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By Potter G. M.

Ore-dressing tests were conducted on a sample of ore submitted by the Richmond Hill Mining Co. of Lead, S. Dak. as a part of the Bureau of Mines program for investigating potential domestic sources of manganese. Half of the sample was taken from the 300-foot level and half from surface cuts. The problems involved were liberation and rejection of silica and iron and removal of lead, Silver, and gold from the manganese concentrates. Although a portion of the silica and iron oxides was too intimately associated with manganese minerals for rejection by ore-dressing methods, thus limiting recovery of high-grade concentrates, the Richmond Hill ore was found amenable to simple gravity methods of concentration for producing intermediate-grade products. By jigging and tabling, 73.8 percent of the total manganese was recovered in a product that, when sintered, assayed plus 40 percent Mn. Lead, silver, and gold were successfully removed from gravity concentrates by a chloridizing roasting treatment.

Jan 1, 1948

By V. Rajaram

The Metropolitan Water Reclamation District of Greater Chicago (MWRD) imposed a no-blasting specification (blasting is restricted to the construction shaft and shaft bottom or boot) on the Deep Tunnel project in 1988. This was prompted by numerous complaints from the residents in the vicinity of the project, and controversies experienced on previous projects from blasting the rock overlying the tunnel. This paper will describe the methods utilized by two major contractors who are driving 20 km (12.5 of tunnel along with drilling over 36 shafts under this restrictive specification. The impacts on design, construction, schedule, cost, and the environment are detailed.

Jan 1, 1991

The ore milled from the Lead Lode of The Zinc Corporation leases consists of a fairly granular mixture of galena, marmatite, chalcopyrite, tetrahedrite, pyrrhotite, pyrite, and lollingite with a gangue association of calcite, quartz, bustamite, rhodonite, mangan-hedenbergite, garnet, fluorite, mangal1o-calcite and apatite. The silver content of the ore occurs in three minerals-tetrahedrite, dyscrasite, and pyrargyrite, the last two mentioned occurring in microscopic association only. Other metallic and gangue minerals are also present in this complex mineralogical association, but do not influence the milling operations. Fortunately, the silver minerals favour the galena and chalcopyrite as their host minerals, thus facilitating the recovery of both copper and silver in the lead concentrate. The ore from the Lead Lode assays from 14-18% lead; 3·0-4·5 oz. silver per ton, and 9·5-12·0% zinc.A parallel lode, known as the Zinc Lode, is well developed in The Zinc Corporation leases. This lode assays from 6-8% lead, 1·5 oz. silver per ton, 18-25% zinc with a siliceous gangue. The common Lead Lode gangue minerals-ealcite, rhodonite, bustamite-are very rare in present underground exposures. No metallurgical work was done on this ore during the pilot plant operations.The aim in the milling process is to produce: 1. A lead concentrate with the maximum economic recovery of lead, silver, gold, copper and antimony, and minimum zinc content.2. A zinc conc,entrate with the maximum economic recovery of zinc, cadmium, and cobalt, and minimum iron, arsenic and fluorine content.3. A waste residue containing sufficient granular material to be utilized as underground fill.In considering the economics of the milling practice the above three requirements plus consideration of the tariffs submitted by the purchasers of concentrates were the deciding factors in the evolution of the present milling practice.Towards the end of 1924 The Zinc Corporation Limited added to and adapted the old zinc tailings plant for the treatment of 5,000 tons of crude ore per week. This plant, which operated until January, 1936, was in general principles similar to the standard Broken Hill methods of ore concentration, whereby the galena was recovered by the gravity concentration methods of Hgging and tabling with selective flotation concentration of the residual galena and marmatite. One important difference from other Broken Hill plants was that the primary grinding of the jig tailing was performed with flint-loaded mills operating in closed circuit with revolving screens. Two primary grinding sections were installed, each...

Jan 1, 1941

By Ta M. Li

How do you convert a copper-zinc resource into a viable economic mining operation? This problem, unlike most, was complicated by the additional presence of a sub-arctic climate, highest labor costs in the world, low-grade copper-zinc values, depressed market prices, and a complex mineralization.

