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By L. T. Matthews, C. E. Loo

During sintering, porous ore particles are easily assimilated by liquid melt. Two simple models of the process are considered: the dissolution of a solid by a liquid and the penetration of a liquid into a porous solid. Laboratory sintering studies covering a range of experimental conditions were undertaken to characterise the assimilation of large particles of ore and flux by melts formed from different mixes of fines. For ores, the process appeared to be complicated by the detachment of fines from the ore surface prior to melt formation, according to the mass of adhering fines and surface roughness of the particle. This delayed the onset of assimilation and sometimes reduced it, although melt penetration was fast and effective. Studies using different temperature profiles suggested that the assimilation of haematite was controlled by the transport of Fe2O3 away from the surface of ore particles. The assimilation of limestone depended more on thermal conditions than on the three magnesia-bearing minerals considered. Changing the composition of the initial melt significantly altered the extent of assimilation of ores and limestone, but again had a less marked effect on the magnesia-bearing fluxes.

Jan 8, 1992

By Thiago Pinto Silva

A Usiminas implementou dois ensaios para caracterização de minérios de ferro na sinterização, intitulados assimilação e penetração de fase líquida. O primeiro tem como objetivo avaliar as fases mineralógicas, a formação de poros e a resistência mecânica de partículas nucleantes e aderentes por meio da reação do minério com o calcário. O segundo objetiva medir o comprimento da penetração da fase líquida formada entre a calcioferrita e o minério. No presente trabalho, são descritas as principais características e potencialidades desses novos testes, os quais foram utilizados para a avaliação do comportamento metalúrgico de seis minérios distintos. Os resultados obtidos de assimilação e de penetração da fase líquida foram comparados com as características mineralógicas e químicas dos minérios, sendo observada uma boa correlação entre essas características e os resultados dos novos testes. Verificou-se também que a análise tradicional do minério não é suficiente para estimar seu comportamento metalúrgico na sinterização, o que reforça a importância da utilização dos novos testes implementados. Além disso, permitem avaliar o comportamento dos minérios em altas temperaturas, auxiliando na escolha da carga de minérios mais adequada para a sinterização.

Aug 1, 2018

At a meeting of the Associated Engineers, with Columbia Section in charge, a discussion of the metric system was led by-Mr. F. A. Ross. While the majority of the engineers present favored resolutions seeking compulsory adoption and use of the system at the end of 1924 it was believed the engineers present should not undertake to speak for the entire membership and upon suggestion of Mr. J. B. Fisken the resolutions were laid over to be acted upon at a later meeting. The resolutions are as follows: WHEREAS the Great War has drawn the United States into a permanent and close relationship with the other nations of the world and opened the way to an unlimited foreign trade; and WHEREAS more than-70 per cent. of all nations have discarded their arbitrary standards of weights and measures and have made the use of the decimal, or metric, system obligatory; and WHEREAS the United States still clings to an antiquated, complex, cumbersome, and wholly illogical system of weights and measures, consisting of a duodecimal and fractional arrangement of arbitrary units, instead of definitely determined and correlated units following the decimal system; and

Jan 8, 1919

By Ashis Bhattacherjee, Rahul Upadhyay, Nearkasen Chau, Aditya Kumar Patra, Dhanjee Kumar Chaudhary

Heavy earth-moving machineries used in openpit mines intensively expose drill operators to whole-body vibration and shocks, and thus to musculoskeletal disorders. The roles of individual, machine and rock-related factors in their exposure remain poorly understood. This cross-sectional study investigated their roles in 39 drill operators from Indian iron ore mines. It shows that 70 percent of the operators were exposed to high levels of vibration, above the limit values recommended by ISO 2631-1 (1997). Multiple linear regression models showed that the whole-body vibration and shock exposures were strongly associated with operator’s age, drill-machine model and rock hardness, uniaxial compressive strength and density. The role of body mass index was close to significance (p = 0.08). Univariate analyses found the drill’s age, seat-pad thickness and seat backrest height were also strong predictors. These results help in identifying risky operators, materials and occupational situations, and in implementing appropriate prevention and intervention strategies to reduce and monitor the exposures and health risk. In addition, during the planning stage of acquisition of new equipment, anthropometric data of the operators should be considered for the ergonomic design of the seat.

