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By S. A. Suhler

The detection of hazardous geological anomalies through remote sensing techniques is the subject of current research efforts sponsored by the U.S. Bureau of Mines. In this review, hazardous geological anomalies are discussed with respect to the "view" presented along with potential operational concepts for each technique. The design and development of a borehole radar is described with emphasis on the potential range and resolution capability of the system under realistic underground conditions. Results of field tests at two coal mines and at a hard rock future subway location are presented.

Jan 1, 1978

By S. Behl

A major limitation in developing successful selective flocculation schemes is the difficulty encountered in adsorbing the polymeric flocculant only on the desired substrate. In this paper a correlation between selectivity of flocculant adsorption and separation efficiency is outlined and a potential technique to achieve selective adsorption of flocculants is discussed.

Jan 1, 1992

A coal mine located in southern West Virginia recently set a world record for daily low-seam coal production using a Cat automated longwall plow system. In a 24-hour period on April 10 and 11, 2014, the Pinnacle Mine longwall produced 32,411 t (35,724 st) from the Virginia Pocahontas No. 3 Seam, in a seam height of just 1.42 m (56 in.) along the 298-m (980-ft) longwall face. The Pinnacle Mine, located near the town of Pineville and owned by Cliffs Natural Resources Inc., an international mining and resource company, operates a Cat Gleithobel GH1600 Longwall Plow System. A previous record was set by this system at Pinnacle in August, 2012 when 29,423 t (32,430 st) were mined in a 24-hour period. The record was set by the same system, mining its second panel after a comprehensive rebuild was performed by Carter Machinery, the Cat Dealer in that area. The rebuild encompassed a complete rebuild of the headgate and tailgate armored face conveyor (AFC) drive, the headgate and tailgate special AFC pans, the stageloader drives and return end, the complete crusher and all gearboxes for the plow, AFC and stageloader. Carter acquired the rights to sales and aftermarket support associated with the former Bucyrus mining products, both surface and underground, in 2013. ?Supporting and rebuilding a longwall plow system was a new experience for the Carter service team,? said Chris Curfman, president of Caterpillar Global Mining Sales and Support Division. ?However, given the record production results attained by the rebuilt system at Pinnacle, it?s obvious that they are up to the challenge of supporting the underground product lines at the same high standards and quality level that they have been delivering for many years on the traditional Cat surface mining products.? Tom Bluth, president of Caterpillar Global Mining Products Division, said, ?Caterpillar congratulates the Pinnacle team for this great achievement. Without their efforts and dedication this record would not have been possible. To safely deliver that kind of output from such a thin seam is remarkable. We have been privileged to work alongside their team to demonstrate the capabilities of Cat longwall mining technology. ?

By Robert L. Russell

The Bunker Hill Mine, located in the Coeur d'Alene Mining District at Kellogg, Idaho, has been a major producer of lead-silver-zinc ores since its discovery in 1887. The mine has produced over 29 million tons of ore from some 20 to 25 veins and ore zones, and now covers an area approximately one mile in length and one-half mile in width. The active section of the mine extends from 2500 ft above sea level to 1600 ft below sea level. Production is presently at the rate of about 1700 tons of ore per day. A two-mile adit, the Kellogg Tunnel, at the 2500 elevation, provides access to the main shaft area. Ore is hoisted to the adit level through a 5000-ft, 500-inclined shaft, extending to the lowermost haulage level 1200 ft below sea level. Primary shaft service for men and materials is supplied by three major internal, inclined shafts equipped with double-drum hoists. Present production requires ten levels to serve for mainline track haulage. These range up to 5000 ft in length and are either 200 or 400 vertical feet apart. Also, many intermediate levels exist throughout the mine. The conventional and autoloader mechanized square-set and cut-and-fill mining methods used throughout the mine have been the subject of a recent paper(l). One-third of current production is from vein-type ore bodies which are long distances from main shaft areas. Such veins generally dip about 450, have relatively narrow widths of from 3 to 20 ft, and usually contain less than 500,000 tons of ore. For many years, ore bodies thus situated have been developed by means of a separate inclined, timbered service shaft-raise connecting two or more main haulage levels. These commonly range from 400 to 1000 ft in vertical extent and are equipped with 25 to 50 hp electric, single-drum hoists. Intermediate levels are driven as conventional track drifts at 100-ft vertical intervals between the haulage levels. Ore and waste from the intermediate levels are trammed to orepasses for delivery to the lowermost haulage level servicing an ore body. The final result may be visualized as a number of small mines within a large mine. The problems of high development costs and high total development time, and the large amount and high cost of providing materials handl ing and ore haulage service while producing from this isolated type of stope block, made it desirable to consider totally new approaches in developing and mining a number of similar areas.

