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By T. H. Miller

This piper is a continuation of a series of yearly review articles started in 1925 by Thomas Varley. The development of flotation has been rapid, and better understanding of the functions o' flotation reagents has resulted in many changes in the kinds and quantities o reagents used. It is the purpose of this report to present the information in such a manner as to be of value to the milling industry as well as to the manufacturer of flotation reagents. These data have been compiled from a. survey of approximately 250 flotation plants of all classes within the United States. Many of these plants made complete reports of their operations, out others were apparently unable to supply this information in sufficient detail to meet the requirements of this investigation. Although it is realized that the data obtained in this survey are not as full as they should be to render the greatest service possible to the milling industry, it is hoped that succeeding articles will include complete information regarding milling; conditions and recoveries. As in the past, every effort has been made to conceal individual plant operations. RESULTS OF INVESTIGATION Table 1 gives the tons of ore treated by gravity and flotation methods and the concentrates produced as reported by 208 plants. The totals of 77,043,535 tons of ore and 4, 596,640 tons of concentrates from this table compare with totals of 78,973,012 tons and 4,683,972 tons respectively (furnished by the Bureau of Mines, Division of Mineral Statistics), indicating that the milling survey is about 98 per cant complete.

Jan 1, 1930

By Paul G. Swanson

This manual of practice is to be used in combination with the final reports for the study of spoil stability in the Eastern Coal Province. The manual applies the predictive matrices developed in the parent study for use in evaluating the stability of typical mine spoil slopes. The values of internal friction and pore pressure coefficient are derived for many varied slope conditions. The results can be used in conventional stability analysis equations to assist the mine operator or regulatory personnel in evaluating spoil stability from very limited information.

Jan 1, 1983

By H. G. Iverson

The effects of adding boron and boron plus carbon to electrorefined vanadium were evaluated with respect to mechanical properties at low temperatures and response to heat treatment. Grain size was significantly decreased with the addition of 0.05 percent boron, the decreases ranging from 30 percent at 800° C to 75 percent at 1,100° C. Increasing the boron content resulted in only a small increase in strength at room temperature, but at 77° K, boron contents of 0.005 to 0.076 percent increased the yield strength of vanadium over 50 percent, from 70,000 psi to 110,000 psi. When boron and carbon were present together, the individual grain-refining effects obtained with either element were retained. Approximately a twofold increase in strength was obtained by age-hardening the alloys containing both boron and carbon. Alloys with only boron additions did not age-harden.

Jan 1, 1968

By J. R. Thoenen

During 1928 questionnaires covering the calendar year 1927 were sent to over 1700 quarries: producing stone for purposes other thaw cutting to dimension. These inclined producers of stone for limn burning; cement manufacture, rip rag, and crushed stone. The various rinds of stone represented were limestone, trap rock, sandstone, granite, and marble. Replies received from limestone producers prior to November, 1928, were compiled into tables and published in February, 1925, as a preliminary report (Bureau of Mines Report of Investigation 2911).

Jan 1, 1930

By J. B. Zink, M. J. Peterson

A semiquantitative spectrochemical method was developed and applied to the analysis of ash of U.S. coals . A low- temperature ashing procedure was used to minimize the loss of volatile elements . The analytical procedure provides for the estimation of 68 elements including major , minor , and trace constituents . Standards for the trace elements were prepared in a synthetic base mixture that approximates the average composition of U.S. coal ashes . Excitation was achieved with a d- c arc , spectra were recorded photographically , and interpretation was made by visual comparison of spectra of unknowns with spectra of graded standards series . Thirty- six trace elements were found in the analysis of 900 samples . Details of the procedure are presented , including sample and standards preparation , excitation and exposure conditions , spectral lines used , and approximate limits of detectability .

