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By J. E. Tiffany, Z. C. Gaugler

This supplement has been prepared to furnish information on amendments to the regulations that were approved by acting secretary of the Interior on June 24, 1946, while this report was in the press. Page 14, item 2, and page 20, item 4, have been amended by the addition of the following footnote: "Pending the development of a satisfactory multiple-shot permissible blasting unit, a blasting unit of Type II, Class A, covered by Federal Specification WB 411, December 31, 1941 (with or without Amendment 2, June 16, 1945), may be used until Decem- ber 31, 1947. Should a satisfactory multiple-shot permissible unit be made available prior to that date, this interim approval may be terminated." Page 14, footnote / has been amended to read as follows: "The use of charges over 1-1/2 pounds and not exceeding 3 pounds is approved pending further investigation. The approval, which may be withdrawn at any time, expires December 31, 1947, unless renewed. For charges over 1-1/2 pounds, the following additional requirements must be observed: (1) Shot holes must be 6 feet or greater in length. (2) Explosives must be charged in a continuous train with no cartridges deliberately deformed or crushed, with all car- tridges in contact with each other, and with the end cartridges touching the rear of the hole and the stemming, respectively. (3) The permissible explosive must be one showing toxic gas omission that will place it in either Class A or Class B."

Jan 1, 1947

By Robert C. Sutter

In 1958, it became obvious to some of us in the solution mining business that there were certain problems in connection with our sodium chloride brining operations which were industry- wide. These were the types of problems which, while they were important to the safe and economical operation of our salt brining operations, were not such that their solutions would give an individual company a great competitive advantage over his competitor; and since they involve the safe and efficient mining of a natural resource, it was obvious that the answers would, in any event, be shared industry-wide. Since we were dealing with underground solution mining and, consequently, unseen and remotely controlled operations, the problems are formidable and the solutions difficult. While all of us were doing work to improve our operations, none of us could justify the expenditures necessary for basic research in these areas. Consequently, the idea was conceived of research sponsored by many companies with the same problems. In 1960, 11 companies entered into a' formal agreement to jointly support research on a specific problem of sodium chloride solution mining. The project to be undertaken was the development of a method for measuring the size and extent of underground solution cavities in sedimentary salt beds. It was agreed that all research was to be performed by independent research organizations. A part-time consultant or administrator was retained to administer the research contracts and to provide technical advice.

Jan 1, 1966

By Richard E. Hucko

The Coal Preparation Division of the Pittsburgh Mining Technology Center conducted an investigation to assess and compare the pyritic sulfur reduction potential of coal-pyrite flotation and high-gradient magnetic separation (HGMS). Tests were run on three coals--an Upper Freeport bed coal, a Lower Kittanning bed coal, and a Pittsburgh bed coal--to establish grade- recovery relationships characteristic of both processes. Representative portions of each coal sample were crushed to two top sizes--nominal minus 35 mesh (0.5 mm) and nominal minus 100 mesh (0.149 mm)--and subjected to conventional froth flotation. The froth product was then beneficiated by coal-pyrite flotation or HCMS to provide a direct technical comparison of the two processes. At minus 35 mesh (0.5 mm), the size normally employed for coal flotation, both coal-pyrite flotation and HGMS effectively separated pyrite from coal, and the performance of the two processes was essentially the same. At a size of minus 100 mesh (0.149 mm) , however, the performance of HGMS exceeded that of coal- pyrite flotation. The separations effected by HGMS were more efficient at minus 100 mesh (0.149 mm) than at minus 35 mesh (0.5 mm). On the other hand, it was concluded that either the effectiveness of coal-pyrite flotation decreases with diminishing top size, or the process has not been optimized to treat material finer than 35 mesh (0.5 mm).

Jan 1, 1981

By L. E. Geyer, W. W. Adams, M. G. Parry

"More than 73 million pounds of rock dust were used by the bituminous-coal-mining companies in the United States during 1930 to present or limit loss of life and destruction of property from explosions of gas and coal dust in underground mining operations, according to statistics compiled by the United States Bureau of Mines from reports furnished by mine operators. The mines using rock dust produced 65. 691, 753 tons of coal during the year, more than 30 percent of the total production of bituminous coal from underground mines in the United States that year. Although only 382 out of a total of 5,629 active underground bituminous mines applied rock dust to underground working as a precaution against explosions, they were chiefly the larger producing mines, employing 25.4 percent of all of the underground bitumious mine workers in the United States and accounting for 27.4 percent of the total number of man-hours worked underground at bituminous mines.a summary of the reports for the 382 mines using rock dust showed a total production of 96,691,755 tons of bituminous coal, 89,503 men employed underground, and 129,718,965 man-hours worked by the underground employees. (See tables 1 and 2.) These mines averaged 8.76 pounds of rock dust per ton of coal shown by reports from 385 mines using rock dust in 1932 (See table 3.)"

