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By J. A. Herbst, Z. Rogovin

In order to develop more accurate procedures for scale-up and design of semi-autogenous grinding mills through detailed mathematical models, a better understanding of the charge motion and rocklball segregation is needed. To achieve this a 0.61 m (2.0 ft) diam by 0.305m (1 .0ft) length plexiglas mill was constructed as a scale model of a commercial SAG mill. Rock motion in the rotating mill was simulated using various sizes of ceramic balls. Quantitative measurements of dynamic angle of repose, water and slurry motion, holdup and size segregation of the charge were taken. In addition, a video presentation (available to the public) was prepared to elucidate charge and water motion at various mill speeds, charge volumes, rocksize distribution, and flow rates.

Jan 1, 1990

By Richard Giffen, Michael Trabold, Pablo Lemus

"As part of the new 2nd Ave Subway Project, an existing tunnel constructed in the 1970’s will be connected to the new subway and used as new running tunnels. The existing tunnel had to be modified to comply with newer structural and fire life safety codes and to be connected to the new cut and cover station at 96th St. This paper will discuss the complexities of tying an existing tunnel constructed over 40 years ago into the new station and allowing for movements due to the unloading of the existing tunnel and the differential settlement of the two structures during both the construction and permanent condition. Topics that will be discussed include structural analysis, ground improvement techniques, selection of support of excavation walls, working in contaminated soil and instrumentation and monitoring of the structures. It will also cover retrofitting the tunnel to comply with updated Fire/Life/Safety requirements. PROJECT OVERVIEW The Second Avenue Subway (SAS) will be the first major expansion of New York’s subway system in over 50 years. To be constructed in four phases, it will run from 125th St. in Harlem to Hanover Square in the Financial District (see Figure 1). For most of its length, the alignment is directly under the Second Avenue roadway."

Jan 1, 2016

By David R. Maneval

The mining of coal in Alaska receives special treatment in the Surface Mining and Reclamation Act passed by the U.S. Congress in 1977 (PL95-87). Section 708 of the Act required that the National Academy of Sciences (NAS) perform a study of "Surface Coal Mining Conditions in the State of Alaska, In Order to Determine Which, If Any, of the Provisions of the Act Should be Modified with respect to Surface Coal Mining Operations in Alaska'. The special committee on Alaskan Coal Mining and Reclamation of NAS completed their study in 1980 and prepared their report (NAS, 1980). At this time, the Secretary of the Interior and the Congress have taken no special action with regard to either special regulations geared specifically to Alaska or to submitting special draft legislation to the Congress requesting amendment of PL95-87. The Alaska Department of Natural Resources (DNR) has drafted legislation which was submitted to and passed by the 1982 session of the State Legislature. The State regulatory agency has also drafted the requisite regulations necessitated by the amendments to the State's Basic Coal Mining Act. It is expected that by mid 1983 DNR will have applied for "primacy" to the office of Surface Mining, U.S. Department of the Interior (OSM). They will be submitting the amended State Law, the revised State Regulations and an operational plan as called for by OSM regulations. The presumption is that primacy will be granted to the State of Alaska under PL95-87. The Usibelli Coal Mine continues to be the only operational commercial mine for coal in the State of Alaska. It produced 7.26 x 10 kg (8 x 10 " T) of coal during 1981. The current mine was started in 1920 by Captain Lathrop, an early developer and pioneer in Alaska. It was continued by Emil Usibelli and was taken over after the death of E. Usibelli (in the 1964 earthquake) by his son Joseph Usibelli who is the current President of, the firm3 Their latest improvement is a 27.5 m (36 yd. )Bucyrus-Erie Dragline which handles most of the overburden removal. The coal is removed by a loader-truck combination. They are currently starting up the use of a unit train loading facility which handles forty cars every two hours. This loading system was a development necessitated by the Sun Eel Export contract. The Alaskan Railroad was a major cooperator in the development of the first unit train loading facility in Alaska.