Jan 1, 1971

By R. Wensel

A composite material consists of two or more dissimilar components. These dissimilar components retain their identities when mixed together and contribute to the properties of the composite. A composite usually consists of two parts, the matrix and the reinforcing material, or extender that is added to the matrix. Typical materials used as the matrix in composites are metals, polymers, and ceramics. The reinforcing material can be added for any number of reasons. For instance, if the matrix is expensive, an inexpensive filler may be added to the matrix to lower the cost of the product without sacrificing properties. An example of this is calcite (CaC03) which is added to systems such as polyvinyl chloride (PVC), to lower the cost. Reinforcements may also serve as a means to enhance the properties of the matrix material. For example, carbon fibers are frequently added to plastics to increase their strength, and glass spheres may be added to plastics to improve flexural strength. Mg(OH)z is added to polymers to give the property of fire retardancy. The latter is the focus of this paper.

Jan 1, 1995

By Wendell R. Peters

Shallow underground voids resulting from early coal mining and other resource recovery activities over the past several decades are now being recognized as a significant cause of ground subsidence problems. Uncertain knowledge of abandoned coal mines also imposes potential hazards in current mining operations since water inundation or the release of methane gas is a serious hazard when mine excavation operations break into an abandoned mine. Requirements for detecting and mapping subversive man-made tunnels in previous work has led to the development of a surface- operated automatic earth resistivity survey system and associated computer data processing system for military applications. Field demonstration tests of this system have resulted in successful detection of tunnels at depth-to- diameter ratios greater than ten to one. Under the sponsorship of the Bureau of Mines, a similar high-resolution earth resistivity system was designed and constructed for use as a potential means of detecting coal mine workings. The hardware and software aspects of the new system are described together with applications of the method to the survey and mapping of abandoned coal mine workings. Field tests are presented showing the detection of both air-filled and water-filled mine workings.

Jan 1, 1981

By Roussos Dimitrakopoulos, Liam Findlay

Semimobile in-pit crushing and conveying (IPCC) systems can help reduce truck haulage in openpit mines by bringing the crusher closer to the excavation areas. Optimizing a production schedule with semimobile IPCC requires integrating extraction sequence, destination policy, crusher relocation, conveyor layout and truck fleet investment decisions. A mining complex with multiple mines and IPCC systems should be optimized simultaneously to find an optimal schedule for the entire value chain. An integrated stochastic optimization framework is proposed to produce long-term production schedules for mining complexes using multiple semimobile IPCC systems. The optimization model has flexibility to select the crusher locations and conveyor routes from anywhere inside the pits. The framework uses simulated orebody realizations to consider multielement grade uncertainty and manage associated risk. A hybrid metaheuristic solution approach based on simulated annealing and evolutionary algorithms is implemented. The method is demonstrated using an iron ore mining complex

Nov 1, 2024

By R. J. Sweigard

One possible alternative for disposal of flue gas desulfurization (FGD) by-products is use as backfilling support material in highwall mine adits. The finite element method was used to analyze the variation of stresses and displacements within and around a highwall adit backfilled with FGD materials. The engineering properties of the rock material and the optimum mix proportioning of the FGD materials were obtained from laboratory tests. Finite element analyses show that, for the case in question, the roof displacement would decrease about 48 percent and the peak stress could be decreased about 58 percent. The study indicates that fairly weak FGD materials can eventually lead to stability of backfilled highwall adits.

