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By Gunnar Almgren

Hole deviation has great consequences on mining economy, especially for long hole drilling technique. First of all the bore hole datas are concerned but also such factors as development, loss of ore and waste rock dilution are influenced. Hole deviation for sublevel open stoping is illustrated with examples from some mines. The deviations are indicated as mean values but also as standard deviation values, owing to their statistical distribution. The economic influence of the hole deviation is especially studied for steep, small lowgrade orebodies, mined with big hole blasting. Hole deviation can thus influence costs up to US$ 3-4 per ton for operating, development, losses of ore and rock waste dilution. This cost is of the same magnitude as the total operating costs for many sublevel stoping mines. The economic savings in accurate drilling are therefore substantial and are worth all attention.

Jan 1, 1981

By Clifford C. Hanninen, Allan H. Caverson

Within the past nine years a means for measuring the distance between mine roof and floor was developed at the White Pine mine which yields relevant information utilized in the mining operation. The technique known as "convergence" is an efficient, low cost way for obtaining large quantities of data for predicting roof falls, caving activity and overall mine stability. Since 1964 the activity of convergence measurements has expanded to become a production tool found in all sections of the mine. The program involves four types of activity: 1) monthly measurements in areas known to be active and in sample blocks scattered throughout the mine for a long-term stability study; 2) semi- monthly measurements along vital travel roads, belt drifts and compressor sites; 3) weekly measurements in areas where men are working; 4) daily measurements in pillar-recovery and caving operations.

Jan 5, 1973

By M. F. Comerford

M. F. Comerford (Smithsonian Astrophysical Observatovy)- The authors' concern about the effects of preferred orientation is justified and emphasizes a phenomenon that can be a source of serious error, but the cogency of their concluding statement bears close examination. They contend that comparison of intensities from parallel planes of the two phases, as proposed by Averbach, Comerford, and Bever,13 leads to incorrect results. The state- ment is based on the fact that, in Fig. 3, intensity measurements at extreme angles of tilt, (2, lead to different values than those given by the average of all the data. The proposed explanation is that unsuspected superpositions of (110), reflections spuriously enhance the martensite intensity. However, it can be shown on appropriate stereographic projections that no superpositions occur which can affect the reflections in question. Hence, the ex-

Jan 1, 1965

By W. L. Falke, A. A. Cochran

Vast deposits of low-grade manganese ore exist in the United States, yet domestic production is insignificant compared to the more than 2 million tons of ore imported yearly into this country.1 A basic problem in connection with manganese is to find economical ways to utilize domestic resources.2 As a part of its program to conserve domestic mineral resources and to reduce dependence on foreign sources, the U.S. Bureau of Mines has conducted extensive research to broaden manganese technology and to find economical processes for recovering manganese from these low-grade resources. Although a great many processes have been proposed for treating domestic manganese resources, a failing of many of them is that too many steps are involved for economical operation.2 Some of the major processes that have been proposed were reviewed by Norman and Kirby.3,4

Jan 3, 1967

By E. C. Herkenhoff

THIS subject may be controversial. Personal preferences influence the final selection of cyclones, and side issues such as costs, floor areas, head room, and ease of replacing worn parts all enter the picture, but the following comments and data should apply to most cyclone selection problems. Broadly, the uses for cyclones in wet classification may be divided into three fields: 1) Open circuit operation, for two products, in which feed rate and sizing vary and the products vary. For example, feed may be divided into a sand product and a slime product. 2) Open circuit operation, for two products, in which feed varies, one product to have constant sizing. This calls for adjustment in either the apex or the vortex aperture. 3) Closed circuit operation, the finished product to have constant sizing. Most classification jobs fall in this category.

Jan 8, 1957

By Douglas R. Shaw

Normal dodecyl mercaptan was evaluated as a collector for flotation of sulfide minerals and precious metals. The reagent is from the class of normal mercaptoalkanes (n-alkyl thiols), and is commercially available in the form of a mixture of n-dodecyl mercaptan, the primary constituent, and a water-soluble dispersant, under the trade name Pennfloat™ 3. * Reported are results of bench-scale flotation experiments on many commercially treated base metal and precious metal sulfide ores. Dosages, points of addition, and flotation pH were among the variables studied. Most notable results were increased copper, molybdenum, and precious metals recoveries. Dosages of dodecyl mercaptan on some ores were considerably lower than required for conventional collectors. The reagent was shown to be a highly effective and versatile collector on virtually all of the more than 30 sulfide ore types examined.

Jan 1, 1982

By Roscoe Bell

An economic appraisal of the western phosphate industrial potentials made between 1945 and 1948 revealed possibilities for a considerable expansion in the production of high analysis phosphate fertilizer. The most significant facts are: (1) a rapidly increasing and a much larger potential market which might be reached from the western deposits, (2) the existence of large undeveloped deposits of phosphate rock, (3) potential energy from sulphuric acid, coal, or hydroelectric power in the general vicinity of the deposits. The challenge to the mining and metallurgical engineering profession is in the economical development of phosphate mines and in improving processes for utilization of the western ores and the recovery of byproducts to make the expanded western industry satisfactorily compete with the industry in the East and South in meeting the fertilizer needs of the Midwest and Far West.

