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By R. Hogg

The mathematical description of solids transport in mills is an important aspect of the development of comprehensive models for the analysis, simulation and control of grinding systems. The basic mechanisms of particle transport and mixing, including gravity flow, carrier fluid transport, and "diffusion", are reviewed and their relative importance in wet and dry ball mills is discussed. Specific models for transport and mixing in dry, grate-discharge and wet, overflow ball mills are described. The limitations of the models, parameter estimation problems, scale-up criteria etc. are discussed and the conditions which lead to particle size dependent transport, and hence to internal classification in the mill, are described in detail.

Jan 1, 1984

By Mungo Park, C. Baring Horwood

This paper is intended, in the light of recent investigations, to call attention to some of the essential features of good practice in sampling and mine-valuation. Mine-sampling may be divided broadly into two classes: (1) development-sampling and cornputatioll of ore-reserves; and, (2) stope-sampling and estimation of stope-values. Development-Sampling. It is with development-sampling only that this paper deals— the term development being taken to mean the opening-up of a mine by cross-cuts, drives, connections, etc., preparatory to actual extraction of the ore for milling. In development-sampling the work of the sampler and the consequent estima-

Jan 1, 1909

By Jonathon M. Hanson, John F. Schatz

A combined theoretical and laboratory test program is described with the purpose of providing a useful model of the multiple radial fracturing process. A non-quantitative conceptual model is developed as the basis for detailed mathematical modeling and test planning. The model includes borehole pressurization, flaw rupture, and gas- driven fracture propagation phases. The laboratory tests are carried out in blocks of scaled rock simulant loaded to a true three-dimension stress state and with miniature propellant/explosive charges in a wellbore as the fracturing energy source. The conceptual model, fracture initiation modeling, and laboratory test setup have been completed and are described. The remaining work is ongoing

Jan 1, 1986

By S. Finsterle, R. C. Trautz

Numerical modeling studies were performed to investigate water seepage into underground openings excavated in unsaturated fractured rock. Water seepage is an important factor affecting the performance of a nuclear waste repository, such as the one proposed at Yucca Mountain, NV. The amount of water dripping into an underground opening depends on the connectivity and permeability of the fracture network, as well as on the capillarity of individual fractures intersecting the opening. A high-resolution numerical model of an unsaturated fracture network was developed, and the appropriateness of seepage predictions using a fracture-continuum model was examined. Model calibrations to liquid-release tests performed at Yucca Mountain are also discussed.

Jan 1, 2002

By A. Marabini, J. Cases, M. Barbaro

Outlined is a review of the application of new selective chelating reagents as flotation collectors; calculation methods for the selection of chelating structures, limitation of the function of commercial chelating agents as collectors, and the synthesis of two new classes of chelating collectors with mixed aliphatic-aromatic structure for oxidized lead-zinc ores. Given are: examples of substituted mercaptobenzothiazole and aminothiophenol structures, flotation and adsorption study of an alcoxyl-mercaptobenzothiazole on cerussite, comparison of adsorption of conventional and chelating collectors, study of the influence of the aliphatic structure1 component on the collecting power of chelating type reagent and the design of chelating collectors with optimal structure.

Jan 1, 1989

By T. Lezhava

A new reactor model with rotating cathodes has been developed where various forms (dendrite, spongy) of metal depositions and their uninterrupted removal are accomplished by the realization of high current densities and low energy consumption. At the same time in contrast with the existing methods a high quality metal powder may be obtained from concentrated electrolytes without any specific organic or inorganic additives, which allows raising the intensity of the process. The reactor can be used for electrowinning of metals with low adhesive capacity (Pb, Ag, Cu, Zn, Ni, Co, etc.) and the powders. The obtained products may be utilized in general metallurgy as well as in powder metallurgy.

Jan 1, 2006

By Martin L. Smith

Sampling and subsequent geostatistical structural analysis is being carried out on the Bunker Hill Superfund site in northern Idaho's Silver Valley. This paper reports on the findings and methodology used in the initial sampling campaign which had the goal of determining an appropriate sampling grid design, spacing and protocol. Emphasis is placed on those characteristics, of mine wastes which are unique and require special consideration when applying geostatistical analysis. This study represents one of the first applications of geostatistical techniques to the problem of hazardous mining waste site characterization. Remediation of Superfund projects similar to the one described herein represents opportunity as well as liability for the mining industry.

