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By Edwin C. Reeder

This is one of a series of papers dealing with mining methods and costs prepared under the sponsorship of end in cooperation with the United States Bureau of Mines. The mining methods described in this paper are those used in one of the large mines producing fluorspar in the Kentucky-Illinois fluorspar field, located in southern Illinois and western Kentucky on the Ohio River. The occurrence of ore and the methods of wining are similar to those in other mines in the district; therefore information regarding methods and the results obtained should be of interest. Improvements in methods have been made as experience developed the need of them. The trine is situated at Rosiclare, Ill., on the Illinois Central Railroad, and shipments are also made b r barge on the Ohio River.

Jan 1, 1930

By D. Harrington

The placing of much, sometimes practically all, of the burden of the expense of mine accidents on the shoulders of the mine operator by compensation laws, and the fact that the problem of protecting the life end limb of workers is now by public opinion largely if not wholly passed to each industry to solve (and present-day thought strongly supports the justice of both of these propositions), are forcing industrial organizations into accident-prevention. Work. This policy is being adopted not alone to protect the companies; in addition, executives alert to their opportunities and obligations are taking part in this work personally to protect themselves. The functions of industrial executives in accident-prevention work are becoming numerous and complex. Executives who are logical in their reasoning, quickly see that before a company can constantly ask or expect the workers to heed safety suggestions, the company and its officials must "put their house in order" by laying down a concrete, definite safety program. For mines this includes primarily adoption of a to a logical mining method, the installation of safe miming equipment and practice the netting forth in definite form (preferably do a printed pamphlet) of the company's minimum safety requirements, and the organization of its operating officials into an accident-prevention body. After the company has its own affairs so arranged that it can go to its workers with "clear, hands" in promoting a safety program, the real work begins; and this is especially applicable in mining.

Jan 1, 1939

By E. P. Youngman

The mining laws referred to by those who furnished the reports mentioned in the preceding paragraph are : General Austrian Mining Law of 1854 and the Law of 1868 , which prescribes for Hungary (as well as for Transylvania ) the full text and decisions of the General Austrian Mining Law; Government Decree 18346 , 1859 ; Parliamentary Decree of 1861 ; the Law of 1871 ; the Commercial Code , Law 37 of 1875 ; the Industrial Lar of 1884 ; the Law of 1386 ; the Decree of the High Court of Justice , 5540 , of 1399 ; Laws 6 and 7 of 1911 ; Law of 1921 ; Laws 23 and 24 of 1922 ; Laws 5 and 21 of 1927 ; and Law 40 of 1928. ( Lev 21 of 1927 and Law 40 of 1928 are labor laws . ) A compilation of the mining laws of Hungary , " Magyar Banya Jog , " or the " Hungarian Mining Law, " was made use of in part . This volume is the second edition of a school textbook , which ras prepared by Dr. Bela Balkay and Dr. Imre Szeoke , and which was published by the Apollo Press ( V. , Sas -utca 13 , Budapest ) in 1909 .

Jun 1, 1931

Remotely monitor overburden response to longwall mining using time domain reflectometry (TDR) and a combination of hardware and software, as part of the U.S. Bureau of Mines (USBM) program to characterize subsidence. Background TDR was developed in the 1960's as a method to locate, discontinuities in coaxial transmission cables. In this method, voltage pulses sent along a cable are reflected by cable defects. The pulse reflections are used to determine the type and magnitude of the defects. The TDR concept was extended to material property measurement by embedding cables into particular materials and evaluating the cable's dielectric behavior as material properties were modified. This technique was adapted by the USBM in 1978 for use in monitoring rock movement during underground mining. The same concept is utilized today. A coaxial cable is grouted into a rock mass that is expected to deform. Progressive rock movement causes the cable to deform, as shown in figure 1, and changes to occur in the cable's electrical properties, which then produce changes in TDR reflection signatures. The technology has advanced to the point where it is now possible to distinguish shear deformation from tensile deformation and to quantify rock mass displacements by analyzing the TDR signatures.

