Search Documents

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period Oct. to Nov. 10, 1915: Lester S. Thompson, New York, N. Y. Arthur L. Sweetser, Boston, Mass. William Reed, El Oro, Mexico. Dorsey A. Lyon, Salt Lake City, Utah Heinrich Ries, Ithaca, N. Y. D. W. Blaylock has resigned his position with the St. Joseph Lead Co., Bonne Terre, Mo., and has accepted the position of division engineer for the Big Creek Coal Co., of Chicago, at Harrisburg, Ill. R. B. Lamb announces the removal of his office to Room 1809, 43 Exchange Place, New York, N. Y. C. C. Sanders has taken a bond and lease on the Red Mountain group of 34 mining claims (copper), Patagonia, Ariz., and has commenced extensive development.

Jan 12, 1915

By J. Esterle, J. Kruttschnitt

Fragmentation modelling in soft rocks presents a challenge due to their propensity to further fragment after blasting during normal handling. Coal and some iron ore deposits are examples of materials that undergo significant degradation during the extraction, hauling and dumping process of the mining operation. The Kuz-Ram model is an empirically derived predictor of size distribution from blasting hard rock. Little breakage occurs during excavation and subsequent sizing of hard rock, so the measured Run of Mine (ROM) size distribution is essentially the same as the post-blast (before excavation) size distribution. However, for soft rocks, each step of the excavation and hauling operation imparts energy to the rock particles so the measured. ROM size distribution will be significantly different from the postblast size distribution. In order to calculate the ROM fragmentation at any stage of the extraction (or sizing) operation, the JKMRC has developed a model that combines both blast fragmentation and degradation through subsequent handling.

Jan 1, 2001

By Gopalan Ramadorai

This paper presents a review of halogen solvents used in the processing of precious metals. Reagents of widely varying chemical structures, such as chlorine gas, calcium and sodium hypochlorite, chlorine dioxide, iodine and bromine have been used for precious metal extraction. None of these chemicals are a replacement for cyanide: however, each of these chemicals present an opportunity for use in processing a specific type of ore. The ore and chemical must be matched to each other for success. Recovery of metal from the leach solutions also offers challenges.

Jan 1, 1994

By R. J. Gochin, G. D. Schena

Mineral processing options and technical innovations should be financially assessed. Indeed technical feasibility alone does not offer an adequate process selection criterion. An appraisal by the use of engineering economics principles leads to a more efficient evaluation and selection of feasible mineral processing solutions. Financial consequences of different options synthesised by profitability indices allow better decision making. Selected examples derived from real world problems are used to illustrate the potential of engineering-economics methods applied to mineral processing.

Jan 1, 1995

While great strides have been made in the machinery for mining rock on the surface of the land, comparable advances have not been made with underground equipment. In fact, excavation of underground openings has actually declined in importance. On the other hand, surface mines are getting deeper and approaching the economic limits at which they can be worked. In the face of these approaching limits and the added problem of escalating labor costs, James Boyd, President of Copper Range Corp. and AIME, has suggested that "science and engineering must come to grips with the need for making subsurface openings more quickly and cheaply.

Jan 10, 1969

By A. J. Opinsky

MANY investigators, in their discussions, have reasoned that the ductile-brittle transition in iron could be explained by the intrusion of cleavage into the normal slip process. The purpose of this note is to apply the laws of critical normal stress for cleavage and critical shear stress for slip to explain the orientation and temperature dependence of the ductile-brittle transition in body-centered cubic metals. It will be found that within a certain temperature range, single crystals tested in tension will cleave or slip, depending on their orientation. Some data recently appearing in the literature will be analyzed from this standpoint. For a single crystal with [uvw] parallel to the tensile axis, the resolved shear stress on the slip

Jan 1, 1954

By W. Robert Power

Petrographically these range from true granite and syenite to gabbro and anorthosite. Commercial limestone is any sedimentary rock composed predominantly of the minerals calcite and/or dolomite. Commercial marble is any crystalline rock composed predominantly of calcite, dolomite or serpentine that is capable of taking a polish. Marble comes in a wide variety of color, texture and pattern. Many commercial marbles are unmetamorphosed limestone, to the geologist or petrologist but if they take a polish, are classified as marble.

Jan 6, 1972

By William P. Blake

THE importance to the growing steel industry of the United States of a domestic supply of ferro-manganese or "spiegel" of a high grade, induces me to bring to your notice some details of the method by which a superior article is produced in the Austro-Hungarian Empire. At Reschitza, Hungary, and probably at Laibach also (the Krainische Industrie Gesellschaft), ferro-manganese is made in a blast-furnace, with charcoal as fuel, and limestone as the flux. The ore is a ferruginous mixture, containing about 37 per cent. of sesquioxide of manganese. It is silicious, and somewhat resembles, in its appearance, the manganese ore from Red Island, in the Bay of San Francisco, California. It contains about 29 per cent. of silica and some alumina, shown by the subjoined analysis

Jan 1, 1876

By C. Pelley, S. Kelebek, G. Kunzel, P. Katsabanis

Small blocks of granodiorite have been subjected to blast loads from a single borehole and from a series of boreholes detonating at various timing intervals. The damage of the blocks was assessed through P-wave velocity monitoring, measuring the change of the point load strength index of the rock after dividing the large blocks into smaller ones and measuring the work index of the material at different distances away from the blasthole. Numerical modelling with the AutodynTM code enabled visualization of damage. It was shown that damage is optimum at a small delay time between successive holes while it drops rather drastically after this point.

