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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 A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of Japan has been prepared from the best available information in Washington but is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State . It is based on the law and regulations of 1905 as revised in December , 1915 , and translated by J. de Becker , LL.B. Occasional words and phrases quoted herein are accordingly taken from this translation and have not been checked against the original . The references are to the law ( as distinguished from the regulations ) unless otherwise stated .

Jul 1, 1930

By Edmund S. Leaver, Charles E. Van Barneveld

In response to numerous requests from metallurgists and operators for information regarding the status of the sulphur dioxide leaching process , developed at the Southwest experiment station of the U. S. Bureau of Mines , Tucson , Ariz . , the following statement has been prepared . A more complete report is now in course of publication and will appear as Technical Paper 312. This process was devised to provide a cheap and efficient method for treating the so- called "porphyry " copper ores of the Southwest which generally contain both " sulphide " and "nonsulphide " copper minerals , mixed in such proportions that they can only be satisfactorily treated by a method which will concurrently recover both the sulphide copper and the nonsulphide copper . The latter term has been adopted to include all the minerals commonly referred to in operating phraseology in the mills of the Southwest as " oxidized" , " oxide " , or " soluble " copper . confident that the sulphide dioxide leaching process , as developed by us with the cooperation of the Miami Copper Co. and the Arizona Copper Co. , is suitable and commercially available for a wide range of ores .

May 1, 1922

By D. D. Hamilton

The ISMS program provided for the development and demonstration of equipment modifications for improved safety in both conventional and continuous coal mining systems. This report documents the success of the program in identifying accident hazards in underground coal mines with 4-to 8-foot seam heights, in designing modifications to reduce the hazards, and in demonstrating improved safety through extended underground use of the ISMS equipment.

Jan 1, 1977

By Laxman S. Sundae

In the vast majority of American coal mines, roof bolt holes are drilled dry, mainly because of mine operator concern with the spent water creating adverse working conditions. Wet drilling, however, can increase drilling rates and the effective lifetime of the drill bits used. This study, carried out as part of an ongoing cooperative research program between the U.S. Bureau of Mines and the University of Missouri-Rolla, shows that the large volumes of water conventionally used in wet drilling are not necessary, and the performance benefits from wet drilling can be achieved with total volume flows on the order of 0.4 L per hole. This conclusion is validated based on the measured respirable dust generated in drilling Berea sandstone. The results are confirmed using a variety of bit shapes, which are also shown to have a significant effect on penetration rate.

Jan 1, 2010

By P. N. Summerfield

This report describes the first phase of a general investigation designed to ascertain whether an electronic roof-testing device can be developed that will improve the ability to detect "loose" or "drummy" roof rock over that possible by striking the roof with a sounding bar and noting the character of the air vibrations with the unaided ear or the rock vibrations with the fingers. The amplitude, frequency content, and duration of the vibrations produced by striking solid and drummy roof rock with a hammer or sounding bar have been measured. Results disclosed that there is a significant difference between the characteristics of the vibrations produced in solid and drummy roof. This difference is such that the design of an electronic device to indicate quantitatively the condition of the roof rock appears possible. INTRODUCTION The conventional method of roof testing consists of striking the roof with a bar2/ and judging its soundness from the character of the air vibrations heard with the ear and/or the rock vibrations felt with the fingers -a procedure that depends upon the experience and the sensory abilities of the observer. Impact testing of a solid roof rock usually produces a sharp ping or click, whereas impact testing of a drummy roof rock produces a dull thud or drummy sound. This method of roof testing is, at most, only a qualitative test, and many roof rocks are difficult to classify as drummy or solid.