Jan 12, 1977

By J. J. Carlson

Studies were carried out to determine whether filtration rate changes observed in an iron ore concentrator were due to variations in particle shape. It was confirmed that ores mined from different locations differed in filtration rates by as much as 60%. However, when image analysis was used to quantify the shapes of the individual particles in the filtration feed, it was found that the particle shapes showed almost no variation, and the shapes did not correlate with the filtration rate. It was also determined that the filtration rate variations were not caused by changes in particle size distribution. These results suggest that the differences in filtration rate are due to factors other than size and shape, such as surface chemistry.

Jan 1, 2008

By P Krauss, S Harpalani

Methane emitted from underground coal mines, along with ventilation air and known as ventilation air methane (VAM), constitutes the largest component of coal mine methane (CMM) emissions. Atmospheric methane, on the other hand, is a potent greenhouse gas with a significant adverse impact on the atmosphere. This has led to the development of various technological alternatives for its use as an energy fuel. Techniques involving oxidation of VAM, usually consisting of very low concentrations of methane, have been validated in the past. Prominent among these technologies are the thermal and catalytic flow reversal reactors, ancillary fuel technologies, lean fuel gas turbines, and concentrators and gasifiers. However, the efficiency of any VAM utilisation technique depends on the amount and concentration of methane in the ventilation exhaust air. Therefore, quantification of VAM emission from a coal mine is the first step towards identifying the most suitable technology for its utilisation for energy production. This paper presents an evaluation of the efficacy of VAM as an energy source. It provides details of a case study aimed at developing a technique to accurately quantify VAM emission from a coal mine. It further discusses the various VAM utilisation techniques available, and presents an economic evaluation of the alternatives. Based on the findings of the study, the most feasible method for VAM utilisation is identified for the mine. The paper summarises the procedure for quantifying VAM emissions and selecting the most suitable utilisation technique.

Jan 1, 2005

By M A. Wells

A new approach to more reliably predict the Ni (and Fe, Mg) composition of Ni laterites was tested for RC samples from the (siliceous) oxide–style, Siberia North deposit, Kalgoorlie Nickel Project (KNP), in the north-eastern Yilgarn (WA) using partial least squares regression (PLSR) analysis of diffuse reflectance spectra over the 380 - 2500 nm wavelength range with a multi–element chemistry data set. PLSR cross-validation models were developed to predict FeO, MgO and Ni contents in composite samples with bulk composition limits of >0.08 wt per cent Ni and <6 wt per cent MgO. Calibration and validation models showed a strong, linear trend for predicting FeO and, to a lesser extent, Ni content, whereas PLSR models for predicting Mg content were less reliable. This reflected the prevailing mineralogy and associated element deportment within the oxide laterite profile. For example, Fe and Ni distribution is controlled by relatively few minerals, predominantly goethite and, to a lesser extent, the Fe3+-bearing smectite, nontronite. Magnesium is associated with a range of Mg-bearing minerals, some of which are compositionally complex (eg serpentine, talc, chlorite, smectite and carbonates). Magnesium chemistry alone does not reflect the varied mineralogy of samples with relatively high (5 - 6 wt per cent) MgO contents, which can be spectrally distinct. Hence, samples with similar Mg contents, though comprising Mg-bearing minerals with distinct reflectance spectra, were difficult to model (eg smectite versus Mg-carbonates). The findings of this study demonstrate that characterisation of Ni laterite composition may be achieved as part of routine logging of either drill chips or diamond drill core using PLSR analysis, but that a detailed understanding of the mineral-element association is essential for reliable predictive analysis. This has particular relevance to characterising the geometallurgy of Ni laterites, especially where deposits may be classed as the same type, but have distinct compositional and mineralogical differences.

Sep 5, 2011

A series of physical tests have been conducted to determine the actual performance of bunton to shaft side wall connections typically used in new shaft construction in South Africa. The test set-up is described, together with the applied loading, which incorporates a cyclical load component and a quasi-static load component, in an attempt to simulate actual conditions in the shaft. The test results are given and it is shown that generally the performance is adequate, provided double-slotted holes are not used. Generally the fatigue performance is found to be good, with the only exception being cases where the bottom of the bunton is lower than the seating level for the bunton to side wall connection. Arising from the tests, typical design values of connection stiffness, strength and fatigue life are proposed and a design procedure including these three key aspects of connections is described.

