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By Fred W. Snow

This paper describing the mining practices at the Magma mine, Superior, Ariz., is one of a series being prepared by the Bureau of Mines on mining prac¬tices, methods, and costs in the various mining districts in the United States. At present (1929) practically all the mineral production in the Superior district is from the Magma mine of the Magma Cooper Co. The ore is mined for its copper but contains associated silver and gold. Both direct smelting ore and ore of concentrating grade are produced. The mining methods now in use at the Magma mine were adopted or developed as knowledge was gained of the physical condition of the ore bodies and the inclosing formations; the wall rock is soft and crushed and the ore is relatively hard. In general, existing methods have been adapted to fit local conditions, but some of the mining practices used were originated at this mine. Most of the ore is mined by a combination of rill stopes and pillar stopes. The pillars are extracted by underhand mining.

Jan 1, 1929

By C. F. Jackson

This paper describing the mining practices at a mine in the Southeast Missouri district is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The conditions, operating methods, and practice described in the following pages arc those obtaining at a property in the Southeastern Missouri lead belt, St. Francois County, Mo. This property is the eldest in the county and is a consolidation of a number of separate mines originally opened up as individual operations many years ago. Present-day operations have necessarily to be adapted to suit the older levels, stones, and pillars, and also the recovery of ore from worked over areas which was considered too low grade to mine in the earlier days constitutes a different problem than that of development and mining in virgin ground.

Jan 1, 1929

A complete list of permissible mining equipment, rescue apparatus and gas masks tested. Prior to Jan. 1, 1929, w s published in Bureau of mines Information Circular 60972. The present list includes practically all equipment tested and. approved by the Bureau, up to and including July 1, 1929. It covers electric air compressors, coal drills, mining machines, loading machines, conveyors, mine pumps, room hoists,, mine telephones, rock-dusting machines, switches, electric cap lamps, flame safety lamps, electric hand and trip lamps, flash lamps, methane indicators and detectors, blasting units, storage battery locomotives, tandem locomotives, power trucks, concrete mixers, self-contained oxygen breathing apparatus and gas masks. The system under which these devices were tested permits the manufacturer, after his equipment has passed certain tests prescribed by the Bureau of Mines, to mark his equipment with a seal showing hat it has been "approved" by the Bureau. These tests are designs to insure that the equipment has the minimum requirements for safety in use. The only object of the Bureau in making such tests and publishing lists of permissible equipment is to safeguard the lives of workers and to help lessen the hazards of mining.

Jan 1, 1929

By B. Numerov

A numerical proceeding of corrections with respect to topography is worked out for places near the station and a graphical one for the remote parts of the terrain. The description is clear and very detailed. The numerical proceeding is very similar to that of the Eötvös and Schweydar methods which are in use already. In both methods the levelling is accomplished in certain circles and fixed azimuths around the station. While, in using the Eötvös method, the height differences are directly inserted into the final formulas with regard to the foot of the instrument and in case of accurate formulas derived by Schweydar the height differences are calculated with respect to the center of gravity of the attachment, Numerov introduces functions A and B, the heights, of the terrain and of the center of gravity, which are to be inserted into the formulas.

Jan 1, 1929

By Emory Smith

The Victorville cement plant of the Southwestern Portland Cement Co. is located about 1 mile from the city of Victorville, Calif. Two transcontinental railway systems, the Atchison, Topeka & Santa Fe, and the Southern Pacific Railroad, afford shipped facilities. The plant is modern and well kept, as the officials, especially the higher operating officials, take pride in the appearance of the place. Dust has been practically eliminated by the installation of dust collectors and wet grinding. The plant has a rated capacity of 5,000 barrels of cement daily.