Jan 1, 1956

By H. F. MILLE, Charles A. Kumke

This paper describes mining operations at the Iron King mine of the Shattuck -Denn Mining Corp. in Yavapai County , Ariz . It is one of a series being prepared by the Mining Division of the Bureau of Mines on mining practices and methods in various mining districts of the United States . The mine and surface plant of the Iron King mine are situated in secs . 15 and 21 , T. 13 N. , R. 1 E. , about 20 miles by State highway 69 east by southeast from the city of Prescott and 1 mile southwest of the mining town of Humboldt on the Prescott -Mayer branch of the Atchison , Topeka & Santa Fe Railroad (fig . 1 ) . A l-mile truck haul brings the mill concentrates (lead and zinc ) to bins on a siding of this line at Humboldt ; the silver -gold bullion is handled separately . Some of the oldest residents in the vicinity of Prescott claim that the original location for the Iron King mine was made in 1880. The earliest recorded production was in 1906-1907 . During the first World War the mine produced fluxing ore for the Humboldt smelter . In 1936 the property was purchased under tax sale , and a mill (140-ton capacity ) was erected in 1938. The capacity of this mill was increased to 225 tons the following year , and a cyanide plant was added in 1940 to treat mill tailings . In 1942 the Shattuck -Denn Mining Corp. purchased the property . A new working shaft was sunk , mine development was speeded , and mill capacity was again increased . The predominating locally formation of this district is a pre -Cambrian schist known as Yavapai schist . The Iron King deposit , which carries gold, silver , lead , zinc , and copper , occurs as a series of lenses in a sheared zone of the pre -Cambrian schist . Down to the 600 -foot level the ore was mined and drawn by the shrinkage method . The cut -and -fill method was adopted for the lower levels . Waste rock for stope fill was provided by block-caving an area on the 600 level . Main haulage drifts were driven in the firm footwall , and crosscuts were driven across the mineralized zone at 100 -foot intervals . Grab samples taken from each car of every working place and channel samples cut every 5 feet in development work are considered sufficient for estimating ore reserves .

Jan 1, 1950

By Harold J. Polta

This Bureau of Mines publication considers the feasibility of augmenting the present transportation system by pipelining taconite concentrates from the Mesabi Range to the Chicago area. The cost of pipelining in the hypothetical system using water as the carrier is estimated to be between $3.66 and $3.97 per long ton. This appears competitive with the 1970 rail-vessel transportation rate of $4.08 even after allowing a few cents per ton for barging from the terminal to existing furnaces. Political obstacles requiring solution before such a pipeline could be built and the feasibility of using crude oil as the carrier fluid are also discussed. FORTRAN routines used to calculate unit transportation cost for specific estimated values of cost items and for a range of values are presented. The effect of deviations from estimated values of cost items on the total unit transportation cost are shown graphically.

Jan 1, 1971

By Jr. Herty

Ferromanganese continues to be an indispensable requirement in steel manufacture. Approximately 470,000 of the 80 per cent ferro-alloy was consumed in 1929 and increasing amounts will be required annually by the steel industry unless some satisfactory substitute is found. An average of 14 pounds of metallic manganese is used for each ton of steel produced, The principal use of manganese is for de-oxidation of the metal in the steel refining processes, although a considerable amount is also used for the production of special manganese steels. Unfortunately, domestic production of manganese ore is inadequate to meet normal peace-time requirements, not to mention increased abnormal war-time demands. The rather large quantities of low-grade manganiferous iron ores which occur in the Coruna Range in Minnesota have for a number of years greatly appealed to those interested in the development of a domestic source of the supply. The North Central Experiment station of the Bureau of Mines has made an elaborate study of the possibilities of the pyrometallurgical treatment of ores from these deposits and much of the valuable information secured by them has already been published.

Jan 1, 1930

By Doris M. Hyde

The Bahama's petroleum-dominated minerals sector constricted again in 1985. The declines were mostly the result of a soft market demand for crude oil and petroleum products. In early 1984, it was a growing unprofitability that prompted Charter Oil Co. to cease using the 350,000-barrel-per-day Bahamas Oil Refining Co. facility that it jointly owns with Chevron Oil Bahamas Ltd. After midyear 1985, because of poor petroleum economics, Chevron announced it would close the refinery, leaving only a maintenance crew. In 1984, the refinery exported less than 26 million barrels of petroleum products. Chevron's throughput was reported as averaging about 8,000 barrels per day at the time of the announcement. The crude oil transshipment terminal also registered declining activity and financial losses in 1984 and 1985. Transshipments of petroleum in 1985 amounted to about 100,000 barrels per day, one-half as much as in 1982.

Jan 1, 1987

By R. J. Pokora

This Bureau of Mines report is an applications manual that can be used by the nonmetallic mining industry for guidance in installing noise control materials into crushing and screening plants. These noise control modifications were installed and successfully tested at three operating quarries. This report identifies the major noise sources that can be encountered in crushing and screening plants, and discusses the applicable noise control materials and techniques that a plant operator can utilize on a retrofit basis to reduce equipment noise.

