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By F. S. Crawford

Companies which have been engaged in safety work for a number of years are becoming increasingly aware of the fact that it is not enough to supply guards for various pieces of machinery and equipment and to supply safety inspection to see that rules are being carried out. Studies of many safety organizations have demonstrated that the accidents which could have been prevented by proper guards constitute only a small percentage of the total acci- dents, and amount to perhaps not more than 15 per cent. Evidently, if success is to be attained in preventing all accidents which it is humanly possible to prevent, a company must have the cooperation of every employee. Mining particularly presents probably the greatest hazards of any industry. Prevention of accidents. is made increasingly difficult because men often work alone, although generally in pairs, and only in the concentrated systems of mining do they usually work in groups of more than three or four. Supervision is difficult, therefore, and much reliance must be placed upon the individual workmen. In mining, as perhaps in no other occupation, it is of the greatest importance that individual workmen should receive continuous safety education. Within the last few years safety education has come to the front as one of the most important of accident-prevention measures, although it is true that its importance has been repeatedly stressed by the United States Bureau of Mines and other national safety organizations since the inception of the safety movement many years ago. A review of the safety educational methods of some companies in the Lake Superior district should be of interest. Perhaps better methods are in use in other parts of the country, but the methods shown have been instrumental in many cases in reducing the number of accidents. In one mine in the district whose methods are described the frequency of accidents has been reduced to zero within the last two years. A number of other mines in the district have recently gone into the class having no lost-time accidents for considerable periods of time. One company in the Lake Superior region, operating over 30 mines, succeeded during one month of 1930 in operating every mine without having a single accident which caused lost time beyond the day of the injury. Records like these are increasing in number, and while it is believed that they are the combined result of different means of safety activity, it is undoubtedly true that many of these results were obtained through safety educational methods.

Sep 1, 1931

By R. C. Buehl

[Improvements in refractories for high-temperature service have made possible the use of higher temperature in many processes. Consequently, it sometimes is desirable to use gases heated above 1,600° F., and for moderate rates of gas flow, there gases can be heaters best with pebble heaters. Pebble heaters of the stationary-bed type in which the chanber was lined with mullite brick and pebbles of pure alumina served as the heat-exchange medium have been used recently to heat the air blown into an experimental blast furnace4/ These pebble heaters worked well and made it possible to use air temperature up to 2,500° F. at the tuyere of the furnace. Since little has been published on this type of gas heater, a review of the construction on employed and operating data should assist in selecting applications and designing units.]

Jan 1, 1953

By George S. Scott

The Bureau of Mines conducted ignition, flammability, and decomposition experiments on gas mixtures containing ethylene to determine its flammability characteristics at elevated pressures and ambient temperatures. Pure ethylene was found to propagate a decomposition reaction at 1,000 psig and ambient temperatures when ignited with 1 gram or more of guncotton in a 2-inch-id bomb. The decomposition products were primarily carbon, methane, and hydrogen.

Jan 1, 1965

By Charles E. Munroe

On March 14, 1921, an explosion occurred at about 6:15 A.~. on the premises of an iron-mining concern throug:1 which two magazines, one containing upwards of 9,000 pounds ot a high explosive of the dynamite class, and a second, 60 feet distant, containing upwards of 10,000 No. 6 detonators, were completely destroyed, and a ncratertt,? f3et deep by 30 feet in diameter, was excavated in the gro~ at ~he place whare the mag~iine containing the high explosive had been lo~ated. As a rule any eye wit~esses to the circumstances im.~ediataly preceding and d(irectly concurrent with a.c.ci.:lental ex;losions ar.e victims of s11ch explosions, and, therefore, the conclusions reached as to the cauoa. of such explosions must, perf'orce, be based aln:ost completely on circumstantial evidetJ.ce. In this iii.stance, b:ecause both the explosive and detonators were of -orov{:;d: character; because of the time of the day and the state of operations iit the·· time of the e:.q,losion; because the rerroteness of the location of the n:-1agazi::1es 1 0::1 the side of a ravine, easily admittfi of unobserved approach; beca:iise differencas existed, and because no obvious cause was at once apparent, there arose suspicfon that the explosion was not accidental.

