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By Kotaro Ohga, Gota DEGUCHI, Kiyoshi HGUCHI

The situation of Japanes coal mine is in the severe enviroment, because the policy on coal mining has changed. Every year one or two coal mines will be foced to close. To continue the production of coal, we have to reduce the cost of production. Therefore, the mining by longwall method which is more than 250m was attempted at Taiheiyou Coal Mine to reduce the cost and this mining method have had successful results. To get successful results by this mining method, the controlling and prediction of gas emission from the longwall panel will be most important things. In this paper, the comparison of the predicted gas emission from the mining panel based on the measured gas content by using new device with the observed results is described.

Jan 1, 1993

By R. D. Deister

The Buick concentrator represents state-of-the-art technology in automated digital process control operation utilizing a centralized computer. The process control strategies implemented at Buick are no longer new to the industry, but the successful application of these developments is still rather unique in North America. Productivity improvements, determined to be a direct result of the process control developments, are the primary topics of this paper. Emphasis is placed on metallurgical benefits including both lead and zinc recoveries; lead concentrate grade; and reductions realized in reagent consumptions, operating costs, and personnel. A detailed description of the concentrator, along with a history of the process control development and a more in-depth discussion of the control strategies implemented at Buick can be found in the references. (The Buick flowsheet is depicted in Fig. 1).

Jan 1, 1987

By J. E. Carr

A bewildering number of continuous thickeners and clarifiers are used in mineral industries and other heavy industries. General types are: 1. Conventional Thickeners (Fig. 1). 2. Thickeners with Flocculating Feedwells (Fig. 2). 3. Solids Contactors (Fig. 2). 4. Tray Thickeners (Fig. 3). 5. Lamellas (Fig. 4). 6. Conventional Thickeners with Lamellas 7. High Flow, Fluid Bed Thickeners (Fig. 5). These units must be adapted to varied applications. They must provide operating flexibility to meet process needs. Such factors multiply the decisions which must be made prior to the selection of a thickener. The seven types of thickeners listed above, with their variations, share design concepts which limit their application and which can be used to evaluate their performance. Some of these are listed: 1. Feed velocities must be limited and/or controlled. 2. Natural or reagent flocculation is necessary. 3. Horizontal settling area is the basis for capacity. 4. Overflow velocities must be limited and/or controlled. 5. A controlled underflow is necessary. Applying these needs to the basic process concepts is thickener selection. The basic function of a thickener in the minerals industry is the separation of a thickened sludge containing fine solids from water. To this primary separation function are frequently added others to give a list as follows:

Jan 1, 1977

By Shane Yanagisawa

The Mineral Creek Diversion Project is at the Asarco Ray Mine Complex, about128 km (80 miles) east of Phoenix, Arizona. The new tunnel will intercept the waters of Mineral Creek about 2,134 m (7,000 ft) upstream from an existing tunnel. The 5.74 m(18.83 ft) hard rock TBM will break into the old tunnel about 2,162 m (7,090 ft) in from the old portal after mining 3,888 m (12,753 ft). The TBM will mine through a series of igneous and metamorphic formations including volcanic tuff, soft volcanic ash, massive diabase, fractured quartzite, and schist. The TBM will hole through into the existing 4.88 m (16 ft) dia. horseshoe tunnel where the TBM will be disassembled and removed from the tunnel.

Jan 1, 2001

By K. Zabrusky

"Wireframe construction is an integral part of resource estimation. Wireframes control domaining of samples and data for geostatistical analysis and grade estimation. They may also provide 3D representations of lithology and grade domains. Thus, the way in which a wireframe is constructed has implications throughout the resource estimation process. Proper construction technique and understanding of wireframing processes should be a high priority in a model workflow. Herein is presented an overview of two main categories of wireframes: implicit and explicit. Construction differences between these two types are highlighted. Factors affecting the choice between the two wireframe types will be discussed, including data quantity, data distribution, and sampling technique. Deposit geometry also plays an important part in wireframe construction. The role of geologic knowledge, cross section orientation, and deposit type in regards to wireframe construction will be discussed. The effect of wireframe type on resource estimation will be examined. Finally, best practices for creating meaningful solids that contribute to a reasonable grade estimation are outlined. INTRODUCTION Wireframes are essential to many types of resource estimations. They provide a way to delineate a deposit into various domains. Domaining can be done by lithologic or geologic units, structures or structural zones, or by grade. Domaining is important for geostatistical analysis and grade estimation of a deposit. The purpose of domaining is to analyze and estimate like data with like. Grade distribution patterns may vary by lithology or by proximity to or existence within structural zones. Properly constructed wireframes are therefore a fundamental necessity to a properly executed geostatistical analysis and resource estimation model. The choices made in construction of wireframes have a trickle-down effect on the entire model and should be made according to best practices for the deposit type at hand.TYPES OF WIREFRAMES Explicit The term “explicit wireframe” is used in this paper to indicate wireframes that are constructed by the modeler. This usually involves the modeler drawing the wireframes “by hand”, e.g. still utilizing some sort of computer aided drawing software, but with the modeler making all decisions about the size, shape, and positon of the wireframe. These wireframes are drawn based on some type of key variable that the modeler determines is important to their system. Often, this key variable may be a lithologic unit that controls mineralization, an observable structural zone, or a grade cutoff. Explicit wireframes are generally constructed as a series of shapes drawn on 2D planes or cross sections that are then connected into a 3D shape. Figure 1 shows an example of an explicit wireframe that was drawn based on a grade cutoff on 2D sections (Figure 1a), then joined into a 3D shape (Figure 1b)."

