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By A. Z. Dimitroff

An improvised rock- dust disseminator, consisting of a 10-gallon galvanized metal milk can that dispenses rock dust in return air currents by the injection of compressed air has reduced the float dust explosion hazards at the Koehler coal mine, Koehler, N. Mex.

Jan 1, 1965

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

CALCULATION OF MINE HEAD LOSSES FROM ALTIMETER SURVEY DATA USBM PENNSYLVANIA STATE UNIVERSITY - MINERAL ENGINEERING DEPARTMENT USBM USBM USBM THIS PROGRAM CALCULATES PRESSURE LOSSES USING THE USBM METHOD GIVEN USBM IN USBH IC 7809 BY MCELROY AND KINGERY.1957. THE MAJOR DIFFERENCE USBM BETWEEN THIS PROGRAM AND THE CITED REFERENCE IS THE TREATMENT OF AIR USBM

Jan 1, 1977

By R. R. Sayers

The terms "sanitation and }\Vgienen are often used interchangeably, but it is more "' usual to apply ttsani tat ion'' to th environment or surroundings, and nr.ygieneto the iiiividual, The subject,. h9wever, is so broad that only a few of the phases of sanitation will be di.acusae in ·this paper, vmile the various Fsea of hyg:tene will be deferred for later consideration. One of the bes.t .iaf ini tions of sanitation that I have hearci was given by ur. L. L • Lumsden, of the U, S. Public Heal th Service, who state.d that "'sanitation is t-he c.oir .. 'Don-sens$ application of the principles of cleanliness,

Aug 1, 1922

By Charles L. Parsons

During the past year, in producing 500,000,000 tons of coal we wasted or left underground, in such condition that it probably will not be recovered in the future, 250,000,000 tons of coal; we turned loose into the atmosphere a quantity of natural gas larger than the total output of artificial gas during the same period in all the towns and cities of the United States; we also wasted or lost in the mining, preparation, and treatment of other important metalliferous and non- metalliferous minerals from 10 to 50 per cent of the year's produc- tion of such minerals. These losses serve to indicate the importance of inquiries and investigations by the Federal Government for the purpose of lessening the waste of essential resources-investigations on the same general lines as those looking to a reduction in the loss of life in the mining operations of the country and the far more exten- sive investigations looking to the more efficient production and use of agricultural products, both of which are being conducted by the Federal Government. In a consideration of the possible activities of the individual, the State, and the Federal Government in behalf of a less wasteful use of our mineral resources certain facts and principles should be kept clearly in mind, namely: That the present generation has the power, and it will exercise the right, to use as much of the country's resources as it actually needs; there can and there will be no such thing as stinting the present gen- eration by bottling up resources for the use of the future. That the Nation's needs are not likely to be curtailed; these needs will increase with the extent and diversity of the Nation's industries, and they will increase more rapidly than population increases, for the reason that the per capita consumption of mineral products is rapidly increasing; and That the men of this generation will not mine, extract, or use these resources at continuous financial loss to themselves in order that some- thing may be left for the use of future generations; there can be no such thing as a mineral industry without profits.

Jan 1, 1912

By Henry Kreisinger, F. K. Ovrız

Some of the investigations conducted by the Bureau of Mines have for their object the collecting and disseminating of information regard- ing methods by which the fuels of the country may be most effi- ciently used. As the analysis of flue gases tends to develop better methods of firing, which in turn reduces waste of fuel, the Bureau of Mines in this bulletin presents for the benefit of those in charge of boiler plants and all other persons interested detailed information on methods of sampling and analyzing flue gases, and on the utilization of the analyses in promoting boiler-room economy. This bulletin is intended to be a companion to Technical Paper 80," and is written in plain and nontechnical language, as far as pos- sible, so that it may be readily understood by persons who have not had the advantage of a technical education. Whenever possible, illustrations of apparatus and methods of handling have been used rather than elaborate descriptions. The material presented in this report is arranged in two parts. The first part contains the description of the apparatus and the methods used in sampling and analyzing flue gases. The second part gives experimental results obtained with the different methods of sampling and collecting flue gas that are recommended in the first part of the report. Only simple apparatus and methods are considered, as they are accurate enough to show the large heat losses due to the use of too much air, and are also accurate enough to indicate any incomplete combustion losses of economic importance. Without doubt the loss due to large excess of air is the greatest one in the boiler room, and can usually be greatly reduced by making proper use of gas analysis. Before engineers in the isolated industrial plants can be induced to analyze for small traces of combustible gases, they must be first taught how to analyze for carbon dioxide (CO), and they must learn to appre- ciate the great possibilities of reducing loss from large excess of air. Furthermore, in the face of the great difficulty of obtaining a fair

