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Assess the technical feasibility of mining small and/or deeply buried frozen placer deposits from the surface through boreholes.

Jan 1, 1997

By Fred C. Turin, Jasinder S. Jaspal, Alan G. Mayton, William J. Wiehagen

This report describes serious injuries occurring to bulldozer operators working at U.S. coal, metal, and nonmetal mines. The period covered is 1988-97. The data were collected by the Mine Safety and Health Administration (MSHA). A total of 873 injury records are examined. These injuries resulted in 18 fatalities and 31,866 lost workdays. All of these injuries occurred to dozer operators while they were doing common production tasks. An injury classification system was developed to code the narrative information that describes the circumstances surrounding the injuries. Injury records are categorized by activity (task being done), incident result (what apparently happened to the dozer), and operator impact (how the operator was injured). Where information is available, contributing factors are identified. This classification system supplemented the standard injury/illness data classification system compiled by MSHA. The results of the study indicate that, from 1993 to 1997, the number of serious injuries to dozer operators declined by 30%. The reduction in serious injuries was accompanied by a decrease in days lost due to injury. Although the number of reported injuries has decreased, dozer operators being jolted and jarred accounts for the largest percentage (70% of the incidents) and severity (75% of the workdays lost) of serious injuries while operating the equipment. Vertical jars (while backing up the dozer) resulting in injury to the operator accounted for a sizable percentage of jolting and jarring injuries. Working near an edge carries significant risk for fatal injuries. Of 116 incidents where the dozer fell over an edge, rolled over, or fell into a hidden void, 14 (12%) resulted in fatal injuries. In cases where the dozer operator either jumped or was thrown out of the cab in a fall over or rollover, 7 out of 26 were killed. Overall, 80% of the fatalities occurred while working near an edge or hidden void or on a steep slope. Further reductions in injury risk will require more widespread use of seatbelts, field and laboratory research interventions to better assess the effect of alternative engineering (e.g., seat and seat suspension) designs to dampen or isolate the effects of shock and vibration, and continued focus on hazard awareness, recognition, and response.

Jan 4, 2001

By S. S. Peng

Successful longwall mining requires a good roof control. A good roof control implies that: (1) no excessive pressure is build up in the face powered supports, and (2) chain pillars are designed in such a way that panel entries are well protected and interactions between adjacent panels are minimized. A clear understanding of strata behavior around longwall panels due to face movement is, therefore, the foremost requirement for achieving better roof control. This dissertation is designed to analyze the effects of strata behavior on longwall panels due to the mining activities. The following topics are studied: (1) the weighting, phenomena and their effects on front abutments, and (2) the chain pillar stability and pillar design under various roof conditions. Three dimensional finite element analysis was employed. The effect of parameters such as overburden depth, mechanical properties of the immediate roof and main roof, panel width, and size of chain pillar on (t) and (2) were analyzed. Four typical models were utilized to simulate various phases of panel extraction under various combinations of the above parameters; model one is to simulate the beginning of panel mining; model two is to simulate the situation that longwall face has passed more than half of panel length; model three is to simulate the completion of panel production; and model four is to simulate the second panel mining. The following formulae have been developed by applying multiple regression model to analyze the finite clement results: (1) a formula that classifies the type of root strata at the face area. (2) formulae that predict the first weighting and periodic weighting lengths. (3) a formula for design of the chain pillar size. Case studies were performed to check the validity of the formulae proposed. Comparison of the formulae proposed for the chain pillar design with other formulae were also performed.

Jan 1, 1984

By Edward F. Courtney

Loss of life, loss of sight, crippling injuries, and property damage nearly always result from accidents involving explosives. The severity of such accidents has prompted lawmaking bodies to pass laws concerning the transportation, handling, and use of explosives; manufacturers of explosives publish manuals 'describing explosives and practical methods of handling then; and mining companies and others who use large quantities of explosives publish rules based on actual experience for the guidance of their employees. Careless storage of explosives by thoughtless or incompetent persons, particularly if they are left where children or saboteurs have access 'to them, has led to many serious accidents. Many contractors and mining operators who use explosives are extremely careless about storing them. It is the purpose of this paper to discuss the explosive-handling practices of a large western mining company, which are considered better than most.