Jan 1, 2005

By F. Calizaya

This study summarizes the ventilation requirements for the highly mechanized PT. Freeport Indonesia's underground mine operation in Irian Jaya, Indonesia. The deep ore zone (DOZ) is a coppergold deposit that is being developed underneath the current intermediate ore zone (IOZ) mine. One of the company's current plans is to prepare this mine for a steady ore flow of 25 kt/d (27,500 stpd) by 2003. This study includes the estimation of airflow requirements for various mining activities, the design of major intakes and returns, the determination of airway resistances and specifications of fan duties. It also includes the results of air pressure/quantity measurements in existing airways and the standards stated by the current Indonesian mining law.

Jan 1, 2000

By N. P. Widodo

The ventilation measurements by tracer gas method at Pongkor gold mine show that effective diffusion coefficient, E, at straight airways indicated a similar range of measured one by the laboratory experiments which can be estimated by Taylor equation. On the other hand, E of the curved airways in the mine was estimated as larger than that of the straight ones (1.5 to 32 times than that obtained by the Taylor equation and these have been compared with the data measured in Kushiro coal mine, Japan). The curved mine airways, with small curvature against airway radius and complex velocity profile, possibly give concentration ? time curves with long tailings, thus those airway conditions could make larger E. Laboratory experiments of gas diffusion by a pulsed injection of small amount gas, into straight and curved airways, have been conducted in order to investigate a range of E in mine airways. The plots of E against Reynolds number show that the present laboratory results of straight-long airways are almost close to one calculated by Taylor equation. On the other hand, the values of E measured at curved single-direction airways were smaller than that of the straight airways, which may be due to effects by secondary vortexes flow in the curved airways.

Jan 1, 2009

By R. M. Reyes, D. Negrete, G. Herrera

First Majestic Silver Corp’s La Encantada Silver Mine is a producing mine with a capacity of 3,000 tonnes per day. The La Encantada team is currently constructing two small-scale caving mines, including the San Javier breccia caving mine. The new mine is constructed within a mineralized breccia body composed of clasts of varying sizes and with very poor rock quality. Due to this poor rock quality, primary and secondary supports are required to support both the development and production stages. Since the proximity of the new mining levels to existing old workings, correct selection of the support system and proper production controls, instrumentation, and monitoring are very critical to maintain the stability of the pillars and fortification elements. An increased ground deformation due to the load transfer during the production stage is expected. This report reviews the primary and secondary support elements used in the different stages of mining, the monitoring of ground deformation, and the steps taken to analyze and visualize the collected data in order to enable the geotechnical team to manage caving stress and maintain pillar stability. INTRODUCTION First Majestic Silver Corp. (“First Majestic”) is a Canadian mining company focused on silver production in Mexico that operates six producing silver mines, including La Encantada Silver Mine (“La Encantada”). First Majestic acquired La Encantada in 2006. La Encantada is located in the northwestern portion of the state of Coahuila, in northern Mexico, in the municipality of Villa de Ocampo. The mine lies in the northern part of the Sierra Madre Oriental physiographic province. The mine location is shown in Figure 1. La Encantada is a producing mine, with a mill processing capacity of 3,000 tpd, and a 4,000 tpd capacity cyanidation leaching circuit equipped to process fresh underground ore and old tailings amenable to be reprocessed. The mine is currently employing several mining methods, including overhand cut and fill for narrow veins, small mantos, and other minor deposits. A subset of caving methods are applied on the larger, but weak, mineral deposits, such as at the San Javier breccia and La Prieta breccia. La Encantada consists of vein, manto, breccia pipe, and chimney deposits with concentrations of silver, lead, iron, and zinc in oxidized mineralization enclosed by calcareous sedimentary formations of Cretaceous age. At deeper levels, there is sulphide mineralization in skarn with zinc and silver concentrations associated with a granodiorite intrusion.