Jan 1, 1915

By A. Z. Dimitroff

An improvised rock-dust disseminator, consisting of a 10-gallon galvanized metal milk can that dispenses rock dust in return air currents by the injection of compressed air has reduced the float dust explosion hazards at the Koehler coal mine, Koehler, N. Mex.

Jan 1, 1965

By M. B. Cooke

In the course of investigation now in progress by the Bureau of Mines into the nature of " gum forming" constituents of gasoline , several gasolines and other petroleum products were heated in a small bomb , and pressures of considerable magnitude were developed . As the Bureau has received many inquiries for data showing the pressure that may be developed in a still when gasoline or other oil is subjected to elevated temperatures , it was thought advisable to record the pressures observed at various temperatures in the course of this work . data were merely a by- product of the main investigation . These Gasoline and similar products are very complex mixtures , and it is difficult to determine accurately the true vapor pressures , hence the vapor pressures of the oils used in these tests have not been studied in detail , but the data obtained may be taken as representative of the pressure- temperature relations of the various oils in commercial work.

Jun 1, 1922

By James A. West

THE South Asian countries of India, Ceylon, Pakistan, Afghanistan, Nepal, Bhutan, and Sikkim have a large variety of mineral resources; however, in spite of mineral industry growth during 1964, development of resources remained far short of possible development, and, in terms of value of trade in minerals, the area remained a sizeable net importer. India's mineral industry is by far the most significant; its minerals production in 1964 accounted for more than 90 per cent of the total value of all minerals produced in the area. The total value of all minerals produced in South Asia in 1964 was only about 1 percent of the area's estimated gross national product of $55,125 million. Despite the rather small current contribution of minerals to the economy, development of mineral resources figures prominently in plans for the industrial development of the nations of this area.

Jan 1, 1966

By Richard E. Dawes

Physical variables, a principal factor in the economies of mineral production, affect both capital and direct operating costs. By using a revenue-cost system for the framework, the analyses of revenue and cost categories demonstrate the relative importance of groups of physical variables, whether explicitly defined or not, to a lead-zinc mining operation. Physical variables affecting the producer represent about 60 percent of the total system influence as expressed by cost ranking. Other physical variables affect the remaining costs as controlled by the smelter, the transporter, and the landowner. Such resource conservation aspects as mineral losses due to mining method and mineral processing constitute a portion of the total revenue effects of physical variables. The physical variable revenue-cost system presented in this report offers a framework for cost-benefit analysis of mineral related research.

Jan 1, 1969

By George S. Koch

The distribution of gold in part of the Getchell mine, Humboldt County, Nev., is presented through the statistical analysis of 956 assays of rock cuttings from wagon-drill holes. Two methods to predict grade in undeveloped parts of the ore body are evaluated, and the possibility of sampling bias is tested. The distribution of gold is compared with that in three other Nevada gold deposits of the same type characterized by gold particles mostly of submicron size associated with carbonaceous rocks, and also with that in deposits with coarse-grained gold. Usually, fewer samples of a given type are required to make a satisfactory grade estimate for submicron deposits than for coarse-grained deposits. The economic consequence is that submicron gold deposits are likely to be less expensive to sample and evaluate than coarse-grained deposits.

Jan 1, 1970

By W. Blake, J. K. Whyatt, T. J. Williams

Researchers at the U.S. Bureau of Mines collected and analyzed over core measurements and other indicators of in situ stress characteristics at the Lucky Friday Mine, Mullan, ID. An analysis of these data revealed that significant local variations in in situ stress are present in this mine and that these variations existed prior to mining. High stresses were found to be associated with the most competent strata and a locked section of a fault. An estimate of the predominant stress field was developed for mine-wide modeling. The estimate shows that the greatest principal stress was oriented north of northwest. This information should provide a basis for mine-wide structural modeling of the Lucky Friday Mine and should generate important insights into localized stress conditions, which may significantly affect both local and mine-to-mine variations in seismicity induced by excavation.

