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By R. Loney, M. Militzer

There is a significant demand for new high strength steels with fine grain sizes for structural applications. One approach in this regard is to develop hot-rolled HSLA steels where refining the microstructure leads to increased strength levels, e.g. 700 MPa yield strength, that can be attained by suitable modifications of chemistry and processing. Here, an HSLA steel is investigated that contains 0.05wt%C-1.65wt%Mn-0.20wt%Mo¬0.07wt%Nb-0.02wt%Ti and approaches the above strength class. The ability to control and predict the mechanical properties of hot rolled steel depends strongly on the thermomechanical processes, which the steel undergoes. The final microstructure and, thus, the properties of the hot-rolled steel are a function of the austenite decomposition obtained during accelerated cooling on the run-out table and precipitation during coiling. The austenite-to-ferrite phase transformation under run-out table conditions has been investigated using a Gleeble 3500 thermomechanical simulator equipped with a dilatometer. The effects of cooling rate and initial austenite microstructure including the degree of work hardening on austenite decomposition kinetics and ferrite grain refinement have been quantified. Results show that grain refinement can be optimized by the presence of work hardened austenite and accelerated cooling. Based on the experimental results, a model is proposed to predict the transformation start temperature and the resulting ferrite grain size for run-out table cooling conditions.

Jan 1, 2004

By W. K. Collins, C. L. Dahlin, D. C. Dahlin, W. K. O’Connor, G. E. Rush

Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results have been achieved using heat pretreated serpentine feed material and high partial pressure of CO2 (PCO2). Specific conditions include: 155°C; P002=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy has been utilized to investigate the appropriate feed characteristics, identify the process products, and interpret the mineral dissolution and carbonate precipitation reaction paths.

Jan 1, 2001

By Carl Zapffe

JUST as 85 per cent of the total ore produced annually in the United States comes from the Lake Superior region, so does one of its six producing districts-the Mesabi --dominate that region both as to production and total reserves; also in ore Treatment, Mesabi practice is dominant. Therefore, in discussing future reserves or ore treatment one may visualize one big district with five smaller districts as so many satellites. In considering the future less thought need be given to processes than to, economic policies. For thirty years experimental work has now been in progress and every possible ore-treatment process now known has been given attention. This work was started when there was no recognizable danger of running short of ore because of rapid consumption. Thirty years ago the annual production had just progressed beyond the twenty-million bracket for the first time. Today fifty million tons is considered a small production, and last year the aim was for 65 million. At the recent rate of production the life of the estimated reserves of good ore is about 35 years. All who know the local terrain are convinced that, unlike thirty years ago, the chances for discoveries of new big deposits are nil; treatment of lean ores obviously is to become an all-important topic.

Jan 1, 1938

By C. O. Bounds

Management of emission control dust from electric? arc furnace (EAF) steelmaking as an RCRA-EPA listed hazardous waste places economic and environmental pressures on the steelmaking industry. Horsehead Resource Development Company, Inc. (HRD) serves the industry by recovering nonferrous metals from the dust in rotary kiln plants in Palmerton, PA and Chicago, IL, and has demonstrated the commercial viability of its patented coal-fired FLAME REACTOR Process. However, because of location and/or regulation, many steelmakers could be more economically served via on-site processing of its dust. Therefore, in 198-7, through a contract with the Gas Research Institute, HRD embarked on a program to develop a gas-fired reactor and test a prototype unit. The development program has successfully proven the environmental, technical and economic performance of the concept. Consistently high zinc, lead and cadmium recovery to an oxide concentrate as well as production of a nonhazardous, delistable slag have routinely been achieved. The gas-fired FLAME REACTOR field experiment results and the economic performance of on-site or smaller regional plants will be highlighted.

