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By Bruno Paponetti, Luigi Toro, Carlo Abbruzzese, Maria Y. Duarte, Anna Marabini

A bioleaching process has been developed to extract manganese from low grade domestic resources not amenable to conventional mineral processing operations. Between the different strains of microrganisms tested, Thiobacillus ferrooxidans has appeared poor over manganese, Aspergillus niger allowed to obtain high recovery, probably due to the metabolic production of citric and oxalic acids, showing a remarkable complexing and reducing action. The growth of microflora has been correlated to the MnO dissolution as confirmed by SEM observation.

Jan 1, 1989

By Corale L. Brierley

Bacteria have long been used for the extraction of copper during dump leaching of sulfide minerals and in the recovery of uranium from mined-out areas. However, bacteria can also be used in extraction of trace metals from copper ores and waste materials. Molybdenum, tungsten, nickel, cobalt, gold, silver, and other strategic metals can potentially be released from ores and wastes by biological processes. The chemistry and biology of these reactions, the potential for using the processes, and the state-of-the-art of the technology will be discussed.

Jan 1, 1983

By Wolfgang Baum

This paper discusses the use of mineralogical work during the develop ment and operation of gold heap leaching projects. It focuses on the early assessment and prediction of metallurgical performance, the identi fication of gold recovery problems and the application of mineralogy in process optimization. The results of extensive operations support work emphasize the benefits of routine plant mineralogy. Mineralogical characteristics are amongst the most important factors determining leach- ability, leach time, reagent consumption, insoluble losses, scale forma tion and equipment performance.

Jan 1, 1990

By Dan Kump

This paper provides an overview of Barrick Gold's Bullfrog underground mine backfill program. The Bullfrog underground mine was a gold mine that primarily used the underhand cut-and-fill mining method. The first portal was established June 18, 1991, and mining continued until Dec. 29, 1998. This paper begins with a discussion of the events that took place to reach about 1.8 kt/d (2,000 stpd) of backfill. It ends with a commentary of what was learned. The Bullfrog experience suggests that there are two essential factors to a successful backfill program: a well-graded aggregate supply and proper placing procedures.

Jan 1, 2002

By J. W. Oberholzer

Problems with gravimetric sampling have led to the establishing of a computer linked tyndallometer dust measuring system. Preliminary tests conducted with the system indicate that the system can be used to do correlative exercises between mining activities and dust levels. The system also allows occurrence characteristics of dust levels to be determined. Use of this equipment will enable dust allaying methods to be tailored to the specific underground situation.

Jan 1, 1987

By J. A. Herbst, L. B. Hales, R. A. Ynchausti

Industrial application, theoretical discussion and technical research programs continue to stimulate acceptance of column flotation. Numerous authors have published model, parameter and application studies discussing advantages and problems which are associated with this minerals processing technique. This paper dispells the myth of the self-controlling column while focusing on the problems and opportunities which are inherent in the computer control of a column flotation cell.

Jan 1, 1988

Already one of the premiere suppliers of mining equipment in the world, Bucyrus strengthened its position when it signed a definitive agreement to purchase Terex?s mining equipment business for $1.3 billion. Bucyrus? acquisition of DBT in 2007 made the company one of the leaders in the field of underground mining equipment to go along with its already solid standing as a surface mining equipment supplier of draglines and electric shovels. The acquisition of Terex mining will make Bucyrus a comprehensive supplier of mining equipment above and below ground. With the acquisition of Terex, the Bucyrus product portfolio will now comprise walking draglines, electric rope shovels, hydraulic excavators, haul trucks, a full line of drills (surface and underground), highwall miners, underground longwall, room-and-pillar and transport machinery, and belt systems for all mining applications. Bucyrus said its ?unmatched suite of surface and underground mining equipment will be paired with its superior parts, consumable products and after-market support throughout the world.?

Jan 2, 2010

By T. V. Vasudevan

Floc properties such as density, size, size distribution, porosity, and shear strength govern the effectiveness of flocculation as a process for solid-liquid separation. The floc characteristics desired for removal of suspended solids by sedimentation or filtration, for example, are known to he different. In this study, an attempt has been made to evaluate the effects of various physical and chemical factors on the density and shear strength of the flocs.

Jan 1, 1990

By Charles E. Scott

The molybdenum industry has been in a depression since the beginning of the decade. Real molybdenum prices are significantly reduced from 1979-1980 levels when there was a perceived capacity shortage and continued expectations of burgeoning demand. Primary capacity brought on stream since then has been unable to operate profitably and indeed, in light of high inventories and reduced demand, has been largely unnecessary. Structural changes in the molybdenum industry will be needed in the future to weed out superfluous capacity and to expand demand through new product applications.

Jan 1, 1986

By Henry R. Tiedemann, William H. Hansmire, Harvey W. Parker

Although the use of precast concrete segments for tunnel linings has been common for many years in Europe, acceptance of this type of lining has been slow in the United States. This paper explores the cost, design, and construction considerations of concrete segmental lining with a view to promoting its use in this country when favorable conditions exist. The different perspectives held by owners, designers, and contractors are discussed. In addition to cost, other considerations include previous design and construction experience, size, length and function of tunnel, watertightness, and liability. Cost comparisons are made to traditional ground support and lining. Under favorable conditions, the use of precast concrete segmental linings can be technically feasible and cost effective.

