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By Albert Mendelsohn

This paper, describing the mining practice at the Champion mine of the Copper Range Copper Mining Co., is one of a series of papers on mining methods and costs being prepared by the United States Bureau of Mines. Mining practice at the Champion mine has undergone considerable change during the last four years. Previous to that time the mine was worked by the horizontal out-and-fill method, the stopes starting near the shafts and advancing away from them (fig. 2). The floor pillars were mined by the inclined cut-and-fill method, working en the retreat or toward the shafts (fig. 1). At present the mine is being developed to .tope entirely on the retreat by a sublevel inclined cut-and-fill method.

Jan 1, 1931

By D. Harrington

The prevention of accidents to children from blasting cans is of vital importance not only to everyone using commercial explosives but to the country at large. The manufacturers of explosives have realized this danger for years and have attempted to publicize the hazards of allowing blasting caps to fall into the hands of children. Unfortunately, many of tie users of explosives have failed to realize the danger or have ignored their responsibilities in the matter. Investigations of accidents to children from blasting caps (and scores of them occur annually) reveal that most of them are caused by blasting caps picked up or made easily accessible to the victims. The children who are blinded, maimed for life, or killed are in large part the innocent victims of the carelessness, thoughtlessness, or negligence of their elders, by whom blasting caps are left lying about, carried in the pockets, dropped or lost around blasting operations, stored away and forgotten, or left in places where trey can be found or are accessible to children. Many such accidents occur to children under 12 years of age, when they are still curious or inquisitive. One of the first reactions of a child upon finding a blasting cap is to investigate and "see" how it is made or how it "works." A blasting cap in itself, with one end open, invites a child to poke it with a nail, piece of wire, or some other object to see what is inside; or he may attempt to break it open with a rock or hammer. A lighted match could be thrust into the open end, and there are numerous other approaches, may of which can result in serious accidents.

Jan 1, 1944

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1962, to June 30, 1963, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1963; in general, the research reported in these publications antedates the report period.

Jan 1, 1965

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1962, to June 30, 1963, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1963; in general, the research reported in these publications antedates the report period.

Jan 1, 1965

From 1886, the first year shipments were recorded, until 1939, the Leadville district produced over 3,500,000 long tons of manganiferous ore. Of this total, metallurgical-type ores comprised 27 percent and manganiferous iron ores suitable for fluxing in lead smelters made up 73 percent. In 1939, the Bureau of Mines, as part of the strategic minerals investigative program being conducted at the time, requested the Mineral Industries Survey Section of the Mining Division to make a comprehensive study of the manganese resources of the Leadville area. This investigation, owing to the caved and flooded condition of the underground mine workings, was necessarily confined to a study of old maps, production records, and geological reports, and the results were published as an Information Circular in July 1940.

Jan 1, 1949

By Harvey Patashnick

Current state-of-the-art microweighing technology represented by the Tapered Element Oscillating Microbalance (TEOM) is utilized as the basis for a new generation of Personal Dust Exposure Monitors (PDEM's). Two design configurations are presented. The first is an end-of-shift analysis system which uses small TEOM-PDEM cannisters that replace the filter cartridges in the current PDEM system. All other components carried by the miner (cyclone preseparator and pump) are the same. After the shift the TEOM cannister is plugged into an interface box which enables a minicomputer to automatically identify the unit, determine the dust mass increase during the shift, compute the shift average dust mass concentration, and print out and/or store the data. The second design is a real-time TEOM-PDEM system which is capable of operation over a 10-hour shift and on demand display real-time dust concentration level, time weighted average, and shift average concentration. As a result of the design study, a prototype end-of-shift analysis system was fabricated and delivered to the Bureau of Mines. A description of this system which consists of six TEOM cannisters, interface electronics and minicomputer is given. The system represents a significant advance in the dust monitoring program in terms or accuracy and automation.

Jan 1, 1983

By H. W. Kilau

The Bureau of Mines evaluated synthetic fluorspar as a substitute for natural fluorspar flux in basic cupola ironmaking. The synthetic fluor-spars tested were prepared from waste fluosilicic acid generated during the processing of fluorapatite ore. The cupola trials showed the synthetic products to be the equivalent of natural fluorspar from an operational standpoint. However, wet scrubber sampling showed that substantial losses of volatilized fluorine occurred from the cupola during operation. The losses during synthetic fluorspar trials considerably exceeded those from natural fluorspar trials. Laboratory viscosity testing, using a high-temperature rotational viscometer, confirmed this finding and indicated that fluorspar volatility in slags is related to slag basicity. Synthetic fluorspar is accordingly recommended more for highly basic cupola operation (>1.3 basicity) than for neutral or acid operation, because of the increased potential for pollution and baghouse filter detezioration"

