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By Jon Y. Kaneshiro, Blake D. Rothfuss, Gregory E. Korbin

A critical aspect of the planning, investigation, design, and construction of an underground excavation project is the portal. The portal is the primary access through which most if not all tunnel construction is carried out and it is the lifeline of the tunnel. Planning considerations include depth of cover, slope stability, economics of open cut versus shaft access, environmental impact, and contractor staging area. Critical aspects of planning, investigation, design, and construction of portals are considered by discussing portal design and portal failure case histories.

Jan 1, 1995

By Claude Hébert

The Grenville structural province, a 400 km-wide belt of Precambrian metamorphic rocks which crosses the province of Québec in a northeasterly direction, is the host of several wollastonite occurrences. Most of these are found in marble and calc-silicate rocks enclosed within or located near intrusive bodies. Reconnaissance and detailed mapping of such zones have helped to identify areas of interest for wollastonite exploration. The most important zone is located in the huge Lake Saint-Jean anorthosite massif in the central part of the Grenville. A recent geological mapping project has revealed the presence of wollastonite in metasedimentary faulted remnant of the roof. The main occurrence consists of diopside and wollastonite in a zone at least 3 km long and 150 m wide. Preliminary sampling suggests and average grade of 50 percent wollastonite with an aspect ratio of 151. Other wollastonite deposits occur in the western part of the Grenville, mainly north and west of Montreal, where the Morin anorthositic complex and a large syenite mass intrude the metasedimentary rocks of the Grenville Supergroup. Marble bands with up to 70 percent wollastonite occur locally at the southern margin of the complex or as an inclusion in the syenite. Significant wollastonite occurrences have recently been found in the eastern part of the Grenville. One of them is located in metamorphosed calcareous rocks which are part of the granulite facies Manicouagan metamorphic complex. A representative sample analyzed 54 percent wollastonite. Farther south, an inclusion diopside-wollastonite gneiss containing an estimated 40 percent wollastonite occurs at the margin of the Pentecôte River anorthositic complex.

Jan 1, 1995

By William Moser, B. P. Shagula

INTRODUCTION Every day mine management and mining personnel face the threat of a possible mine disaster or fire. Their ability to deal with such a situation safely and effectively depends on the level of emergency preparation developed and maintained. After conducting numerous informal evaluations or audits at different mine sites throughout West Virginia (as well as other states), the authors concluded that many mining operations are not prepared to handle a fire situation. The results of the audits indicate that while most mines are in compliance with federal and state legal regulations regarding levels of emergency equipment, water systems and training sessions, these levels - particularly in the area of fire training - are probably not sufficient to enable the mine employees to effectively combat a fire in its early stage. This paper will present the authors' recommendations for designing and maintaining an efficient mine emergency preparedness Program and an overview of the curriculum of the mine fire training Program currently being conducted. MINE EMERGENCY FXEPAREDNESS PROGRAM The Mine Emergency Preparedness Pro- gram (MEPP) is a management tool developed by the Mining Extension Service at West Virginia University and was designed to assist company personnel in effectively managing a mine emergency operation. The program goes beyond the traditional and required training of mine rescue teams by offering a complete emergency operations package. Included in MEPP are suggested approaches for training and organizing all personnel, ideas for developing plans of action concerning transportation, security and communications. The MEPP program may also be used as to assess present readiness levels. While the MEPP program is designed to address all types of emergency operations, the authors are convinced that emergencies involving mine fires are the ones of greatest concern and so are concentrating their efforts in that direction. Incidents where fires are involved seem to be increasing in frequency and are extremely costly to control if allowed to go beyond the incipient stages. With a proper emergency preparedness program in place and properly trained and equipped fire brigades, the authors feel that it is possible