Jan 1, 2019

By A L. Wills

Cliffs Natural Resources Pty Ltd (Cliffs) operates iron ore mines in the Koolyanobbing region of Western Australia. Ore is mined from three separate hubs and trucked to Koolyanobbing. There it is crushed and screened to lump and fines finished products and railed to Esperance port for export to Asian customers. Cliffs is renowned in the marketplace for its consistent product quality. In 2010, 9 Mt of ore was exported to Asia.Over the last three years, Cliffs has systematically refurbished its product quality system (PQS), to improve efficiency of production while maintaining its high standard of product quality. Particular attention has been given to reducing inventory, which has required significant modifications to the production process design.In redesigning the production process, emphasis was placed on maximising the application of the inherent blending in each of the production process steps and dedicated blending was only introduced where essential. Simulation modelling and statistical analysis of process capabilities were utilised to develop a system that optimises inventory, minimises rehandle, eliminates several decision-making steps and maintains a pull focus throughout the value chain.The new planning functions are now fully integrated and effectively control long-term grade variability rather than relying on long-term stockpiling. The production process design and the daily crusher blend plan are used to control short-term grade variability. With the upgrading of the planning processes the accuracy and consistency of algorithms for lump per cent and lump and fi nes grades became more important and an increased geometallurgical function has been added to the company.The continuous stockpile management system was upgraded to increase the effectiveness of the daily crusher blend planning process and is now the sole intervention point in the production process for grade-based decisions. Grade control systems were modified to utilise advances in software and geostatistics to deliver accurate short range planning models. The reconciliation and sampling systems have also been refurbished with an emphasis on practical application and feedback loops.Accountability and transparency are provided by management reports that are generated from a centralised data warehouse and the introduction of a corrective action system. Standardised reports are available to all stakeholders and a quarterly KPI scorecard assists the management review process.The successful rejuvenation of the PQS has culminated in operational efficiency through the implementation of an integrated end-to-end process flow. Shareholder value is maximised through maximising recovery of the resource and minimising costs. Customer focus is maintained by reliably delivering product with acceptable and low grade variability.

Jul 11, 2011

By M. Kaufman, A. E. Palty

The phase structure and aging characteristics of two nickel-base alloys, Inconel 718 and 702, were investigated. Wrought and cast Inconel 718 showed ArisCb as the major hardening phase, as well as ture was positively identified. Inconel 702 had Ni3Al as the major hardening phase, as well as Cr7C3-of the phase amounts with temperature was determined. 1 HE value of phase structure and aging rate information in the utilization of alloys has been well established. As part of a continuing program, the results obtained on two nickel-base alloys, hconel 718 and Inconel 702, are presented here. Inconel 718 is a relatively new alloy considered for application in both sheet and cast form. Its novelty lies in the use of high columbium tantalum levels in a Ni-Cr-Fe base. No previous work on this type of alloy has been reported in the literature. Inconel 702 is being used now as an oxidation-resistant sheet alloy. Occasional fabrication problems spurred work on its basic structural behavior. The composition of 702 is essentially nichrome plus aluminum and titanium for strengthening and added oxidation resistance. This puts it in the basic class of other nickel-base alloys which have already been studied. The two alloys will be treated separately. INCONEL 718 Phase Study Methods. The phases present after the various conditions investigated were determined by X-ray diffraction analysis of two different elec-trolytically extracted residues and microscopic examination. The extraction methods, using 10 pct HC1 in alcohol and 10 pct H3PO, in water and the X-ray technique have been described previously.' The effect of temperature on the phase behavior was studied on sheet material using the following heat treatments: 2250°F, 2 hr, ice brine quench 1300 100 hr, water quench 2250°F, 2 hr, ice brine quench 1400°, 100 hr, water quench 2250°F, 2 hr, ice brine quench 1500°F, 100 hr, water quench 2250o 2 hr, ice brine quench 1700°F, 48 hr, water quench 2250°F, 2 hr, ice brine quench 1850°, 24 hr, water quench 2250°, 2 hr, ice brine quench 2000°F, 6 hr, water quench The high solution temperature was an attempt to dissolve as many phases as possible without causing melting. Aging exposures were made longer than normal heat treating times in order to approach equilibrium conditions more closely. Cast material was examined only in the as-cast condition and with the normal heat treatment (1700°F, 1 hr, air cool 1325oF, 16 hr,air cool). Materials. The full phase study was performed on sheet specimens approximately 1/2 in. by 2 in. by 1/16 in. The cast pieces were cut from the gating system of a vacuum-cast test piece. An all weld-metal specimen was made by running many weld beads on the sheet using filler made from the sheared edges of the sheet. All external contamination was removed by belt-sanding followed by an electro-polishing treatment. The typical composition of wrought Inco 718 is as follows: The alloy is air-melted. Cast hco 718 may have higher molybdenum. Due to the expectation of finding a Ni-Cb phase (Ni, Cb) for which no X-ray diffraction pattern was available in the ASTM Index, a special 5 Ib heat to the stoichiometric composition of this intermetallic