Jan 1, 1984

By K. O. Bennington

Cancrinite is one eonstituentof "red muds," a high-volume waste product of alumina production by the Bayer process. The Bureau of Mines determined the thermochemical properties of cancrinite as part of a program to provide such data for minerals of industrial importance. Cancrinite [Na7.68(A16Si6024)(N03)1.68 (H2O)4.1] was synthesized by reacting aluminum silicate gel with a solution of NaOH and NaN03, and the composition was determined by chemical analysis, differential scanning calorimetry, and thermogravimetric analysis. The heat of solution was determined by hydrofluoric acid solution calorimetry. The standard enthalpy of formation at 298.15 K, ?Hf°298, is ?Hf°298 = -3,487.97 ±2.6 kcal/mol, and the standard enthalpy of formation from the oxides and NaN03, ?H°298, is ?H°298 = -215.20 ±l.8 kcal/mol.

Jan 1, 1983

By Robert G. Bottge

The Bureau of Mines has engaged m a program to determine the availability of land for mineral exploration and development in Alaska. Land availability, based on ownership and Federal and State laws and policies, is compared with mineral terranes and mineral deposits. This is the fifth of six regional studies, which cover the State with a comprehensive set of maps and data compilations. This study covers an area of 112.3 million acres in western Alaska. In July 1986, 41.0 million acres, 37% of the study area, were available for mineral exploration and development; 14.6 million acres, 13%, were available with restrictions; and 56.7 million acres, 50%, were unavailable. Nearly 65% of the unavailable land is classified as national parks, preserves, wildlife refuges, and wild and scenic rivers. Of the 34.0 million acres of mineral terranes that underlie the study area, 12.9 million acres, 38%, are available for exploration and development; 3.6 million acres, 11%, are available with restrictions; and 17.5 million acres, 51%, are unavailable.

Jan 1, 1988

By Thomas P. Mucho

Retreat or pillar recovery mining redistributes the overburden weight onto the adjacent coal pillars in a room-and-pillar section. The additional stress and the resultant energy stored in the remaining pillars can become so great that pillars may bump or violently fail. An investigation at the Gary No.2 Mine was conducted to examine the effectiveness of the thin pillar mining method for mitigating bump occurrences. Field observations were made and instruments were installed to monitor pillar behavior during extraction. Stress monitoring instruments and roof-to-floor convergence stations were installed in pillars and entries and crosscuts, respectively. Results indicated that high pillar stress concentrations occurred in these bump-prone geologic conditions. The thin pillar mechanism, the creation and progressive outby movement of an expanded yield zone, was also monitored through the instruments. The expanded yield zone, a result of using thin pillars in a highly stressed pillar line area, mitigates bump risk.

Jan 1, 2010

By A. Y. Lee

Prior work at the Bureau of Mines resulted in the successful development of a bench-scale, combination electrorefining-electrowinning method for recycling the lead from scrap batteries using waste fluosilicic acid (H2SiF6) as electrolyte. This paper describes larger scale experiments. Anodes cast from scrap battery lead were electrorefined in a 20-L multielectrode cell for 3 to 7 days. The anodes, containing 2 to 2.5 pct antimony, were ideal for obtaining firm and adherent slime blankets. Cathode deposits, assaying 99.99 pct Pb, were obtained, with current efficiencies near 99 pct. Sludge leaching was done in 100-L tanks followed by filtering in 61 cm square vacuum pan filtersu Lead of greater than 99.99-pct purity was recovered from the filtrate by electrowinning in a 20-L multielectrode cell using insoluble Pb02-Ti (lead dioxide-coated titanium) anodes and pure lead cathodes. The fluo-silicic acid electrolyte depleted in lead was repeatedly recycled to leach more sludge, and there was no problem with impurity buildup. The amount of Pb02 formed on the anodes during electrowinning was less than 1 pct of the total lead deposited on the cathodes, as long as the phosphorus concentration in the electrolyte was greater than 1.3 giL. Emissions of lead in air were less than 10 ~g/m3, well below the proposed OSHA limit of 50 ~g/m3.

