadian apatite region, and to collect further data concerning its geognosy, which I hope to describe at a future time. At present, I shall put on record a few brief observations concerning the more recent operations in apatite-mining in the Lievre district, to the north of the Ottawa River, where the mines are as yet confined to a small area in the townships of Buckingham, Portland, Templeton, and Darry; the earlier workings having been along the Rideau Canal, to the south of the Ottawa. The large mining operations lately undertaken in the Lièvre district show that the crystalline phosphate of lime or apatite belongs to lodes of great size, which traverse the ancient gneiss of the region. These lodes include a granitoid feldspathic rock, and a pyroxene rock, with large masses of quartz, of carbonate of lime, of pyrites, and of apatite. All of these often show a banded structure, riot unlike that of the gneiss, to which they- are evidently posterior, arid of which they

Jan 1, 1886

By L. W. Saperstein

P.J. Ehret By and large, I agree with many of the precepts discussed in the Saperstein paper. I believe there is much more that can be done on the local level to involve both government and planning in the mine permit review process. Admittedly, much can be done to improve discussion between the state regulatory authority, local authorities, and mine operators. However, I strongly disagree, as suggested in the paper&apos;s conclusion, that such a system, as outlined in Saperstein&apos;s paper, could result in a reduction of review time or a lowering in the cost of permitting. The implementation of such a system by its very nature would only add a new level of bureaucracy to an already cumbersome process. This system, in my opinion, would only add to the cost of permitting and the time necessary to obtain a permit. Admittedly, it would achieve the result of adding local influence into the permitting process, but at what off-setting cost? It has been my professional first-hand experience and observation in the permitting and lands unsuitable processes to note that under the present system, local governments that do feel they have a stake in local mines and actively ad¬vocate their position (not simply comment), have had significant input into the conduct of mining and reclamation plans in their areas. Mining companies that mine in these areas are aware of local interests and attitudes, and do consider them in their plans. Simply put, local governments that want to get involved and want to play significant roles can and do. Those that do not advocate a position or have no input to offer do not. Although the present system is not as direct in effect in regard to local control as Saperstein&apos;s, it does work. It does so without the red tape that would result from developing miniature regulatory authorities in every county in which mining occurs. Although local input is important, there are many more sections of the Surface Mining Control and Reclamation Act (SMCRA) than Sections 508(a)(8) and 522(a)(3)(A) that also are important. It appears Saperstein&apos;s paper may overindulge these sections. An additional specific comment is made in regard to the statement that while local areas benefit from mining (wages, salaries, and purchases), they also endure environmental deterioration caused by mining affects. It is believed that the whole purpose for which SMCRA and its resulting regulations were enacted and developed was so mining would not be permitted if significant environmental deterioration could occur. Therefore, it could be argued that this point under current law is moot. Reply by L.W. Saperstein P.J. Ehret writes in a reasoned and rational way and makes some good points. The arguments in favor of central control of the designation process reflect all of the benefits associated with central environmental control: consistency of enforcement, efficiency of operation, ease of communication among enforcing agency, etc. Nonetheless, the decision to mine or not to mine is a landuse decision which, in substance, is similar to the decision to build a shopping mall, a new highway, or a housing subdivision. Although, state and federal governments&apos; interests in the protection of public welfare are real and are expressed properly in mining laws and mining enforcement agencies (OSM, Illinois Department of Mines and Minerals, etc). I continue to maintain that the permitting and designation processes should originate with local government, which is in keeping with the American tradition of delegation of the land-use decision to local or regional government.

Jan 4, 1984

By Pierre Louis, Jacques Duparque

ACTIRED is a new process for gold and silver elution from activated carbon based on the addition of hydrazine, needing no extra investment and which generates a systematic increase in elutions kinetics. This process either operates at a lower temperature and maximizes financial gain or reduces elution time or operates at a compromise between these two options taking into account the needs of each plant. Industrial use of the process at SNC Lastours, France (Zadra elution column 3,5 bars -125°C) has proved at 95 ° C the following points:

Jan 1, 1995

By Jeffrey A. Straw, Joseph P. Jr Shinko

Ground vibration produced by blasting operations within South Florida, due to saturated soil conditions, generates surface vibration waves that may be measurable over distances of 3 - 5 miles from the source, and perceptible at distances of up to 2 miles. Structures above ground usually receive the most of the attention from the effects of high vibration levels. During construction of the Trilogy Development of the Swerdlow Companies, blasting was completed in a lake excavation immediately adjacent to the City of Pembroke Pines Utility Department, Deep Injection Wells No. 1 and No. 2.

Jan 1, 1994

By G. T. Lineberry, W. J. Wiehagen

This paper discusses a practical method for enhancing the performance of mining work crews. The method, described as the Work Crew Performance Model (WCPM), seeks to define performance variability within similar tasks of an underground work crew. Key components of the WCPM include: (I) job definition through task analyses; (2) the ranking of job elements by perceived cost consequence; (3) observational techniques to establish performance baselines; and (4) cost linkages between adherence to task procedures and measures of consequence for noncompliance. The components of this model emphasize a reliance on learning from a veteran work force and using that information to reinvest in strategies to enhance safety and efficiency. These strategies are not limited to technologic efforts but include consideration of the so-called "soft-skill technologies" aimed at reducing variability in individual performance and at effecting a continuous improvement in overall system effectiveness.

MONDAY, FEB. 17 9.00 A.M. to 9.00 P.M. Registration at Institute Headquarters. 9.00 A.M. Meeting of Committee on Development of the Activities of the Institute, Room 905, 9th Floor. 10.00 A.M. Simultaneous Sessions of Institute of Metals Division, Room 2, 5th floor. Industrial Organization, Room 1, 5th Floor. 12.30 P.M. Luncheon at Headquarters, 5th Floor. 2.00 P.M. to 4.25 P.M. Simultaneous Sessions of Institute of Metals Division, Room 2, 5th Floor. Industrial Organization, Room 1, 5th Floor. Petroleum and Gas, Room 905, .9th Floor. 2.30 P.M. Sightseeing trip by automobile for the ladies. Among the points visited will be: The American Museum of Natural History. The Episcopal Cathedral of St. John the Devine. The Spanish Museum. The American Geographical Society. The American Numismatic Society. The visits will be followed by Tea. 4.30 P.M. Memorial Service to Dr. Rossiter W. Raymond, Auditorium. 8.30 P.M. Smoker, 5th.floor.

Jan 2, 1919