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By H. Tomlinson

Fatalities from falls of roof and coal are responsible for the death of more than 1,000 miners annually in the bituminous coal mines of the United States, or practically one-half of the total fatalities in and about these mines. The men are killed by falls singly or in small groups and little or no publicity is given these accidents as they lack the spectacular features of gas and dust explosions. As a result, the public and even the miners have the impression that accidents from falls of roof and coal are just one of the unavoidable hazards of the coal-mining industry. This belief is not true. Accidents caused by falls can be avoided largely by the application of sound engineering principles, by education, and by proper leadership in the industry, just as gas and dust explosions and accidents caused by explosives have been reduced in recent years.

Jan 1, 1933

By Howard F. Puariea

This paper is one of a series describing methods and costs of recovering sand and gravel from alluvial deposits in the United States and deals directly with the methods employed by the Portland Gravel Co. in operating a clamshell dredge on the Willamette River near Portland, Oreg., and a pump dredge on the Columbia River near Vancouver, Wash. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent local expenditures only and not total production costs. It is recognized that publication of total costs may in some instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand operating costs are essential to the technical discussion and study of 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 shall ensue.

Jan 1, 1932

By M. Howard Berliner

During the spring of 1944, the Bureau of Mines investigated the Crescent mine area near the village of Rewey, Iowa County, Wis., as part of a general investigation of the zinc-producing area of southwestern Wisconsin. The work was done when every effort was being made to increase the production of metals important to the Nation's war program. The Bureau of Mines completed 24 churn-drill holes in an area immediately to the west of a mineralized section which had been mined through shallow workings for lead and zinc more than 40 years earlier.

Jan 1, 1948

By John Durkin

Owing to the daily exposures of uranium mining personnel to 222Rn daughters, a device is needed that will continually monitor individual exposure. Such a device has been built and tested by the Bureau of Mines and is known as a radon daughter dosimeter. This is an electronic instrument using a solid-state detector and circuitry. The concept of the instrument, which is a personal device worn throughout the working shift, is to evaluate an individual's cumulative exposure to airborne radon progeny, expressed in units of working level hours. Since the instrument is in close proximity to the miner and measures continual exposure, it avoids the errors caused by the present technique of spot checking of the environment and provides a more accurate account of total cumulative exposure.

Jan 1, 1977

By Webster S. Anderson

Two series of tests were run with planer model 'BB": one at the Arickaree mine of the San Francisco Chemical Co., Rich County, Utah, and one at the Roslyn No. 9 mine of the Northern Pacific Railway Co., Roslyn, Wash. The tests at the Arickaree mine were started on June 25, 1958, and continued until September 30, 1958. Prior to these tests, an electrically activated remote-control system was installed, and other modifications were made on the planer. The tests showed that the planer in general and the remote-control system worked very well; however, the various cutting tools used would not consistently penetrate and cut the phosphate rock. This indicated that the cutterhead design had to be changed before the planer would operate efficiently in phosphate beds similar to the "A" bed in the Arickaree mine.

Jan 1, 1962

By William C. Cooley

A review was made of two Russian books and a chapter from a third book dealing with pipeline transport of coal. Emphasis was placed on hydrotransport of coarse coal in underground mines or surface pipelines. The books reviewed were: "Means of Increasing the Effectiveness of Hydrotransport," by V. N. Pokrovskaya (1972), "Parameters and Modes of Hydraulic Transport of Coal" by V. V. Traynis (1970), and the chapter "Calculations of Hydrotransport of Useful Minerals and Waste Rock" from the book "Hydromechanization of Opencast Workings" by G. A. Nurok (1970). All three are unique and useful additions to the world literature on hydrotransport. The Traynis book reveals the development and results of circular wheel stand tests to simulate hydrotransport in horizontal pipes, which is a potentially outstanding contribution to slurry pipeline technology. Graphical data and equations are presented which suggest that headlosses for coarse coal can be predicted with good accuracy for pipe sizes up to 14 inches in diameter. Wheel stands permit tests for pipe wear and lump degradation without recycling coal through pumps. Recommendations are made for wheel stand tests and for correlation of existing data.