Jan 1, 1929

By E. H. Denny

Colorado coal-mine fatalities, which have gradually decreased since 1914, have shown a marked decline since 1924. Data on coal-mine fatalities in Colorado published by the U. S. Bureau of Mines5 indicate that the deaths per thousand 300-day workers have decreased from 9.13 in 114 to 6.14 in 1926, and that the deaths per million tons produced have decreased from 9.18 in 1914 to 4.98 in 1926. Table 1 gives fatality rates in Colorado and in the United States from 1914 to 1926 inclusive. [ ]

Jan 1, 1929

By D. Harrington

The coal-mining industry of the United States finds difficulty not only in making ends meet financially but also in operating with anything like reasonable safety. The record to date has not been particularly good as to either finance or safety, but at least in some phases or safety there are indications of better times to come. During the fiscal year ending June 30, 1929, only 139 lives were lost in explosions in our mines as against 342 lost during the fiscal year ended June 30, 1928; this decrease in such fatalities is definitely a matter for satisfaction. During the fiscal year July 1, 1928, to June 30, 1929, the attention of the safety division of the U. S. Bureau of Mines was directed to 38 mine explosions in the United States. Two explosions were in non-coal mines, one in a semianthracite mine, two in anthracite mines, and 33 in bituminous mines. These were not all major explosions - that is, explosions in which five or more lives were lost; in some of the explosions no lives were lost, while in others fewer than five fatalities resulted. Table 1 gives data on the explosions, showing the number of mines using open or closed lights and the number of explosions with resulting deaths, by causes, for each State.

Jan 1, 1929

By Lucien Eaton

This paper describing the mining practices at Mine No. 2 of the Marquette Range, Michigan is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various minim; districts of the United States. The publication, of this information should be of interest to the industry at large and the exchange of ideas thereby made possible should be of economic value to operators in all harts of the country. ACKNOWLEDGMENTS The author is indebted to the superintendent, engineer, and mining captain of the property discussed in this paper for much of the information presented. The geological classification is taken from publications of the U. S. Geological purvey.

Jan 1, 1929

By Lucien Eaton

This paper describing the mining practices at Mine No. 1, Menominee Range, Mich., is one of a. series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. It is felt that the publication of this information will be of interest and value to the mining industry at large and especially to operators whose mining conditions are similar to those described. ACKNOWLEDGMENTS The author is indebted to the superintendent, engineer, and mining captain of Mine No. 1 for much of the information presented.

Jan 1, 1929

By Paul M. Linebarger

This paper is one of a series of digests of foreign mining legislation and court decisions prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Mexico has been pro oared from the best information available in Washington but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers, to whom it has been referred through the courtesy of the Department of State. INTRODUCTION Present-day Mexican mining legislation involves, not only the latest minim enactment (August 1, 1026), but many other enactments and regulations, principal among which are the Constitution, the Civil Code, the Code of Commerce, the Foreign Law, the Mining Tax Law, and. the Civil Jurisprudence of Mexico--the last-mentioned being based in Dart on Supreme Court decisions. Ere Mexican Federal Government is supreme in mining legislation because, among other reasons, a large part of the revenue of the Government must come from the fiscal control of the mines. All circulars, decrees, and rulings that affect the mines not only have their origin in the Central Government but are administered thereby. The Department of Industry, Commerce, and Labor is in control of all mines. Attention may here be called, however,

Jan 1, 1929

By Paul M. Tyler

This paper is one of a series of digests of foreign mining legislation and court decisions 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 Yugoslavia was prepared from information furnished by John Dyneley Prince, American Minis- ter at Belgrade, in response to a questionnaire submitted by the Bureau of Kinos and transmitted through the courtesy of the Department of State.

Oct 1, 1929

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 Guatemala 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.

Oct 1, 1929

By John W. Frey

This paper is one of a series of digests of foreign mining legislation and court decisions prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of cw Zealand, as prepared by Dr. Frey the best available information in Washington, has been slightly amplified in accordance with suggestions transmitted through the courtesy of the Department of State by W. L. Lowrie, Consul General at Wellington.

