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By Fathi Habashi

THE MOST important arsenic minerals are shown in Table 6-1. The recovery of arsenic from arsenic sulfides is treated in Chapter Four. Arsenical ores may be either leached directly, or first smelted to volatilize as much arsenic and sulfur as possible, and the resulting product, called speiss, is then leached. A speiss is mainly a complex mixture of metal arsenides, but its [Table 6-1. Arsenic minerals. Arsenides Niccolite NiS Smaltite CoAs2 Skutterudite CoAs3 Sulfarsenides Cobaltite CoAsS Enargite CuaAsS4 Arsenopyrite FeAsS Arsenic sulfides Realgar As4S4 Orpiment As2S3] composition varies widely, depending on the type of ore treated. A speiss usually contains 15-35% arsenic. Methods of leaching are describedd in the following paragraphs.

Jan 1, 1970

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. R. Parga

Bacís mining is a young enterprise in Mexico that produces a pyrite concentrate rich in gold and silver. When gold and silver are associated to sulfide minerals, pre-treament such as: roasting, pressure oxidation and bioleching, is required to decompose the sulphides and thereby expose the gold and silver particles to the cyanide solution. A novel method demonstrates that the oxidation and dissolution of gold and silver in alka-line cyanide solution can be conducted simultaneously in the same autoclave in less than 90 minutes with a recovery that exceeds 96%. Factors affecting recovery efficiency such as pH, leaching time in the reactor, temperature, particle diameter, pressure, % of NaCN and pulp density were investigated.

Jan 1, 2007

By G. W. Heunisch

The properties of Neutra-Fix® and Neutra-Ment®, two new lime substitutes for treating acid mine drainage (AMD), have been compared with lime and Allcament®, two products presently in use for AMD treatment. The two new products are basically dolomitic byproducts and produce sludges that are more compact than those from lime. Sludge settling rates are faster than lime with iron concentrations after 24 hours that comply with Environmental Protection Agency (EPA) regulations. Material utilization and optimum pH are reported.

Jan 1, 1988

By George Verley

A new and important task in assisting developing countries is the transfer of microcomputer technology applied to mineral exploration and mining. With this objective in mind, three micro- computers have been introduced in Niger and a training program has been put into place. The core of the program consists of two seminars in Niamey, Niger, after which the attendants will be able to operate a microcomputer and use a small library of application software.

Jan 1, 1987

By V. Badaker, R. J. Sweigard, C. D. Barton, J. W. Stringer, J. M. Ringe, A. D. True, D. H. Graves

Field studies have demonstrated the relationship between the growth of high-value trees on surface mined land and the physical conditions of the root growth medium. Specifically, the survival and height of hardwoods grown on less compacted material are far superior to those grown on compacted material. Furthermore, studies have demonstrated that the physical condition of the root growth medium can be characterized by dry bulk density and penetrometer resistance and that these parameters are also related to tree growth measurements. Site indices are useful for evaluating and predicting the productivity and timber yield for a specific location. A method has been proposed to estimate the site indices for various tree species on reclaimed surface mined land as a function of the physical properties of the root growth medium.

Jan 1, 2005

By L. G. Austin

Development of an equation for tumbling charge and balls plus comparison to plant data suggests that the net mill power for cylindrical semiautogenous mills can be calculated from

Jan 1, 1991

By Walter E. McCulloch

Installation of flash flotation in the copper concentrator of Freeport Indonesia in late 1986 and 1987 increased gold recovery by about 13%, while also increasing concentrator throughput. Copper recovery remained essentially the same. Flash flotation has since been included in a recently completed mill throughput expansion to 32,000 t/d (35,300 stpd) as well as in a current expansion to 52,000 t/d (57,300 stpd).

Jan 1, 1991

By S. Dessureault

Integrated information technology infrastructure is the linking of data across various applications throughout a business to gain further data-driven improvement opportunities. Decision support systems (DSS) are the various improvement opportunities that facilitate decision making for a potential optimal outcome. Integrating tera-bytes of data spread throughout a business is complex. There are tools to facilitate the development of such data-driven DSS. This paper analyzes the various tools that may facilitate the development of complex data-driven decision support systems, namely; information models, business models, data utilization model, and testing environments. A case study is presented to demonstrate how these tools facilitated the development of an automated activity-based budgeting DSS at a large-scale underground mining complex.

