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By M. A. Mahtab

This report describes the procedures used by the Bureau of Mines for obtaining attitudes of joints surveyed with a borescope in inclined boreholes. An algorithm for computing the dips and azimuths of the observed joints is presented. The algorithm is used to solve an example problem. A computer program based on the algorithm is listed. It is hoped that the procedures described here will be useful in treating large quantities of data obtained from comprehensive borehole surveys.

Jan 1, 1973

By R. V. Rahfuse

Noncaking 0- by 2 -inch subbituminous coal from New Mexico was gasified with air and steam at 205 prig using a stirred-bed producer to determine coal losses by entrainment in the gas for this low-sulfur, high-ash coal which contained 20 percent particles smaller than 1/16-inch sieve size. The use of fine-sized coal has particular importance because most production from mechanized mines is smaller than 2-inch size. This initial attempt showed technical feasibility for gasifying New Mexico subbituminous coal containing small-sized particles in fixed-bed producers without excessive coal loss by entrainment. Dust loss averaged about 2 percent of moisture-free coal, most of which was recovered from the gas. Ash clinkering was controlled by adding 1,010 lb/hr steam to reduce tempera¬tures in the combustion zone. Yield of low-Btu fuel gas, 150 Btu per scf, dry, amounted to 69,800 scfh from 1,490 lb/hr coal (as received) and 3,450 lb/hr air (dry).

Jan 1, 1974

By Robert L. Grayson, Syd S. Peng

"An airborne dust study was undertaken at a Southwestern Pennsylvania underground bituminous coal mine by the Pennsylvania Department of Mines and Mineral Industries in 1964 for the purpose of making recommendations and requirements regarding compliance with health and safety aspects of The Bituminous Coal Mining Laws of Pennsylvania, approved by the legislature on July 17, 1961. The study was designed to accurately represent the airborne dust conditions of the subject mine. Sampling by midget impinger of specific worker locations throughout the mine was accomplished. Sample analyses yielded dust concentrations to mppcf, particle size determinations in cumulative per cent less than specified cut-off diameters, and determinations of free silica percentages in total dust samples. The data from this study is further analyzed, and the results are presented.INTRODUCTIONThe Bituminous Coal Mining Laws of Pennsylvania, enacted in 1961, prompted a study of respirable coal mine dust by the Department of Mines and Minerals Industry in 1964. In recognition of their obligation for ensuring the health and safety of bituminous coal miners, the department set out to characterize the airborne dust of mines throughout the commonwealth. The purpose of the studies was to make recommendations and requirements for compliance with the law and for control of airborne coal mine dust in Pennsylvania mines.One such study was undertaken at an underground bituminous coal mine operating in the Pittsburgh Seam in Southwestern Pennsylvania. The study was desig11ed to sample specific worker locations throughout the mine site and characterize the respirable dust relative to each of them. A midget impinger was used to gather respirable range dust samples during an 8-hour shift. Continuous miner operator, roof bolter, stoper bolter, loading machine operator, shuttle car operator, gathering motorman, mainline motorman, and rotary dumper jobs were sampled underground. In addition, barge mover, coal sampler, fine coal operator, heavy media operator, and boiler room attendant occupations were sampled on the surface. The surface sampling was over a 71-hour shift because of UMWA contract provisions."

Jan 1, 1988

By L. D. Tracy

For many yeirs natural gas has been the principal fuel used in the he·1 ting furnaces in those mills located in the. Pi t-c;s. b.urgh district· \7hich manufacture bolts ., nuts, rivets, pick$, mattocks and srr.&11 for6ine;s. For a nUI.1"'.::>er of years the steady supply of this fuel has been more or less interrupted owing to the increased4and f·or d9mes tic use and to the increasing difficulty in securing an ad.eq_ua te c.1mount of natural gas. This condition has led a number of the steel compa.nies to substitute -oulvsrized coal a.s a fuel for the.furnaces. Elaborate irista.llations have been made for pulverizing tne coal ar!d _ coriveyi16 i -c to the fur:waces. • Soon after the furnaces ·-:commenced .. to operate ·,Vi th :pulverized coal, large quanti ties O::f.' fine dust beg.::in to accumulate on the platforms over the fu:rna. ces, the. roof trusses, on the outside of the va.rious· pip·e ·line electric cables a.i.1.d even on the roofs of the buildings. Some of tha comi:,a.n:;.0s, becomin·g alarmed, requested the Bureau of ;Unes to rr.c1ke an investigation to ascertcliin the.· licibili ty of this dust to cause an explosion.· Nhi le conducting this inves ti ga ti on,· an explosion· occurr-2! d in a.nothe:2 nill ·,7hich caused he death of one man and severely burned t;io others. Eleven sc1nrcles of the dust (which for convenience has been termed "mill d.ust 11 ) from various locations in the different mill' buildings were taken and submitted to chemical analyses, microscopic examination and also to flame and explosion tests. From the chu,1ica.l analyses it was found that· the volatile matter in th..:: dusts xanged -from 6.3 per cent to 23,54 per cent, fixed carbon from 50.88 per cent to 67.08 per cent and ash from 32.29 per cent to 32.16 per centw

