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By Emil B. Milosavljevic

The photochemical reactions of cyanide ion induced by light were investigated in the presence or absence of a titanium(IV) oxide semiconductor photocatalyst. The light sources employed were the sun and arrays of either mercury or fluorescent (cool white) lamps. The results obtained verify that cyanide decomposes much faster when TiO2 is present in the solution and that it is first oxidized to cyanate. However, contrary to the previous studies, it is established that cyanide is subsequently further oxidized via nitrite all the way to nitrate irrespective of the light source. As expected, the rates of the oxidation processes decrease with the illumination source utilized in the following order: Hg-lamps > sunlight > fluorescent lamps. As nitrate is a significantly less hazardous contaminant than cyanide, complete photocatalytic oxidation of cyanide to nitrate may be a viable method for decontamination of cyanide wastes. Contrary to previous claims, we find that cyanide is slowly photochemically decomposed even in the absence of TiO2. For example, with the mercury lamps as the light source, in two hours, cyanide concentration decreases to essentially zero; up to 7% was converted to cyanate and the remainder to unidentified products.

Jan 1, 1992

By J. S. Dunning

The objective of this research by the U.S. Bureau of Mines was to determine the effects of AI additions on the sulfidation resistance of Fe-Cr-Ni alloys. A series of Fe-Cr-Ni alloys with and without -additions of 4 pet AI were tested in a wet S vapor atmosphere at 677 C. A study of the morphology and composition of corrosion scales indicated a different corrosion mechanism for AI-free alloys compared with AI-containing alloys. Aluminum-containing alloys formed a compact, tightly adherent layer at the metal-scale interface that reduced corrosion rates by a factor of 3 to 10 compared with that of AI-free alloys. The thin, adherent AI-containing scale limited inward diffusion of 0 and S to the base metal and outward diffusion of Ni from the base metal. Aluminum-containing alloys formed a three-layer scale in oxidizing-S environments, while AI-free alloys formed a less protective two-layer scale.

Jan 1, 1989

By Edward H. Peplow

Mr. Chairman; honored guests; ladies and gentlemen: The subject assigned me today by your committee, according to the program, is "the mineral industry and the public land law I have preferred to title the talk, "you can't mine here", for that is the essence of the message we, as an industry, have been getting from so many agencies of the federal government for so long. And, unfortunately, we can expect to hear the same message even louder and clearer -- with increasing frequency in future, unless. Every segment of the industry devotes the necessary time, energy and creative thought to combat successfully the forces that are writing and broadcasting that message. I said that agencies of the federal government are sending the message --- and this, of course, is true, the forest service, for example, and some bureaus of the department of the interior as well as others have appeared in recent years to be abiding by a policy designed to block mineral entry to as much of the public lands as possible and to wipe out existing mining claims.

Jan 1, 1967

By Donald A. Brobst

Barite, the sulfate of barium, occurs in many geological environments in sedimentary, igneous, and metamorphic rocks. The commercial deposits of barite may be classified into three major types. 1. Vein and cavity fillings that occur in rock fractures, along bedding planes, and in various solution structures. 2. Bedded deposits in which barite occurs as the principal mineral or cementing agent in stratiform bodies in sedimentary rocks. 3. Residual deposits occurring in unconsolidated material formed by the weathering of preexisting rocks. The geologic characteristics of each type of deposit are of fundamental importance to the successful search, development, and economic use of barite deposits.

