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By Keenan. Albert M

The challenge of mining coal seams having a pitch of 30 degrees is one not frequently found in the United States, due primarily to the scarcity of such deposits. However, in the Thompson Creek District in Pitkin, Colorado, such a challenge exists to produce high quality medium volatile coking coal, and development of a longwall system is underway. The deposits under consideration are those of the Anschutz Corporation Inc. of Denver, Colorado, which are not in a virgin state. The properties were originally mined by the Colorado Fuel and Iron Corporation from 1894-1907, and by the Thompson Creek Coal and Coke Corp. from 1953-1966. Approximately five and one half million tons of coal have been mined by the above companies, attesting to its quality. The cessation of operations in both instances was occasioned by economics. Both companies employed a room and pillar system of mining, but being denied the use of high capacity mining and loading machinery because of the excessive pitch of the coal seam. This resulted in an unfavorable productivity expressed as output per man-shift, and thus the high cost of production occasioned by hand loading and semi-mechanization dictated cessation of operations. The specific location of these deposits are in Pitkin County,

Jan 1, 1971

By R. R. Godard

The practice of dust abatement or control is not new to any operation of United States Steel Corporation. This report will review those activities, past and present, within the five operating districts of United States Steel-Coal Operations with specific reference to mechanical and continuous mining, and including both the health and safety aspects of the problem. Obviously, the first principle of dust control is to inhibit its formation If this is not practical, steps may be taken to prevent its becoming airborne. Airborne dust control can be realized by either collecting it at the point of generation, diluting it with large volumes of air to reduce concentration, settling it by various means, or with reference to ignition hazard only, render it incombustible by neutralization with an inert material. These basic principles have been verified by the work of many, including the Bureau of Mines, U. S. Department of Interior, Bituminous Coal Research, Inc., and the Mining Research Establishment of the National Coal Board of Great Britain. Their application to every day mining problems is best illustrated by the following examples.

Jan 1, 1967

By Jean-Michel Rendu

Accurate modeling of the semivariogram is an extremely important step in the geostatistical analysis of mineral deposits. Automatic fitting of a mathematical model is often possible but not necessarily desirable. Significant geologic and statistical information must be taken into account in the fitting process, which is not always available to the computer. Manual fitting of the model is, on the other hand, extremely time consuming. Interactive graphics are best suited to optimize the process. A number of interactive methods are described, which are adapted to the modeling of semivariograms in one-, two-, or three-dimensional environments.

Jan 1, 1982

By Neville G. W. Cook, John Kemeny

Utilizing the principles of elastic-brittle fracture mechanics, stress-displacement relationships are derived for an elastic solid containing a slip plane consisting of various configurations of collinear arrays of cracks. These models take into account the heterogeneous nature of slip planes as observed in the lab and in the field, and are relevant to the behavior of rock containing faults, joints, bedding planes, and fractures. All of our models exhibit slip weakening behavior, and show regimes of both stable (aseismic) and unstable (seismic) deformation. For given configurations of cracks and applied boundary conditions, our results show explicit ly the energy released through unstable crack growth. For instance, it is found that two equal length cracks growing together release more seismic energy than, say, a large crack growing into a small crack. Also, by allowing cracks to coalesce, our models show multiple stick-slip events without crack healing or other geochemical means.

Jan 1, 1986

By Robert Stefanko

The importance of underground stress instrumentation cannot be minimized. It was Lord Kelvin who said that unless you can assign a number to a quantity,, you know very little about it. Most engineers will agree although this kind of statement is resented by our friends in non-technical fields. Mining is undergoing a revolution from art to science. But how can mining methods be optimized if there is no way of measuring the effectiveness of a given mining method? Do we know how effective a' support is unless we can determine its reaction to the mine structure? How do we assess the need for modifications to existing systems and supports, and how do we measure the effectiveness of such changes? Cut and try techniques are too wasteful of time and energy, and rarely provide solutions to a given problem. The purpose of underground stress instrumentation is to provide answers to some of the above questions -- answers that cannot be obtained otherwise This does not mean that laboratory studies are not valuable -on the contrary. Laboratory and underground studies supplement one another. Rock mechanics had its conception with the study of stresses in homogeneous, isotropic, and elastic models subjected to various force systems. These analyses were valuable inasmuch as they pinpointed possible sources of trouble due to stress concentrations. If the results observed underground did not always agree with the experimental analysis, it was not an indictment of the latter. More probably, the discrepancy could be attributed to the lack of similitude between model and prototype. The more nearly one can simulate underground conditions in a model, the more apt one is to produce results which correlate well-with underground observations. It is impossible to completely simulate underground conditions because all of the significant design parameters have not been recognized and evaluated. What better way can one evaluate these parameters than by underground stress instrumentation?

