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By Charles L. Kimbell

This study is intended to serve three roles. First, it is an extension of the previous works under the same title that have been the overview and summary chapter of the international volume of Minerals Yearbook since the inception of that volume. Following the traditional format of past chapters, the basic statistical presentations herein deal chiefly with 1989, and in some instances with 1988, the latter only because more recent, comprehensive global statistics for 1989 are simply not yet available owing to delayed data collection and processing in some countries and continued governmental suppression of data in others. The second role of this study is to provide an update to the coverage of events impacting on the world's mineral industry that have occurred between the end of 1989 and the preparation of this study. Inclusion of this update is almost essential because of the potential effect of some of these events on global mineral industry activities.

Jan 1, 1992

By L. W. Scott, T. H. Dubaniewicz, F. T. Duda, P. G. Kovalchik

Recent research conducted by NIOSH, Pittsburgh Research Laboratory showed that electrical current levels permitted under parent regulations may not limit cable temperatures to less than 90 °C in reeled trailing cables. Reeled cables, tightly wrapped with many turns, ell carrying current in an enclosed space, can become overheated due to poor heat transfer. This overheating can cause the cable insulation to soften and become easily damaged. The damaged insulation reduces the life of the cable and can lead to shock, electrocution, and mine foes. This paper describes a method of measuring the conductor temperature of untie trailing cables during no anal operation. The temperature is measured using a 50/175 micrometer Graded Index Multimode Optical Fiber located in the center of the metallic conductors. Distributed temperature measurements arc made using an Optical Time Domain Reflectometer (OTDR). This system is capable of measuring temperature with an accuracy of plus or minus one degree centigrade over a length of 4 km at 1-m intervals. With this unique way of measuring temperature, tests can be conducted simulating actual mine conditions and provide important data to allow MSHA's Approval and Certification Center to develop approval criteria for cyclically rated reeled machines.

The coal deposits in Alaska occur in several major coal fields or basins. The deposits underlie about a quarter of the state, an area larger than Montana. Approximately 60 percent of the coal is bituminous and 40 percent is subbituminous. Less than one percent is lignite or anthracite. Although known coal reserves are estimated at only 6.1 billion tons (about 1.25 percent of U.S. reserves), estimates place the hypothetical reserves at 5.5 trillion tons and the identified reserves at 170 billion tons. The differences are due to limited exploration programs within the state. Conditions affecting mining and reclamation are unique to Alaska because of its extreme northern latitude. For example, permafrost occurs in about 75 percent of the state; tundra vegetation occupies vast treeless regions; and the climate is characterized by extremely cold winter weather and a short summer season. In addition, hydrologic conditions are considerably different from those in other states; major streams fed by silt-laden glacial melt water contain greater concentrations of natural sediment than the effluent discharge limits permitted by federal regulations. Also, some coal field locations are subject to potentially high seismic risk. These factors make coal mining and reclamation in Alaska more difficult than in other states. Alaska's program to regulate surface coal mining was approved May 2,1983. The Abandoned Mine Lands program was approved December 23,1983.

Jan 1, 1992

By R. Sainath, Wils L. Cooley

Continuous monitoring of ground bed resistance is essential to insure a low-resistance path for fault currents, lightning strokes, and electrostatic discharges. This paper explains the salient features of the continuous ground bed monitor and its applications. The importance of a low-resistance path to ground is highlighted. Sample readings obtained with the ground bed monitor are included, and typical applications of this instrument are illustrated. This effort was supported by the U.S. Department of Interior's Bureau of Mines under USBM grant G0144138.

Jan 1, 1979

By Sean Gallagher, William S. Marras, Alan S. Litsky, Deborah Burr

Background. There is currently little information regarding factors associated with specific modes of motion segment failure using a fatigue failure model. Methods. Thirty-six human lumbar motion segments were fatigue tested using spinal compressive and shear loads that simulated lifting a 9 kg weight in three torso flexion angles (0, 22.5, and 45). Twenty-five segments failed via fatigue prior to the 10,000 cycle maximum. These specimens were visually inspected and dissected so that the mode(s) of failure could be determined.Failure modes included endplate fractures (classified into nine varieties), vertebral body fractures, and/or zygapophysial joint disruption. Logistic regression analyses were performed to determine whether certain morphometric variables, amount of motion segment flexion, disk degeneration scores, and/or loading characteristics were associated with the occurrence of specific failure modes. Findings. Results indicated that stellate endplate fractures were associated with increased posterior shear forces (P < 0.05) and less degenerated discs (P < 0.01). Fractures running laterally across the endplate were associated with motion segments having larger volumes (P < 0.01). Endplate depression was more common in smaller specimens (P < 0.01), as well as those experiencing increased posterior shear force (P < 0.05). Zygapophysial joint damage was more likely to occur in a neutral posture (P < 0.01).Interpretation. These results suggest that prediction of failure modes (e.g., specific endplate fracture patterns) may be possible (atleast for older specimens)

