Search Documents

By John A. L. Campbell

Surface dependent processes, such as froth flotation and flocculation, are important or potentially important techniques for combating some of the current major problems in coal preparation. In order to correctly apply or imporve a surface dependent process, it is of paramount importance to understand the interfacial phenomenon, especially the double layer properties, exhibited by the solid. The specific objective of this research was to determine the properties of the bituminous coal/liquid interface by an electrokinetic method, streaming potential, and to relate the findings, wherever possible, to the existing unit operations of froth flotation and flocculation. The electrokinetic properties of both the whole coal and its lithotypes were investigated. As part of the total investigation, the role played in the double layer by the reagents commonly employed in the surface dependent process was also established (1). These data will be presented at a latter date.

Jan 1, 1969

By AIME AIME

OUR new Director from the 15th District is Robert W. Thomas; of Ray, Ariz., general manager of the Ray Mines division, Kennecott Copper Corp. In electing him to this office his fellow engineers pay tribute to his ability as an engineer and express appreciation for his service to the A.I.M.E. and its Arizona Section. ?Bob? Thomas was born April 1, 1886 at St. James Minn. received his early education in the public schools of Topeka Kans. and was graduted from Topeka High School in 1905. Already he had decided upon mining engineering as a profession. so he entered the mining school of the University of Kanas from which he was graduated with the degree of B.S. in hlining enginrering. While in college he became a Student Associate of the A.I.M.E. After graduation, lution and isolated mining camps wel-e not the most desirable places in w

Jan 1, 1944

By John Hayden

The nation runs on energy. It is essential for the economic growth and national security of the United States that the nation has an adequate, sustainable, environmentally acceptable and economically viable balanced supply of energy sources, (e.g., coal, petroleum, nuclear, natural gas, solar, wind, geothermal, biomass, hydroelectric power). Therefore, the allocation of mineral raw materials to the energy-producing sector of the economy must be a top priority that requires the total demand for energy-related materials be judged in terms of domestic supply (Fig. 1).

Jan 1, 2012

By Keshab Sharma, Jibendra Misra

Caissons and piles are mostly used as foundation types in bridges. Caissons are particularly suitable for bridges with expansive spans, locations with deep alluvial deposits, soil prone to lique- faction and when there's a notable risk of vessel collisions. However, they face challenges related to sinking and limited resistance against earthquakes. On the other hand, pile foundations are not well suited for deep-water scenarios due to their excessive length, diminished rigidity, susceptibility to vessel col- lisions and complications associated with construction. A potential solution to the issues mentioned above could be the adoption of CCPF. These foundations can also be applied to enhance existing caisson. foundations through retrofitting techniques in wind turbines, trans- mission lines and bridge foundations, demonstrating their adaptability and potential for improving the perfor- mance of foundation systems. There has been successful implementation in China, as evidenced by projects like the Qiongzhou Straits Bridge and the Longna Highway Yangtze River Bridge. Moreover, this foundation approach has been adopted for numerous cross- sea bridges globally, including ex- amples like the Benicia Martinez Bridge (U.S.) and the Hitsuichi-Jima Bridge (Japan). Research from 2016 has shown CCPF systems can be potentially used for offshore wind turbine foundations and retrofitting existing caisson foundations. The construction sequences of CCPF systems involve the sinking of caissons followed by driving the pile beneath the caisson. There are two possible options for connecting the pile with the caisson. The first option can be provided by ending the pile at the bottom plug level of the caisson, in which the pile is threaded into the caisson bottom to achieve a connection joint between the caisson base and the pile tops. This methodology enhances the flexibility of the foundation. The second method is to continue the pile up to the cap level of the caisson. The pile up to the cap level of the caisson provides better integrity than the first option between caisson

May 1, 2025

By Robert S. Sanford

The Broughton and Ring magnetite deposits in Essex County, N. Y., are thought to be in a mineralized belt that extends from the Lake Sanford mining district to Lake Champlain and passes through the Mineville district. The country rook is syenite-gneiss, similar to that in the Mineville area. The Bureau of Mines conducted a vertical magnetometer survey of the area. On the Broughton properties there are no indications, magnetically, of magnetite in any degree of concentration. 'On the ding properties a number of sharp, localized magnetic anomalies were observed. One core-drill hole was bored to a, depth of 48.3 feet, also, to test one of the strongest anomalies. The field work was in progress from December 1943 to July 1944. Although no iron ore was intersected by' the drill hole, it showed that the amphibolite rook, at a depth of 6 to 100 feet below the surface, contained enough magnetite and iron sulfides to account for the anomalies recorded by the magnetometer survey.