Jan 1, 1990

By John W. Buch

IN my review a year ago I pointed out that a small coal-mining companies as well as large had decided that the so called ?central shop? was a benefit. These central shops replaced in a large measure the commercial shops operated by those who have no direct connection with production of cod. Central shops in this time of salvage and major repairs have proved their worth. In addition, many of the larger companies had in their central shops equipment available for the production of many thousands of parts for our vast war machine and, as subcontractors, are doing this type of work. This is a real contribution to the war endeavor. Lack of new supplies has resulted in exhaustion of those stocks formerly stored or hidden in underground shanties. This means that the small stock of repair parts likely LO be available to any mine

Jan 1, 1943

By Diego Marquina, Jorge Terrones, Jose Morales

Si bien los incendios en el sector minero representan apenas el 1 % del total en todos los sectores, sus consecuencias son potencialmente críticas, por lo que resulta necesaria una evaluación constante de riesgos de incendio. En una evaluación de riesgo de incendio convencional (FRA, por sus siglas en inglés) se detallan los escenarios de riesgo de incendio a los cuales está expuesta una unidad minera, considerando las condiciones de la instalación, el análisis de los procesos, identificación de actos y condiciones subestándar, equipos u operaciones, reportes de incendio o amagos, entre otros factores que permitan identificar y analizar los escenarios de riesgo de incendio para definir su nivel de criticidad y aceptación del riesgo. Este enfoque diferenciado de FRA busca priorizar la inversión en protección contra incendios, al tomar en cuenta una tolerancia específica al riesgo de incendio, vida útil de la mina y la continuidad de procesos o recursos críticos para la operación en un nivel mínimo tolerable.

Sep 20, 2019

By J. K. Weglo, M. U. Savich

"The measurement and evaluation of the noise emanating from an ST4A scooptram in an underground stope under a simulated work cycle, and under three conditions of after-treatment systems is covered.These include scooptram without muffler or filler (bare engine), an in-line small filter, compared to a larger-filter, and the larger filter with an in-line muffler in series with fume diluter, which were tested under three engine operating conditions-IDLE, wide open throttle (W. 0. T.), and working condition. This is load, short haul and dump operation.The results showed an attenuation of the scooptram at work of 8 to 15 dBA, 16 cm from the exhaust pipe of the machine, to 4.8 dBA at the operator's ear. Recommendations are made to increase the attenuation at the operator 's ear by additional improvement in design of the fume diluter.IntroductionIn current mining operations, the diesel engine provides a safe, efficient and highly mobile source of power. In the major underground mine s in Canada the most common types of diesel equipment are load-haul-dump (LHD) machines and ore trucks. In general, there is a tendency to use high horsepower, diesel LHD machines in mines to achieve maximum productivity. The increased use of diesel-powered equipment in underground mines has shown no cause pressure levels were measured at the exhaust and outlet pipe. Also, while measuring the octave band and A-weighted sound pressure levels, the operator's position was also measured."

Jan 1, 1986

By M. M. Monte

A method for removing metallic mercury from contaminated tailing, using the flotation process, is described. In order to define some relevant parameters for the mercury flotation system, microflotation and electrophoretic mobility tests were carried out on (pure) metallic mercury in the presence of several surfactants. Based on the results obtained from fundamental studies a series of bench scale flotation experiments with mercury containing tailings from two wetland sites in Brasil were done. The results of microflotation tests with mercury showed that by using cetyl trimethyl ammonium bromide, an increase in mercury flotability is observed in the acid pH range, whereas in the presence of potassium oleate the highest mercury flotability was found in the alkaline pH region. The mercury flotability using potassium amyl xanthate was improved by the addition at sodium dithionate as an activator. The bench scale flotation tests with contaminated tailings from Poconé (brazilian wetland site) showed a recovery of 70% when sodium dithionate was used as activator and potassium amyl xanthate as collector. The resulting coefficient of separation is around 60%. However, the results of the flotation experiments with fine fractions from amalgamation tailings from Peixoto de Azevedo (brazilian wetland site) showed a low mercury recovery (32%).The results from this work suggest that since in the Poconé site tailings, the metallic mercury is not completely associated to the finer particles, the flotation process to recover the metallic mercury seems very promisor.

