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By H. Colijn

The trend in the coal industry for many years has been to make everything "bigger and faster" This also held true for loading and storage facilities. Where once a million ton per year mine was rare, three to five million ton per year mines are not uncommon today in the bituminous industry. This greatly increased production, made possible through mechanization, required greatly improved loading facilities just to get the coal away from the mine. Also, there is a trend toward combining production from more than one mine and cleaning it in a single preparation plant. In addition to increased loading capacity, this frequently necessitates raw coal storage and blending facilities. The development of the unit train, more than any other factor, has contributed to the widespread construction of storage and high-speed loading facilities for clean coal. In the export market, the construction of ever larger coal bulk carriers has contributed to a need for faster and larger loading facilities at ports. The present engineering and construction cost of these larger facilities make it essential that the flow and handling properties of the particular coals are fully known. These properties can be measured well in advance and the proper design criteria established. This eliminates costly surprises later on during start-up and operations. This paper will review coal and coal refuse properties, such as shear strength, cohesion, friability, and the flowability of coal and how they affect the design criteria of storage silos.

Jan 1, 1979

By S. A. Voltura

The Phelps Dodge Miami smelter has smelted copper concentrate using the ISASMELT technology since 1992. The design throughput rate was 591,000 tonnes/year and after a slow start-up, the production rate has exceeded the design after the seventh year of operation. In 2002, the smelter consumed 719,000 tonnes of copper concentrate and has the potential to hit the permitted rate of 772,000 tonnes/year. Improvements to the smelting vessel and the surrounding support processes have allowed for continuous improvement from start up until now. This presentation will outline the chronological events and the improvements completed to accomplish these improvements

Jan 1, 2004

By Deepak Malhotra, William F. Riggs, Edward C. Dowling

INTRODUCTION Mining companies are In the business of making an acceptable profit on their Investments, It became obvious in the recent recession that economic profitability/viability depends on being the lowest cost producer In order to compete on a global basis. The burden of achieving this objective falls on the mineral manager. He must strive to produce a salable product in an environmentally acceptable process while continuously Improving the profit margln.(1,2) Metal prices fluctuate on a regular basis. They directly Impact revenue and hence operating philosophy. The mineral engineer needs to develop an optimum operating strategy to meet his overall objectives, One would expect that, In the modem era of complex computer models, it would be easy to develop an economic model to maximize profits and/or cash flow. Discussions with mill managers Indicate that one mine/corporation's optimum operating strategy is not necessarily optimum for another. This paper approaches the problems from basics "Economics 101" and Illustrates the complexity of developing a universal model which can be applicable to all mines. Case examples are used to illustrate the need for better communication to avoid the basic economic fallacy “that optimization of segments leads to optimization of the whole system.” TECHNICAL MODELS Technical models are a prerequisite to the development of economic models because they provide the necessary Input data to these models, The flow of material from a mine through the sale of the finished product is shown In Figure 1. The ore Is mined and milled, and the concentrate can be stored for sale or smelted and refined In-house or at a toll facility. The finished product(s) are held In Inventory until sold either through existing contracts or in the spot market. [ ] Fairly reliable technical models have been developed for mining, milling and smelter operations. Mine plans are developed to provide a good Indication of the relationship between production and cut-off grade. It is easier to change surface mine plans than plans for underground mines. However, there are limits to maximum production that can be achieved with existing equipment. It Is possible that mine benches may not be developed to handle additional equipment, even If It was purchased to enhance production. More often than not, the cut-off grade Is lowered to Increase throughput goals.

Jan 1, 1993

By R. M. Imhof, M. J. G. Battersby, J. V. Brown

There is a plethora of former industrial sites where coal mining operations have left large slurry impoundments. These contain raw washed fines, which have previously been too expensive to process to requisite grades for commercial use. New technology has been developed for fine material processing, namely the Imhoflot pneumatic flotation G-Cell. This froth flotation technique is a highly efficient means of concentrating coal and is particularly appropriate to the nature of materials encountered in tailings ponds. The high volumetric throughput resulting from the vastly reduced residence time in the cell allows for drastically reduced equipment sizes when compared to conventional flotation cells. This means the process, when combined with innovative pre treatment and filtration equipment can be developed as a mobile plant concept. This is seen as a minimum requirement when re-treating and rehabilitating fine coal ponds.