Jan 1, 1992

By Michael Chender

The rapid and continuing expansion of computer and communication capability is giving birth to profound changes in the business environment. Some commentators hold that the basis of the world economy has already shifted from industry to information. Regardless of the overall implications of these changes, it is now clear that every company potentially has both access to and a need for much more information for decision making than was the case a few years ago. The importance of information to the mining industry has been underlined by the rash of unexpected economic and political developments and by the accompanying market volatility that have marked the past decade. It should be abundantly clear to even the smallest mine operator that the price for his output can be instantly affected by unexpected developments halfway across the world. Nevertheless, many mining companies still are much less sophisticated about information than they might be. For many, the historical feeling that information is an unnecessary luxury for a production-oriented business still seems to linger. On the other hand, the overwhelming volume of source material, uncertainty as to its accuracy, and the problems of finding relevant material when needed, presents stumbling blocks to viable systems of information management. Introduction When a company needs certain information, it has two basic alternatives. It can either research and develop the information in-house or pay for someone else to do it. Few mining companies have the in-house capability to assemble information needed for careful planning. On the other hand, companies often engage consultants to find information that is in fact easily accessible. All too often companies give up on procuring needed information because of the frustration of not being able to find it, and of not wanting to pay seemingly exorbitant sums for someone else to produce it. The result is poor planning. This article addresses two aspects of the information problem-finding the right sources and then accessing the particular information desired, especially as it pertains to nonferrous metal exploration and development issues. In the first section, major English-language sources that report on exploration and development (excluding primary sources of geological information, such as technical journals) are discussed.* In the second section, some available techniques for efficiently accessing this information are presented, focusing on the new MINESEARCH database system. Part One: The Information Following the News The most obvious way to follow exploration and mining developments from a distance is through regular mining media. Many active mining districts have local newspapers, usually published in the district's major towns, that give extensive coverage to miningrelated activities. For instance, to follow activities in Idaho's Coeur d'Alene silver district, one might subscribe to the Kellogg Wardner News and/or the Wallace Miner. Similarly, one might get the Sacramento Bee for news of current mining developments in north-central California. The American Metal Market, published in New York, is the daily newspaper that covers the metals industry as a whole, both in the US and abroad. Its coverage is weighted towards the refining, manufacturing, and consumption end of the business, but it frequently carries stories on mining activity, company dealings, and market outlooks. For news of major mining companies, the daily Wall Street Journal provides occasional coverage of North American companies, while the Financial Times of London serves as probably the best single source for worldwide company information. International Coverage There are three metals industry weeklies that have broad international coverage and readership. These are Metal Week, Metal Bulletin, and Mining Journal. Each has its strengths. Metals Week, a McGraw-Hill newsletter, focuses primarily on news of the metals markets, concentrating on those developments that are seen to most directly affect the price of nonferrous metals. Metals Week is strongest on North American news. Metal Bulletin, published in London, is particularly strong on

Jan 4, 1983

By S. D. Bearden

The world's barite reserve base is adequate for at least 100 years at the current consumption rate. China, India and the United States are expected to remain the leading producing countries, and the United States will continue to be the largest consumer. None of the known substitutes for barium sulfate are expected to impact existing applications. World production in 1995 was 4.41 Mt (4.86 million st), which is about 50% of capacity. Consumption is directly proportional to hydrocarbon well installation activity. Imports are expected to continue to supply more than half of the US requirements.

Jan 1, 1997

By B. Towson, R. F. Dalton, G. W. Seward

This paper reviews the successful application of oxime reagents for the solvent extraction of copper and considers the role that well focussed research initiatives can play in bringing further radical change to the metallurgical industry. Particular reference is made to the Cuprex Metal Extraction Process (CMEP), for the treatment of low grade or difficult to treat sulfide concentrates, using the reagent Acorga CLX- 50 to recover the copper and the reagent Acorga ZNX-50 for the recovery of zinc from chloride solutions. Other new extractants, currently in development, are also referenced.

Jan 1, 1994

By John W. Tieman

Coal is a term applied to vegetable matter (trees, grasses, etc.) which was subjected to heat and pressure through geologic ages. This resulted in a change in both the physical and chemical properties. Because its chemical composition is variable, geologists classify coal as a heterogeneous mineral rather than a homogeneous mineral. Peat represents the initial, unconsolidated stage in the development of coal. This coalification continues with time and the application of temperature and pressure to lignite, subbituminous, bituminous, and anthracite toward the theoretical graphite end member.

Jan 1, 1981

By L. Darkwah

The use of explosives in coal mining inevitably results in oversize, midsize and undersize (fines) products due to fragmentation. The oversize can be broken into smaller sizes by further processing. However, the undersize have a negative affect on the efficiency of a mining operation. Therefore, limiting the amount of fines can be economically crucial. This paper concerns investigations aimed at reducing fines generation in coal mining. Inherent fractures were identified as one of sources of fines generation. This paper is centered on establishing a relationship between the fracture occurrence, the explosive properties and the blast outputs, which are evaluated in terms of the fines generated.

Jan 1, 1998

By Venkata S. Vutukuri

Assuming a number of discrete leakage paths and treating the airflow through leaky duct line as a series-parallel combination of airflows along the duct and through leakage paths, exact solutions for auxiliary ventilation problems can be obtained. A computer program "SEGMENT'' has been written to solve problems using this method. However, most of the investigators have treated the duct lines with a uniformly distributed leakage and many have derived formulas assuming various boundary conditions and levels of simplification for the design of a simple auxiliary ventilation system An appraisal of accuracy of the various formulas has been conducted using the results from the program "SEGMENT' as benchmark and the formulas which give accurate results have been identified. The ranges of application for all the formulas have also been determined for 5 %error.