Jan 1, 1996

By F. A. Myzenkov

The technology developed by the authors uses new methods for raw material smelting in electric furnaces, a new autogenous method and apparatus for subliming smelting for antimony trioxide production and separation of antimony and gold. Concentrate produced from the ore deposits in Yakutia has the following average contents of main constituents, % by weight: 29.4 Sb, 1.2 Fe, 13.1 S, 40.0 SiO2, 0.2 As, 2.6 CaO and 45 g/t of Au. Unlike the technology used abroad a new autogenous method makes it possible to increase considerably specific capacity and reduce gold losses with antimony trioxide by several times. At the same time mineralogical composition of trioxide has improved considerably ? it has mainly a cubic base with prevalence of senarmontite. The content of a main component (Sb2O3) in the final product has increased from 99.0% up to 99.6% which means better quality and makes it suitable for use in special technologies. Despite a lower antimony content of the concentrate (29.4% as compared with over 33% as common in the world practice), an antimony recovery of 85.3% into a commercial-grade product has been achieved, as well as a gold recovery of 96.65% into a gold-antimony alloy. The technology for processing gold-antimony materials developed and introduced at the Ryaztsvetmet plant is unique in the world with respect to gold recoveries.

Jan 1, 2006

By F. F. Peng

For a given flotation system, the rate-controlling step in fine coal flotation can be the attachment of bubble to the fine coal particles. The probability of attachment depends upon the surface characteristics and the collector adsorption on the coal particle surfaces. Thus, to further improve the flotation rate and selectivity is to alter the distribution of hydrophobicity on coal particles efficiently by applying the effective means of collector dispersion. In order to enhance the combustible recovery and selectivity of fine coal flotation, and lower the amount of collector used in the fine coal flotation processes, four modes collector dispersion/addition techniques are tested. They are direct liquid addition in pulp (mechanical agitation), ultrasonic energy dispersed collector into pulp, atomized collector into pulp and gasified collector transported by air and formation of collector-air bubbles in pulp. The effect of four collector dispersion/addition methods on the floatability of -600 µ m (-30 mesh US sieve) coal samples from four ranks of coals were studied. The ultrasonic energy dispersed collector and atomized collector flotation processes enhance flotation yield and most significantly improve the kinetics of fine coal flotation. The gasified flotation process can increase the selectivity of separation and decrease the collector consumption due to starvation flotation is achieved in this process. The flotation efficiency of gasified collector process is as high as that of conventional flotation. It is because that the effect of the decrease in the combustible recovery is offset by the increase of selectivity. In addition to flotation experiments, induction times of bubble attachment to the bed of fine coal particles for four ranks of coals are measured.

Jan 1, 1992

Maps and Mining Data for the Library. I suggest that the Institute Library can increase its usefulness by systematically soliciting from the engineers and mining companies all published reports and maps, and parts of reports and records, not of a private or confidential nature. If this is done an engineer assigned to report on a well-known property or district may depend on finding at the library a large amount of preliminary data and general information from these official and engineering reports relating to his prospective investigation. In many mining reports a large part of the report is of a general technical and scientific character, and there could be no good objection on the part of either the engineer, or his client to making such information thus of record. I believe there would be a great deal of information furnished by the engineers if they were properly solicited under this plan. I have found on different occasions that much work could be saved by such records now in the Library. The plan would also have the advantage of keeping the Library in closer touch with the active engineers, a feature to be desired. I also have in mind that the Library should undertake to collect all the prospectuses and financial literature which is issued in connection with mining. Of course a great deal of this is unreliable, but even this is valuable for record in the matter of legal and other investigations. I shall be glad to co-operate with you, and do anything I can to develop more in detail the general ideas above noted. Yours very truly, KIRBY THOMAS NOTE.-The Library of the Institute makes a specialty of collecting and filing material of this character, and the letter printed above is brought to the attention of members in the hope that they will co-operate by sending in copies of maps, reports of properties, etc.