Dec 1, 1919

By A. W. Deurbrouck

This Bureau of Mines report describes the preparation characteristics of the significant coalbeds from which samples could be obtained in Upshur County, W. Va. One of the 14 samples collected was of metallurgical quality as received, 6 could be sufficiently upgraded to provide acceptable products, and 7 could not be upgraded to metallurgical quality because of their high sulfur contents.

Jan 1, 1967

By Miles B. Royert

Crude Minnesota taconite was charged in the Bureau of Mines experimental blast furnace so that smelting characteristics of such highly siliceous raw materials could be studied and smelting costs compared with those of a standard Mesabi ore. The Bureau recognized that the highly siliceous nature of the crude ore and its relatively low metallic content would be serious economic deterrents to commercial use of the raw taconite, but compensating factors would be low capital investment in production facilities, large tonnage available on short notice, high recoveries of iron, and low delivered cost. Crude taconite smelted readily in the experimental blast furnace. Coke consumption per ton of metallic product was very high, compared with the average established requirements for smelting normal grades of metalliferous raw materials. Slag rates were also inordinately high. Metal quality was erratic as to silicon, and sulfur contents were objectionably high.

Jan 1, 1961

By W. J. Fullerton

This paper is one of a series being prepared by the U. S. Bureau of Mines describing mining and milling methods and costs at cement-plant quarries throughout the United States, end deals directly with methods and costs at the quarry and mill of the North American Cement Corporation at Catskill, N. Y. The process of manufacturing cement is described only as far as the final grinding of the raw materials. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs may in many instances cause embarrassment to individual producers, as well as to the industry as a Whole. On the other hand, operating costs are essential to the technical discussion and study of methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding; of the scone of the cost tabulations may ensue.

Jan 1, 1931

By L. K. Weaver

The objective of this Bureau of Mines publication Is to present a nomograph that provides a fast, convenient method for estimating hydrocarbon lease bonus bids for offshore acreage in the Gulf of Mexico. Discounted cash flow analyses were computed from a model derived to show the costs necessary to explore, acquire, develop, produce, and abandon a 5,000-acre block of offshore acreage, and the estimated income from the sale of the hydrocarbons produced from the block. The range of the variables in the financial analyses used to construct the nomograph are prices of oil, $2.50 to $5.00; recoverable hydrocarbon reserves, 44,651,476 to 127,575,645 barrels; and discounted cash flow (DCF) rates of return, 5.0 to 57.2 percent. A total of 1,234 sets of DCF data were used to construct the nomograph. The range of bonus bids shown on the nomograph is from 2 to 90 million dollars ($400 to $18,000 per acre).

Jan 1, 1973

To develop a business case that promotes adoption of noise controls by reducing barriers to industry acceptance and enhancing drivers that foster their implementation. Background Over 75% of the U.S. mining workforce is exposed to hazardous noise, putting them at risk of noise-induced hearing loss (NIHL). Consequently, coal miners suffer high rates of hearing impairment that increase to 70%-90% by retirement age. To address the noise problem for coal miners, researchers from the National Institute for Occupational Safety and Health (NIOSH) first determined that the continuous mining machine (CMM) ranked first among machines associated with reported coal noise overexposures. Further studies found that most CMM noise is generated by three component systems on the machine: dust collection, cutting, and conveying. Of these systems, the on-board chain conveyor was found to be a dominant noise source. Noise generated by the conveying system was addressed through the development of a urethane-coated flight bar chain. The coated chain, shown in Figure 1, has demonstrated an 8-hour time-weighted average (TWA) reduction of operator exposure by 3 dB(A). It has since been accepted by the Mine Safety and Health Administration (MSHA) as a "technologically achievable" noise control for CMM operators who are exposed to noise that exceeds the MSHA permissible exposure level. Having demonstrated the noise reduction performance of the coated chain, NIOSH has assembled information into a business case that can be used by operations considering adopting the chain at their worksite.

