Search Documents

By John Owens, Marc Endicott, Hamid Maleki

This study presents a historic overview of the role of mobile roof support (MRS) technologies in improving stability and worker safety and presents the results of recent field evaluations of the MRS load rate monitoring device and other remote deformation-monitoring techniques. Field studies were implemented at two sites in cooperation among researchers from the National Institute for Occupational Safety and Health (NIOSH), Maleki Technologies, Inc., and J. H. Fletcher & Co. The objective of the field programs were to (1) study the interaction between MRS’s and coal mine strata and (2) develop and test suitable monitoring systems for assessing roof and pillar stability. An MRS consists of a roof canopy, four hydraulic cylinders, a caving shield canopy, and associated electromechanical systems mounted on crawler tracks. The machines are controlled by radio from a remote location and operate on self-contained power units. Typically, MRS’s have capacities of 5,340 and 7,120 kN (600 and800 tons). In comparison to posts, an MRS is capable of maintaining the yield load after significant amounts of roof-floor deformation. Because the mining cycle is accelerated, MRS’s help reduce the potential for time-dependent roof falls. MRS performance has been monitored in the laboratory under controlled static loading conditions and in the field under deep, two-seam mining conditions. Laboratory studies have quantified support capacity and system stiffness as a function of machine height. Field investigations have focused on determination of optimum operating conditions and development of warning systems that indicate excessive load on the machine and/or impending roof-pillar stability problems. Analyses of field data show that roof instabilities are influenced by (1) pillar failure, (2) pillar yielding, (3) mine seismicity, (4)geologic structures, and (5) panel layout designs and mining practice.Pillar yielding and failure (unloading) and seismicity can be conveniently monitored by the load rate monitoring device, but for consistent detection of roof falls, additional deformation measurements directly within the cuts are needed.

By David Burgess

Natural gas is a general term applied to the gas obtained from oil or gas wells. It is the most widely used of all gaseous fuels. The principal disadvantage in the use of this and other gaseous fuels is the difficulty encountered in the storage and transportation of large quantities in the gas state. Handling in the liquid state is possible, but reduced temperatures are required since methane (table 1) is the principal component of most natural gases that are used as fuels. Actually, liquid storage has been utilized both here and abroad;3 however, the Cleveland disaster4 has pointed out the need for a critical evaluation of the hazards involved in the storage of this cryogenic fuel. Accordingly, a program was undertaken to obtain basic data that could be used to assess these hazards. In this report, the factors to be considered in an evaluation of the fire and explosion hazards associated with any fuel are each discussed briefly. These factors are then used to assist in the design of experiments for the evaluation of the hazards associated with liquefied natural gas (LNG) relative to those associated with other common fuels. Experiments have been conducted on the vaporization of LNG, the mixing of LNG vapors with air, the effect of temperature and nitrogen dilution on the limits of flammability of methane in air, the burning rates of LNG and other fuels, flame radiation, and extinguishment of fires above liquid pools. Based on the results of these experiments, LNG can be stored safely in suitably designed above-ground tanks surrounded by earthen dikes in much the same manner as gasoline.

Jan 1, 1962

The Technology Transfer Seminar on Mine Communications held on March 21-77, 1973, at the Pittsburgh Mining and Safety Research Center, Bruceton, Pa., presented information about recently developed equipment, instruments, and techniques for use in mine communications systems. All of the basic ideas presented in the fine seminar are operational in the Bureau of Mines Safety Research Mine in Bruceton.

Jan 1, 1974

By Francis X. Cannaday

The purpose of this investigation was to find whether the moduli of elasticity obtained were the same for the following methods : ( 1 ) Deformation of a borehole in a prism subjected to uniaxial stress ; ( 2 ) deflection of a thin beam of uniform cross section uniformly loaded ; ( 3 ) sonic - pulse velocity measurements , and ( 4 ) strain measurements on a prism under uniaxial stress . The rock tested was chosen for its good elastic behavior and relatively good homogeneity and elastic isotropism . The same rock was used for all methods . Results indicate that for given environmental and stress conditions the moduli obtained by each of the four methods check one another within the limits of experimental error and that the differences introduced which are characteristic for each method are smaller than physical variations within the rock tested .