Sep 1, 1921

By Oliver Q. Leone

The effect of oxygen content in the anode metal on titanium electrorefining characteristics was studied. Increasing quantities of oxygen in the anode resulted in increased anode scale formation, decreased anode and cathode current efficiencies, lower titanium recovery efficiencies, and higher oxygen content of the cathode products. The titanium electrorefining process performed best when the anodes did not contain more than 0.5 percent oxygen, although anode dissolution was recorded for alloys containing up to 25 percent oxygen. Back emf affords a useful index of an alloy to electrorefining.

Jan 1, 1965

By J. O. Lewis

"The significant facts in the problem of the relation between the production of crude petroleum, and the ever-increasing demand for petroleum products are that in spite of continually increasing production, improvements in methods of refining and utilization, and heavy increases in imports, demands grow still more rapidly and we seem always faced with a shortage at hand or lust ahead. On the other hand, our foremost authorities warn um of entirely inadequate domestic reserves. Looking abroad we find some large fields and many of speculative promise, 'tut the situation is complicated by international relations and demands by other countries which promise to be even more insistent than oars. This is the situation, then. We can not rely upon our own Crude Petroleum to meet the Ever Increasing Demand for Petroleum Products.I wish to follow this somewhat alarming statement by saying at once that the Bureau of Mines is not pessimistic in facing this situation. To my mind those who discuss the oil situation may be placed in three categories; the pessimists, the optimists, and the super-optimists. The pessimists I call those who see darkly and will concede no possibility of solution. According to them a few years will see the automobiles piled in windrows of 'dilapidated junk, I have no sympathy with this point of view and deem it vicious and entirely unwarranted.The optimists I term those who believe that there is a solution and that we shall be able to meet all of our reasonable requirements for as far into the future as can be foreseen, yet who recognizes that this desired end can not be attained without prevision and energetic effort.The super-optimists are those who will say to you, ""There is nothing to this talk of shortage, whenever we have needed oil we have always found it and always will."" To these gentlemen the possibility of an inadequate supply of oil is as incomprehensible as the possibility of the extinction of the passenger pigeon was to the early settlers who saw flocks that hid the sun for days during their passage. The passenger pigeon disappeared within two generations thereafter, and I deem this point of view as being perhaps more vicious than that of the extreme pessimist. It seems to me it is nothing less than improvidence lulling us into a false sense of security. There is an old proverb to the effect that ""The Lord helps him who helps himself."" I believe that we shall solve the oil problem, but I do not think it will be solved by vague optimism. It is going to call for our most energetic efforts and I believe we shall have to do a lot of ""helping ourselves."""

Oct 1, 1920

By R. C. Ellman

Significant effects of in-the-mill drying on the pulverization of lignite have been demonstrated in an experimental impact-type pulverizer by tests in which the primary variable was temperature of the sweeping gas. Reduced power requirements and increased product fineness were observed as the extent of drying was increased. Pulverization with in-the-mill drying was studied in comparative tests made on lignites from five mine sources. All of the lignites responded in a similar manner; however, differences in the pulverizing characteristics of the individual lignites were significant. For one lignite, the electrical input to the pulverizer driving motor with minimum sweeping-gas temperature was 33.9 kw.-hr. per ton, decreasing to 14.0 kw.-hr. per ton with a sweeping-gas temperature of 658° F.; for another lignite, at comparable operating conditions, the electrical input decreased from 59.1 to 19.0 kw.-hr. per ton. In the first case, the product fineness increased with increasing temperature of sweeping gas from 65.2 to 79.2 percent through a 200-mesh sieve, and in the second case, from b2.7 to 86.9 percent through a 200-mesh sieve.

