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By W. D. Diment

The concept of flying employees in and out of remote mine sites on a regular rotation basis, rather than establishing permanent support communities nearby, has gained increasing acceptance by mine operators, unions and regulatory agencies in Canada. The development of successful fly in/fly out programs and resultant compressed work schedules is dependent on meeting design requirements through comprehensive research of worker profiles to ensure the selection of suitable employees and the implementation of satisfactory working conditions. This paper presents an overview of Canadian mine industry practice with regard to the fly in/fly out mode of operation and compressed work schedules.

Jan 1, 1987

By Donald A. Brobst

The minerals barite (BaSO, -barium sulfate) and witherite (BaCO, -barium carbonate) are the chief commercial sources of the element barium and its compounds, whose many uses are nearly hidden among the technical complexities of modem industrial processes and products. Barite, the major ore mineral, is extremely vital to the petroleum industry, which in 1990 consumed about 90% of the world's production of 4.9 Mt as a major ingredient of the heavy fluid called mud that is circulated in rotary drilling of oil and gas wells. The remaining 10% of the barite production was consumed chiefly in the manufacture of barium chemicals and glass and as a pigment, filler, and extender. Barite is found throughout much of the world and is available from three major geologic types of deposits-vein and cavity-filling, residual, and bedded-in sufficient quantity at competitive prices to meet current demands. The world's demand for barite is expected to increase because of the world's need for oil and gas. Geologic circumstances are favorable for the discovery of new deposits of commercial value. Witherite, desirable as a raw material for the production of barium chemicals, is much less common and abundant than barite.

Jan 1, 1994

By William C. Cooley

Modern tunnel boring machines are subject to excessive cutter wear and bearing failures when used in hard and abrasive rock. In very hard rock, the high cost of cutter and bearing replacement, combined with slower excavation progress, make it more economical to drive tunnels by conventional drill and blast methods. The use of high pressure water jets to break rock provides a promising alternative. Experimental data indicate that the specific energy (the energy expended per unit volume of rock broken) decreases as the water jet pressure increases. Continuous jets are generally limited to pressures below 100,000 psi, whereas pulsed jets from a water cannon can attain much higher pressures. Therefore, the Federal Railroad Administration of the U. S. Department of Transportation has sponsored the design (Ref. 1 & 2) and the fabrication and testing (Ref. 3 & 4) of a water cannon to determine its effectiveness in rock disintegration at very high pressures. This paper reports the results of laboratory tests with pulsed jets against large rock samples at pressures of 125,000 to 650,000 psi and field tests against dolomitic limestone and granitic gneiss at pressures near 450,000 psi. Although initial tests were made with a small nozzle, operating at off-design conditions (Ref. 4), this paper only covers results with the full-size nozzle, including 55 laboratory test shots and 67 field test shots.

Jan 1, 1974

By A. J. Surtees, M. P. Evans

This paper discusses the development and application of sophisticated monitoring equipment used to measure the operating parameters of conveyor systems. With the radical reduction in price of computer hard- ware and software during the last decade and an associated increase in memory capacity, the concept of continuous conveyor monitor is now a reality. With this tool, the various problems normally encountered in large conveyor installations can now be avoided at an early stage. • The four main areas of application are: • Design verification • Hand-over certification • Preventative maintenance and increase of system availability Failure analysis The paper introduces the techniques used and gives examples where the service has been used.

Jan 1, 1996

By J. J. Scott, G. H. Bennett

INTRODUCTION Friction Rock Stabilizers, commonly called Split Sets,tm* have been under development since early 1973. Five years of intensive laboratory and field testing led to their introduction to the metal mines in the United States in the fall of 1976. Actual sales started in February of 1977 and, to date, over five million units have been marketed to metal mines. The present rate of useage is near 3 1/2 million units per year which is approximately 50 per cent of all roof fixtures used in the United States metal mining industry. Mr. Richard Hoppe, Senior Editor of Engineering & Mining Journal, in an article of the February, 1979, issue, entitled "Winning the Battle Against Bad Ground", said, "In hardrock mining operations in the western U.S., particularly underground uranium mines where exceedingly difficult ground is common, no roof support system has been accepted more quickly than the Split Set friction bolt invented by Dr. James J. Scott and developed by Ingersoll-Rand Co." This paper describes how Friction Rock Stabilizers function and presents technical data to show the uniqueness of the Friction Stabilizer system. SPLIT SET STABILIZERS The Split Set System is a revolutionary development in the field of ground control. The system produces an interior reinforcement to a rock mass which: *Trade Mark of Ingersoll-Rand Co.