Jan 1, 2003

By Alastair J. Sinclair, Asger Bentzen

Abstract - A simple linear model for interpreting duplicate analytical data for a range of values is described. The conceptual model can be quantified using a reduced major axis model rather than the inappropriate traditional least squares approach. The reduced major axis parameters (slope, intercept) and associated errors provide a quantitative basis for: (1) defining bias, and (2) comparing results within laboratories, between laboratories and between sampling/analytical methods. Application of the linear model must be preceded by extraction of obvious outliers or small groups of values that have an inordinately large impact on values of the statistical parameters defining the model. In addition, consideration must be directed to the presence of more than one population of sampling error, as in the case of multiple styles of mineralization being sampled.

Jan 1, 1998

By Warren K. Kourt

Many important discoveries of mineral deposits have been made as a result of routine exploration for oil and gas. Through the presentation of three hypothetical case histories, including cost data, the author shows how mineral evaluation can be performed during routine petroleum drilling operations and how mining companies and oil companies or oil operators can cooperate in such endeavors.

Jan 1, 1972

By B. R. Palmer, G. Gutierrez B., M. C. Fuerstenau

Flotation responses of chrysocolla and rhodonite are correlated with electrophoretic mobility and infrared spectroscopy measurements. Flotation is effected in the pH ranges in which hydrolysis of the metal ions comprising the mineral occurs. The roles of mineral solubility and precipitate formation are suggested.

Jan 1, 1976

By José C. Escobedo B.

A kinetic study of nitrogen dissolution in a. electromagnetically stirred Co-Cr-Mo alloy bath was made. The experiments were carried out at 1693, 1723 and 1743K of temperature, with a nitrogen pressure of 0.67 atm. The mass transfer coefficients were obtained, finding that their values increase as temperature grows. The true kinetic constants were calculated. It was found that at 1693K of temperature, the kinetics of the nitrogen dissolution process is controlled by a mixed mechanism involving both transport processes and chemical reaction, while at 1723 and 1743K of temperature, the kinetics is controlled only by transport processes mechanisms.

Jan 1, 1995

By Greg Barfoot, Alex Harrison

Conveyors with multiple drive pulleys of the same diameter and wrap, driven by identical motors through gearboxes of the same ratio, consume different powers. The fundamental issues related to this problem hinge around the drive pulley co- efficient of friction and the intermediate tension. Some basic design concepts will be presented with reference to validity and applicability. The paper will describe some experimental results obtained from multiple drive conveyors in which the drives are spatially separated. The dynamics of tripper drive and linear booster drive systems are overviewed with reference t

Jan 1, 1993

By Rana P. Singh

Electrolytic metal reduction operatios in both aqueous and molten salt electrolytes are being studied by digital signal analysis. The purpose is to determine the relationship between the physical processes occurring in the cell and the frequency spectrum of the cell's fluctuating electrical parameters. The fast Fourier transform of cell voltage (in galvanostatic operations) or cell current (in potentiostatic operations) is computed on-line in real time for the electrorefining of zinc in aqueous acid chloride solutions.

Jan 1, 1984

By Whiteley M, Robinson T, Vernon B

The Western Australian gold industry has approximately 100 operating plants, mainly CIP/CIL. The nature of the State's rapidly expanding gold industry gave rise to concerns over management of the cyanide hazard, in that most plants are remote from major population centres, have a workforce with a high turn over and use highly saline process water. Approximately 4,500 workers in the industry have the potential to be exposed to cyanide in the course of their normal work.This paper outlines the risk management strategy developed by Government and industry to monitor atmospheric HCN gas in the work environment and the role of continuing education and training along with regular site inspections by Department of Mines Inspectors.

Jan 1, 1990

By I. J. Jansen, C. L. Hooks

Successful soil construction involves prepa¬ration of an adequate base, selection of high quality soil ma¬terials, and placement of those materials by means which will establish a continuous macropore network and modest to low soil strength. Where such has been accomplished, experi¬ments reveal row crop productivity on reclaimed land which is very competitive with that on undisturbed land. Inferior productivity and sensitivity to drought stress are experienced where the soils are excessively compacted during construc¬tion. Some deep tillage practices have been quite successful in improving the compacted soils, but it is preferable to avoid compaction as the soil materials are handled.

Jan 1, 1987

By J. B. Gwiazda

This work contains a description of a new design of lemniscate-guided powered roof support units, with a discussion of currently designed supports and their interaction with the roof. Conventional roof supports of this type present a serious reaction with the roof because of the horizontal displacement of the canopy in the course of decreasing support height as the support takes weight. The new design presented eliminates previous disadvantages of lemniscate supports and ensures proper performance of the latter in relation to the roof of a mine working.

Jan 1, 1986

By R. D. Coleman, A. E. McIlhinney, C. E. Capes

Problems of unstable operation in continuous balling circuits may be traced to the random generation of seed agglomerates. This has been verified during the continuous operation of a laboratory balling drum with internal recycle described previously by the authors. The cyclical behavior of a balling circuit was also investigated using a simple numerical computer model. Changes are suggested in the design of balling equipment to improve stability.

Jan 1, 1976

By Allen V. Reicks

This paper reviews the impact of the idler set on the performance of belt conveyors. Idler rolls as part of the load support system and their interaction with the conveyor system will be discussed. in particular, the rotating performance of the individual idler roll concentrating on the rotating resistance and life of the bearing and seal design are addressed in detail. A basis for the development of performance specifications for use in conveyor design that takes advantage of the idler manufacturers design and manufacturing expertise is discussed.

Jan 1, 2008