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By F. F. Schmidt, H. R. Ogden, E. S. Bartlett

ThE solubility of carbon in tantalum has been reported to be very low at temperatures below 1500 C,1'2 increasing to at least 0.02 wt pctl at the eutectic temperature of 2800°C. The solubility limits at low temperatures were based on metallo-

Jan 1, 1963

By A. M. Gaudin

It is only in recent years that substantial progress has been made in developing a physico-chemical picture of the solid state. The molecular concept, so useful in dealing with gases, was naturally carried over to the field of crystalline solids; it has resulted in the firm implanting of erroneous concepts that only now are being eradicated successfully. Two simply written and effective books on the subject are Crystal Chemistry by Stillwell' and An Introduction to Crystal Chemistry by Evans. A more complete treatment of the subject is available in a book by Wells. The monograph by Hucke14 also touches on a subject most easily perceived by reference to the brief introduction by Bragg; that master of the field. These texts make it clear that while some solids are built of molecules, many are built of ions, others of atoms connected in the form of giant molecules, and still others of cations and electrons. The various lattices in which these entities are systematically arranged, the joint use of several of these entities, and the transitional character of some of the bonds make for the great variety of crystalline solids. The purpose of this paper is to point out a most important corollary of present views on the structure of solids. In this connection the classification of solids in Table I is helpful.

Jun 1, 1955

By Harrison Schmitt

IN the practice of ore finding the geologist is continually confronted with the question of oreshoot extension, so that the general problem seems worthy of systematic investigation. This problem appears when the reserves are estimated and when the advisability of deepening the shaft comes up. Moreover, there is need for lower development cost to keep pace with cost reductions in other departments, or even to offset a rising cost of ore finding or ore following. This can be gained by close geologic control of the development; and much of the geology involved is that bearing on the downward, upward, and horizontal extensions of shoots. Furthermore, the purchase of a mine or prospect often depends directly on the question of shoot extension; because it is seldom that the ore is fully developed and the purchase price is almost invariably based largely on "possible" and geologically prospective ore. Most current methods for estimating "possible" and the more nebulous classes of ore are crude and indecisive. In the following pages the extension of oreshoots is the major theme, although the more basic subject, the general art of ore finding, is given some space.

Jan 1, 1929

By R. Haldenwang, R. Erasmus, P. T. Slatter, R. P. Chhabra

Notches are used routinely for measuring the flow rate of water with free surface flows. As far as can be ascertained, no work has been done to investigate the performance of these flow rate measurement devices for non-Newtonian suspensions. The Flow Process Research Centre at the Cape Peninsula University of Technology has investigated the flow rate of kaolin and bentonite suspensions from a tank for two notch shapes, namely rectangular and triangular, and for 3 different concentrations of each suspension. The notches were calibrated using water and then the kaolin and bentonite suspensions were tested in them. The rheological characterisation of the fluids was done with a Paar Physica MC-1 rotary viscometer fitted with a cup and roughened bob. Analysis of the results shows a significant increase in discharge coefficient with increase in concentration, and the discharge coefficient has been correlated to the yield stress. This is the first such study, and further investigation is needed to confirm and extend these findings.

Jan 1, 2007

By B. T. Wykoff

This paper describes an important function of mining in Southeast Missouri. The practice is a necessary procedure to prevent disintegration of the pillars. Although the technique is peculiar to this district, it might have application in other mines using room and pillar method.

Jan 8, 1950

By M. Prasad, G. M. Rao, T. C. Rao, A. K. Majmudar

A two-step flotation scheme was employed to beneficiate a low-grade, cherty-calcareous rock phosphate ore from the Jhabua district, Madhya Pradesh, India. In the first stage, apatite and calcite ire floated together to remove silica, and, in the second stage, calcite is floated and apatite is depressed. The reagent scheme consists of sodium oleate, sodium silicate, orthophosphoric acid and sulfuric acid. The effect of reagent dosages on the efficiencies of separtition in each stage was studied systematically. A flowsheet was proposed for the processing of a low-grade phosphate ore containing 12.5% P2O5, 26.5% SiO2 and a CaO/P2O5 ratio of 2.64 (=32% calcite). The proposed flowsheet would produce a composite phosphate concentrate containing 27.2% P2O5, 6.37% SiO2 and a much reduced CaO/P205 ratio of 1.66. The total P2O5 recovery for the composite concentrate would be 73% .