Jan 1, 1946

By Gary A. Kingston

Chromium resources in the United States are estimated at 1.8 million tons of recoverable chromium contained in 22.5 million tons of chromite-bearing material. Additional resource is presumed existent in large, but as yet undetermined, quantities of material containing less than 10 percent Cr203. No domestic resources are being mined presently (1969). Excluding transportation charges to domestic consuming areas, the total 1.8 million tons of chromim is estimated to be available, in ore or concentrate, at costs up to $0.64 per pound; 63 percent of the total is available under $0.11 per pound; and 38 percent under $0.08 per pound. It is judged that transportation from the resource areas to the existing market centers would add nearly $0.05 to the cost of a pound of chromium contained in ore or concentrate. Technically effective beneficiation methods have been developed for much of the known domestic resource, and further development might reduce costs of processing these materials. However, at present, domestic chromium resources are noncompetitive with foreign sources.

Jan 1, 1970

By C. J. Chindgren, L. C. Bauerle, J. B. Rosenbaum

Modifications of the conventional method of preparing ductile vanadium metal by calcium reduction of V2 05 in a bomb were explored for clues to a more economical procedure . The modifications examined included ( 1 ) omitting the gas purge of the bomb ordinarily used for eliminating atmospheric nitrogen , (2 ) using low- grade vanadium feed materials , ( 3 ) using alternative reductants , such as aluminum , magnesium , and silicon , and reductant mixtures , and ( 4 ) bomb refining of aluminothermic metal produced in open- vessel reductions . The most promising modification appeared to be bomb refining , using calcium to purify vanadium metal -- of low aluminum but high oxygen content-- prepared by open- vessel aluminothermic reduction of vanadium pentoxide .

Jul 1, 1960

By Lung Cheng

The Bureau of Mines conducted laboratory tests to investigate the ease of frictional ingition with frozen (nonrotating) conical bits cutting into sandstone. The number of strikes with a new bit to obtain ignition of a combustible methane-air environment was measured. Tests were made with bits tipped with both tungsten carbide and steel at several bit attack angles (angle between bit axis and sandstone surface) and initial tip angles (included angle at the tip of the new bit). Carbide-tipped bits required more strikes for ingition than steel-tipped bits, by a factor of 7 to 10. With a carbide-tipped bit, the number of strikes for ingition increased by a factor of about 3 if the bit attack angle increased by 10° or if the initial tip angle decreased by 10°. During use, abrasive wear of the frozen bit caused a flat surface to form at the tip of the bit, thereby decreasing the tip angle. As the attack angle increased, however, the new bit involved a smaller wear-flat area whereby, abrasive wear was decreased.

Jan 1, 1987

By Douglas F. Scott

In 1981 the U.S. Bureau of Mines and U.S. Geological Survey conducted a mineral survey of the Pyramid RARE II area (No. 5023) covering 23,500 acres (9,500 ha) of E1 Dorado National Forest and 7,900 acres (3,200 ha) of the Lake Tahoe Basin Management Unit (fig. 1). The Bureau of Mines investigation did not reveal mineral deposits in the area. Samples taken from silicified and limonite-stained metasedimentary rocks and aplite dikes were void of precious or base metals or uranium. Placer samples from stream gravels contained no gold values. Molybdenite occurs in quartz stringers within quartz monzonite near Grass Lake, adjacent to the area; no extension; were found in the area.

Jan 1, 1982

By Launa G. Mallett, Jr. Brnich

Overview: The first step to emergency preparedness and maintaining a safe workplace is defining and analyzing hazards. Although all hazards should be addressed, resource limitations usually do not allow this to happen at one time. Risk assessment can be used to establish priorities so that the most dangerous situations are addressed first and those least likely to occur and least likely to cause major problems can be considered later. Purpose: This training package was developed to assist instructors as they (1) determine how to use risk assessment to improve safety preparedness and (2) present risk assessment concepts and tools to trainees. The concepts and tools presented here can be applied to any mine hazard.

