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By H. P. Greenwald

[In many coal-mining countries, during he pest decade, there have seen made extended studies and accurate measurement of movement of roof strata, tests of the physical properties of specimens cut therefrom, and tests of the strength of end load on artificial supports. Naturally, such studies have been more extensive in European countries, where mining conditions are less favorable than in the United States. As a part of its work in the conservation of coal resource and prevention of accidants in mines, the Bureau of brines began systematic measurements of the movement of roof strata to in coal mines in the fall of 1935. It was decided- that, in the beginning, work on a rapidly retreating rib line in a mechanized mine would give the greatest amount of information in a reasonable time. To this end w cooperative tine agreement was made with the Pittsburgh Coal Co., through Dr. L. E. Young, vice: president in charge of operations, for conduct of work in that company's Montour 10 mine operating in the Pittsburgh coal bed. This paper gives an account of the methods used in the investigation, excerpts from the data obtained, and such generalizations as appear to be justified.]

Jan 1, 1937

By R. J. Hundhausen

This report describes the exploration and recent utilization studies the Bureau of Mines conducted on the Iron King, Chambers, and Dry Camp chromite deposits in the John Day district, Grant County, Oreg. The field investigations were undertaken during parts of 1939 and 1942 to determine the tonnage and grade of chromite in the district that could be utilized as a war reserve for the steel industry. As a result of the Bureau's field work, which included construction of 9 miles of access road, 6,204 feet of diamond drilling, 195 channel samples, and 1,020 linear feet of trenching, an ore reserve of 208,000 tons of 22-percent chromic oxide was indicated in the 3 deposits. Less than 1,000 tons of this ore has been mined since the field work was completed because the 2 largest deposits are submarginal in grade and there is as yet no incentive to develop and mine the ore. Since the war, however, the Bureau has been seeking means of utilizing the ore. Two methods of utilization that show promise are direct smelting of the ore in an electric furnace and use of the chromite for making refractory brick.

Jan 1, 1956

By Christopher Mark

The first International Conference on Ground Control in Mining opened with the topic of pillar design. Two classic papers were presented, one by Bieniwski and the other by Wilson. Unfortunately, the two methods were so radically different from each other that it was nearly impossible to reconcile them. Adding to the confusion were the many other pillar strength formulas (such as the Salamon-Munro, the Holland-Gaddy, and the Obert-Duvall, just to name a few) that were also available. Little wonder that discussions of pillar design in those days often ended with anguished cries of “but which formula is the right one?” The past 25 years have seen substantial progress in the science of coal pillar design. Indeed, one testament to the improvement is the relative scarcity of papers on the topic at recent Conferences. Two factors have been largely responsible for the progress that has been made. The first has been the collection of large data bases of actual case histories of pillar performance in a variety of settings, from shallow room-and-pillar mines through deep cover longwalls. These have made possible the development of empirical design procedures that are closely linked to real world experience. The second important factor is the development of sophisticated computer models that can accurately simulate pillar behavior and roof/pillar/floor interactions. Together, these two lines of research have led to a new understanding of pillar mechanics that identifies three modes of pillar failure: • Sudden, massive collapse, accompanied by airblast, for slender pillars (width/height<4) • Squeezing, or slow, non-violent failure, for most room and pillar applications (4<w/h<10) • Entry failure or bumps for deep cover and longwall applications (w/h>10) It is particularly satisfying that the insights gained from numerical models broadly support those obtained from the empirical studies. While far less controversial than in the past, pillar design problems continue to arise. One recent example is pillar design for highwall mining. NIOSH has just released a software package, called ARMPS-HWM, which employs a number of modern pillar design concepts. Since highwall mining web pillars are long and slender, the greatest danger is that of a sudden collapse. ARMPS-HWM suggests two possible prevention strategies, one which

By H. P. Greenwald

[In many coal-mining countries, during he pest decade, there have been made extended studies and accurate measurement of movement of roof strata, tests of the physical properties of specimens cut therefrom, and tests of the strength of end load on artificial supports. Naturally, such studies have been more extensive in European countries, where mining conditions are less favorable than in the United States. As a part of its work in the conservation of coal resource and prevention of accidents in mints, the Bureau of Mines began systematic measurement of the movement of roof strata to in coal mines in the fall of 1935. It was decided that, in the beginning, work on a rapidly retreating rib line in a mechanized mine would give the greatest amount of information in a reasonable time. To this end a cooperative agreement was made with the Pittsburgh Coal Co., Dr. L. E. Young, vice president in charge of operations, for conduct of work in that company&apos;s Montour 10 mine operating in the Pittsburgh coal bed, This paper gives an account of the methods used in the investigation, excerpts from the date obtained, and such generalizations as appear to be justified.]