Jan 1, 1995

By George S. Rice

There have appeared, from time to time, comparisons of various features of coal mining practice in the United States and Great Britain. A recent, article, appearing in a British journal, points out that the American miner produces 3 1/2 times as much coal per shift as the miner, at one-half the cost, and proceeds to explain the natural industrial, and engineering causes which lead to this result. Amon« he reasons advanced. is that the American coal miner enjoys the advantage of more easily worked seams of coal, due to the fact that the coal mining industry in the United States is of more recent date than in Great Britain. The latter qualification is not correct, because where these advantages exist, they will persist. The coal beds of the United States are not buried deeply, except in the remote parts of the country, as in the Uinta Basin of Utah. The article referred to states that many of our miners are still employed on out seams reached by "adits", (which we term entries), or by vertical shafts of moderate depth. It is probable in fact that the great bulk of the coal of the United States is taken out from a depth of less than 400 feet.

Mar 1, 1920

By David S. Yantek

A-weighted sound levels around vibrating screens in coal preparation plants often exceed 90 dB(A). The National Institute for Occupational Safety and Health (NIOSH) is actively developing noise controls to reduce noise generated by horizontal vibrating screens. A 121-microphone, 3.5-meter-diameter array was used to perform beamforming to determine locations of significant noise radiation on the screen. Below about 1 kHz, the screen body was found to be the most significant noise source. The beamforming contour maps showed several key locations on the sides of the screen and the feedbox are the most significant contributors. Operating deflection shape (ODS) analysis was used to examine the screen behavior under actual operating conditions. This information is helpful in determining how to modify the screen body to reduce the noise radiated by the screen below 1 kHz. The analysis showed modal vibration patterns on the sides and feed box were the main contributors to noise. The results show several areas on the screen sides and feedbox that can be modified to reduce noise.

Jan 1, 2009

By R. R. Sayers, W. J. McConnell

"The health, comfort, and efficiency of men engaged in the mining industry may be impaired, in some instances very seriously, by abnormal physical conditions of the mine air or by variations in its composition. This is true in some of sheet metal mines of the West where high temperatures with varying humidities are encountered. Physiological studies have been made in some of these mines showing the effects of various temperatures end humidities. As it is difficult to carry out studies on many controlled temperatures, it was thought best to make the experiments in a laboratory and apply the results to the industry insofar as practicableThe effects of moderately high temperatures and humidities are more difficult to measure perhaps than the extreme conditions, but may be predisposing causes of fatigue, discomfort and disease, A cooperative study of the physioloical effects of heat and humidity is being conducted by the Bureau of Mines and the U. S. Public Health Service cooperative with the American Society of Heating and Ventilating Engineers, in the Research Laboratory of the Bureau of Mines at Pittsburgh, Pa."

Mar 1, 1924

By John Nagy, Austin R. Cooper

Information is presented on the pressure and rate of pressure development during a dust explosion . The data were obtained in laboratory studies in a 75- cubic inch vessel with mineral , agricultural and chemical dusts . The factors investigated include dust concentration , oxygen concentration of the atmosphere , admixed inert powder , and admixed moisture . Information is given also on the effects of these factors on the composition of the atmosphere after the explosion .

Jan 1, 1964

By Allan F. Smith

The Bureau of Mines studied toxic products produced by burning eight fire-resistant mines conveyor belts, a brattice cloth, and an electrical cable insulation obtained from laboratory-scale burning experiments under various air-flow conditions. Generally, CO product concentrations for most materials were noticeably higher then the NO2 and HC1 levels that were measured; also, no phosgene was detected. However, several of the fire-resistant belt samples yielded HC1 concentrations that were above the reported lethal level for 1/2 to 1-hour exposures, although these data were limited to flow conditions where air dilution effects were small; the belt materials that showed this behavior included samples of polyvinyl chloride, styrene butadiene, styrene butadiene blends, and a British neoprene which yielded the greatest amount of toxic vapor. In addition, some results are presented on the phosphoric acid concentrations that may be produced from the decomposition of ammonium dihydrogen phosphate when dispersed on a burning coalbed.