Jan 1, 1982

By Richard L. Gordon

Coal supply analysis has since about 1973 become a major activity of many scholars and consulting firms. The present paper is an effort to explain in as nontechnical fashion as possible the state of the art and what implications, if any, the research has for those actually engaged in producing coal or regulating the industry. l The discussion stresses the coal supply side of the models and makes limited comments about other elements in the analysis. To orient the appraisal, it is desirable to recall the features of coal supply that an adequate model should capture. The first considerations are the locational aspects of the industry. Transportation costs can, in some cases, exceed the production costs of coal, and thus any adequate model must incorporate a treatment of the economics of transporting coal from one location to another. A second major issue is that of the heterogeneity of coal; models should treat as well as possible such key differences among coals as their Btu and sulfur content. Third, we recognize that, with given technology and labor, capital, and supply costs, an expansion of the supply of a given type of coal in a specific region will occur only if prices rise. This is the familiar proposition of textbook economics that supply is an increasing function of price. Finally, over time, changes in technology, input cost, and depletion interact to cause changes in the price of given amounts of coal. Economics represents the net effect of this process by a shift over time in the supply curve. During the 1950s and 1960s, the trend was to reduce the production costs of a given output; subsequently costs rose sharply.

Jan 1, 1977

By Joseph B. Gillenwater

Miss Gertrude Carey lived next to us in Martinsburg, West Virginia for several years. She was a retired school teacher. She was also a cousin to Messers Dan and Joe Baker who owned and operated Standard Lime and Stone Company, a predecessor of Martin Marietta Corporation. She-was well acquainted with the Baker family and their history. Here is one of the legends she told my wife, Jean, and me. The Bakers were originally Tanners. They had a tannery near Frederick, Maryland. There were several boys in the family and when they were grown each man had specified responsibilities. Will Baker was assigned the duty of locating, buying, and transporting tanbark and lime. As he traveled through Maryland, Virginia, Pennsylvania, and West Virginia to locate and buy tanbark, he also talked the farmers out of some pieces of lime, which the farmers had produced in holes dug and filled with layers of limestone and wood. Will Baker took the lime and soaked a piece of hide in the milk of lime. If the lime did not spot the hide, Will Baker would get the farmer to burn some lime for him, and further tests would be made. If these tests were good - the Bakers bought the land. They eventually discovered that the limestone that would make lime that wouldn't spot the hide would also be suitable for producing steel. They began producing lime just outside Harpers Ferry, West Virginia in pots and upright kilns. That stone too small for the kilns was just perfect for railroad ballast. Now you know how "Baltimore Blue Bloods" got together!!

Jan 1, 1979

By Peri Mehling, Allister Brown

Environmental regulations concerning the processing of gold ores and the treatment and disposal of spent process solutions range from rigid standards in some locations to site specific options in several other jurisdictions. This paper examines the regulations and policies in two North American jurisdictions. Emphasis will be placed on the mill process and waste stream treatment and disposal, and implications for environmental impacts. Case examples of mine licence requirements will be discussed, with brief descriptions of individual treatment and disposal systems. Policies and environ- mental regulations within each jurisdiction will be examined in terms of potential environmental protection.

Jan 1, 1987

By William L. Husk

Stockpiles have always been a necessary part of coal mining except, perhaps, when a person was mining only for the needs of his family from a seam on his home place or coal mined for the use of a small hamlet and carried to each man's house as it was mined. Then it may have been stockpiled at each man's place for several days or on the village common. Mining with this limited production required waste stockpiling. Stockpiling of the products of coal mining, both coal and waste material, has always been a necessity. Very little coal has ever been moved directly or immediately from the working face to the point of consumption and burned. It has always been expedient to stockpile the coal some- where and store the waste.

