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By J. J. Mulligan, F. F. Colcord, E. F. Kern

The electrolytic separation of silver and gold has been practiced by the refineries in the United States for a good many years, and probably because of frequent visiting between officials of plants and the consequent exchange of views, operations in the various silver and gold refineries are very similar. We find, for instance, they practically all use electrolytes of approximately the same composition, which, no doubt, is more the result of experience than of studies of electrolytes. At the new electrolytic parting plant of the U. S. S. Lead Refinery, Inc., East Chicago, Ind., considerable attention has been given to the composition of electrolytes, especially to their conductivity and their effect on the character of the silver deposit. We are not aware that anything has been recently published on this subject and are, therefore, presenting such data as we have with the idea that, although it will not be wholly new, it may stimulate interest in the subject. Effect of Copper Content on Conductivity The first work was to determine the specific conductivity of silver nitrate and copper nitrate solutions. Concentrated solutions of silver nitrate and copper nitrate were prepared by dissolving analyzed chemically-pure salts in distilled water, and determining the silver and copper in each. Definite amounts of the concentrated solutions were taken, mixed and diluted to a definite volume. The silver and the copper were determined in each of these solutions and the conductivity was then determined. The plotted results are shown in Figs. 1 and 2. The effect of increasing quantities of silver and copper is readily seen. A comparison of the two sets of curves shows conclusively the benefit of holding the copper content of the electrolyte above 5C g. per liter, as its effect is to increase greatly the conductivity in an approximate propor-

Jan 1, 1926

By S. A. Montague

In spite of the many new insulating materials, both synthetic and manufactured, that have been put on the market since the end of World War II, and notwithstanding the many millions of dollars applied to the development of synthetic mica, natural block mica1 is still a most indispensable insulator in various electronic components. It will remain so, barring some spectacular break-through in research that might provide a substitute fully acceptable as a replacement for mica in all of its superior properties. But this is not to say the future for mica is assured, or free from serious problems. Technological advances have created problems requiring a solution to be found if future requirements are to be filled.

Jan 1, 1962

By Antti Roine

Sulfidic zinc concentrates are usually roasted in a fluidized bed furnace into sulfur-free oxide form. Metallic zinc is produced from this oxidic calcine using hydrometallurgical leaching, solution purification and electrowinning stages. The roasting step is necessary because zinc oxides are easier to dissolve using traditional leaching methods than zinc sulfides. The Kokkola Zinc smelter uses various types of zinc concentrates and secondary materials as feed mixture. This makes it difficult to find optimum process parameters for the roaster when the composition and particle size distribution of the feed mixture varies even on a daily basis. Certain conditions may even cause difficult accretion problems or increase the amount of calcine in the process off-gas line excessively. A thermochemical heat and material balance model was developed for process advisor, in order to estimate the effects of different process parameters (temperature, process air coefficient, concentrate feed, oxygen enrichment, water feed, etc.) on the heat balance, roasting temperature and calcine composition. This model was constructed using the heat balance module of HSC Chemistry 4.0 software. The prevailing chemical compounds in the concentrate and calcine were verified using mineralogical analyses and equilibrium calculations. The roasting process seems to operate near chemical equilibrium conditions, if the behavior of the main components is considered. This paper describes briefly the basic principles of the calculation model and outlines the results with several diagrams and discussion. The calculated results were in reasonable agreement with the recent process air oxygen enrichment and water feed test campaigns carried out at Kokkola in 1999.

Jan 1, 2000

By V. P. Mehrotra

The effect of dissolved ions present in plant water on the flotation of phosphate ore from central Florida was investigated. Of the three most abundant ions, namely Ca++, Mg++ and SO4--, calcium ions were the most detrimental in the flotation of phosphate with sodium oleate collector. In one feed, a 10 ppm concentration of Ca++ ions reduced the BPL recovery from 86% to 46% whereas in the other a 40 ppm concentration lowered the recovery from 90% to 52%. The effect of Na2C03, NaHC03, Zeolite and EDTA to remove ca++ ions from water and hence improve apatite flotation was also studied.