Jan 1, 1979

By Stephen G. Hardcastle

CANMET has developed a simple yet very effective tracer gas method to test the efficiency of stench gas emergency warning systems which can easily be performed by mine personnel. This test method uses sulphur hexafluoride (SF,) as a surrogate for such stench gases as ethyl mercaptan. The test has many advantages: it is non-disruptive to production because SF, is odourless, colourless; it is safe to use as it is inert and only a small volume, insufficient to reduce oxygen levels, is necessary to dope the air with a measurable concentration; and most importantly it provides definitive results to assess the adequacy of the warning system. Specific findings of these tests have included, over doping sections of the mine and subsequent production loss due to sickness, the warning being ignored, the injection period being too short, excessive dispersion, and inadequate notification times. The simple test protocol involves releasing a known volume of the SF, under similar circumstances to those of the stench gas, and then sampling for its presence downstream. These samples are collected in air-tight syringes which are then analyzed in a laboratory with a gas chromatograph. By direct proportion, between the size of the stench and tracer gas releases, it is possible to convert the SF, concentration into equivalent stench gas concentrations profiles. From these, it is possible to define, the initial arrival time of the gas, the time it takes to reach a "target" notification concentration, whether the gas peak will exceed TWAEV, STEV and CEV exposure limits, and the duration of the peak above these levels. Since 1993, this test protocol has been employed a total of eight times on four different Canadian mine properties and the results are being used to optimize the stench gas release system with respect to volume of gas used, duration of injection, and number of injection locations.

Jan 1, 1997

By Ken Wangerud

The benefits of historic mining to this country have been many, but have come at a cost to the environment that has only begun to be understood over the past twenty years. While estimates vary, it is generally recognized that there are over 200,000 inactive and abandoned hardrock mines, with most of them located in the western U.S. Only a fraction of them are believed to be sources of metal releases with significant adverse environmental effects to the watersheds and receiving streams. State water-quality and natural resource management agencies have noted that hundreds of miles of streams are metal-impacted, and the aggregate effects of these sites within watersheds and drainage basins is poorly understood. Resources for the environmental assessment of abandoned mine land (AML) sites and watersheds have been and continue to be limited. Few hardrock mining states receive substantial reclamation funds under the (coal) Surface Mining Control and Reclamation Act. EPA Region VIII (EPA8) has an estimated 90,000 abandoned mining, milling and smelter sites, mainly in Colorado, Montana, South Dakota, Utah and Wyoming. An estimated 13,000 of the sites may have metal releases causing Clean Water Act and CERCLA non-compliance. Results of inventories by states and federal land managing agencies, indicate it is plausible that only 3,000-4,000 of these sites may be causing significant environmental degradation.

Jan 1, 1999

By Reed J. Irvine

One normally does not find sudden and dramatic changes in the investment climate, barring the unexpected outbreak of-wars or revolutions. Asia has seen a fair amount of military action and revolt during the past year, not all of it unexpected There was the fighting in Laos, which resulted in the as yet unconcluded negotiations which will probably lead to the establishment of a neutralist regime. In April of 1961 another revolution occurred in South Korea, and the elected government was replaced by a military dictatorship.. Communist guerrilla activity in South Vietnam was stepped up, and uncertainty about the future of that area increased. Relations between Pakistan and Afghanistan became more strained, and while no fighting has broken out, diplomatic relations between the two countries were broken off. India was both the victim of further incursions of her territory by communist China and the perpetrator of the forcible seizure of territory from Portugal. Indonesia has been making preparations for an armed attack on the Dutch in New Guinea.