Jan 1, 1996

By Someswar Kesh, Gavin J. Faulkner

Introduction Powered supports in longwall mines essentially operate under two conditions: 1. Static (non-working) 2. Dynamic (working) There is a variety of static conditions which may exist in a mine. These may include a temporary stoppage of work for a few minutes or stoppage of work for days because of strikes or lack of demand for coal. Studies on pressure behavior were made during brief stoppages of work (few hours) as well as a long stoppage of work (two weeks). In dynamic conditions, the pressure variation on supports is expected to follow a certain pattern. However, in many cases that does not happen. Pressure-time characteristics of each leg of the supports were studied. This paper discusses the research findings of the studies made on powered support pressure behavior under both static and dynamic conditions. Studies on Pressure Variation in Static Conditions It has been noted (Brenner et a1.,1975) that the pressure distribution on mechanized longwall faces is random in nature and changes with time and position along the face. Figure 1 and Figure 2 show the distribution of support pressures for the front left leg of supports in two different mines. In both the cases it can be seen that the variation of the support pressures along the face is indeed absolutely random. However, the nature of randomness in both the cases is very different. The data in Figure 1 (Mine 1) is much more random than the data in Figure 2 (Mine 2). This can also be seen from the standard deviation of the data (81 26 Pa versus 4000 pa) . By comparing the results of ten other sets of data the same conclusions can be arrived at. Since it was found that in Mine 1, the pressure on support legs was extremely random, batches of ten supports each were taken and the mean pressure plotted. This mean pressure line is shown in Figure 1. It was expected that this would smooth out the variation due to individual props and reveal a better picture of the support pressure distribution. For the case cited, the standard deviation is lowered to 5043 Pa from 8126 Pa which indicates that, on an average, the supports tend to take loads more uniformly, however for individual support legs the load on the supports is very random. The significance of this is that, if the supports are selected on the basis of theoretical load calculations alone (based on the roof block concept or some other concept), only the mean value of the support load required will be known. In the case of a pressure distribution with a high standard deviation, some supports selected on the basis of mean value will fail, while others will be supporting low loads. Hence, for proper selection of support capacity, it is not only necessary to know the average load but also the expected nature of the distribution. The only reason why the supports are supporting the roof in Mine 1 well is the fact that the yield load is above the highest level of load attained. If Mine 2, which has a much higher average load, had the same sort of standard deviation, the loads on the individual legs could easily exceed the support load. For example, if the pressure distribution followed a normal curve and the mean pressure was 36,700 Pa with a standard deviation of 9000 Pa, it is possible that 67% of the supports will be within the pressure range of 36,700 plus or minus 9,000 Pa, or 22,700 and 45,700 Pa. Many of the supports could then exceed the yield load of 40,000 Pa. It is clear then that the mean load is an inadequate criterion for estimating support resistance. The nature of the problem is statistical and such an analysis should therefore be made as far as pressure data are concerned. Statistical Analysis of Pressure Data. In general, in longwall mining and other geo-mechanics studies, it is extremely difficult to specify the exact nature of the distribution of a variable. Under these circumstances, probability

Jan 1, 1986

By A. W. Fletcher

A nickel-copper sulphide concentrate was treated in a pilot plant at Warren Spring Laboratory during 1961, by a hydrometallurgical roast-leach- solvent extraction process devised to cleanly separate the metal values, and produce acid sulphate liquors containing the metals. It is shown that 86 percent of the nickel and 95 percent of the copper could be leached from the calcine, after a sulphatizing roast on finely ground flotation concentrate. Iron was removed from the leach liquor by limestone neutralization with a small loss of values. Copper and nickel were separated by solvent extraction with naphthenic acid in kerosene after partial neutralization of the iron-free liquors with ammonium hydroxide. Hydrogen sulphide and chlorine were used to remove zinc (and residual copper) and cobalt impurities respectively. The recovery of pure copper and pure nickel, by electrowinning, from the acidic solvent extract strip liquors finally produced, appears technically feasible.

Jan 1, 1964

By W. Nazarewicz

The introduction of continuous papermaking in the early 1800's was the beginning of the industry as we know it today. Since that time, the majority of the paper produced has employed an acid process. However, in the mid 1960?s, European producers began a transition to an alkaline papermaking process. Early European mill conversions to alkaline papermaking begun in the 601s, accelerated during the 1970's influenced by the dramatically higher cost for OPEC energy as well as the high cost of fiber and imported filler clay.