Jan 1, 1986

By Luben Savov

This paper presents recent research works on the removal of the tramp elements Cu, Sn, Zn and Pb from steel. The evaporation of Cu and Sn in iron-based melts treated at reduced pressure of the gas phase was studied in a vacuum induction melting furnace. The effect of chamber pressure, temperature and melt composition was investigated. Since the main source of contamination of steel with Sn and Zn is the recycling of tinplate and zinc coated steel, respectively, possibilities for the removal of meta1ic coatings in a scrap pre-treatment stage were studied, too. Tin was removed in the temperature range 400-5S0°C by treatment with reactive gases featuring high sulphur potential. Zinc can be removed by evaporation or by a combination of thermal and mechanical treatment. The paper discusses the thermodynamics of Pb in carbon-saturated iron melts, too.

Jan 1, 2001

By Bruce C. Fielder

"The concentration of uranium in orebodies discovered in the Athabasca Basin of northern Saskatchewan over the last 20 years has increased by a factor of 100. These high grade uranium orebodies are associated with high concentrations of radionuclides, complex mineralogy and an elemental makeup that includes base metals, arsenic, and molybdenum. Exploiting these high grade ores has required metallurgical advances in milling, tailings disposal and effluent treatment as well as changes in the design of uranium mills.This paper describes the most significant advances, including advances in dealing with the environmental issues which have become more prevalent in recent years. The milling processes of the Cluff Lake Mill, Key Lake Mill, Rabbit Lake Mill, and McClean Lake Mill are compared to illustrate both similarities and differences necessary for milling different orebodies.BackgroundUranium mining in Saskatchewan started in 1953 when the Beaverlodge Mine, owned by Eldorado Nuclear Limited (Eldorado), came into operation at Uranium City. Development in the Athabasca basin started in 1975 when the Rabbit Lake mine came into operation. This was followed by the start-up of the Cluff Lake mine in 1980 and the Key Lake mine in 1983. The McClean Lake mine is forecast to start up in the near future. The McArthur River mine recently received construction approval and the Cigar Lake Project and the Midwest Project are currently in the environmental approval process.The Beaverlodge operation ceased production in June 1982 after nearly 30 years of operation. The Rabbit Lake mill processed Rabbit Lake ore from 1975 until 1985, Collins Bay R-Zone ore from 1985 until 1993, and is currently processing ore from the Eagle Point mine (Bharadwaj, Jarvi and Lam, 1996). The Cluff Lake mill processed ore from the D- Orebody from 1980 until 1984. Since then the Claude orebody has been processed and the OP and DS orebodies are presently being milled (SRK. Senes and Melis, 1987; and Cogema Resources Inc. 1994 ). The Key Lake mill processed ore from the Gaertner ore body from 1983 until 1989 and Deilmann ore has been processed since (Cameco Corporation, 1992b and I 994a). Processing of McArthur River ore in the Key Lake mill is scheduled for 1999. The McClean Lake mill will be processing ore from the JLR, Sue and McClcan orebodies associated with the McClean Lake mine. In future ore from the Cigar Lake and Midwest projects will be processed in the McClean Lake mill. (Minatco Limited. 1991a)."