Jan 1, 1949

The mining industry worldwide relies upon the identification of resources that can be economically developed and operated. Access to land is paramount through all stages of the exploration, development, operation and rehabilitation stages. Clear rights to use of land for the purposes of mining must be available and protected throughout the life of the project. Stable and enduring criteria for mining of the resource, once identified, are required to attract exploration and development expenditure. The purpose of this paper is to investigate the varying approaches to granting access to land for use for exploration and mining development, including the processes by which a project is approved by community and government and the time scale for such approval. The paper concentrates on the legal issues arising throughout this process. The law is stated as at September 1997.

Jan 1, 1997

By C. F. Vos, J. D. Miller, J. C. Davidtz

Small replacements of C12-trithiocarbonate (C12-TTC) for dithiocarbonate (DTC)/dithiophosphate(DTP) in a reagent suite for the flotation of platinum group metals (PGM) have significantly improved the rejection of gangue. Coupled to this is an improvement in kinetics, grade and recovery of PGMs. In a pilot-plant trial, after a 5 mole per cent replacement of the current DTC/DTP collector combination by C12-TTC, large opaque bubbles were replaced by small clear ones. In addition, a similar flotation response was realized with one-third of the current depressant dosage. During a preliminary plant trial on underground UG2 ore, the initial rougher concentrates were characterized by higher PGM concentrate grades and this was in part due to improved chromite rejection. The concentrate produced from the TTC trial also exhibited a much finer particle size distribution. The overall circuit performance, which included secondary regrind and flotation, showed an increase in concentrate grade of approximately 44% while the tailings grade remained unchanged

Jan 1, 2006

By John J. Mulligan

Ear Mountain is an isolated mountain mass that rises abruptly from the coastal plain on the northwest shore of the Seward Peninsula. Geologically it resembles the more accessible Brooks Mountain and Cape Mountain areas to the southwest, being composed of a granitic core surrounded and partly capped by metamorphosed sediments. The occurrence of lode- and placer-tin deposits in this area has been known since the early 1900's, when the Seward Peninsula region was prospected extensively for both gold and tin. The Federal Bureau of Mines investigated the tin deposits in the Ear Mountain area during the 1953 and 1954 field seasons. The objectives were to delimit the areas in which tin minerals occur, as a guide to future prospecting, and to determine the amount of tin in the known prospects. Work by the Bureau of Mines included both placer and lode sampling.

Jan 1, 1959

By G. O. Prickett, P. Somasundaran

An experimental progmm based on statistical principles is used for optimizing a flotation operation for the separation of minerals. In this case, flotation of sylvite from sylvinite ore with amine and starch as the flotation reagents was studied to find the optimum reagent levels at various slime levels. The experiments were first done on a two-level three-factor design. Analysis of the results showed that the interactions between various factors were significant. Hence, a first-order linear model of the flotation response would not be accurate. The two-level three-factor design was expanded into a composite design in order to test the fit of a higher-order model. Data were treated to obtain an expression for flotation response as a function of the different variables, to predict the optimum reaaent levels at various slime levels, and also to determine the path of steepest ascent. Tests around the predicted optimum and along the path of the steepest ascent were done until a near-optimum region was obtained. Exploration of the nature of the response surface in that region established the actual location of the maximum response. The optimum amine level was found to be 0.20 lb of amine per ten of ore at all slime levels, while the optimum starch level varied as a function of the slime present. Computer access at the laboratory by means of a teletype terminal on a commercial time-sharing system enabled efficient and accurate treatment of experimental data. The efficiency of experimental investigations can be improved significantly by the use of experimental design and data analysis based on statistical principles. The common approach used in experimental research is to study a property of a system as a function of "one-variable-at-a-time". Several authors'-4 have pointed out the inadequacy and deceptiveness of this method. Results obtained for the effects of a variable on the measured response of the system using