Nov 1, 1935

Overview of Presentation Why Enter Agreements with First Nations Making it Win-Win ?The Principles The Process Making the Process Work Resource Agmts Defined Resource Agreements are legally binding agreements between a resource company and the First Nation(s) whose Aboriginal or Treaty rights may be impacted by the activities of the proposed project

May 1, 2009

By Weijia Guo

With the exploitation of coal resources, a large area of land had been affected by surface subsidence, causing conflicts between man and land to become more conspicuous by the day, affecting the life of general public, and constraining further development of the land. This paper predicts the subsidence areas according to the 10-year mining plan of the Jibei mining district as an example. A plan of environmental management was developed based on sciences and practical economics.

Jan 1, 2006

By Kefton H. Teague

History of the feldspar industry in the United States has been summarized by DuBois (I)*. The earliest production of feldspar in the United States is reported to have been from Mitchell County, North Carolina, about 1744, with the product shipped to England, In about 1825 several pegmatites were worked to a limited extent in Connecticut, with the production shipped to England. The first feldspar grinding facility was constructed about 1850 in Connecticut, with chaser mills used. Feldspar has been produced continuously in the United States since about 1870. Feldspar is produced from the following states: North Carolina, California, Georgia, Connecticut, South Carolina, South Dakota, Kansas, Oklahoma, Virginia, Arizona, and Wyoming. Total United States production for 1969 will amount to approximately 900,000 tons. The most current published figures for world production is 1966, at which time 2,165,000 tons was produced. It is estimated that world production of feldspar for 1969 will amount to 2,410,000 tons. Historically, feldspar has been produced by hand sorting and hand cobbing of coarse block feldspar obtained from the intermediate and wall zones of zoned pegmatites. In the United States the reserve of known block feldspar, recoverable by hand sorting is nearing depletion. More emphasis is now placed on feldspar sources contained in finer grained rocks, especially coarse granites or fine-grained pegmatite and beach, dune, and river sands from which the feldspar is obtained by beneficiation.

Jan 1, 1970

By M. F. Dibble

The technology available for mining of underwater mineral resources such as placers and phosphorite, typically occurring with variable amounts of overburden, has remained largely unchanged for decades. The traditional bucket ladder dredge with maximum digging depth of 48 m and monthly capacities about 500,000 m3 still reins as the only heavy duty mining system capable of working the tough materials characteristic of heavy metal placers. Attempts at adapting the bucket wheel cutter-suction dredge to these severe conditions have not yet been successful except in moving small volumes from shallow depths. High capital cost (20-30 million U.S. dollars), high cost of overburden removable, and turbidity generation for the bucket ladder are often significant negative factors in mining operations where this system remains the only viable alternative. The Japanese continue to advance the technology of their submersible dredge pump system powered by specially adapted, direct drive electric motors. Present systems are designed primarily for working surficial deposits of aggregate to depths as great as 90 meters, the pump suspended by cable from a surface vessel with an eductor pipe leading from the pump to the vessel. Such a system may prove adaptable to a variety of surficial deposits including phosphorite, shell and heavy minerals in addition to aggregate. However promising for the exploitation of surficial deposits, little advantage can be expected for the deeper buried and more difficult deposits.