Oct 1, 1929

By P. R. Bradley

This paper is one of a series , dealing with mining methods and costs , sponsored and published by the U. S. Bureau of Mines . Papers of this series are written by engineers and executives of mining companies , at the solicitation of the Bureau , and in accordance with an outline prepared by Bureau engineers , for the purpose of securing uniform presentation and conformable data . The property of the Alaska Juneau Gold Mining Co. is situated near the city of Juneau , Alaska , in what is known as the Harris mining district . Wholesale mining operations have been adopted on a large scale and 10,000 to 11,000 tons per day of gold- bearing ore are mined and sent to concentrators near Juneau . In addition to gold , the ore yields 0.6 ounce of silver and 13.0 pounds of lead to each ounce of gold recovered .

Oct 1, 1929

By F. S. Crawford

Interesting data on electric blasting and sinking of the Montreal No. 5 shaft of the Montreal Mining Co., Montreal, Wis., were obtained during the sinking of the last 877 feet of this shaft. Several unusual features and safety practices are also to be found in the Montreal mine. The Montreal shaft was sunk 2,156 feet from August 16, 1921, to May 1, 1924, and 877 feet from October, 1927, to June, 1928. The first section of the shaft was supported with steel sets spaced 5 feet on centers; and instead of lagging the walls were covered with three-eighths of an inch of gunite where Greenstone was encountered, and where quartz-slate was found (from the surface to the 12th level) the walls were lagged with tamarack lath treated with carbolineum, a preservative.

Jan 1, 1929

By F. E. Cash

"In the interest of accident prevention it is felt that a report of the measures taken during the past four years toward the reduction of fatal accidents in Alabama, especially in preventing falls of roof and coal, will be of interest throughout the mining districts.In order to determine the primary factors in the reduction of fatal accidents from falls of roof and coal, the operators, State Inspection Department, and the Alabama council of the Holmes Safety Association were asked: ""What has your organization done to help in the reduction of accidents from fails of roof and coal?"" The responses to this question have made this report possible.To bring out briefly the reduction in fatal accidents from falls of roof and coal as well as from all causes, the following three tables have been prepared.These statistics have been compiled from the records of the State Inspection Department.In the order mentioned, it is felt that credit for the reduction in fatal accidents from falls of roof and coal should be given to the individual operating companies, the State Inspection Department, the Alabama council and chapters of the Holmes Safety Association, and the Alabama Mining Institute. The individual operating companies naturally head the list in that they are directly concerned from a humanitarian as well as a financial point of view. The State Inspection Department through frequent and thorough inspections and by providing necessary statistics is largely responsible for the reduction. The Alabama council and its affiliated chapters of the Joseph A. Holmes Safety Association through its publicity and education reaches a large number of employees throughout the mining district. The Alabama Mining Institute defrays the council expenses and thus makes possible much of this service to the Alabama mining industry.In 1925 there were 49 fatalities, equivalent to 115,169 man days per fatality, from falls of roof and coal, which was by no means a good record; in 1926 the number and frequency of accidents were reduced to 42 fatalities and 149,096 man days per fatality. When in 1927 the fatalities from this cause mounted to 61 and the man days per fatality were reduced to 89,903, it was quickly realized that more concentrated efforts must be exerted to reduce such accidents.As early as August, 1927, at which time the fatalities from falls had reached a total of 31, the following letter from the Chief Mine Inspector was written to each operating company in the State and was the initiation of a very strenuous campaign by all parties concerned towards the reduction of accidents from falls of roof and coal."

Nov 1, 1929

By John W. Frey

This paper presents one of a series of digests of foreign mining legislation and court decisions that 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 Persia 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 .