Jan 4, 1950

By Theron Wasson

The Central Michigan area held first place in the state during the year. Midland and Isabella, the leading counties in 1932, produced most of the oil in 1933. The Porter field southeast of Mt. Pleasant and along the same structural trend saw the greatest drilling activity. In Porter during the year 117 new wells were drilled. Under proration these wells produced 3,583,617 bbl., or nearly one-half the total for the state, which has been estimated at 7,947,695 bbl. The Porter field is already outlined on all sides except the northwest. It probably reached its peak in 1933. Unless a new field of some magnitude is developed in 1934, Michigan will see a continuous decline. The Greendale extension to the old Mt. Pleasant field furnished the new flush for 1932. In 1933

Jan 1, 1934

Receipts General Funds: Initiation fees ' 6,008.50 Arrears of dues 1,772.69 Current dues 46,576.56 Advance dues 1,820.97 Sale of binding 10,554.43 Sale of advertising 6,003.42 Sale of Transactions 3,237.07 Sale of special editions ' 1,722.50 Sale of Bulletins and. pamphlets ' 2,263.95 Miscellaneous Receipts; Interest on investments and deposits 450.06 Sale of pins and fobs 312.80 For the collection of checks 161.84 From Finance Committee, Feb., 1916, Meeting 101.02. Subscriptions to the land fund 86.14 Arizona Meeting refund from N. Y. Central Railroad.. 52.48 Local Section refund from N. Y. Central Railroad.... 31.85 Miscellaneous 425.68 Total Receipts General Funds 81,611.96 Cash balance Dec. 31, 1913 1,063.39 $82,675.35

Jan 2, 1917

By George Schore

Radiation grafting of ion exchange structures contains ion exchange groups but may consist of neutral groups. High energy grafting of monomers on to polymers has-been known since 1950 (1.2); manufacture on an industrial level was-begun in 1970.(3) Proper choice of substrate and monomer will produce various ion exchange membranes with differing physico and chemical properties. Grafting a selected monomer to the proper polymer will provide selective ion exchange with assured chemical protection of the substrate. Ion exchange systems utilizing radiation grafted structures to polymers have been fabricated to "capture" gold from drag-out and rinse water and silver from cyanide rinse water. Other ion exchange systems can feasibly be produced to remove other precious metals. Rotating Cathode Technology is used to recover the metals from their concentrated eluating solutions as pure metal foil.

Jan 1, 1984

By A. T. Yu

Over the last 80 years the conveyor belt has advanced from the troughed rubber belt to those with standard steel cable cores and those which can navigate curves or climb steep inclines. Now the latest generation of belt conveyors can claim hitherto unheard of capacities of 20,000 tph and single flight lengths well exceeding 16,000 feet. The stranded steel cable core belt is principally responsible for the spectacular improvement in load carrying ability of belt conveyors. The allowable working tension of these belts ranges from 2,500 lb per in. of belt width for 1/4 in. diam cable to 4,000 lb per in, for 3/8 in. diam cable. These ratings far exceed the 240 lb per in. per ply for rayon or nylon construction, and 30 lb per in. per ply for a lowcost cotton fabric.

Jan 1, 1970

By Robert P. Uhley, LeRoy Scharon

TEST gravity surveys were made in the Washington County barite district of Missouri on property owned by the Baroid Sales Division of the National Lead Co. This property is located just northeast of Richwoods in the northeastern corner of Washington County, Fig. 1. The area to which the surveys were confined comprised approximately 5000 acres, of which some 525 acres were surveyed gravitationally. Gravity observations were made at 2600 points within the area, observations being confined to relatively clear and gently sloping ground. Part of the area was heavily wooded, and the terrain too rugged for either the occurrence of a commercial barite deposit or a feasible gravity survey. The relief along the central drainage, Ditch Creek, was about 140 ft, the maxi- mum difference in elevation being 400 ft in a distance of 3 ½ miles.

Jan 1, 1954

By W. C. Ellis

For the purpose of developing combinations of higher strength and conductivity than are obtainable by heat treatment alone in the age-hardening copper alloys, an investigation has been made of the effects of combinations of heat treatment and strain hardening on the properties in question. The investigation was limited to a study of the alloys containing nickel and silicon; nickel, silicon and cadmium; and cobalt and silicon. The experiments made in the course of the study are described in this paper in three groups: 1. The effect of hard drawing subsequent to heat treatment on the mechanical and electrical properties of the alloys. 2. The effect of low-temperature aging on the properties of heat-treated and hard-drawn alloys. 3. The effect of strain on the rate of aging of quenched nickel-silicon-copper alloys.