Jan 1, 1973

By R. Hogg, E. Kaya

"The presence of agglomerated particles in airborne dust in coal mines has been confirmed by SEM examination of static samples collected on substrates. In addition, the effect of agglomerated particles on the performance of cascade impactors and cyclone-type personal samplers has been studied. Simple procedures have been developed for evaluating the extent of agglomeration in air-borne dust by comparing the observed size-selectivity of the sampling devices with that expected under idealized conditions. Applications of these techniques in the laboratory and in underground mines are discussed.INTRODUCTIONAirborne dust is invariably present in mine atmospheres. Particle size is a primary factor in determining the behavior of the dust, its effects on miners' health and the effectiveness of dust control measures. Obviously, agglomeration of the dust particles can have important effects on: ""natural"" dust removal processes such as settling• the use of water sprays etc., for dust control• pulmonary deposition characteristicsIn addition, the presence of agglomerates could influence the effective toxicity of the dust. For example, ultrafine particles are often thought to be relatively unimportant in the development of respiratory ailments because of their low deposition efficiency. However, the latter could be substantially increased if such particles were present in larger agglomerates. It is by no means obvious that there should be significant agglomeration of the airborne dust in a mine atmosphere. In fact, calculations based on the classical coagulation theories indicate that, at the kinds of dust concentrations that exist even in what would be regarded as “very dusty"" atmospheres, the coagulation half-time* .should be of the order of weeks or even months. On this basis, agglomeration would be expected to be essentially negligible. On the other hand, laboratory experiments (Polat et al., 1991) have revealed very extensive agglomeration in the airborne dust released during the crushing of individual coal and mineral particles. It is postulated that such agglomeration occurs immediately at the point of dust generation. In other words, many of the fine fragments produced on fracture are never completely separated from their neighbors."

Mar 1, 1992

By Roger J. Morrell

The Bureau of Mines conducted drag cutting experiments in hard, abrasive rock in an effort to extend the capabilities of an experimental kerf-core mining machine. The basic kerf-core mining machine cannot be used in hard, abrasive rocks because of the high wear experienced by the kerf cutters. These experiments were conducted in an effort to develop a method of preweakening the rock ahead of the kerf cutters in order to reduce the high cutting loads and hence the higher wear rates experienced by the cutters. The two "preweakening" techniques studied were indenting with mechanical wedges and single and double slotting with diamond saws. The best cutter force reduction achieved with mechanical indenting as 70 pct, whereas double slotting achieved force reductions of up to 99 pct. Conceptual designs of preweakening systems that could be retrofitted onto the basic kerfing cutterhead were developed for both the indenting and the slotting techniques. A high-energy impactor with wedge bit was used for the indenting method, and high-pressure water jets were used for the slotting method. A preliminary technical and economic analysis was performed for both of these full-scale systems to illustrate the methodology and to point out the important technical and economic factors that must be considered.

Jan 1, 1987

Decrease dust concentra¬tions of longwall face workers by keeping them up¬wind of the headgate stage loader and crusher. Approach Direct the face airflow from tailgate-to-headgate, the direction of coal transport. How It Works Ventilation is the primary method of dust control on longwall faces, and the most effective ventilation control is to put workers upwind of dust sources. Recent ad¬vances in longwall dust sampling by the Bureau have shown that on some faces, the headgate crusher and transfer points are signifi¬cant sources of dust -some¬times making up more than half of the total dust to which the face workers are exposed. Also, when the air is coursed from head-to-tail, the relative velocity between the air and moving coal on the face conveyor can cause dust entrainment from the conveyor, particularly if the coal is dry. On the faces where these dust sources are a signifi¬cant problem, they may be eliminated by coursing the air from tailgate-to-headgate, provided that the mine roof is stable enough to permit the necessary intake of the tailgate along with an aux¬iliary intake at the headgate.

Jan 1, 1982

Determine what diameter piping is necessary to obtain sufficient water flow to spray nozzles used for dust suppression. Approach A simplified, diagrammatic method of calculating the flow of water through a proposed system consisting of a supply line and two banks of spray nuzzles is outlined. How It Works The pressure versus flowrate of the supply at the tapping point must be known or measured. The supply curve of typical city water at a 1 ¼ -inch pipe outlet is shown by the lowest curve in Figure 1. A supply curve for a typical pump fed from an open sump is shown by the middle curve. The combination of these, the supply curve of a pump fed by the city water supply is shown by adding the lower two curves to get the upper curve. A pump supply curve showing flowrate versus pressure is usually supplied by the manufacturer. The water supply line flow curve can be determined by measuring the time required to fill a 55 gallon barrel at various valve settings to determine flow, and by measuring corresponding pressures at the valve with a gauge.