Jan 1, 2004

By S. R. S. Sastri, K. K. Bhattacharya, K. S. Narasimhan

Experimental results obtained on the recovery of below 0.5 x 10-3m coal fines by flotation employing geometrically similar columns of 0.056m, 0.080m, 0.100m and 0.220m diameter have been presented. The hydrodynamics of such a unit as well as its performance have been related to operating parameters to establish optimum conditions. The results have further been analysed critically in the light of the known relationship on the behaviour of similar systems to assign reasons for the critical factors established in a bid to reduce the empiricism required to be followed in the scale up of such a unit.

Jan 1, 1988

By J. Alton Burks, James P. Rider

The ability to accurately predict the sound field is essential for the estimation of probable worker noise exposure. For this reason, the U.S. Bureau of Mines is researching computer- based analytical techniques specifically geared to calculate the spatial variation of sound pressure levels within common mining environments. Initial modelling efforts describing the user interface, the simulation of energy acoustics, and the graphical representation of sound pressure levels are presented in this paper.

Jan 1, 1993

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 Gabriel Babut, Ion Matei, Roland Moraru

Several controlled recirculation systems are in operation wor1dwide. As an unconventional technique of ventilation the implementation of such a system requires particular safety conditions and a well-founded set of feasibility factors and parameters. On the other hand, many mines in Romania are facing problemms in meeting the growing ventilation demands, so that controlled air recirculation could give an answer. The present paper presents the results of the work in this field, based on a detailed theoretical approach. Parameters wich must to be taken into account were identified and analysed, numerical simulation are carried out and an experimental test-scale model is presented.

Jan 1, 1997

The conveyor housing's corroded, exposed metal- deck was cleaned and cocooned to prevent renewed corrosion, at less than the cost of replacing the structure. And the process did not require operations to shut down. That was the result for Akzo Salt at its mine under Lake Erie's Whiskey Island, just off Cleveland, OH'S north coast. The exposed metal deck was on the underside of a covered, outdoor conveyor used to load mined road salt into boats.

Jan 1, 1997

By L. B. Guo, S. S. Peng

A hybrid boundary element-finite element model was formulated to model roof-bolt reinforcement of roof strata with bedding planes. This model was used to analyze the stress distribution around a rectangular opening, with variables such as opening width-height ratio, number of bolts installed, number1 location of bedding planes, in-situ stresses, etc. The most critical areas are identified, and the number and length of roof bolt required are then determined. Two case examples are illustrated.

Jan 1, 1991

By Werner A. Dürrfeld

The Bullflex® System was introduced as a substitute for timber and debris lagging in mines and to create an in-situ early-stage interlocking effect between steel supports and the rock wall. As deplacement and/or disintegration of strata and of rock beds is to be avoided under all circumstances - following the ideas of NATM-steel support can only be loaded to the maximum when point load is avoided and ideal bedding of the rock is maintained.

Jan 1, 1981

By S. K. Kawatra, S. Bagley, T. C. Eisele

To meet federal air pollution guidelines, it is necessary to remove a considerable quantity of sulfur from many North American coals. This may be accomplished by oxidizing the sulfur to water soluble forms, followed by washing the coal. Selective oxidation of the various sulfur forms can be accomplished through the use of a variety of types of bacteria. In this paper, the various bacteria and their requirements are described, and processes using bacteria to remove coal sulfur are discussed.

Jan 1, 1988

By Donald C. Trueblood

Since the Surface Mining Control and Reclamation Act (SMCRA) was passed in 1977, coal mine reclamation has been restricted from utilizing bluff-1ike features in permanent reclamation. This restriction is based on those provisions of SMCRA which require the elimination of all highwalls. In 1987, the Wyoming Mi ni ng Association began an effort to acquire the ability for coal mines to utilize bluffs in permanent reclamation for the purpose of enhancing the post-mining land use. The regulatory reform approach being uti1ized includes formation of a work group with members from industry, government, agriculture, and environmental organizations to prepare a proposal. Advantages of this approach are discussed.

Jan 1, 1989

By Surendra K. Mishra

The principles of dewatering fine coal has been examined in terms of solid- liquid separation. It is noted that the physical and physico-chemical properties of the particle-liquid system influence the rate and degree of moisture removal. Using postulated models the roles of polymers, surfactants and other physical means as dewatering aid are discussed.

Jan 1, 1988