Jan 1, 1962

Separates of all the Technical Publications published in 1930 are available at Institute headquarters. All the papers are on file in public, university and technical libraries, and when so indicated in the list, may be found in the TRANSACTIONS. Copies of these papers have been mailed to those members of the Institute who are registered in Classes A-Mining Methods; B-Milling and Concentration; C-Iron and Steel Division; D-Non-ferrous Metallurgy; E-Institute of Metals Division; F-Coal Division; G-Petroleum Division; H-Non-metallic Minerals; I-Mining Geology; K-Mining Administration; L-Geophysical Prospecting, respectively. Other members may obtain copies by writing to the Secretary. Additional copies are sold at the rate of 1 cent per page; minimum charge, 25 cents. METAL MINING TECH¬ NICAL PUBLI- TITLE AUTHOR MEETING TRANS CATION VOLUME No. AND PAGE* 264-A.29. Quicksilver Industry in 1929. Im- L. H. Duschak San Francisco T30, 283, 312 provements in the Metallurgy of C. G. Maier and Oct., 1929 Quicksilver and Symposium on The others Present Status of the Quicksilver Industry (With Discussion) (37) 271-A.30 Observation on Ground Movement R. E. Palmer New York T30,168 and Subsidences at Rio Tinto Feb., 1930 Mines, Spain (20) 274-A.31 Development and Installation of the C. L. Berrien New York T30, 139, 166 Hawkesworth Detachable Bit (29) . Feb., 1930 276-A.32 Protective Measures Against Gas O. A. Glaeser New York T30, 129, 187 Hazards at United Verde Mine (11) Feb., 1930 287-A.33 Use and Cost of Compressed Air (12) R. S. Lewis New York Feb., 1930 314-A.34 Miami Copper Company Method of F. W. Maclennan New York T30, 39, 80 Mining Low-grade Orebody (44) Feb., 1930 319-A.35 How Human Beings Respond to W. J. McConnell New York Changing Atmospheric Conditions Feb., 1930 (9)

Jan 1, 1930

By H. H. Schrenk

[A colorimetric method5/ for the determination of benzene in amounts as low as 0.001 mg has been developed recently at the U.S. Bureau of Mines Pittsburgh Experiment Station by the authors, with the assistance of chemical personnel fro a the Allegheny County (Pa.) Relief Works Division. The method is based on the direct nitration of either liquid - or gas - phase benzene, followed by neutralization, extraction with butanone, and final treatment with sodium hydroxide which produces a violet color. The color is matched with color standards of known values. Although the method is adaptable to many conditions the primary objective was a procedure that would be suitable for hygienic investigations. The development worth included a study of possible interference by chemicals that be present in those situations in which the method. would be employed. In this study it was found that a specimen of hexane prepared by the Gulf Research Laboratory, Pittsburgh, by fractionation of West Virginia natural gas gave positive result for benzene, whereas a specimen of pentane prepared in the same manner showed only a trace, and specimens of n -heptane and octane (2,2,4 trimethylpentane) supplied by Eastman Kodak Co. save a negative result. According to information obtained from the Eastman Kodak Co. the latter two compounds were highly purified, the n-heptene being prepared from line and the octane synthesized in the laboratory. On nitration of a larger amount of tae natural hexane a visible quantity, of needlelike crystals which resembled those of m-dinitrobenzene was obtained. The hexane from this nitration was recovered by distillation and again nitrated, but no crystals or colorimetric indication of benzene was obtained. This imitated that the specimen of natural hexane contained a substance which at least had the chemical behavior of benzene.]