Jan 1, 1980

By T. K. Mukcherjee

The importance of the processing of secondary resources such as solid industrial wastes and liquid effluents as well as byroducts for the recovery of the associated metal values hardly needs any elaboration. Such processing contributes in no small measure.towards the augmentation of the availability and the supply position of resources. As an added benefit, it leads to a reduction in environmental pollution caused by the undesirable waste materials. As some typical examples of secondary resources in the Indian scenario, mention' can be made of spent catalysts, metal/alloy scrap, ash, consumed batteries, flue dust, slag, sludge and slime, pickling solutions, spent acids; plating rinse solutions, spent etchants, waste water from synthetic fibre manufacture and from tanneries etc. These wastes constitute a source of a variety of non ferrous metals. In the processing of secondary resources like these, the techniques of hydrometallurgy such as solvent extraction play a pivotal role. This paper outlines the efforts made to use solvent extraction to recover(1) base metals. such as copper, zinc, nickel and cobalt from a number of secondary resources like cake, and sludge(2) refractory metals like molybdenum and vanadium from sulphidic byproducts and spent catalyst and (3:) nuclear metal like uranium from phosphoric acid. In the case of base metals, process flowsheet involving the use of acidic extractants such as DEHPA and PC88A have been optimised. The problem of iron removal from the leach liquor, "which influences the metal recovery process significantly, has drawn a special emphasis. hi the case of refractory metals, basic extractants .like Alamine 336 has been pressed into service to produce kilogramme. quantities of pure salts of molybdenum and vanadium, Finally, the paper gives a brief account of plant experience in recovering uranium from phosphoric acid, using 'a solvent system comosed of DEHPA and TOPO.

Jan 1, 1996

By Bruce W. Smith

Non-contacting, radioisotope density and level gauges are discussed. The characteristics of the more commonly used isotopes, the techniques of detection and the methods of presenting information are reviewed. The gauge parameters of accuracy, response time and long-term stability are tabulated with reference to calibration techniques and operating requirements. Automatic control systems, both pneumatic and electrical, are used in conjunction with density gauges on filter feeds, and in thickener underflow and heavy media processes. These systems are described. Procedures for installation, start-up and operator training are outlined, along with considerations of preventative maintenance and service requirements. Typical gauge system costs, including capital expenditure, installation, start-up and service, are presented, wherever possible, in order to provide a basis of comparison with more conventional systems.

Jan 1, 1964

By Viraj Parekh, Kinnor Chattopadhyay, Sina Mostaghel, Xiao Zhang

Electric arc furnace steelmaking is a dominant approach in North America and controlling EAF emissions is a key issue today because of stringent permit limits imposed by various regulatory bodies. In the present study, an attempt has been made to mathematically model EAF emissions, and use the models as a predictive tool for fine tuning the process. CFD modelling has been used to model various fume release scenarios, and optimize the exhaust conditions for maximum capture. Thermodynamic calculations have been used to analyze various chemical reactions which lead to the emissions of hazardous air pollutants with special emphasis on Zinc, Lead and Manganese.

Jan 1, 2015

By Ltd. (CYMCO) Technology Center Yunnan Metallurgical Group Co., S. Jian, T. Song, J. D. Miller