Jan 1, 1989

By C. C. Popoff

The Dunkleberg district is in the Flint Creek Range of the northern Rocky Mountains, about 45 miles northwest of Butte, Mont. Silver - lead and zinc mineralization occurs over an area 4 miles long from north to south and 1 to 2 miles wide from west to east. Ore in appreciable quantity has been produced, mostly from the Forest Rose group of mines in the southern part of the district. The Forest Rose mine was the largest producer of lead and the Wasa mine, a mile farther south, the main producer of zinc. The total output of ore from these properties during World War II was 113,000 tons, or 98.2 percent of the total recorded production of the district. The Wasa mine was examined by a Bureau of Mines engineer2/ in 1944. Subsequent investigations during 1946, 1947, and 1948 included trenching and drilling Fn the Wasa area and examination of the Forest Rose and other mines.

Jan 1, 1953

By R. Karl Zipf, Z. T. Bieniawski

"Researchers at The Pennsylvania State University are engaged in a project to understand the mechanics of respirable size fragment formation in coal. The project is based on the premise that a thorough understanding of the fundamental mechanics of fine fragment formation may lead to techniques for reduction and better control of coal dust problems in mines. Presently, it is believed that the mode of fracture propagation which can range from pure tensile to pure shear or any mixed mode in between and the loading or displacement rate can influence the amount of respirable size fragments that are generated on new fracture surfaces during the fracture propagation process The essence of any coal cutting process is one of mixed mode fracture propagation. To study the crack propagation process, a unique mixed mode testing rig was designed and fabricated. This rig is capable of applying loads to a prenotched test specimen that range from pure Mode I (tensile mode) to nearly pure Mode II (shear mode) or many mixed mode loading combinations. It is also possible to apply different loading or displacement rates to the test specimen. With this rig, it is possible to create new fracture surfaces via the different fracture modes and under various loading conditions.These new fracture surfaces are examined with a scanning electron microscope (SEM) to characterize the amount of structural damage and respirable size fragment formation that occurs during the fracture process. Initial observations suggest that the amount of fine fragment formation and the new fracture surface appearance is related to the fracture initiation conditions, particularly the fracture mode and the loading rate. Mode II loading and higher loading rates seem to generate more structural damage and respirable size fragment formation that Mode 1 loading at slower rates.With the mixed mode test rig, the mechanics of fracture initiation for a single crack can be controlled to better understand its influence on respirable size fragment formation. Such understanding may lead to methods which characterize the tendency of specific coal seams to produce undesirable fine fragments during the fracture process, or it may lead to rational recommendations and design guidelines or coal mining machines which inherently produce less dust.IntroductionAs part of a larger effort to reduce the incidence of coal workers pneumoconiosis (black lung) in coal miners, researchers at The Pennsylvania State University are engaged in a project to understand the fundamental mechanics of fine fragment formation in coal. This project is part of a com¬prehensive research effort within the Generic Mineral Technology Center for Respirable Dust which is jointly administered by The Pennsylvania State University and West Virginia University.The principal source of the coal dust in underground mining is the cutting operation. The U.S. Bureau of Mines (USBM) and various European research organizations have conducted investigations into the mechanics of coal cutting for many years. These studies of airborne respirable dust (ARD) formation have concentrated on empirical studies of the various cutting parameters and their effect on ARD for¬mation. The parameters study include depth of cut, cutting speed and bit spacing.(1,2) Other studies investigated the effect of symmetric and asymmetric bit wear and various bit geometries and designs (3-5) Roepke(6) summarized the principals of proper coal cutting to minimize dust formation by recommending to ""cut at maximum depth (maximum advance rate) at all times, at minimum RPM, with the fewest possible bits, having the lowest possible included tip angle."" Most coal in the U.S. is mined with the continuous mining machine which inherently cannot meet these design recommendations.(3)It is recognized that respirable size dust particles are formed and/or liberated by a fracture process. One extremely interesting and useful study performed very early in the USBM dust re"

Mar 1, 1989

By Aldo L. Furno

Sufficient quantities of combustible vapors are released by some sulfurs to produce flammable atmospheres under prolonged storage. Hydrogen sulfide and carbon disulfide appear to be the principal flammable constituents in the vapor space above molten sulfur. If sufficient carbon disulfide is present, ignition of the vapor-air mixtures can occur spontaneously on contact with the heated surfaces found within storage tanks.

Jan 1, 1963

By George T. Faust

The petrographic microscope plays an important role in the mineral dressing of nonmetallic materials. Petrographers and mineral technologists have evinced an interest in the technique developed, specifically, for mineral-dressing problems. The following dissertation makes the informa¬tion more generally available. ACKNOWLEDGMENTS The authors are indebted to O. C. Ralston, chief engineer, Nonmetals Division, and to Will H. Coghill, supervising engineer of the Southern Experiment Station for a critical reading of the manuscript. They are also indebted to their colleagues for technical information obtained in the course of cooperative work, in particular to J. B. Clemmer for the use of the data on fluorite.