Jan 1, 1962

By E. D. Eastman

The recent determination by Eckman and Rossini of the heat of formation of sulphur dioxide appears to be of much greater accuracy than any previous measurement . The value obtained by them , 70,940 cal . , is in good agreement with that of Thomsen ( 71,080 ) , but differs by about 1,700 calories from Berthelot's result ( 69,260 ) , and by 1,940 calories from the provisional figure ( 69,000 ) adopted by Lewis and Randall in their studies of the free energies of the sulphur compounds . This large discrepancy suggested the desirability of a recalculation of the free energy of sulphur dioxide . In addition it is now possiblt to fix the specific heat of S₂ gas with greater certainty than at the time of the original calculations . These two changes are incorporated in the recalculations described below , and directly affect the values of AH , and the Ar terms in the free energy equation . In the determination of the integration constant of the latter equation , the free energies and specific heats of water vapor and the oxides of carbon are required as auxiliary data . In this work these are based , with certain exceptions , upon the equations previously deduced , which differ appreciably from the corresponding equations of Lewis and Randall . 56 · The principal equilibria employed below , and the plan of calculation , remain the same as in the calculations of Lewis and Randall . Before beginning this revision a search of the literature was made , extending to August , 1930 , for studies of additional equilibria . Only one reaction was found that gives promise of increased accuracy . This is the equilibrium of sulphur dioxide with copper , cuprous oxide , and cuprous sulphide . In this case , however , certain of the subsidiary data are lacking , and until they become available , the existing studies of the equilibrium in this system can not be successfully utilized . The changes in the numerical data mentioned above , especially in the thermochemical constants , are therefore solely responsible for the rather significant differences of the revised from the original values of the free energy .

Apr 1, 1931

By Jacqueline A. McClaskey

The U.S. Bureau of Mines (USBM) Information and Analysis Directorate collects worldwide data on virtually every commercially important non fuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U. S. economy. The USBM's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority for the USBM survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96-479, 96th Congress). This act strengthens protection for proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1992

By J. H. Perry

The Bureau of Mines is conducting research to determine the effectiveness of long holes in degasifying an area of the Upper Split of the Lower Sunnyside coalbed at Kaiser Steel Co.'s Sunnyside No.1 mine. These holes were drilled from the two outside entries of a section that was closed to mining because of excessive methane emissions. Two holes drilled to 430 and 450 feet produced initial gas flows of 160,000 and 127,000 cfd, respectively. Sixteen days after the completion of the second hole, the total gas production declined to just over 144,000 cfd. In 9 months of degasification, over 35 MMcf of commercial-quality gas has been removed from the coalbed. The combined gas flows declined to 106,000 cfd in the 9-month period. The two holes have reduced face emissions by about 40 pet.

Jan 1, 1978

By J. H. Perry, Joseph Cervik, G. N. Aul

The Bureau of Mines is conducting research to determine the effectiveness of long holes in degasifying an area of the Upper Split of the Lower Sunnyside coalbed at Kaiser Steel CO.'s Sunnyside No. 1 mine. These holes were drilled from the two outside entries of a section that was closed to mining because of excessive methane emissions. Two holes drilled to 430 and 450 feet produced initial gas flows of 160,000 and 127,000 cfd, respectively. Sixteen days after the completion of the second hole, the total gas production declined to just over 144,000 cfd. In 9 months of degasification, over 35 MMcf of commercial-quality gas has been removed from the coalbed. The combined gas flows declined to 106,000 cfd in the 9-month period. The two holes have reduced face emissions by about 40 pct.

Jan 1, 1978

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

APPENDIX A - PNEUMATIC TRANSPORT OF FLY ASH 1. Introduction Two types of pneumatic transport of fly ash are critical to the success of (1) Transport of fly ash from the fly ash truck to the entrance to the borehole. Depending on the surface topography, this may be horizontal, decential and ascential. (2) Vertical downflow of fly ash through the borehole. All fly ash trucks have limited pressure with which they can pump the fly ash. Thus, the pressure drop in the fly ash hose will define the maximum length for pumping and consequently the maximum distance that the fly ash truck can be parked from the auxiliary blower. The same relationships describe the flow of the dilute fly ash-air mixture produced by mixing with the auxiliary air from the blower and thus define the selection of the pipe diameter. These are im¬portant considerations in the proper selection of the location of the passages to be sealed and the type of surface preparation required. The flow characteristics of fly ash down the borehole determine the selection of the minimum borehole diameter and the blower pressure. This appendix presents theoretical analyses of these flow regimes and summarizes the limited experimental data obtained during the field tests at Grant Town, described in Section 8.4. The analysis for the borehole flow is presented first as it is of greater interest to the program. This is followed by a discussion of the horizontal flow.

