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Between 1985-1986, the Bureau of Mines reviewed the mining history and minerals information for areas in and near the San Isabel National Forest to appraise the mineral resources present and determine the types of deposits, and their location in the Forest, that could be mined economically if sufficient demand and metal prices existed. The two major metallic deposit-types that are of national mineral resource significance within the Forest are stockwork- molybdenum (with tungsten and tin) and carbonate-replacement zinc-lead-silver deposits. Historically, small gold placers, gold-quartz veins, silver-quartz veins, skarn iron and copper deposits, volcanogenic copper-zinc-precious metal deposits, and base- and precious-metal veins have been mined. Barite, carbonate rocks, gypsum, other non-metallic deposits, and pegmatites, have also been mined. Sand and gravel, present in large volumes, occurs along and has been mined outside the Forest along the upper Arkansas River valley. Turquoise and gemstones are present in small amounts and are of interest to collectors and jewelers. Geologically, sediment-hosted uranium and copper are present in small occurrences but no resources have been identified. Geothermal resources are related to the Rio Grande rift which parallels the central part of the Forest. Four hot spring areas are present - two of these are within the Forest. Because of the low power requirements of the region, and the presence of other generating facilities, these geothermal resources have had only limited local use. Evaluation of mine models that may be found in the region show that base-metal deposits require a high precious-metal component to be economic. Although molybdenum can be produced at economically competitive prices, there is little demand for the product. Capital costs to start new molybdenum mines would be very high and it is not likely that new mines will be put into production in the near future.

Jan 1, 1989

By Robert C. Johnson

Single crystal whiskers of ZrO2 and TiO2 were grown by solution and crystallization of these oxides in molten baths. Mixtures of Na2B407 and LiC1 were the most suitable growth media for zirconia. Sodium borate alone and Na2CO3 plus SiO2 were best suited for titania. The solubilities of zirconia and titania in molten sodium borate were determined, Whether zirconia whiskers were dendritic or nondendritic depended on the temperature used. The best single crystal whiskers were grown below 1,100° C. Titania whiskers always grew as single crystals. The tensile strengths of zirconia and titania whiskers were about 15,000 psi and 50,000 psi, respectively. Modulus of rupture was about 49,000 psi for zirconia whiskers and 75,000 psi for titania whiskers. Chemical analyses showed the zirconia and titania whiskers to be pure. The zirconia and titania whiskers were shown by X-ray analysis to be, respectively, baddeleyite and rutile.

Jan 1, 1965

By A. C. Fieldner, S. H. Katz

"Introduction.Recent experiments (Fieldner, A.C., Katz, S.H., Kinney, S.P., and Longfellow, E.S., Poisonous gas from carbon tetrachloride fire extinguishers, Jour. Franklin Institute, October, 1920, pp. 543-565), by the Bureau of Mines have shown that carbon tetrachloride extinguisher liquids when applied to fires produce small quantities of irritating and poisonous gases which may be dangerous in very closely confined spaces where conditions are such that the user can not escape without breathing the fumes. The results of the experiments have been confirmed in an independent investigation by the Underwriters Laboratories (Nuckalls, A.H., Corrosive action and products formed when carbon tetrachloride extinguisher liquids are applied to fires, Nat. Fire Protection Assoc. Quarterly, vol. 14, January, 1921, pp. 221-236) who conducted similar experiments for the purpose of determining the corrosive action of these fumes on metals. Both investigations showed that carbon tetrachloride vapor, hydrochloric acid gas, and phosgene were produced in addition to the ordinary products of combustion, such as smoke, carbon monoxide and carbon dioxide. The Bureau of Mines' tests were made by applying a one-quart extinguisher to a wood fire of excelsior in a gas-tight room of 1000 cubic foot capacity. The glass and metal construction of this chamber limited the experimental fire to very small dimensions. It was, therefore, deemed desirable to make a test on a larger scale in the entry of the Bureau's experimental mine in order to similate more nearly the practical use of carbon tetrachloride and other types of extinguishers in mines.Description of extinguishers.Two series of tests were made under identical conditions on different days. Commercial carbon tetrachloride extinguishers were used in the first series of tests and ""foamite firefoam"" extinguishers in the second series of tests."