By Ashis Bhattacherjee, Rahul Upadhyay, Nearkasen Chau, Aditya Kumar Patra, Dhanjee Kumar Chaudhary

Heavy earth-moving machineries used in open-pit mines intensively expose the drill operators to whole-body vibration and shocks and thus to musculoskeletal disorders. The roles of an individual, machine, and rock-related factors in their exposure remain poorly understood. This cross-sectional study investigated their role among 39 drill operators from Indian iron ore mines. It shows that 70% of the operators were exposed to high levels of vibration, above the limit values recommended by ISO 2631-1. Multiple linear regression models showed that the whole-body vibration and shock exposures were strongly associated with operator’s age, drill machine model, rock’s hardness, uniaxial compressive strength, and density. The role of body mass index was close to significance (p = 0.08). Univariate analyses found that drill’s age, seat pad thickness, and seat backrest height were also strong predictors. These results help in identifying risky operators, materials and occupational situations, and in implementing appropriate prevention and intervention to reduce and monitor the exposures and health risk.

By J. Lorengo, C. H. Bucknam

"Standardization of the Inductively Coupled Plasma Mass Spectrometry (ICPMS) method for gold in cyanide solutions was undertaken to provide a more sensitive method to quantify the gold content than the atomic absorption method standardized in 1994 (E1600). The gold concentration range covered is from 0.001 mg/L Au - 0.3 mg/L Au (0.00005 toz/t Au – 0.009 toz/t Au). Interlaboratory testing was carried out with the assistance of the American Society of Testing and Materials (ASTM) International on two committees to determine the within laboratory and between laboratory reproducibility. Three barren solutions from metallurgical operations were measured in triplicate to satisfy statistical requirements for Committee E1 on Analytical Chemistry of Metals, Ores and Related Materials. A synthetically prepared matrix representing the metallurgical processing solutions was used to prepare Youden pairs to satisfy the requirements of Committee D19 on Water. Results of the standardization program are presented. INTRODUCTION Analysis of process solutions for gold concentration requires accurate and sensitive analytical methods in order to manage process control and metallurgical accounting. Flame atomic absorption spectrophotometry (FAAS) has been the work horse of the assay lab for this duty for decades. In 1994 the FAAS standard method was approved by the American Society for Testing and Materials (ASTM) (1). Six process solutions were collected and preserved by measuring the pH and adjusting to greater than pH 10, if necessary. Duplicate solutions were provided to eight laboratories in random order for analysis by FAAS covering the gold concentration range of 0.19 µg/mL (0.006 toz/t.) to 10.7 µg/mL (0.312 toz/t). A high precision method was used, which involved bracketing the sample with the higher and lower standards nearest to its concentration repeating readings three times and averaging the results. The optimum precision for the FAAS gold method was found to be at the 1.00 µg/mL (0.029 toz/t) and lower scope limit 0.3 µg/mL (0.009 toz/t) gold concentration. Since tailings solutions typically have concentrations below the lower scope limit, use of ICPMS was developed at Newmont USA Limited (Newmont) to assay the lower range solutions."

Jan 1, 2016

By C. H. Bucknam

Classical acid-base accounting using modified Sobek titration methods has resulted in interpretation of results for materials with neutralization potential (NP) less than 20 tons of CaCO3/1000 tons of material (2% CaCO3) as "uncertain" due to lack of sensitivity within that content range. Standardization of a "fizzless" acid neutralization potential (ANP) method was undertaken in the American Society for Testing and Materials (ASTM) International using two ranges of sulfuric acid additions based on reaction pH and carbonate carbon estimates rather than subjective fizz testing as well as hydrogen peroxide additions to correct for mineral acidity. The method is identified as the acid neutralization potential acidity (ANPA) titration method. During interlaboratory testing a positive bias was discovered within the "uncertain" range which was further investigated and resolved by increasing the test sample weight from one to five grams for samples needing improved accuracy in materials with ANP <2% CaCO3. Test results from the interlaboratory testing of the low range method is presented and compared with the results from the original ANPA method in the paper.