Jan 1, 1981

By Omar A. Muhtadi

8.1 INTRODUCTION Several methods currently exist by which gold may be recovered from a pregnant leach liquor. Two of these methods are discussed in this chapter, the Merrill-Crowe (zinc cementation) process and the carbon adsorption process. These two methods represent the most frequently used techniques for gold extraction and are, -in fact, used almost exclusively in U.S. heap leaching operations. Because of the efficiency and ease of use of these two methods, it is extremely likely they will continue to be quite prevalent within the gold mining industry in years to come. The remainder of this chapter includes information on the history of the two processes, descriptions of the actual processes, criteria to consider in selecting a recovery process, and commercial design and construction considerations for both of the gold recovery methods. As with other chapters in this book, some fairly technical information is presented for the benefit of those readers needing a greater level of detail. However, the overall intent of the chapter is to provide an overview of the processes likely to be used in gold extraction, thus giving the reader a firm basis for more technical research into the topic, should this be needed. 8.1.1 History of Zinc Cementation During the late 18901s, zinc cementation was introduced for the precipitation of gold and silver from cyanide solutions. This occurred at about the same time as the introduction of the cyanidation process, the history of which is recapped in Chapter 1. The initial cementation process involved introduction of a gold-bearing cyanide solution onto a bed of zinc shavings. It proved to be quite inefficient because the reaction rate was very slow. The zinc quickly became "passive", inhibiting further gold deposition. Shortly after this first introduction, zinc precipitation was improved by adding a lead salt (usually lead nitrate) to the zinc. This allowed a zinc-lead couple to form on the surface of the shavings, eliminating passivation of zinc surfaces and thereby allowing continued deposition of gold. Further improvements were shortly forthcoming. The first of these involved the use of zinc dust rather than zinc shavings. This provided a much

Jan 1, 1988

By John H. Bassarear

Large scale equipment can reduce both capital and operating costs for concentrators. Large semiautogenous mills can be effectively utilized in big mills but they must be kept fully loaded to take advantage of their great potential. With varying hardness ores, controlling throughput is difficult and careful design must take this into consideration. A variable speed drive on large primary semi- autogenous mills can overcome this problem to a considerable degree. This paper provides a base case using standard accepted technology of two wound rotor single speed 4,476 kW (6,000 hp) motors to drive the primary SAG mills of a hypothetical 36,364 mtpd (40,000 stpd) typical porphyry copper mill. One other fixed speed drive will be described and five variable speed drive configurations will be reviewed. Capital costs for the entire grinding circuit, from crusher product to flotation feed, were developed for the base case and each of the alternatives. A technical evaluation comparing the advantages and disadvantages of each drive is presented.

Jan 1, 1985

By Robert J. Guardia, James Rustvold, Robert A. Robinson, Christopher A. Robertson

In 1999, the Bonneville Power Administration (BPA) replaced approximately 730 m(2,400 ft) of damaged 42- and 36-inch concrete pipe by microtunneling Permalock pipe through sand and partly below groundwater. Microtunneling saved $3.5 to $5 million from the estimated cost of a shored excavation and avoided a railroad and contaminated valley fill. A slurry microtunnel boring machine (MTBM) was used for two segments where groundwater was present and a wheel excavator MTBM was used for one segment where groundwater was not present. This paper describes design and construction of this project that was completed within 2% of the bid and engineer’s estimate.

Jan 1, 2001

By K. T. Cunningham

The Oakfield, New York Hine of the United States Gypsum Company is a shallow, room and pillar mine developed in the Camillus Formation of Silurian Age on the up-dip edge of the northern Appalachian Basin. The gypsum comes to subcrop beneath a variety of glacial materials and is subject to solution activity by groundwater. A geologic environment unfavorable to mining activity is thus created. Since 1978 seismic studies have been used to supplement core drilling to determine a conservative boundary between normal and questionable mining environments. A single channel seismograph, originally in use, is now replaced by a twelve-channel unit and is used to determine bulk material velocity which is the basis for defining the mining limit.