Jan 1, 1964

By J. L. Reuss

The Bureau of Mines investigated the technical feasibility of smelting copper concentrates containing chalcocite (Cu2S) and native copper using nonpyritic sulfur-bearing materials to aid matte formation. The procedure consisted of combining various proportions of commercial chalcocite concentrate, smelter slag, fluxes, and matte-forming constituents to produce charges of comparable compositions. The mixtures were charged in fire-clay crucibles and smelted in an induction furnace at 1,300° C. The research proved that either sulfur or gypsum can replace pyrite as a matte-forming material, and that gypsum produces an exceptionally high-grade copper matte. The addition of small quantities of metallic iron to the nonpyritic smelting charge furthers the removal of sulfur, improves the recovery of copper, and makes it possible to utilize gypsum as the exclusive flux and matte-forming ingredient, thereby eliminating the necessity of adding limestone.

Jan 1, 1968

By F. S. LOTT, I. S. CULVER

The number of petroleum refineries in the United States decreased during 1948 from 390 to 375, continuing the trend to fewer units of larger individual capacity that has persisted since the peak in number of plants was recorded on January 1 , 1936. Large - scale construction of new processing facilities continued through 1948 with a resultant gain in daily crude-oil throughput capacity of installed equipment from 6,034,252 barrels on January 1 , 1948 to 6,438,995 barrels on January 1 , 1949. The capacity of the average refinery to process crude oil therefore increased during 1948 from 15,472 barrels daily to 17,171 . The principal areas of expansion of facilities were the strategic seaboard districts of the Texas and Louisiana Gulf Coast and the East Coast , and the important Indiana , Illinois , Kentucky, etc. , district that supplies markets in the upper Middle West region . These four districts accounted for 79 percent of the total new capacity added in the United States in 1948. The relatively small petroleum- refining industry of the Other Rocky Mountain district experienced a vigorous expansion in 1948 that will continue during 1949 . Capacity building on January 1, 1949 , amounting to 341,500 barrels daily, was 25,750 barrels lower than the comparable total on January 1 , 1948, but was the second highest on record . New construction was heavily concentrated in the Texas Gulf, East Coast , and Indiana -Illinois

Sep 1, 1949

By J. G. Kirby, F. S. LOTT

The mmber of petroleum refineries in the United States decreased during 1949 from 375 to 367 while the total crude-oil charging capacity of refineries continued to increase. A gain in the through-put capacity of 257,305 barrels daily raised the total to a new high level 6,696,300 as of January 1, 1950. The capacity of the average refinery to process crude-oil increased during 1949 from 17,171 barrels daily to 18,246. The four coastal refinery districts accounted for 178,900 barrels or 70 percent of the total capacity increase and the Illinois-Indiana- Kentucky district 57,950 barrels, or 23 percent. Slight declines in capacity were reported in the Texas Inland and the Arkansas-Louisiana Inland districts. The capacity building on January 1, 1950, 145,600 barrels daily, was less than half the amount under construction a year earlier. Most of the new construction involved enlargement of existing refineries and was confined to the East Coast and Indiana-Illinois-Kentucky districts. Two new refineries, however, were under construction, one in Oklahoma and the other in Texas. The shut-down capacity increased for the first time since 1946, and the 473,302 barrels daily reported on January 1, 1950, was the largest recorded since January 1, 1938. The only refining district showing a decline in the shut-down capacity was the Appalachian No. 2 district. The largest increases were reported in the Texas Gulf, Indiana-Illinois- Kentucky, California, and East Coast districts. The operating ratio of the petroleum refining industry, as indicated by dividing the January 1950 runs to stills of 5,483,000 barrels daily by the total installed capacity January 1, 1950, was 81.9 percent, compared with a ratio of 87.8 percent at the beginning of 1949.

Aug 1, 1950

By Eric R. Bauer

This Bureau of Mines publication describes and illustrates the physical signs of excessive loading on mine roof supports, installations, and openings. It is designed to assist mine personnel in recognizing potentially hazardous ground conditions, by emphasizing the preliminary effects of developing unstable ground. Increased worker awareness can be expected to reduce the injuries and fatalities resulting from falls of roof, rib, and face.

Jan 1, 1985

By S. M. Shelton

The widespread occurrence of domestic manganese deposits and the shortage of ferromanganese-grade ore have been sources of much speculation and investigative effort for many years. The present emergency has intensified the search by the Bureau of Mines for methods of producing ferromanganese-grade concentrates4/ from low-grade ores.