Feb 27, 2013

By Diógenes Uceda

"El presente texto revisa los problemas medioambientales relacionados con la hidrometalurgia. Las operaciones de hidrometalurgia tienen el potencial de impacto sobre el medio ambiente puesto que utilizan productos químicos tóxicos tales como ácidos, bases y agentes complejantes como el cianuro. Asimismo, los residuos de lixiviación son generalmente metaestables y bajo almacenamiento producen grandes cantidades de lixiviados contaminantes en condiciones de alta pluviometría. En ese sentido, el objetivo del metalurgista es diseñar procesos que maximicen la estabilidad de los residuos sólidos, mientras se minimiza o elimina la emisión de especies químicas perjudiciales en los flujos de agua descargados de las plantas de procesos."

Sep 1, 2016

By A. Pearson, F. A. Auld, S. O. Colbeck

"""The theory of buckling of shafts and Steel tunnel-linings"" was published by E. Amstutz in 1970 and commented on by S. Jacobsen in 1974. The authors have revised and enhanced Amstutz’s work to address Jacobsen's comments on its limitations and to extend its validity over a wider range of pipe/shaft geometries, including those commonly found in deep mine access shafts. The author has looked at Amstutz’s assessment of strengthening with flexible shear anchorages and adapted the theory of non-linear shear deformation response of bolts to develop a method of assessing increased buckling capacity utilising the full plastic shear capacity of studs. INTRODUCTION “Amstutz Buckling” refers to the buckling of pipe embedded in concrete under external uniform pressure. In terms of a mining environment, this relates directly to the design of a watertight shaft. This load case will commonly occur where a main shaft is cast against a geostatically stable primary liner and the only load applied to the final shaft is that of a uniform ground water load. Ernst Amstutz wrote his first paper on buckling of pressure-shaft steel linings in 1950 and subsequently improved his theory (Amstutz, 1970), which was then widely adopted for use within the industry. Years later, an alternative approach (Jacobsen, 1974) was proposed. Within his paper Jacobsen critiques Amstutz work, identifying some mathematical inconsistencies and highlighting limitations of the theory imposed by approximations adopted by Amstutz. Despite these limitations Amstutz work has still been used as the favoured design theory for use in the mining industry. In reviewing this body of work the author realised that with the advent of readily available computing software it was possible to adopt an iterative approach using Amstutz approximate formulae to find a solution to the original precise formulae, thus eliminating the limitations highlighted by Jacobsen The shear deformation to load characteristics of bolts has long been established (Crawford & Kulak 1968) and used for the plastic design of bolted connections in shear. This relationship is directly transferable to the design of shear studs, typical properties are well known, and actual values easily established in simple lab tests. The author has taken this relationship and modified Amstutz theory (Amstutz, 1970) for shear anchored strengthened liner buckling, to give a more efficient solution, using readily available material properties."

Jan 1, 2019

By P. A. Manohar

This paper describes an implementation of the Potts model for simulation of grain growth in 2D on a distributed-memory parallel architecture. The simulation scheme utilizes a continuous-time, asynchronous parallel version of the n-fold way algorithm. Each Processing Element (PE) carries a piece of the global simulation domain while the virtual topology of the PEs is in the form of a square grid in 2D and Torus in 3D. Different PEs have different local simulated times. Inter-processor communication is carried by the Message Passing Interface (MPI) routines. Sample results for grain growth simulation in 2D are presented for a 840 x 840 global domain size distributed over 16 PEs. The grain growth kinetics obtained in the simulation of pure, isotropic systems is in good agreement with the theory. Grain size distributions obtained in the parallel simulation are well described by the lognormal distribution, thus validating the simulation procedure. Keywords: Metropolis algorithm. n-fold way algorithm, asynchronous parallelization, grain growth