By Lloyd A. Morley, Alan M. Christman

General An important part of any mine power distribution system is its con¬nection to earth or ground. The grounding network serves to protect men and machinery from the hazards associated with electrical equipment which is operating improperly. Since the mine site is determined by the location of the rock or mineral to be extracted, the conditions required for the installation of an adequate grounding system are not always easily met. If annual rainfall is low or soil resistivity is high, an extensive array of buried metallic conductors may be necessary to assure a low-resistance connec¬tion to earth. Measurement of soil parameters can be made before the construction of a grounding grid is begun, and the configuration of a metallic network, which will yield the desired values of earth resistance and potential gradient, thereby ascertained. Proper design at the time the ground bed is installed will save much time and expense in later years. Ground conductors extend from the buried grid to each piece of mo¬bile and portable equipment via overhead lines or multi-conductor cables. In this fashion all machine frames are referenced to the same potential as the grounding medium. Protective circuitry must be installed to monitor\current flow in the ground conductors or the potential drop across the neutral grounding resistor, which is placed between the grounding grid and the neutral point on the distribution transformer secondary. When properly co-ordinated and used in conjunction with a low-resistance

Jan 1, 1976

By E. J. HOFFMAN, L. A. SCHOLL, J. c. W. FRAZER

The danger from coal dust in mines has been thoroughly demon- strated by experiment, and consequently the study of the inflam- mability of coal dust suspended in air, that is, the readiness with which a cloud of coal dust inflames, is of decided importance to those engaged in coal mining. Much knowledge has been gained from the work done in the large galleries constructed at official and semiofficial stations in this country and abroad, but the study of the coal-dust problem in these galleries requires so much time and is so costly that there is need of a reliable laboratory method for obtaining a classi- fication of the great variety of dusts that occur in mines. The investigation described in this paper was an attempt to devise such a method. It was a preliminary investigation, and work in the same direction is being continued by the Bureau of Mines. As Mr. Frazer has severed his connection with the bureau, it is deemed advisable to publish the results of his study substantially as he prepared them, with little attempt to draw conclusions or to show the bearing of the results on other studies now in progress. The results of these studies and a full discussion of the significance of the laboratory investiga- tions will be published in future reports of the Bureau of Mines. The reader should remember that any laboratory method, since it involves conditions that differ so greatly from those of actual mining, should be thoroughly tested, and the results obtained by it should be confirmed by experiments conducted on a scale simulating mining conditions before final conclusions are drawn. The need of a laboratory method has long been felt, and several investigators have devised apparatus and methods. The work done by Vital, Holtzwart and Von Meyer, Bedson and Widdas, Le Chate- lier, and that of the British Coal Dust Commission is of great interest in this connection. Bureau of Mines Bulletin 20 contains a sum-

Jan 1, 1913

To develop and design a bit that will rapidly drill smooth and precise instrumentation holes in soft rock. Approach Use a one-piece bit made by combining a drag bit and a diamond bit. Because a smooth-walled borehole with a precise diameter is needed for borehole pressure cells (BPC) and other borehole instruments, a diamond bit is usually used. However, diamond bit drilling is slow, and the bit will tend to bind when squeezing ground is encountered. On the other hand, the drag bit will cut faster, but the walls of the drill hole will be rough and the diameter will not be as precise. The combination will provide a bit which penetrates as rapidly as a drag bit, but retains the smooth-wall and precise borehole diameter of a diamond bit. How It Works A three-foot-length of EW-size drill rod is centered in a diamond bit by welding it to three equally-positioned spacers at each end of the bit. A drag bit is attached to the EW rod with a standard EW-to-drag bit adapter as shown in the diagram. Three equally-spaced diamond inserts are set to the desired hole size and welded to the diamond bit barrel behind the crown. These inserts increase the smoothness and precision of the hole by cut-ting away any hole closure. Three equally-spaced shims are set approximately 0.020-inch under the overall insert diameter size and welded to the rear of the diamond bit barrel. The combination bit should be used on a diamond drill with either water, mist or air as the coolant.