Jan 1, 1941

By S. M. Shelton

[The widespread occurrence of domestic manganese deposits and the shortage of ferromanganese-grade ore have been sources of much speculation and investigative effort for many years. The present emergency has intensified the search by the Bureau of Mines for methods of producing ferromanganese-grade concentrates4/ from low-grade ores.]

Jan 1, 1941

According to industry representatives, U.S. producers were listing unalloyed 95.5 percent aluminum ingot in October at 53-57.5 cents per pound, but reportedly much is being priced at 53 cents. New York dealers raised their October positions by about 3 cents to 56-56.5 cents, mainly to cover spot supply shortages. London Metal Exchange 3-month forward contracts traded up in October from 52.3 to 57.3 cents per pound and closed at 56.4 cents. ASBESTOS The Jaquays Asbestos Corp. has announced the imminent closure of its mine and mill in Globe, Arizona. This is the last asbestos producer in the State having operated continuously, except during the early thirties, since 1914. Cost of compliance with environmental regulations was given as the reason for closure.

Jan 1, 1978

By Frank J. Wiebelt

Work on the Abbott-quicksilver property was part of the general program of th~ Bureau of Mines in its investigation of domestic mineral resources, which are essential to national defense or industry and of which our present or probable future supplies are inadequate. The mine was discovered in 1862, and the intermittent production up to 1947 has totaled around 37,500 flasks of quicksilver. Output has come from ore shoots formed in the vicinity of fault intersections in a narrow zone composed of lenses of silicified serpentine breccia interbedded with shale. Work by the Bureau included the drilling of six diamond-drill holes aggregating 2,845 feet. Several possible ore zones were intersected by the drill holes. Field work was begun in April 1948 and concluded in October of the same year. This report gives detailed results of the diamond drilling and a brief account of the history and description of the ore deposits.

Jan 1, 1949

By Allen D. Look

Underground fires often prove difficult to control , and a small fire can quickly grow into a large one , endangering life and causing large property damage . Even a small underground fire may produce enough noxious gases to cause suffocation ; therefore , every precaution should be taken to prevent and control such fires . It is ironic that mine fires should be caused when utilizing materials that are in themselves fire - resistant ; yet , cutting and welding of iron and steel are proving to be common causes of underground fires in metal mines . This paper includes 19 examples of underground fires of this nature , and undoubtedly this is only a fraction of the number of similar fires that have occurred in the last few years . This paper will review some metal - mine fires caused by cutting or welding and point out precautions to be taken to prevent other fires from this cause .

Apr 1, 1948

By B. C. Parks

This is the first of a series of reports on the relation between microscopic composition and chemical and physical properties of banded bituminous coals. It describes the relation between microscopic composition and behavior during thermal decomposition of a heterogeneous, high-volatile A bituminous coal from the Chilton bed in West Virginia. The standard free-swelling test was used as a simple means of studying the effect of heat on the coal. Although swelling indexes are not precise indicators of coal behavior in the coke oven and have limited value in caking investigations, they are reliable for predicting expansion of coal in a fuel bed and have practical value in the study of fuels. The swelling test also supplements other useful laboratory tests for determining the plastic and expansion properties of coal.

Jan 1, 1957

By Herbert R. Babitzke

The purpose of this investigation was to optimize the high-temperature properties of columbium and tantalum. Columbium and tantalum were combined with selected alloying elements to achieve solid solution and dispersion strengthening. Fifty-six alloys were evaluated to determine their formability, hardness, strength at elevated temperatures, and oxidation resistance. The following six alloys showed high-temperature strength: [Cb-15Hf-5W-2Zr-4Al-4Ti-2N Cb-15Hf -5W-5Zr Cb-15.3Ti-4.1Zr-13.7Hf Ta-20Hf-4Al Ta-30Hf-4Al Ta-20Hf-5W-4Al] At 1,200° C, the columbium alloys had strength values of 40,000 psi or greater, and the tantalum alloys had strength values from 50,000 to 58,000 psi. For a 2-hour test period at 1,000° C, weight gains of only 9 and 8 mg/cm2, respectively, were observed on oxidation testing of two alloys, Cb-15Hf-5W-2Zr-4Al-4Ti-2N and Ta-20Hf-5W-4Al.