Jan 1, 2003

By Emily Sarver

"Across all sectors and commodities, a common theme is driving progress in raw resource supply: sustainable development (SD). Over the past few decades, the mining and minerals industries for their part have undertaken significant and intentional changes at every level to become more responsible — no longer to just their shareholders, but also to the environment, to the communities in which they operate and to society at-large. Led by some of the global majors, these industries have indeed helped to define and operationalize the basic principles of sustainable development. Now in the midst of a full-on cultural shift, they are also key players in the continual effort to re-examine and calibrate practices to meet dynamic and increasingly complex objectives.SME’s technical position statementAs a home for so many technical experts and practitioners, SME has long recognized the importance of a commitment to sustainable development by the mining and minerals industries. In April 2016, the Society formally adopted a technical position on the topic following years of participation in, and support for, related activities. The full position statement appears below. It was drafted, revised and presented for approval to the board of directors by SME’s Sustainable Development Committee.Statement of Technical Position on The Mining Industry and Sustainable Development:• The National Environmental Policy Act of 1969 (NEPA) and the Surface Mining Control and Reclamation Act of 1977 (SMCRA) imposed considerable environmental restrictions on the mining industry; SME has always reinforced strict adherence to the laws.• In 2002, SME established a Sustainable Development Committee to lead its efforts in this area and to propel the organization into global prominence.• SME is a signatory to the Milos Statement of 2003 on Sustainable Development, so it is committed to providing scientific, technical, educational, and research skills in minerals, metals and fuels.• SME recognizes that SD programs adopted by the industry have a tangible return on investment through brand recognition and loyalty, facilitation of permitting, reduced occurrence of community protests and vandalism and diminished political risks.• SME actively promotes educational programs that encourage professional growth and interaction with the engineering professional community through books, articles, symposia, short courses and/or conferences on sustainable development in the mining and minerals industries.• SME has developed abundant expertise to provide balanced advice to government bodies, congressional staff and other interested organizations."

Jan 12, 2017

By A. Aubin, H. Yang, G. Zaluski

The Athabasca Basin of northern Saskatchewan and Alberta is an exceptionally rich metallogenic region, hosting more than 2.8 B lb U3O8, of which over 927 M lb U3O8 have been mined out since extraction first started in the late 1970’s. A detailed compilation of several empirical features of 85 deposits located within the basin was conducted in order to understand the distribution and variability of the geological characteristics of the mineralization and its associated alteration. A new empirical classification was devised based on four parameters: 1) geometry of the mineralization (dimensions and relation to the unconformity surface), 2) size, grade and metallurgical complexity of the mineralization, 3) lithostructural setting, and 4) extent and nature of associated alteration haloes. This compilation defines the footprint characteristics of the Athabasca Basin deposits, which guides decision-making processes from early exploration and discovery to resource expansion and extraction.

Jan 1, 2020

By L. A. Bellows

The "Athabasca oil sands" of the McMurray formation in northeastern Alberta cover an area of about 21,000 square miles and contain the world&apos;s largest reserve of oil. Fort McMurray, a small town in the heart of the oil sands area, is about 235 air miles north- east of Edmonton. A railway serves the town but no year-round roads connect the town with the rest of Alberta. (Figure 1). The McMurray formation is of early Cretaceous age, deposited unconformably on a limestone surface of Devonian age. The sediments appear to have originated from the Canadian Shield to the east and were deposited in bays and deltas of large fresh water lakes. The lakes were later replaced by marine seas in which t the overlying Clearwater shale was deposited. (Figure 2).

Jan 1, 1963

By Samer Sadek

The Georgia Department of Transportation (GDOT) undertook an exploratory feasibility study to one of the most ambitious tunneling projects in the United States. HNTB Corporation was retained to perform the study, deemed the Atlanta North-South Tunnel, which is approximately 7 miles long and consisting of four lanes (or six lanes) starting at the southern terminus of SR 400 extending to the south connecting with the northern terminus of I-675, providing substantial relief to the Downtown Connector (I-75/I-85), the most congested portion of Atlanta?s freeway system. This paper summarizes the analysis performed during the first phase of this challenging assignment which, if constructed, would be one of the longest roadway tunnels ever built in the United States.

By George E. Thackray

In December, 1894, the Cambria Iron Company made a number of heats of Bessemer steel to be used in structures by one of its customers, subject to inspection and tests by a firm of consulting engineers, one of the requirements being that the material should riot exceed .08 per cent. of phosphorus. In other respects the requirements were such that they could only be met by material of good quality; but the general spe cification is not introduced here, as it is not the purpose of this paper to deal with anything except certain difficulties encoun tered in determining the phosphorus-content of the material in a manner satisfactory to both seller and buyer. Preliminary determinations of phosphorus were made in sample-ingots from each of the heats from which material was rolled for the order in question, and these preliminary chemical tests, made in the laboratory of the Cambria Iron Company, showed that, with very few exceptions, every heat was within the prescribed limit of phosphorus. After the material had been rolled, sample-drilling8 of finished material were taken from the various heats in the regular manner in use at the works, these samples being thoroughly mixed and divided into two parts, one of which was analyzed at the works&apos; laboratory and the other sent to the inspecting engineer. Several hundred determinations were made from this mate rial without reaching an agreement between the work of the inspector&apos;s chemist and that of the works&apos; chemist; but as it is not the object of this memorandum to treat of this part of the subject at length, it is considered sufficient to present herewith only a few of these first determinations. The analyses given in Table I. are those of the original series made on the heats which were afterwards resampled for final determination by an arbitrator; and they are selected for this reason, as the entire " comparison is thus rendered more complete.