Jan 1, 1937

By C. L. Karr

Researchers at the U.S. Bureau of Mines (USBM) have developed adaptive process control systems in which genetic algorithms (GA&apos;s) are used to augment fuzzy logic controllers (FLC&apos;s). GA&apos;s are search algorithms that rapidly locate near-optimum solutions to a wide spectrum of problems by loosely modeling the search procedures of natural genetics. FLC&apos;s are rule-based systems that efficiently manipulate a problem environment by modeling the "rule-of-thumb" strategy used in human decision-making. Together, GA&apos;s and FLC&apos;s include all of the capabilities necessary to produce powerful, efficient, and robust adaptive control systems. To perform efficiently, such control systems require a control element to manipulate the problem environment, an analysis element to recognize changes in the problem environment, and an adaptive element to adjust to the changes in the problem environment. The control system also employs a computer simulation of the problem environment. Details of an overall adaptive control system are discussed. A specific laboratory acid-base pH system is used to demonstrate the ideas presented; all results are from the physical laboratory system and not from a computer simulation.

Jan 1, 2010

The objective of this study was two-fold: 1. To perform a world literature search pertinent to the analysis, selection and design of hoisting systems and their components and to codify the search into a literature compendium. The search resulted in a technical data file of over 1500 hard copy items. The compendium index was also suitable for establishing a comprehensive computer-loaded data base on the subject. 2. To develop a comprehensive system of guidelines to cover salient aspects of analysis, selection and design of electrical, mechanical and structural components of a hoisting system with a view to establish parameters for maximum safety and efficiency of operation, installation and revision of the system. 3. Major mechanical components in the hoist and mechanical drive train are considered. Design and specification criteria based on American standards and practices are developed as they apply to typical mine hoist arrangements.

Jan 1, 1988

By W. R. K. Wu

Results of linear correlations of two to four variables by the least-squares method are presented. The variables include 63 parameters representing coal composition, coal plasticity, and coke strength. The composition parameters are on chemical analyses; the plasticity parameters, on three plastometer and dilatometer tests and four miscellaneous tests; and the coke-strength parameters, on three ASTM indices. Seventy-two to eighty-four plastic coals were used in the plasticity and carbonization tests, which together form the basis of this report; 43 nonplastic or weakly plastic coals were used in the coal-band studies. Plots of relations between volatile matter, carbon, and oxygen contents of 1,860 U.S. coals and the 84 coals used are shown. Similar plots between volatile matter and hydrogen or atomic H/C of the 84 coals are also included. Significances of regression coefficient signs for coal composition parameters in the significant correlations found are discussed. Based on these significances, the following relations are shown: (a) coke strength versus average aromaticity, or mineral matter content, of the parent coal; (b) characteristic temperatures of the plastometer and dilatometers, the free-swelling index, or the Gray-King type versus average hydroaromaticity of the coal; and (c) nontemperature parameters of the plastometer and dilatometers versus the physical properties of a certain group of compounds from thermal decomposition of coal. Similarly, significances between the positions of coals in the coal band and the aforementioned relations are also discussed. A structural theory of coal plasticity is proposed. Applications of the correlation results are discussed. Composition parameters, such as carbon, atomic H/C, and calorific value may be used as a basis for selecting coking coals for stronger coke. Plasticity parameters, such as the end temperatures of the plastometer and dilatometers and the free-swelling index, may be used for the same purpose. Based on the best correlations found, coke-strength indices may be estimated to within 4 to 8 units of the observed values; the end temperatures of the plastometer and dilatometer tests, 5° to 10° C.; and the free-swelling index, within 1 unit. Accuracies of all these estimated values are examined, based on the experimental errors of the data involved. Finally, estimations of plasticity parameters from one test with those from others are shown.