Jan 1, 1931

By D. C. Jillson

THE data on the critical resolved shear stress for zinc single crystals published by Rosbaud and Schmid1 showed many irregularities, as seen in fig. 1. There have been subsequent investigations,2,3 but no one has repeated this work with a wide range of orientations, with specimens of a higher degree of purity and perfection, and with improved experimental techniques in order to determine whether these variations were entirely experimental or whether they might have been due, at least in part, to some feature of the mode of deformation not known or understood. Mathewson4 and others have long felt that the glide observed in a [100]* direction between two (001)* planes in the zinc lattice might be actually the net effect of many consecutive unit glides or movements in two alternating [210] directions (fig.

Jan 1, 1951

By A. Werenfels

After discussing the geology of the Limagne, the surface indications of petroleum, and the recent exploration, the author states that none of the wells were properly located and that oil possibilities of the Limagne have not been adequately tested. NO PETROLEUM, in commercial quantities, is found in France except the small production of the Pechelbronn field (Fig. 1) in Alsace, which produced 75,000 tons in 1923; therefore the test of the petroleum FIG. 1.-KEY MAP. prospects of the Limagne is most interesting. Under the superintendence of M. Termier, chief engineer of the French mines, a well near Crouelle (Fig. 2) was drilled in 1921 to a depth of 856.3 m. (2808 ft.); at different depths favorable showings were encountered. The well, however, was abandoned because of drilling difficulties. A second one is now being drilled near the same place.

Jan 12, 1924

By D. M. Urich

New plant construction for pyrolysis and agglomeration during 1969 has been relatively quiet in the North American scene. U.S. pellet capacity approximates 52 million long tons and that of Canada 25.3 million tons. The foreign scene, however, has been extremely active during 1969, and this is expected to continue for the next several years. Changes in sinter practice have not been reported, other than a few changes towards increased bed depths and the increased use of screening facilities to size the product more closely. Interest in the field of briquetting in fields other than iron ore is high with a new fluorspar briquetting plant under construction at Brownsville, Texas. Considerable research appears to be pointed towards solving the problem of reclaiming steelmill waste products (flue dust, BOF dust, mill scale) by means other than sintering.

Jan 1, 1970

By A. Tanaka, K. G. Carroll

The existence of local room-temperature plastic flow in germanium, which has been a subject of controversy for nearly two decades, has recently received renewed attention, albeit no more agreement than hitherto. Phenomenologically one major facet of the problem has been reduced to the question whether or not indentation can be effected in germanium without the introduction of cracks. That plastic flow can be induced at room temperature by fracture appears to have been rather convincingly demonstrated recently by Suzuki and Kamada and by Noble and Henisch.1 The literature contains both direct and incidental references to Vickers and Knoop indentations showing no cracks, within resolution of optical microscopy. Recently, however, following a controversy on the subject,2,3 johnson4 made a study of indentations produced by spherical indenters and concluded that these are accompanied by cracking. This study in-

Jan 1, 1969

By J. E. Schaffer

Drilling activity in Ohio increased slightly in 1939. There were 1020 completions as compared to 910 in 1938. During the past six years the number of completions has varied little (Table 1). Oil production in Ohio has been gradually declining since 1896, when the peak production of 23,941,000 bbl. was reached (Fig. 1). Since that date production has slowly declined to an estimated production in 1939 of 3,144,134 bbl., the lowest in 53 years. This total production is divided approximately into the following grades of crude oil: Pennsylvania, 1,185,456 bbl.; Corning, 1,261,615 Flg 1. bbl.; Lima, 578,500 bbl.; Lodi, Based on figures of U. S. .Bureau of 104,740 bbl.; Cleveland, 13,823 Mines and Oil andGas Journal bbl. Table 2 shows the prices paid for the various grades of crude oil.

Jan 1, 1940

By J. E. Schaffer

Drilling activity in Ohio increased slightly in 1939. There were 1020 completions as compared to 910 in 1938. During the past six years the number of completions has varied little (Table 1). Oil production in Ohio has been gradually declining since 1896, when the peak production of 23,941,000 bbl. was reached (Fig. 1). Since that date production has slowly declined to an estimated production in 1939 of 3,144,134 bbl., the lowest in 53 years. This total production is divided approximately into the following grades of crude oil: Pennsylvania, 1,185,456 bbl.; Corning, 1,261,615 Flg 1. bbl.; Lima, 578,500 bbl.; Lodi, Based on figures of U. S. .Bureau of 104,740 bbl.; Cleveland, 13,823 Mines and Oil andGas Journal bbl. Table 2 shows the prices paid for the various grades of crude oil.

Jan 1, 1940

By S. R. B. Cooke, R. O. Huch, C. S. Chang

IN the flotation of iron ores laurylamine derivatives have been used for considerable time.12 To effect satisfactory separation of the gangue, predominantly silica, from the iron oxide minerals, the addition of specific depressants for the iron oxides has been found necessary. Starches and starch products have been used for this purpose. 3 There is, however, very little published information on the effects of these materials and other variables on this process. In some cases it has been found that prior acid scrubbing and desliming are essential, 4 and depending upon the efficiency of the subsequent washing step, there will be accompanying changes in pH. It was the object of this investigation to test and observe the effects of the above factor as well as to examine and compare the action of various starches and starch products.

Jan 12, 1953