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By James Spiers

This paper describing the mining practice at the Central-Eureka mine is one of a series of similar papers being prepared by the United Staten Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The mining practices described in this paper are illustrative of the methods employed in the exploitation of comparatively low-grade gold ores under the extremely heavy and swelling ground conditions which occur in the Mother Lode belt of California. The Central-Eureka Mining Co. comprises a group of adjoining mines in Amador County near Sutter Creek. The principal mines of the consolidated group are the Central-Eureka, formerly known as the Summit mine, and the Old Eureka mine, which is also known as the Hayward Quartz mine. The group is situated in the most productive part of tae main Mother Lode belt, the 10-mile portion which lies between the towns of Plymouth and Jackson. The three largest producing mines of the entire belt at the present time are the Argonaut, Kennedy, and the Central-Eureka; these lie within a radius of less than 1-1/2 miles.

Jan 1, 1931

By M. M. Tilman

The Bureau of Mines evaluated corrosion resistance of Split Set friction rock stabilizer mine roof bolts to aid in better prediction of useful service life. Electrochemical corrosion testing was conducted utilizing an automated corrosion measurement system. Natural and/or synthetic mine waters from four uranium and two copper mines were the test media for the two types of high-strength, low-alloy (HSLA) steels from which Split Set stabilizers are manufactured, and for galvanized steel. Tests were conducted with waters of minimum and maximum dissolved oxygen content at in-mine water temperatures. Retrieved Split Set stabilizers were also evaluated for property changes. Galvanized steel was found to be far superior to the unprotected steel in general corrosion resistance; limited tests indicate little ten.dency to pitting, contrary to behavior for the uncoated steel. Copper-bearing HSLA steel was slightly more corrosion resistant than non-copper-bearing HSLA steel. Statistical analyses resulted in development of equations relating dissolved oxygen, chloride, sulfate, and magnesium contents of mine waters to corrosion rates of the two HSLA steels (nongalvanized). An equation was developed that relates corrosion rates of galvanized steel to mine water temperature and dissolved oxygen content. Variable conditions in mine environments make corrosion damage difficult to predict and emphasize the need for corrosion prevention and control.

Jan 1, 1984

These tentative inspection standards have been prepared as a guide for the Federal inspection of the anthracite mines of the United States. The Federal Coal Mine Inspection Division is not a mining-law-enforcement

Jan 1, 1943

By E. M. SEELEY, F. S. LOTT

The total capacity of the natural-gasoline industry to produce light hydrocarbon products increased to 21,322,000 gallons ( 507,670 barrels ) daily on January 1 , 1948 , from 17,928,000 gallons ( 426,860 barrels ) daily on January 1 , 1946. Expansion of the industry in the first two post -war years , 1946 end 1947 , thus averaged 9 percent annually , compared with 6 percent annually in the last two war years , 1944 and 1945 . The number of cycle plants increased only from 37 to 39 in the years 1946 and 1947 , and total capacity of these plants gained 21 percent to 5,857,000 gallons de ily on January 1 , 1948 , represent ing 27.5 percent of the total capacity of the industry , compared with 27.0 percent on January 1 , 1946. All other plants decreased in number in the two-year period from 589 to 510 on January 1 , 1948 , but their total daily capacity increased 18 percent to 15,465,000 gallons . The daily capacity of the average plant in the industry was enlarged from 28,600 gallons on January 1 , 1946 , to 38,800 gallons on January 1 , 1948 , continuing the long -established trend to producing units of greater size and efficiency . The average cycle plant capacity increased from 131,000 gallons daily to 150,200 gallons daily on the same dates as the average capacity of all other natural -gasoline plants increased from 22,200 gallons to 30,300 gallons . Owing to the elimination of small , obsolescent plants in Illinois , Oklahoma , and Pennsylvania , these States experienced the greatest reductions in numbers of plants in 1946 and 1947. In Oklahoma and Texas , several consolidations of two or more plants into a single operating unit were reported . Louisiana and Mississippi were the only States in which the number of plants increased , but daily capacity to produce light products was larger in eleven States on January 1 , 1948, than two years earlier . Added facilities in California and Texas accounted for 41 and 36 percent , respectively, of the national gain in capacity .