"As sulfide zinc ore deposits become exhausted, nonsulfide zinc ore deposits become the other resource for zinc production. However, flotation for zinc recovery from nonsulfide deposits is much more difficult than the flotation of sphalerite from sulfide deposits and may become an option for zinc production only if a suitable processing technology is developed. In this regard, research efforts are being devoted to the flotation of nonsulfide zinc oxide minerals. Some common methods which have been used for the flotation of zinc oxide minerals include sulfidization-flotation, activation, and direct flotation with anionic and cationic collectors. The traditional flotation techniques have low efficiency and difficulty in separation and recovery of the zinc minerals from gangue minerals, for example, smithsonite (ZnCO3) from other carbonate gangue minerals and hemimorphite (Zn4Si2O7 (OH)2·H2O) from silicate gangue minerals. In this study potassium lauryl phosphate was evaluated as a collector for the flotation of nonsulfide zinc minerals. Results from contact angle and microflotation experiments at pH 6–9 show that hemimorphite (Zn4Si2O7 (OH)2·H2O) can be floated from quartz and that smithsonite (ZnCO3) can be floated from calcite. However, when dodecylamine, which is a common collector reported in literature for the flotation of nonsulfide zinc minerals, was used as collector, no significant difference between nonsulfide zinc minerals and gangue minerals was observed at any pH value. Initial evaluation suggests that potassium lauryl phosphate is effective at low concentration and may be a promising collector for zinc oxide mineral flotation.INTRODUCTIONBefore the twentieth century, zinc was mainly produced from nonsulfide ores (Large, 2001; Gilg, Boni, & Cook, 2008). With the development of differential flotation processes in the late 19th century major production switched from nonsulfide zinc sources to sulfide zinc ores (Hitzman, Reynolds, Sangster, Allen, & Carman, 2003; Gilg et al., 2008). However, as it is becoming more difficult to find new sulfide ores, recovery from nonsulfide deposits is being considered. Nonsulfide flotation for zinc recovery is much more difficult than the flotation recovery of sphalerite from sulfide deposits and may become an option for zinc production if a suitable technology is developed. Zinc and lead oxide ores are difficult to beneficiate ores due to their similar floatability with gangue, high solubility in water, and the influence of slimes (Fa, Miller, Tao, & Li, 2005). In order to improve the performance of oxidized minerals, lots of effort is being devoted to this field of study (Ejtemaei & Mahdi, 2014)."

Jan 1, 2016

By David A. Summers

Historically, the presence of methane has been a problem, mainly in and around the working areas of active coal mines, and only in these area has drainage been considered. Drainage, where practical, has been achieved through the drilling of holes forward into the coal and the surrounding strata from the working area. These holes generally have been short in length, although where methane drain- age operations around a longwall face have been undertaken, the holes have had to be longer in order to adequately drain from the center of the face into the access gate roads. In recent years, attempts have been made to degasify the coal seams in advance of mining, without disruption of the mining cycle. This is done by drilling much longer horizontal holes through the coal in advance of the working area. Under the aegis of the Federal Government, methods have also been developed for draining seams of coal of their methane content in advance of mining, but from shafts sunk from the surface, without using the active area of the mine as the location for the drill holes.

Jan 1, 1979

By A. Arik

Reliable ore reserve estimates for deposits with highly skewed grade disributions are difficult tasks to perform. Although some recent geostatistical techniques are available to handle problems with these estimations, ordinary kriging or conventional interpolation methods are still widely used to estimate the ore reserves for such deposits. The estimation results can be very sensitive to the search parameters used during the interpolation of grades with these methods. This paper compares the ore reserve estimates from ordinary kriging using several cases in which certain search parameters are varied. The comparisons are extended to different mineralizations to show the changing effects of these parameters.

Jan 1, 1990

By Andrew Case

The Port Nickel facility in Braithwaite, Louisiana, is known for pioneering hydrometallurgical processes for the 'separation and recovery of nickel, cobalt and copper. Ten years ago, in 1985, a new CRI-MET process for the recovery of molybdenum, vanadium, nickel, cobalt and alumina from spent catalysts was developed and implemented. Spent- catalysts from the petroleum industry consietute the majority of feed. These are not only a valuable-source of metals, but due to EPA regulations are frequently classified as hazardous under RCRA. Molybdenum and vanadium are selectively leached in an oxidative hydrothermal step. Alumina is then extracted in a caustic digestive leach. The unique technology produces four primary commercial products l molybdenum trioxide, vanadium oxide, aluminum trihydrate and nickel-cobalt concentrate. This paper discusses the process, modifications. during ten years of operation, and the relationship of these modifications to the future of the catalyst recycling business.

Jan 1, 1995

By F. L. Bazzanella

Cyprus Pima has two concentrators, one with a conventional crushing-grinding circuit and the other using semi-autogenous grinding followed by ball mills.