Jan 1, 1963

By John W. Trammell

The White Pine Mine is situated in Ontonagon County, approximately six miles south of Lake Superior, in the Upper Peninsula of Michigan (Figs. 1 and 2). The ore body mined by White Pine Copper Company occurs in the lower - most 20 to 25 feet of the Nonesuch formation, a series of middle - to upper Keweenawan shales, siltstones, and sandstones. This paper elaborates on the solution of problems in ore grade control and mine planning arising from the presence of an essentially barren sandstone stratum within the ore body.

Jan 1, 1964

By Robert E. Hershey

The phosphate industry is the fourth-ranking mineral industry in Tennessee; it has an annual value of 13,000,000 and a yearly production of almost 2,000,000 tons of phosphate ore. Tennessee, at present, is second in rank of phosphate production in the United States. In accord with the importance of this mineral commodity, the Tennessee Division of Geology, is conducting a continuing study of the industry' and the raw s, materials upon which it is dependent. Of the three type's of phosphate found in Tennessee, the brown phosphate rock of the Bigby faces of the Bigby-Cannon limestone is by far the most extensive in occurrence and is the only type being mined at the present time. Because of the importance of the brown phosphate ores, our Division has mapped , in detail the outcrop pattern of the Bigby facies of the Bigby-Cannon limestone. The geologic mapping was done by Dr C. W. Wilson, Jr. and others under his super-vision and the geology plotted on 7 1/2-minute topographic maps, with scale of 1 to 24,000 or 1 inch equals 2,000 feet. These maps will be available for use in the near future and will be published later-with complete geologic coverage.

Jan 1, 1960

By Y. Jinnouchi

An air-pulsated jig has been widely adopted as a main coal washer. It may be mainly because of its many technical and economic features such as large capacity, low running cost, long life, etc. However, the recent increasing demand of fuel coal requires a higher productivity and efficiency of the air-pulsated jig. To fill this requirement theoretical and experimental investigations have been conducted on model and practical jigs in Japan. This paper generalizes the results of these investigations. In jig operation it is essentially of the most importance to create efficiently the pulsation of the water best suited for coal washing. The optimum pulsation should be determined by the theory of jigging process, and the method to realize it by that of pulsating mechanism.

Jan 1, 1982

By Richard G. Almes

Since the failure of a major coal refuse disposal embankment and impoundment in the Buffalo Creek watershed near Man, West Virginia in early 1972, there have been extensive changes in the design and construction requirements for coal refuse disposal facilities located throughout the United States. The primary emphasis has been on improving the safety of these facilities, particularly for impoundments which are capable of storing millions of gallons of process water and storm runoff. The Mine Safety and Health Administration (MSHA) of the U.S. Department of Labor (formerly the Mining Enforcement and Safety Administration, U.S. Department of interior) has been the lead federal agency in promulgating regulations pertaining to coal waste disposal. In 1974 and 1975, studies were undertaken by our firm under contract to the Mining Enforcement and Safety Administration to prepare a comprehensive engineering and design manual to be used by operators and engineers in the planning and design of coal refuse disposal facilities with the intent ion of avoiding any more Buffalo Creek failures. The resultant 800-page document addresses major subjects such as safety, environmental controls, and cost. Specific topics include characterization of coal refuse, classification of disposal facilities, project planning, geotechnical investigations, testing and design requirements, hydraulic and hydrologic design, environmental factors, operations, and monitoring, instrumentation, and maintenance.

Jan 1, 1980

By R. J. Morlock

Prior to 1912, coal research for Republic Steel, Corporation was limited to a periodic box test conducted in a commercial coke oven. Then in 1912, a Koppers movable-wall test oven was -built to research wall pressures for selected blends and to conduct other varied research work. In the 1950's economic pressures caused a reassessment of position resulting in the establishment of a Coal and Coal Chemical research group in 1956. In 1958 this group, along with other groups of research endeavor were incorporated into the new Republic Steel Corporation Research Center at Independence¬ Ohio. Currently this section is divided into four groups. 1) Coal Preparation, 2) Coal-Chemicals, 3) Coal Characterization, and 4) Coal Carbonization. The objective of each group is described, and a brief listing of the work done under the first three groups is indicated. A more detailed description of the studies by the Coal Carbonization group of the coking characteristics of Republic Steel Corporation's coals as blended among themselves or in conjunction with selected purchased coals follows. The wall pressure, contraction, and stability index criteria are specified, and the method of assessing these criteria as a function of blend composition is indicated.

