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By S. N. Lekakh

Phosphorous segregated at grain boundaries during solidification and heat treatment dramatically decreases low temperature toughness of precipitation hardened Fe-Mn-Al-C austenitic steel. A thermodynamic analysis was performed to evaluate the possibility of decreasing P and subsequent segregation by Ca- and Ce-additives in the melt. It was shown that the predicted probability of forming a P containing compounds depends on melt composition and treatment sequence. Experimental heats were performed and several micro- and macro-structural effects of Ca- and Ce-additives were recognized by using an automated inclusion analysis technique.

Jan 1, 2010

In dealing with the pulverization and treatment of auriferous ores, it may be stated that there is not one system of treatment applicable to all classes. In the southern portion of New Zealand the ores generally contain free gold, with scarcely any impurity that is, it is found in an almost pure state, without any alloy, and its dissemination amongst the matrix is generally in tolerably coarse particles. The only difficulties the mill man has to contend with, are the economical concentration of pyrites, which in some of the lodes are rich in gold, and the extraction of the gold the pyrites contain. In some of the lodes there is what may be termed float gold, that is, the particles of the precious metal are so finely divided that it passes over the quicksilver tables, and, unless there are other appliances for saving it, this class of gold is entirely lost.Indeed it is only within the last five years that any attention has been given, in the southern portion of the colony, to saving the fine gold that has passed the amalgamating tables. In the North Island the ores are very complex there are scarcely two mines, although they may be adjoining each other, where the bullion is of the same character. On every field the gold is alloyed with silver', and in combination with other metals and mineral substances, such as copper, zinc, antimony, galenfl, iron, sulphur, arsenic, etc., and, in some instaaces, cinnabar, as in the case of the Champion lode at Tui Creek, Te Aroha. Ores of this class are extremly difficult to treat satisfactorily.

Jan 1, 1903

By McIntosh A. H, Torlach J. A

Since the last paper on mining methods was presented to the Annual Conference of the Australasian Institute of Mining and Metallurgy in 1:960, numerous advances have been made in drilling and blasting techniques at Mount Morgan. This paper describes the drilling and blasting methods being employed in the open cut. The change over to track mounted percussion drills for all types of primary drilling is almost complete and new techniques such as detergent drilling and pressure loading of ANFO are being applied successfully.

Jan 1, 1965

By W. Barthel, B. A. Dippenaar, J. Malan

In its most basic form, the process of sintering is very simple, and has been in use since the turn of the previous century. However, while the basic process is simple, control of the process relies on a number of extremely complex interdependent process parameters and requires a thorough understanding of the effect of these parameters on production capacity and product quality. Further, as with many other processes, the process parameters and hence design details of visually similar installations are highly dependant on the specific feed materials. While the industry trend has been towards an increase of capacity in order to lower unit production cost, typically in Iron ore sintering plants, this approach is not always possible for other commodities because of the scale of operation. This paper seeks firstly to describe some design considerations of sinter plants; secondly, to report on results from testwork performed with a specific series Manganese ore blends; and last, to relate these results to the design of new small-scale Manganese ore sinter plants.