Jan 1, 1970

By R. Hogg, R. H. Weiland, P. Bunnaul

The dewatering of flocculated clay suspensions by compression in a centrifugal field was investigated. The results were analyzed with respect to the direct applicability of centrifugal dewatering (as in solid-bowl centrifuges) and indirect applications to gravity sedimentation systems. An important objective of the study was to evaluate the self-weight effect using centrifugal forces to simulate consolidation of deep sediments. Experiments were conducted in which the sediment mass and initial structure were maintained constant while the effective sediment weight was varied by centrifuging at different speeds. The relationship between the limiting sediment density and the applied consolidation stress was found to be the same for both gravity and centrifugal consolidation, indicating that small-scale laboratory tests can be used to predict consolidation in deep beds. The effects of the initial structure were also studied using controlled variations in flocculation conditions. The results imply that, for the flocculated suspensions studied, the longterm consolidation behavior is relatively insensitive to the actual extent of flocculation.

Jan 1, 1995

By William C. Alden

A great landslide occurred on June 23, 1925, in the valley of Gros Ventre River, about 35 miles south of Yellowstone National Park (Fig. 1). The relations of the north-easterly dipping rock formations of the slide scarp and of the dam formed by the slide are shown in the diagrammatic cross-section of the valley (Fig. 2). This generalized section is based on unpublished maps and notes by Eliot Rlackwelder, in the files of the IT. S. Geological Survey. Heavy rains and melting snow in the Gros Ventre Mountains had saturated clay layers in the Carboniferous strata, which dip toward the valley at angles of 18" to 21°, consequently an enormous mass of rock at the end of the north spur of Sheep Mountain became loosened and, on the afternoon of June 23, slid suddenly down into the valley. Within a few minutes this mass of debris—estimated as 50,000,000 cu. yd.—carrying

Jan 1, 1928

Canada's newest low-grade porphyry copper mine, Gibralter Mines Ltd. (N.P.L.), has reached production. The subsidiary of Placer Development Ltd., located at Williams Lake in the Caraboo District of central British Columbia, began open pit mining in mid-June on reserves estimated at 358 million tons assaying 0.373r: Cu and 0.016C; MoS,. Each of four separate zones will be mined in a predetermined sequence, in one or more stages, and with a throughput of more than 36,000 tpd. The sequence and stages of mining the zones have been determined by computer calculation and economic analysis and are designed to maximize recovery and minimize cost. At the very least, the mine is off to a promising start. Development costs leveled off at $67 million. 9'; below the anticipated budget.

Jan 7, 1972

By C. H. Bucknam

Principles of Green Chemistry provide useful guidance for sustainable mineral process development. Laboratory bench scale testing was carried out using pregnant cyanide leach solutions, and a number of commercially available mercury precipitation reagents were compared using jar testing to determine the most efficient and selective reagents for mercury precipitation. The most efficient reagent identified was sodium polymeric thiocarbonate (NaPTC).Coagulation experiments with fine diatomaceous earth resulted in a stable precipitate, with good settling properties. On line monitoring of the mercury in solution is recommended for process implementation to conserve reagent removing approximately 90-95% of the mercury with minimal silver and negligible gold losses.

Jan 1, 2004

The different stages of the metallurgical evaluation of an ore resource and their importance to overall project evaluation are described. Particular emphasis is placed on the liaison that is necessary between the different members of the project team from the preliminary exploration phase through to the completion of the final feasibility study. Metallurgical input at the earliest stage is recommended. The incorporation of metallurgical and marketing data into ore reserve statements and the effect of the metallurgical evaluation on ore reserve classifications are discussed.

Jan 1, 1987

A high strength steel strand bolt has been developed by Barrett, Fuller & Partners as a replacement for conventional rigid bars for primary roof support in coal mines. It is based on a 23mm diameter multiwire steel strand with a tensile strength of 55 to 60 tonnes, The paper summarizes the development of FLEXIBOLT flexible roof bolts, their reinforcement performance and their potential to provide operators, currently reliant on medium to high density roof bolting systems, with a viable, low density roof bolting system offering high roof reinforcement capacity along with the option of installing bolts longer than headroom, in a single pass at the face.

Jan 1, 1993

By Mel J. Laurila

The application of on-line ash analyzers in coal processing has become widespread. However, the analyzers are employed largely in monitoring, blending or sorting applications. Just recently has work begun on using on-line ash, moisture and/or solids data for plant control; and even more recently for localized circuit or unit operation control. Process Technology, Inc. (PTI) has since 1990 placed several bulk coal and slurry analyzers in practice where Fuzzy Logic Control (FLC) loops are used to manipulate controllable variables in real time. This technology is now being advanced by PTI. Unit operations where FLC has been employed in feedback loops using on-line ash analyzers include: heavy media vessels, cyclones, concentrating tables and froth flotation. The design, implementation and improvements attainable in preparation plant control using on-line ash analyzers are outlined in this paper.