Jan 1, 1992

By Toyohiko Hirota, Fukuo Itoh

Oil and natural gas aside, sea floor mineral resources currently being exploited in Japan are offshore sand and gravel and deep-sea manganese nodules. The mining of sand and gravel has already started. With regard to manganese nodules, the geophysical investigation and the study of the mining method are also underway. This report outlines the activity of a few Japanese firms, the Deep Ocean Minerals Association formed by some 30 private firms, Government agencies, a public corporation and two government research institutes. Researches on new exploration instruments, properties of deep-sea sediments and the mining method currently conducted by the National Research Institute for Pollution and Resources are described in detail.

Jan 1, 1976

By M. S. Klima, P. T. Luckie

Interfacing new or improved unit operations SUBMODULES with the EXECUTIVE of a macro analysis simulator usually requires modification of the input data. For example, particle processing SUBMODULES that are sufficiently general in nature to provide useful predictions require input data for rather narrow size fractions. Such data is not always available for the EXECUTIVE and must therefore be generated by the SUBMODULE. A successful interface to allow incorporation of a new SUBMODULE for comminution and one for classification in a general stream state flowsheet simulator is presented. The general nature of the SUBMODULES, as well as the logic of expanding and contracting the required data input is discussed.

Jan 1, 1983

By E. A. Metzbower

STEREOGRAPHIC projections of hcp metals depend upon the c/a ratio. Hu1 has recently published standard projections for titanium (c/a = 1.5873) of the (000l), the basal plane, the (1010), the most prominent slip plane, and the (1012), the most prominent twinning plane. Caplan et a1.2 and Hul have also published tables of angles between poles of planes, between directions, and between directions and poles of planes. From these tables standard projections and double stereograms can be constructed. However, by using the on-line CALCOMP plotter with a CDC 3800 computer, direct plots of standard stereographic projections of titanium (c/a = 1.587) have been made.

Jan 1, 1970

By R. N. Torbin

The degree to which automation, remote control and robotics have been used in the mining industry is far less compared to general industry. Reasons include the adverse working environment, the difficult work operations and the generally lower incentive for capital investments in new mining equipment. The author and his employer has been involved in the development of advanced mining and underground construction equipment. This equipment is designed to he remotely operated, to improve both productivity and worker safety. Many of these machines employ advanced electronics and robotic features. The types of machines that will be discussed include remote shaft lining and placement, remote excavation and mining operations, and automated conveyor systems.

Jan 1, 1991

By Claudia Gasparrini

Silver occurs in nature in major, minor and variable amounts in a very large variety of minerals and in several mineral species in the same ore. Because these minerals may respond differently to the same flotation or leaching agents, detailed studies to establish the correct silver mineralogy become essential for optimum recoveries in those situations where the silver is treated as a primary product. On the other hand, fine grain sizes, which often affect gold recoveries, are not generally as critical in silver metallurgy, due to the lower market price which allows for more of the element to remain In the tailings before incurring in economical losses.

Jan 1, 1984

By Fathi Habashi

THE UNIT process of adsorption involves two steps: 1) Loading of the adsorbent. 2) Recovery of metal values from the adsorbent. Charcoal is the adsorbent commonly used in extractive metallurgy. The discovery of the adsorptive power of charcoal from solutions is generally accredited to Lowitz (1785), who observed that several dissolved organic substances were precipitated on charcoal. Graham was the first to demonstrate that inorganic substances were also adsorbed on charcoal. In 1830, he reported that iodine dissolved in KI solution was adsorbed on charcoal. Also calcium ions were adsorbed from limewater, as were lead ions from lead nitrate solution. The use of charcoal in metallurgy was first applied

Jan 1, 1970

By J. P. Allen, D. A. Rice, H. L. Abercrombie

Cobalt, nickel and manganese can be recovered quickly, cleanly and selectively from cobalt-rich manganese ocean crust by leaching in dilute acid solutions in the presence of hydrogen peroxide. Common selective precipitation methods can then be used to recover these metals from the leach liquor. The leaching reaction produces only oxygen as a byproduct, and the waste residue from leaching was tested and found to be nonhazardous under existing EPA specifications. The leaching process is effective in either fresh water or seawater. This research is a part of the Bureau of Mines program to identify the mineral resources of the Exclusive Economic Zone and devise methods, for recovering their valuable components.