Jan 1, 1995

By J. Litsenberger, T. E. Marshall, P. R. Coyle, L. J. Prosser, A. T. Iannacchione

For the first time in an underground stone mine, the relationship between roof movement and microseismic emissions was examined in conjunction with two distinct roof fall areas. As roof monitoring increases in acceptance and monitoring technology advances, the goal of providing reliable roof fall detection systems to enhance the safety of underground mine workers moves closer to reality. Instrumental to reaching that goal is the ability to interpret accurately and completely roof movement and microseismic emissions, which can serve as precursors to roof falls. This paper examines the capabilities of convergence and microseismic monitoring systems to better understand roof rock failure mechanics and to anticipate roof falls. An understanding of how these techniques are used and how they interact with each other is critical in developing the most effective ground control strategy for our nation’s mines.

By Lucia Kuizon

The Morongo Wilderness Study Area (WSA) is in south central San Bernardino County, California. U.S. Bureau of Mines examined the area during the fall of 1983. No mines, prospects, leases, or mining claims were found in the WSA. There are no known mineral deposits within the study area boundaries. Sand and gravel in the area is suitable for many types of construction uses, but similar and larger deposits outside the WSA are closer to markets. No energy resources have been identified in the WSA.

Jan 1, 1984

By Lloyd A. Morley, Robert Stefanko

Table

Jan 1, 1974

By Martyn F. Roetter

The work of the operational communication systems' group dealt with a range of communication needs and functions within mines, primarily along haulageways, to and within sections up to the working face itself, and in mine shafts. A mixture of communication techniques and hardware is needed to satisfy this variety of communication needs within the differing environments encountered in U.S. mines. Substantial progress, both experimental and theoretical, has been made in recent years towards developing alternative communication systems suitable for use in mines which are based on "guided" waves, including wire-less (waveguide-like propagation in mine tunnels) and wire-based systems (leaky coaxial cables or wires) . Major priorities identified for further work needed to confirm (or deny) the applicability, and refine the operational specifications of promising communication systems for mine use include: Short-Term Projects o Cost/performance analyses of promising leaky coaxial cable and UHF radio communication systems which require further data from: - Experimental investigation under U.S. mine conditions of the performance of potentially applicable leaky coaxial cable communication systems developed in Europe (France, Belgium, and the U.K). - Cost estimates on these coaxial cable communication systems. - Measurements of UHF radio propagation in low-coal mines. - Investigation of the influence of obstacles (e.g. shuttle cars and section machinery) in the entries on UHF radio propagation in mines. o Investigation of the problems of transmitter and receiver coupling and termination matching associated with the two-way propagation of low frequency radio waves in hoist shafts.

Jan 1, 1973

By Thomas M. Barczak

Longwall operators are again pushing the envelope in terms of life expectancy for longwall shields. State-of-the-art shields are now expected to last more than 60,000 loading cycles, twice the life expectancy compared with those of a decade ago. A review of trends in shield design shows that shields continue to increase in both size and capacity. Some state-of-the-art shields now weigh over 30 tons and provide up to 1,200 tons of support capacity. Although life expectancy has increased and modern shields are structurally more reliable, premature failures do still occur. This paper provides an engineering and operational assessment of shield design and provides key points to observe in what causes premature shield failures. Design practices to improve structural margins of safety that will prevent premature failures from occurring are also examined. A survey of recent shield failures is provided, as well as trends in shield design and how they might impact the performance and longevity of a shield. Hydraulic failures are more common than structural failures. Although hydraulic failures occur on all aging longwall shields, they often go undetected for long periods, resulting in degraded support capacity that can lead to serious ground control problems. The fundamentals of shield hydraulics are described in order to evaluate hydraulic failures that plague all shields at some point in their service life, and practical methods to detect hydraulic failures are examined. The paper concludes with recommendations for inspecting damaged shields and safety precautions regarding their continued use.