Jan 1, 1982

By D. Harrington, M. W. Von Bernewitz

"The erection of barricades by men who are shut off from escape in mines at time of fire or after an explosion has been consistently advocated by the United States Bureau of Mines. Largely through the publicity given by the bureau to this excellent type of emergency safety endeavor, several hundred lives have been saved during the past 20 years. One of the earliest instances of barricading in the United States of which there is fairly complete record was in connection with the Cherry mine fire in Illinois in 1909; in this fire 259 lives were lost, but 20 men were saved by two barricades and were brought safely to the surface after seven days. In another coal-mine fire, followed later. on by an explosion, at Delagua, Colo., in 1910, 79 lives were lost, but 18 men saved themselves by erecting canvas brattices or barricades; the miners in one barricade were removed safely after five hours and those in another after 21 hours. In 1911, after an explosion in a coal mine at Briceville, Tenn., in which 84 lives were lost, five persons were brought out alive after 58 hours behind a barricade. Twenty hours after an explosion in which 73 were killed at McCurtain, Okla., in 1912, 13 men were taken out alive and one dead from behind a barricade or partition constructed of canvas. In 1914, after an explosion at Eccles, W. Va., in which 181 were killed, 35 men barricaded themselves in one place and after four hours were brought to the surface alive; this barricade was also of canvas. In 1915, 112 men were killed in an explosion at Layland, W. Va., but two groups of men, 47 in all, were able to barricade themselves; after four days 46 men were rescued alive, but one man was dead. In 1915, an explosion at Boomer, W. Va., killed 23, but 27 others barricaded themselves in one place and after seven hours came out alive. All of the foregoing instances of barricading were in coal mines. In 1917 there were three cases of barricading in a Montana metal-mine fire (the North Butte) during which 163 lives were lost. One of the barricades, sheltering 19 men, failed because the region barricaded was in porous broken ground through which the poisonous gases seeped and killed the entire group. From another of the barricades, engineered by an assistant foreman, 8 men were taken out, 6 uncon¬scious and 2 dead, 50 hours after the fire started. The 6 unconscious men lived, out the assistant foreman who directed the men was one of the 2 who had died. In the third case of barricading in this metal-mine fire,,men, also led by an assistant foreman, kept themselves closed in for about b6 hours and then broke barricade or bulkhead, 25 oing in one direction to safety, and 4, including the assistant foreman, going in another direction to death from poisonous gases. There have been a number of other cases of barricading, some successful and others a failure. Probably the worst failure was that in the argonaut (gold) mine fire in California in 1922; all of a group of 46 miners behind a barricade were found dead when reached after 21 days."

Apr 1, 1933

By Hans M. Cassel

The specific objective of research presented in this report was clarifi- cation of physicochemical fundamentals of the mechanism of dust explosions. The equipment, techniques (chiefly photographic), and dusts (chiefly graphite and light metals) employed are described. From behavior of individual par- ticles, conclusions are drawn as to their cooperative function in ignition and combustion of dust clouds. Results are interpreted using thermal theory as accepted for combustible gas mixtures. Radiative transfer across the flame front, as a characteristic of dust flames, is given particular atten- tion. Related studies by other investigators are discussed.

Jan 1, 1964

By I. AITKENS

Tourmalines are among the most beautiful of all the semiprecious stones, and are unsurpassed even by corundum in variety of hue. The stones most suited to jewelry purposes are those comparatively free from iron. One reason for the fact that the tourmaline has advanced rapidly in public favor in this country is that it is found in California in great profusion and of extraordinary quality. The superb green and especially the pink crystals found at Pala and Mesa Grande in San Diego County, Calif., are deemed superior to tourmalines from all other localities.

Nov 1, 1931

By Fred N. Kissell

The U.S. Bureau of Mines was established in1910 to reduce .the high accident rate in the nation&apos;s coalmines. For 85 years, it conducted a wide variety of tasks related to mining before it was abolished in 1995. The BOM had many technology transfer successes in its lifetime, including more than a dozen "R&D100" awards. This essay identifies and discusses five "transfer factors" that can explain the success (or failure) of many Bureau of Mines projects. These five factors are termed "pressure, pitfalls, path, price, and profit."