Jul 1, 2003

By Fred N. Kissell

In This Chapter [Instruments available to measure methane in mines and tunnels Using a portable detector in both accessible and restricted spaces Machine-mounted monitors: placement and response time Calibration of catalytic detectors for different gases and Misinterpreting warning signs This chapter gives guidelines for methane measurement in mines and tunnels. The emphasis is on the measurement procedure and the interpretation of the measurement rather than on the instrument itself.] The failure to properly sample for methane is a major contributing factor to methane explosion risk. Sampling errors are most likely to occur at mines or tunnels where the presence of methane is not suspected or during nonroutine tasks at mines or tunnels known to have gas. More specific information on methane sampling at continuous miner sections is in Chapter 3. Chapters 4 and 5 discuss sampling at longwall sections, and Chapter 14 discusses sampling at tunnels. METHANE DETECTORS FOR MINING Many models of gas detectors are available to measure methane concentrations, as well as most of the other contaminant gases found in mines and tunnels. An example is the iTX Multi-Gas Monitor, a portable gas detector available from Industrial Scientific Corp., Oakdale, PA. This handheld instrument measures several gases simultaneously. The cost (2004) ranges from $1,300 to $2,200, depending on the number of gases measured. Similar instruments are available from other manufacturers. Most methane detectors used in mining use a catalytic heat of combustion sensor to detect methane and other combustible gases. These have been proven through many years of reliable operation. For detection of methane, proper operation of catalytic heat of combustion sensors

Jan 6, 2006

By H. Kim, R. W. Plummer, T. J. Stobbe, W. G. Jones

"Exposure to airborne dust in coal mines has caused respiratory disease in coal miners. The causal agent in these diseases remains unknown, although the minerals found in and around the coal seam have been implicated. Toxicological studies designed to establish the effect of different mineral combinations and concentrations are lacking because the mineral content of coal mine dust has not been defined. This paper reports the initial results of a study done to characterize the mineral content of the coal mine dust found in a mine in the Upper Freepott seam in Northern West Virginia. Coal mine dust samples were collected using 4- stage cassette impactors at nine locations in the mine. The samples were analyzed by an x-ray microdiffraction film technique supplemented by energy dispersive scanning electron microscopy. Primary size modes of about 17 to 20 micrometers from the samples collected at the haulageway and the returnside of the continuous miner were found. From the returnside of the roof bolter samples, a primary size mode of 12to15 micrometers was measured. The minerals found in high percentages were illite, kaolinite, quartz, and calcite. The distribution of minerals in inter· and intra- location samples showed wide variations. Trends in these variations are presented. Stobbe, T. J.; Plummer, R. W.; Kim, H.; Jones. W.: Characterization of coal mine dust. Appl. Ind. Hyg. 2:95· 100; 1986. IntroductionDisease-associated dusts in coal mine environments continue to afflict miners in today's modern mines. The relationship between exposure to coal mine dust and the development of various respiratory diseases has been well recognized; however, the reasons for variation in occurrence of these diseases among miners in different geographic areas,(1) rank of coal seams,(2-3) and jobs (4) remain uncertain. Several papers have reported on the causal agent in the development of these diseases. Davis (5) found that the percentage of the non-coal minerals present in the lungs of deceased miners increased as the level oi pneumoconiosis became more severe. Reisner (6) reported that cell damage caused by coal mine dust increases with the mineral and quartz content of the dust and with the geo· logical age and rank of the coals. Two studies, investigating the in vitro effects of mineral dusts. reported by Seemayer and Manojlovic (7) also obtained positive correlation between cytotoxicity and the mineral content of coal mine dust. Gormly (8) postulated that destruction of macrophages by certain mineral dusts is the first step in the development of pneumoconiosis. In 1980, Adamis and Timar (9) reported that quartz. sandstone, slate. respirable colliery dust. bentonite, illite, and some kaolins had cytotoxic effects on rat peritoneal macrophages""in vitro."" Walton,(10) however, reported that the presence of high clay, illite, and kaolin mineral exposures reversed the hazards associated with increasing quartz exposures. This finding was supported by Le Bouffant and coworkers.(11) They reported that illite present in coal mine dust strongly inhibited the pathogenic effects of quartz while kaolin had a weaker inhibitory effect."