Jan 1, 1971

By William M. Knuth

The objectives of this study were the evaluation of the technical and economical feasibility of utilizing color and color infrared aerial photography to satisfy some informational needs for pre-mine planning, mine progress monitoring, and reclamation monitoring. Seven aerial data collection missions were conducted within a two year period over strip mine sites in Pennsylvania. Scales of 1:6,000; 1:12,000; 1:24,000; and 1:48,000 were flown on the first aerial mission. The 1:12,000 was chosen as the optimal scale for the remaining six flights. An extensive literature and legislative review and discussions with strip mine operators identified the informational parameters that could possibly be obtained from aerial photography. Interpretability accuracies were evaluated for parameters in the broad categories of land use, soils, water, vegetation, and geology. Seasonal interpretation characteristics were noted for infrared photography. Man hours for photointerpretation and costs of aerial data collection were monitored closely and incorporated into a cost benefit analysis. Those parameters that could be mapped, identified, or measured with accuracies =75 percent were incorporated into a photointerpretation training manual. An additional analysis was performed to determine the applicability of the interpretation methodologies and results developed for Eastern sites to Western surface coal mining sites. In addition, a separate aerial photographic interpretation manual was produced during this contract. It is intended to be utilized by eastern and midwestern surface mine operators and regulatory personnel.

Jan 1, 1978

By K. L. Paciorek

The primary objective of this program was to determine the toxic fume and fire hazard of materials used in the construction of mine stoppings and in the sealing and reinforcing of mine ribs and roofs. The materials investigated were: silicone, phenolic, and isocyanate-based rigid foams, as well as epoxy and acrylate mine sealants. Of the rigid foams tested, the X-156 urethane foam presented the greatest toxic hazard based on toxic load values hydrogen chloride was the main toxic species evolved by this foam. In &apos;lone of the isocyanate-based compositions was hydrogen cyanide the major component, but its contribution increased with temperature. The FS-24 urethane and Celotex Max-Seal isocyanurate foams had the lowest toxic load values, although these two foams have different applications for in-mine use. Of the two mine sealants tested, the latex /acrylic coating presented the greater toxic hazard with acetic acid being the main toxic species evolved.

Jan 1, 1983

[lllc purpabr at thla report Vd, Lu JeLermlnr the health ar1J sdfet?; Nene11Le a octatc?J ultll Lne oar L.t support Ydlll ..up.I,ated lu dltetllative cupPurt svsLem, larrellLty hcle.g uaeJ af the Len,::rat 1, UI.Jlng 11-al tl. .1 a d 1 c L V h S LIdl&apos;. L dal. I -ten- lu L he tt I .. L&apos;., etuJ I e. 11&apos;? L_1,1&apos;1,11 .Jtd.. it, ..urn,at&apos;l core ,LuJICCill JhLdll, an.: ...,La -IL .utia_tel .an LI?r oar of -l: l,.!rl .a..a. Ma terI.I auJ ...11,mc[Ii -ldla,tutcle 11. LI.ac .uwIttIca Welt a, a.. V.alte,, L.. .:Ltail, ..,,L., uI. LuClu,alug) Lelll anci ur devel?puJ I.,r Cul r1 , all. ...~.,rLrI Vt,ILt 1.&apos;ere ~e,1C L? .Lher Gentiaii m111cc t, UL.-rye a Variety o. a rL vyl I pp.1Ca:t..n:. &apos;a.la IrL ..,_wLeiti, Iapl,.III ,tall ~,..:. IL all, maLertdl c1,arait-erlstIcs, JIRICn,IUIIe. and laden ul1.1 ILc rrgatrelaeuls. ,1 r.? p.&apos;rt .a pro-1Jd, labor rep altrlarnts Jdta and illtlitI ieS tie l,ealtll d?J ,atetV ISSUC ,u-1aled Wit su furl Wall a an, CJl,wttuctSOn, I&apos;aLentiaI appll.at1ou:. Ior support Walt, ,a,. , a, sdV.u,L111 .., u.1 retreating lungval1, single -t r-, roar al,- pi r. [,-+ln, anJ SuhIU..,Ina, Sill] b1OpplllgL ale 1:111neated aid al? e.aIWRac AS Sddemcni LV pre,C&apos;IIL..: .,f LI. Clabllhty r+t rlul,I.,y111I? ulg4,rt .I Le.l,lwlug,. Lr i,,,rCASC Lllc rtCVLLrS rat, u., retrc.+tlnp .unui.,11? ur L., elply, A d v Ctnp IuI-,wall in uer;-!y iy1ng seam, . 11111.a1L .a1,.&apos;iI1.-I,.. nr S.IU1tIVlil a1 milItlI; Lust, La LIldnt;2S L.~ gey support Vait Id tdmcLera la dlaa presents,.]