Jan 1, 2015

Surface contamination of minerals during fine grinding may occur due to coating of one material on the other. This can alter the surface chemical properties and adversely affect the separation of minerals by physico-chemical processes. In dolomite-silica system, selectivity was completely lost (compared to a synthetic mixture) after wet grinding of the minerals in spite of using a dispersant. Adsorption and surface characterization studies were conducted on silica particles separated after grinding with dolomite. SEM-EDAX analysis indicated the presence of dolomite on silica particles, which could cause the loss of selectivity.

Jan 1, 1993

By John E. Riddell

This review is based on a questionnaire sent out to 24 Canadian exploration companies, known to be active in the mineral exploration field, concerning their practice in the use of applied geochemical techniques in Precambrian terrains. Of the companies questioned, 16 returned completed questionnaires and of these, ten companies stated that they had some experience in this type of work. Of the companies who did not answer or return the questionnaire in time I know that at least three have been quite heavily engaged in applied geochemical work in the glaciated Precambrian areas. I also know that these three companies have been reasonably successful in their ventures, so I feel the following figures and opinions are, if anything, on the pessimistic side. Before continuing with the paper I would like to express my personal thanks to the Chief Geologists, Geologists and Exploration Managers of the various companies who cooperated in making this review possible by answering the questionnaires and making available summaries of their work in the glaciated terrains. Of the companies who stated that they had no experience in geochemical prospecting in glaciated Precambrian areas it is interesting to note that only two have reported that they do not use applied geochemistry at all. Two companies have reported that they make use of applied geochemistry in New Brunswick in areas of-light glaciation. Their opinion is that it is a useful aid to other techniques in evaluating mineralized areas.

Jan 1, 1960

By C. S. Boland

The Copper Range Company's mining properties are located in the Upper Penisula of Michigan. (Fig.). Early work indicated the presence of copper ore in a bedded deposit, confined to the base of the Upper Keweenawan Nonesuch shale, and exploitation of this deposit on a portion of the Company's property was undertaken by White Pine Copper Company. Diamond drilling of the White Pine orebody indicated that a major fault pattern terminated the values to the South-west. Further drilling Southwest of the fault zone proved a downward displacement of the ore bearing horizon some 1,500 feet and a lateral displacement of approximately 4,000 feet; and in this area an ore deposit was outlined in a large asymmetrical syncline locally plunging to the South-west. (Figs. 2 and 3)

Jan 1, 1962

By A. B. Cortes

This research work discusses the development of a two-dimensional model that represents the flow that occurs in the inlet section of hydrocyclones. The governing equations are the two-dimensional, unsteady, incompressible Navier-Stokes equations in cylindrical polar coordinates with primitive variable formulations. In this approach, no assumptions have been made other than independence in the axial direction. The full two-dimensional Navier-Stokes equation in the r-a plane is used. The commonly used simplifying assumption of axisymmetry is not used. A numerical technique based on a newly developed spectral-difference method is used to solve the equations. The spectral-difference method is a multi-domain, and multi-dimensional extension of the Jacobi polynomial collocation technique. The computational grid for the inlet section is composed of 25 sub-domains which result from five partitions in the angular direction and five partitions in the radial direction. Several test cases are used to validate the appropriateness of the numerical model.

Jan 1, 1995

By W. G. Kegel

Coal mining today is confronted with numerous problems, all of which affect in some way the ability of the operator to produce profitably. The major endeavor, therefore, is a quest for cost lowering techniques. Complete belt haulage from shuttle car to river barge appeared to be a step in such a direction. A deep look into all aspects proved this to be more involved than just the installation of such a belt line. With this paper, we will attempt to present to you the problems and requirements of design and installation of an all-belt haulage system, believed to be the longest underground belt installation in the world at this time. The first and most important item is the justification of an all-belt haulage system. The following is a brief history of the coal property and the facts affecting our decision.