Jan 1, 2003

By Kathleen Y. Knoebel

This paper describes a graphical mini computer system called MPASS 2 (Mine Performance Analysis/Simulation) which has been designed to conduct analysis of underground room-and-pillar mining operations using both conventional and continuous mining methods. Dynamic, graphic displays of mine face machine activities are presented on the CRT screen to provide extensive visibility into underground mining activities. MPASS 2 consists of: an interactive inputting system that graphically creates a room-and-pillar mine and describes the mine when production is initiated; a time-step simulator that produces statistical summaries of shift activities and uses CRT screen graphics for accelerated-time display of machine activities and delays; a statistical analysis subsystem for analyzing mine performance data; an industrial engineering system that permits users to enter actual machine activity statistics and replay mine operations on the CRT screen; and a data management system to store historical performance information on mine characteristics and operations. MPASS 2 operates on a Hewlett-Packard 9845B mini computer with 450 K bytes of extended memory, and is written in H-P BASIC. It has been installed at Freeman-United Coal Mining Company in West Frankfort, Illinois and at the U. S. Department of Energy Pittsburgh Mining Technology Center. Applications include production system simulation, industrial engineering analysis, production scheduling, new equipment evaluations, and training.

Jan 1, 1982

By J de Cuyper, V. M. Lovell, W. Freyberger

The recovery of apatite from the phoscorite ores occurring in the Transvaal, Republic of South Africa, involves a flotation process that is particularly difficult to characterize from a fundamental point of view. However, the reagents used, (tall oil fatty acid, nonylphenyltetraglycol ether, sodium silicate, and sodium hydroxide) can successfully bring about a separation of apatite from dolomitic calcite, which is the most troublesome gangue component. Recently, it has been demonstrated with some flotation feeds that the addition of certain polysaccharides can improve the flotation significantly. It has been shown that the metallurgy obtained is closely linked to the nature of the froth, and this, in turn, is influenced, often dramatically, by the presence or absence of certain of the reagents. The character of the froth depends less on the inherent frothing ability of these reagents than on the presence or absence of fine mineral particles in the froth, and on their surface characteristics and state of aggregation. The polyglycol ether and the polysacchar- ides have been shown to affect these properties, and it is suggested that a major function of these reagents is to modulate the properties of the fine particles in the pulp, thereby changing the character of the froth and giving rise to improved results.

Jan 1, 1976

By Daniel McConvey

Who is the Investor? -Mainly institutional, including resource funds, other mutual funds and pension funds. -Some hedge funds. -Retail investors. -How important is the reserve disclosure to these investors? -Do these investors know the difference between a reserve and a resource?

Jan 1, 2003

By Jan E. Stache

Commercial software programs are being utilized to create and maintain a mine subsidence database in conjunction with the U.S. Bureau of mines research on mine subsidence in Illinois. A three-year survey net of monitored structures in an Illinois subdivision was entered as textual information (attributes), on an existing AutoCAD drawing. These attributes can be optionally displayed on the corresponding drawing or extracted as a text file for import to a database program. The database program, dBASEIV, allows combinations of multiple database files for extensive querying capabilities. Subsurface database files can be merged with surface database files to enhance the effectiveness of surface response analyses in mine subsidence research. The geographic information system (GIS), pcARC/INFO, was chosen to integrate existing AutoCAD drawings and dBASEIV database files into a relational database with a graphical representation. The relational database allows users to update either the graphical representation or the database, with the changes being reflected automatically in its alternate format. The increased capacity, through use of a GIS, to query combinations of database files and have the results reflected graphically has significant potential for expediting mine subsidence research.

