Search Documents

By A. C. Noble, D. E. Ranta

Orebodies with intricate three- dimensional shapes (such as porphyry molybdenum deposits) are difficult to model using geostatistics or other computer- assisted methods. 'The strong trends in their spatial grade distributions occur as mathematically complex shapes and prevent the customary assumption of local stationarity that is required for accurate ore reserve estimation. "Zoned Kriging", a new method developed by AMAX, solves this problem directly by using the geologist's interpretation of the ore zones as a parameter in the kriging equations. The geological basis and methods used in the Climax ore zoning technique are reviewed and discussed relative to their application in zoned geostatistical modeling. The Zoned Kriging technique is described and demonstrated using data typical of mineral de- posits.

Jan 1, 1984

By Alfred H. Bell, George V. Cohee

In 1939 Illinois produced 94,302,000 bbl. of oil—almost three times the amount of oil produced at the peak in 1908, when development in the southeastern Illinois field was at its height (Fig. I). It represents nearly a fourfold increase over the 24,075,000 bbl. produced in 1938 (Table 6). This rapid increase in oil production in Illinois is largely due to development in the Salem and Louden fields (Table I). During 1939 daily production for the state increased from 135,000 to 332,572 bbl. A notable increase in production for 1940 is expected as a result of the drilling of the Devonian limestone in the Salem and Centralia fields,

Jan 1, 1940

By Alfred H. Bell, George V. Cohee

In 1939 Illinois produced 94,302,000 bbl. of oil—almost three times the amount of oil produced at the peak in 1908, when development in the southeastern Illinois field was at its height (Fig. I). It represents nearly a fourfold increase over the 24,075,000 bbl. produced in 1938 (Table 6). This rapid increase in oil production in Illinois is largely due to development in the Salem and Louden fields (Table I). During 1939 daily production for the state increased from 135,000 to 332,572 bbl. A notable increase in production for 1940 is expected as a result of the drilling of the Devonian limestone in the Salem and Centralia fields,

Jan 1, 1940

By L. A. Jr. Norman

ANOTHER chapter in the history of Mother Lode mining is being written by operations in the Old Eureka mine near Sutter Creek, Amador County, California. During a two-year period (1938-1939), 85,517 tons of ore averaging 0.62 oz. gold per ton were mined and milled, as compared to the production of approximately 210,000 tons of 0.315-oz. gold ore during the preceding seven years. This is a repetition of mining history in the Mother Lode, where a period of prosperity has followed a long period of lean production. The location of this new ore in the hitherto unproductive hanging-wall greenstones and its mining and geological developments are most interesting.

Jan 1, 1939

By O. A. E. Jackson

Pebble milling has been practiced in the reduction works of South Africa gold mines for well over 50 years. Originally flint pebbles were imported from Denmark to grind stamp-mill amalgamation- process tailing, which contained a good deal of extractable gold, but local operators soon found that large pieces of ore could be used for the same purpose. The ore is a hard, tough conglomerate in which quartz pebbles are cemented together by a matrix of redeposited silica interspersed with pyrite crystals. The gold, rarely visible, occurs as fine particles mostly segregated at the interface of the pebble and matrix, although a small fraction occurs within the pyrite crystals. There is seldom any gold in the pebbles themselves.

Jan 11, 1959

By L. G. Huntley

Introduction IN View of the recent advance made in the knowledge of the nature and conditions accompanying the occurrence of oil and gas, and of the recent activity in drilling in Wyoming, Montana, and western Canada, a discussion of the probabilities of obtaining production in such a reservoir as the Dakota sand in general, and in particular districts, is thought by the author to be timely and likely to result in more intelligent operating in certain parts of the territory underlain by this sand. In Canada particularly it is thought that these general considerations have equal if not more significance in a consideration of the oil and gas possibilities of the formations than have the various local conditions.

Jan 6, 1915

AN UNUSUAL OPPORTUNITY FOR INSTITUTE MEMBERS to increase or complete their sets of the Transactions. In order to encourage the custom of members increasing each year the number of Volumes of the Transactions in their private libraries until the sets are complete, the Board of Directors has authorized the sale of Transactions previous to the year 1913 at the following greatly reduced rates. This offer is made effective for sales made only during the year 1914, and applies only to members in good standing, and to libraries. The reduced price automatically ceases to apply to any volume when the total number of such volume left in stock is reduced to fifty (50).

Jan 12, 1913

Very few data are available about production in this county. The amount mined was used locally, or shipped by river, until 1839 when the canal was completed to Dunnsburg. Only partial records for four years remain of canal shipments. Considerable coal was used locally by the iron works at Farrandsville for some years. Rail shipments started in 1861 and those shown are the estimated shipments of these mines as compared with the mines in other counties served by the Philadelphia and Erie Railroad, the total tonnages being given in the annual reports to the Auditor General. It is not likely that any coal used by the railroad is included in these figures. (Table 40.)