Jan 1, 1896

By William Glenn

In their account of chromium, Roscoe and Schorlemmer (Treatise on Chemistry, London, 1879) state that "In 1762 Lehmann, in a letter to Buffon, de nova minerœ plumbi specie crystalline rubra, described a new mineral from Siberia, now termed crocoisite." In 1786 Lehmann analyzed it (Nicholson&apos;s Jour., Dee., 1798) and found that it contained chiefly lead, and that the " mineralizers " were arsenic and sulphur. It was next examined in 1189 by Macquart and Vauquelin, who stated that it contained an intimate mixture of iron, alumina, and lead peroxide. The account of their work was published over the name of Macquart. Vauquelin (Louis-Nicolas) was a Norman peasant, who had studied in the village school, and at the age of fourteen was a laboratory-boy in a pharmacy at Rouen. Later, he found his way to Paris, and in 1789 was assistant to Fourcroy, a pharmacist and a teacher of note. It was here that he met Macquart, with whom he did the work on Siberian red lead, and at this time his friend Cheradame taught him his Latin.

Jan 1, 1896

E. C. Pechin, Buchanan, Va.: I am sorry to see the table appended to Mr. Chase&apos;s excellent paper. In the discussion at the same meeting, on "Notes on a Southern Coal-Washing Plant," Prof. Phillips very properly says: " There is no use in giving an analysis as representing a coal when it does not do so. It gives a wrong impression of the conditions under which business is conducted." The same may be said about ores. I have no personal knowledge of the ores in many of the localities given in Mr. Chase&apos;s table; but if these are to be judged by what is positively known of the Cranberry ores, the analyses are grossly misleading. The furnace-shipments from Cranberry have rarely reached 44 per cent. of iron, and any such percentage as 58 or 66 or 68 can only have come from hand-picked specimens. Indeed, with any such percentages, Mr. Chase&apos;s paper would have been superfluous, because concentration would be unnecessary. Besides, the paper itself (page 553) gives the fact that the Cranberry average is 42 to 43 per cent. Why should a table be appended, contradicting this statement of the text ? Let us always have the exact conditions under which business may be conducted. "Boom" and business analyses are widely different.

Jan 1, 1896

Albert Arents, Alameda, Cal.: From Mr. Furman&apos;s description of his crucible-assays I infer that he regards iron nails as a necessary or advisable adjunct. Against such a notion I must beg leave to protest. Nails should not be used in

Jan 1, 1896

William Clinton Brown, Brooklyn, N. Y.: The demand for an apparatus for cooling water for condensers, refrigeratingmachinery and air-compressors, as well as water-jacketed furnaces, has led manufacturers to put such an apparatus on the market, so that it is now possible to purchase a cooling-tower, properly designed and constructed, by simply stating the amount of water to be cooled and the temperatures of the hot and the cold water. The principle is similar to that described by Mr. Henrich, but wood is not used in the best apparatus. There are two great objections to wood: First, it cannot last long under the very trying conditions to which it is subjected; and second, it absorbs the organic matter with which water in constant use becomes impregnated, and the resulting odor is very disagreeable. A few days ago I saw a cooling-tower and condenser, built by the Henry R. Worthington Co., in operation at the Edison electric-lighting station in Brooklyn, N. Y., cooling the water for a 700 horse-power condenser. It consisted of a large stack of iron, about 15 feet in diameter by about 30 feet high. This stack was filled with tiling through which the water falls. A whirligig distributes the water evenly over the top, and a large fan, about 6 feet in diameter, driven by a 10 horse-power electric motor, blows air into the bottom, thus giving a positive circulation. The water, in running down the sides of the tiling, is met by the blast of air, and enough is evaporated to cool the rest. The vacuum-gauge on the condenser showed 26 inches; so the condenser was undoubtedly getting sufficient cool water.

Jan 1, 1896

Jan 1, 1896