Jan 11, 1913

By James W. Niehoff

"Prior to 2003, most high rise structures in Honolulu, Hawaii were supported on driven pile foundations, extending through shallow coral strata and bearing in competent formations at depths of 100 ft (30 m) or greater. In 2003, the 40-story Hokua Tower became the first building in Hawaii to use continuous flight auger (CFA) piles for support. These piles derived most of their capacity from side shear in the shallow coral formations, which reduced their required lengths to less than 100 ft (30 m) sand significantly increased their capacity. Not only did CFA piles prove to be more efficient and cost-effective than driven piles, but the reduced noise and vibration associated with their installation made them and drilled piers the foundations of choice for most mid- to high-rise projects going forward. Because drilled foundations were new to Hawaii, it was necessary to develop effective design parameters for the unique soil and rock conditions found within this urban area. While drilled foundations were found to have many advantages over driven piles, construction techniques had to be modified to compensate for extensive voids in the coral formations. This paper presents a compendium of the data derived from numerous full scale, instrumented load tests conducted during the past decade and provides guidance for the design and installation of CFA and drilled pier foundation systems in areas having geologic settings and history similar to that of Honolulu.INTRODUCTIONThe State of Hawaii is one of the most remote areas in the world, lying nearly 2400 miles (3800 km) from the nearest continental land mass. In spite of this vast distance, the population of the islands has grown to over 1 million people, the majority of whom live within and in close proximity to the City of Honolulu on the Island of Oahu. The city is densely populated with over 400 high rise apartments, condominiums, hotels and office buildings located within 5 miles (8 km) of the city center (Fig.1). Nearly all of these buildings have been constructed within the past 50 years."

Jan 1, 2016

By Arthur P. Sanda

Thank you Clark, for that extraordinary introduction, but Paul Harvey would be disappointed if I didn't tell you ... the rest of the story. It's true that I began my career at the Boston Traveler newspaper, one of the last of the breed that started as an office boy and eventually advanced to staff reporter. However, what the biography doesn't tell you is that after that stellar rise to prominence in the Boston financial community, the afternoon Traveler was merged into the morning Boston Herald, and I was out of a job. Between the Traveler - which I closed - and the Brockton Enterprise - where I helped bring about the first labor strike in the newspaper's 100 year history - for a short period I worked double shifts at a bomb factory where we made beanbag mines for use in Vietnam. That is until the plant blew up one morning between my shifts - my last shift, as you can guess. Incidentally, my job was quality control. Before accepting my first public relations job with Boston Gas Company - and handling the media during that companies longest strike in history - I worked part time as a police officer in the small Massachusetts town of Halifax, during which time I wrecked the town's only patrol car - twice. Having contributed all I could to Boston Gas Company, I moved on to the parent company - Eastern Gas and Fuel Associates - where I was instrumental in closing down the last remaining coke plant in the Northeast in the Bridesburg section of Philadelphia - and got my first exposure to the coal industry - a visit to Eastern's last two coal mines in western Pennsylvania, Culver and Delmont - which were closed a month later. With the coal boom at its apex in the late '70s, the bosses thought it would be safe - and safer for the other subsidiary companies - for me to be given the opportunity to establish a formal public relations department at Eastern Associated Coal Corp. In my 10 years with Eastern Associated, I was able to help take the company from 17 operating mines down to 6, from 8 longwall sections down to 5, and eventually have the entire company sold to Peabody, While at the same time, bringing an end to the coal boom. It was at this point that journalism again beckoned, which coincided with COAL magazine purchasing Coal Age from McGraw Hill Publishing. In my l l years with the magazine, we've taken it from Coal Mining and Processing, to Coal Mining, to just COAL, and back to Coal Age - which is the best thing we ever did - and we've had the company sold ... twice.