Jan 1, 1996

By R. J. Sweigard, G. T. Lineberry, B. K. Slone, F. A. James III, D. S. Maggard

The depth at which it becomes more economical to use slope access instead of box-cut access for nearsurface coal reserves is termed the "transition depth." The transition depth can be established for a given coal property by considering cost estimates for those parameters that determine respective access methods. Fourteen parameters that influence access cost were identified, and ranges for these parameters were determined. A transitiondepth formula was developed to permit the determination of which is the better method of accessing a reserve, given information such as high wall slope, road width, total bench width, pit dimensions, road grade, belt component costs, pumping costs and the cost of overburden removal and reclamation. In most cases in Appalachia, especially in eastern Kentucky, the observed transition depth ranges from 20 to 30 m (66 to l00 ft). This indicates that actual practice is consistent with the analytical approach used.

Jan 1, 2002

By R. M. Carland, F. F. Aplan

The ion-exchange capabilities of natural zeolites from the western United States, representing the species chabazite, clinoptilolite, erionite and mordenite, have been studied because of their potential use in environmental remediation and in hydrometallurgical processes. These raw zeolite samples were found to contain Na+, K+, Ca+2 and Mg+2 as exchangeable cations, and all of these, with the exception of Na+, were found to seriously interfere with the exchange of Cu+2 from solution. Placing these zeolites in the Na+ form was found to increase their cation-exchange capacity, often massively. In addition, the elution of Cu+2 from the Na+ pre-exchanged zeolite is greatly facilitated when the deleterious K+, Ca+2 and Mg+2 have been largely expelled. The relative influence of these deleterious ions on the uptake and elution of Cu+2 was determined.

Jan 1, 1996

By Z. Sartowski, M. J. Pearse

The authors present laboratory and plant results illustrating the benefits to be gained by using chemical additives, namely flocculants and surfactant dewatering aids, in the Bayer process. Advantages of synthetic flocculants over starch are illustrated in terms of more efficient solid/liquid separation in both the initial settling of blow-down slurries and in the CCD wash train. In addition, it is shown that the use of synthetic flocculants considerably reduce the levels of organic contaminants present in the process liquor. Secondly, very significant improvements in moisture removal were obtained by the application of dewatering aids to hydrate filtration/ washing operations.

Jan 1, 1984

By Lars Lövgren, Jörgen Jönsson

Heavy metals may be retained within deposits of sulfide minerals under oxidation and in the nearest recipients of drainage water by sorption to secondary iron precipitates. The extent of sorption is strongly influenced by solution pH and presence of complexing ligands, such as sulfate and natural organic acids. Desorption of metals and organidinorganic anions to recent secondary Fe precipitates, collected at the Kristineberg mine, Sweden, has been investigated under different geochemical conditions. Elemental composition and structural characterization (X-ray powder diffraction) indicate presence of schwertmannite. While metals such as Ni and Pb were fractionally desorbed from the precipitates under acidic conditions, oxyanions, e.g. arsenatdarsenite and sulfate were desorbed preferably under alkaline conditions. In a separate study the adsorption of NOM onto synthetic goethite was investigated. NOM adsorption showed a strong pH dependence, 95% was adsorbed at pH 3 and 40 % was adsorbed at pH 9. Addition of 2 mM of sulfate desorbed about 10 % of the adsorbed NOM.

