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By A. R. Rule

This report describes preliminary studies by the Bureau of Mines to develop a procedure for extracting the fluorine from low-grade fluorspar ores in which the CaF2 particles are finely locked in the calcite matrix. A combination of flotation beneficiation and pyrohydrolysis is applied to recover and to liberate the fluorine. Flotation of a finely locked high-calcite fluorspar ore containing only 11.7 pct CaF2 recovered over 92 pct of the fluorspar at a grade of 51 to 52 pct CaF2. Pyrohydrolysis of the flotation concentrate liberated nearly 90 pct of the fluorine as aqueous HF. By this procedure over 80 pct of the fluorine contained in the original ore was extracted.

Jan 1, 1974

By M. Misra

The volume of low-level contaminated soil at the. Department of Energy's Nuclear Weapon Sites are in the order of several million tons. Most of the contaminants are uranium, plutonium, other heavy metals and organic compounds. Selected Physical separation processes have shown demonstrated potential in COD Centratingthe radio nuclides in a small fraction of the soil. Depending upon the size, nature of bonding and distributions of radio nuclides, more than 90 percent of the radio nuclide activity can be concentrated in a small volume of fraction of the soil. The physico-chemical separation processes such as flotation in a mechanical and microbubble tall column cell have shown, promising applications in cleaning up the high volume contaminated soil.

Jan 1, 1995

By William Van Impe

A most renewing and promissing soil displacement screw pile is called the O-pile. The O-screw pile is a soil displacement auger pile based on a screwing in - screwing out procedure. The displacement auger head consists of a discontinuously diameter - increasing steel tip, on top of which the continuous screw flange with variable pitch is mounted. The soil displacement is kinematically ensured by downwardly oriented slots mounted on the auger head at different well chosen locations on the flanges. This leads to a very efficient lower energy screwing-in sequence of the pile and consequently to a high penetration rate. A test loading program of instrumented O-piles has been carried out in order to evaluate the load settlement behaviour, the shaft and tip capacity of the O-pile, including its specific installation parameters.

Jan 1, 1996

Caterpillar’s 797 327-t (360-st) mining truck is currently being tested at the company’s proving facilities. Mine evaluations began in the second quarter. The unit will be commerically available in North America in 2000 and worldwide in 2001. The new model is the largest of Caterpillar’s off high-way truck line. In addition, the company has replaced its 966F series II and 970 F wheel loaders with the966G and 972G models. 797 mining haul truck Caterpillar developed the 797 mining haul truck in response to mining companies seeking to reduce cost per ton in large-scale operations. The 797 is sized to work with loading shovels used in large mining operations. And Caterpillar will match the body design to the material being hauled, to optimize pay-loads.

Jan 1, 1999

By I. E. Wahn, E. A. Boutin

"The Manibridge Mill is unique in its treatment of relatively high grade nickel-copper ore because in the mill design are included one 10' diam. x 10' Maxwell cell, and three 12' diam. x 12' tank cells. These large cells are used as rougher-scavenger cells. Three 8' diam. x 8' tank cells as well are used for cleaning and recleaning of the tank cell concentrate.Flexibility of flow is the main criterion in the tank cell circuit. Targets from these cells are a high grade nickel-copper product with a minimum of talcose gangue.The operation of the tank cells has been encouraging and they have performed well with both low and high grade heads, yielding a high grade concentrate product.Manibridge Tank CellsDescription:The tank cells at Manibridge consist of one 10' x 10' Maxwell cell, three 12' x 12' tank cells, and three 8' x 8' tank cells. The four large cells are currently being used as rougher scavenger cells. The three small cells are used as cleaner cells.Both sets of tank cells consist of Denver steel tank and Super Agitator Mechanisms with steel beam super-structures. The agitator mechanism has a totally enclosed ball bearing spindle housing with a cold rolled steel shaft, and a stanclard standpipe with adjustable collar.The air rings for the tanks were fabricated by Nelson Machinery. Both large and small cells have injection rings with equally spaced air holes in the bottom centre line of the ring.Air is supplied to the tank cells by a Dresser Clark low pressure air blower.The following is a table of pertinent data on the tank cells:"

Jan 1, 1974

By Stephen R. Hunt

This paper summarizes some preliminary results of the Illinois State Geological Surveys current investigation into surface subsidence resulting from coal mining in Illinois. The purpose of the study is to characterize-the vertical movements that may result from various types of underground coal mining. In general there is relatively little published information about subsidence from room-and-pillar mining as compared with longwall mining. The findings of this study, based on mining operations in a variety of geologic settings, delineate the magnitude, shape, and position of the subsidence profile. Comparisons of case histories of subsidence are based primarily on the extraction ratio and the general geometry of the mine (depth, panel width, and mining height).

Jan 1, 1979

By S. Tan

A computer-oriented systems simulator (CMHS) has been developed for analysis of continuous materials handling systems. Special emphasis has been placed in the model on several features which are unique to these systems. These features include periodic pattern of material arrival from several sources, several types of material to be transferred, material dispatch processes, intermediate storage capacities, and multiple material destinations. Both the deterministic factors of the continuous material handling system such as the physical decomposition of the system and the scheme and schedule of its operation and the stochastic factors such as variations of material arrival, material pattern on the conveyor, and avail-abilities of the system elements are considered in the simulator.