Jan 1, 1976

By John E. Pahlman

The Bureau of Mines conducted column-leaching tests on 25 domestic Mn ores to determine the feasibility of extracting Mn by in situ or heap leaching with dissolved sulfur dioxide (S02) solutions. The ores tested were obtained from deposits in Arizona, Arkansas, California, Colorado. Maine, Minnesota, Nevada, and South Dakota. Dissolved S02 was found to be effective for leaching Mn; extractions greater than 90 pct were obtained with solution application rates of 1 mL/min from uncalcined, minus 2.5-plus 1.3-cm ore pieces. Leaching these ores with solutions containing only 5-wt-pct S02 and no added H2S04 resulted in Mn being selectively extracted over Fe except when Fe was present as goethite or siderite. Ca solubilization was inhibited by controlling the solution application rate (1 mL/min). The rate of leaching was found to be principally dependent upon the rate at which the leaching solution can penetrate the ore, since the solubilization of Mn upon contact with S02 was observed to be rapid. Despite low water permeabilities of the ores (as low as 10-2 to 10-4 darcy). greater than 90 pct of the Mn was extracted from even the largest ore pieces tested (approximately 10 cm in diameter). It appears, therefore. that leaching Mn opens up the pores, allowing penetration of the leach solution into the ore pieces.

Jan 1, 1988

By D. J. MacDonald

This U.S. Bureau of Mines report reviews published information on synthetic berlinite (AlP04) and suggests experimental conditions requisite for its production. Berlinite is a piezoelectric material with potential use as a substitute for quartz in the crystal oscillators, which are components of electronic and electroacoustic equipment. Information gathered here (mostly from published sources) includes historical background, physical properties, end-use applications, criteria of quality, and physio-chemical factors involved in berlinite crystal growth. It is concluded that growing large high-quality berlinite crystal would require high-purity starting materials in an autoclave equipped with a noncorrodible liner and operated with temperature control of ±O.OO5 ac over a range of 250 to 350 ac.

Jan 1, 1995

In March, the Minister of Mines, Mrs. Judy Erola, released a mineral discussion paper at the annual meeting and convention in Toronto of the Prospectors and Developers Association. Among the mineral objectives discussed was the revitalization of the "junior" mining industry. That industry reportedly has seen its share of total exploration expenditures fall from 50% in 1969 to 10% in 1979. Some sources believe the reason to be the rise of exploration costs and more- restrictive legislation The junior mining industry reportedly was responsible for 40% of all mineral discoveries in the 1969-79 period. CZECHOSLOVAKIA Czechoslovakia expects its capacity for the recovery of gallium metal to increase from 1,650 kilograms to nearly 3,000 kilograms per year by the installation of new recovery equipment at the aluminum plant at Ziar Nad Hronom in Central Slovakia. World production data are not reported, but the United States consumed 8,000 kilograms (estimated) in 1981, of which 5,536 kilograms were imported. Gallium is recovered as a byproduct of the Bayer process for the conversion of bauxite to alumina, and from certain zinc processing wastes. It is used for electronic applications such as light-emitting diodes for visual display panels in calculators, clocks, and other instruments.

Jan 1, 1982

By O. C. Blade

This report on the properties of motor fuels sold through service stations in the United States was made in accordance with a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. By agreement with the American Petroleum Institute, identification of the items is confidential. It presents analytical data for 3,924 samples, representing the products of 116 companies. The samples were collected during June, July, and August, 1954. As in previous surveys, the gasolines covered by this survey include those from both large and small suppliers, The data were obtain& by laboratories of various refiners, motor manufacturers, and chemical companies and submitted to the Bureau of Mines for compilation, A list of the National Motor-Gasoline Survey reports published during the past 10 years is given on page 5.

Jan 1, 1955

By G. R. Strimbeck

Experimental work is report on the gasification of 90-percent through 200-mesh, strongly coking Sewickley-bed coal with oxygen and with steam in three temperature ranges, namely, 2,700° to 3,400° F., 1,600° to 2,000° F., and 230° to 250° F. Thirty-one runs have been made, during which 56,000 pounds of coal have been charged to the generator at feed rates of 200 to 450 pounds of coal per hour. The average results, not the optimum results, are given in the following tabulation:

Jan 1, 1950

By Holt L. Farley

This report describes the development of an electronic system which detects unsafe slack and overload conditions in underground mine hoist ropes. The Slack and Overload Rope Protection System (SORPS) includes a fail-safe load cell inserted between the rope and the conveyance, and an accelerometer mounted on the conveyance. Signals from these transducers are telemetered via a radio link to the hoist control room, where they are combined with drum speed and chair status in a microprocessor-based decision and display unit. Abnormally high external force levels are detected as discrepancies between rope tension and cage acceleration; conveyance weight is inferred continuously. Hazardous conditions are displayed to the hoist operator, along with general hoist status. The system has been tested in a working mine for approximately two years. The report contains specifications, design data and field test experience generated under the SORPS program. It also includes information on dynamic modeling, vibration environment, the status of existing slack detection systems, and applicable control strategies.