Dec 1, 2009

By M. E. Volin

The Ladd manganese deposits are in San Joaquin County, Calif., about 13 miles southwest of Tracy. The deposits are confined in two main areas of development, roughly about 1,700 feet apart horizontally, and known as the Ladd mine and Fabian mine, respectively. The deposits occur as interbedded lenses in the white cherts of the Franciscan formation. The ore minerals are bementite, rhodochrosite and psilomelane. As a part of the Bureau of Mines program of investigation and development of domestic mineral deposits, a development program was started. August 24, 1940, and completed on June 24, 1941. The Federal Geological Survey cooperated by mapping the geology and logging the drill cores. The program included road building, trenching, rehabilitating the mine workings, trenching underground excavation, sampling, and core drilling. The following pages mention the location, give a brief history, and note the physical features of +1-.1, district. Mine workings are sketched, the deposit is described and the plan of the project is noted. The work performed by the Bureau of Mines is explained in the concluding pages with a summary of the drill hole logs.

Jan 1, 1949

By Warren E. Morrison

This study was prepared in response to the need for a series of data that reflect the basic flow pattern of energy resources in the United States. To effectively measure and analyze energy,2 it is necessary to prepare balances that reflect both production and consumption, and the various forms energy resources take at different stages of utilization. Before energy can be measured it must also be put into a common unit. In this study the common unit us d is the British Thermal Unit (Btu). The ideal point to survey energy is at the stage of final ultimate use, representing the useful work derived from the interaction of energy inputs and the prime mover. Unfortunately this concept of efficient or useful work from energy output cannot readily be measured in the aggregate. With the present available official data, energy measurement can be carried to the point of calculation of net inputs of energy3 into the economy at various stages of utilization. However, preparation of energy balances, on a net basis is hampered by the fact that this can only be done for years when the censuses of Mineral Industries and Manufactures are taken, usually at 5-year intervals.

Jan 1, 1964

By John P. Capp

The feasibility of simultaneously burning several paths through a coalbed to develop a multiple path underground gasification system was investigated by the Bureau of Mines during two experiments, Boreholes were drilled through the overburden and into the coal and arranged in a circle approximately 50 feet from a central borehole. In the first experiment, in an area which had previously been hydraulically fractured,5 air was injected at the center borehole. The coal was ignited at the other boreholes and the fire fronts traveled toward the center, counter to the flow of air, to backward burn paths through the coalbed. Two paths were linked during the first 5 days of operation. The outlets of these two paths were throttled and air pressure was increased to maintain the flow of air, but no other linkages were made. Fourteen days after the two linkages these two paths were opened and gasification was carried on for 10 days, but with only moderate success. In an effort to overcome operating difficulties air was injected at the peripheral boreholes, and the gases were drawn off at the center borehole. Reversed flow operations continued for 12 days and two more paths linked. The heating value of the gas generally was higher than 100 British thermal units per standard cubic foot (B.t.u. per std. c.f.). Because only four of seven paths linked, however, the entire system could not be evaluated with respect to product-gas output and recovery of energy.

Jan 1, 1961

By Warren E. Morrison

This study was prepared in response to the need for a series of data that reflect the basic flow pattern of energy resources in the United States. To effectively measure and analyze energy,2 it is necessary to prepare balances that reflect both production and consumption, and the various forms energy resources take at different stages of utilization. Before energy can be measured it must also be put into a common unit. In this study the common unit used is the British Thermal Unit (Btu). The ideal point to survey energy is at the stage of final ultimate use, representing the useful work derived from the interaction of energy inputs and the prime mover. Unfortunately this concept of efficient or useful work from energy output cannot readily be measured in the aggregate. With the present available official data, energy measurement can be carried to the point of calculation of net inputs of energy3 into the economy at various stages of utilization. However, preparation of energy balances, on a net basis is hampered by the fact that this can only be done for years when the censuses of Mineral Industries and Manufactures are taken, usually at 5-year interval.

Jan 1, 1964

By E. G. King

Difficulty has been encountered in making thermodynamic calculations of metallurgical reactions involving interoxidic compounds of the ferroalloy elements because of the serious lack of most thermodynamic data for these substances. This Bureau of Mines report (the first of a planned series dealing with entropies of vanadates, tungstates, and molybdates) presents low-temperature heat-capacity data and entropy values at 298.15° K. for three crystalline sodium vanadates--metavanadate (NaV03), orthovanadate (Na3VO4), and pyro-vanadate (Na4V2O7). The results are combined with data for the constituent oxides and elements to obtain entropies of formation of the vanadates. Previous to this report only one vanadate had been studied Similarly, ammonium metavanadate.4/