By M. Townsend, E. L. Petsonk, B. Fedders, M. Niggemeyer, H. Abrons, E. Daniloff, J. Griffin, K. Kinsley

In certain populations, nonspecific airway hyperreactivity (HR) is associated with increased respiratory symptoms and decreased lung function. We analyzed standardized pulmonary symptom questionnaires and pre-shift spirometry with methacholine inhalation challenge (Chatham, M. et al, Chest 82: 15) on 228 control workers (C) with no known exposure to occupational hazards, and 200 underground bituminous coal miners (M). M and c were similar in age, height, sex, and smoking status. HR (defined as >15% fall in FEVI after up to 5 vital capacity breaths of 25mg% methacholine) was found in 25% of M and 28% of C (NS). M showed higher% predicted FEVI (%PFEV) than c (M 107%, C 104%*). 28% of current smokers showed HR versus 22% of never smokers (NS). Current smokers showed reduced %PFEV but were not different from lifelong non-smokers regarding prevalence of HR. Subjects with HR showed reduced %PFEV, (HR 101%, not HR 107%*) but M and c with HR showed similar reductions. M had more dyspnea and chronic cough than c*. Hyperreactivity was associated with increased symptoms in controls but not miners. In our study, the prevalence of HR in coal miners was similar to nonminers, and did not explain miners' respiratory symptoms. * P < 0.05

Jan 1, 1989

By A. A. Afshari, D. G. Frazer, C. F. Stanley

"INTRODUCTIONThe primary function of the lung, i.e. gas exchange, occurs in peripheral units termed alveoli• Diagnosis of lung dysfunction ls therefore dependent on techniques to evaluate the status of the peripheral airways. Since these airways and alveoli are very small, it is difficult to determine directly how they function or how the function is changing due to disease. Yet this unde1·standing is critical to the design of instrumentation to detect early changes in lung function due to disease.An interesting hypothesis describing one aspect of small airway function has been proposed by Frazer (1) as gas trapping due to the formation of menisci in the airways. An additional study (2) proposes that the breaking and possibly the formation of these menisci could generate lung sounds, i.e. crackles. These lung sounds were recorded by placing a microphone at the trachea of an excised rat lung. The lung was degassed and then inflated and deflated. At points along the path of inflation, lung sounds were recorded. However, determination of the origin of the sounds was not attempted due to the difficulties induced by contacting the lung st1rface with a microphone.The purpose of this paper is to describe a non-contacting, whole field technique to monitor and describe the movements of the lung surface during inflation - deflation cycles.HOLOGRAPHIC INTERFEROMETRYHolographic interferometry is a full field, non-contacting and non-destructive technique that measures deformations of an object with a sensitivity in the order of the wavelength of light. A laser beam is split, with one beam reflected from an object and the other used as a reference beam. Both beams combine to produce a hologram of the object on a photographic plate. The process utilizes the concepts of interference, i.e. the two wave amplitudes will add at the points where the difference in optical path lengths over the exposure period is zero or a whole number of wavelengths and will subtract at other points."

Jan 1, 1989

The notion of wayfinding, as conceptualized by planners, geographers, and psychologists, denotes the ability of an individual to move from one point to another through physical space. In order to achieve this movement, a person relies on a cognitive map of spatial representations [Passini 1984]. Which features of this cognitive mapping will be stressed depend, in part, on the researcher&apos;s perspective. A planner, for instance, would tend to emphasize the effect of physical structures on mobility. A psychologist, on the other hand, might focus on individual differences in how human minds encompass and represent physical space [Evans et al. 1984]. There is yet another dimension to wayfinding that needs consideration, and it rests upon the idea that reality, as experienced by human beings, is mediated: "[People] have preselected and preinterpreted this world by a series of commonsense constructs ... which help them find their bearings in their natural and socio-cultural environment and to come to terms with it" [Schutz 1967]. These "common sense constructs" are arrived at socially and constitute the agreed-upon schemas that guide people&apos;s everyday activities. According to this principle, cognition is governed by some nonlogical factors that reflect not only individual procedures but collective ones as well. These group strategies, which are shaped by shared rules and values, influence "the information gathered, the ways it is processed, the inferences that are drawn, the options that are being considered, and those that are finally chosen" [Etzioni 1992]. From this perspective, cognitive maps, rather than being individual-centered templates of environmental images [Rovine and Weisman 1989] or representations of spatial relationships [Evans 1980], are partially group-centered schematic processes. As such, they are subject to reinterpretation, revision, and outside intervention [Kaplan and Kaplan 1982]. As intermediaries between the environment and behavior, cognitive maps serve as bases for decision-making. Traditionally, it has been assumed that good maps facilitate correct decisions, which in turn leads to optimal performance during wayfinding [Hunt 1984]. Given the argument that there is a social (non¬cognitive) facet to cognitive mapping, however, this image of a cognitive map as some sort of static reference construct that motivates individual action is too narrow and mechanistic. If cognition involves less a knowledge of the environ¬ment than it does the process of "giving it meaning through imposing an order on it" [Rapoport 1976], then wayfinding behavior is not j ust a function of setting and individual differences, but is also a function of one&apos;s "normative-affective" structure [Etzioni 1992]. Rapoport [1976] used such an assumption as the base for a set of hypotheses about the connection between "external demands" and "organismic factors." One significant assertion deriving from Rapoport&apos;s ideas is that environmental