Jan 1, 1983

By Doris M. Hyde

There were no significant changes in the mineral industries of the smaller Caribbean Islands during 1980. Imported petroleum requirements continued to erode economic gains that may have occurred in other sectors. Some relief may be forthcoming as more qualified Caribbean countries take advantage of Trinidad and Tobago's petroleum product financing program (see Trinidad and Tobago). There were no crude oil discoveries in these areas during 1980, although some geophysical testing around the British Virgin Islands and Antigua war underway. In March 1980, the Government of Antigua sold a 75% interest in the 16,000-barrel- per-day West Indies Oil Co. refinery to the Swiss Intermaritime Bank and Intermaritime Management Services for $6 million. The new refinery company is called the National Petroleum Co. Shutdown since 1976, it was originally planned for the refinery to reopen in 1980, but refurbishing has proved to be more extensive than anticipated. The reopening is now expected in 1981.

Jan 1, 1982

By J. F. Neill, O&apos

[The Cartersville mining district is in Bartow County, Ga., about 40 miles northwest of Atlanta. Barite, limonite, ocher, amber, hematite, and, manganese oxide ores have been produced from the strict since about 1840. In the search for a possible source of manganese ore, Bureau of Mines engineers made a preliminary study of the district from September 1950 to January 1951. During this study 139 deposits were examined, and many mineral exposures were sampled. Manganese mineralization occurs as fine oxide and concretionary pellets in residual clays, as fine oxides in umberous clay, in brown-iron deposits, and in a limited quantity in mud ponds and Jig-tailing piles. The future supply of ferrograde manganese ore from the district, using current mining and benefication methods, appears limited to the recovery of the hard manganese ores deposits. Rough estimates indicate a reserve of manganese-bearing clays of about 8,000,000 long tons. This type of deposit has been extensively exploited and the larger deposits mined out to depths of from 50 to 200 feet. The remainder of these deposits are low grade, are covered with deep layers of colluvium, or lie below the ground-water table. Any future production from this source will require systematic prospecting, improved concentration, and an increase in the price of concentrate.]

Jan 1, 1954

By Joseph A. DeCarlo

This publication presents a tabulation of oven-and beehive-coke plants in the United States as well as pertinent statistical data on the number, capacity, kind, and condition of the ovens. Coke is an essential raw material in pig-iron production and the coal-chemical materials produced during the coking process are used to manufacture fertilizers, paints, plastics, synthetic rubber, explosives, detergents, nylon, pharmaceuticals; dyes, and many other products necessary to the high standard of living in this country. In table 1 the oven-coke plants in the United States on December 31, 1959, are listed. This shows the name and address of the company, location of the plant, classification or type of ownership, number and type of ovens, annual coke capacity, and the coal-chemical materials produced. The "furnace" plants I are those owned by iron and steel companies and most of them are integrated with blast furnaces to facilitate transportation of raw materials for steel making. Furnace plants represented 87 percent of the total coking capacity and their average annual capacity was 1. 3 million tons. The "merchant" plants are those associated with chemical companies, gas utilities, as well as those that produce metallurgical, industrial, and residential-heating grades of coke and coal-chemical materials for sale on the open market. These coke plants are smaller than furnace plants and in 1959 their average coke capacity was only 520 thousand tons annually. On December 3l, 1959, there were 54 furnace and 20 merchant oven-coke plants in existence in the United States.

Jan 1, 1960

By Thomas M. Barczak

This U.S. Bureau of Mines report is intended to assist coal mine operators in the selection of longwall supports by providing advanced guidelines for performance testing and standardized test documentation to facilitate support comparisons. These advanced guidelines culminate in a series of proposed tests to evaluate (1) support resistance characteristics, (2) stiffness characteristics, (3) leg mechanics, (4) stability, (5) load transfer mechanics, and (6) structural integrity. The Bureau has conducted extensive studies on shield mechanics to identify boundary conditions that induce loading in support components, which is often not included in current testing techniques. This report discusses influential parameters that affect support behavior and provides insight into how components are loaded and what conditions produce the most severe loading. Testing philosophies and techniques in both active and static frames are discussed. Proper methods for determining support resistance are described and instrumentation requirements for advanced performance testing are provided.