Jan 1, 1995

By Joseph Singewald

THE problem of the utilization of the low-grade red iron-ores has peen before the iron-mining industry of the South for several decades. the experiments by W. H. Coghill1 of the U. S. Bureau of Mines to determine the degree of liberation of minerals in the Alabama low-grade red iron-ores after grinding interest the writer very much because 10 fears ago, while a member of the U. S. Bureau of, Mines, he experimented similarly on the same ores using a heavy solution .2 Extensive experiments were made in the nineties by W. B. Phillips3 in association with H. A. J. Wilkens and H. B. C. Nitze. The ores were rushed to pass 15 mesh and were separated by magnetic machines into concentrates, middlings and tails. The experiments were made with carload lots in an experimental mill. Most of the ores tested, however, were soft, whereas the main problem is the utilization of the low-grade hard ores. Phillips gives the results of only four tests of hard ores; two of these are of self-fluxing ores of the grade now utilized and two of ower grade and less amenable to concentration than the average low-grade ore that underlies the self-fluxing ore of the Big Seam. The average of these least favorable samples shows the production, from an ore analyzing 32.30 per cent. Fe, 10.34 per cent. CaO, 33.40 per cent. insoluble, of a concentrate with 43.82 per cent. Fe, 8.90 per cent. CaO, 18.48 per Sent. insoluble with a ratio of concentration of 2 and an iron recovery of 39.2 per. cent. The grade of this concentrate compares favorably with the average grade of washed brown ores of the district which is given by Burchard4 as 45 per cent. Fe, 14.6 per cent. Si02. The slightly lower iron

Jan 2, 1927

By A. R. Guest, R. Clayton, J. Jakubec

"The potential for mudrushes is a potential hazard that should be evaluated during cave mining studies. Mudrushes are a phenomenon that can have very different origins, but produce the same results: injury, loss of life, damage to property, excess dilution, production delays, or mine closure. Although mudrushes are more common in cave mines than other mines, any mining activity that enables the accumulation of fine particles and water is susceptible to mudflow. This paper describes the process developed by the authors during the past decade to evaluate the risk of mudrushes, specifically in caving and sublevel caving mines.RÉSUMÉ Un danger potentiel qui devrait être évalué durant les études d’exploitation par blocs foudroyés est la possibilité d’afflux de boue. Le phénomène des afflux de boue peut avoir des origines très diverses; les résultats sont cependant les mêmes : des blessures, des pertes de vie, des dommages à la propriété, une dilution excessive, des délais de production ou des fermetures de mines. Bien que les afflux de boue soient plus fréquents dans les mines exploitées par blocs foudroyés, toute activité minière qui permet l’accumulation de particules fines et d’eau est sujette à des coulées de boue. Le présent article décrit le processus développé par les auteurs au cours de la dernière décennie pour évaluer le risque d’afflux de boue, surtout dans les mines exploitées par blocs foudroyés et par sousniveaux foudroyés."

Jan 1, 2016

By R. V. Ramani, C. B. Manula, A. Owili-Eger

All the input data required to operate the ventilation simulator except the title, are entered with I10 or F1O.O formats. The title is entered with (18A4) format. The floating points are designated by (FP) and the integers by (INT)

Jan 1, 1975

By Ying Lu, Jeffrey C. Johnson, Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

The amount of energy used to break rock is of interest in mine-to-mill operations to minimize energy consumption during blasting at the mine site and comminution at the processing plant. In this research, a direct energy measurement was made using high-velocity impact to cause breakage of long granite cores, and to study the energy dissipation along the entire bar length. The results show the formation of three zones of damage — fragmentation, fracture and elastic — that have been characterized in 3D using X-ray tomography. The fragmentation zone of the granite bars was studied in detail to describe the particle size distribution and the particle shape characteristics. The experimental energy dissipation in the fragmentation zone was found to be in close agreement with the expected energy calculated from the Bond work index (BWI) equation [1] when the anisotropic granite particles in the fragmentation zone are defined by length rather than by sieve size. The results increase our understanding of rock breakage and energy consumption and may find future applications in mine-to-mill operations.