Jan 1, 1964

By F. C. Bond

History The breaking and shaping of rock was one of man's earliest occupations. In the Paleolithic Age long before the dawn of history, arrow¬smiths and the makers of stone axes, hammers, knives, scrapers, spears, and borers were highly respected members of society. In early historical times stones for building blocks, roads, and city walls were shaped by slaves and convicts, who also did most of the mining. However, great artists erected beautiful stone sculptures, while gifted architects planned imposing temples and monuments. Until well into the 19th century nearly all rock was broken laboriously by hand. The small rock required by John MacAdam for his macadamized roads in England in the 1820s was produced by women and boys seated alongside the roadside with hand hammers and legs wrapped with rags. Eli Whitney Blake, a nephew of the Eli Whitney who invented the cotton gin, developed the first successful jaw crusher before 1870. The gyratory conical crusher soon followed. Comparative tests established its large capacity advantage over the jaw crusher, as well as its greater cost for a given feed size. Both types have been in use for more than 100 years. Crushing rolls appeared before 1900. Thomas A. Edison made very large diameter rolls which were excessively long; they failed because of shaft deflection. Various types of disk crushers and edge runner rolls appeared about this time. The older methods of reducing rock were adaptations of other processes. The stamp battery of dropping weights effected crushing by simulating heavy hammer blows; the much earlier arrastre, in which heavy stones were dragged in a circular path over the ore by animal power, came from the prehistoric method of grinding grain between two rubbing stones, while the jaw crusher was adapted from simple squeezing devices. But the tumbling grinding mill was not just an adaptation; it was an invention, because it required thinking on a somewhat higher order-there was no prototype. Its nearest antecedents were probably the small closed tumbling drums used in England more than a century ago for cleaning and polishing small iron castings. The date of the first tumbling mill actually used to grind rock is unknown, but it was later than the American Civil War (1861¬1865). It was almost certainly a closed or batch mill in which rock was placed and rotated until it reached the desired particle size. It could have been operated either wet or dry. The first published refer¬ence to such a batch mill was one introduced by Alsing in England (1870) for the grinding of calcined flints for pottery work.21 There are several rather indefinite reports of grinding mills in the early 1890s, including an overflow ball mill in the Helena and Livingstone reduction plant in Montana which may have been the first of its kind. 11 Many of the first mills, which were called tube mills, used hard rock both as grinding media and as mill lining. The rock used was preferably stone from the Normandy and Danish beaches, when it could be imported. This remarkable siliceous stone was already widely used for grist mills throughout America, and its resistance to wear was greatly respected. The decade of the 1890s saw the development of tumbling mills with continuous feed and discharge and their extension into different industrial uses. By 1895 some experience had been accumulated. Iron grinding balls were being tested and the proper speed of rotation was being determined. The Clark Patent tube mill was featured in an E. P. Allis bulletin of 1890, which may have been the first published description of a tube mill. More than 1,000 Gates tube mills had been built by Allis-Chalmers before 1913. Many of these were used in gold mining, espe¬cially in South Africa. The 5 x 22-ft size was particularly favored for grinding portland cement; the use of tumbling mills in the manufac¬ture of cement began about 1900. A great deal of attention was paid to the mill lining. Metal was then relatively expensive, and the general approach was to trap some of the rock grinding media into mill lining pockets. This rock would then absorb the wear and protect the metal lining. In the first ten years of the 20th century there were several different types of pocketed liners, with different manufacturers advancing the superior claims of their patented arrangements. The Osborne liner, developed in South Africa, was probably the most successful. 21 Another item which attracted much attention was size classifica¬tion within the mill and in ancillary equipment attached to the mill and rotating with it. The Krupp type, with interior screens protected inside the mill lining, was developed quite early in Germany, possibly before 1890. The Dorr reciprocating rake classifier (1907) had not yet been invented, and many strange and impractical screening and classifying devices were proposed. In these unsatisfactory machines the two separate processes of size reduction and classification were combined into one operation. It was many years before recognition came that a machine is most efficient when it is designed for one specific purpose. There was much industrial wastage before the opera¬tions of grinding and classification were finally separated. After 1900 the grinding of portland cement raw material and of cement clinker required large numbers of tumbling mills. Most of the raw material was then ground dry. This was also the heyday of gold mining. The old stamp mills that were used in great numbers for grinding gold ore did not grind sufficiently fine to liberate all of the gold, and the new tube mills were installed following the stamps. After 1910 larger diameter tum¬bling mills with larger grinding media were developed. These could receive the finely crushed ore directly, and the inefficient stamp batter¬ies were gradually eliminated. The Rand in South Africa was the greatest gold producer, treating immense quantities of rather low-grade but consistently free milling gold ore. The first tumbling mills, or tube mills, went into operation there in 1904. They were so successful that within a few years no new stamp batteries were installed in the district, even though old ones continued to pound away until after 1950.3 The early tube mills on the Rand all employed Normandy or Danish pebbles, which had to be imported at considerable expense. Their reported wear was as low as 4 lb per ton ground. 4 Many of the mills were lined with the same tough Danish stone cemented into place, while others used the pocketed steel Osborne liner. It was in 1907 on the Rand that an important test was made using hard native ore for grinding media in place of the expensive imported pebbles. 3 This ore, called banket, did not wear as well as the renowned Danish pebbles, but the cost per ton of grinding was definitely reduced. Many of the tube mills on the Rand were soon grinding with native ore. This was the beginning of the development now called autogenous grinding, in which the ore grinds itself. This is treated under a separate heading. See Subsection 3C, Chapter 4. Gold mining was important in America also, and its grinding history follows that of the Rand. Danish pebbles were replaced by native ore in Santa Gertrudis, Mexico, in 1913, 4 and in Consolidated Gold Fields, Nevada, in 1914. 5 Other properties followed suit. However, it gradually became apparent that the capacity of a given mill could be almost doubled if rock grinding media were re¬placed by cast iron or steel grinding balls. In order to increase plant grinding capacity many rock media mills were converted to iron grind¬ing media in the second decade of the present century. In some mills the motor size was doubled; other mills were cut in two and another motor was provided for the second half. Grinding mills began to assume a more modern appearance. Crushing rolls were formerly much used following crushing in jaw or gyratory crushers and preceding grinding in ball mills. How¬ever, the roll surfaces wore rapidly, and skilled maintenance was required to obtain even wear. Rod mills could take feed of the same crusher product size and reduce it finer. The first rod mill was con¬structed by Mine and Smelter Supply Co. and was tested in Canada