Jan 1, 1979

By Guy A. Johnson

Despite the use of warning alarms to alert miners to the backward movement of large mining equipment, miners still are injured too frequently in backup accidents. Currently approved backup alarm technology consists of continuous sounding alarm systems. New technology has developed a warning system that initiates an alarm only if there is an object close behind the vehicle. This advancement eliminates constant exposure to the alarm because a warning is given only in case of a potential collision. Adoption of this development can improve safety and reduce damage, especially for front-end loaders (FEL's). It will also eliminate a source of nuisance noise in urban and residential areas. This Bureau of Mines report describes the general characteristics of infrared (IR) light, ultrasonic wave, and Doppler radar technology as used for backup alarms, and reviews the testing of the most promising detection devices.

Jan 1, 1986

By D. Harrington

In general, mining is carried on underground, that is, in confined places where it is difficult to obtain adequate lighting and frequently in rock strata requiring much care to prevent caving. Moreover, explosives must be used in mining with the numerous hazards associated with them, and some mines give off explosive or irrespirable gases; also, ma- chinery must be used, usually under conditions much more hazardous than on the surface. These and many other considerations cause mining to be probably the most hazardous occupation in which large numbers of our fellow countrymen are employed. Prevention of accidents in the mining industry is far more complicated than in surface industrial work, even of the more hazardous types, because the different elements that enter into possible accident occurrence are ascertained more readily above ground and suitable action can be taken against them; moreover, errors in connection with prevention of accidents in surface industrial work usually affect only one or, possibly, a few persons, while in zines one human error may readily cause an explosion or other untoward occurrence resulting in the death of scores or even hundreds of persons. This difficulty in the prevention of accidents in and around mines is well-known, and most countries and States have regulations to guard the safety and, to a much smaller extent, the health of workers in mining and allied industries. In general, the State laws and regu- lations regarding the welfare of mine workers are merely a skeletonized outline of some more or less fundamental minimum requirements and are far too general to do much more than suggest some procedure which may or may not be safe or healthful. Most of them are grotesquely out-of-date as applied to present-day conditions, and none of them is adequate to protect life, limb, health, or property. Unquestionably, there is great need for a closer correlation of the laws and regulations of the various States with regard to safety in the mining and allied industries, and while mining conditions vary far too much for a standardized mine safety law applicable to all of the States, on the other hand there are numerous standard and fairly fundamental safety pro- visions which apply to all mines and which should be embodied in the mining codes of all States. Undoubtedly, these standardized safety requirements would be opposed by a consider- able part of the industry, but the ultimate effect would be beneficial to the owners, work- ers, and the general public. For many years progressive mining companies in the United States have not been satisfied to operate only within the meager safety requirements of the State laws or regulations and have adopted additional and far more effective safety procedure of their own, although com- plying also with the State laws and regulations. As a result of this forward-locking policy, zany of these companies have made astonishing progress in the reduction of accidents.

Dec 1, 1935

By E. P. Youngman

This paper is one of a series of digests of foreign minim legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the minim lams of Ceylon has been prey tired from the best available information in Washington and is released subject to amplification and correction, if necessary, by United States foreign-service officers. INTRODUCTION Ceylon has no basic mining law; the general rules governing the granting of mineral concessions and affecting legal titles of concessionaires are laid down in Ceylon Government ordinances or are found in the authorized forms for licenses and leases. The material available in the preparation of this digest is as follows:

Jan 1, 1933

By W. J. Fene

It is often desired to obtain samples of air in places where collection by ordinary methods is not feasible, as in shafts amore means of descent or ascent are not provided, in sewer manholes, in gas or water wells, in empty oil tanks, and in sealed areas in mines. Heretofore, when such sampling was required, it was necessary to utilize the aspirating method, which was not always satisfactory; and to obtain samples of air in deep shafts, it was necessary to use long sections of rubber tubing, which was not always available. DESCRIPTION OF NEW DEVICE A new method or "device" employs a common snap-type mousetrap to break the neck of a vacuum tube at the place where it is desired to collect the sample (see fig. 1). A mousetrap is mounted on one end of a block of wood 11-3/4 by 3 by 3/4 inches in such camper that a lead weight attached to the trigger hall spring the trap when the device is given a sharp jerk. A vacuum tube is placed on the other end of the block and held in place by a strong rubber band. A strip of corrugated rubber is placed on each side of the grooved block to prevent the tube from clipping when the sample is taken. An adjustable shoulder, provided with a rubber cap, is pieced se that the neck of the vacuum tube will rest on it. The shoulder is made adjustable to accommodate various sizes of tubas and to keep the neck of the tube from breaking tee far back from the point. A metal handle is fastened to one end of the block, with a hole in the end through which the brass wire used for lowering the device is tied. The device is enclosed by a strong wire-gauge covering, hinged on one side and so arranged that it can be locked shut on the other side. This covering prevent: breaking of the tube while it is being lowered or raised in a shaft or other place. Brass wire of not less than 22 gage should be used for lowering the device. A detailed drawing of the device is shown in figure 2.