Jan 1, 1987

By J. F. Stenebråten, W. P. Johnson, D. R. Brosnahan

Carbonaceous material (CM) from ores of varying preg-robbing activity from Barrick Goldstrike Mines Inc. (BGMI), Nevada, was characterized in terms of its functional group content, hydrocarbon content, elemental composition, and humic acid content. FT-IR analyses showed neither the presence of hydrocarbons nor of carboxylic, phenolic, or sulfhydrol functionalities. FT-IR bands present included C=C stretching in aromatic rings and C-O-C stretching, indicating presence of oxygen as ether linkages in the carbon matrix. Calculated atomic oxygen to carbon (O/C) ratios did not reveal a trend between maturity of CM and preg-robbing behavior, possibly due to low resolution of electron microprobe analysis. However, the atomic O/C ratios agree with other chemical analysis, indicating that the organic carbon is very mature, similar to or higher in grade than anthracite coal.

Jan 1, 1999

By K. F. Unrug

The identification of the major subsidence areas in the Western Kentucky Coal Field has been made to distinguish the subsidence phenomena on the basis of geographical location Further, this identification process is based upon selected critical geological, topographical, and mining features in the coal fields. The proposed identification of the regions is derived from a comparison of the subsidence potential in a particular area. The most likely severe subsidence areas are compared to those with the probable low subsidence severity. The combination of certain geological and mining parameters involved allows for the derivation of a classification of the subsidence potential. It is recommended that further site specific studies should be performed on this area.

Jan 1, 1986

By A. W. Khair

This paper presents an analysis of surface subsidence characteristics in room and pillar mining using physical models and laser holographic interferometry (holometry). The analysis included the effect of various geometric parameters and different overburden materials (sand and gelatin) and resulted in the formulation of a more realistic model material for laboratory simulation of typical geologic overburden. Previous work using this technique involved the use of sand to model over- burden and detailed results are presented elsewhere (1). The main emphasis of this work was to develop a gelatin based mixture which would provide a better model. Initial work during the development of this model included testing various ingredients and monitoring the time dependent characteristics of the model, such as the surface penetration resistance. This value indicated changing deformability/ridgidity of the model with time. Once several models had been developed, holometry techniques were applied. Initial tests showed that the stiffness of gelatin created a bridging effect over the mine models, thus restricting deformation. At this point, a 0.5 inch (1.27 cm.) layer of sand was placed directly over the mine model with the gelatin mixture on top. The approach was to model different zones of overburden movement that exist as an extraction occurs (2). The sand would represent the caved and fractured zones which occur above the excavated area. The gelatin models the continuously deformed zone which occurs between the fractured zone and the surface. Holometry techniques applied to this model yielded successful results.

Jan 1, 1986

By Dennis L. Boley, Francesco Gallavresi, Donald A. Bruce

The authors describe novel aspects of ground reinforcement and treatment as related to soft ground excavation for tunnels throughout the world. Insitu reinforcement for cut slopes (soil nailing), as underpinning (reticulated micropiles), and as direct tunnel support (infilaggi) is introduced. Ground treatment focuses on new aspects of permeation grouting (by the tube'a manchette system), and on jet grouting-a very powerful and positive new technique. Recent developments in equipment, materials, methods and instrumentation are reviewed, with special reference to major tunnelling projects in Italy and Singapore.

Jan 1, 1987

By B. F. Buie

In South Carolina and Georgia an area about 20 miles wide situated near the inner margin of the Coastal Plain and extending from the vicinity of Columbia, S.C. southwestward about 180 miles to the vicinity of Macon, Georgia is the principal kaolin-producing area of the world. It is especially important as the world's major source of clay used for paper coating. Essentially all of the land known or likely to be productive of quality kaolin in this area is now owned or controlled by producing companies. The least-fully developed portion is that in the vicinity of Wrens, Georgia which has been explored and developed since 1961. For the two decades following the end of world war II, demand for kaolin increased at approximately twice the rate for other industrial minerals. From 1945 to 1965 production increased four-fold. Since 1965 the rate of increase has been less, but the outlook now is that production and demand will double at least once again before the year 2000. A substantial part of this increased demand has come, and will continue to come, from industrial development, especially in the paper industry, outside the United States. The general effect, in addition to a continuing increase in production in the U.S., will be to cause: 1. Intensive research for development of more effective and more economical methods of beneficiation; 2. Concerted research effort to find an economical way of modifying high-viscosity kaolin so that it can be used for paper coating; 3. More active exploration in the U.S. and overseas, especially for deposits to supply the foreign markets; 4. More intensive study of the geological factors responsible for the accumulation of commercial deposits of kaolin; 5. Some modest rise in price, relative to the cost of other industrial minerals. The effect on kaolin producing region of Georgia and South Carolina will be to cause: 1. Working of progressively lower-grade deposits; 2. An increase in the acceptable thickness of overburden; 3. Mining of deposits farther down-dip, the use of which is now inhibited by large volumes of groundwater; 4. Increased threat of invasion of the kaolin in industry's market by substitute materials; 5. A substantial increase in concern over environmental factors; 6. More attention to be paid to the large opportunity offered for mining of silica sand and other co-products.