Jan 1, 1940

By D. W. Butner

This report is concerned with the conditions affecting the methods and costs of mining phosphate rock in that part of the western phosphate field that is in Bear Lake and Caribou Counties in southeastern Idaho ( see fig . 1) . The area was selected because it contains most of the known phosphate reserve and because its geology has been studied more extensively than that of other sections . Deposits of phosphate rock on public land may be leased from the Government under the terms of the Mineral Leasing Act of 1920 , subject to the regulations of the Bureau of Land Management . Public interest in phosphate production is growing , as shown by an increasing number of applications for leases . Two mines are being operated steadily for the production of phosphate rock by companies that have also the necessary processing plants for the manufacture of fertilizer . Total western phosphate - rock production in 1947 is reported by the Economics Statistics and Division of the Federal Bureau of Mines to have been 1,193,000 long tons , mined in Idaho , Montana , and Wyoming . The average grade was 30.7 percent of contained phosphorus pentoxide (P205 ) ; the average value at the mines was $5.67 per long ton . Idaho contributed 905,000 tons , or somewhat more than 75 percent of western production . Western fertilizer plants took 23 percent of total production; 76 percent was exported . Strip mining accounted for 75 percent of the Idaho tonnage; the remainder was stoped from underground workings . Rock must contain a minimum of 30 percent P205 to be commercially useful for the production of superphosphate fertilizer by current acid treatment methods . Research by corporations and Government agencies has been directed toward the use of lower - grade ore . So far , only by smelting can rock containing as little as 25 percent P205 be used economically . Any development of processing or use pattern that would render the mining of , say , 20 percent rock profitable would have important effects in reducing the unit cost of mining . In the search for metallurgical improvements , consideration should be given to the saving of valuable components of the rock, such as vanadium and fluorine , both of which are present in the beds .

Oct 1, 1949

By ALICE V. Petar

Among the rarest of the rare metals are four that are linked together by a common historical background as well as by chemical relationship. With the excep- tion of indium, these metals are likewise characterized by the patriotic nature of the names given them by their discoverers. The existence of gallium, germanium, and scandium, was predicted by the Russian cherist, D. I. Mendeleeff some time prior to their discovery; and these elements might well have been overlooked, had not the search been stimulated by the urge to confirm the scientific hypothesis of their existence. Nowhare found in sufficient quantities to attract attention, these little known elemente are nevertheless widely distributed in the earth's crust. So far they are found commercially mostly in the sulphide ores of zinc and must be considered as being largely curiosities of the zinc smelter. Recent progress in electrolytic zinc refining, however, now gives promise that the way may be open for the recovery of these very rare metals in larger quantities-- possibly in quantities sufficient to permit of their finding commercial utilization.

Nov 1, 1930

By C. J. Chindgren

Upgrading of commercial red cake and recovery of vanadium oxide from uranium-vanadium mill solutions were investigated by the Bureau of Mines. Alternative procedures potentially useful for manufacture of high-quality vanadium oxide at the mill site were explored and developed. The simplest and best procedure for converting commercial red cake containing about 10 percent combined sodium and potassium oxides (Na20) (K20) into a 98- to 99-percent vanadium pentoxide (V205 product appeared to be a metathesis in an ammoniacal solution of ammonium sulfate. Molybdenum, as well as the alkali metal oxides, was removed from the red cake by this procedure at a modest expenditure of labor and reagents. When preparing vanadium oxide of higher grade, it was necessary to dissolve the red cake and reprecipitate the vanadium as ammonium metavanadate. Calcination at 450° C, decomposed the metavanadate and yielded oxide of about 99.5 percent V205. By recyrstallizing the metavanadate before decomposition, an oxide product approaching 99.9-percent purity was obtained.

Jan 1, 1962

By J. R. Hauger, P. A. Romans, W. J. Niebuhr

With suitable instrumentation and techniques it is possible to determine the presence of tantalum in columbium to 20 ppm . This paper discusses the selection of X- ray spectrographic instrumentation and describes a technique for accomplishing the low level determination of tantalum . An ion- exchange method of separating tantalum from columbium is also described .

Jan 1, 1964

By R. S. Dean

In addition to the normal work and that pertaining to strategic minerals, the Metallurgical Division has been made responsible for carrying on major investigations in the development of processes' for the treatment of low-grade domestic manganese ores that heretofore have failed to yield products suitable for the preparation of ferromanganese, an alloy essential to every ton of steel produced. These investigations are particularly important at this time because of their part in tucking this country self-sufficient with regard to manganese when the stock-piled ore becomes e exhausted and as foreign shipments of ferro-grade ore are cut off. The results indicate that there is a good probability of accomplishing this objective, while at the same time conservation may be promoted through the use of normally useless material from the large, low-grade ore deposits.