Jan 10, 2000

By R. Karl Zipf

Use of Salamon's stability criterion in underground mine design can prevent the occurrence of catastrophic domino-type pillar failure. Evaluating the criterion requires computation of the local mine stiffness and knowledge of the post failure behavior of pillars. This paper summarizes the status of the practical use of this important criterion and suggests important research to improve our capabilities. Analytical and numerical methods are used to compute the local mine stiffness. Work to date in computing local mine stiffness relies mainly on elastic continuum models. Further work might investigate local mine stiffness in a discontinuous rock mass using alternative numerical methods. Existing post failure data for coal pillars are summarized, and a simple relationship for determining the postfailure modulus and stiffness of coal pillars is proposed. Little actual postfailure data for noncoal pillars are available; however, numerical models can provide an estimate of post failure stiffness. Important factors controlling postfailure stiffness of rock pillars include the postfailure modulus of the material, end conditions, and width-to-height ratio. Studies show that the nature of the failure process after strength is exceeded can be predicted with numerical models using Salamon's stability criterion; therefore, a method exists to decrease the risk of this type of catastrophic failure. However, the general lack of good data on the postfailure behavior of actual mine pillars is a major obstacle. Additional back-analyses of failed and stable case histories in conjunction with laboratory testing and numerical modeling are essential to improve our ability to apply the stability criterion.

Jan 5, 1999

By D. B. Dow

The transportation of any commodity which is actually or potentially a source of fire or explosion, has been made safe, insofar as humanly possible, by rigid requirements as to inspection mechanical safety devices, and by printed labels. For the most part these precautions have been sufficient. This is evident when it is considered that in the thousands of instances in which commodities with a great fire risk have been transported, few disasters have occurred. This paper deals with the recent gasoline explosion which occurred at Memphis, Tennessee. At 7:50 a.m. January 24, 1921, vapors from a tan: car of gasoline became ignited and resulted in a blast that killed eleven people and badly injured nineteen others. Probably forty or fifty men, women, and children received slight injuries from falling debris or from burns. The explosion wrecked an oil plant, leveled a block of frame buildings, and broke window panes within a radius of five blocks.

Feb 1, 1921

By G. S. McCaa

Rock-dusting is an. effective means of preventing coal-dust from propagating an explosion in a coal mine, but it will not prevent gas from igniting-explosively and with much attendant damage locally. Ventilation must therefore be effective at all times, regardless of the employment of other explosion-prevention methods, if gas explosions are to be avoided. This paper describes a gas explosion which occurred in as bituminous mine that was well rock-dusted at the point of ignition and which exemplifies the value of rock-dusting, the necessity of maintaining effective ventilation, and the need of permissible rock-dusting machines receiving power from a permissible locomotive. Description of Explosion The mine in which this explosion occurred is developed on a panel system in a practically level seam; the panel entries are driven in pairs, and the air current intakes on the right entry and returns on the left entry. Near the mouth of the intake a door is placed to control the ventilation; board stoppings are placed in crosscuts, except the second from the face, in which a brattice cloth curtain is hung, the last crosscut is left open and line brattices conduct the air current from the last crosscut to the faces. In No. 7 entry the last cross-cut was 152 feet from the face, the line brattice being within 38 feet of this face, and the second crosscut was 250 feet outby the face of the back entry or return. Seven days prior to the explosion the intake and return entries were rock-dusted to within 38 feet of the face, and as the entry had advanced during the week, the rock-dusting was to be extended.

Jan 1, 1929

By K. L. Cashdollar

A project to evaluate the South African bagged stone dust explosion barrier was successfully completed at the National Institute for Occupational Safety and Health (MOSH), Pittsburgh Research Laboratory's (PRL), Lake Lynn Experimental Mine (LLEM) during the period November 1999 through May 2000. The tests were conducted in a three- entry section of the LLEM. Two types of explosions were used to evaluate the distributed and concentrated bagged barrier performance in a multi-entry mine section. The fuel zone of the first explosion type was only in the center B-drift. In the second explosion type, coal and stone dust mixtures were place in all three drifts. A total of six explosions, including two baseline and four barrier evaluation explosions, were conducted. Of the four barrier explosions, the distributed and concentrated barriers were each evaluated against the two explosion types. For these explosion tests, the distributed barrier extended from about 74 to 170 m and the concentrated barrier from about 74 to 104 m in B-drift. The distributed barrier successfully stopped flame propagation in both types of explosion tests. The flame extended further for the explosion tests where the dust was loaded in all three entries compared with dust loaded only in the center entry% but in both cases the flame was stopped within the barrier zone. The concentrated barrier was also successful in stopping flame propagation m both explosion tests. From the full-scale experimental mine test results, it can be concluded that both bagged barrier designs were effective in stopping coal dust explosions in the multiple entries of the LLEM.