Jan 1, 1980

By Edward W. Parsons

The transverse force developed by expansion-shell rock-bolt anchors on the wall of a drill hole as the bolt is tensioned was measured by the Bureau of Mines using a device specially designed and fabricated for attachment to a universal testing machine. Load cells equipped with electrical-resistance strain gages provided the data from which the transverse force, in pounds, was calculated. Seven different expansion-shell anchors were tested, and the ratio of transverse force to bolt-tension load was found to range between 0.98 and 1.94 to 1.0. The drag load appeared to be the major cause of the transverse-force variation, but the relative effects of individual factors that affected the ratio between the transverse force and the bolt tension were not determined.

Jan 1, 1968

By Paul M. Tyler

The technology of clay and the manufacture of ceramic products therefrom, and also the clay resources of most of the individual States, are already covered by a voluminous literature. The present resume touches these matters only briefly; its purpose is essentially to bring together in small compass certain of the elementary factors affecting the potential commercial value of a clay deposit. In its preparation the author made extensive use of the annual chapters on Clay in Mineral Resources of the United States and in the two annual issues of the Minerals. Yearbook that succeeded them. For careful review and constructive criticism of the manuscript, the author is indebted to Hewitt Wilson. GENERAL DESCRIPTION The term ?clay? includes a great variety of substances that may differ widely in chemical mineralogical and physical properties. No two clays are exactly alike. All of them however, have the prominent characteristic of becoming more or less plastic when wet. Nearly all of the useful clays can be molded into articles, will hold their shape while being dried, and can be converted into a hard, rocklike substance by heat. Clay may, and in fact usually does, consist of a number of minerals among the commonest of which are kaolinite, quartz, feldspar, iron oxides, mica, bauxite, calcite, and manganese oxides. Organic matter is often present. Pure kaolinite, which has the formula A1203. 2 SiO2. 2H2O, is ordinarily, considered to be the parent "clay substance," butt most clays contain other hydrated mixtures of alumina and silica (aluminosilicic acids) along with indefinite amounts of sand and other nonessential minerals3/ Even, this so-called inert matter affects the plasticity, drying shrinkage, ease of drying, and final density, and at high temperatures may react chemically with the clay substance.

Jan 1, 1929

Underground coal mine tracked vehicles have been studied to determine the state of the art and how brakes might be added to the coal haulage cars. Specific areas of interest are: brake sys terns, couplers, car trucks and car handling procedures. Problems related to adding brakes to the haulage cars appear to be: the limited amount of room to mount the brakes on the cars, brake line connection between rotary dump cars, achieving desirable braking characteristics without over complicating the system and keeping the installation cost to a reasonable figure. This document combines the information contained in the first issue of the "State-of -the-Art of Underground Coal Mine Tracked Vehicle Brake Systems," BRL Report No. 6080, with that contained in a subsequent monthly report.

Jan 1, 1973

By Richard C. Moore

The U.S. Bureau of Mines contracted a study to estimate what effects the underground mining of thick coal seams in the western United Slates would have on the surrounding water resources. Potential coal fields in the western United States where this type of mining might occur were identified. The foreign literature was searched for studies of effects on hydrology from thick seam underground coal mining. Based on the limited information obtained from the foreign literature, estimates of the effects of this type of mining on the ground and surface water in the western states were made.

Jan 1, 1980

By G. L. Neumann

"INTRODUCTION AND SUMMARYThe Guymard mine in Orange County, N. Y., is reported to have been discovered in 1862 and mined until 1876, producing 10,000 tons of lead and zinc ore. 2/The property was examined by an engineer of the Bureau of Mines 3/ in 1948. Development work was done by the Bureau in April and May 1949 and March 1950. During these two periods four drill holes totaling 2,090 feet were completed. The mineralized sections of the core were sampled and assayed.ACKNOWLEDGMENTSThe diamond drilling was conducted under the general supervision of McHenry Mosier, chief, Mining Development Branch, Minerals Technology Division, Region VIII, and the direct supervision of Kenneth M. Earl and the writer as project engineers. Drill cores were logged by Paul K. Sims of the Federal Geological Survey. Chemical analyses were made by the Bruce Williams laboratories, Joplin, Mo., and the Minerals Processing Branch, Minerals Technology Division, Region VIII, Bureau of Mines, under the general supervision of Paul M. Ambrose, chief, and the direct supervision of Howard F. Carl, chief, Physical and Chemical Section.LOCATION AND ACCESSIBILITYThe Guymard deposit (see fig. 1) is on the west slope of Mount Hope, Orange County, N. Y., 1,500 feet northeast of Lake Guymard.Graham station, near the deposit, is on the Erie Railroad about 8 miles north of Port Jervis and 4 miles south of Otisville."