Jan 1, 1973

By E. P. Youngman

Gold and precious stones were mined in Egypt in prehistoric times. This mining, carried on at intervals, extended over thousands of years, until about 1300 A. D. Then ensued a dormant period of several hundred yoars. In the mean- time Europe made great rogress in mining practice, metallurgy, and geology and sent out various expeditions during the nineteenth century to investigate ancient mines. But the exploratory work produced no material results, and not until the beginning of the present century did actual mining recommence. The reopening of old gold mines in Rhodesia aroused interest in London and Paris, and these cities provided the capital necessary for the investigation of the ancient minee in West Africa and Egypt. Speculation resulted in the division of most of the uncultivated area of Egypt and the Sudan into huge concessions, and a number of expeditions were made; but after an unprecedented activity in West Africa, roaction set in, and the flow of capital ceased. The concession- aires, mostly individuals with insufficient capital and with a misconception of the initial difficulties of communication, water supply, and labor, allowed

Jan 1, 1932

By Michael J. Sapko, Gregory M. Green, Harry C. Verakis, Kenneth L. Cashdollar

The National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) conducted a joint survey to determine the range of coal particle sizes found in dust samples collected from intake airways of U.S. coal mines. The last comprehensive survey of this type was performed in the 1920’s. The size of the coal dust is relevant to the amount of rock dust required to inert the coal dust, with more rock dust needed to inert finer sizes of coal dust. Dust samples were collected by MSHA inspectors from several mines in each of MSHA’s ten bituminous Coal Mine Health and Safety Districts. Samples were normally collected in several intakes at each mine. The laboratory analysis procedures included acid leaching of the sample to remove the limestone rock dust, sonic sieving to determine the dust size, and low temperature ashing of the sieved fractions to correct for any remaining incombustible matter. The results indicate that particle sizes of mine coal dust in intake airways are finer than those measured in the 1920’s. The significance of these finer coal dust sizes is discussed relevant to the amount of rock dust required to prevent coal dust explosions.

Although early Spanish settlers used coal several centuries ago, significant commercial coal mining in New Mexico began in 1861, when the U.S. Army opened a mine to supply Fort Craig. Since then, coal from the state has been used to fuel railroads, lead and copper smelters, and other local industry. In recent years, lower-cost strip mining methods and an increased demand for coal by electric utilities in the Southwest have caused an increase in New Mexico coal production. The coal-bearing regions of New Mexico underlie about 25,000 square miles or20.6 percent of the total area of the state. However, the majority of coal-bearing regions lie under Indian lands that are regulated by the Office of Surface Mining (see Navajo and Hopi data on pages 72-75). Today, most of the coal produced in New Mexico comes from the San Juan Basin in the northwest part of the state and the Raton Area in the north central part. New Mexico's reserves are estimated to be 4.6 billion tons, about one percent of the national reserve. New Mexico's permanent regulatory program was conditionally approved December 3 1, 1980. Its Abandoned Mine Lands Program was approved July 17,198 1.

Jan 1, 1992

By W. S. Sanner

Grinding experiments were conducted to determine the finest anthracite particles that could be produced in a ball mill. Continuous and batch tests were run in a dry-grinding ball mill. Batch grinding produced the finest coal particles. They averaged 2.2 microns in diameter and were 99.0 percent smaller than 37 microns. Continuous grinding yielded a product 6.1 microns in diameter, with 96 percent smaller than 37 microns.