Jan 1, 1986

By J. B. Gwiazda

Introduction Thick seams constitute a considerable portion of Polish coal reserves. In producing mines and those under construction, the reserves where the height is more than 4.5 m (15 ft) total about 24v0 of all the hard coal reserves. The reserves that are under urban and industrial areas can be extracted using stowing methods for surface protection. About 50v0 of thick seam reserves can be extracted by caving methods. Thick seam mining methods Thick seams are usually extracted by multilift methods. There are some methods of thick seam mining that generally can be divided into caving and stowing methods. The stowing method is more expensive, but must be used when mining to protect surface features. The more known methods of thick seam mining include: • extraction of thick seam in ascending order with stowing; • thick seam mining in descending order with consolidated stowing; • thick seam mining with gob consolidation; • thick seam mining in descending order with roof caving; • sublevel caving thick seam mining system; and • thick seam mining system using an artificial roof. • Thick seam mining with introduction of an artificial roof The most advantageous method of thick seam mining is the method using an artificial roof. The artificial roof usually consists of wire mesh. Such wire mesh must be durable and must prevent small rock fragments from passing through. The mesh is usually made of steel properly protected against corrosion. The artificial roof is placed on the coal floor of the top slice (Fig. 1). Caving rock falls on the artificial roof and is thus separated from the coal. The next slice is extracted under the artificial roof. The producing face of the next slice must progress within 10 m (33 ft) behind the front of the first slice. As the second producing face progresses, the wire mesh moves down on the coal floor and may be used as an artificial roof for the next slice. Thus, one artificial roof allows the extraction of several consecutive slices. Application of the artificial roof allows for clean extraction and reduces coal losses. It also eliminates the hazard of spontaneous combustion. Introduction of the artificial roof has been limited due to a lack of artificial roof laying equipment. Manual laying of wire mesh is a labor-intensive operation, and it delays face progress, resulting in poor productivity. To eliminate these problems, artificial roof laying equipment was designed at the Polish Central Mining Institute. The support and the method of laying operation is covered by a patent. Artificial roof laying powered support To extract thick seams using an artificial roof; four-leg shield supports with lemniscate linkage were developed (Fig. 2). This shield is used in the first top

Jan 1, 1988

By T. Ruff, J. Steele

The lack of visibility near earthmoving equipment results in an average of five fatalities in U.S. surface mines each year. These accidents occur when a piece of equipment either strikes another vehicle or worker, or travels over the edge of an embankment. Researchers at the National Institute for Occupational Safety and Health have evaluated off-the-shelf proximity warning systems that sense obstacles near the equipment and provide an alarm to the operator. Limitations of existing systems have necessitated the development of new systems designed specifically for mining equipment, including a GPS-based proximity warning system and a computer-assisted stereovision system.

Jan 1, 2004

The deformation, failure, and filling characteristics of a caving roof in the initial and normal mining stages of a pitching oblique longwall mining area are analyzed using large-scale threedimensional physical-similitude experiments and numerical calculations to study the characteristics of roof fracture and migration in a steeply dipping seam. The results show that the roof fracture development has evident sequential and spatial characteristics. Among them, immediate roof breaking in different parts of the mining area shows difference in time and space. The failure sequence of the immediate roof in different areas changes with the mining; unique regional stability evolution characteristics are observed in the suspended immediate roof simultaneously, resulting in its significant regional stability on the goaf filling.

Jan 7, 2020

By James N. Brentz

This paper deals briefly with the problem of efficiently selecting the most cost effective haulage truck. Problems and factors are identified that effect productivity and operating cost. Despite the sophistication of computerized vehicle simulation programs, there is a wide disparity in accuracy and methodology, particularly in dealing with the various elements of cost.

Jan 1, 1984

By Alfred W. Eustes III

The first of a series on the evaluation of rock cutting tools, this paper discusses the results of full-scale laboratory drilling tests that compare the performances of several polycrystalline diamond cutter (PDC) coring bits. The tests were performed in welded tuff as part of a site characterization program. Number of cutters, size of cutters, air course design, and other parameters were evaluated as they affect penetration rate, but this paper focuses mainly on the relationships of torque vs. thrust (weight-on-bit), specific energy vs. penetration rate, and thrust vs. penetration rate. These relationships change in diagnostic ways according to bit type, bit condition, and type of welded tuff.