Jan 1, 1972

By H. H. Murray

Recently developed clay deposits that will impact regional and world markets are described. These deposits, their location, geology, and physical properties are delineated. Kaolins from the State of Para in Brazil and from Ukraine; bentonites from Argentina and India; and palygorskite and sepiolite from China are world class deposits that when processed using modem technology will produce excellent products. Other deposits that may affect regional markets are l<aolins from China, Australia and Indonesia; bentonites from Georgia (formerly USSR) and China; and palygorskite from India and Ukraine. New ball clay deposits that will affect regional markets are in China and Indonesia.

Jan 1, 1999

By L. Alan Weakly

Page one is missing from book

Jan 1, 1982

By J. Hong, K. Han, C. Park, C. Yoon, H. Yoon, N. Kim

The contents of three platinum group metals (PGM-platinum, palladium and rhodium), from the spent automotive catalyst, and two NIST SRM (National Institute of Standard and Technology Standard Reference Material, Used Auto Catalysts) were determined by the X-ray fluorescence (XRF) spectrometry. The XRF technique has been proven to be a fast, effective and accurate method in determining not only PGM but also other solid materials of less soluble for wet digestion analysis. The detection limit of the XRF analysis is better than that of the inductively coupled plasma mass spectrometry which usually requires significant dilution to avoid high dissolved solid concentration. However, the XRF technique suffers from a strong matrix dependent problem. The objective of this study was to examine the applicability of the XRF analysis where the sample matrix was not exactly the same as the standard materials with particular reference to PGM analysis. This study enabled to compare the effect of various matrices including alumina, iron, copper and nickel on determination of the contents of PGM.

Jan 1, 2004

By Nobuharu Isago, Atsushi Kusaka, Kosuke Kawata, Dohta Awaji

"The immediate ring closure method, in which the entire periphery of the excavation area is closed immediately with an initial support within a short distance from the excavation face, has been increasingly used in Japan, especially, as one of the most effective countermeasures against difficult ground conditions in conventional tunneling. For reasonable design of this method, the performance requirements for the initial support should be clearly stated. The analysis of construction data of 30 road tunnels and the three-dimensional numerical modeling based on real data suggest that the immediate ring closure stabilizes the tunnel structure and the ground around it because of the inner pressure effect of the initial support, especially, for low ground competence factor and small internal friction angle. Finally, the bending compressive strength and the cross-sectional geometry of the initial support have to be considered in the tunnel design while considering the earth pressure and ground properties. INTRODUCTION Conventional tunneling methods often deal with difficult ground conditions such as soft ground or squeezing ground conditions. The immediate ring closure method, in which the entire periphery of the excavation area is immediately supported within a short distance from the excavation face (Figure 1), has been increasingly used in Japan as one of the most effective countermeasures against difficult ground conditions in conventional tunneling (e.g. Takahashi et al., 2011; Nakaoka et al., 2013). The immediate ring closure method was empirically identified as effective for reducing ground surface subsidence and tunnel deformation. However, the working effects of the method have not been clarified sufficiently. To improve the design of this method, the working effects of this method and the performance requirements for the initial support need to be clarified. The relation between the effect of immediate ring closure and earth cover has been clarified (Mashimo et al., 2008; Awaji et al., 2013),"

Jan 1, 2016