Jan 1, 2004

By M. Abzalov

"Control of analytical data quality is usually referred to in the mining industry as Quality Assurance and Quality Control (QAQC), and involves the monitoring of sample quality and quantification of analytical accuracy and precision. QAQC procedures normally involve using sample duplicates and specially prepared standards whose grade is known. Numerous case studies indicate that reliable control of sample precision is achieved by using approximately 5% to 10% of field duplicates and 3% to 5% of pulp duplicates. These duplicate samples should be prepared and analyzed in the primary laboratory.Bias in the analytical results can be identified by inclusion of 3% to 5% of the standard in each sample batch. Several different standards are used, with values spanning the practical range of grades in the actual samples. A blank (a sample in which the concentration of metal of interest is below detection limit) should also be included. Standard samples alone cannot identify biases introduced during sample preparation, and therefore approximately 5% of the duplicate samples (coarse rejects and pulp) should be processed and assayed at another, external, reputable laboratory.This paper discusses techniques used for estimation of errors in precision and accuracy, and overviews diagnostic tools. It is shown that one of the most commonly used methods, the Thompson-Howarth technique, produces consistently lower results than other methods. These results reflect the nature of this method, which relies on the assumption of a normally distributed error, and thus produces biased results when errors have a skewed distribution. This study concurs with the suggestion of Stanley and Lawie (2007: Exploration and Mining Geology, v. 16, p. 265-274) to use the average coefficient of variation (CVAVR(%)) as the universal measure of relative precision error in mine geology applications: Le contrôle de la qualité des données analytiques est habituellement désigné sous l’appellation d’Assurance et Contrôle de la Qualité (ACQ), elle implique le suivi de la qualité des échan¬tillons et la quantification de la reproductibilité et la précision analytiques. Les procédures des pro¬grammes d’ACQ impliquent habituellement l’usage de duplicata et de standards analytiques dont la teneur est connue. Plusieurs études de cas indiquent qu’une bonne fiabilité du contrôle de la précision des échantillons est atteinte par l’usage de 5% à 10% de doublons sur le terrain et de 3% à 5% de doublons de pulpe. Ces duplicata devraient être préparés et analysés au laboratoire principal.Un biais des résultats analytiques peut être identifié par l’inclusion de 3% à 5% d’échantillons standard dans chaque envoi d’échantillons. Plusieurs standards sont utilisés, avec des valeurs couvrant l’étendue des teneurs habituellement rencontrées dans des échantillons réels. Un blanc (un échantillon dans lequel la concentration d’un métal donné est sous la limite de détection) devrait aussi être inclus. L’emploi exclusif d’échantillons standards ne permet pas l’identification de biais résultant de la préparation des échantillons, de telle sorte qu’environ 5% des duplicata (rejets grossiers et pulpes) devrait être traités a un autre laboratoire indépendant et fiable.Cet article passe en revue les techniques utilisées pour évaluer l’erreur liée à la précision et a la reproductibilité, et effectue aussi un survol de divers outils diagnostiques. Il ressort de cet examen qu’une des techniques les plus fréquemment utilisées, la méthode Thompson-Howarth, fournit des estimés systémati¬quement inférieurs à ceux provenant des autres méthodes. Ces résultats sont un reflet de la nature de cette méthode, laquelle assume une distribution normale de l’erreur, biaisant ainsi les résultats lorsque l’erreur présente une distribution asymétrique. La présente étude recommande de privilégier l’usage du coefficient moyen de variation (CVAVR(%)) en tant que mesure universelle de la précision relative de l’erreu"

Jan 1, 2008

By Christoph Mueller

Mining operations today are characterized by a high degree of mechanization and single machine automation. However, their potential for cost cuttings and increase of productivity in the future is quite limited. Enabled by newest IT and networking technology, the operation of underground mines more and more can be seen from a process related point of view: Standardized Ethernet and Wireless LAN are the basis for a seamless and unified communication backbones providing an integrated infrastructure for data, telephony and video. All the components are available as off-the-shelf devices leading to an excellent cost efficiency. Basing on this standardized infrastructure, the equipment is able to become part of the infrastructure. To enable machines to be integrated smoothly into IT networks, the machine also has to have enhanced networking capabilities. This results in a new system architecture for the on board machine electronics separating real time control from IT and networking level functionality which can be implemented by a Machine Server. This machine server communicates with all kinds of above ground systems using mainly standardized formats like html or the IREDES standard. This information is made available mainly in 3D mine visualization tools. The paper explains this technology and shows implementations by two working examples.

May 1, 2006

THE following brief paper is submitted with a view to encouraging the exploitation of hitherto neglected 10w~ grade ore-bodies which are suitable for extraction by open-cut methods.The Corinthian North mine, situated 10 miles from Southern Cross, in the Yilgarn district of Western Australia, furnishes an example of low working costs, although operations are carried out on quite a limited scale.The body of quartz which is now being worked strikes N.W. and S.E., has a very slight underlie to the west, and lies between bodies of quartz-hrematite s,chist on the east and amphibolite on the west.So far as the property has been explored, it would appear that the underlying sulphide rises to within about 70 ft. of the surface in the northern end of the workings, and pitches away to the south at a grade...

Jan 1, 1915

By George S. Dulikravich

An advanced semi-stochastic algorithm for constrained multi-objective optimization has been adapted and combined with experimental testing and verification to determine optimum concentrations of aJ10ying elements in heat-resistant and corrosion-resistant H-Series austenitic stainless steel alloys. The objective was to simultaneously maximize a number of alloy's mechanical properties. This research will result in a rigorous tool for the design of high-strength H-Series steels and other types of alloys unattainable by any means existing at the present time. Such a material-by-design tool will also be able to reduce or minimize the need for the addition of expensive elements such as Cr, Ni, Co, Nb, Ti, V, etc. and still obtain the optimum properties of an aJ1oy.

Jan 1, 2003

By Merete Tangstad, Kai Tang

The primary aim of the present investigation is to develop a model which permits to calculate/predict the viscosities of ferromanganese slags, typically focus on the MnO-SiO2-Al2O3-CaO-MgO-FeO multicomponent system. The present viscosity model emphasizes the ability of prediction, i.e. using the binary parameters to extrapolate the viscosities in ternary and higher order systems. To this end, a physical sound model is essential. Temperature dependence of viscosity is described by the Eyring?s formalism. The well-known cell model is used to define the SiO44- tetrahedra in the silicate melts. Composition dependence is expressed in term of viscous activation energy, which is characterized by the binary structural units. The viscosities in ternary and higher order systems are hence predicted using the binary activation parameters. The model has been used to calculate the viscosities in the whole liquid composition range of ferromanganese slag.