Jun 1, 1921

By H. E. Perlee

Autoignition temperatures and limits of flammability of nine halogenated hydrocarbons in atmospheres of air, oxygen, and nitrogen tetroxide were measured in a modified standard autoignition apparatus and limit-of-flammability apparatus previously developed at the Bureau of Nines. Of the nine halogenated hydrocarbons investigates--bromochloromethane, bromotrifluoromethane, bromochlorodifluoromethane, 1,1,2-trichlorotrifluoroethane, 1-bromo-l-chloro-2,2,2-trifluoroethane, dibromodifluoromethane, l,2-dibromo-1,1,2,2-tetrafluoro-ethane, 1,1,1,3,3-pentachlorotrifluoropropane, and l-bromo-2,4-dichloro-1,1,2, 3,3,4-hexafluorobutane--two formed flammable mixtures with nitrogen tetroxide and six with oxygen; none formed flammable mixtures with air. Three of the halogenated hydrocarbons formed no flammable zones with any of the three oxidizing atmospheres. For those halogenated hydrocarbons that supported combustion in oxygen atmospheres, explosion pressures developed during constant-volume burning of mixtures near the middle of the flammable zone were observed to range from about 6 psig for dibromodifluoromethane to 158 psig for 1-bromo-1-chloro-2,2,2-trifluoroethane. In all cases, the calculated burning velocities of these mixtures were less than 8 in/sec.

Jan 1, 1966

By George R. Ingham

This paper is one of a buries being prepared by the Bureau of Mines on mining methods and costs at various mines in the United States, and is a description of the mining practice at Ajo, Ariz., where the New Cornelia Branch of the Phelps Dodge Corporation mines copper ore from an open pit, and operates a concentrator for the treatment of the ore thus mined. ACKNOWLEDGMENTS The authors wish to express their appreciation to M. Curley, manager of the New Cornelia Branch of the Phelps Dodge Corporation, for his review of this paper and permission to publish it. They also wish to acknowledge the assistance given by W. C. Lawson, assistant engineer, in the preparation of the paper.

Jan 1, 1932

By Fredrick L. Johnson

In 1984, at the request of the U.S. Forest Service, the U.5, Bureau of Mines began a study of the 94,370-acre Arc Dome study area (4-667) in order to appraise its mineral resources, The Bureau of Mines mapped and sampled mines, prospects, and mineralized sites in and near the area, The study area is located in the Toiyabe National Forest, about 54 mi north of Tonopah, Nye County, NV, It is estimated that over 500 claims have been staked in the study area since the mid-1800?s. In January 1986, there were 108 active mining claims completely inside and 59 on the boundary. Another 283 active claims were outside the study area but within 1 mi of the boundary, In addition to the large number of claims staked, exploration activity is also reflected by the almost 700 inactive workings that were found during field investigation.

Jan 1, 1989

By A. N. Fried

One of the important problems confronting oil producers in appraising the possibilities of secondary recovery in many California fields is the effect of viscosity on oil recovery by water flooding. In January 1954 there were 554 fields and/or pools, in the State, that produced 1 million barrels daily, and 138 of these pools produced approximately 267 thousand barrels daily of heavy crude oil having gravities below 200 API. Many of these fields are nearing the end of their primary economic life and still have high residual-oil saturations, a favorable factor in water flooding. The crux of the problem is whether or not enough oil can be recovered from these fields by water flooding to make the operation economically successful. Some experiments on the relationship between viscosity and oil recovery have been made by other investigators, but in most instances the viscosity of the oils used in the experiments was lower than the viscosity of the oils found in many of the heavy-oil fields in California. A study was undertaken, therefore, to determine the relationship between oil viscosity and recovery over a wider range of viscosities and to compare the experimental results with those predicted by theoretical calculations.

Jan 1, 1955

By A. B. Hooker

Many attempts have been made to develop methane detectors that will be safer and more accurate than the flame safety lamps used to detect methane in mines. The development has taken two general forms, namely: (1) Methane detectors, in which the evidence of methane depends entirely upon changes in the appearance of the detecting element, such as a flame or filament; (2) indicating methane detectors or those equipped with scales upon which the approximate percentage is definitely indicated. As an aid in the development of suitable detectors, the United States Bureau of Mines has assembled and published in its Schedule 8B a set of minimum requirements which tests and experience have shown desirable for methane detectors. Any manufacturer may submit his detector for inspection and tests leading to approval under this schedule.