Jan 1, 1941

By A. R. Taylor Jr.

The heat capacities of a-quartz form beryllium fluoride were measured at approximately 3° intervals from 8° to 300° K., using an adiabatic calorimeter. At 298.15° K the heat capacity and entropy were 12.39 cal/deg mole and 12.75 ±0.04 eu respectively. Enthalpy measurements were made with an ice calorimeter at approximately 30° intervals on the quartz and glassy forms of beryllium fluoride between 300° and 1,200° K. A melting point of 825° K and an 0,-8 type transition at 500° K with a heat effect of 75 ca1/mole were deter-mined from the enthalpy data for the quartz-type sample. Beryllium fluoride glass crystallized spontaneously into the quartz modification at 500° K. The heat of the reaction BeF2 (a-quartz) .... BeF2 (glass) was found to be 1,125 ±16 cal/mole at 298° K by solution calorimetry. This value, when corrected to 273° K, was used to correct for the heat absorbed by the formation of glassy BeF2 when the sample was dropped into the ice calorimeter from temperatures above the melting point. Using corrected enthalpy measurements, the heat of fusion was determined to be 1.13 kcal/mole at 825° K.

Jan 1, 1965

By L. C. Brichta

The Canyon Diggings zinc-lead deposit is in an area of structural deformation of sedimentary rooks in Newton County, Mo., 14 miles southeast of Joplin, within the southern limits of the Tri-State district. Mining and milling on the several tracts covering the area had been carried on sporadically since 1900, and incomplete records show a production of 1,341 tonsof zinc and lead concentrates. On the northern part of the deposit the predominant metal is which occurs as galena, cerrusite, and pyromorphite in broken chert near the surface. On the southern part, lead is subordinate to zinc, which occurs mainly as carbonate and silicate minerals in brecciated chert to a maximum depth of about 150 feet. Analyses of samples from Bureau of Mines drilling indicate that approximately 77 percent of the zinc and 50 percent of trio lead i8 in nonsulfide minerals resulting from the oxidation of sphalerite and galena. Between August 12, 1948, and October 5, 1949, the Bureau of Mines investigated the deposit by churn drilling and sampling 85 holes aggregating 10,571 feet of bore and sampling two mill-tailings dumps and three mine dumps. Factual data on the investigation and the logs of Bureau of Mines drill holes are presented in this report.

Jan 1, 1950

By A. W. Fahrenwald, W. W. Staley

"In flotation concentration, various machines are employed for agitation and aeration of the ore pulp in the operation of frothing. The power required in the operation of these machines varies considerably with the type and make of machine used. The object of this investigation was to determine the effect of certain physical properties of the pulp particularly viscosity, density, and temperature - upon the power required by certain forms of pulp agitators.The viscosity factor is most involved because it is affected by temperature and by density. Viscosity of liquids and suspensions has been extensively studied and the physics and mathematics of the subject are much enlarged upon in books and in the literature. It is not, however, the intention of this study to become involved in the intricacies of these phases of the subject.The agitation of the various mediums in the experimental work did not last long enough to cause a measurable rise in temperature from the ""beating"" of the medium, hence no cognizance is taken of this factor.No attempt has been made to correlate the data obtained with the impeller with any information regarding centrifugal pumps. The object sought here is quite foreign to the problems of pumping. The impellers used are ""open"" and air is involved.The experiments performed and the data obtained are presented. Only that amount of discussion necessary to make the results understandable is given.Tap water was used in all experiments. A comparison of distilled water and tap water showed no measurable difference. In the experiment in which sodium chloride was needed, the commercial salt as used in fire assaying was taken. The quartz was of the ""bull quartz"" variety, thoroughly washed free of iron oxide."

Jun 1, 1930

By Robert W. Geehan

The Bureau of Mines has been developing deposits of critical and essential minerals in the United States since 1939. A preliminary examination of the Union lead mine was made in November 1944 and January 1945 by W. T. Benson, a Bureau of Mines engineer, who recommended development by diamond drilling. The Bureau conducted a drilling project at the mine from February 12 to May 16, 1947. The property is in sec.12, T. 17'N., R. 19 E., Mount Diablo Base and Meridian, in. southern Washoe County, Nev., about 15 miles south of Reno. The Union lead mane, also known 4s the Commonwealth mine, has been an intermittent producer of zinc-lead-silver ore since 1860. During World War II, ore was shipped to smelter& near: salt Lake City, Utah. The Bureau drilled 21 diamond-drill holes having a total length of 1,549 feet and 20 long percussion-drill holes with a total length of 359 feet. The program was designed to test for horizontal and vertical extensions of the ore body and to prospect for parallel ore bodies. As a result of this program, extensions of the ore zone were established, but no parallel ore-bearing structures were found. The areas drilled were limited by drill sites available.

Jan 1, 1950