Jan 1, 1964

By V. H. Gottschalk

Among the procedures developed by the Germans for providing the tonnage of iron powder needed to make rotating bands for artillery shells is the use of a ceramic tunnel kiln, not only for finishing the reduction of centrifugal powders but also for making so-called "brickyard sponge iron," which, after crushing and grinding, seems to yield a product suitable for powder-metallur- gical purposes. The final report issued jointly by the German Powder-Metallurgical Society (DPG) and the Chemical-Metallurgical Branch of the Research Depart- ment of the Metallgesellschaft, Inc. (ZFC of MG) gives the available details of this procedure, which may be regarded as a further development of the process in commercial use since 1911 at a ceramic plant in Hoeganaes, Sweden. The Bureau of Mines' wartime development of the Hoeganaes process also cul- minated in the adaptation of ceramic tunnel kilns for carrying out the solid- carbon reduction of iron ores, and comparison with the German technique should further advance the art. This information circular is issued as a supplement to Bureau of Mines reports of investigations Nos. 3819,2 3822, 3841,2 and 4271, on brick- yard sponge iron and is based on four German reports entitled "Making Iron. Powder in the Tunnel Kiln," translated from FIAT microfilm reel H-46, frames 9190-9209, 9280-9299, 9339-9357, and 9377-9384 (PB L 70042), which represent the four original research reports, Nos. 2005, 2008, 2010, and 2012, respec- tively, of the Metallgesellschaft, Inc.

Aug 1, 1948

By Clinton C. Knox

Attention of mine operators and engineers in the Picher zinc-lead field has been drawn increasingly in recent years to marginal ore deposits lying at greater than normal depth below surface in the marked structural depressions known as the Miami and Bendelari troughs. Not only mining but prospect and development drilling is relatively costly in the bottoms of the structural depressions known as the. Miami and Bendelari troughs which cross the center of the Picher field. Nevertheless, operations by various mining companies in recent years have shown that no insuperable problems exist, and with the gradual lowering of grade cut-offs throughout the field, certain potential deep-ore areas, previously only partly explored seemed worthy of further investigation. Some such areas were called to the attention of Bureau of Mines engineers by lease holders and operators, while others were noted in the course of Bureau's systematic investigation of Tri-State ore reserves. The writer was assigned to make a study of. those possible "trough extensions," in the course of which all available nine maps, drill logs, and prior reports were assembled. Subsequently 41 churn drill holes were bored by the Bureau in the periods October 1944 to May 1945 and October 1946 to April 1947. The general area under investigation this project is indicated on figure 1, which likewise shows its relation to nearby towns, roads, and railroads. The location of individual deposits included in the report is indicated more clearly on figure 3. Minable ore was found in only two holes, and the structural information procured by drilling was less encouraging than anticipated. This report, however, presents all factual data obtained, in the belief that they may be useful in subsequent prospecting and development projects in the areas investigated. There are also set forth some of the stratigraphic data relative to the Picher field ns a whole and the Miami and Bendelari troughs which were assembled in the preliminary investigation of this project.

Jan 1, 1949

By M. R. Geer

The Bureau of Mines examined the washability data for 25 Appalachian coals requiring low-density washing to reduce sulfur content to 1 percent, using the distribution-curve method. The purpose was to estimate how closely theoretical sulfur values could be approached, what yields of washed coal could be expected, and the recovery efficiencies that might be achieved. Assuming that the run-of-mine coal would be crushed to 3/8 inch and cleaned in dense-medium cyclones, the calculations indicate that theoretical sulfur contents could be approached closely when cleaning at a specific gravity of separation as low as 1.30. With coals that have favorable specific gravity compositions the recovery efficiency anticipated for cleaning at 1.30 specific gravity is surprisingly high. Similar calculations for cleaning with concentrating tables at intermediate specific gravities indicated that theoretical sulfur contents at 1.50 specific gravity could be approached closely with some coals but not with others. The calculations suggest that operating a table at a specific gravity of separation much lower than about 1.50 probably would be unsatisfactory with most coals.