Jan 1, 1962

By Anibal Gajardo

Clays for building bricks and roofing tiles in Chile are classified as common clays and ball clays, with deposits of sedimentary and residual origin, both Cenozoic in age. Deposits are known from north to south, through 11 of the 13 Chilean Administrative Regions, 18° to 39° South latitude, and from west to east, through three of Chile's main geomorphic features, namely the Coastal Plains, Coastal Range, and Intermediate Depression. Alluvial and lacustrine sedimentary common clay deposits are located in the northern and southern Intermediate Depression. The average chemical composition of clay deposits in I and I1 Regions, is 58 percent Si02, 16 percent A1203, and 4 percent Fe203 by weight; the primary minerals are sericite, quartz, feldspar, and albite. The average chemical composition of clays in Metropolitan, VI, and VIII Regions, is 52 percent Si02, 16 percent A1203, and 6 percent Fe203 by weight; the primary minerals are montmorillonite, quartz, and plagioclase. Residual common clay deposits occur in the Intermediate Depression and in the Coastal Range internal basins, VII, VLII, and IX Regions, and they represent surficial alteration of pumice beds and crystalline rocks. The average chemical composition of clay deposits derived from crystalline rocks is 58 percent SO2, 17 percent A1203, and 9 percent Fe203 by weight; the primary minerals are sericite, quartz, and clinochlore. Clay deposits formed from pumice beds contain 47 percent Si02, 24 percent A1203, and 10 percent Fe203 by weight; the primary minerals are kaolinite, feldspar, and cristobalite. Sedimentary ball clay deposits are located in the Coastal Plains and Coastal Range, VI, VII, VIII, and IX Regions, between 34" and 39" South latitude. The average chemical composition of the ball clay deposits is 51 percent ,902, 28 percent A1203, 5 percent Fe203 by weight; the primary minerals are kaolinite, quartz, and sericite (illite?). These clay deposits supply the Chilean building sector with over one million metric tons (mt) (1.1 million short tons [st]) of material per year. The average growth rate of clay consumption during the period 1993 through 1997 was 10 percent annually. The clays are used by both mechanized plants and handcraft facilities.

Jan 1, 2001

Selective Flocculation process development generally involves single mineral flocculation tests to identify the appropriate polymer and experimental conditions for achieving the desired selectivity. Invariably the selectivity predicted on the basis of such tests is not realized when mixed mineral tests are conducted. A systematic experimental investigation revealed that adsorption of the polymer on various substrates is critical to selecting the suitable flocculent. Simultaneously, a mathematical model was developed to predict the overall process efficiency with a given polymer. In this paper, results of these efforts to scientifically design a suitable selective flocculation process are presented.

Jan 1, 1991

By N. Dahotre, C. Blue, C. Zhao, B. Parekh, D. Tao, G. Engleman, R. Honaker

Equipment wear is one of the major concerns in screening of coal and minerals. Not only does it decrease the screen service life, it also results in inconsistent aperture sizes and deteriorates the efficiencies of downstream operations. In this research, a coating technique based on laser surface engineering (LSE) was successfully developed to increase the life span of raw coal screens. The microstructure and wear properties of the coating were investigated in this study. Enhanced wear resistance performance (up to 11-fold increase) of coated screens has been achieved in laboratory wear tests.

Jan 1, 2006

By R. Lindsay Mundell

During the past 12 years, use of longwall methods to mine coal in the United States has continually in- creased. Although these methods offer several advantages, health hazards often exist because of unique and difficult problems in the control of respirable dust. This paper discusses the results of respirable dust studies conducted on United States longwall mining operations in 1972and 1978. Current engineering control methods (ventilation, water application and use of machine cutting parameters) and administrative controls for minimizing employees' respirable dust exposures are discussed.

Jan 1, 1980

By J. W. C. Wong, S. D. Miller, J. J. Jeffery

Pre-mining identification of acid forming mine and waste materials is of concern to the mining industry because of the potential for the generation of acid mine drainage, acid rock drainage, and soil acidity problems. Accurate identification of acid forming material is essential for developing appropriate waste management strategies to reduce environmental problems related to acid generation from sulphide containing wastes. The acid-base accounting procedure, in its various forms , is commonly used for pre-mining screening of mine and mine waste materials. The procedure is generally effective when used and applied correctly but is prone to incorrect interpretation of results which can have significant financial and environmental implications. This paper examines the acid-base accounting Procedure and the possibility of misuse of this method with special emphasis on the sampling method, the sulphide forms, the acid neutralization capacity, and the interpretation of results. Data from numerous coal, base metal, and gold mining operations are used to illustrate the application of the acid-base account. The data base indicates that overall, approximately 1/3 of all waste generated by mining and mineral processing is potentially acid forming indicating the need for correct identification and management. Problems associated with simple application of 'absolute' acid-base criteria for classifying acid forming material are highlighted and the need for developing site specific or 'relative' criteria is discussed and illustrated by case study.