Jan 1, 2000

By John W. Frey

This paper presents one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of Persia has been prepared from the best available information in Washington but is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers , to whom it is being referred through the courtesy of the Department of State .

Nov 1, 1929

By E. P. Youngman

Prior to 1854 the provincial legislatures in Austria enacted their own mining laws. The confusion that resulted from the existence of different codes when mining began to be conducted by modern methods forced the drafting of a law to cover all mining operations of the country. Such a general law (allegemines österreichisches Berggesetz) came into effect May 23, 1854, in the old monarchy, with the exception of Hungary, which had its own special laws. This general law of 1854 is still the basic mining law for Austria, although it has been amended and supplemented by a mumber of acts.

Nov 1, 1931

By George J. Carter, George H. Todd, Hal J. Kelly

In July 1956, the Bureau of Mines and the J. R. Simplot Co. participated in evaluating and beneficiating drill-hole samples from the Bovill, Idaho, clay-silica deposit and in tests of the beneficiated products. The geology, mineralogy, beneficiation, and potential uses of the clay and quartz fractions of the Bovill deposit are described. Test work showed that a filler-grade clay having an apparent spectral reflectance of 78 percent can be made by bleaching, and by removing some of the submicron-size particles. A quartz product suitable for the manufacture of glass containers can also be made.

Dec 1, 1963

By Wallace R. McCord, William E. Eckard

This report presents a detailed lithologic description of the Big Lime, Keener, Big Injun, Weir, and Berea horizons from a well cored in the Spruce Creek oilfield, Ritchie County, W. Va. Well logs and results of core analysis are also included. The information was obtained during the Bureau of Mines continuing technical evaluation of selected Appalachian area oil reservoirs for increased ultimate recovery. The lithologic study of these important West Virginia oil and gas producing horizons was made on a 4-inch-diameter core. Commercial oil production was obtained by the well owner after the Big Injun horizon was successfully hydraulically fractured.

Dec 1, 1963

By G. L. Barlett, J .. D. Barry

Supernatant media of dust-exposed pulmonary alveolar macrophages (PAMs) were inactive in assays for both Interleukin-1 and fibroblast growth factors (FGF). We have begun to evaluate several factors that may interfere with dust-PAM interactions. To determine the effect of sterilization on the activity of dusts, PAMs were exposed to autoclaved dust, heat-sterilized dust or to dust that had not been heated. Supernatants from the first two groups were inactive in the FGF assay, but supernatant from PAMs exposed to unheated dusts stimulated growth of lung fibroblasts. Recent data have revealed that freshly crushed mineral dusts possess labile free radicals that are absent in dust that has been stored for more than a few days. Suspensions .were prepared of a "stale" sample of anthracite dust 867 and of a freshly ground sample of the same dust. These suspensions were instilled intratracheally into guinea pigs under general anesthesia. Two, five or eight days later, PAMs were collected from the lungs by bronchoalveolar lavage, and the cells were counted. At two and five days after instillation, all lavage suspensions contained 70 to 85% PAMs, of which 5 to 18% contained phagocytized dust particles. On day eight there were again 80-84% PAMs in all suspensions, but in the presence of "fresh'" dust, 48% of PAMs. had phagocytized particles in comparison to 16% in the presence of '"stale'" dust. A similar experiment was performed in short-term cell culture. During 24 hours, >95%. of PAMs phagocytized dust particles, whether or not the dust was "stale" or '"fresh". Our studies are being extended to determine the effect of (1) removing surface oil contaminants by organic extraction and (2) suspending dusts without surfactant.

Jan 1, 1988