Jan 1, 1978

By V 9. 0 / 300 dpi

ATHOUGH turquoise mining was, so far as we know, the first large, well-organized mining operation,' gem mining, from the Roman con-quest of Egypt until the opening of the South African pipe diamond mines some 50 years ago, was largely carried on' by individuals 01' small companies in a relatively primitive way. Now" however" gem mining does not yield in efficiency or in scale of operations to the mining of other mineral products. In 1926 the diamond mines of the world milled some 9,000,000 cu. yd. and produced 0,43 cu. yd. diamonds, a remarkable example of concentration. The Premier Diamond Mining Co. up to Oct. 31, 1927, had milled 116,455,550 loads (each of 16 cu. ft.) from which 26,-217,144 carats of diamonds" worth £29,897,971 2s, 9d., were recovered. The Burma Ruby Mines, Ltd., operating sever-al alluvial mines in Burma in 1911-12, mined and milled 1,479,845 truckloads of gemmiferous earth for 15c. per load. We of the industry can there-fore, with good grace, disclose some of the myths and also describe some of the primitive mining methods of the, dark ages of our industry. The methods, so far as I know, were not patented, and if they were, the patents have expired, so that engineers in other branches of the art are free to use them if they see fit.

Jan 1, 1928

By Ahmad Ghahreman, Denver Cowan, Yeonuk Choi

"Previous testwork by the authors has indicated that both granular coconut shell based activated carbon and a new microporous carbonaceous bead, Lewatit® AF 5, are highly effective in improving the oxidation kinetics and decreasing the elemental sulphur yield when assisting the atmospheric oxidation of pyrite. While the two carbon catalysts show similar results and improvements to the pyrite oxidation, there are differences between them. For example, the activated carbon assisted oxidation showed faster kinetics than the AF 5 assisted oxidation, while elemental sulphur seemed to remain adhered to the surface of the AF 5 after oxidation when much of the elemental sulphur formed during the activated carbon assisted tests was found in the oxidation residue. The objective of this paper is to investigate the differences between the two catalysts through the use of scanning electron microscopy, photography, Raman spectroscopy, surface chemistry analysis, and Brunauer-Emmett-Teller (BET) surface area analysis. With this investigation the authors should be able to achieve a better understanding of the surface chemistry of the two carbon catalysts (i.e. functional groups, charges, acidity etc.) and help explain the strengths and/or the weaknesses of the catalysts when applied to the atmospheric oxidation of pyrite.INTRODUCTION Previous research conducted by the authors, indicated that both a granular coconut shell based activated carbon (activated carbon) and a microporous carbonaceous bead, Lewatit® AF 5 (AF 5), acting as a catalyst enhanced atmospheric pyrite oxidation in ferric sulphate media by approximately 40% when compared to unassisted oxidation and that elemental sulphur yields were increased from 23% to approximately 69 and 63% when assisted by AF 5 and activated carbon respectively (Cowan, Jahromi, & Ghahreman, 2017). The study indicated that although total pyrite oxidation assisted by the two catalysts was similar, differences were noticed in the impact that the two catalysts had on the outcome of the oxidation. Kinetic curves in the Cowan et al. study indicated that atmospheric oxidation of pyrite seemed to reach completion after 48 hours of oxidation when assisted by activated carbon. A similar trend was noticed in the kinetic curves for oxidation when assisted by AF 5, however the oxidation curve did not reach completion until approximately 96 hours (Cowan et al., 2017). This observation indicated that the kinetics of pyrite oxidation are enhanced by both catalysts, oxidation kinetics are much faster when assisted by activated carbon rather than AF 5."