Jan 1, 1986

By David J. Lowell

The gold content of porphyry copper deposits ranges from less than 0.05 g/t to more than I g/t ((0.0017 to 0.035 oz per st) and the average is about 0.05 g/t (0.0017 oz per st) gold. Perhaps the highest grade mineralization found near a porphyry cop¬per deposit is the Ok Tedi Gold Cap ore body whose grade falls in the 2 to 3 g/t (0.07 to 0.1 oz per st) range. It is difficult to define a gold-rich por¬phyry copper deposit. All porphyry copper ore bodies contain some gold, but there seems to be a fairly sharp break in the gold content at about 0.1 g/t (0.003 oz per st) gold. There is also a problem in identifying dis¬seminated gold deposits that may have an indirect relationship to porphyry copper systems. This relationship is clear cut in deposits such as the Ok Tedi Gold Cap, the El Hueso deposit, the Fortitude and West de¬posits at Battle Mountain, NV, and the Sur¬prise deposit at Ely, NV. There are many other bulk disseminated, epithermal-type gold deposits - McCoy, NV, for example - that might be related to a porphyry system but where this relationship is remains very uncertain. In such places as the Goldfields and Tonapah district in Ne¬vada and in the El Indio, Chile district, there may be a vertically stacked ore deposit rela¬tionship between near surface epithermal deposits and disseminated molybdenite and chalcopyrite enargite mineralization at depth that may represent a deep porphyry system. This, however, has not been positively demonstrated. Most of the bulk epithermal gold deposits are probably not related to porphyry copper systems. Exceptions would probably be Ok Tedi, El Indio, El Hueso, Battle Mountain, and Lepanto where vertical or lateral zoning relationships are more apparent. This author believes that porphyry copper systems are related to a relatively unique type of intrusion that is probably distinct from, for example, the McCoy intrusivebody. For that reason, deposits such as McCoy, Chimney Creek, and the like will not be included in the definition of gold-rich por¬phyry copper deposits for this article. The interpretation of the origin of several of the deposits previously mentioned are subject to an unusual amount of contro¬versy. For example, geologists seem to be equally divided about the presence of a porphyry copper deposit below the El Indio deposit. Geologic setting Continental vs. island arc Several geologists have speculated that the gold-rich, moly-poor, porphyries are

Jan 1, 1989

By George S. Rice

"""To prevent the propagation of mine explosions, the Bureau of Mines, Department of Commerce, recommends rock-dusting all coal mines, except anthracite mines, in every part, whether in damp or dry condition. It also recom¬mends that rock-dust barriers be used to sectionalize the mine as additional defense; but these should not be regarded as a substitute for generalized rock-dusting."" (Mine safety decision, No. 5, April 7, 1927.)The purposes of this circular are to present concisely the requirements for effective rock-dusting of coal mines in order to prevent propagation of mine explosions, and to point out the principal related facts on explosibility of coal dusts and mixed coal-mine dusts, as determined by extensive testing in the Experimental Mine of the Bureau of Mines. study of these principal facts on coal-dust explosibility in conjunction with the recommendations for rock-dusting, should help to make clear to mine operators and others concerned the necessity for systematic rock-dusting in all coal mines except anthracite mines, and the futility of inadequate or sporadic rock dusting.The descriptions of nearly 1000 explosion tests in the Experimental Mine are available in a forth-coming bulletin2 and in earlier publications.3For detailed specifications as to the kind of rock-dust, amount to use, where to be applied, and method of sampling and testing, the reader is referred to Bureau of Mines Serial 26064, and American Engineering Standard Committee ""Recommended American Practice for Rock-Dusting Coal Mines"" quoted in Bureau of Mines Information Circular No. 60305.Summary of Specifications for Rock-Dusting1. Mines to be rock-dustedAll coal mines, except anthracite mines, should be rock-dusted.2. Extent of rock-dustingAll open accessible parts of a coal mine should be rock-dusted, including slopes, entries, cross,-cuts, and rooms, headings and pillar workings to within at least 50 feet of the face.3 Amount of rock-dustingAfter cleaning up the coal dust as thoroughly as practicable, sufficient rock-dust should be used to have the mixture of remaining coal-dust plus the rock-dust in any zone contain 65 per cent or more of inert or noncombustible matter. First dusting may require 3 pounds to 5 pounds per linear foot of passageway.4. When to rock-dust In any zone or section (made by dividing the mine for rock-dusting purposes) when the incombustible content falls to 55 per cent, that section should be re-rock-dusted so as to bring the incombustible content well above 65 per cent."