Jan 1, 1987

By R. J. Miller

The current US national commitment to expanding the human presence into the solar system will clearly require major facilities in Earth orbit or possibly on the Moon. Such facilities will need large amounts of materials for structural modules, life support, propulsion and shielding. The heavy transportation costs in fuel required to lift materials from the Earth's surface make a terrestrial-based space system inherently inefficient. A more cost-effective approach would be to provide as much of the required materials as possible from other bodies in space not having the high cost of Earth launch. This paper identifies potential targets for space-based resource utilization, constraints on exploitation and relative benefits of various sources.

Jan 1, 1994

By Paul Chamberlin

Management has assorted roles to play, many of which are listed, that may call for consultant input. Consultants also play various roles, and some of these are discussed as well. The relationship between management and the consultant depends mainly on management's preparation for the assignment and on their monitoring during the assignment. Consultant costs are discussed briefly and suggestions for keeping consultant costs under control are given. In addition, some qualities of a good consultant are covered.

Jan 1, 2001

By Persio de Souza Santos, Ayres Ferrelra Morgado

In this work, a sample (of about 100kg) of an ore considered as smectitic, not yet industrialized, from Lages-SC-Brazil, was tested for evaluation of its industrial applications. First, we characterize them by XRD, DTA, FRX, and CEC analysis. After this, the smectitic clay was changed to sodium form by treatment with sodium carbonate. Then, the homoionic sodium clay was tested for iron ore pelletizing agent, as binder of foundry sands, and drilling mud with good results.

Jan 1, 1998

By Charles D. Litton

This paper presents a description of the hazards of smoke from fires, the detectability of smoke using smoke sensors, and the operational characteristics of such detectors. It places in perspective the advantage that smoke detectors have over other forms of fire detection and also provides a discussion of smoke as a significant fire hazard.

Jan 1, 1992

By W. L. Han, Y. D. Zhang, X. C. Li

Meta-systhetic technique for large systems engineering has been placed on the agenda. The meta-systhetic A1 approach should involve the integration of digital and knowledge info, from qualitative to quantitative analysis, etc. Some algorithms of meta-systhetic technique such as ANN-ES and GA-ANN are introduced. A case study follows - mining conditions evaluation by meta-synthetic A1 methods, including: setting up the structure of evaluation indexes system, deciding their grade of membership by ANN-ES algorithm; determining the weight values of evaluation factors by GA-ANN algorithm; and developing the integrated evaluation model.

Jan 1, 2002

By Louis A. Sandbak

Drift excavation by boom-type roadheaders in the San Manuel and Kalamazoo sulfide copper ore bodies has been successfully demonstrated. Geomechanical rock classification in conjunction with detailed geologic mapping has been necessary to assess roadheader performance, and to predict advance rates in the varied rock classes in the San Manuel block caving mine. Rapid excavation and less fractured ground are obvious advantages of roadheader drift excavation over conventional drill and blast techniques. The geomechanical system of Engineers International (1984) can be an effective roadheader performance and ground support tool.

Jan 1, 1985

By V. V. Ershov

Application of computers in the study of mineral deposits pursues two main objectives: 1. obtaining reliable information on the properties of the orebody; 2. providing graphic presentation of this information for its optimal use. These problems are successfully solved if, during preparation of graphic computer software, we apply modern mathematical methods. The present paper treats the problems of using geostatistics for graphic modelling of deposits by means of graphic computers. It should be noted that in this field geostatistical methods may be used for: a) indices evaluation in the nodes of regular grid, or in given blocks, by means of kriging, for its designated purpose; b) for evaluation of accuracy of interpolation methods, traditionally used in computer graphics, and not being optimal.

Jan 1, 1986

Anhydrite-based dam constructions, which have been implemented successfully in other geological formations, were investigated with regard to their suitability in salt mines. The laboratory investigations show that anhydrite-based building materials with suitable additives bind safely in spite of the high temperatures in salt mines which normally pre-vent hydration. The dependence of the compressive strength, swelling behavior, porosity and permeability upon the choice and ratio of binding material components and additives was determined. Based on the results of these investigations, a pilot-scale experiment was carried out at the GSF Research Mine Asse (Germany) using a mixture suitable for the prevailing conditions

Jan 1, 2004

By Sergey N. Zhurin

At Gubkin Mine (Korobkovo Iron Ore Deposit, Russia) tailings are being pumped into two experimental stopes. Slurry has water content that exceeds 80%. In-situ measurements were conducted to determine pore pressure distribution in the backfilling panels. Numerical FEM modeling has been implemented to infer pore pressure distribution within filled cavities. Field observations reveal that pore pressures within neighboring stopes are slightly interrelated, because of drift connecting stopes at its bottom and single drainage system occurrence within filled caverns. Both extensive field data and numerical analysis demonstrate that water pressure on the bulkhead depends predominantly on filtration rate through bulkhead filters.

Jan 1, 2001

By J. Mastoris

The growing environmental awareness and the need for providing social service to the community, urge the primary sector companies (such as mining) to find new solutions, by adjusting their operations with the special, local conditions and meeting everyday problems in practical ways. We hereby present a real case of re-design of an open pit, closed-bench type industrial minerals (clay) excavation, for the purpose of rehabilitation and utilisation as a water reservoir. The potential use of rainfall water was studied on the basis of covering the irrigation needs and improving the living standard of the neighbouring farmers and also as a project or recreational development of the area by shaping a wetland. The experience from the project progress and the reservoir use has been positive to date and the reclamation plan seems to have the acceptance of the local community.

Jan 1, 2002