Jan 1, 2007

Discussion of the paper of Robert Henry Lee, presented at the New York Meeting, October, 1913, and printed in Bulletin No. 82, October, 1913, pp. 2515 to 2522. J. E. JOHNSON, JR., New York, N. Y.:-This subject is of great and increasing importance, as the exhaustion of the deposits of ore of ideal character compels the iron industry to turn more and more to those which are less desirable on account of physical structure as well as analysis. Thus there has come about the use of the Mesabi ores in this country and also of the Minette ores in Europe, which produce far greater percentages of flue dust than did the lumpy ores first used. It is a matter of common knowledge that the utilization of this flue dust, containing commonly 50 per. cent. or more of metallic iron, has been a problem very difficult and tedious of solution. The number and variety of the solutions now offered is a sufficient proof of this. . I have no intention of going into the merits or demerits of any of these processes as such, but there are certain considerations concerning the effect of their product on the operation and fuel economy of the blast furnace which I believe to be new and which I desire to bring out. There are two methods, so different as almost to be direct opposites of each other, whereby an ore may exercise an unfavorable effect on the economy of the blast furnace. The first of these is well known and results from the ore being refractory and highly resistant to the action of the reducing gases of the blast furnace. This results in its being incompletely reduced when it reaches the zone of fusion and in the reduction being finished by the direct action of carbon in the lower portion of the furnace. This is so well understood as to need little elaboration or comment. There is, however, another action which may be equally as fatal to the economy of the furnace as the foregoing, and as this point is, to the best of my knowledge, not generally appreciated, it is one upon which I desire to lay particular stress. This consists in the ore being, in a sense, too reducible.

Jan 12, 1913

By T. C. Wesson

The need for elemental-analysis information on coal mine dust for use in health and safety research prompted this study by the Bureau of Mines. Neutron-activation and X-ray fluorescent techniques were used to obtain five-element analysis (silicon, aluminum, iron, calcium, and magnesium) on 444 samples from 68 coal mines in 10 States. From these analyses, the average composition of the dust in coal mines was determined. The contribution of the primary dusting material (limestone dust) to the makeup of coal mines was shown. Regional differences in mine-dust composition were indicated.

Jan 1, 1974

By Paul F. Gnirk, Ralph A. Wagner, Joe L. Ratigan

This thermomechanical analysis used the finite element method to investigate the behavior of crushed salt backfill in a waste disposal room situated in a salt dome repository. The first of two objectives was to determine the transient temperature rise and degree of thermomechanical consolidation that occur in the backfill as a function of drillhole depths. The second objective involved the evaluation of closure due to salt creep of unlined emplacement drillholes and the determination of pressure on steel sleeve liners in the drillholes should liners become necessary for canister retrieval. The retrievability period was considered to extend for 25 years after waste emplacement. The canisters were assumed to contain ten-year old high level waste with a thermal output of 4.3 kW at the time of emplacement.

Jan 1, 1981

By Joshua A. Bennett

"Lawsuits where owners allege their property has been damaged by nearby blasting routinely costblasting companies, explosives engineers, and others in the field both time and money. When ownersfeel the vibration of a blast, they immediately begin to look for damage and usually find cracking thatwas, in fact, present prior to the blasting occurring. When those owners begin to talk to their neighbors and legal counsel, blasting entities suddenly have multiple lawsuits being filed as a result of the same blast."

Jan 1, 2016

By Sam Kangwa, Thomson Sinkala

Th e re are three basic types of hole deviations in long hole d ri l l i n g , n a m e l y collar i n g , alignment and tr a j e c t o r y dev i a t i o n s . In mining, the accur a cy in drilling has a significant effect on the effi c a c y and economy of mining oper a t i o n s . This ar t i cl e d e s c ribes the types, s o u r ces and effects of hole deviations in mining oper a t i o n s . The art i cle further demonstrates the economic consequences due to hole dev i a t i o n s .

Jan 1, 2004

By E Kasai, T Nakamura, E Shibata

In the present study, formation of PCDD/Fs from carbon particles like æsootÆ, so called de novo synthesis, was experimentally simulated using the powder mixture of graphite and metallic chloride. Composite states of graphite and chloride particles were varied by the preliminary treatment, ie high-energy ball milling for different time or heating at different temperatures. These samples were subjected to the measurement of the rates of weight loss mainly due to the oxidation of carbon, the formation of absorbent organic chlorides (AOX) and the formation of PCDD/Fs at 300¦C. The amount of PCDD/Fs formation increased by applying certain pretreatments. Further, linear relationships were obtained among the formation rates of PCDD/Fs and AOX and the weight loss of sample. These results will give useful information to investigate the mechanism of PCDD/Fs formation from unburned combustible carbon and hydrocarbon in thermal processes.