Jan 1, 1942

The Institute maintains for the use of members (and especially for the use of out-of-town members) a reading and writing room, where all usual office facilities are available, including telephone, telegraph, receipt, forwarding and care of mail and express packages, etc. A file of current magazines is also maintained in this room, and the Institute's staff will lend its best efforts to serving the members in connection therewith. The Institute also maintains for the use of its members free dressing rooms, library research department, etc. Attention is called to these facilities at the present time in the belief. that they may be especially useful to out-of-town members in connection with the Meeting.

Jan 5, 1918

By L. D. Jaffe, W. P. Clancy, D. C. Buffum

Many earlier workers have suggested that the temper brittleness of steel is associated with the presence of carbon or nitrogen. Nevertheless, no investigations on the effect of removal of these elements upon susceptibility to temper brittleness have been published. It was therefore decided to determine whether temper brittleness would develop in an iron alloy ...__, ing very little carbon and nitrogen. The alloy, in the form of a 10-lb ingot, was prepared by melting purified materials under . argon. Its composition, in per cent, was: This analysis, except for carbon content, is within the specified range for SAE 3140, which has been demonstrated by previous work at this laboratory2 to be markedly susceptible to

Jan 1, 1950

By William E. Ford, Edward Salisbury Dana

262. Parallel Grouping. - Connected with the subject of twin crystals is that of the parallel position of associated crystals of the same species, or of different species. Crystals of the same species occurring together are very commonly in parallel position. In this way large crystals, as of calcite, quartz, fluorite, are sometimes built up of smaller individuals grouped together with corresponding faces parallel. This parallel grouping is often seen in crystals as they lie on the supporting rock. On glancing the eye over a surface covered with crystals a reflection from one face will often be accompanied by reflections from the corresponding face in each of the other crystals, showing that the crystals are throughout similar in their positions.

Jan 1, 1922

By L. J. Cabri

The calculation of metallurgical balances for precious metals is very dependent on a precise mineralogical understanding of the distribution of each element. Determination whether the precious metals occur as dilute solid solutions in major minerals is not always easy because of the relatively high levels of detection (9200-500 ppm) of the precious metals by the most common methods of in-situ analysis (e.g. electron microprobe). Particle Induced X-ray Emission (PIXE) analysis of sulfides from Izok Lake, N.W.T., Canada and from the Hilton mine, Mount Isa, Australia with a proton beam (proton microprobe) confirms solid solution of Ag in chalcopyrite from both deposits. In addition, chalcopyrite and sphalerite from Izok Lake both contain indium.

Jan 1, 1984

Alan Stanley (Titanium Dioxide Analysis of Maclntyre Ore by Specific Gravity, P. 971) is currently head of the General Metallurgical Group of the National Lead Co. He has been with National Lead since 1946, after serving with the USAAF as a first lieutenant of engineers during World War II. A native New Yorker, he graduated from Virginia Polytechnic Institute in 1942 with a Bachelor of Science in Chemical Engineering. Since joining National Lead he has been a flotation supervisor, in the high tension pilot plant, and done sinter testing. He is an AIME member and presented one other paper before the Institute, Sintering Characteristics of Minus 65 and 20 Mesh Magnetite. Stanley plays the piano in his leisure moments.

Jan 1, 1952

By W. R. Marks

Computer-aided torsional analysis of grinding mill drives is defined and related to the mill design process. Equations of torsional dynamics are developed for general mechanical drives. Consideration is given three solution types - specifically the determination of undamped natural frequencies, the calculation of steady vibration amplitudes, and the prediction of transient torques during starting. Following a summary of the methods of calculating drive motor performance, the problem in making practical application of this theory are discussed. Experiences in both calculating and measuring the torsional loads on a large ball mill with dual synchronous motors are reviewed. Conclusions are drawn on the effectiveness of computer-aided torsional analysis for improving mill drive reliability.

Jan 1, 1984

By George B. Holderer

The relation between man-hours of labor and production may be correlated for any industry, and already it has been widely used in piecework studies. It is not in general use as yet for recording labor efficiency of an enterprise or an industry. An exception to this is the Cement Institute, which tabulates the man-hours used in each operation and thus gets the total man-hours per barrel of cement. The writer knows of one steel company that keeps a complete record of man-hours for every operation from mining the ore to finishing the product. No doubt many others find the information useful, and such a study could be of value to the mineral industries.

Jan 1, 1937

By Clarence O. Babcock

A simple robust rock bolt load gage was tested in the laboratory to define its characteristic behavior and to obtain a measure of its performance. The gage uses three vibrating wire sensors crimped 120 (2.09 rad) apart into the outer surface of a hollow cylindrical steel, tube. The resonant frequencies of the wires change as the gage is loaded. This change is read with a Creare meter developed for the Bureau of Mines on a previous contract to read borehole stress gage results. A statistical analysis of data obtained defines the variables influencing results. A U.S. patent (3,914,992) assigned by the author to the Dept. of the Interior was granted Oct. 28, 1975.