Jan 1, 1961

By G. S. Scott, G. W. Jones

"INTRODUCTION An important phase of the accident-preventing program of the Bureau Mines is the determination of the explosion hazards of various combustible gases, vapors, and liquids encountered in mining and allied industries and the development of methods of eliminating or mitigating them.Recently, isobutane has become a commercially important raw material in the production of aviation gasoline by the alkylation process. 4/ in which isoparaffins are combined with olefins to give higher molecular weight compounds of branched-chain structure.Because of the anticipated commercial importance of isobutane in industry, it has been deemed necessary to study and determine its general explosion haz¬ards. This report gives its limits of inflammability, minimum ignition temper¬atures, and the amounts of nitrogen and carbon dioxide required to render isobutane-air mixtures noninflammable."

Jun 1, 1947

Background Carbon monoxide (CO) is an odorless, colorless gas that can cause illness and death by asphyxiation. Although the toxicity of CO is understood, CO exposure can occur from unrecognized sources. On April 2, 2000, a couple and their newborn infant were poisoned by CO migrating through the ground from blasting at a nearby coal strip mine into their home near Kittanning, Armstrong County, PA. They were treated at the hospital and diagnosed with CO poisoning. The infant had a carboxyhemoglobin level of 31%, the father 28%, and the mother 17%. Carboxyhemoglobin is the compound formed in the blood when CO is breathed. Persons not exposed to CO have carboxyhemoglobin levels of 0.3%-0.7%, and cigarette smokers have levels of up to 9%. Following release from the hospital, the family installed a CO detector in the basement of their home with the help of the local fire department. This Technology News briefly describes this incident to help increase awareness of the problem. It is discussed in more detail by Eltschlager et al. [2001]. Figure 1 shows the coal strip mine believed to have generated the CO. The initial suspect for the source of the CO was the furnace in the house. Only later did it become apparent that blasting at the nearby strip mine might be the culprit. A State investigation concluded that CO had migrated approximately 500ft from the blast, through the ground, and into the home. Figure 2 shows the locations and order of blasts at the mine. Initially, the mine did not plan to blast. Overburden generally consisted of weathered shale that could be dug without blasting. However, the mine decided to blast when hard sandstone that could not be dug out was encountered within 3 ft of the coal top. The blasting was intended to break up the sandstone. Blasting was done using bulk ammonium nitrate-fuel oil (ANFO) in 6.25-in holes 25-30 ft deep on a 16-ft by 16-ft pattern, with charge weights ranging from 17 to 170 lb. The closest blast to the home was 430 ft on April 17, 2000. The distance from the home to the blast area on the day when CO was first reported (March 31, 2000) was 500 ft. Twenty blasts were detonated at the mine between March 7, 2000, and April 20,2000. The blaster was careful to prevent fly rock since another home was only 150 ft away and a garage was 50 ft away. The quantity of explosive used in the blasts was sufficient to break the sandstone, but was less than would normally be used to blast overburden. The holes were typically one-third explosive and two-thirds stemming, with powder factors averaging 0.43 lb/yd3. Additionally, the muck was not immediately excavated after each blast. The heavy confinement on the explosive acted to prevent the typical release of blasting fumes into the atmosphere. Instances of CO migrating from blasts into homes have occurred before, but generally the distances involved were under 150 ft. It is believed that the blast design contributed to the confinement of CO in the ground, and discontinuities in the ground strata facilitated migration toward the residence. Upon inspection of the blast pitwall, a regular system of joints was observed. These joints are oriented roughly from the blast pit toward the house (figures 3-4).Blast-generated CO appears to have been driven into the joint system, displacing the air. When the joint system was saturated, the next succeeding blast pushed the CO into an uncased well next to the house (a high level of CO has been measured in the well shortly after a blast). From there, the CO entered the French drain system and then the basement of the house. The joints are vertical cracks through rock layers that occur on a regular spacing (figure 3). They are most common near valley slopes and are caused when valley walls converge as the stream cuts down through the rock layers. Often called hill seams, they roughly parallel the valley walls, but can curve and split, creating a pathway for gas movement (figure 5). These fractures are often encountered when underground mining proceeds close to outcrop. The system of fractures at the Kittanning blast pit was well developed and provided a path for transmission of CO both through the sandstone and up and through the overlying shales. Blasting engineers should be able to distinguish naturally occurring fractures from blast fractures and note the frequency, development, and orientation of the hill seams and their proximity to occupied houses. The limits of transmission of