Jan 1, 1930

By V. Vallyathan, Xianglin Shi, N. S. Dalai

While Cr(VI) is a known carcinogen, the underlying biochemical mechanism is still not fully understood (1). In a pioneering study Jennette (2) utilized electron spin resonance (ESR) spectroscopy to demonstrate that a long-lived Cr(V) species is generated during the reduction of Cr(VI) by microsomes in the presence of NADPH. Later Wetterhahn and co-workers (3, 4) showed that incubation of chromate with isolated rat liver mitochondria causes the reduction of Cr(VI), as well as the formation of a Cr(V) species. Analogous Cr(V) species have also been detected in the reduction of Cr(VI) by other cellular systems such as Hanserulla polymorphared (5) and blood cells (6, 7). All these as well as other studies (8-12) have suggested that this Cr(V) species plays a significant role in the mechanism of Cr(VI) toxicity. Thus far, however, the chemical structure of this dominant Cr(V) species formed in cellular systems has not been identified, and this observation provided an impetus for the present investigation. Another reason for undertaking this study was that some recent reports (10-16) suggest that hydroxyl ('OH) radicals may also play an important role in the mechanism of Cr(VI) toxicity. In particular, it has been shown that OH radicals are formed in reactions between Cr(V) species and H2O2 (13-16), and that the radical yield depends on the chemical structure of the Cr(V) species (15). For example, while Cr(V)-diol complexes efficiently generate OH radicals, another Cr(V) species, the tetraperoxochromate (CrO3/8) ion, does not (15). Thus in the present study, we focused our attention on the following: (a) structural identification of the Cr(V) species generated in the reduction of Cr(VI) by subcellular as well as cellular systems, using microsomes, mitochondria, and Escherichia coli; (b) possible detection of OH radical in the same systems since there is no earlier report of chromium-mediated generation of 'OH radicals in a cellular system; (c) possible involvement of molecular oxygen in chromium-related OH radical generation since a recent report (17) indicated that Cr(VI) mutagenesis is strongly oxygen dependent; and (d) elucidation of the mechanism of OH radical formation in these systems.

Mar 1, 1992

By Russell R. Trengrove

The Copper Canyon lead-zinc mine is in the Battle Mountain. District, Lander County, Nev. It was discovered in 1866 and mined for copper until 1935 and for copper and gold until l948, when the main production became lead-zinc ore. The rocks in the area are carboniferous (Pennsylvanian and Mississippian) sedimentaries that have been intruded by quartz monzonite of Mesozoic age. They have been intensely folded, faulted, and tilted. Lead-zinc ore occurs as sulfides disseminated along fractured zones in a conglomerate arid hornfels. Development was carried out by the Bureau of Mines in cooperation with the U. S. Geological Survey and comprised a study of the geology, making maps and. cross sections, and exploring the deposit by diamond drilling from underground. Eighteen holes were drilled, for a total of 2,594 feet. This report contains a brief history of the property and a description of mining methods and beneficiation of the ore, geology, ore deposits and drilling done by the Bureau of Mines. It also contains detailed analyses of the ore samples taken and logs of the holes drilled.

Jan 1, 1951

By L. C. IlsLey

A list of permissible mine equipment, tested and approved prior to Jan 1, 1937, was published in Bureau of Mines Information Circular 6942 • .ll The present list inc ludes additional equipment approved during the calendar yea r 1937. The ma terial has been listed und er the same. headings as th ose used. in Information Circular 6942. The number that appears at the beginning of each it em represents the number o f this type of ma.chine appr.oved including the machine in questi on; for instance, the miing ma.chine numbered 70 was the seventiet h co al cutting ma chine design for which approval has been isnued. All of the equipment listed represents new designs except that covered by the first item, that is, 57 under the • heading nLoading Machines and Conveyors. 11 This item covers the approval of the 500-volt design of a machine the 250-v olt design of which was approved on January 17, 1935. The system under wich these devices were tested permits the manu-. facturer., after his equipment has passed certain tests prescribed by the 'Ui"eau of Mines, to mark his equipment with a seal showing that it has been approved by the Bureau. These tests are designed to insure t hat equipments hav,e the minimum requirements for safety in use. The only object of the :Bureau in making such tests and publishing lists of permissible equipment is to help decrease the hazards of mining.