Jan 1, 1963

By A. K. Sinha

Ever since electricity was introduced, electrical injuries and electrocutions have continued to occur regularly in coal mines. An analysis of the two hundred cases of electrocutions which occurred during 1956 to 1970 indicated that over 50 percent of the incidents were caused by the ineffectiveness or lack of electrical grounding. Research shows that various types of arbitrarily designed ground beds are in use and that the ground resistance and current are often very high and subject to wide seasonal variations. The results of a recent research are discussed in this paper.

Jan 1, 1980

By Robert H. Scott

Developments during the past few years have brought coal-based composite fuels to commercial readiness. During the next few years, composite fuels will become available from a number of suppliers. Potential users must evaluate the combustion properties of these fuels to determine equipment and operating changes required for their use. Most work to date has been done with boiler applications. However, many potential non-boiler applications exist in the metals and minerals industry. These applications require specific evaluations appropriate for the processes involved.

Jan 1, 1982

By W. A. Vine

Next year, in 1964, Butte will celebrate its Centennial. It was in May, 1864, that the first recorded mining activity took place. During that summer, several rich placers were found on Silver Bow Creek and its tributaries, and a gold rush followed. As placer mining proceeded in the creek beds, the quartz lodes on the hillsides were located and the veins were prospected. Mining in Butte entered its second phase when the rich silver mines, the Alice, Moulton, and Lexington, were opened. The silver boom lasted until the decline in the price of silver in the early 1890's forced the closure of many of the mines. An indication of the beginning of the copper mining era in Butte was in 1866 when it was noticed that green copper carbonate discolored some of the, lode material. It was not until ten years later, however, that the Anaconda and St. Lawrence claims were located by Michael and Ed Hickey. The claims were sold in 1880 to Marcus Daly and in 1881, Daly obtained financing and organized the Anaconda Silver Mining Company to exploit the vein The silver venture was a failure because of the predominance of copper which diluted the bullion to only 400 fine.

Jan 1, 1963

By Clarence Hardy Long

In January of 1969 the United States Department of Health, Education and Welfare, through the National Air Pollution Control Administration, published a series of Air Quality Criteria (4'S) and Control Techniques (6,7) for air pollutants in compliance with the 1967 Clean Air Act which will affect the operation of all fuel burning equipment in the very near future. The design of equipment for the future which will use fossil fuels will also be affected. The purpose of this paper is to discuss some of the modifications which might be anticipated in the future for fuel burning equipment. One class of the several air pollutants looked at first by the USDHEW was the sulfur oxides. Other pollutants, such as nitrogen oxides, will be studied and controls for these will supposedly be written in due time. The obvious use of low-sulfur fuels, coal, oil and natural gas is suggested by the Control Technique(6). Conversion to other sources of power, such as nuclear energy and hydropower, is also suggested. The statement is made that since possible hydroelectric sources are limited and nuclear plants are not yet available on a large scale, the changeover to these sources of power will not be overnight. The bulletin (6) suggests that one possible solution in some areas may be the use of low sulfur coals for short periods of time during periods of severe air pollution. A curve showing the effect of this was given in the 1969 April issue of the Power magazine, where A. E. Boyer and F. B. Kaylor of Stone and Webster also described a computer program called DOSAGE which might be used to check weather, temperature, humidity, wind direction and velocity, and sound an alarm when that 0.1% of the time per season is here that requires the use of low-sulfur fuel. Inversion is eminent! Once this has passed operation on regular fuel may be resumed. This would mean a separate storage

Jan 1, 1970

By P. K. Muduli

The number and the type of trucks and shovels are two important factors in determining the optimal design parameters of an open-pit mining system. Characteristics of trucks' arrival and service-time distributions determine the performance measures of a truck-shovel system when it is modeled as a closed queuing network. In all of the previous analytical queuing studies of truck-shovel systems, trucks are assumed to be identical with respect to their arrival and service-time distributions. This assumption, although desirable for reducing computational difficulties, causes either underestimation or overestimation of the performance measures depending on the number and type of equipment used in the model. The relative error in performance measures could be significant when the number of different types of trucks and shovels is large. In this paper an analytical method is proposed to model the truck-shovel system as a multiple-chain closed queuing network. This approach would provide the capability of estimating system performance measures for planning purposes when the truck fleet is not necessarily composed of identical trucks. An example of truck-shovel systems is discussed to show how the incorporation of different types of trucks does affect performance measures.