Jan 1, 1988

By Alan Bauer

In recent years there has been increasing interest in employing the technique of explosive casting in strip mines. Explosive casting, applied to dragline mining, describes the procedure whereby the overburden is horizontally displaced by blasting causing a portion of the material to be thrown into the previously mined cut. Therefore, it is not necessary to subsequently excavate this waste with the stripping equipment. In addition, allowing the overburden unrestricted movement during the blast most often results in improved fragmentation and enhanced machine productivity. The method is receiving attention because the capital and maintenance costs of stripping equipment has risen rapidly in relation to explosives costs. Improved productivity is necessary to maintain unit costs at an acceptable level.

Jan 1, 1983

By E Westthorp, J Phillips

The detection of ethylene in mined-out ‘goaf’ areas of underground coalmines is an industry standard indicator of accelerated oxidation where the coal temperature has exceeded 100°C. If uncontrolled, this naturally occurring process can lead to spontaneous combustion and catastrophic mine explosions, such as the Moura No 2 mine explosion. Spontaneous combustion trigger action response plans (TARPs) typically use the detection of ethylene as a trigger for definite change requiring immediate reaction, which can include the withdrawal of coalmine workers.Following the completion of sealing of longwall goaves at Crinum North Mine, ethylene was often detected in trace quantities. These trace quantities were below 1 ppm and detected via the bag sampling regime, with the use of a gas chromatograph. Any ethylene detected in these instances was not associated with increased quantities of carbon monoxide to conclusively indicate a heating within the sealed area.Ethylene was only detected in a newly sealed goaf and would not remain present for a period following the sealing. As part of the longwall recovery process, the predominant roof support mechanism during the recovery was the use of timber cribs. It was decided to investigate the possibility of this timber generating ethylene.Preliminary tests were completed by placing timber specimens from several species of Australian native hardwoods in gas bags in air. Over time, some of the samples showed significant levels of ethylene within the bags.CITATION:Westthorp, E and Phillips, J, 2017. Findings from preliminary testing to determine alternative sources of ethylene within sealed areas of underground coalmines, in Proceedings Australian Mine Vent Conference 2017, pp 203–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Ralph H. Sweetser

AT the end of 1943 the charcoal pig iron capacity of the United States was at the lowest point in over 1110 years, with only one strictly charcoal blast furnace in operation, and all others permanently out of blast except one in Tennessee d reported to he running on part charcoal and part coke. Such a decrease in production has taken place in spite of the O.P A.'s high-premium price on charcoal pig iron of +34 per ton f.o.b. furnace in Michigan. Depletion of the hardwood supply within fifty mlles or inure of the blast furnace is the reason why; the deplorable lack of reforesting is the cause.

Jan 1, 1944

By O. C. Blade

A summary of the characteristics of motor gasoline for the summer 1951 is presented in table 1, and for comparison, a similar summary for the summer 1950 is shown in table 2. Trends of some of the more important characteristics over a period of years are shown in figures 1 and 2. As indicated, octane numbers of motor gasolines sold in the United states decreased approximately one-half to one octane unit from the record levels attained during the winter of 1950-51 and are a little below the octane numbers of summer 1950. However, average vapor pressures of the summer gasolines did not change, and certain distillation temperatures varied only slightly from those of the year before.

Jan 1, 1952

By Atmesh K. Sinha

The demand for thermal coal both nationally and internationally is projected to increase rapidly. The marketability of high ETU thermal coal produced in the USA is, however, limited by its high sulfur content. Fortunately, over 70 percent of the sulfur exists in pyritic form. The research conducted at Southern Illinois University indicates that over 90 percent of the pyrite can be removed by simple devices such as concentrating tables, cyclones, or froth flotation cells and the desulfurized coal can be blended with low sulfur western coal to produce EPA compliance coal. Thus, both the low BTU western coal and the high sulfur midwestern coal can be rendered competitive in the utility markets, here and abroad due to improved utilization.

Jan 1, 1983

By W. H. Reck

he need in the mineral industry to treat increasingly larger tonnages has caused a demand for larger installations. In order to limit the size of these installations, it was necessary to build machines with larger capacities or production output. With this aim in mind, WEMCO Division developed the No. 120 WEMCO-Fagergren Flotation Cell in 1967. These large cells have been compared to conventional smaller cells from the standpoint of metallurgical performance, investment costs, power requirements and maintenance requirements in many plants throughout the world. Figure 1 illustrates the size difference of the No. 120 when compared with the No. 66. All results to date indicate the large No. 120 cell surpasses the smaller machines in all categories.