Jun 1, 1927

By L. C. IlsLey

Many accidents rightly classifiable as electrically caused are not so classified for the reason that in numerous accidents the part that electricity played in causing the fatality is only suspected. For instance, a workman might receive a shock that would cause him to lose his balance and fall beneath a trip of cars; if no one saw the first part of the accident, the cause undoubtedly would be charged to "haulage." This paper covers a brief study of fatal and nonfatal electrical accidents. The first usually result from direct contact with the electrical circuit or electrical apparatus; the second more often are the result of arcing or flashing due to handling defective apparatus or making repairs on "live" equipment or circuits. It is hoped that helpful suggestions may be offered for minimizing accidents of these two classes.

Jan 1, 1938

By Peter Zhang, Daniel Su, Bo Kim, Berk Tulu

This paper summarizes significant findings from the ongoing NIOSH Gas Well Stability research over the past decade; in particular, the important ground control engineering considerations. Longwall-induced surface and subsurface deformations may induce gas well casing deformations and stresses, depending on a few parameters such as overburden depth, overburden geology, topographic relief, strata dip, gas well setback distance, and a gas well casing cementing alternative. Overburden depth to the mining seam is one of the most influential factors; shallow overburden depth induces large horizontal displacement and resulting casing deformation and stress, while deep overburden depth induces large longwall-induced vertical pressure. Overburden geology is another important factor affecting the longwall- induced casing deformations and stresses; the large contrast of bending stiffness at the soft-to-hard rock interfaces tends to induce large casing deformations and stresses. Large surface topographic relief and the presence of soft-to-hard rock interfaces below the stream valley bottoms may shift longwall-induced subsurface gas well casing deformations closer to the surface, thus having less impact on underground. mining operations. Strata dip magnifies longwall-induced deformations by 20% per degree of strata dip for down dip longwall excavations. The gas well setback distance is also a critical geometric parameter; the effect of longwall-induced deformation decreases exponentially as the setback distance increases. Longwall-induced casing deformation and stress will be mitigated or totally uncoupled for uncemented production casing.

Jun 25, 2024

By Attie J. Goosen, William L. Spiteri

Although the physical characteristics of ANFO made from porous prilled ammonium nitrate (PPAN) have been altered by the addition of crystal modifiers, the optimisation of prilling processes and the admixture of waterproofing agents, the sensitivity of this explosive has not been modified on a commercial scale in the 40 years since its accidental discovery.

Jan 1, 1995

By R H. Stevenson

This paper deals with a new variation of the cast blasting technique, where-in the object is to cast the economic deposit out front under the overburden, while avoiding dilution from the floor material. To date, the technique has been successfully applied at two cement quarries in Iowa and at a granite quarry in Minnesota.

Jan 1, 1991

By R. G. Weavind

ONE of the most important fields of investigation at the Diamond Research Laboratory in Johannesburg is concerned with improvements in metallurgical practices for the diamond mining companies, with particular reference to increased recoveries of the smaller industrial stones. Considerable work has been done on the possible application of flotation processes to the diamond industry.

Jan 7, 1951

Escondida is a state-of-the-art copper mining operation. It is the major copper project of the 1990s and is the largest new investment in the industry - a US$823 million project. It accounts for about six per cent of Chile's total exports, making Escondida the largest private exporting company in Chile.

Jan 1, 1992

By J. B. Mitchell

The intelligent selection of comminution systems for industrial minerals requires a broad background of comminution experience. At the same time a thorough knowledge of the specific mineral occurrence, the applicable process and the product end use is required. To illustrate the different ways to process potash ores three flow sheets have been selected for presentation.

Jan 1, 1970

By C. Bohdanowicz

The most important decline in drilling activities during the past three years was in the Boryslaw-Tustanowice-Mraznica fields and at Bitkow in Eastern Poland. A small drilling increase in some fields of the Jaslo and Drohobycz districts, notably Wankowa, Ropienka and Rypne, cannot compensate in new production for the decline in the large fields.

Jan 1, 1934

By Alex Jankovic

The paper point out the high capacity processing of a hard, fine grained silica rich magnetite ore with several circuit operations was carried out to assess the energy efficiency, operating cost and project economics expressed through NPV. The result of the study autogeneuss grinding technologíes offers significant benefits over the conventional grinding circuits options.

Sep 21, 2013

By Claude Cunningham

Late in 1982 a fire began in the shallow, abandoned workings of the Uitkyk Colliery near Witbank, South Africa. Urgent measures had to be taken to quench the fire, before the surface caving it caused could put an important railroad connection out of action. This paper outlines the way in which the job was tackled.

Jan 1, 1984