Jan 1, 1968

By E. D. Gardner

The Bureau of nines, in cooperation with the mining companies of the Southwest, is conducting an investigating to ascertain the safest and most economical explosives to use in metal mines, and to ascertain the best methods of blasting under various conditions. A part of this investigation has been a study of drilling and blasting drift rounds in metal mines. This paper covers one phase of work on drift rounds and discusses the methods of loading the individual holes of the rounds. The blasting tests, on which this paper is based, were made at the Copper queen Branch of the Phelps Dodge Corporation at Bisbee, Arizona.

Jan 1, 1927

By R. V. Ramani, R. Bhaskar

"While the National Academy of Sciences has stated that gravimetric sampling technology for compliance purposes is adequate, research into various aspects of respirable dust control require data on many other parameters of airborne dust. These, in turn, have created the need to use many instruments, other than personal gravimetric samplers, in mi ne environments for dust measurement. There is a need to evaluate the performance of these instruments under conditions of potential use.As part of research in the Generic Technology Center for Respirable Dust, cascade impactors, gravimetric personal samplers and gravimetric samplers collecting dust using isokinetic sampling principles were employed for dust measurements under identical conditions in a mine airway. During the course of the experiments, 8-stage cascade impactors and gravimetric samplers drawing air isokinetically were located in the center of a mine airway at various stations. Two types of data were examined - concentration of dust and size distribution of the dust collected in the samplers. The data show that the amount of dust collected by an impactor is less than half the amount collected isokinetically. The size distributions of the dusts collected from the two instruments, though comparable, show a consistent difference in median diameters. The cause for this bias is examined.The paper presents and discusses the results of the tests, including the concentrations and size distributions obtained from the two instruments for different experimental conditions. There is a need to document the performance of various dust measuring devices in mine airflow conditions.INTRODUCTIONThe sampling of airborne dust in mines can be done for several purposes. Traditionally, dust sampling has been restricted to the gravimetric measurement of airborne respirable dust to comply with the regulations governing the mining industry. Instruments such as the MRE gravimetric sampler, and personal gravimetric samplers that have collection characteristics similar to the human respiratory system have been in use for the last two decades. Presently available instrumentation for the purpose of regulation have been considered adequate by the Committee on the Measurement and Control of Respirable Dust in Mines (National Academy of Sciences, 1980),"

Jan 1, 1989

By J. Douglas Causey

In 1986 and 1987, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied 73,010 acres of the 76,480-acre Lower Owyhee Canyon Wilderness Study Area (OR-003-110) in order to evaluate its identified mineral resources. The study area is in Malheur County, OR, about 8 miles north of Rome. There are approximately 7.7 million tons of subeconomic zeolite (heulandite and/or clinoptilolite) resources with ammonia ion exchange capacities as high as 1.75 milliequivalents per gram in the Chalk Basin-Lambert Rocks area. The bed is 25 ft thick with less than 100 feet of overburden. This resource probably will not be mined in the foreseeable future.

Jan 1, 1989

By J. L. Reuss

The Bureau of Mines derived information on the softening characteristics of both unfired and indurated iron ore pellets as measured by hot compression strength in a laboratory study. A surprisingly high hot strength (240 1b per ½ -inch spheroid) was developed by unfired magnetite pellets near 900° C; lesser maxima were developed by pellets made from hematite and specularite concentrates near 1,000° C. Those from goethite remained weak throughout the pre induration heating. Fully indurated commercial pellets retain a high resistance to softening when heated in air. On the contrary, in a hot reduing atmosphere their high cold crushing strength dissipates rapidly. At 1,000° C, for example, the average compression strength of seven different commercial pellets was 110 lb; at 1,100° C, the hot strength was only 60 lb. After a rather sharp initial drop, the loss of strength with increase of temperature was gradual. There was no sudden collapse, nor any significant difference, in behavior of commercial pellets whether made from magnetite or hematite concentrates.

Jan 1, 1968