Jan 1, 1989

By D. L. Neylan

The Bureau of Mines evaluated various methods for identifying sources of mercury vapor in excess of the threshold limit value (TLV) of 0.05 mg of mercury per cubic meter of air set by the American Council of Government and Industrial Hygienists (ACGIH) for mines and mineral processing plants. Chemical spot tests and portable devices for mercury determination were evaluated, based on information from published sources and performance in laboratory tests. Among the parameters examined were sensitivity, interferences, cost, ease of use, and other factors pertinent to field application, More than 50 methods were evaluated. The investigators found that many readily available methods are suitable for identifying sources of mercury vapor in mines and mineral processing plants. The best method appears to be one that uses a commercially available mercury test paper sensitive only to mercuric ions. For some of the more promising chemical spot tests, this report includes step-by-step instructions for field application.

Jan 1, 1983

By H. P. Greenwald, H. C. Howarth

There was reported in Bureau of Mines Technical Paper 5754/ a series of tests to determine the compressibility and bearing strength of specimens prepared from blocks of potash salt obtained from a mine near Carlsbad , N. Mex . The events leading up to the investigation were sketched in a foreword by George S. Rice , then chief mining engineer of the Bureau ( retired September 30 , 1937 ) ; this foreword also gives a discussion of the possibility of increasing the ultimate total recovery of the potash salt by " second mining" of pillars or by use of a longwall system . In June 1936 , Rice and the senior author visited Carlsbad with H. I. Smith , chief of the mining division of the Geological Survey , to observe mining then in progress and to discuss with the management of one of the mines records of convergence of roof and floor which they were obtaining . It developed that serious thought was being given to the possibility of roof failure resulting from shear at the faces of pillars . There was envisioned the danger of such cracks extending upward to water - bearing strata . Obviously , the simple compression tests of the potash salt then being made would throw no light on this question , and tests of assemblies of potash and roof salts would have to be made . In this connection it is to be remembered that in the mine no sharp division exists between the potash salt being recovered and the nearly pure halite which forms the roof . The interlocked crystalline structure is continuous , and there is merely a very rapid decrease in the proportion of sylvite in a short distance vertically . Figure 2 of Technical Paper 575 shows that two samples near the top of the salt being mined contained , respectively , 51 and 65 percent potassium chloride . Contrasted with this is an analysis of the roof salt given on page 24 of that publication , which showed only 3.6 percent potassium chloride . As the data given in Technical Paper 575 show , the roof salt is much less plastic than the potash salt . The immediate roof may then be thought of as a more rigid stratum of indefinite extent resting on and continuous with yielding supports and loaded uniformly at the rate of 900 to 950 pounds per square inch . Just what thickness of the salt should be considered as immediate roof is uncertain .

Feb 1, 1938

By Carl Rampacek

The conversion of dilute sulfur dioxide gas into sulfuric acid by autoxidation in mechanical cells of the flotation or gas absorber types was investigated. Bench-scale tests were made with sulfur dioxide-air mixtures to determine the influence of several factors on autoxidation of sulfur dioxide, using iron and manganese salts as catalysts. The laboratory investigation subsequently was extended to pilot plant acid-making tests, using a modified turbomixer gas absorber having a 12-inch-diameter impeller. Sulfur dioxide gas was produced for the tests by roasting pyrite in a fluidized-bed reactor. In the better tests, made with manganese sulfate as the catalyst, the equivalent of 1,000 pounds of anhydrous H2SO4 was produced per 24 hours as a 10-percent solution; power consumption was 0.2 kwhr per pound of equivalent anhydrous acid synthesized. The batch and continuous tests demonstrated the technical feasibility of producing dilute sulfuric acid by autoxidation of sulfur dioxide gas in mechanical cells when converting pyrite roaster or waste smelter gases.

Jan 1, 1963

By [F. P. ] Stambaugh

Results of research on the hydrothermal precipitation of zirconium oxide from the Bureau of Mines' zirconyl chloride-sulfate strip liquors indicate that nuclear grade material can be prepared by this process. Greater than 99% of the zirconium value can be precipitated at 250-260°C in short (5-10 minutes) reaction time without consumption of acid value of the liquor. Thus, precipitation of zirconium dioxide on a continuous basis, i.e., the zirconium dioxide is precipitated in a continuous mode of operation by pumping the strip liquor through a heated pressurized reactor and recycle of the acidic (spent) liquor to the process stage are favored. The results of accompanying studies of liquod/solid separation, product washing and dewatering, product purity, and chlorination of the product are presented and discussed.

Jan 1, 1980