Jan 1, 1986

By R. W. Carn, D. Vincent

During the next 15 years, US coal production is expected to double, with the increased production evenly divided between the East and the West. Along with greater production, coal export markets should increase dramatically from East, West, and Gulf Coast ports. The annual overseas export capacity of US coal-loading terminals is expected to rise from 147.1 Mt (162.1 million st) in 1981 to a minimum of 278.1 Mt (306.6 million st) in 1985, according to the US Maritime Administration. Increased coal production and use will lead to more development of import and export terminals, a vital link in the coal transportation chain. With continually escalating capital costs and the competitive markets that the terminals will serve, a well designed and efficient terminal is necessary. This article begins a two-part series that presents concepts presently used in coal export terminal design. Part I looks at site selection factors and equipment needs, while Part II will examine environmental considerations in building a terminal as well as typical capital and operating costs. The world is nearing the end of the oil era. In a few years oil will not be available to sustain the growth rate and increasing standard of living we have known in our lifetime. The big question is what energy era are we moving into? With the decline of readily available oil reserves and rapidly increasing prices, many countries are trying to switch to alternate energy forms. While intensive efforts to find new oil reserves continue, alternate energy sources such as natural gas, coal, synthetic fuels, nuclear, hydroelectric, solar, and wind power are being developed. Recent indications are that coal is expected to bridge the energy gap over the next 25-30 years until the technology and economics of the alternate energy forms reach satisfactory levels. Use of coal for energy is receiving strong attention due to its long-term availability (200-300 years minimum), relative ease of development, and its low cost per unit of power produced. By the year 2000, it is expected that 25% of world energy supply will be met by direct coal combustion and possibly another 5-10% by synthetic fuel from coal. Coal's expanding share in the world energy market, along with an increase in coking coal requirements, will result in a large increase in the world's seaborne coal trade. Recent statistics and projections for the future are shown in Table 1. This phenomenal development rate includes increases in both coking and thermal coal requirements. Because of the rapid increase of seaborne coal trade during the last 10 years and the even greater projected increase of trade to 2000, various sectors of the coal industry are faced with enormous technical challenges and huge investments in equipment, land, transportation systems, and port facilities. Very large bulk terminals are under development throughout the world. Latest surveys indicate that there are about 30 new coal export and import terminals under consideration and at least 30 existing terminals have expansion programs planned or underway. With the high cost of borrowed capital and rapid inflation rates there is great emphasis on new planning and design techniques to minimize capital and operating costs of coal transportation systems. Terminals A total coal supply system can be considered to consist of one or more mines; a train, barge, truck, or other haulage system; an export terminal; a fleet of bulk carriers; a receiving terminal; and possibly, local inland distribution networks that include barges and railways. Terminals, though only a small link in the total transportation system, play a key role in overall system efficiency. At ports or inland distribution centers, terminals act as transportation links bringing trains, ships, barges, or trucks together for cargo transfer and temporary storage. A well-designed terminal can provide maximum independence between two modes of transportation and optimum freedom for intermodal interference. A terminal acts as a buffer between the two transportation modes by providing sufficient storage capacity so a ship need not wait for its cargo on, for example, a train-by-train basis, but can load immediately from the ready stock. Similarly, a train need not wait for a ship to unload its contents but can dump immediately into storage. A terminal also can be used to properly mix various types of coal to satisfy a buyer's requirements. Consider the relative value of various production and transport segments for a typical steam coal

Jan 6, 1983

By J. P. Ducarme

The eastern U.S. contains vast reserves of thin seam coal deposits, particularly in the Appalachian mountain region. These typical 355 to 710 mm thick reserves are difficult or uneconomical to recover with present technology. The U.S. Bureau of Mines is developing technology that would allow nearly 100% recovery of thin seams in these mountaintop regions. This paper details the research that has been conducted on these new techniques and presents results of testing on a cross-ridge full-scale physical model.

Jan 1, 1994

By R. D. Stewart

Abstract. Induced fluorescent sorting is a means of beneficiating an ore by selective labeling with a reagent combination which fluoresces when activated by ultraviolet light The reagent combination normally consists of a surface active compound and a fluorescent dye. The surfactant adheres selectively to a specific surface and carries the dye with it. Upon activation with ultraviolet light, the labeled pieces, in the size range 1.27 cm to 20 cm (0.5 to 8 in.), are detected during free fall by photosensitive cells and ejected by water jets. Either ore or gangue may be labeled.