Jan 1, 1935

By L. Gasser, N. Bellinger, H. Awatta, A. Merati

As aircraft age, the extent of interactions between fatigue and other damage mechanisms, such as corrosion and fretting, increases. At present, however, there is no generally accepted methodology within the Aircraft Structural Integrity Program (ASIP) framework to account for the effects of these interactions on life and the residual strength of aging aircraft components. A comprehensive program is being carried out by the National Research Council Canada in collaboration with Analytical Processes/Engineered Solutions, using the Holistic Structural Integrity Process (HOLSIP) to address time and cyclic load issues. This approach predicts the evolution of a discontinuity state in a material from production to retirement. This paper summarizes the results of a study on the 2024-T3 aluminium alloy in different forms (clad and unclad), thickness, and specimen geometry. This study consisted of identifying the microstructural features associated with crack nucleation sites and relating them to the testing parameters and fatigue life. Several coupons were fabricated and fatigue-tested. The fracture surfaces were carefully examined, and the physical characteristics of the microstructural features found near the crack nucleation sites were analyzed. Effect of stress level, loading direction, coupon geometry and surface condition on the number of crack nucleation sites, and fracture origin size has been discussed. Four distinctive mechanisms were found to be responsible for crack nucleation: for unclad materials constituent particles, oxide residue, surface irregularities and for clad samples the clad layer was the sole fracture origin.

Jan 1, 2006

By S. Kline

The compositions of metamorphic minerals of the south limb of the Dore Lake Complex have been determined by microprobe techniques. Mineral assemblages typical of the greenschist facies occur in Mg-rich bulk compositions, but in Fe-rich rocks albite-epidote amphiboli te facies assemblages occur. Low oxygen fugaci ties and a general paucity of metamorphic fluids prevailed in most of the complex, but a higher oxygen fugacity is indicated near the Chibougamau Pluton, and a local abundance of C0z and Cl in fluids near the pluton is suggested by the presence of scapoli te. The metamorphic gradient overprinted on the complex near the Grenville Front is apparent in mineral chemistries as well as by the appearance of garnet. Chlorite becomes richer in Mg, and iron is fractionated more strongly into hornblende. The amphibole also increases in Alz03.

Jan 1, 1984

By Marcus Nadler

WAGES in the United States, in spite of the wage freeze, have increased materially. Overtime payments have become standard practice in almost all industries. Now efforts are being made to place wages on an annual basis, and if this is adopted, it will result in an increase in the cost of production. Organized labor today is more powerful than ever before; union membership is large and steadily increasing, and in many instances membership in the union is a prerequisite to employment. The treasuries of many unions are strong as a result of the large membership and full employment. The unions, therefore, today are in a much better position than ever before to carry on long strikes. Politically, too, the unions are more powerful today than they ever were. On the basis of their strength, one may expect that some of the demands that the labor unions will make in the not distant future will be granted. It is, therefore, quite evident that before long, particularly when the curtailment in war production reaches about 40 per cent, this country will be confronted with a serious labor problem.

Jan 1, 1945

By Ralph B. Adair

The Bureau of Mines conducted laboratory and continuous pilot plant flotation tests to determine the feasibility of recovering commercial-grade mica from an Alabama graphitic-mica schist. Preconcentration of the ground ore on a Humphrey's spiral was employed to reject the heavy minerals and part of the quartz in a product virtually free of mica. The acid-cationic mica flotation process recovered over 89 percent of the mica in a product containing 98.7 percent mica. Grinding of the mica concentrate in a fluid energy mill produced a product with a bulk density of 12 lb per cubic foot.

Jan 1, 1969

By E. Watkins, J. C. LeRoy, A. Vivyurka

"TAILINGS REVEGETATIONWelcome to the Revegetation Session. My instructions are to introduce the Speakers and to provide a general introduction.I do the latter with humility not only because of a lack of personal experience or because tailings revegation is not well established technology, but because any general statement on a country or industry as diverse as the Canadian Mining Industry is bound to be wrong somewhere.Laying aside normal standards of accuracy I proceed as follows:In considering the question of tailings revegetation, one asks two basic questions:1. What ought to be done?2. What can be done?The first question can be broken down into three kinds of criteria or objectives:a) Legislativeb) Technicalc) AestheticThe first I leave to the politicians and the last I will avoid. Aesthetics is the philosphy of taste. It is concerned with the appreciation of things rather than what they really are. It is much easier to get into an argument on aesthetics than to get out of it feeling you have said something of consequence.Technical criteria can be divided into the following sub-objectives: 1. To isolate the tailings basin so surrounding land is not degraded. The first step here is stabilization of the surface to prevent wind and water erosion."

Jan 1, 1975