Jan 1, 1968

By Paul T. Allsman, William H. King

This paper describes the mineral deposits and discusses mining and milling methods and related operating conditions in an important gold , silver , lead , and zinc producing area in Ouray , San Juan , and San Miguel Counties , Colo . , embracing 250 square miles . The area is extremely rigged , ranging in altitude from 8,000 to 14,000 feet . White men first penetrated the area in 1860 , when a group known as "Baker's party " reached the Animas River at the present site of Silverton . Difficulty with the Ute Indians and severe winter conditions forced the group to leave and discouraged prospecting until 1870 when a second party reached the area and succeeded in producing 27 tons of ore yielding $ 150 a ton in gold . In 1874 , a treaty with the Indians opened the way for settlement , and mining was established . The total production of recovered gold , silver , copper , lead , and zinc from 1873 to 1947 in the three counties is valued at $347,057,047 . The greatest amount of the total production of metals has come from quartz veins in a series of volcanic flows and tuffs covering the area and comprising a blanket 4,000 to 6,000 feet thick . The igneous rocks were laid down upon an old , erosion surface and are underlain by Paleozoic and Mesozoic sedimentary rocks and pre - Cambrian metamorphic rocks . The entire series has been intruded in late Tertiary time by volcanic dikes and larger intrusive masses . Because of the great differences in relief generally , mining is con-" ducted through long adits to a depth of nearly 3,000 feet below surface in places . Walls of the veins generally stand well , and shrinkage stoping is the most common method of mining . As virtually all of the ore is sulfide below the zone of oxidation , flotation is the common method of milling . Generally , where gold is important , provision is made for its removal by jigs . Bulk concentration of the sulfides is practiced at smaller mills , but the larger operations make a selective lead and zinc concentrate or a lead , zinc , and copper . concentrate . ·

Mar 1, 1950

By P. H. Francis

In This report, factors which currently enter into the design, manufacture, and quality assurance of explosion-proof enclosures are reviewed, with special emphasis given to the sealing concepts and sealants/cements, per se, for lenses. The physical and mechanical properties of a number of representative sealants and adhesives are measured, and found to exhibit great variance, with few discernible trends which might afford a firm base on which to establish minimum property standards. Accordingly, acceptance criteria for adhesives and sealants are suggested based on the survivability of an explosion-proof enclosure as a structure rather than upon the minimum mat real properties of its constituents. Procedures or surface preparation of adherends, and for quality assurance, also are proposed.

Jan 1, 1980

By J. J. Forbes

First - aid training is an essential part of safety programs in the mining industry , but it is only a means to an end ; first -aid training will not eliminate accidents , but unquestionably it is of considerable value in any accident prevention program . Numerous features should be incorporated in any efficient , well - developed safety plan ; in addition to first -aid training safety work , to be reasonably effective , should include the establishment and maintenance of a safety organization , safety competitions between mines or sections of mines , safety- inspection committees , accident - investigation committees , safety meetings of mine officials , safety bulletins and posters , employees ' safety publications , Holmes Safety Chapters (which provide for monthly safety meetings of all employees ) , and numerous other activities looking to safe operation of mine or plant . These features are supplementary to the fundamentals of safety-- adequate and effective supervision and discipline . Years of experience , however , have demonstrated that first - aid training is a good accident -prevention auxiliary and should be made an integral part of every company's safety program . Many safety-organization plans have failed because they have been based upon the assumption that the supervisory force should be given full authority and responsibility for achieving safety and eliminating accidents and that the workers , who are most vitally concerned , are nonessential . First -aid training causes the employees to feel that they have a personal and full participation in the safety program and is now available so readily that no individual or organization has any valid excuse for not having it . Early investigations made with a view to bettering health and safety conditions among the employees in the mineral industries demonstrated the need of prompt care of injured employees because , under the difficulties inherent in the occupation , seemingly unimportant wounds , when not treated promptly, became infected and caused permanent disability and even death . Many seriously injured persons , brought out of mines and plants by fellow workers who were ignorant of the approved methods of giving first aid or of safe means of transportation

Aug 1, 1934

By H. H. Schrenk

Much has been written and said concerning tables of permissible or maximum allowable concentrations of various toxic substances in air, but not enough attention has been given to their limitations and how to use them intelligently . There is a tendency to place too much reliance on figures , with little or no consideration of their real meaning . The repeated publication of a figure often adds significance to it far beyond that intended by the original author or publisher . How are these figures referred to as "maximum allowable concentrations " established? What is their real meaning? To answer these questions it is necessary first to define maximum allowable concentration . The usual definition is somewhat as follows : "The average concentration to which an industrial worker can be exposed for 8- hours daily for an indefinite period without injury or occupational disease . This definition is made up of the following items : ( 1 ) Average concentration, ( 2 ) 8 - hour day , ( 3 ) indefinite exposure period , and ( 4 ) lack of injury or occupational disease . There is some controversy regarding item ( 1 ) , items ( 2 ) and ( 3 ) are usually though not invariably accepted , and there is definite disagreement regarding the interpretation of item ( 4 ) . . To reach a more satisfactory interpretation of maximum allowable concentration , attention is directed to ( 1 ) the development of tables of maximum allowable concentrations , ( 2 ) criteria on which limits are based , and (3 ) methods used to obtain data on which limits are based .