Aug 1, 1952

By Michael J. Beus

This Bureau of Mines report describes a field experiment involving the sinking of two test shafts to directly compare the deformational behavior of circular and rectangular shapes. Results show that the circular shape is less sensitive to geologic discontinuities and applied stress field. Also, the rectangular shape is subject to a variety of behavioral modes, including beam bending and buckling. Geologic discontinuities around circular and rectangular shapes influence displacement significantly. Simple, two-dimensional elastic finite-element modeling, simulating circular and rectangular shapes in a biaxial stress field, shows that the structural response of a shaft is largely controlled by geologic structure. Consideration of anisotropy may be required for realistic analysis of a deep shaft.

Jan 1, 1985

By J. E. Shelton

This presentation covers the results of laboratory studies conducted by the Bureau of Mines Mineral Dressing Section, Northwest Electrodevelopment Laboratory, Albany, Oreg., on alluvial sands from Dismal Swamp, Bear Valley, and Cascade, Idaho. The search for radioactive minerals has led to the reexamination of alluvial deposits; in the process of this reappraisal the frequent presence of minerals bearing columbium and/or tantalum was toted. Because of increased demand for these metals by the defense industries and because these industries depend upon foreign sources for their supply the domestic alluvial black sands are being considered, as a possible domestic source. However, utilization of these alluvial deposits depends upon development of methods of concentrating these valuable minerals. The primary objective of the test work was the study of the effect of attrition scrubbing, sizing, magnetic, electrostatic, and gravity separa¬tion as methods for concentrating and recovering the columbium and tantalum-bearing minerals, samarskite, euxenite, ilmenorutile, and columbite.

Jan 1, 1955

By Eugene H. Skinner

The 7-mile Flathead Tunnel, located in the central Salish Mountains of northwestern Montana, was constructed between 1966 and 1969, With the contract awarded April 19, 1966, drill and blast tunnel excavation began September 30, 1966, and was completed June 21, 1968, in 488 tunnel-driving days, Peak advance was 66 feet per day. On June 27, 1969, all tunnel concrete lining was completed. Average wall and arch concrete placing rates exceeded 1,700 cubic yards daily, with nearly half of the concrete placed during a severe winter season. Major cost savings in concrete tunnel lining were achieved through a value engineering clause in the contract. Achieving consistent results and high rates of placement in concrete lining ranked equal to ground control in overall tunnel problems. Ground control problems exceeded expectations and were of continual concern throughout excavation, One support collapse in the tunnel and one portal slide condition developed during construction. Critical surface geologic exposures were largely obscured; only a portion could be accurately projected underground, An instrumentation program to gather basic data on rock defamation near the heading face for support purposes was a pioneering effort. The Flathead Tunnel was placed in service on November 7, 1970.

Jan 1, 1974

By Will B. Jamison

An ignition detection and suppression system was developed under the scope of this contract. The objective of this machine mounted system was to detect flames caused by frictional sparking from the cutting bits of a continuous mining machine and to suppress it with sufficient speed to prevent the development of an explosion, and to keep the flame from harming the machine operator.

Jan 1, 1976

By S. H. Ash

THIS REPORT covers the second in a series of five projects into which the Conowingo tunnel system has been divided for geographical and practical reasons. It outlines the construction work contemplated-to sink two shafts on the line of the main tunnel that are designated the Nos. 9A and 11 shafts, to turn off from the No. 9A shaft the Lansford and Lykens laterals, and to drive portions of the main tunnel. An emergency pumping plant, consisting of 2 separate pumprooms, each containing 3 horizontal-type centrifugal pumps of 100,000-gallons-per-minute (g. p. m.) capacity, will be constructed at the No. 9A shaft. From the No. 11 shaft will be turned off the Trevorton lateral and portions of the main tunnel, which will connect with the section driven from the No. 9A shaft. Under the proposed project, the Lansford lateral will be driven for a distance of 2 miles, the Lykens lateral for a distance of 10.56 miles, and the Trevorton lateral for a distance of 20 miles. To drive the Lykens and Trevorton laterals for the distance indicated, several construction shafts and slopes must be sunk to permit efficient and safe construction.

Jan 1, 1955