Jan 1, 2017

By Wallace R. Horn

"MR. CHAIRMAN AND GENTLEMEN :I begin this talk by making a couple of comments which are of the nature of disclaimers.Firstly, and as the Chairman has otherwise indicated, I was neither ""born into"" nor have I spent more than a few years of my professional life in the mining industry. I mention this because many might, and perhaps rightly, consider that an added qualification in presenting a report of what the industry has accomplished. Indeed, I am not here to blindly defend all of its actions and inactions in respect to environmental control over the years. Nor am I here to seek absolution of the industry's past transgressions - if indeed that is the word. Mistakes might be a better one. I concluded some time ago that the effects of those mistakes are too difficult to assess against the sea of errors of our total society. I should mention too that I am not an environmental engineer or specialist - only a portion of my interest is involved with this field. Perhaps this permits a perspective which allows a more accurate and objective view.One further comment here. My job today, as I understand it, is to generally report upon the nature and extent of the response of the metals mining industry to control of the environment. In the case of an industry operating at more than a hundred locations and for various reasons at various stages of progress, it is not an easy job. On the other hand, I wanted to avoid the use of generalities because, especially within the context of environmental or ecological opinion and of the practice of condemnation of industrial segments, I think we've had about enough of generalities until we know far more than we do.Finally, I am quite aware that a statement of future plans to achieve environmental control does not impress or satisfy as many people as it may have done some years ago. Public opinion demands to know what is currently underway, today."

Jan 1, 1972

By P. J. Coleman

Research in the field of mining safety and health in the United States plays an important part in protecting the lives of miners. The National Institute for Occupational Safety and Health (NIOSH) Mining Program conducts surveillance, studies and developmental work aimed at improving the safety and health of miners. With recent reviews of the Mining Program by the National Academy of Sciences and the Mining Program response (NIOSH, 2008), the importance of setting goals, conducting high quality engineering and scientific research and evaluating the outputs, outcomes, relevance and impacts of these projects has been reemphasized. Surveillance of reported injuries is a first step in deciding on research directions and in designing specific projects. Groups of injuries often share features and attributes that suggest common causes and may respond to similar preventive efforts. Identifying groups of injuries also serves to prioritize intervention efforts. The Mine Safety and Health Administration (MSHA) Accident and Injury database (MSHA, 2008) provides individual case reports of mining injuries, illnesses and certain no-injury accidents (events such as roof falls that stop mine production or miners? activities for more than one hour). This database is an indispensable resource for researchers and stakeholders needing information on the statistics of these events. From an epidemiological perspective, research projects target groups of miners at risk due to specific patterns of work, equipment, mine settings and the management of safety and health in their mines. Incidence rates are provided by the MSHA data for selected variables, such as surface/underground location, standard industrial classification and state. While incidence rates are the preferred measure for all variables, denominators are not typically available; for example, to more clearly under-stand the data about injury by occupational type, it would be necessary to conduct demographic surveys. A current survey of the demographics of the mining industry should be complete by 2010, which will allow incidence rates to be developed for a number of variables such as age, occupation and experience. This survey will provide the first update of its kind since the first survey was conducted in 1985.

Jan 1, 2010

By C. E. "Sam" Lovewell

In approaching a discussion of production of cement, I hope I won't be like the porter in the bank who was asked if he could give some details on the rediscount rate. He replied, "Boss, when I said hello, I told you all I know." Need for change every so often is illustrated by the story of the little boy four years old who had not spoken a word in those four years. One morning he said, "This damned oat meal is burned'." His Dad was amazed and said, "Son, how come you haven't said a word for four years and now out of a clear, blue sky you say, "The oat meal is burned." Johnny said, "Well, up to now everything has been all right." Not being a mining engineer myself, and my subject not dealing with mining engineering directly, I can only hope that you will agree that the subject has current relevancy by the feet that it can materially improve our environment by putting to good use a potential environmental polluter; namely, fly ash. The profitable utilization of fly ash can reduce cost of use of coal as an energy source. Therefore, it behooves us all to explore to the greatest depth, the pluses and minuses occasioned by its use wherever possible. My particular subject and my particular interest lie in its utilization as a blend in the production of Type IP Portland-Pozzolan Cement meeting requirements of ASTM C-595, Type IP.