Jan 1, 1998

By J. E. Tiffany

Some of the gases produced by permissible explosives on detonation are poisonous, and the probable hazard involved by the inhalation of carbon monoxide in the past has been evaluated from results of tests in the Bichel Gage. Tests have now been made in the Experimental Coal Mine of the Bureau of Mines at Bruceton, Pa., to determine the composition of the gases obtained under actual mining conditions for the purpose of comparing these, results with those found by the Bichel gage tests. Two permissible explosives were procured for these tests, one that produces a relatively low quantity of poisonous gases in the Bichel gage (24.8 liters per 1-1/2 pounds of explosive) and another that produces a relatively high quantity of poisonous gases (94.6 liters per 1-1/2 pounds). The first of these is designated by the Bureau of Mines as a class A4/ explosive and the other is designated a class B explosive. In comparison with Bichel-gage tests, the shooting of permissible explosives in a coal shot hole resulted in a large reduction in the quantity of carbon monoxide, the principal poisonous gas, which; in the mine tests, was only 22 percent of that found in Bichel-gage tests: The quantity of carbon monoxide from the class B explosive in Bichel-gage tests was 3.8 times larger than that from the class A explosive; in the coalmine tests the ratio was 4:1. The concentrations of carbon monoxide in the mine tests, as determined by analysis of the atmosphere in an enclosed space resulting from shooting 1-1/2-pound and 3-pound charges of the class A explosive, were 0.03 and 0.06 percent, respectively, and the concentrations from 1-1/2-pound and 3-pound charges of the class B explosive were 0.10 and 0.24 percent.

Jan 1, 1950

By M. Hozayen, E. S. Radwan, P. A. Nawrocki, A. Jebbouri

"A major geomechanical study was conducted for one of the UAE onshore oil fields with the purpose of studying reservoir rock properties and stress distribution, based on which a 3D coupled reservoir geomechanical model was built. This model was later used for wellbore stability analysis and for analyzing the effect of fractures on future reservoir production performance, including fracture deformation and permeability evolution occurring due to reservoir depletion and resulting changes in local stress field. The subject of this study was a complex fractured Upper Cretaceous carbonate reservoir characterized by high degree of heterogeneity, both vertically and laterally. Wellbore instability related drilling problems were encountered while drilling the wells in this field. The problems were mainly in drilling the horizontal wells, including breakouts and mud losses. Experimental results of laboratory tests are summarized in this paper whereas wellbore stability analysis and formulation of a 3D geomechanical model that was built for that purpose is summarized in a sister paper (Part II).A suite of tests reported includes tensile strength, uniaxial and triaxial compression and permeability under stress at simulated reservoir conditions. All tested rocks have been grouped into twelve test units and reservoir geology, rock types and challenges related to designing a viable sampling and testing program for a big reservoir are discussed first followed by sample selection criteria and details of the testing program. All test units showed brittle behavior at zero confinement and some samples showed similar behavior at low confining stresses. With confining stress increase, the behavior gradually turned to plastic but some samples showed features of ductile behavior even at low confinement.Obtained experimental data have been summarized in the form of strength criteria and correlations. The Mohr-Coulomb strength equations were obtained for each test unit and also for the averaged values. It was noticed that triaxial compressive strength (TCS) increases with decreasing porosity or increasing density but their influence on TCS is getting smaller with confining pressure increase. Good correlation of porosity and density with Young’s modulus, Poisson’s ratio, unconfined compressive strength (UCS), friction angle, cohesion and tensile strength has been noticed and there was an increasing trend between the confining pressure and TCS. Rock type (mud or grain supported) was not influencing the TCS as much as porosity and density and the two lithologies encountered affected TCS approximately in the same way. These results and correlations are summarized and explained in this paper. They were further used in the numerical modelling part (Part II) of this paper, Hozayen et al. (2015). It is also concluded that rock lithology is not a decisive factor and mechanical properties of tested rocks should be rather considered dependent on porosity and permeability. This helped greatly in reducing the number of tests that had to be performed."

Jan 1, 2015

By S. K. Kawatra

A growing concern for pyrometallurgical operations is the generation of airborne particulates. These particulates can be generated by combustion processes, or by materials handling. Regulation of these particles by the EPA has become progressively more stringent, first for particulates finer than 10 micrometers (PM10), which are particles fine enough to be inhaled into the lungs. Then, restrictions were introduced on emissions of particles finer than 2.5 micrometers (PM2.5), which are fine enough to become embedded in lung tissues. The next stage of regulations is likely to be ?nanoparticulates,? particles finer than 100 nanometers, which are in a size range where their very high surface area leads to enhanced reactivity. While all of the health effects due to nanoparticulates have not yet been determined, there have been enough studies to indicate that there is a problem, and restrictions on nanoparticulate emissions are only a matter of time. In this paper, it will be demonstrated that dry handling, comminution, and combustion sources represent a significant concern for both PM and nanoparticulate emissions. In regards to dry handling, the effects of utilizing effective dust suppressants on PM and nanoparticulate emissions will be explored.