Jan 1, 1985

By Louis D. Murino

Compared to coal or many metals industries, talc must be considered a small, specialty market catering to niches and dependent primarily on the physical attributes of the mined and processed mineral rather than the chemical attributes with copper, lead or uranium concentrate, the primary objective is the percent metal that ultimately is refined by the smelter, as opposed to the brightness, particle size distribution, trace impurities or morphology. The latter constitute the important determinants of where, how and why talc and similar industrial minerals are used. This paper addresses the talc market-place: where it is, how much of a market there is, who the producers are, available capacity, market growth, and marketing techniques.

Jan 1, 1984

By William P. Walsh

In December 1983 the author undertook an investigation in east Texas which was organized to learn the feasibility of applying geophysical techniques over shallow lignite deposits. The work embraced experimental high resolution seismic reflection and offset Wenner resisitivity sounds over three 1/4 to 1/2 mile test sections. This site also was sponsored by Woodward-Clyde Consultants (WCC) and a consortium headed by North American Coal Corporation. The principal objective of this investigation was to learn whether the aforementioned geophysical techniques could be applied over shallow lignite deposits (i.e. located at approximately 100' to 300' in depth) and consequently provide structural and stratigraphic information useful for resource and reserve characterization. A secondary objective was to determine if these same techniques could disclose the nature of the overburden and the distribution of ground water therein.

Jan 1, 1986

By A. D. Paananen

With the demand for higher grade feed by the American steel industry and the depletion of the direct shipping ores from the Marquette Iron Range and elsewhere, there was a need to develop the low-grade orebodies. The large reserve of fine grained oxidized iron-formation at the Tilden Mine has been the object of research and development efforts to concentrate the iron oxides as far back as 1949. Preceding the present mining-concentration-pelletizing complex, about 6,500,000 long tons of direct shipping siliceous ore were shipped from the Tilden Mine. Following development of the concentrating and pelletizing flowsheets, engineering and construction was initiated to develop the mine and construct concentrating and pelletizing facilities to produce 4,000,000 LTPY of pellets from this low grade crude ore. Operations started in late 1974 with Algoma Steel, J&L Steel Corp., The Cleveland-Cliffs Iron Company, The Steel Company of Canada, Ltd., Wheeling-Pittsburgh Steel Corp., and Sharon Steel Corp. as participants. Cleveland-Cliffs operates and manages the operation. Due to the non-magnetic nature of the ore and the fine grinding required to liberate the iron oxide minerals, this crude ore was not amenable to concentration by conventional methods. The iron oxides of the Tilden orebody have a grain size of less than 25 microns and recovery of the finer, well-liberated iron oxides is essential. Conventional methods of des liming employing cyclones or thickeners were not feasible because of the excessive loss of iron oxides in the finer fractions.