Jan 1, 1980

By William M. Warren

Recent sinkhole activity in carbonate terranes of Alabama has resulted in damage to transportation lines, structures, utility lines, and property in general. Active sinkhole development and subsidence has been well documented in Alabama, Florida, Pennsylvania, and South Africa. An excellent example of the potential danger resulting from this activity is the spectacular collapse under a South African gold ore crusher plant that resulted in the death of 29 men in 1962. Due to the severity of the problem in certain localized areas in Alabama, a detailed investigation is being undertaken by the Geological Survey of Alabama and the U. S. Geological Survey. One of the most promising techniques is the application of aerial photography and thermal infrared imagery. Conventional and modern remote-sensing techniques are being used in Alabama to locate and define areas of sinkhole activity and to determine which areas are most prone to its occurrence.

Jan 1, 1975

By R. H. Thorpe

In the earliest days of mining coal the obvious method was by bord and pillar working. Longwall in Britain developed from this as an expedient to overcome bottlenecks arising from ? 1) increasing depth of seams causing roof control difficulties; and 2) ventilation problems. This system became almost universal particularly in the thicker seams, where faces of up to one mile in length were not uncommon. Coal getting in these faces was usually by pick and shovel, filled into small waggons of up to 15 cwts capacity. These waggons ran on rails laid alongside the coal face and were often taken away from the face to the main haulage roads by horses. The roof was supported by rigid props and the wastes were normally controlled by strip packing. This system of mining was very flexible and worked well down to sections of about 3'6"

Jan 1, 1976

By C. A. Holley

The generation of coal fines is a growing problem which has serious environmental and resource recovery Impact. Several methods of agglomeration are studied including the production of briquettes for the consumer market. Simplified process flow diagrams, "order of magnitude" plant capital cost and operating costs are presented.

Jan 1, 1986

By R. R. Young

Good afternoon gentlemen. It is always a pleasure to talk about a subject dear to our hearts--the high speed transfer of bull; materials. Specifically, today we will be reviewing the engineering approach to an age old problem of ship loading and unloading. You may be puzzled by the title of this paper and we will attempt to explain this for you--particularly the use of the words "New Era", since high speed automated facilities are nothing new to the material handling engineer. The new era in material handling designs refers to an all out concerted effort to provide custom engineering tailored to specific operations and economic requirements of the client. It shuns hardware type of engineering wherein existing machines and devices are dusted off and reapplied. It provides automation when automation can be justified and it exemplifies the application of systems engineering to solve specific problems.

Jan 1, 1967

By M. A. Girts

Wetlands can be constructed inexpensively on mined lands to treat small flows of acid mine water. Metals are removed from the water by the wetland vegetation and indigenous bacteria. Full-scale field tests initiated at over 20 mine sites during 1984 and 1985 indicate that water quality can be upgraded to meet discharge standards with relatively minor maintenance requirements. Iron concentrations of 25-85 mg/L in the influent water fall to less than 2 mg/L during flow through a small wetland. Manganese can also be removed, though somewhat less efficiently. At the discharge, pH is easily raised to 6 by flow over limestone.

Jan 1, 1986

By Stephen C. Moore

The Grossschloppen vein-uranium deposit, Bavaria, West Germany, was examined utilizing underground workings during 1980-82 by Esso Erz GMbH, an affiliate of Exxon Minerals Company (EMC). Geologic evaluation entailed dense drilling of a portion of the deposit from workings constructed specifically for the program. Discovered in 1977, the deposit was initially explored by surface diamond drillholes which allowed definition of a 30-60 m wide vein system discontinuously mineralized along a 1000 m strike length and to at least a 450 m depth. The underground program was conceived as a cost effective procedure to answer questions on vein correlation, grade continuity and variability. A 1200 m decline allowed access for detailed sampling of approximately 10% of the known area of mineralization. Fanned drillholes, logged by gaga probe, were spaced to provide intersections of veins at 10 to 20 m intervals. Six cross cuts also penetrate the pitchblende and uranophane mineralization which occurs in 0.1 to 2.5 as thick quartz veins. Detailed cross-sections and level plans were constructed for resource estimates of the intensively studied portion of the vein system. The program resulted in the discovery of local, high grade areas and an average grade in the evaluated area nearly double that expected from surface drilling.

Jan 1, 1983