Jan 1, 1999

By Jerry E. Olson

In 1988, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied additional areas, encompassing 11,303 acres, on the east and west sides of the 20,727-acre Badlands study area (Olson, 1987) in order to evaluate their identified mineral resources. The Badlands study area additions are located in Crook and Deschutes Counties, OR, about 10 and 18 miles east of Bend, OR. No mineral resources were identified. The additional areas studied are underlain by Tertiary-and Quaternary-age basalt flows which are largely covered by a veneer of sand and silt. No mines, prospects, mining claims or mineralized areas occur within or near the Badlands study area additions. Slab lava of marketable grade and quantity was not found in either area. None of the study area is of current interest for geothermal resources, but the eastern study area addition has been leased (1984) for oil and gas.

Jan 1, 1989

By J. A. Bleeck

A discourse on the relationship between industrial minerals and paper production, concentrating on high grade, ultra fine ground calcium carbonate (mean particle size less than 2 microns) and precipitated calcium carbonate. The scope of the paper encompasses four basic areas relevant to the topic: 1. A tutorial overview of the papermaking process with an examination of various industrial mineral components in that process; 2. A discussion of basic technological topics pertinent to the utilization of carbonate in paper with emphasis on the relative aspect. Of natural ground calcium carbonate (GCC) and synthetic precipitated calcium carbonate (PCC); 3. An overview of paper and carbonate market, in both the United State, and Europe with emphasis on (a) current status and future growth trend. Of such market., and (b) discussion of the major influences on growth and development of such market.; and 4. Identification and discussion regarding the principal producers in calcium carbonate markets serving the paper indu.try in Europe and North America.

Jan 1, 1993

By Bidwell TJ, Servant S

Paste back-fill technology is gaining rapid acceptance in the Canadian mining industry. The authors were able to work on four different mining sites employing paste technology in their operation. In each site the paste hackfll is prepared with very fine tailings containing significant amounts of sulphur minerals. The research program involved laboratory testing on samples prepared in the laboratory, on control samples obtained at the hackfilll plant during pouring into the stopes and on core samples obtained from drilling in backfilled stopes. The laboratory testing provided detailed knowledge of the mechanical behavior of the paste backfill. The need for a means of measuring the in-situ mechanical properties of the backfill became clear. A review of various trials published in literature and an evaluation of available technology suggested the Cambridge Self-boring Pressuremeter. A first field campaign confirmed the efficiency and dependability of this instrument leading to the conclusion that it offers a very good method for the in-situ measurement of paste backfill properties.

Jan 1, 1998

By A. A. Brant

BECAUSE of its simplicity, the dip needle is widely used for locating magnetic rock formations in drift-covered areas. Although it responds only to strong magnetic disturbances, it has the advantage that surveys with it can be carried out rapidly, at relatively low cost, by untrained operators. More accurate surveys can be made with a much more sensitive instrument known as the magnetometer, but this must be operated by a specialist and the resulting survey costs are much higher. Mining men use the dip needle for the location of magnetic ores or mineral deposits associated with magnetic rocks. In certain districts, a survey with the dip needle may aid in solving geological structure. In the Little Long Lac and Crow River gold camps of Ontario, it has recently been used for these purposes. In interpreting the results of a dip needle survey, an understanding of the chief magnetic and mechanical factors determining the dip recorded by the needle is definitely necessary. For example, many observers locate a magnetic body by the highest dip values, apparently unaware that these frequently may not lie directly above the body. It should also be realized that a careful dip needle survey may yield information regarding the dip, breadth, and perhaps depth, of the magnetic body. Moreover, the observer should know when numerous closely-spaced dip readings are necessary, and when the dip may be measured at more widely separated intervals. The purpose of the following article is primarily to describe the factors affecting the registration of the dip needle, with a view to aiding investigators in a more accurate and complete interpretation of their results. To explain the cause of magnetic disturbances (anomalies) and the action of the dip needle, a knowledge of certain fundamental magnetic terms is necessary.