May 1, 1948

This status report contains 39 individual reports on health and safety research projects now being conducted or recently completed by the Bureau of Mines. The Reports on health research cover industrial hygiene, respirable dust, ventilation, noise control, and radiation hazards. The safety research reports cover industrial hazards, ground control, fire and explosion prevention, and methane control. Each report includes background information, a discussion of research progress, and an assessment of each project's current status.

Jan 1, 1979

By C. Q. Cupps, R. F. Zaffarano, J. Fry

Reservoir oil analyses from seven wells in the Greater Clareton area have been included in a study of the original characteristics of oil in the Newcastle sandstone reservoir . These data correlated with areal location of the wells show an increase of saturation pressure in a general north - south or downdip direction . The increase amounts to about 500 psi in more than 17 miles , which corresponds to a depth increase of about 1,600 feet . To facilitate application of the data to engineering analyses , average characteristics are given for arbitrary north and south divisions of the 22 - mile - long producing area . The downdip increase of saturation pressure is taken as evidence of updip diffusion of solution gas from a somewhat higher concentration at the bottom of the reservoir . This effect is opposite to that previously observed in two prominent high- relief reservoirs in the Rocky Mountain area . The increasingly greater saturation pressures southward or downdip in the Greater Clareton area suggest a continuing migration of fluids into the structure .

Jan 1, 1964

By Robert J. Tuchman

This report presents the origins of the Bureau of Mines and the evolution of the Pittsburgh Research Center from its inception to its present form. Areas of major research emphasis over the years, as well as administrative reorganizations, are discussed.

Jan 1, 1998

By W. J. Wenger

Colorado has been producing petroleum since 1863 but only recently has become a major oil State. The first well was drilled on Oil Creek near Florence, but out-put was relatively small until discovery and development of the Weber sandstone reservoir at Rangely. Oil was discovered in the Weber sandstone in 1933, and the reservoir was developed after 1940, bringing Colorado, in 1949, to 11th place among the 48 States as an oil producer. Colorado's output increased further because of the discovery and development of many fields in the Julesburg Basin since 1949 By 1954 Colorado was in ninth place and maintained that position through 1955.4/ Between 1946 and 1951, Colorado's oil production more than doubled, while the total United States production increased only 25 percent. It seems probable that production will continue to expand in Colorado for many years. This report presents analyses of 92 crude oils from 73 fields representing 90 percent of the production in 1955. Abridged analyses are listed for easy comparision, and complete analyses arc given in the appendix. Oil samples were collected for study from many different sources. Although many of the newer fields were not sampled, their oils probably are very similar to those from corresponding formations that were studied and tabulated.

Jan 1, 1957

By E. G. Davis, H. P. LeVan, L. S. Smith

Leaching of a Georgia umber ore when using both ferrous sulfate and pickle liquor was studied in the laboratory . The ferrous sulfate content of the leach solution was the major factor affecting the extraction of manganese from the ore . Time , temperature , and the sulfuric acid content of the leach solutions had relatively little effect on leaching of manganese from the ore ; however , these factors did affect the amount of iron extracted from the umber and/or precipitated from solution . Simulated countercurrent leaching of the ore with pickle liquor containing 130 gpl (grams per liter ) ferrous sulfate ( 48 gpl ferrous iron ) produced a pregnant solution having 16 gpl manganese and 41 gpl iron . Filtration tests of the leach slurries indicated that separating the leach solution and solids by vacuum filtration was impractical , whereas pressure filtration was feasible when the cake thickness was limited to about three- fourths of an inch . Fired pellets of the filter cake yielded a firm , hard product analyzing 56 percent iron and less than 0.1 percent sulfur .

Jan 1, 1964

By Joseph L. Jordan

Coal is essential to America?s future energy needs. To meet these needs mining methods must be safe, economical, and environmentally acceptable. Belt conveyor systems for coal haulage from surface mines offer great potential in this situation. The advantages over conventional truck haulage are particularly promising for area strip mines in western coal fields such as the Powder River Basin where relatively thick, flat-lying coal seams occur. The current demand for low-sulfur coal specifically emphasizes the need for better mining methods in these areas. Underspoil haulage is the term applied to transportation of coal from the pit to the surfate in area strip coal mines by belt conveyors in tunnels under the spoil. The advantages over trucks include lower manpower requirements, greater pit safety and efficiency, and improved reclamation procedure. This evaluation includes a comparison of total mining costs for truck haulage versus six variations of the underspoil haulage concept. The more efficient of these underspoil haulage systems have economic advantages over truck haulage which become more pronounced with deeper overburden, thicker coal, and higher annual production.