Jan 1, 2006

By J. Drew Potts

The U.S. Bureau of Mines identified respirable dust sources and controls on four continuous auger mining sections, two with relatively low dust levels and two with high levels. Factors adversely affecting dust levels included auger equipment design, continuous haulage, and low seam height. Dust controls included ventilation practices and spray systems. Maximizing airflow seemed to reduce dust levels most. Air leakage and shock loss can be reduced by constructing stoppings with brushed-on mortar containing fiberglass and by keeping areas between curtains and ribs free from obstructions and storing equipment not essential for face activities in outby crosscuts. Curtain configuration, setback distance, and installation can also affect dust levels. Use of both blowing and exhausting curtains is the most effective configuration. Setbacks from the face should not exceed 15 ft. Installing brattice curtains at least 5.5 ft from ribs, when entries are 26 ft wide, minimizes velocity head. Installing curtains tightly against the mine roof and floor helps maintain a forward airflow movement in the center of the mine heading; curtain overlap can create a tighter seal. The wet-auger spray system also effectively controls dust, provided the mine is already exercising good ventilation practices.

Jan 1, 1989

By John V. Beall

Copper production in the. United States in 1972 amounted to 1,658,000 tons according to the USBM. This figure is up over 1971 but falls below 1970 production of 1,719,101 tons. This report is essentially about the status of copper mining operations in the U.S. and is an update and expansion of the report "Southwest Copper-A Position Survey" published in [A=], October 1965. At that time, the trend was toward using larger equipment to mine lower grade ore and toward the expansion of dump leaching practice. That trend continues today but, it is overlain by intensive activity to comply with existing environ¬mental legislation and uncertainty over proposed revisions of venerable laws governing mining. In the U.S. today there is, practically speaking, no excess smelting capacity so that expansion of copper production through the startup of new mines is inhibited. Owners of a large undeveloped orebody would have to decide before going into production whether to sell the concentrates offshore, which has many problems, whether to try one of several unproved chemical processes for producing refined metal from concentrates or embarking on the construction of a traditional pyrometallurgical plant in the face of considerable uncertainty over the pollution standards that eventually must be met. The situation is such that not only is the present rate of U.S. copper production threatened but the ability to meet projected increased demand in the years ahead may have been severely retarded.

Jan 4, 1973

By S. V. Subramanian

The tool material and the machine design for high speed machining are well advanced over the last decade but the steel design has lagged behind. The paper examines the design of steel in order to control the sliding tribology for high speed machining under dry machining conditions. In high speed machining of steel, accelerated chemical wear of the tool occurs once atomic contact is established at the tool-chip interface, resulting in poor tool life even with high performance tools such as cubic boron nitride. Recent research has confirmed the occurrence of nanocrystalline grains in the interfacial layer of the chip at the tool-chip contact. The volume percentage of grain boundary is increased significantly (10 to 30%) as the nanocrystalline grain size is decreased well below 30 nm. The solubility of tool material into the nanocrystalline grain boundary is two or three orders of magnitude greater than in the crystal lattice. Further the kinetics of diffusion in the grain boundary is seven or eight orders of magnitude greater than in the crystal lattice. Enhanced nanocrystalline grain boundary diffusion occurring in the interfacial layer at the tool-chip contact causes the accelerated chemical wear. Significant improvement in tool life could be achieved by engineering glassy oxide inclusions in steel, designed to self-lubricate the tool-chip interface in-situ at higher cutting speeds. Thus the control of sliding tribological condition at the tool-chip interface is key to suppress nanocrystalline layer formation at the tool-chip contact and hence prevent accelerated chemical tool wear. Sulfide inclusions are designed essentially to promote chip fracture. In addition, sulfide inclusions are designed to act as a diffusion barrier at the tool-chip interface. The application of inclusion engineering concepts to enhance the tool life in high speed machining will be demonstrated with a suitable case history.