Jan 1, 1940

By Gerald T. Homce, Michael R. Yenchek, H. Kenneth Sacks, James C. Cawley

Accidents occur when least expected, from sources that we rarely anticipate and with outcomes that can vary greatly. Anyone who has ever been involved in an automobile accident knows, the transition from driving comfortably and safely down a highway to being involved in a potentially life-threatening situation can occur in a heartbeat. Accidents on the job are no different. The mining industry has a relatively small number of electrical injuries, compared to industries such as construction or agriculture, due to the small total employment in mining. Mining does, however, have one of the highest occupational electrocution rates of any U.S. industry, at 2.8 for every 100,000 workers per year. This is approximately four times the average for all industries. Data from the Mine Safety and Health Administration (MSHA) shows that 75 electrical fatalities occurred in the mining industry between 1990 and 1999. Of these, at least 17% involved high-reaching mobile equipment that contacted overhead power lines.

By L. D. Gehi, A. W. Khair, M. Ahmad

"Bit wear presents problems to mining operations because it affects both productivity and economics. Most bit research deals with energy requirements and energy dissipation mechanics for ideal fragmentation during the cutting process.Mechanical cutting leads to dust generation. Past studies involving dust generation due to bit wear concluded that dust concentrations increased considerably after a 7% bit weight loss: leading researchers recommend that the bits be changed at that point.Bit wear is affected by three factors: machine operating parameters in-situ mining conditions and rock properties. Operating parameters such as the depth of cut tool material spray position and the drum's rotating velocity are very important and have a definite impact on bit wear.During the mining process the amount of rock in coal and the strength of that rock is important as abrasion and adhesion take affect. Diffusive wear or deformation becomes dominant only when the temperatures exceed critical. Temperatures rise as a function of drum velocity rock properties and the cutting tool itself.Miner bit surveyIn this study, 15 mines were surveyed, and of those six responded for nine seams. The survey reflected a wide range of information about coal production and bit consumption from continuous miner sections. Also used bits were collected to get first-hand information to analyze wear."

Nov 1, 1995

By H. H. Schrenk

[A colorimetric method5/ for the determination of benzene in amounts as low as 0.001 mg has been developed recently at the U.S. Bureau of Mines Pittsburgh Experiment Station by the authors, with the assistance of chemical personnel fro a the Allegheny County (Pa.) Relief Works Division. The method is based on the direct nitration of either liquid - or gas - phase benzene, followed by neutralization, extraction with butanone, and final treatment with sodium hydroxide which produces a violet color. The color is matched with color standards of known values. Although the method is adaptable to many conditions the primary objective was a procedure that would be suitable for hygienic investigations. The development worth included a study of possible interference by chemicals that be present in those situations in which the method. would be employed. In this study it was found that a specimen of hexane prepared by the Gulf Research Laboratory, Pittsburgh, by fractionation of West Virginia natural gas gave positive result for benzene, whereas a specimen of pentane prepared in the same manner showed only a trace, and specimens of n -heptane and octane (2,2,4 trimethylpentane) supplied by Eastman Kodak Co. save a negative result. According to information obtained from the Eastman Kodak Co. the latter two compounds were highly purified, the n-heptene being prepared from line and the octane synthesized in the laboratory. On nitration of a larger amount of tae natural hexane a visible quantity, of needlelike crystals which resembled those of m-dinitrobenzene was obtained. The hexane from this nitration was recovered by distillation and again nitrated, but no crystals or colorimetric indication of benzene was obtained. This imitated that the specimen of natural hexane contained a substance which at least had the chemical behavior of benzene.]

Jan 1, 1935