Jan 1, 2000

By J. Bartrum, A. Bowler, G. Butcher

The purpose of this paper is to outline the design, specification, and operation of the 8.5-m- diam (28-ft-diam) SAG mill commissioned at Kidston Gold Mines during January 1985. Amenability of Kidston ore to SAG milling, coupled with substantial cost advantages, led to the specification of this mill, equipped with variable speed drive to overcome the large variation in ore hardness. Operation of the mill is effected via a number of automatic control loops. Problems experienced with automatic control plus other electrical and mechanical failures have led to design changes and the formulation of future operating strategies.

Jan 1, 1987

CORPORAL SHEPPARD B. GORDY Sheppard B. Gordy, a brief biography of whom was printed inn the January Bulletin, entered the employ of the Braden Copper Co. immediately on his graduation from the Sheffield Scientific School in 1912. He remained with this company four years, working up through the various grades to assistant foreman and foreman to one of the individual mines. The last year he was in its employ, he acted as general mine foreman. He was for a short time with the Chile Exploration Co. and then went with the Andes Exploration Co. (Anaconda) and remained with CORPORAL SHEPPARD B. GORDY. the latter, doing mine exploration and development work, until he sailed for home in June, 1918, to give a more personal and active service to his country in her need. He declined a tender of induction into an officers' training camp, at the urgent request of Professor McClelland supplemented by Mr. Potter, because they demonstrated to his satisfaction that he could give more valuable service to his country in helping out with the aircraft production. Being within the draft age, in order to carry out this plan, it was necessary for him to be called by his Local Board and sent to camp. This call came Aug. 26. Two weeks before that time lie had gone to Dayton, Ohio; to begin the study of aircraft production, and was sent by the Dayton Board to Camp Sherman, Chillicothe, Ohio, where he died of pneumonia on Oct. 9.

Jan 3, 1919

U.S. Signs Pact With Miami Copper Miami Copper Co., of Arizona has agreed to mine lowgrade copper ores in an extension of its Globe-Miami mining district operations at a guaranteed price of 27.35[] per lb, under a contract signed with defense Materials Procurement Agency. Terms of the contract call for delivery of 230 million lb of refined copper between 1955 and 1962. DMPA said highgrade ore in the de posit will soon be exhausted and it is considered advisable to have Miami continue the operation. The Government has an option to buy 120 million lb of refined copper from present production at market prices. Miami will develop the new ore- body at its own expense-estimated at $3 million. If losses under the new contract reach a specified point, Miami may cancel the agreement. The company plans to use the block caving method in the underground operation.

Jan 4, 1953

By P. Nelson, K. L. Gunsallus, A. R. Ingraffea, J. F. Beech

INTRODUCTION Fracture toughness, KIC, is an intrinsic material property and is a measure of the energy required to create new surface area in a material. Fracture toughness measurements can be made for a wide range of rock types (Ouchterlony, 1980). As a measure of energy of comminution, fracture toughness might be used for more sensitive predictions of Tunnel Boring Machine (TRM) performance than are possible with other index measures in current use. This paper describes part of an ongoing, comprehensive, analytical/experimental program aimed at evaluation of KIC in such a role. The program includes efforts to: 1. Provide a firm analytical basis for a test specimen geometry: the core-derived short-rod. 2. Develop simple, inexpensive testing equipment and techniques. 3. Evaluate the accuracy of the above by testing rock and other materials and comparing the measured fracture toughness with those obtained by other methods. 4. Measure fracture toughness of a substantial number of different rocks from three ongoing TBM projects. 5. Compare fracture toughness results with other strength measures. 6. Compare all test results with observed TBM performance in the three projects. Presented here are summaries of all but the last of these efforts. Comparative evaluation of KIC as a more senstive rock property for TBM performance prediction will be the subject of the oral presentation and a subsequent paper.

Jan 1, 1982

By Alexander May

In this Bureau of Mines publication stability constants for complexes of diethylenetriamine, 2-aminoethyl sulfide, triethylenetetramine, and 1,8-diamino-3,6-dithiaoctane with copper, nickel, zinc, and cadmium were deter-mined. The amine complexes were found to be much more stable than the analogous thio complexes. The results are interpreted in terms of possible molecular structure of the complexes.