Jan 1, 1993

By K. N. Han, M. C. Fuerstenau, T. B. Onlin

An investigation of the removal of finely divided silica, coal, and alumina particles less than 20,µm in size has been carried out using liquid fluidized and packed beds. The bed particles used included 48x100, 100x150, and 150>200-mesh silica, corundum, and ilmenite particles. Important variables examined included surface charge, flow rate, pH and amount of bed particles. Surface charge has been identified as the most important variable in this system. Van der Waals force also assumes a very important role in the recovery of fine particles in fluidized and packed beds. In addition to interaction between large and fine particles, interaction between fine particles themselves assumes an important role in the overall recovery.

Jan 1, 1987

By D. R. Maneval

The vast coal resources of North Slope, Alaska, can be expected to attract substantial interest because the nearly flat-lying coal beds of the coastal plain are specially amenable to surface mining. Mining on a scale large enough to justify coal development in this area could have severe environmental effects. The mitigation would be uncertain because large-scale coal mining and reclamation operations have not been carried out in the arctic. The deficiency of the scientific data base is another factor that requires consideration if coal mining has to develop in accordance with the objectives of PL 95-87. The objective of this paper is to establish the inter-relationship between the problems due to permafrost and factors in reclamation of post-mining land in order to find ways to transform nature in a rational and purposeful manner and to suggest specific reclamation approaches that may be appropriate in this region.

Jan 1, 1987

By Kenneth S. Graham, S. C. Gambrell

A short term, simple roof bolt load cell which uses a birefringent (photoelastic) coating as its sensing element has been developed. The load cell is installed between the bearing plate and the nut/washer and measures the initial force after installation by the bolting machine. The load cell can be removed from the bolt and used again to measure initial force in another bolt if desired. Because temperature and humidity changes in the mine cause creep/relaxation of the coating and/or adhesive, the load cell is useful for accurately measuring force for a period of only two weeks after installation. Force in the bolt is determined by referring to a calibration curve for the load cell.

Jan 1, 1992

By A. G. Wylie

The dimensions and shape of both airborne and bulk amphibole-asbestos fibers are different from those of cleavage fragments of the amphiboles. These differences are related to the mineralogical properties unique to the habit of asbestos. These properties include the fibrillar structure, small fibrill widths and distinctive crystallographic faces of fibrills. Criteria for distinguishing amphibole cleavage fragments from amphibole-asbestos include mineralogical proper-ties observable in bulk samples and the dimensions of particles collected on air filters.

Jan 1, 1988

By Donn W. Leva

In North America, pipelines move more material than any other form of transportation. 1 Pipelines have been used principally for the transportation of liquids and gases; however, slurry pipelines have made notable gains in recent years enabling solid materials to be moved efficiently by pipelines. The obvious advantages of pipe-lines --low maintenance, low operating costs, minimal impact on the environment, greater land use, low labor intensity, safety and high operating factor --have stimulated researchers in England, West Germany, Japan, USSR and the USA during the past ten years to develop pneumatic capsule pipelines for the movement of bulk materials in large quantities. As a result of this work, pneumatic capsule pipelines are now available for the movement of dense bulk materials. Through these pneumatic capsule pipelines, material is moved in wheeled capsules which are pushed through the pipeline by flowing air. In this paper, a capsule pipeline system developed by the Georgia Institute of Technology and Tubexpress Systems, Inc. of Houston, Texas is discussed. The Tubexpress System Major Components The pipe used for a Tubexpress capsule system is standard thin wall welded steel pipe. Since pressures in the system generally do not exceed one atmosphere, the controlling design criteria for wall thickness of the pipeline is pressure from the overburden of the backfill if the line is buried or the structural requirements for supporting itself and the load if it is suspended or supported on piers. The air pumping system for Tubexpress is a combination of

Jan 1, 1977

By Niall Weatherstone

Introduction Risks & Rewards of a Mineral Reserve Life History of a Mineral Reserve Estimate Risk Assessment & Management Mineral Resource & Reserve Estimation Good Practice Mineral Resource & Reserve Reporting Conclusions

Jan 1, 2003

By S. P. Lucido, I. Iwasaki

The potential of controlling heavy metal ions in effluents from discontinued mining operations and waste rock piles has been investigated. A fresh water green alga, Cyanidium caldarium, was found to have the potential to remove Cut' from solutions while exhibiting high tolerance to acid conditions which are commonly encountered in copper-nickel mine drainage. The process has the potential for application as a low maintenance metal decontamination system. The growth requirements and copper removal characteristics of this microorganism are described.