May 1, 2001

By C. P. Bowie

[Frequent accidents in the transportation and. handling off petroleum and its more volatile products, serve as a reminder that this is indeed a hazardous undertaking and should always be conducted with due caution. On October 4, 1920, vapors in the held of the British tanks steamer G. R, Crowe became ignited and, caused an explosion which, it is reported, killed 5 men, injured. 40 others and endangered the lives of some 300 more. On November 10, 1920 the Morgan, Line freighter El Mundo was almost totally sot destroyed in New York harbor by fire caused by an explosion of gases in a fuel-oil tank. These two disastrous explosions emu emphasize the ever- present danger attending the use of petroleum products. This is also shown by the frequent occurrence of minor fires and explosions, caused by careless handling of baseline, which result in loss of life or serious injury to railroad employees, to oil-tank drivers, and to individuals in various walls of life. Statistics indicate that the lighter cuts of petroleum products, because of fire hazards, are dangerous, and are so considered by the railroad and other transportation companies. According o the Bureau of Explosives (Bar-eau of Explosives Report No. 13 p. 7) during 1919 transportation of gasoline in the United States resulted in 172 accidents, causing 2 deaths and 31 injuries, and a property loss to the extent of $687,966. Among the causes of ignition, an open light in the vicinity of the container stands out most prominently.]

Jan 1, 1920

By Erik Bengtsson

Phenol was discovered in coal tar by Runge (1)1/ in 1834 and was isolated (2) in 1841 as pure phenol by distilling the tar, extracting with caustic soda, acidifying the extract, and fractionating the tar acids. Later, o-cresol was isolated (3) through careful fractional distillation of the tar-acid mixture. The m-and p-cresols distilled within a boiling range of about 1.50 c. and had to be separated by other means. Raschig (4) fractionated the tar-acid mixture to obtain pure o-cresol, sulfonated the mixture of m-and p-cresols, and treated the cresol-sulfonic acids with superheated steam at 1200 to 1300 c. to hydrolyze the m-cresol sulfonic acid, the p-isomer was not affected at that temperature. He also attempted to make use of the different crystallizabilities of the m-and p-cresol sulfonic acids (5). When treated with sodium bisulfate and sodium pyro-sulfate at 100° to 110° C. or with sulfuric acid (90/0) at 20° C., only the m-cresol was sulfonated (6). Hoffman-La Roche (7) treated the meta-para mixture with concentrated sulfuric acid at 40° to 100° C., when m-cresol and part of the p-cresol was sulfonated, and precipitated the m-cresol sulfonic add by diluting with water. The same sort of separation may be carried out by means of 80 percent sulfuric acid at 35° C. and 35 mm pressure (8).

Jan 1, 1950

By H. B. Brunot

A complete list of permissible mine equipment , tested and approved by the Bureau of Mines previous to January 1 , 1947 , was published as Information Circular 7432.27 A list of permissible mine equipment tested and approved by the Bureau of Mines during the calendar year 1947 was published as Information Circular 7465.3/ The present list supplements Information Circular 7432 and includes all of the equipment approved during the calendar years 1947 , 1948 , and 1949. It therefore supersedes Information Circular 7465. The list also includes an appendix ( No. 2 ) giving the symbol that must be used by every cable manufacturer in marking trailing cables that have passed the test for flame resistance as stated in the amendment of October 21 , 1947 , to Schedule 2E . The items are numbered to indicate the consecutive order in which each type of machine or device was approved in its particular classification . Thus , Information Circular 7432 showed six air compressors on the active list ; five additional compressors , Nos . 7 to 11 , inclusive , in this category were approved during 1947 , 1948 , and 1949 . Several items that were listed in Information Circular 7432 have been repeated in this circular where it was necessary to show that approvals of such equipment were extended to cover an additional voltage rating or other changes . Equipment listed in these circulars is approved by the Bureau of Mines only when found , upon inspection and test , to comply with minimum standards of safety as outlined in schedules prepared on the basis of many years of experience in dealing with safety problems of the coal -mining industry . The use of such equipment in mines known to be gassy , as well as in those that may become so , is earnestly recommended in the interest of safety . This circular is published so that the industry may be kept informed as to the many types of machines , devices , and lamps that are available for reducing explosion and other hazards incident to coal mining . This circular and Information Circular 7432 give the complete list of permissible mine equipment that is available under the various classifications .

May 1, 1950

This paper on. the physical and chemical properties of crude oils from California fields is one of a series of reports on the oil-producing districts of the United States., The paper includes a short discussion of results, tabular data, and individual analyses of eight California crudes. Analyses of other crude oils from California have been published in Reports, of Investigations 2595,3/ 2608,4/ and 28465/. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting samples was facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1931