Jan 1, 2002

By Qinghua Tian, Zhipeng Xu, Dong Li, Xueyi Guo, Liu Zhu

A possible process for extracting tellurium and antimony from a residue generated in alkaline sulfide leaching of telluriumbearing alkaline skimming slag was proposed. The central composite design was employed to define the optimal leaching conditions for tellurium and antimony extractions from the residue sample. Using a 23 factorial matrix, the best performance for tellurium and antimony extractions (96.36% and 99.64%) were obtained at 175 g L−1 Na2S concentration for 80 °C during 60 min. The notable degree for influencing tellurium and antimony extractions was leaching temperature, Na2S concentration, and leaching time. The analysis of variance results indicated that the regression model was significant and suitable to be used for the optimization of independent variables within the range. The model was validated under optimal operating conditions based on the experimental design results. Antimony and tellurium in the leach liquor were separated and recovered by H2O2 oxidation followed by Na2S-Na2SO3 reduction. 98.93% of antimony was precipitated selectively during H2O2 oxidation, while 95.06% of tellurium was precipitated during Na2S-Na2SO3 reduction. NaSb(OH)6 and elemental tellurium was obtained as the product.

By William J. Purdy

Successful design, operation and completion of a surface waste management facility for a diamond mine located in Canada?s northern environment requires careful planning to minimize short and long term environmental impacts. As part of the mine development application process, best practice standards were applied using conventional engineering to reduce the environmental effects of the mine waste facility at the Snap Lake Diamond Project. This paper presents the design criteria, site conditions, material characteristics and engineering management objectives considered for optimization of the development plan. Insight into the engineering analyses, development alternatives, monitoring program and reclamation strategy plan to be undertaken during mine operations to provide opportunity for adaptive management and to minimize environmental impacts is provided.

May 1, 2004

By Tom Treleaven, Andrew Williams

The town of Greenwich, CT, an exclusive suburb of New York City awarded several contracts for the installation of sanitary sewer in the North Mianus section of town. The Valley Road section was the most challenging from a rock excavation standpoint. The cut was up to 14 ft (4.25m), with adjacent utilities [20 in. (500mm) water, 6 in. (150mm) water and 8 in. (200mm) gas] located to within 5 ft. (1.5m) of the proposed sewer trench. Rock types varied but were ultra metamorphic in nature, ranging from quartzites, granite gneiss and various types of migmatities.

Jan 1, 2004

By Lee T. J

The area, A, under a gamma-ray log that passes through a horizontal bed given by: A = gl/k. Here is the equivalent concentration of U3O8 in the body, l the thickness of the body, and k the calibration factor or sensitivityof the logger. The area is independent of the logging speed or logger time constant.This relationship, together with the first moment about the maximum of the log and its value there suflicient to determine the thickness, position of the centre of the bed from the log maximum and the concentration of U3O8.Numerical results obtained from artificial and field data show that the computed results arc as good as those obtained by methods such as the inverse filter technique and the iterative method. The present method yields results that arc easier to feed into an ore reserve data base.

Jan 1, 1981

Drill cores from Section 62, New Broken Hill Consolidated Ltd., were used to study the petrology of rocks associated with the zinc lode. The distribution of the rock types in relation to the lode structure was determined. The distribution of the gahnite-bearing rocks was shown to be only partly conformable with the structure.It was concluded that large scale metasomatism was not widespread, that the rocks associated with the lode (except, perhaps, the quartz-gahnite-garnet rocks) were formed by metamorphism of sediments, and that rocks and lode were contemporaneously metamorphosed.INTRODUCTIONThis investigation was undertaken in order to study the rock types associated with the zinc lode of the Broken Hill orebody, and their relationship to the structure of the ore horizons. The work was confined almost entirely to the laboratory, and is therefore limited in its scope. It is hoped, however, that the information gained may throw some new light on the genesis of the lode.Certain inferences which are drawn from this work are at variance with the ideas of a number of earlier workers.In particular, the idea of large scale metasomatism developing many of the rocks associated with the lode, especially those containing manganese, is questioned. On the contrary, the rocks associated with the lode are more simply explained as highly metamorphosed sediments, in some cases modified by water introduced from surrounding rocks into zones of strong folding and faulting. As a corollary, a metamorphicsedimentary origin for the lode material, either as a concentrated sulphide deposit, or somewhat disseminated...

Jan 1, 1961