Jan 1, 1978

The role of ZnSO4 in activation of sphalerite (ZnS) and deactivation of lead-activated sphalerite has been investigated. Adsorption of metallic ions at the solid-solution interface, electrokinetic results for sphalerite under different chemical conditions, and thermodynamic calculations were used to elucidate the mechanisms involved. It is shown that flotation response of sphalerite in absence of activators is rather weak and that adsorption of ethyl xanthate on the mineral mainly electrostatic in nature. Zinc sulfate is found to activate the mineral but only in a narrow acidic pH range. This is attributed to the increase of zeta potential as well as the possible increase in amount of negatively charged bulk precipitated zinc xanthate. Lead ions activate sphalerite in a wide pH range and the lead activated mineral assumes a flotation behavior similar to that of galena (PbS). However, addition of ZnSO4 depresses the lead-activated sphalerite by replacing lead ions at the mineral/solution interface.

Jan 1, 1999

By G. E. Slagel

On August 3, 1987, a hearing was held by the House Subcommittee on Energy and the Environment to commemorate the tenth anniversary of the Surface Mining Control and Reclamation Act (SMCRA). Four panels of environmental/citizen group representatives went before the Subcommittee to report on the state of affairs (from their perspective) of the coal industry and the Office of Surface Mining, Reclamation and Enforcement (OSMRE) As expected, these groups had little positive news to report and continued to focus on glaring deficiencies within the surface mining program. They indicated that gross abuse of SMCRA has continued over the past ten years and the states have performed poorly. Congressman Udall's opening comments perhaps best characterized the mood of the group with his statement that "The Act has not accomplished what I or the people of the coalfields had hoped." and " ? a segment of the coal industry has continued in its bitter and implacable opposition to the most basic of environmental controls."

Jan 1, 1988

By Sheldon P. Wimpfen

Under the Wilderness Act of 1964 and the accompanying House Conference Report, the Geological Survey and Bureau of Mines are charged with the responsibility of making recurring mineral studies of wilderness and wilderness candidate areas in national forests within and proposed for the National Wilderness Preservation System. The Wilderness Act, a major shift from the multiple-use concept of national forests, identified for the first time the value of mineral resource information in decisions for single-use designation of public lands. This concept was further realized when the Secretary of the Interior in May 1974 recommended that mineral studies be made prior to wilderness recommendations for five large Interior-managed game ranges and the Glacier Bay National Monument aggregating 7.8 million acres. Presently, our studies have been completed on 126 wilderness and proposed wilderness areas totaling 15.4 million acres in the national forests. In 1973, 1 year in advance of the act's 10-year review deadline, we completed the 34 primitive areas, originally the only potential additions considered by the 1964 Act.

Jan 1, 1975

By L. Hales

Neural networks are a generalized, multivariable non-linear modeling technique that can be used to model mineral processing operations. Neural networks will be described as will their use in modeling column flotation. Optimization of column flotation will be explored and discussed by using the neural network column models.

Jan 1, 1996

By T. W. Lloyd

Accurately predicting coal seam discontinuities is an important part of modern underground coal mining. Conventional methods of coal exploration sometimes fail to identify rapid variations that may seriously impact mining and quality. Radio Imaging Method (RIM), a geophysical approach to mapping longwall panels, has been developed where electromagnetic signals are transmitted and received though the coal block. The amount of signal loss for a given distance, when compared to the coal seam characteristics, identifies anomalous areas. A comparison of RIM predictions with actual geologic conditions encountered during longwall mining demonstrates the accuracy and usefulness of the data.

Jan 1, 1986

By John A. Sievert

Sedimentary deposits contain an appreciable portion of the world's supply of uranium. Predictions of nuclear fuel usage in the United States indicate that these reserves will have to be tapped if the domestic industry is to be the major supplier of fuels for the nuclear reactors. Techniques developed within the petroleum industry are a base on which to build economically attractive fluid mining processes for the recovery of these uranium values. The problems central to the success of such mining processes are the containment, control, and recovery of a narrow band of pregnant leach solution as it progresses from the point of injection to the point of production Given sufficient incentive, suitable solutions to these problems can be found

Jan 1, 1970