Sep 1, 1948

By E. Chin

Although Japan is a major producer of crude steel, it is poor in industrial raw materials. This Bureau of fines report describes Japan's raw material needs for chromium, cobalt, manganese, nickel, and tungsten to produce ferroalloys and alloy steels. Japanese imports of these ores or metals by quantity and source are given for 1972-81, inclusive, to indicate (1) the changes in the consumption and supply pattern, and (2) the degree of Japan's dependence on foreign sources. This report also describes measures implemented by Japan to reduce the risk- of supply interruption, and discusses the possible implications of supply shortages.

Jan 1, 1983

By J. E. Shelton

Flotation tests are described on samples of two lowgrade nickeliferous ores of Oregon and Washington. The sample from the Congress mine, Ferry County, Wash., contained 1.2 percent Ni, occurring chiefly as millerite. The sample from the Shamrock mine, Jackson County, Oreg., contained 2.20 percent Ni and 0.78 percent Cu occurring chiefly as pentlandite, nickeliferous pyrrhotite, and chalcopyrite. The millerite in the Congress ore was concentrated by flotatioin with aulfydric collectors in a series of locked tests to recover 73 percent of the nickel as a 7 percent bulk concentrate. By successively regrinding and floating the bulk concentrate, it was further concentrated to 12.4 percent Ni at a recovery of 59 percent and 21.8 percent Ni at a recovery of 50 percent. Attempts at selective concentration of the copper-nickel Shamrock ore were only partly successful because of the intimate association of pentlandite and chalcopyrite. The nickel concentrate, which contained 86 percent of the nickel, had an analysis of 4.42 percent Ni and 1.03 percent Cu. The copper concentrate had an analysis of 18.8 percent Cu and 1.96 percent Ni and contained 48.5 percent of the copper. A bulk sulfide concentrate contained 92 percent of the copper and 01 per¬cent of the nickel and had an analysis of 4.17 percent Ni and 1.63 percent Cu.

Jan 1, 1956

By E. P. Youngman

Before the World War the use of zirconium and its compounds was largely experimental and confined almost wholly to Germany and Austria . Occasionally small lots of zirconium ore had been produced in the United States ( 1,000 pounds in 1869 , 26 tons in 1883 , and 3,000 pounds in 1903 ) and used (with monazite ) in the manufacture of various lighting devices , especially incandescent gas mantles ; but it was not until 1906 that the discovery of the natural zirconium oxide in large quantities near Sao Paulo , Brazil , first gave promise that a zirconium industry eventually might be developed . Edward Rietz , who worked the Brazilian deposits , interested German chemists in extending the use of zirconium , and by 1911 trade journals were listing German firms as manufacturers of compounds or products derived therefrom . For a time zirconia was one of the various oxides used in the Nernst lamp . It was used also for crucibles and hearths as refractory material ; in the manufacture of chemical utensils ; in enamels ; in the place of bismuth subnitrate for defining Röntgenray pictures of the stomach ; as a pigment ; in medicine ; and in a number of other ways . The Germans were credited also with producing a remarkable zirconium steel , which , it was claimed , was much superior to other alloy steels . During the World War the United States Government investigated the possibilities of zirconium , as well as those of other steel -hardening elements , and a large automobile manufacturer actually purchased a substantial quantity of ore with the purpose of employing zirconium in automobile steels . Immediately after the armistice the Government ceased its investigations ; but despite the difficulties experienced by various investigators in reaching concordant results , interest in the use of zirconium as a steel -hardening agent , as well as in other uses of the element and its compounds , continued . In 1918 the Foote Mineral Co. , which had been interested in zirconium for several years , was exploiting the deposit in Brazil formerly worked by the Germans and was supplying zirconia in the form of ore , brick , and cement for refractory and other purposes . About the same time the Electro Metallurgical Co. , which before the entrance of the United States into the war was experimenting with zirconium alloys , supplied in tonnage quantities the demand for these alloys . In 1919 it was reported that American manufacturers , after several years of research, were producing in commercial quantities pure zirconium oxide , which was finding a place in the manufacture of small refractory articles , scorifying dishes , crucibles , tubes , and one- piece furnace linings . In 1920 the lowering of the price of zirconium metal powder ( because of improved metallurgical methods ) promised the production of the metal on a semicommercial scale . In 1924 the Titanium Alloy Manufacturing Co. introduced a new opacifying agent , " Opax , " made from zircon . A year or two later some of the large pottery manufacturers became interested in the use of zirconium oxide as an opacifying agent , the increased production of titanium pigments having resulted in the production of zirconium as a by-product at a price that could compete with tin oxide . In 1928 it was reported that the industrial use of zirconium oxide was increasing steadily in the manufacture of brick , crucibles , and other refractory products , such as high- temperature cements . However , the reluctance of producers to install additional and more suitable