Mar 1, 1989

By John W. Cole

The Butte district has been the principal producer of metallurgical-grade manganese in the United States since World War I. Manganese dioxide nodules are produced from rhodochrosite ore by concentrating the rhodochrosite and roasting the concentrate in rotary "cement-type" kilns. The Anaconda Copper Mining Co. is the only producer at present. Under the stimulus of a purchasing program administered by Metals Reserve Company during World War II, however, several independently owned or operated mines (including the Norwich) produced manganese carbonate ore. These mines were examined in Juno 1949 by John W. Taber, mining engineer, Bureau of Mines. A core-drilling program to develop ore in the Norwich mine was recommended and approved. drilling was completed early in 1950. This report gives factual data obtained.

Jan 1, 1951

By E. J. Lintner

This paper is one of a series being prepared by the United States Bureau of Mines describing clay mining and crushing methods and costs at various operations throughout the United States. These papers are designed to disseminate technical information regarding methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs might, in many instances, cause embarrassment to the individual operator as well as to the industry as a whole. On the other hand, operating costs are essential to a technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations may ensue. The author wishes to acknowledge the assistance of the following persons: L. W. Camp, general manager; S. Cooper, plant superintendent; and W. R. Riel, office manager.

Jan 1, 1936

By M. Clair Smith

This report is one of a series describing exploration, development, mining methods, and costs at United States open-pit mines; the Bureau of Mines prepares and publishes them in cooperation with the mining companies. Their purpose is to promote development and conservation of our mineral resources by disseminating technologic information on mining methods and practices at various United States mines. The exploration, development, equipment, and mining of a large, oxidized-copper ore deposit by open-pit methods, the leaching of the ore with sulfuric acid solution, and the recovery of the copper as cement copper are described herein.

Jan 1, 1958

By Aleksandar D. Bugarski

Three types of uncatalyzed diesel particulate filter (DPF) systems, three types of high-temperature disposable filter elements (DFEs), and one diesel oxidation catalytic converter (DOC) were evaluated in underground mine conditions for their effects on the concentrations and size distributions of diesel aerosols. Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. The DPF systems reduced total mass of aerosols in the mine air approximately 10-fold for light-load and 20-fold or more for high-load test conditions. The DFEs offered similar reductions in aerosol mass concentrations. The efficiency of the new DFEs significantly increased with accumulation of operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on performance of the filter element. The effectiveness of DPFs and DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for both DPFs and DFEs when the engine was operated at high-load modes than at low-load modes. The effects of the DOC on mass and number concentrations of aerosols in mine air were relatively minor when compared to those of the DPF and DFE systems.

Jan 1, 2009

By Wilbur I. Duvall

This paper presents arguments which show that a velocity seismograph should be used to measure building and ground vibrations produced by blasting . However , portable velocity seismographs suitable for this type of measurement are not commercially available . The paper describes how a velocity seismograph can be assembled from commercially available velocity gages , amplifiers , and recorders . Also , specifications are given which could be used in the design and manufacture of a portable velocity seismograph suitable for measuring vibrations from blasting .

Jan 1, 1964

By W. A. Selvig

"The tests described in this paper were conducted under the sponsorship of Subcommittee VII on Pulverizing Characteristics of Coal, a subcommittee of Committee D-5 on Coal and Coke, American Society for Testing Materials, with a view to evaluating various laboratory procedures for testing grindability of coal in connection with commercial pulverization of coal for use as powdered fuel. The subcommittee, at a meeting in New York City on February 21, 1934, selected for test four methods that had been developed during the past few years for testing grindabilitay of coal and were being used by coal-testing laboratories in the United States and Canada. These methods are:Bureau of Mines method, Cross method, Fuel Research Laboratory method, and Hardgrove method. Subcommittee VII agreed that the grindability tests should be made on five coals selected to cover a wide range of hardness. The Pittsburgh Experiment Station, Bureau of Mines, was asked to direct the investigation and to prepare representative samples of the coals. Laboratories of the fol. lowing institutions and companies agreed to cooperate by making grindability tests: Babcock & Wilcox Co., Foster Wheeler Corporation, Fuel Engineering Co., of New York, Fuel Research Laboratory of the Canada Department of Mines, and Northwest Experiment Station of the Bureau of Mines.ACKNOWLEDGMENTSHelpful suggestions in planning the investigation were made by A. C. Fieldner, chairman, Committee D-5 on Coal and Coke, A.S.T.M., and chief engineer, Experiment Stations Division, U. S. Bureau of Mines, Washington, D. C., and E. B. Ricketts, research engineer, New York Edison Co., New. York City.The coal samples were supplied through the courtesy of floats, Wheeler Corporation, New York City; Philadelphia & Reading Coal & Iron Co., Pottsville, Pa.; Pittsburgh Coal Co., Pittsburgh, Pa.; and Pocahontas Fuel Co., Inc., New York City."