Jan 1, 1977

By Hugo E. Camargo

Noise Induced Hearing Loss (NIHL) is the most common occupational disease in the U.S. with devastating consequences particularly in the mining industry. A study conducted by the National Institute for Occupational Safety and Health (NIOSH) revealed that 90% of coal miners have hearing impairment by age 50, compared to only 10% of those not exposed to occupational noise. According to the Mine Safety and Health Administration (MSHA), Continuous Mining Machine (CM) operators account for 30% of workers exposed to noise doses exceeding the Permissible Exposure Level (PEL). This number becomes more dramatic considering that 49% of the total national underground coal production is extracted using these machines. In this context, NIOSH is conducting research to identify and control dominant noise sources in CMs. Previous noise source identification was performed using a Brüel &Kjær (B&K) 1.92-m diameter, 42-microphone phased array. These measurements revealed that the impacts from the conveyor chain onto the tail roller, and the impacts from the conveyor chain onto the upper deck are the dominant noise sources at the tail-section of the CM. The objectives of the work presented in this paper were: 1) To rank the noise radiated by the different sections of the conveyor, and 2) to determine the effect of a urethane-coated tail roller on the noise radiated by the tail-section. This test was conducted using an Acoustical and Vibrations Engineering Consultants (AVEC) 3.5-m diameter, 121-microphone phased array. The results from this new test show that a urethane-coated tail roller yields reductions in the tail-section of 2 to 8 dB in Sound Pressure Level in the frequency range of 1 kHz to 5 kHz. However, integration of the acoustic maps shows that the front-section and mid-section of the conveyor also contain dominant noise sources. Therefore, a urethane-coated tail roller in combination with a chain with urethane-coated flights that reduces the noise sources in the front and mid sections of the conveyor is required toyield a significant noise reduction on the CM operator?s overall exposure. These results show the applicability of phased array technology for low frequency noise source identification.

Jan 1, 2008

By Terry Muldoon

In conventional noncoal, room-and-pillar mining, the cutting machine is frequently a major source of airborne dust. Water is often used for dust control. An evaluation of typically used water systems during this program showed that they reduced dust levels by 60 to 70 percent over dry cutting when at least 0.5 gpm of water was applied. These systems, however, are only marginally effective in maintaining compliance levels and the added moisture causes operational problems. During the program, three additional dust control systems were designed, fabricated, and evaluated. The first, a hollow cutter bar, was designed to capture dust in the kerf at the cutting zone. The system was only marginally effective in reducing dust levels due to its lack of control of other sources. Large quantities of material captured by the system made it operationally questionable. The second, a machine mounted exhaust system, was extremely effective in capturing virtually all the dust generated in the heading. The captured dust was ducted out of the heading and exhausted downstream in the crosscut. Exhausting the dust without scrubbing, however, creates problems for personnel working downstream of the cutting machine. Successful application would require changes to the mine ventilation system and mining sequence. The third, foam, injected foam from an onboard generator through a channel to the cutting zone at the tip of the bar. Test results showed that foam, using 1/3 to 1/2 the total fluid quantity, was equally effective when compared to the mine's current water system.

Jan 1, 1983

By F. B. Tough

"INTRODUCTION Organizations formed for the purpose of conducting conservation work in oil fields, in order to conserve and prolong the supply of crude petroleum are rare and novel. Such an organization is the Rocky Mountain Petroleum Association, Denver, Colo, As our production of petroleum can no longer keep with the consumption, the plan of organization, character of work, and results obtained by this association are well worth considering. It is hoped that the results achieved in the Wyoming fields will serve to stimulate similar organizations among operators in the state or other oil fields of the United States, The Rocky Mountain Petroleum Association, Danvers Colo., was formed in May, 1919. It comprises the Midwest Refining Co,. The Ohio Oil Co., and the Continental Oil Co. These three companies entered into a cooperative agree¬ment with the Federal Bureau of Mines whereby $30,000 would be spent under the direction of the bureau, which agreed to furnish competent men, and to furnish the work and expenditure of funds. Although the financial burden for the first year's work, now drawing o a close, was carried by only three companies, they stipulated their desire that the benefit of the work should accrue to the industry, and that the personnel employed should be as zealous to assist one operator as another, without regard to whether ha was contributing to the support of the work or not."

Apr 1, 1920