Nov 1, 1929

By Chas. F. Jackson

This paper is published as a progress report for the first half of 1929 on the study of wining methods and costs in the Eastern and Central States. Data obtained from 25 mines using open-stope methods are correlated and summarized. Some of these mines have been described in considerable detail in reports already published as Information Circulars. In addition to the published reports on individual mines, considerable data have been obtained from other mines which were visited and studied during the course of the investigation. Many of these mines will later be described in detail in separate papers, and when the field has been covered in this manner it is planned to issue a bulletin on open-stops methods of mining which will amplify the subject matter of the present paper. Definition of ?Open-Stops?. - The term "open-stopes" as employed by the Bureau of Mines is applied to all naturally supported stopes; that is, stopes in which the excavated ore is not replaced by support of an artificial nature other than preps or stulls and in which the ore or (and) capping are not caved during the active life of the stopes.

Jan 1, 1931

By A. U. Miller

The added hazards to mining incident to oil and gas wells penetrating the coal measures in proximity to mine workings , have long been recognized in those fields where the extraction of oil , gas , and coal , has been in progress for a number of years . The history of these fields is replete with stories of serious mine fires , explosions , and miraculous escapes from both fires and explosions due to either oil or gas finding its way into the mine workings through the strata , or by mining into an unknown or uncharted and abandoned oil or gas well that had not been properly plugged . The Director of the Bureau of Mines , in response to numerous requests from coal operators and oil and gas operators , called a meeting in 1913 to discuss necessary precationary measures to take when drilling oil or gas wells through workable coal beds and to try, if possible . to formulate a set of regulations that might serve as a guide to those persons preparing regulations covering the drilling of oil and gas wells in the various coal producing States . This meeting was attended by representatives of the coal , oil , and gas industries , State geologists , State mine inspectors , and representatives of the Bureau of Mines . A committee was appointed to prepare a set of regulations , which was later published as U.S.Bureau of Mines Technical Paper 53 ; the discussions and results of the meeting werepublished as U. S. Bureau of Mines Bulletin 65 . Later , the American Institute of Mining and Metallurgical Engineers appointed a committee to draft a model law for the use of the legislature of any State concerned . This committee made its report on April 27 , 1928 . Several of the coal mining States now have more or less comprehensive regulations governing the drilling of oil or gas wells through workable coal beds , others have regulations that are inadequate , while some have no regulations . The State of West Virginia recently enacted a law containing reg lations which are the result of a comprehensive and careful study of the problem .

Nov 1, 1929

By R. R. Sayers

The added hazards to mining incident to oil and gas wells penetrating the coal measures in proximity to mine workings , have long been recognized in those fields where the extraction of oil , gas , and coal , has been in progress for a number of years . The history of these fields is replete with stories of serious mine fires , explosions , and miraculous escapes from both fires and explosions due to either oil or gas finding its way into the mine workings through the strata , or by mining into an unknown or uncharted and abandoned oil or gas well that had not been properly plugged . The Director of the Bureau of Mines , in response to numerous requests from coal operators and oil and gas operators , called a meeting in 1913 to discuss necessary precationary measures to take when drilling oil or gas wells through workable coal beds and to try , if possible . to formulate a set of regulations that might serve as a guide to those persons preparing regulations covering the drilling of oil and gas wells in the various coal producing States . This meeting was attended by representatives of the coal , oil , and gas industries , State geologists , State mine inspectors , and representatives of the Bureau of Mines . A committee was appointed to prepare a set of regulations , which was later published as U.S.Bureau of Mines Technical Paper 53 ; the discussions and results of the meeting werepublished as U. S. Bureau of Mines Bulletin 65 . Later , the American Institute of Mining and Metallurgical Engineers appointed a committee to draft a model law for the use of the legislature of any State concerned . This committee made its report on April 27 , 1928 . Several of the coal mining States now have more or less comprehensive regulations governing the drilling of oil or gas wells through workable coal beds , others have regulations that are inadequate , while some have no regulations . The State of West Virginia recently enacted a law containing reg lations which are the result of a comprehensive and careful study of the problem .

Nov 1, 1929