Feb 1, 1936

By C. J. Cohen, L. A. Dahners

"SUMMARYA method has been developed for surveying, drill holes without lowering into the hole any surveying equipment other than an etch tube. The orientation of the rods at the collar of the hole is maintained as the etch tube is lowered. The attitude of the etch ellipse in depth with respect to the rod orientation at the collar can then be observed. This relationship permits the bearing of the hole in depth to he calculated. The rod orientation is maintained during the lowering by means of a pair of alinement clamps. One clamp is fastened to the top of each rod as the rod is coupled and is removed when the alinement has been transferred to the other clamp at the top of the next succeeding rod. A particular advantage of this survey technique is that surveys can be readily made in magnetic country rock.PRINCIPLE OF THE TECHNIQUEAn axial lamina of the column of drill roes is the lamina in which one fiber would be the centerline of the rods. In the new survey technique, the rods are fed into the hole in such a manner that the axial lamina of each successive rod maintains its position at the collar of the hole. In depth, as the rods bend in following the drill hole, the axial laminae also bend. The lamina that was originally vertical will, in general, be tilted away from the vertical. The trace of this lamina is marked on the glass etch tube before the tube is lowered in the hole. The axial lamina that becomes vertical at the survey station is recognized as that axial lamina which contains the long axis of the etch ellipse. The angle between the lamina originally vertical and the lamina vertical at the survey station is thus measurable. When the vertical axial lamina at one survey station has been determined by the etch ellipse at that station, angle R between this lamina and the vertical axial lamina at the next survey station becomes measurable also. By moans of angle R, and dip angles D1 and D2 at the two stations, the change in bearing (z) of the drill hole between the two stations can be calculated."

Aug 1, 1944

By Frank L. Hess

Vanadium, although widely spread in minute quantities through the crust of the earth, is found in few places sufficiently concentrated to be economically mined and prepared for use. Most rocks carry from a trace to a few hundredths of a per cent of vanadium oxide, and coal ash may carry about as much as the rocks, Much of the "coal" quoted in the literature as carrying vanadium has been asphaltite, and in other ccal the vanadium is of late introduction. The ash of the petroleums, though usually present in very small quantity, may carry a large percentage of vanadiun, so that production of vanadium from it has been seriously considered. Naturally the ashes of soze asphaltites similarly carry vanadium.' The great deposit at Minasragra, Peru, to which further reference will be made, is probably an altered asphaltite. Ilmenite and cther iron minerals usually carry vanadium 10 and some has been saved from the minette ores of France. 11 Many veins that carry lead copper and zinc minerals also carry a little vanadium, which, especially if the veins are in a comparatively dry region, such as the southwestern United States, northern Mexico, Northern Rhodesia, Southwest Africa, or Spain, collects in the oxidized parts of the veins as vanadinite,

Apr 1, 1932

By Vernon C. Allison

The explosibility of coal dust has long been recognized by competent investigators as constituting one of the dangers of mining coal and in the use of pulverized coal as a fuel in industrial plants. The Bureau of Mines has carried on extensive series of experiments dealing with this subject, and has not only developed methods for the practical prevention of this danger, but in the, course of these experiments has developed a standard method of determining the relative explosibility of coal dusts and other organic dusts.3 Oil shale contains compounds 'of carbon and hydrogen that are either of a petroleum nature and are strongly ,adsorbed upon the incombustible part of the shale, or else are present in the shale as a compound ("kerogen") which has the property of changing into petroleum-like products when acted upon by heat. The oil shales may contain varying amounts of the organic matter, ranging from a trace to more than 66 per cent, depending upon their richness; therefore, it is important to know whether the dusts formed in mining and handling these oil shales are explosive when mixed with air and if so, to indicate remedial measures. This paper gives the results of explosibility tests of several pulverized oil shale's, selected as being typical of those which in the future may be used in commercial shale-oil production test on a sample of typical Colorado oil shale has been., published in an earlier paper.4

Jan 1, 1926