Jan 1, 1938

The following letter has been received from the Chairman of the United States Shipping Board. August 1, 1918. American Institute of Mining Engineers, New York, N. Y. GENTLEMEN: I am going to call upon your organization for some teamwork. The time has come for Americans everywhere to put themselves solidly behind American ships. Our railroads must no longer stop at the ocean. We are building an American merchant fleet of twenty-five million tons-three thousand ships. We are backing modern ships with modern port facilities, establishing our bunkering stations all over the globe and will operate with American railroad efficiency. We will carry American cargoes at rates corresponding to our railroad rates-the cheapest in the world. Fast American passenger-and-cargo liners will run regularly to every port in Latin America, the Orient, Africa, Australia. Are you taking steps to use these ships to increase your own prosperity? Do you realize that American products of factory, farm and mine can be delivered to customers in foreign countries on terms which will build lasting trade? Do you realize the possibilities for bringing hack raw materials to extend your products and trade? We must all take off our coats and work to bring these American ships home to the people of every American interest and community. The manufacturer must think of customers in Latin America as being as accessible as those in the next state. The farmer must visualize ships carrying his wheat, cotton, breeding animals, dairy products and fruit to new world markets. The American boy must think of ships and foreign countries when he chooses a calling.

Jan 9, 1918

By Y. H. Zhan

A new P(MAAA) latex was developed and used in separation of ultrafine apatite from calcite and silica by means of selective flocculation. The latex was found to flocculate selectively apatite from apatite/calcite and apatite/silica mixtures in the presence of sodium tripolyphosphate and sodium silicate over a pH range from 9.1 to 9.4. The separation of apatite from calcite was more selective with sodium tripolyphosphate, while the results of the separation of apatite from silica were better when sodium silicate was used. In the apatite/calcite system, 90% apatite recoveries into a concentrate containing 34% P2O5 were possible in the presence of 4 mg/l of sodium tripolyphosphate at a latex dosage of 2.2 kg/t. In the apatite/silica system, 80% of apatite could be recovered into a concentrate containing 33% P2O5 in the presence of 20 mg/l of sodium silicate at a latex dosage of 1.1 kg/t. Deposition tests were used to study the interaction between the latex and the mineral surfaces. The results revealed that deposition density of the latex on apatite was higher than on calcite; the differences between the deposition onto these two minerals were higher at pH 9.2 than at 7.2. The results point to the stronger interaction between the latex and apatite surface when compared with the latex-calcite interactions.

Jan 1, 1998

By W. H. (Bill) Jay

The destruction of cyanide creates a significant impost on the financial returns of gold mines. These losses increase substantially when ores containing cyanide-soluble copper are treated. Failure to remove or destroy free or WAD cyanide before it is discharged into tailings dams has, on a number of occasions, led to significant fish, bird and animal deaths. Thus, the retention of cyanide within the leach circuit and the recovery or removal of stable metal cyanide complexes needs to become standard practice for all gold mining operations. Furthermore, reducing cyanide purchases will minimise the quantity of cyanide transported to the mine site thereby reducing the opportunity for spillage of this chemical. Many different physical and chemical methods have been investigated for the removal of cyanide from process solutions. All cyanide destruction methods create a financial impost on the economic viability of the gold mine. To reduce these costs, the recycle of cyanide and the economic recovery of the metals solubilised by cyanide is of prime importance. The alternative methods currently in use, or under consideration for the treatment of copper cyanide, entail high reagent costs, produce the recovered metal in a contaminated form and require the safe handling of hydrogen cyanide. These processes will be briefly discussed within this report Environmental and financial benefits are enhanced by recent laboratory and pilot plant studies conducted by Oretek Limited. The Oretek CPC process for the recovery of copper and the recycle of cyanide from copper cyanide-containing solutions does not require pH adjustment to the alkaline cyanide leach conditions. Copper ions are coordinated to a water-soluble and/or an organic soluble polychelating agent under alkaline conditions and the cyanide ions are displaced Membrane separation, or phase separation of the polychelated copper from the cyanide ions enables the cyanide ions to be recycled and the copper to be directly electrowon from the polychelating polymer. The polychelating polymer is then recycled. Ion exchange resins and solvent extraction systems which may be incorporated into the above process will also be discussed in detail.

Jan 1, 1998