Jan 1, 1991

By S. Healey, P. Jean, G. Deschenes, M. Fulton

Three years ago, the New Britannia Mine started a project to improve productivity of its cyanidation plant. Results indicated that gold dissolution was strongly influenced by sulphide minerals and that the slower gold dissolution rate had a detrimental effect on overall gold recovery. The leaching strategy had to be modified to address this issue. Changes to the leaching circuit proved to be very successful. The first action was to introduce lead nitrate in the leaching circuit. The strategy of addition of lead nitrate was upgraded in three steps. An on-line free cyanide analyser was installed and the strategy of cyanide addition automated. The enhancement of the leaching kinetics have resulted: an 4% increase of gold recovery, from 87.8% in 1996 to 91.9% in 1999, which represents a reduction of 0.17 git Au in the leach residue; an average of 1330 additional extracted gold ounces per year from 1997 to 1999; a 21 % reduction in the cyanide consumption; the shut down of the cyanide destruction plant; and finally a contribution to the 27% reduction in the overall production cost per tonne of ore.($ 3 per ton). The significant increase of the throughput was instrumental in the reduction of the processing cost. In 1999, the improvement of gold recovery represented an additional gross revenue of $c""l.9 Million. The project is discussed in details in this paper.

Jan 1, 2000

By S. Peng, Yi Luo

Subsurface strata movements and deformations associated with underground longwall mining activities could cause certain influences to subsurface structures and water bodies. Methods have been developed for the prediction of final and dynamic subsurface movements and deformations induced by underground longwall mining operations in the eastern coal fields. Two new types of strata deformation, vertical and total strains, which could be useful in the field of subsidence research in assessing subsidence influences to the subsurface structures and water bodies, have been introduced. Using the subsurface subsidence prediction model, three types of subsidence influences to surface and subsurface hydrological systems have been identified. Attempts have been made to quantify the two types of subsidence influences that could cause water loss and could lower water levels in aquifers.

Jan 1, 2010

By D. A. Gulley, L. J. MacDonnell, William A. Vogely

INTRODUCTION Environmental impacts are most commonly associated with air and water pollution. Not- withstanding this fact, to many people the primary disruption caused by mineral extraction is the change in the character of the locale. That is, the environmental impact of mining includes, but is not limited to, the generation of residuals. The dramatic transformation of wilderness or rural land often creates strong reactions to mineral development. Thus, the basic issues of land use management are a useful addition to environmental discussion. In this section, we take up a discussion of federal, state, and local land use management regimes, along with a brief introduction to the potential role of economic analysis. Elsewhere in this volume, land management issues are discussed from other orientations, and the interested reader may wish to look there as well. Locatable Minerals on Federal Lands Legislation and Administration: Access to hard-rock minerals on the public lands is governed by the General Mining Law of 1872. This law declares that "valuable mineral deposits in land belonging to the United States . . . are hereby declared to be free and open to exploration and purchase . . . ." In order to initiate rights, prospectors are required to physically stake claims of specified sizes and shapes following basic procedures set by federal law which may be supplemented by the individual states. Rights to these claims are protected at the exploration stage so long as actual possession is maintained and diligent exploration activity is underway. If a valuable mineral deposit is discovered on the claim, the claimholder earns the exclusive right of possession as against private parties so long as the claim is properly maintained. To maintain this exclusive right the claimholder must per- form $100 worth of labor or improvements, known as assessment work, on each claim every year and make related annual filings with the U. S. Department of the Interior. If the existence of a valuable mineral deposit can be demonstrated, and other legal requirements are met, the claimholder may receive a patent giving full title to the claimed land, including the surface in most cases. The purchase price is either $2.50 or $5 .OO per acre. The Mining Law has remained largely un- changed by legislative amendment during its now more than 100-vear existence. However, while the law itself has not changed, its interpretation and administration have changed considerably. Written at a time of rapid western expansion of the U.S. following the Civil War, the intent of the law was to promote mineral development by inviting unrestricted prospecting and by selling the lands containing mineral deposits at a minimal charge. As federal land policy shifted from one of rapid disposal into private ownership to one of retention and management for a number of uses, mineral patenting requirements have been administered more strictly. The most critical issue concerns what must be demonstrated to establish the existence of a valuable mineral deposit. The so-called "prudent man" standard was established in the case of Castle v. Womble (19 L.D. 455 (1894)):