Jun 1, 1931

By Lloyd Williams

1. This investigation shows that the Poplar Creek is the most important bed in Scott County from a production standpoint. Although the Poplar Creek bed contains the largest reserve, the Big Mary has a larger recoverable reserve. Estimates of reserves also have been made for the Pewee, Red Ash, Windrock, Upper Pioneer, Jellico, and White Oak beds. 2. Known measured and indicated reserves of coal, based on a minimum bed thickness of 14 inches and on 1,800 short tons per acre-foot of coal in place, are estimated to be 143 million tons as of January 1, 1954. Of this total, 74 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1956

This report on the Venezuelan coal industry is the seventh in a series of studies on coal exporting countries requested by the House Appropriations Committee, The committee asked that the basic differences in mining costs for U.S, and foreign mines be identified, especially those costs incurred in complying with health, safety, and environmental regulations.1 Basic costs in extracting raw coal are analyzed in this report for surface operations, This report also provides a limited analysis of the relative market competitiveness of selected Venezuelan and U,S. steam coal mines in three electric utility markets: New England and the east coast of Florida in the United States, and western Europe. Although some Venezuelan coal has coking characteristics, all coal-producing regions of Venezuela sell coal in steam markets.

Jan 1, 1994

By R. D. Leitch

The work of the United States Bureau of Mines on stream pollution3 by coal-mine drainage has included a study of seasonal variations in acidity and volume of several streams in Pennsylvania. The acidity of these streams has been determined during the two or three years prior to 1930 and the results may be considered to represent "normal" low water conditions. The summer of 1930, however, was unusually dry and represents what may be termed "extreme" low water conditions on these streams. This report is a comparison of the results obtained for extreme low water of 1930 and for other years. The streams investigated were Buffalo Creek in Somerset County, Indian Creek (lower 5 miles) in Westmoreland County, Little Toby Creek in Elk and Jefferson Counties, Daguscahonda Run in Elk County and West Creek in Elk and Cameron Counties. These will be treated separately in the order given. Most of the descriptive matter and physical data pertinent to the streams and drainage basins are taken from published reports of the Pennsylvania State Water Supply Commission, 1917.4

Jan 1, 1931

By Heine Kenworthy

"INTRODUCTION In 1930 the Shenandoah-Dives Mining Co. near Silverton, Colo., put into operation a newly erected, 300-ton selective flotation plant to mill complex ores from its nearby mine. The operation was a steady producer and was enlarged to treat 600 to 800 tons a day. In 1942 the company opened and started milling an area in the mine containing semioxidized ore. The valuable mineral content of this ore was considerably higher than in, the straight sulfide ore previously handled alone. The mixture of clean sulfide and semi-oxidized ore was difficult to treat; consequently, tailing losses, especially with respect to lead, were high. A few years later, in order to study the possibilities of obtaining higher recoveries by a modification of the mill flow sheet, a 1,200-pound sample of mill, feed, taken over a period of several days by the company, was submitted to the Mississippi Valley Experiment Sta¬tion for testing-. Although this sample proved to contain more than twice as much lead as the average yearly mill feed, the same problem of recovering the oxidized values was present.A résumé of the ore-dressing treatment used in the Shenandoah-Dives mill follows. After crushing, the ore passes through a ball mill, the minus 5-mesh discharge of which is distributed to three tables. A finished lead concentrate is made on the tables, and the table tailing goes to the classifier which is in closed circuit with the ball mill. The classifier overflow is treated -by flotation to obtain a bulk sulfide concentrate at a relatively coarse size. The bulk concentrate is thickened and reground to about 95 percent minus 325-mesh before flotation treatment to separate a lead-copper and a zinc concentrate. A typical monthly average showed that the table concentrate contained about 45 percent lead, 1 percent copper, 4 percent zinc, 12 ounces of gold, and 40 ounces of silver; that the lead flotation concentrate contained '35 percent load, 6 percent copper, 7 percent zinc, 3.5 ounces of gold, and 50 ounces of silver; and that the zinc flotation concentrate contained 2 percent lead, 0.5 percent copper, 60 percent zinc, 0.15 ounces of gold, and 4 ounces of silver. Recoveries in salable products were roughly b5 percent of the lead, 70 percent of the copper, 45 percent of the zinc, 85 percent of the gold, and b5 percent of the silver."