Jan 1, 1974

By C. H. Curtis

The Esperanza mine of the Copper Division of Duval Sulphur & Potash Co. is located in the Twin Buttes District, 32 miles southwest of Tucson, Ariz. Records of mining activity in this vicinity date back to the 1850's. The New Year's Eve mine, which was last active briefly during the years of World War II, made the first actual penetration into what is now Duval's Esperanza property. Duval's exploration department became interested in the Esperanza in the fall of 1954. The first test hole was started on May 8, 1955. Two years of intensive exploration work together with metallurgical studies developed the basis for the decision to establish an operation.

Jan 11, 1961

By Cindi Byrns, Andy Davis, Amy Tisdale

The Robinson district, Ely, Nevada is a hydrogeologically complex system with several distinguishable geologic blocks, each with a distinct background groundwater chemistry. To discriminate between background and mine-impacted groundwater, background wells, monitoring wells, pit lakes, waste rock seeps, and surface water samples were analyzed for a suite of major cations and anions, together with trace and precious metals, rare earth elements, 2H-deuterium and 18O/16O. The data allowed identification of groundwater flow paths, verification of hydrochemical source areas and characterization of natural attenuation mechanisms (e.g., mixing, dilution and mineral precipitation) that control the concentration and migration of metals at the site.

Jan 1, 2000

By K. Hanumantha Rao, P. K. Sharma

A pure strain of Paenibacillus polymyxa and mineral- adapted strains are used to bring about surface chemical changes on pyrite and chalcopyrite and, thus, theirflotation. Paenibacillus polymyxa was adapted by repeated subculturing in the presence of pyrite and chalcopyrite. The surface chemical changes of bacteria due to adaptation and of minerals after their interaction with bacterial cultures are evaluated by electrokinetic and infrared spectroscopy and are discussed with reference to their flotation responses. Interaction of bacterial cells, bacterial metabolites and whole bacterial cultures affected the Hallirnondflotation behavior of the sulfide minerals. The Xanthate flotation results show that pyrite, but not chalcopyrite, is depressed when the tests are carried out after interaction with chalcopyrite-adapted Paenibacillus polymyxa. This investigation demonstrated that the surface chemical properties of bacteria can be manipulated successfully to achieve the desired effects in the flotation process.

Jan 1, 2000

By William Reynolds

THIS paper deals with the results of a study of the application and development of mining machines for cutting out and removing dirt bands in bituminous coal beds. FACE PREPARATION When one or more dirt bands1 occur in a seam of coal, the problem of elimination of impurities becomes manifest. The degree of complete-ness to which these impurities are removed at the face has an important bearing upon labor costs, haulage costs and outside cleaning costs, and often the ash content of the product is markedly affected. Yet, because the present-day miner is paid for the number of tons he loads he often lacks interest in the quality of the coal. To insure a clean product, a system of penalties for dirty coal is enforced, but control of extraneous impurity content in the loaded coal is often inadequate and ineffectual when coal and banded impurity are shot as one. It seems only logical that to reduce the amount of impurities by proper face preparation before the men are permitted to load the coal is the most efficient method of preparation.

Jan 1, 1936

By Keith G. Wallace, Robert Wise, Ian J. Duckworth

This paper describes a case study for the ventilation planning at Utah Fuel Company's Skyline Mines which are located outside Price. Utah. The Skyline Mines are currently comprised of two longwall coal mining blocks located in two different mines. A third replacement longwall block is currently being developed. Future ventilation systems for the mines were determined by establishing ventilation models developed from data collected during a detailed ventilation survey. The paper discusses the challenge to coordinate immediate ventilation requirements with long-term demands. The continuous movement of the longwall, which frequently represented the only open split in the ventilation network, resulted in cyclic ventilation demands dependent upon the length of the tailgate. A series of system configuration changes were recommended based on the results of the network modeling exercise and an economic evaluation of the various options. The scope and cost of the configuration changes, and the mead improvement resulting from these changes is discussed.

Jan 1, 1995