Jan 1, 1998

By B. G. Stone

"INTRODUCTION “Sampling is the process of taking a small portion of an article such that the consistency of the portion shall be representative of the whole” (Baxter and Parks, 1939) “An orebody is a mixture of minerals in proportions that vary in different parts of the mass. As a consequence the proportion of contained metals also varies from place to place. Therefore, a single sample taken in any particular place would not contain the same proportion of metals as does the orebody as a whole except by a highly improbable coincidence. The probable error, which would be very large if only one sample were taken, decreases with the number of samples, but it never disappears completely unless the samples are so numerous and so large that their aggregate is equal to the orebody itself, in which case the orebody would be completely used up in the process of sampling. Since carrying sampling to such an extreme would defeat its own purpose, some probable error is always present in actual cases and the practical objective is to reduce this probable error to allowable limits. This means balancing the number of samples against the desired accuracy; if there are not enough samples the result is unreliable; if there are too many, the time and expense of taking them is excessive.” (McKinstry, et al., 1948). In an actual orebody, the accuracy of sampling depends not alone on the number of samples but also on proper distribution of them throughout the orebody, for it would obviously be incorrect to take all of the samples either in a rich part or a lean part. Therefore it is important to select the places in such a way that all parts of the orebody will be represented. “For those who cultivate land which is alike arid, heavy , and barren, and in which they sow seeds, do not make so great a harvest as those who cultivate a fertile and mellow soil and sow their grain in that. And since by far the greater number of miners are unskilled rather than skilled in the art, it follows that mining is a profitable occupation to very few men, and a source of loss to many more.” (Georgius Agricola page 5 Book 1 as translated by H.C. Hoover and Lou Henry Hoover, 1950)“It is evident that mining is very profitable to those who give it care and attention”"

Jan 1, 2015

By Haydn H. Murray

Kaolin is defined and described as an industrial mineral. In addition the types of deposits -primary and secondary are defined and the genesis of kaolin from feldspars and other minerals discussed. The major deposits of the world found in the United States, Great Britain, Brazil, and Czechoslovakia are described along with many of the minor kaolin deposits. Four areas which have very large deposits of kaolin could, with technological breakthroughs to reduce viscosity significantly, become important factors in supplying the world markets which are increasing year by year.

Jan 1, 1977

By F. D. Wicks

This paper summarizes the direct operating cash costs for the Barrick Mercur open pit gold mine. A comprehensive, detailed system of cost management has been in effect for the life of the Mercur operation. This system provides the basic data for operations control and is the basis for drafting budgets as well as analyzing impact of change on operations costs. The ore body is complex geologically and metallurgically, requiring operators to pay close attention to mining and processing costs. The cost history provides data which enables analysis of changes in production levels, aging of the mine production fleet, and the impact of specific cost changes through time.

Jan 1, 1993

By J. Fuller, L. Marsden

Windborne dust from alkaline salt flats and mining-related tailings ponds is especially prone to threaten applicable ambient air quality standards. Sodium carbonate crystals, typically present, weather to an exceedingly fine, non-cohesive dust, causing air quality problems for miles downwind. Recently developed specialized polymers react with alkaline dust to form sturdy, wind-resistant crusts with good longevity. An on-going demonstration project at a major trona facility has developed techniques for cost-effective application of these polymers over large areas of soft tailings or sediments in a wide variety of situations. Recently treated areas on the order of 80 acres show effective suppression of dust.