Jan 1, 1974

By Christopher J. Brown

"Proper ground stability in gate roads has been a critical aspect of success in longwall mining. In particular, the tailgate has proven to be one of the more active mine areas that needs to be managed (Barczak, Dolinar, and Mucho, 1999). As longwall tailgate support technologies continue to be developed and improved, Strata Worldwide has worked to design and manufacture a revised Propsetter to provide additional support capacity and enable applications at greater mine heights. The support is targeted for tailgate applications; however, it can also be used for roof support in various types of mining environments. This paper describes the design changes for enhancing the support capacity of the Propsetter to more closely align its performance with other support technologies currently being employed in longwall tailgates. Balancing changes to each design aspect of the Propsetter was key to successfully improving the roof support load capacity while maintaining controlled deformation. Increasing the load capacity would allow a mine to improve support efficiency with a smaller, less intrusive support compared to support alternatives and to reduce the cost per foot of supported entry. The target support capacity was 80 to 100 tons at two inches of deformation to more closely match the performance of competing tailgate supports, such as the 24-inch-diameter CAN®. To achieve this goal, changes were made to all design aspects of the Propsetter: diameter, wedge cut depth and angle, pod size, and confinement rings. Test results from the NIOSH Mine Roof Simulator verified that these design changes were successful in increasing the capacity of the Propsetter to the 80- to 100-ton range at two inches of deformation. INTRODUCTION Roof support is one of the most fundamental elements of the underground mining process. As materials are removed from the earth, geological conditions will almost always require some form of roof support to keep the extraction area open and stable. Coal mining environments often experience difficult geological conditions that require both primary and secondary forms of roof support to keep the mining environment safe and economical. The secondary support system serves as additional support in the case the primary support system is inadequate. If designed properly, the secondary support system will also assist in maintaining integrity of the immediate roof beam (Barczak, 2000)."

Jan 1, 2017

By Todd Schrauf, James Scott, Mark Smith

"Cyanide heap leaching of gold ores in areas with extremely low winter temperatures requires special considerations to prevent freezing of the leach solution. Factors that impact the solution temperature include ore temperature at the time of stacking and during operation, burial of drip irrigation lines, use of geomembrane covers and heating of the leach solution. Thermodynamic modeling was performed to simulate expected ore and solution temperatures under different operating strategies for Kaminak Gold’s Coffee gold project in the Yukon Territory. Mean monthly temperatures at the site ranged from a low of -22.5 °C (-8.5 °F) to a high of 13.6 °C (56.4 °F), while in situ ore temperatures ranged from -0.5° to about -1.5 °C (31 ° to 29 °F). The modeling results were used to optimize the operational parameters and indicated that a combination of drip line burial and heating of the leach solution during the winter months was required to maintain solution temperatures above freezing during the initial years of stacking, although as the size of the heap increased, heating was no longer necessary.Modeling objectivesThe successful operation of a cyanide heap leach under extremely cold winter temperatures requires the implementation of operational strategies to prevent freezing of the leach solution and the ore within the heap. Thermodynamic modeling of the heap provides the means to quantify the effectiveness of these different operational parameters on maintaining the required operating temperatures to avoid freezing within the heap. The operational parameters that were evaluated with the model included:"

Apr 1, 2016

By Lewis Carroll

AS he contemplates the numerous good things the hard-working committees have evolved for the 140th Meeting of the Institute, the Editor knows just how the walrus felt when he uttered his memorable, if somewhat lugubrious lines. For there are the Annual Reception and Dinner at the Commodore, 'the Gold Supply Symposium, the luncheons, general and special, and the Annual Institute of Metals Lecture, a Round Table on Iron Ore and a wonderful Informal Dance at the Grand Central Art, Gallery, substantial general sessions, a Smoker-and many other things. -Old, friends and new, reminiscences and confidential chats, horizons pushed back by new information and adjusted perspectives, courage revived and ambitions stimulated-one with a flair for the modernistic might make something-or nothing-of the kaleidoscopic preview 'of the coming Annual Meeting.

Jan 1, 1931