Jan 1, 1968

By Will H. Coghill

Titanium is a well-known component of bauxite ores, sometimes occurring in sufficient quantity to mace its recovery worth considering. This question has been raised by some of the companies lixiviating bauxite ores. At the East St. Louis plant of the Aluminum Ore Co., a subsidiary of the Aluminum Co. of America, the waste sludge discharged daily contains over 75,000 pounds of Ti02. The sludge is all through 20-mesh, and a large proportion is slime. A supple of the waste was deslimed so that a gravity-concentration test of the "sand" could be made. The Aluminum Ore Co. cooperated in the work and made the chemical determinations In order to anticipate the results of table concentration a series of specific gravity fractions (float-and-sink) was made with heavy liquids. Acetylene tetrabromide was used for a density of 2.95, methylene iodide for 3.33, and thallium formate for 3.78, and the double salt of thallium formate-malonate made the separation at slimed sample appears in Table 1.

Jan 1, 1928

By L. L. NAUS, R. D. Currie

Hazards in connection with the use of compressed-air jets for ventilating gassy mines are given little consideration by most mine officials largely because compressed air is considered the safest means of transmitting power for operating various types of mining machinery, and the inherent dangers in its use for this purpose are virtually negligible . The installation of compressed-air lines in coal mines leads to the utilization of compressed air for ventilating working places , with the result that , although the primary ventilation systems may be adequate to meet existing needs , proper conduction of normal ventilation has been neglected , so the working faces receive only a small amount ofthe total air circulated through the mine . Reliance in part on compressed air or other auxiliary means for ventilation is always attended by danger that gas will accumulate , due to intermittent operation , and the tendency is to operate auxiliary schemes only. during the working shift ( or possibly only part of the shift ) and to dispense with them during off- shifts or at times during the working shift when gas may accumulate because of lack of ventilation . When the men come on shift the auxiliary ventilating device often may be started without a preliminary examination of the working place , or .. the examination may be made sometime before the oncoming shift arrives , the gas being allowed to accumulate in the meantime. This may result in uncontrolled movement of a body of gas if proper precautions are not taken . Several mine explosions have been caused by the movement of a known body of gas by compressed air into the haulageway, where it was ignited by an arc from a passing locomotive . This danger is more pronounced where supervision is lax .

Aug 1, 1937

By John R. Bartels, Dean H. Ambrose, Richard C. Wang

This paper presents the results of a study to verify and validate a computer model that represents and analyzes motions and hazardous events in a simulated three dimensional workplace. The purpose of the computer model is to support research that is investigating the safe speed range for the vertical movement of roof bolter boom arms to reduce worker injuries in underground coal mines. The information obtained for this paper is based upon a project that is investigating means to reduce workers risks of injury from exposure to mining machinery. The methodology being employed by the project includes human factors design considerations, anthropometric modeling and simulation tools, laboratory validation, engineering interventions, and collaboration with industry and an equipment manufacturer. The results of this study were used to (1) determine the input parameters that are unique to the mining environment and needed to develop a credible, computer-based, human-machine interactive model, (2) develop test methods to measure the required parameters, and (3) to refine the human-machine interactive computer model.

By Robert L. Chufo

This paper describes a general purpose imaging technology developed by the U.S. Bureau of Mines (USBM) that, when fully implemented, will solve the general problem of "seeing into the earth." A first generation radar coal thickness sensor, the RCTS-1, has been developed and field-tested in both underground and highwall mines. The noncontacting electromagnetic technique uses spatial modulation created by moving a simple sensor antenna in a direction along each axes to be measured while the complex reflection coefficient is measured at multiple frequencies over a two-to-one bandwidth. The antenna motion imparts spatial modulation to the data that enables signal processing to solve the problems of media, target and antenna dispersion. Knowledge of the dielectric constant of the media is not necessary because the electrical properties of the media are determined automatically along with the distance to the target and thickness of each layer of the target. The sensor was developed as a navigation guidance sensor to accurately detect the coal/noncoal interface required for the USBM computer-assisted mining machine program. Other mining applications include the location of rock fractures, water-filled voids, and abandoned gas wells. These hazards can be detected in advance of the mining operation. This initiating technology is being expanded into a full threedimensional (3-D) imaging system that will have applications in both the underground and surface environment.