Jan 1, 2006

This paper presents a summary of the technical achievements of the Port Pirie Smelter in 100 years of lead smelting and refining. It also aims to give where possible the reasons or circumstances that led to the achievements. The major achievements took place in the areas of sintering, blast furnace, copper drossing, copper recovery, lead refining and slag fuming.

Jan 1, 1989

By Joshua Hoffman, Rob Farnfield, Catherine Johnson, Braden Lusk, Morgan Lane

IMESAFR (IME Safety Analysis for Risk) is a quantitative risk assessment software tool developed by the Institute of Makers of Explosives (IME) and A-P-T Research, Inc. It is used for managing risk in the commercial explosives industry, the newest version of the software was completed in 2012. This paper discusses the use of this software package in conjunction with data collected for a television series on the reenactment of the ‘London Blitz’, a 57-day bombing of the City of London in 1940. In this reenactment, purpose built structures using period design and materials were constructed at a test facility in the North of England. Five devices ranging in size from 20 kg (44 lb) to 1100 kg (2400 lb) were detonated at varying distances from the structures; each blast was monitored by EPC-UK and the resulting structural damage was analyzed. Data recorded from the blasts included high-speed videos, photographs before and after each event and air overpressure readings. The same data was inputted into the IMESAFR software package to assess the risk imposed on the residents of London during this time. The appropriateness of this tool for evaluating structures built using historical practices is discussed. Data from the full scale tests is compared to effects predicted by IMESAFR. Further analysis of the risk recommendations produced by IMESAFR is compared to the actual damage assessed during the large scale tests.

Jan 1, 2014

By E. A. Reilly, G. R. Gardner, F. P. Lasseter

THE methods that may be applied to the treatment of slurries and water, as these are related to practical coal-preparation problems, are concerned essentially with the movements of solids suspended in water. It is assumed that there are no fundamental differences between the principles involved in the treatment of coal slurries and the phenomena encountered in general mineral-dressing practice, and the latter are presented in some detail. Basic principles are correlated with present practice for both the anthracite and the bituminous coal. fields, and meth¬ods are discussed which are designed to utilize best all the material subjected to treatment and suggest a sound approach to the solution of problems relating to the return of clear water to process or to streams. In order to approach the practical phases of the subject with sufficient understanding of the basic principles, it is necessary to discuss two types of phenomena that are applicable. The first is flocculation and the second is sedimentation. Descriptive matter is given covering the various meth¬ods and types of equipment employed to conduct these operations, with emphasis on their application to water and coal-slurry treatment.

Jan 1, 1943

By David Browne

THE literature dealing with the physical constants of nickel is so fragmentary and unrelated, that a synopsis presents unusual difficulties. It is only within the last few years that investigators have understood the importance of placing on record not only the determinations they have made but also the composition, physical treatment, and past history of the material investigated. For this reason much of the earlier literature is valueless. Determinations have been made of the same physical constants on samples differing widely in origin, composition, and treatment, and the results differ widely among themselves. In the first place nickel is almost as flexible a term as steel. Its physical properties are widely influenced by its composition and treatment. It absorbs large quantities of gases and is exceedingly difficult to prepare in a state of chemical purity comparable to gold, silver, or copper. It is vitally affected by thermal and mechanical treatment. Hence in the following pages the recorded literature, where quoted, must be accepted with a certain reserve and used, as far as possible, as a check on later observations, in which these important factors are noted. In every case where new determinations are given, an attempt has been made to record all available information concerning the composition and treatment of the material used so that the data may serve as steppingstones toward a wider knowledge of the properties of the metal. As this synopsis is an attempt by men of metallurgical training to do what should long before have been clone by physicists, it is to be expected