Jan 1, 1978

By L. Edeleanu

Crude petroleum is a mixture of various groups of hydrocarbons and some bodies containing oxygen or sulphur.

Jan 1, 1915

By H. A. Kuhn

The Pittsburgh coal field in Western Pennsylvania is conceded to be the most important in the world.

Jan 1, 1915

By J. E. Nelson, R. J. Bonnis

Recent completion of Cyprus Bagdad's $240-million modernization and expansion program has registered a 700% increase in ore production with only a 50% increase in labor. Elements of this remarkable achievement include the application of large-scale mining equipment as well as the selection of the latest in processing hardware. Most important, however, was the early recognition that Bagdad's labor personnel is its most important asset.

Jan 4, 1978

By David C. Russell

The Department of the Interior used to be a quiet, noncontroversial, almost boring agency. It, after all is the fifth oldest of the Departments, and as an old line Federal agency it has studiously performed its preservation and resource management functions in a caretaker mode--though some would say more "undertaker" than "caretaker"--locking up the body and soul of America piece-by-piece. Yes, quiet, serene. That is until Jim Watt showed up. And we have all seen that version of Mt. Vesuvius which resulted--only it was the environmentalists who blew their tops. Ronald Reagan chose Jim Watt as Secretary of this fine old agency to prove that one-third of our Nation's land and over a billion acres on the Outer Continental Shelf can work for this Nation. At the foundation of President Reagan's charge to Secretary Watt is a belief in the tenets of the free enterprise system, and in the individual freedoms upon which this country was founded. There are those who don't share this belief in democracy and free enterprise, and those who believe this 205 year experiment called the United States of America will fail. Nikita Krushchev said "we will bury you"--obviously he didn't agree with our system. An Italian sociologist, Franco Ferrorotti, said bureaucratic stagnation will kill capitalism. Certainly we have all felt the ravages of bloated bureaucracies. Perhaps one indicator in the United States is the Federal Register, that daily compilation of Government's largesse. In 1970, 20,000 pages of the Federal Register were published. A decade later, in 1980, that volume had quadrupled to 80,000 pages. The Federal bureaucracy can stagnate from excessive budgets as well. The Interior Department spent $60 million on administering Federal coal leasing in 1981. That's nearly two bits a ton for every ton of coal leased in 1981. You wouldn't stay in business very long if your administrative overhead on inventory was that outrageous. But the pessimism of our critics is apparent from more than red tape and bloated budgets. For decades America has been fasting--consuming too little of America's wealth of minerals, subsisting instead on a diet heavily reliant upon mid-east oil, with little emphasis or concern for inventorying and developing domestic energy and mineral resources. Economics--yes. But short-term, short-sighted economics. Excessively dependent upon foreign imports, of oil, cobalt, chrome and other strategic minerals, the U.S. measures its time before another embargo--or fallen Shah, or Soviet manipulation, or Saudi shift, or, as we witnessed in Egypt, assassination--an untimely loss to mankind and efforts to bring peace to the troubled mid-east. These disruptions, in addition to their tragic human tolls, impair the free world's security. Huge chunks of the United States have been locked away in dozens of single land use categories in the name of conservation, with only the foggiest idea of what resources might be denied the American people-and this at a time of unacceptable levels of energy and strategic mineral imports. More than half and perhaps two-thirds of all Government-owned lands are totally withdrawn from or severely restricted to development under the mining and leasing laws. We must continue to rid Government of the overly zealous restraints which have been keeping us from drawing upon that which can help restore our economy and national security. When we assumed responsibility, the United States was dependent on foreign sources for about 40 percent of its oil. In 1981, our oil import bill was approximately $83 billion--nearly 17 times what it was in 1972. Our reliance on foreign sources for essential minerals is even more disturbing. We must look to other countries--some unfriendly, some unstable--for 22 of 36 strategically critical minerals. Yet the energy resources on federal lands which are owned by the American people could meet our needs for centuries if properly managed. Eighty-five percent of the crude oil yet to be discovered in America is likely to come from public lands, as will 40 percent of the natural gas, 35 percent of the coal, 80 percent of the oil shale, nearly all of the tar sands, and substantial portions of uranium and geothermal energy. Our vast hardrock-mineral wealth includes untapped deposits of essential elements we now import, such as chromium, copper, platinum, and cobalt. The obvious question is, if these abundant resources can help to revitalize our economic strength and to preserve our national security, why aren't we using them to better advantage? To a large extent, the answer can be found in past decisions to restrict public access to the federal estate, thus deferring to us or our successors the tough decisions that flow from Congress' mandate to provide for environmentally responsible development of America's energy and mineral treasures. Here is the legacy this Administration inherited: In January 1981, 7 years after the onset of the Mideast oil embargo: ---Less than 15 percent of federal onshore lands were under lease for oil and gas development; ---No oil and gas leases had been issued in Alaska for 15 years;

Jan 1, 1982