Jan 1, 1969

By AIME AIME

ALFRED WILLIAM GAUGER ??Al" or '?Doc" to his many friends in the coal and chemical industries- is known for his research talents and organizing ability. Appropriately the first public recognition of his technical ability was by the A.I.M.E. in the publishing of a paper by George A. Burrell and Alfred W. Gauger in the "Transactions" for the year 1916. "Al" Gauger was born at St. Paul, July 31, 1892. He graduated in chemistry at the University of Minnesota in 1914. A year later he began his initiation into the mysteries of coal mining when he joined the safety division of the U. S. Bureau of Mines at Pitts- burgh, serving from 1915 to 1917.

Jan 1, 1944

By Stig Eriksson

In Switzerland two major railway systems as shown below in Figure 1 has recently been completed or is under construction: ¦Lötschberg, south of Bern which was commissioned in 2007 ¦Gotthard, south of Zurich which is scheduled to be commissioned in 2016The aim is to increase the transport capacity of the railway system and to transfer more transport of goods to the railway by offering transport of trailers and lorries on the new railway systems. It will have a positive environmental impact but also improve the congested traffic situation of the highways in north-south directionThe Gotthard tunnel is totally 57 km (35 mile) long and the Lötschberg tunnel is 35 km (22 mile) long. Both tunnel systems consist of two parallel single track tunnels connected with cross tunnels at every 333 m (1 093 ft). Additionally there are cross-over tunnels and caverns for installations and operation. In the Lötschberg tunnel, the majority of the excavation has been by Drill & Blast and in Gotthard tunnel the major part is being excavated by TBM.

By Tim Ross

Several shear failures were observed in Shaft #1 at the Mountain Coal Company, LLC, West Elk Mine, after mining longwall Panel 23, 1,100 ft to the east of Shaft #1. It was speculated that this shear damage could be related to differential ground movement caused by in situ stress relief from the ?stress shadow? of the caved zone above longwall Panel 23. A numerical study was conducted to assess the possibility of the shaft shear damage being caused by in situ stress relief and the potential for additional damage to Shaft #1 and two other nearby shafts, due to mining nearby longwall Panel 24. Three-dimensional (3D) models were built in FLAC3D to simulate past and future mining near shafts, the estimated local anisotropic and directional horizontal stresses, and the overlying variable surface topography. The numerical analyses indicated that stress relief due to mining Panel 23 caused the shear damage to Shaft #1and that additional damage to Shaft #1 and the other two shafts, would likely result from mining longwall Panel 24. Additional shear damage was documented in Shaft #1 when longwall Panel 24 was mined, confirming the results of the numerical analyses.

Jan 1, 2006

By W. J. Turbeville

The subject of this discussion is timely. The U.S. phosphate industry is suffering the throes of depression. It's plight is a matter of widespread concern. The future role of the U.S. industry in world markets is of particular interest. If we should prognosticate phosphate supply-demand on the basis of recent history, we would face a puzzling choice of scenario. In 1980, perhaps the best year ever for U.S. phosphate, 54.6 million metric tons of phosphate rock entered the market place. Of this, more than half was exported -- divided almost equally - as rock or phosphate fertilizer. During the last half of 1981 the situation had begun to change.

Jan 1, 1983

By Roger M. Turpening

This study was performed to examine the feasibility of using seismic shear waves to detect the presence of abandoned coal mines. !he Antiquity Coal Mine near Antiquity, Ohio was used as a region of known voids. No attempt was made here to accurately locate the mine tunnels if detection was obtained. The results of this study were positive. Sharp changes in the amplitude of the received shear waves were clear indications of the presence of a fluid (gas or liquid) filled region between the source and receivers. When moving the source showed no change in the received signals it was concluded that the voids existed beneath the sensors. Prior to these tests drilling (SM-3) had determined that a void did exist in this area. This void was confirmed by this shear wave test and two additional voids were found.

Jan 1, 2012

By Alan D. Randolph

A size-continuous breakage kinetics model is postulated and supported with industrial grinding mill data. It is shown that the kinetics parameters include the effects of possible classification at the mill discharge. The estimated parameters were then used in the kinetics model to simulate the behavior of a grinding mill in open and closed circuit operation. While material transport and kinetics are equally important in open loop operation, heavy recycle in a closed circuit make a detailed material transport model for grinding unnecessary. In effect, the mill can be considered as backmixed. This suggests that more emphasis should be placed on modeling the classifier than the development of detailed material transport models for the grinding mill.

Jan 1, 1975

By R. J. Gunderman

A conventional trailing cable connection box on a continuous mining machine was modified by the addition of two innovative devices. These are a pressure vent to preclude buildup of high pressure due to an explosion in-side the enclosure, and a grommet-type cable entry to simplify and speedup cable entering procedures. The innovative devices were evaluated for eight and one-half months in a working section of an underground coal mine. Laboratory tests before and after the in-mine exposure show no measurable change in the devices. Following the favorable in-mine evaluation, technical performance criteria were defined to serve as the basis of approval for the use of the innovative devices. Additional tests to measure comparable gripping of the cable by asbestos rope, substitution rope materials and by the urethane grommet-type entry were included in this effort. Also, literature for the last 80 years was searched. Comments are provided as to how the innovative devices comply with 30 CFR Part 18.

Jan 1, 1982