Jan 1, 1996

By Harold F. Yde

Hydraulic tailings fill in the Butte deep level mines was based upon studies made in 1958 by the Anaconda Company Mining Research Department, which published Bulletin No. 35, entitled "Hydraulic Stope Filling". Since then, many things have changed. At the time of the Research Departments study, dry mine tailings were hauled by rail cars from the Anaconda tailings ponds, twenty-five miles distant, to the underground mines' tailings fill plants at the Leonard Anselmo, and Mt. Con Mines. Now, with the installation of the new Weed Concentrator in Butte, tailings is delivered by pipeline to a cyclone at the Kelley Shaft, and stope filling has become more highly automated and streamlined. Presently, mill tailings at approximately thirty percent solids by weight, is pumped from the concentrator, eight thousand feet horizontally and upward, to the Kelley Fill Plant, where they are dewatered and deslimed by three Krebs Model D20B Cyclones, which discharge the material into the cased and grouted mine delivery bore holes at desired densities up to seventy percent solids. The vertical boreholes and four-inch rubber lined Victaulic pipe carry the material downward to horizontal distribution lines, which in turn tap into the stops-filling, three inch, unlined steel Victaulic pipelines. The slurry may travel several thousand feet before it finally discharges into the stope, where it lends support to the mined-out area.

Jan 1, 1969

By John F. Clarkson

White Pine Copper Company built and operated, from August, 1962 through May, 1963, a pilot plant to recover copper using a cyanide percolation leach of the sand fraction (+400 mesh) of the mill tailings (1, 2, 3). The pilot plant runs were metallurgically successful and preliminary engineering studies for a full scale operation were completed under contract by an outside engineering firm. Unfortunately, the net return projected at that time did not justify the proposed capital' investment. In the summer of 1973 the project was revived. The rise in selling price of copper over the previous ten years, compared to the projected operating cost of the leach plant, increased the calculated net return on investment with the most recent figures showing a 30% DCF. Basically, the reason for this favorable shift in profitability was that the cost for many of the reagents did not go up as fast in the previous ten years as did the selling price of copper. Using the Chemical Marketing Reporter costs, NaCN sold for 18.3¢/lb in 1963 and 20.75¢/lb in August, 1973. During this same period H2S04 went from $23.50 per ton to $35.90 per ton. In comparison, producer's prices for electrolytic copper were 31¢/lb in 1963 and 619 in 1973. Thus the price of copper went up 97% while the two reagents only increased 13% and 53%, respectively. The capital investment also escalated but, again, not to the same extent as the selling price of copper. These price differences no longer are valid' but they did provide justification for reexamining the project.

Jan 1, 1975

By Kendrick C. Hardcastle

Although the basic techniques employed in hydraulic pumping in open pit mining have been practiced throughout the better part of this century, only relatively recently have studies of' sufficient depth and scope been conducted to improve these techniques. This paper will point out the basic techniques involved and some of the more recently discovered data concerning hydraulic pumping, Inherent in all hydraulic transportation systems apart from the consideration of transportation cast, is the outstanding advantage of slurrying the matrix at the mining pit so as to provide a lengthy and thorough soaking and washing of the material while in the pipe line and thereby reduce the necessity for washing, scrubbing and other treatment in the beneficiation plant. This is quite important in view of the constant increase in demand for a cleaner product.

Jan 1, 1964

By L. G. Kirk

The Mississippi embayment ball clay region, including western Kentucky, western Tennessee, and northwestern Mississippi, accounted for more than 95% of the total U.S. ball clay production during 1985. Other producing states during the year were Texas and Maryland. The U.S. Bureau of Mines reported total domestic production for 1985 of 910,000 short tons. The United States exports approximately 20% of the annual ball clay production. Geologically, the ball clay deposits are sedimentary in origin and occupy the north- eastern flank of the Mississippi embayment. The commercial deposits have been confined to the Claiborne and Wilcox formations within mid to lower Eocene and upper Paleocene age strata. The deposits are lenticular in nature and highly variable in areal extent and thickness. They exhibit very abrupt lateral boundaries and are bounded laterally and vertically by unconsolidated sands, silts, and waste clays.

Jan 1, 1986

By Bobby P. Faulkner

Allis-Chalmers has combined a new heat transfer device, called the ROLLER GRATE, with a unique processing scheme, resulting in the ROLLER GRATE Oil Shale Processing System of Allis-Chalmers. In order to test both the process and the equipment, a batch Process Development Unit (PDU) ROLLER GRATE retort was designed and built. This unit vas designed with the flexibility to process shale over a wide range of test conditions in order to demonstrate the attributes of the oil-shale processing system. Instrumentation on the PDU and extensive sampling of the effluent streams permitted the PDU test data to be used in the design and scale-up of the process. Over 30 tests have been conducted with Colorado shale, and over 25 tests have been run with an Indiana shale. In addition, rests have been run with California and Utah tar sands.

Jan 1, 1983