May 1, 1948

1.0 SCOPE AND REGULATIONS 1.1 This specification covers the minimum requirements for material handling and associated equipment including design and materials. 1.2 This specification requires compliance with all federal, state, local laws and regulations which may be applicable including the Occupational Safety and Health Act, Construction Safety Act as well as rules, regulations and standards of the Secretary of Labor.

Jan 1, 1979

By R. C. Corey

Anticipating the need for convenient, economical, and safe means for disposing of combustible wastes contaminated with low-level activity, in connection with private and institutional uses of radioisotopes, the Atomic Energy Commission (AEC) has provided the Bureau of Mines with funds to develop an incinerator for this purpose. A prototype incinerator, designated hereafter as BOMAEC-30, was designed, constructed, and tested, based on fundamental and applied research investigations of the combustion characteristics of rubbish and sawdust, which will comprise the bulk of contaminated wastes. No radioisotopes were used in the tests; the objective was to remove as much particulate matter from the products of combustion as possible. The prototype unit was designed to burn 30 pounds per hour, using 100 percent over fire air admitted tangentially in an all-metal, cylindrical combustion chamber. The gas-cleaning system consisted of special fabric bags and absolute filters.

Jan 1, 1962

By R. HOLROYD

The Ludwigshafen and Oppau plants are largely independent I. G. factories situated some 23 miles apart on the west bank of the Rhine facing lannheim. The former factory is a general organic chemical works specializing in dyes, dye intermediates, plastics and synthetic rubber,. while the latter is a heavy organic chemical factory producing ammonia, methanol, higher alcohols and their derivatives. Before the war much of the I. G. research and development work was carried out at Ludwigs- hafen; in particular the high pressure research section directed by Dr. Mathias Pier played a very active part in all hydrogenation developments. Apart from the possibility that a full scale hydrogenation or Fischer Tropsch plant had been erected at Ludwigshafen/Oppau during the war, the main objectives of an oil team investigation were: - (a) To obtain from Dr. Pier and his staff an advance general picture of German fuel production processes. (b) To study the fuel developments still in the research and pilot plant stage. (c) To examine any new developments in hydrogen or synthesis gas manufacture. (d) To look for new processes for production of high anti-knock fuel constituents and for new fuel additives. (e) To investigate new chemical syntheses based on raw materials obtainable from oil. The Ludwigshafen and Oppau factories were first visited by the large team listed in Appendix A during the period 25-31st March. The investigation revealed that no large plant for synthetic fuels or lubricants had been operated at this target. All the important members of the Fuel Research Section staff had been evacuated to Heidelberg and information on the work of this department was therefore limited to that contained in seized documents, the greater part of which have still to be examined in detail. Valuable information on synthesis gas production from hydrocarbon gases was obtained as well as interesting data on a num- ber of chemical syntheses. Two members of the above team Holroyd and Faragher accompan- ied by Major Tilley (interrogator) went on to Heidelberg, contacted Dr. Pier and the chief members of his staff on April 1st and obtained from them the hydrogenation information given later in the body of the report. Later, after visiting Leuna, Holroyd, Faragher and Ellis paid a second visit to Heidelberg and to Ludwigshafen/Oppau on 27th-30th May to check a number of details, particularly with respect to hydrogenation costs, and to obtain information on the pressure.conversion of water gas to hydrogen and on the manufacture of Wickel pressure vessels.

Aug 1, 1943

By E. P. Youngman

In the Unfederated Malay States, with the exception of Johore, the rights of suzerainty, protection, and administration were transferred by giam to the British Government in 1909. In the States of Kelantan, Trengganu, Kedah, and Perlis, the rulers are assisted by State Councils and by British advisers appointed by the British Government.3 With respect to Johore, the largest, richest, and most highly organized of the Malay States not in the Federation, the treaty of December 11, 1885, with Great Britain, defined the relations of the State to the British Govern- ment and allowed the Maharaja to assume the title of "Sultan"; an amendment to this treaty (May 12, 1914) provided that the Sultan should be advised by a British officer, the General Adviser. ...... The political organization of the States is reflected in the mining legis- lation, Johore being the only one having a comprehensive code. The mining enactments now in force, according to the High Commissioner for the Malay States, are as follows:

Jun 1, 1932

By Roy E. Williams

1. The major sources of heavy metal ions in wastewaters of the Coeur d'Alene Mining District are effluents from metallurgical processing plants. Effluents from mine operations provide a secondary source for heavy metal ions. Based on data analyzed by the Federal Water Quality Administration, mercury and arsenic are escaping from some mill waste ponds, but they are in the suspended phase. 2. Metallurgical process effluents are combined with mine waste effluents in tailings ponds, consequently, the quality of the tailings pond decant water is highly degraded. The major effect of combining metallurgical process effluents with mill wastes is a drastic change of pH in the tailings pond. This chance may be an increase or a decrease depending on the metallurgical process. The effluent from an electrolytic antimony plant drastically increases the pH in the tailings pond permitting the removal in solution of antimony via the pond decant system. The addition of low pH effluents to the tailings ponds results in a net decrease in pH which makes lead, zinc, cadmium, and copper more soluble, thereby permitting their removal from the pond via the decant system.

Jan 1, 2011

By BUREAU OF MINES

PLATINUM

Feb 1, 1922

By A. T. Harris

Ground quartzite, known in the industry as amorphous silica, is produced from a quartzite deposit near Honey Brook, Pa., by George F. Pettinos, Inc., of Bala-Cynwyd, Pa. The quartzite is mined by the open pit method and processed in a mill at the mine. The operation regularly produces five standard grades of sand and one grade of crushed stone; however, the company accepts special orders and will produce material to meet the customer's specifications. Beneficiation (chiefly crushing and screening) is controlled by laboratory screen tests on samples taken during preparation of the sand. The chief uses of the sand are for foundry operations, furnace lining, concrete aggregate, and Other specialized uses. The quartzite in this deposit is of uniform composition and does not require control by chemical analysis. However, for special purposes, analysis will be furnished.

Jan 1, 1965

By A. L. Engel

This report is a compilation of results of brief preliminary tests on sulfide ores that contained gold and silver and, in some cases base metals. It is a companion paper to a recent similar report on oxide ores. Simple treatment methods employing the least possible equipment sometimes produce satisfactory results on marginal ores and in small-scale operations. Investigations of typical ores from newly discovered or recently explored mining districts have been made in continuation of a long-established part of the hydrometallurgical and ore-dressing program of the Reno station, Bureau of Mines. The purpose of such investigations is to encourage the search for and development of mineral resources and particularly to assist in the economical exploitation of low-grade and marginal ores as well as the conservation and recovery .of values in products that were discarded from former operations because of inability to treat them profitably. Several of these investigations have been limited to preliminary tests of samples from prospecting operations, whereas same involved samples of old dumps or tailings piles. The test work in these cases was not extensive enough to warrant publication as individual reports, but is of considerable interest inasmuch as it indicates the possibilities as well as the limitations of treating the respective materials. The samples were representative of the districts from which they wore obtained, so this information should be helpful in the future development of these districts.

Jan 1, 1951

By Richard V. Ageton, Harry E. Tufft, E. A. Holbrook

When an underground excavation is made, the rock surrounding the sides and top of the opening is deprived of its natural support and tends to fall. Whenever caving takes place, the time and extent of the caving depend on the character and condition of the rock. In strong homogenous rock, such as solid granite, even a large chamber may stand indefinitely, whereas a soft material, such as clay or a loose material like unconsolidated sand, falls immediately if not supported. Weaknesses in the rocks induced by structural features, such as joints, :fissures, bedding and cleavage planes, and fractures produced by blasting, will cause the falling of insecure blocks or slabs unless means are provided to support these in place. In an unsupported mine opening, as a tunnel, the first slight settling or adjusting movement of the rocks (the "initial creep" or "set") is caused by the great weight of overlying material pressing down the rock masses above and around the roof and sides of the opening until they key together in roughly the form of an arch. The rock, after it has adjusted itself to this shape, becomes. selfsupporting. Timbering is necessa.ry in all mining only to support, therefore, those comparatively small blocks or pieces of rock which tend to loosen from the top and sides of the opening during or after the formation 'of the natural rock arch, and which lie between this natural rock arch and the opening. This statement, of course, has its limitations. For example; a layer of strong rock, like limestone, may act as a beam; then only the material under the limestone will need support. Timbering is not, as is commonly supposed by the layman, used to supp!ort the huge mass of rock between the back (roof) of an underground opening and the surface. It would be impossible to place enough timbers in a:ny underground opening to support such a mass. This fact is not'·perceived by all miners.

Jan 1, 1923