Jan 1, 1985

The ventilation of a mine is one of the key elements to a successful mining operation. It is, or should be, one of the primary concerns of the mining engineer at an underground mine. Too frequently, however, insufficient thought is given to future requirements. As a result, the mines suddenly find themselves with ventilation problems that cannot be corrected economically, or in short order, and have to suffer the consequences of being on the verge of having units shut down from time to time until the venlilaltion system can be improved. Insufficient ventilation in capital-intensive mining can cause production losses, the values of which far outweigh the significant costs of providing and operating an adequate ventilation plan. Many theories, and techniques in planning and control of underground ventilation systems have been developed over the years . It is the intent of this paper to point out some of the fundamental concepts, from the practical point of view, in the design and operation of a ventilation system, with special reference to underground mines using a room-and-pillar method.

Jan 1, 1986

By S. Henley

There is much in common between the requirements of open-pit mining and quarrying operations. Both involve the extraction of large volumes of material from surface excavations. The principal differences are of degree: open-pit mining of materials such as coal or gold generally involves the extraction of only small volumes of 'mineral' and large volumes of waste-they are operations with very high stripping ratios, and are made viable only because of the high unit value of the extracted mineral. In quarrying operations, the unit value of the mineral - sand, aggregate, limestone, or clay - is much lower, but stripping ration Are also lower. Thus the same techniques of geological modelling, reserve estimation, and pit planning are applicable, as is shown in two examples from the British quarrying industry. In each case, a primary requirement is the definition of production volume or tonnage. Sometimes, this need may be addressed simply by the use of a survey data processing package. However, in other cases, such as the two examples addressed in this paper, of sand and clay quarries, detailed assessment of the variation of mineral grades is a vital part of the exercise, and simple volumetric modelling cannot in itself be sufficient. In these cases, a block model approach using simple logical and numerical post-processing is also required to obtain required parameters for commercial classification of the products to be extracted. Pit designs themselves may be optimised by use of algorithms such as Lerchs-Grossmann, but the value of mineral produced can be dependent on factors other than its grade in any one part of a single pit, and the 'optimised' pit itself must be considered only a good sub-optimal. Given the right degree of healthy skepticism, and a software package with sufficient flexibility to be adapted readily to the rather different requirements of the quarrying industry, there is no reason why the quarrying industry should not benefit from the many years of investment in mining software technology.

Jan 1, 1989

By G. D. Naugle

Deep open-pit mines invariably affect the local and regional hydrologic systems. Pit dewatering, occurring during mining operations, puts an obvious hydrologic stress on these hydrologic systems. However, post-mining hydro-logic impacts resulting from the pit refilling with ground water following the cessation of mining activity can also be significant. Prediction of the rate at which the post-mining pit will fill with ground water is a critical aspect of assessing such long-term hydrologic impacts. Numerical ground-water flow modeling prov1des a method that can be used to predict the rate at which pits will fill with ground water.

Jan 1, 1992

By Pedro E. Rengifo

Splicing methods have undergone considerable developments over the last 2Oyears. Continuous conveyor belt service is dependent entirely on the strength and life of the splice to hold the two ends together. Ultimately, belting performance is dependent on the quality, efficiency, and technique of the splicer. As customers demand better belting performance and running tensions increase, the need for splices that perform as efficiently as the belting has increased also. Higher dynamic belt constructions have also dictated the need for "new"sp1icing techniques. Regardless of the belt type used or spliced, one item that is most necessary with all belt types is the quality of the workmanship and standardized splicing methods that employ all of the necessary elements required to ensure reliable field service. This paper will explore the use of Goodyear-issued internal standards for field splicing following the constraints of quality and efficiency for fabric and steel cord reinforced belting. Also included are the 10 most common mistakes made by splicers, Goodyear-issued Field Quality Assurance Standards, and check lists for end users to adhere to the manufacturers' requirements for splicing including materials and specifications for conveyor belt splicing and repairs.

Jan 1, 2004