Apr 1, 1938

By E. Morrice

This report of the Federal Bureau of Mines presents a laboratory procedure, with the requisite equipment, for electrowinning ingot (liquid) cerium metal from a fused-fluoride bath, the metal purity being about 99.9 percent. Physicochemical studies, including bath properties and electrochemistry, are included, with a speculative model of the mechanisms involved. An historical review of the methods used for electrowinning misch metals and yttrim-group metals, as well as individual rare-earth metals, is presented. The electrolytic preparation of metal from fused salt and nonaqueous media is summarized, along with the unsuccessful attempts at depositing the metals from aqueous solutions.

Jan 1, 1961

By Michael D. Balen

This Bureau of Mines open file report is one in a series of reports written about the Valdez Creek Mining District (VCM D) as a result of the continuing Bureau of Mines mining district evaluation program. This report presents the results of order-of-magnitude mining feasibility studies. The mining feasibility studies were conducted for mineral deposit models that were based on real and hypothetical deposits that occur in the VCMD. A total of 6b mine models were developed for application to the mineral deposit models. The goal of the feasibility study was to determine the monetary value per unit of minable ore that would cause the simulated cash flow for each of 66 mine models to achieve certain pre-defined rates of return for the invested capital.

Jan 1, 2011

By Katherine Harding

Basic concepts of matrix algebra and manipulations of matrices are presented in such a way that little competence in mathematics is required. Examples are always included to illustrate concepts and techniques. The paper is divided into six sections. The first four sections are devoted to some of the more basic concepts of matrix algebra, whereas the last two sections are concerned with specific applications.

Jan 1, 1967

By G. M. Molinda

The U.S. Bureau of Mines conducted an investigation to determine the nature and frequency of coal mine roof failure beneath valleys. A mechanism for this failure and suggestions for controlling this problem are presented. Hazardous roof conditions identified in some mines were positively correlated with mining activities beneath stream valleys. Mine maps with overlays of unstable roof and locations of stream valleys show that 52 pct of the instances of all unstable roof in the surveyed mines occurred directly beneath the bottom-most part of the valley. The survey also showed that broad, flat-bottomed valleys were more likely to be sites of hazardous roof than narrow-bottomed valleys. Evidence of valley stress relief was found beneath several valleys in the form of bedding plane faults and low-angle thrust faults. This type of failure, previously believed to be only a shallow phenomena, was found at mining depths as great as 300 ft. In situ, horizontal stress measurements beneath a valley and the adjacent hillsides, confirmed valley stress relief. Numerical analysis of 13 valleys overlying one mine property showed the effect of the valley excavation on horizontal and vertical stress.

Jan 1, 2010

By John C. Edwards

The U.S. Bureau of Mines has constructed a smoke chamber and developed sensitivity tests for smoke detectors. Response of ionization-and optical-type commercially available smoke detectors have been investigated. Six smoke detectors were measured with respect to visually obscuring smoke characterized by a corresponding optical density for smoldering and flaming coal combustion in the smoke chamber. It was determined that for one type of ionization smoke detector the alarm time was nearly equivalent to that of an odor monitor's alarm for smoldering coal combustion experiments and earlier for flaming coal combustion experiments. The experiments showed that an average CO concentration of 5 ppm corresponded to an optical density of 0.022 m-l for smoldering and flaming coal combustion. Two of the commercially available ionization-type smoke detectors were more responsive to flaming than smoldering coal combustion at an optical density of 0.022 m-l, whereas the optical smoke detectors showed the opposite trend. The responsive characteristics of the detectors evaluated with respect to known smoke conditions in the smoke chamber shows their potential for use as mine fire sensors or part of a mine atmospheric monitoring system to improve mine safety.