Jan 1, 2004

By William Paul Robinson

I would like to first summarize the relevant health information relating to the workers and general populations around uranium mining as a basis for understanding the hazards associated with these operations and their available remedies. This discussion will summarize the literature on Radon and its daughters, among the most toxic uranium decay products. Second, I will discuss waste handling in the uranium industry: past, present and future, discussing exploration, mining, and milling and the volumes of water and solid and gaseous wastes which are associated with these various phases of uranium operations. This paper will also include a discussion of the various past and present materials handling technologies and their responsiveness to the concern for uranium waste isolation. I will then conclude with a summary of recent modifications in the relevant standards as applied to uranium mining and milling. Joseph Wagoner, a research epidemiologist with the U.S. Public Health Service has summarized the literature on uranium mining and its health effects in his written testimony as a commissioned witness in British Columbia Royal Commission of Inquiry into Uranium Mining in January of 1980, entitled Uranium, The U.S. Experience: A Lesson in History.1 Briefly summarizinq his report, as early as 1546, miners of uranium bearing ores in Central Europe were reported to have unusually hiqh frequencies of fatal lung disease2. As early as 1879, the real nature of pulmonary disorders among these miners was first diagnosed to be malignant neoplasia or lung cancers. Of 655 miners dying between 1875 and 1912, 40% or 276 of these Central Europe miners died of lung cancer.4 By 1939, it was reported that lung cancer mortality rate for miners in these Central European mining districts was several times (9.7 per 1000) higher than that for similar populations in Vienna, Austria (0.34 per 1000). Thus, before uranium mining began in the U.S., there was a considerable body of information linking uranium mining to lung cancers. The U.S. experience can be summarized in Table 1 also from Wagoner's B.C. Testimony.1 This table shows that through 1978, 205 respiratory cancer deaths have been observed among white underground uranium miners in the

Jan 1, 1980

By David B. McWhorter, John D. Nelson

INTRODUCTION The quantity of seepage that will be released from a tailings impoundment depends not only on the characteristics of the seepage control system, but also on the properties of the foundation soil or rock beneath the impoundment and the nature of the groundwater in the area. The interaction between various elements of the seepage control system and the influence the various characteristics of the site and impoundment have on seepage are the subject of this paper. The results of analyses are presented herein to indicate the nature and magnitude of the effect that the various factors will have on seep¬age losses. Analyses were conducted for a uranium mill tailings impoundment located in an area characteristic of many found in the western United States or Canada. A typical seepage control system consists of placement of either a clay or synthetic liner beneath the impoundment. In some cases an underdrain system may be placed on top of the liner to collect drainage from the tailings. The parameters that were varied in the analyses included those pertaining to the liner, underdrains and foundation strata. In general, it is shown that the seepage losses will vary in a complex manner depending on the interaction of the elements of the site and the seepage control system. As may be expected, the liner and underdrain systems have the most pronounced effect on controlling seepage. This paper deals with the quantity of seepage released from an impoundment However, the impact that seepage losses from an impoundment will have on the surrounding environment will depend on the rate at which contaminants will enter the groundwater and the nature of the groundwater flow itself. Consequently, when considering these results with regard to environmental impact they must be interpreted along with considerations of geochemical factors. MECHANICS OF SEEPAGE The mechanics of seepage and methods of analysis that were used will be discussed briefly herein. For a more detailed discussion the reader is referred elsewhere (McWhorter and Nelson, 1978, 1979, 1980). A general column through the impoundment was considered to be as shown in Fig. 1.

Jan 1, 1980

By Michael J. Friedel

As part of a study aimed at understanding the hydrology of in situ leach mining (ISLM), the Bureau of Mines, in cooperation with the Cyprus Casa Grande Corporation and the University of Arizona, is investigating dynamic transmissivity conditions during ISLM of a copper oxide ore deposit. Spatial and temporal variations in ore zone transmissivity during two years of ISLM operations at the Cyprus Casa Grande mine are evaluated during sixteen intervals of steady-state injection and recovery well operation. Direct inversion of an analytical hydrologic model is used to obtain estimates of transmissivity at 58 well locations during these intervals. Univariate statistical and geostatistical methods are used to describe the temporal and/or spatial relationships that exist between transmissivity and other ISLM parameters, including average well injection pressure, average sulfuric acid concentration in leach solution, and the relative configuration of injection and recovery wells. Average transmissivity during the sixteen steady-state time intervals varies between 6.00 x 10-6 m2/min. (6.46 x 10-5 ft2/min.) and 3.61 x 10-8 m2/ min. (3.89 x 10-7 ft2/min.). A trend toward decreas¬ing transmissivity is evident during two year of ISLM operations. This decreasing trend is found to correlate with a decreasing sulfuric acid concentration in injected leach solution, and suggests increasing geochemical precipitation within the deposit. Geostatistical analyses reveal a dynamic and anisotropic transmissivity structure within the target ore zone, that is dependent upon spatial and temporal changes in injection pressure and well configuration.

Jan 1, 1992