Jan 9, 1919

NORTH AMERICA Number Members Alaska 31 Canada 302 Mexico 175 Newfoundland 3 United States Alabama 52 Arizona 131 Arkansas 9 California 723 Colorado 184 Connecticut 98 Delaware 19 District of Columbia 133 Florida 16 Georgia 6 Idaho 61 Illinois 241 Indiana 57 Iowa 7 Kansas 32 Kentucky 33

Jan 1, 1932

By T. E. Brower

SHORTLY after our previous paper on this subject was printed,1 we located a source of uncertainty in the results arising from the unexpected fact that hydrogen slowly reduces silica at 1100° C. in presence of iron, even when the iron nowhere touches the silica, although in absence of iron it does not do so. This difficulty has been completely obviated by the use of a small high-frequency furnace, which enables us to heat the specimen for analysis without raising the temperature of the silica vessel to a point at which any appreciable reduction of the silica glass occurs. We now describe this modification of procedure, and present some typical results obtained with it. For any given specimen of steel, the results are entirely definite and. reproducible, but their precise significance is still open to some question, as indeed is true of all methods of oxygen determination so far developed. Further elucidation of this question is to be expected from the cooperative comparison of the several methods now under way under the auspices of the Bureau of Standards at the instance of the Iron and Steel Division of the A.I.M.E.

Jan 1, 1934

By Lloyd Pollish, Robert N. Breckenridge

SUCCESS in any underground mining operation is determined by accessibility of the orebody, which in turn is dependent upon maintenance of passage- ways to the mining zones and temporary support of the voids caused by extraction of ore. This is accomplished by one or a combination of the following methods: timbering, back-filling, pillaring, or, more recently, rock bolting. Timbering has usually been the principal means of maintaining these underground openings necessary for mining operations. Timber, however, does not prevent ground movement beyond the scope of localized sloughing, which is indicated by the gradual failing of the timber itself. Besides this, timbering has always been a costly process, and with the decline of available supplies of timber close to the mining areas, mining men have constantly sought other methods of controlling ground.

Jan 7, 1954

By D. K. Crampton

The object of this work was to obtain and correlate information on effect of internal stress in variously drawn tubes on several properties. Also, a simple approximate method of comparing types of stress distribution in such variously drawn tubes was sought. There is also included some work on comparison of single and polycrystalline materials and effect of different types of operation and preferred orientation. Preparation of Material A series of tubes was drawn to study the effect of the type and degree of final reduction on various physical properties and the approximate distribution of stress intensity across the tube wall. The material used all came from a single heat of 70-30 brass melted in a regular production Ajax-Wyatt induction furnace. The analysis of the metal as cast was: copper, 70.36 per cent; lead, 0.04; iron, 0.02; zinc, balance. The material was cast in "shells" with 4 in. outside diameter and in. wall thickness. It was drawn part way down according to the usual standard mill schedule and then by suitable individual schedules to finish by a variety of types and degrees of drawing to the same final cases in every instance; namely, 0.750 in. outside diameter by 0.080 in. wall thickness. The exact final draws, together with the percentage area reductions, diameter reductions and gage reductions are given in Table 1. In fabricating these tubes, rather unusual precautions were observed to insure the elimination of ail variables not under immediate study. All intermediate anneals were carried out at about 1200" F. down to the so-called "cut-in size"; namely, 17/16 by 3/16 in. From this point on, all anneals were made at from 1050' to 1100" F. The greatest care was used all through to have the tubes as free from minor surface defects as possible. When such defects were visible on intermediate sizes they were carefully filed out. On the final draw to 3/4-in diameter the die was aligned with the greatest possible precision in order to insure as straight a tube as possible

Jan 1, 1933