Jan 1, 2010

By Mukund O. Gangal

A deep cutting continuous miner, HH456, was tested under production-mining conditions at the Joanne Mine, Rachel W. Va., for about 1 ½ years (226 production days). The miner was run in two modes: a low head-rpm, deep cutting and high rpm, shallow-cutting mode. These tests confirmed that deep cutting and slow cutter speed reduce respirable dust significantly under production mining conditions. Quantitative reductions in dust, in deep vs shallow cutting, were 73°; in return air and 63% at the operator's location. Production rate, (tons/shift), and bit consumption rate did not show any relationship to deep or shallow cutting. Reliability and maintainability of the miner were worse in deep cutting mode due to cutter drive shaft failures; the cutter shaft problem was solved through improved material and design. Excluding the cutter shaft repairs. maintainability war similar for deep and shallow cutting,

Jan 1, 1979

By H. W. Davis, W. W. Adams, O. E. Kiessling

"Current economic problems frequently have focused attention upon the lack of adequate quantitative information indicating the relationship between human effort and output in various branches of the mineral industry. With the exception of complete records covering coal mining, only scattered information on the units of human energy required to produce a unit of raw material is available for most of the important industrial minerals. Fortunately a virtually complete statistical record is available covering this phase of the iron-ore mining industry.For many years iron-ore mining companies, whose interest in safety work is well-known, have reported annual data on employment to be used in the compilation of accident statistics. These data on hours of labor and other detailed employment information have been correlated with the statistics on production also reported annually by producers. The outstanding trends shown by this composite record for the 10-year period 1923-32 are included in the following discussion, supplemented by a summary table that presents the principal statistical background of the study. 5The substantial reduction in the number of men needed to produce the annual iron-ore requirements of the United States, as shown strikingly in the graphs, illustrates that in iron-ore production improvements in technology have been consistently winning a battle over the difficulties of nature. In 1923, for example, 41,294 men working 107,551,244 hours were required to produce 69,351,442 gross tons of merchantable ore, equivalent to an average output of 0.645 ton per man-hour. In 1929, however, only 30,763 men working 77,111,686 hours 'zero required to produce 73,027,720 tons of merchantable ore, equivalent to an average output of 0.947 ton per man-hour. Thus, from 1923 to 1929 the average number of men working decreased 25.5 percent and the total man-hours worked 28.3 percent, while the average output per man-hour increased 46.8 percent and total merchantable ore production 5.3 percent."

Feb 1, 1935

By Michael R. Kennedy

This report describes the demonstration of longwall mining in a seam dipping 27 to 34'. Equipment was selected on the basis of capability, compatibility, and co t. Snowmass, Bureau of Mines, consultants and manufacturers were involved in the selection process. The equipment arrived in early 1981, prior to completion of development for the first panel; therefore, the equipment was operated on the surface for training. The surface training paid off with a fast, efficient installation and start-up of the face. The longwall equipment operated very well on the steep pitch with an average equipment downtime of 21.9[9]. Coal handling outby the face was a problem which caused an additional downtime of 19.5%. Development for the panels proved to be the major problem in the economics of longwall mining on a steeply dipping seam. During the first 9 months of operation the longwall averaged 71.9 TPMS and development averaged 0.6 TPMS for an overall average of 14.1 TPMS. Had mining continued, timing of development would have been another major problem. Monitoring of subsidence, pillar stability and shield loading was done in connection with mining, but little useful information was gained from the monitoring.

Jan 1, 1987

By W. L. O'Brien, E. A. Rowe

Electrorefined vanadium with additions of up to 5 percent by weight of yttrium, cerium , lanthanum , praseodymium, neodymium, and samarium was melted to ingots in a nonconsumable electrode arc in a helium atmosphere . The ingots were rolled into strips and evaluated for the effect of the alloying elements on hardness , tensile strength , ductility , recrystallization temperature , and microstructure . Except for samarium , average additions of alloying elements of 1 to 2 weight - percent resulted in the retention of 0.12 to 1.05 weight - percent in the alloys and reduced the ultimate tensile strength from about 48,000 to approximately 30,600 psi . The corresponding yield stress (0.2 percent offset ) was reduced from about 40,700 to approximately 20 , 200 psi . Diamond pyramid hardness (DPH) was reduced from 117 to an average of 62 kg /mm² . Increased malleability at room temperature resulted with yttrium and all rare - earth- metal additions , except samarium , particularly with more than 0.25 weight - percent additions . Decreasing oxygen contents corresponded with the changes noted in the mechanical properties of the alloys . The recrystallization temperature of electrorefined vanadium was reduced from approximately 950 ° to 800 ° C. Yttrium or a rare- earth metal content , except samarium , in excess of 0.1 weight - percent in vanadium produced a second phase suggestive of an eutectic which indicated a possible maximum solubility of less than 0.1 weight - percent for both room and elevated temperatures .

Jan 1, 1964