Jan 1, 1991

By E. Topuz, M. J. McPherson, J. Banik

This paper summarizes the analyses of ventilation layouts for mines that experience both spontaneous combustion. The major focus is placed on the longwall coal mine layouts used in several countries. Each of the different layouts is modeled in the form of a ventilation network. The gob of a longwall panel is the most critical location for the occurrence of spontaneous combustion. Airflow leakage paths inside the gob are simulated by using a simplified grid-like network. Computer simulations with this model indicates that the W-system of ventilation is most effective in minimizing air leakage into the gob. Homer, the U-system of ventilation, with pressure balancing behind the face support line, is also found promising for longwall panels. The magnitude of air leakage into the gob is observed to change with the advance or retreat of bee, thus requiring appropriate balancing of pressure to maintain the leakage at a minimum.

Jan 1, 1995

By G. P. J. Schmitz, F. S. Gouws

In flotation processes the structure of the froth phase contains a wealth of information regarding the behaviour of the plant. Various structural features of the froth phase provide an indication of the froth viscosity, froth stability, mineral content, bubble size, etc., which can all in turn be related to the performance of the plant. In this paper the application of machine learning techniques to exploit information from digital images of the froth phase of industrial flotation plants is discussed. This includes both connectionist techniques to identify control decisions necessary to maintain optimal operation of the plant, as well as symbolic methods, such as induction techniques. Both approaches are used to classify froth structures based on statistical features derived from digitized images of the froth surfaces. It was found that backpropagation algorithms perform significantly better than either non-incremental or incremental induction. Backpropagation algorithms requires significant user input in order to optimally train the neural network as opposed to induction, which requires little user input. In contrast to back propagation, decision tree induction produces easily understandable decision trees which can be incorporated into a rule base or an expert system. Finally, incremental induction provides a simple means to smoothly and continuously adapt induced rules to follow changing process conditions.

Jan 1, 1996

By Joseph M. Hans

INTRODUCTION The decontamination of a uranium mill site is principally an earth moving task. The task can be completed effectively and efficiently by selecting the proper earth moving equipment and using that equipment within its particular constraints for decontamination work. A considerable backlog of experience concerning earth moving equipment selection and use was acquired during the decontamination work conducted at the former Shiprock, New Mexico, uranium mill site. This experience was acquired by trial and error while decontaminating over a wide range of depths and different types of terrain. Many different types of excavation equipment were available to the Shiprock decontamination project because the Navajo Engineering and Construction Authority (NECA) heavy equipment operator's school was doing the decontamination work and a variety of equipment was needed for training. The equipment is described and its general use for decontamination is discussed. Its on-the-job use for decontaminating the Shiprock millsite is presented. [EARTH MOVING/ANCILLARY EQUIPMENT DESCRIPTION AND DECONTAMINATION CONSTRAINTS] Tractor-Scrapers The most commonly used scraper is the bottom-dump type because it is highly mobile and can dig, carry, and spread loads. In this type a tractor is connected with a yoke to a scraper bowl (Figure 1). The bowl is essentially a rigid box that pivots around the rear axle, opening to the front. A hardened steel knife, or bit, is attached to the leading edge of the bowl. When scraping, the bit penetrates and forces the earth overlying the bit edge into the scraper bowl as the scraper moves forward. When the bowl is full, it is closed by lowering a closure or apron against the cutting bit. The load is dumped while moving, by raising the apron and forcing the load from the bowl with a crowd, or ejector. The height of the dumped load is controlled by adjusting the bit height when dumping. Scrapers of this type generally do not have enough power to scrape up loads unassisted. Loading assistance is generally provided by a crawler tractor that pushes from the rear against the scraper's push block. Some scrapers are made self-loading by adding an additional engine for the extra power needed for the load pick up. Another commonly used self-loading scraper uses a loading elevator (Figure 2). The elevator consists of two roller chains carrying crossbars. The elevator is rotated when scraping and the crossbars cut the earth above or in front of the bowl bit, forcing the load into the scraper bowl. No apron is used on elevating scrapers. The load is dumped by partially retracting the bowl floor and pushing with an ejector. Scrapers have some undesirable characteristics when used for decontamination work. One characteristic is that a clearance space exists around the apron when it is in its closed position. Part of the load (especially sandy soils) dribbles through the

Jan 1, 1981

By N. S. Tanious

This paper summarizes results from an investigation into possibly the largest coal pillar failure in the USA. The newly opened coal mine worked an 3.35 m (11 ft) seam under overburden depth that ranged from 91 to 671m (300 to 2200 ft) . The mine main entries, and the enclosed pillars, experienced a massive slow squeeze. The squeeze could not be controlled and the mains were lost. A new set of mains were driven. Entry convergence (closure) measurements were carried out behind the advancing face to monitor stability. Pillar stresses were also measured under four different depths of overburden: 229.433, 472.579 m (750,1420,1550, and 1900 ft). The strength of pillars in the new mains was calculated from the loads that triggered the failure in the old mains, using three pillar strength formulas. The stress measurements showed that the new pillars supported more load than their predicted strength, indicating that current strength formulas are inadequate under deep conditions.

Jan 1, 1992