Jan 1, 1984

By J. M. Mutmansky

"This study analyzed laboratory comminution techniques for respirable mine dust generation and the properties of the resulting dusts. It was the objective of the study to determine the suitability of the resulting dusts in reflecting the properties of natural airborne dust. This paper deals specifically with the amount of contamination introduced into the generated dust as a result of abrasion when using nine different grinding methods. The analysis was made by comparing the content of 25 chemical elements in the lab-generated dusts with the same elements in the airborne coal mine dusts. It was found that all the lab-generated dusts possessed contamination but that several methods produced smaller percentages of contamination and that the residence time in the grinding device was an important factor in the contamination levels. INTRODUCTIONDust in the atmosphere is a health hazard and a major source of occupational diseases in the coal mining industry (Anon., 1980; Merchant, Boehlecke, and Picket-Hamer, 1986). It has been shown that coal workers' pneumoconiosis (CWP) is directly related to the inhalation and accumulation of respirable coal dust in coal miners' lungs. In order to effectively protect coal workers from coal dusts, we must have a clear understanding of dust properties including dust generation and dust-lung reaction mechanisms. This requires extensive biomedical research. Dust related research often requires large samples of respirable coal dusts to be collected, either for repeated experiments or stored for future reference. Unfortunately, current sampling instruments are not able to meet this demand. Ali a result, laboratory-generated coal dust ls frequently used as a substitute for coal mine dust in biomedical and other research applications. Now, the questions are how close the characteristics of laboratory-generated dusts are to those of mining-generated dusts and which equipment is moat appropriate for research dust production in the laboratory . These are some of the interests of this research project. The primary objective of this project was to find a laboratory technique which can generate coal dusts possessing properties similar to coal mine dust with respect to particle size distribution, chemical composition, and particle shape and morphology. However, this paper will focus only on the chemical compositions of the prepared dust samples and try to identify the sources of chemical contamination from various size reduction processes."

Mar 1, 1992

By D. B. McGilvra

This paper, describing the mining practices and methods at the Black Rock mine, is one of a series of similar papers on mining methods in the various mines of the United States being prepared by the Bureau of Mines. The Black Rock mine is located in the northeast corner of the Butte district, about 3 miles from the center of the town of Butte, and is owned and operated by the Butte & Superior Mining Co.

Jan 1, 1930

By Thomas Mucho, Anthony Iannacchione

This marks the 100th year that the aggregate industry has been served by a national association. Of all the accomplishments this longstanding relationship has achieved, there is probably none greater than the progress made, in worker safety. Perhaps the best way to measure this success is to examine injury trends in the aggregate miner population. For example, in the first half of the 20th [ ] century, 16 quarry mining disasters (a "disaster" is an incident with five or more fatalities) claimed 157 miners between 1909 and 1952. The largest of these was the disaster at the Sandts Eddy Limestone Quarry near Allentown, Pa., on March 26, 1942, where 31 miners died of asphyxiation by fumes/explosion. Thankfully, no mining disasters have occurred in the aggregate industry since 1952. It is these kinds of information that help us characterize improvements in aggregate worker safety over the last 100 years.

Jan 1, 2003

By C. C. Popoff

This report reviews the phosphate deposits, mines, and industry, and prospects in 10 districts covering most of the Montana phosphate field. These districts are discussed individually, and an evaluation of the resources and potential of each is presented. Phosphate rock produced from underground mines in the Garrison district is shipped to Canada for processing to fertilizers, utilized locally for production of animal feed supplement, and pulverized and sold for direct application to the soil. Production from the Melrose district is shipped to Silver Bow and processed to elemental phosphorus. The Maxville-Philipsburg district is destined to become a major producer with the development of the Douglas Creek mine and beneficiation plant by Montana Phosphate Products Co. Montana ranks fourth after Florida, Tennessee, and Idaho in total annual production in the United States. Production him increased from about 60,000 long tons of acid-grade phosphate rock in 1940 to more than 660,000 tons of acid-, beneficiation-, and furnace-grade ore in 1961. Montana has the second largest potential resources in the Western field; in the area south of Butte there are approximately 1.2 billion tons of phosphate rock (+18 to +31 pct P2O5) available above and within 100 feet below entry level; and in the northern part of the field there are about 67.6 million tons available above entry level. In contrast to Idaho, most of the phosphate deposits in Montana are best suited to underground mining.

Jan 1, 1965

By G. Asai

The purpose of this Bureau of Mines investigation was to determine the properties of arc-melted iron-chromium alloys ranging in chromium content from 12 to 50 wt.-pct. Alloys were prepared by consumable-electrode arc melting of electrodes composed of high-purity chromium and high-purity iron. Alloys were fabricated to rod and sheet, and the following data were obtained: Electrical resistivity, hardness, tensile strength, and impact strength at room temperature; and creep-rupture life at 650° C. (1,200° F.). As the chromium content of the annealed alloys varied from 12 to 50 pct., the properties varied as follows: The electrical resistivity increased proportionally from 41 to 53 microhm-cm,; the Rockwell hardness varied from A 38 to A 58; the tensile strength ranged from 52,000 to 96,000 p.s.i.; the impact strength of V-notched charpy specimens varied from 140 to 405 ft.-lb., and the 100-hour creep rupture life at 1,200° F. varied from 5,000 to 16,000 p.s.i.

Jan 1, 1962