Jan 1, 1992

By Fathi Habashi

Precipitation of a metal from an aqueous solution of its salts by another metal is known as cementation, because the precipitated metal is usually cemented on the added metal. This phenomena was once described by the alchemists as "transmutation," when they dipped a piece of iron in a solution of copper sulfate and the iron was coated with a layer of metallic copper. The process can be predicted in terms of electrode potentials. The metal with the more positive (oxidation) potential, as given in Table 13-1 of the electromotive series, will pass into solution and displace a metal with a less positive potential.

Jan 1, 1970

By Courtney Vallejo, Rafiqul Tarefder

This study examines the effects of small scale airblast experiments on cohesive soils and the resulting ground vibrations and crater geometries. Relationships for ground vibration attenuation with soil depth and distance from the blast source were developed. The study is part of a broader research topic of understanding the vulnerability of earthen embankment dams to blast loading. Many earthen embankment dams in the United States were constructed more than fifty years ago and were not designed to withstand high-stress loading such as blast loading. These structures may be susceptible to failure and it is important to describe the response of the earthen dam during a blast event.

Jan 1, 2013

By John J. Childress, Russell L. Cook

Stringent environmental regulations, which have limited the use of sludge ponds, coupled with the economic incentive to clean more coal or to add fine coal cleaning additions to existing preparation plants have increased the use of static thickeners in preparation plants. The Lamella Gravity Settler, sometimes designated Lamella Thickener, is a shallow depth sedimentation device which has been applied in a variety of industrial process and wastewater control projects in place of the conventional raked thickeners. This paper presents the theory and design of the Lamella Thickener, as well as describing the operating results from several full scale installations in a variety of Appalachian preparation plants.

Jan 1, 1979

By Jon C. Volkwein

The industrial sand industry has been exploring new techniques to reduce dust. One company was experimenting with adding water during bagging operations to the surface of the hag, and into the product as it flowed into the bag. The Bureau of Mines, using instantaneous dust sampling instruments, measured the effectiveness of three methods of adding water. Results indicated that various types of water sprays applied in carefully controlled amounts could reduce dust up to 50% at worker locations at the bagging machine and inside a railroad boxcar. This report also discusses constraints such as product handling, customer acceptance, cold weather problems, dust collector performance, and other areas.

Jan 1, 1981

By Daniel Roy, Chris J. Preston, Ron J. Elliott

This paper discusses the use of pressure transducers in water filled boreholes in conjunction with surface mounted geophones to gather field data for in-situ dynamic rock properties determinations. A high speed collector is used to capture the data in the field. The calculated P and S wave velocities and rock density measurements are used as input into the Blastcalc program where the values of Young`s Modulus and Poissons Ratio are calculated. The rock properties information is used along with geological structural data and explosives properties in a 3-D blast modelling program to calculate predicted fragmentation distribution and other blast performance criteria based on the proposed blast design.

Jan 1, 1996

By Thomas H. Koenning

The number of spontaneous combustion incidents in the U.S. is expected to increase as the consumption of lower rank coals and the use of longwall mining becomes more prevalent. A spontaneous combustion incident holds the potential for substantial loss of life from a mine fire or explosion if not prevented or controlled at an early stage. Laboratory tests have been developed which are useful in ranking the susceptibility of various coals to spontaneous combustion. Ventilation circuits and mining methods can be designed to minimize the risk of spontaneous combustion. Early detection of spontaneous combustion is possible with the combined use of continuous monitoring, periodic gas sampling, and inspection.

Jan 1, 1989