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By A. C. Bluemel, J. S. Harper, J. H. Jett

Can the mining industry in the United States accept the change and challenge of the "Now Generation" of an entirely new high-performance automated transportation system? Advanced transportation systems for the mining industry can be defined as those which lend themselves to automation and meet definite performance and cost objectives. The term automation shall mean that control of transportation system is accomplished by a closed loop electronic circuit which, when started on command, will continue to cycle as programmed until such time as an intelligent feed-back causes the system to shut down.

Jan 1, 1970

By William Hamilton Merritt

At the Atlanta Meeting in October, 1895, a short paper was presented by Mr. R. W. Leonard on the " Assay of Auriferous Ores and Gravels by Amalgamation and the Blow-pipe" (Trans., xxv., 645), embodying the results of some very conclusive tests as to the value of the process. His arguments regarding the desirability of the process appear to be indisputable, but the practicability of the field-outfit used by him is open to question. The Province of Ontario, in which Kingston is situated, is still largely unexplored; and at the Kingstoil School of Mining we give much attention to the instruction of prospectors and the testing of ores. To this end, not only is there a small mill (to which Mr. Leonard alludes) attached to the school, but prospectors' classes

Jan 1, 1897

By Michael G. Schill, Mark C. Fischer

Since its introduction several years ago in the United States, the high pressure belt filter press has proven to be a highly cost-effective dewatering device in a number of mining and industrial applications. To evaluate the process and economic factors associated with the dewatering of coal refuse, a comprehensive program of laboratory and on-site pilot studies has been conducted. This paper will summarize findings of this study and discuss advantages of the belt filter press over conventional dewatering methods. The conventional means of dewatering thickened coal refuse involves the use of vacuum disc filters or centrifuges. Due to the high amount of energy used to dewater refuse with these devices it was a logical course of action to apply belt filter press technology to this application, since a belt filter press will require less than 3.7 kW (connected).

Jan 1, 1982

By C. K. Rose, J. H. East

Proved oil shale reserves in the Green River formation in Colorado, Utah, and Wyoming dwarf present U. S. petroleum resources. Indications are that the appetite for petroleum products will continue to grow and that this potential source of liquid fuels and related byproducts cannot be disregarded. As a part of its synthetic fuels program, the U. S. Bureau of Mines has opened a mine in the richer beds on the naval oil shale reserves. In addition to supplying material for retorting and refining studies, the development of methods, procedures, and equipment for mining oil shale on a large-scale commercial basis is of the greatest importance.

Oct 1, 1955

By Holt, Grover J.

PRIOR to :1937 any discussion of mining and transportation in the iron mines of Minnesota would have been limited largely to conventional methods which have been used for years in the iron ore industry. Today, however, an inspection trip to the crest of almost any open pit on the ranges will re- veal great progress underground mining and the transportation of underground ore have also developed rapidly and if and when underground mining of iron ore again becomes generally economically feasible; these mining methods will probably witness a transformation equal to that which has taken place in the open pits.

Jan 1, 1941

By E. M. MacKevett

The only source of uranium ore in Alaska that has been mined commercially is the Ross-Adams de- posit, a gently inclined, fusiform orebody in alkali granite in which uranothorite and uranoan thorianlte are the chief ore minerals. In mode of occurrence, apparent genetic association with the granite, and to a lesser extent in mineralogy, this type of deposit is uncommon. The mine is in the southern part of Prince of Wales Island (Fig. 1) at an altitude of about 950 ft on the southeast flank of Bokan Mountain. A steep unpaved road 1 ¾ miles long leads to the dock on the West Arm of Kendrick Bay, which can be reached by boat or seaplane from Ketchikan, some 35 miles to the northeast.

Jan 9, 1959

By R. W. Raymond

Jan 1, 1911

By A. W. Fahrenwald

CELL depth has been for many years a controversial question in a flotation-machine performance. In the impeller type of machine, we are really talking about impeller submergence-i.e., the depth in the pulp at which the impeller is required to produce aeration. THE FLOTATION MACHINE A COMPRESSOR A flotation machine can be considered as an air compressor or blower in which the aeration mechanism takes in air under atmospheric pressure[t] (14.7 lb. per sq. in.) and blows it into the pulp (the pulp being the receiver) against a head of 14.7 plus cell depth in feet times 0.4333 lb. per sq. inch. In commercial machines the impeller is submerged in the pulp to depths ranging from about 2 ft. in the smaller machines to as much as 5 ft. in some of the larger ones. In the 2-ft. cell, the hydrostatic head on the impeller is (2 X 1.25 =) 2.50 ft. (assuming a pulp density of 1.25), equal to (2.50 X 0.4333 =) 1.078 lb. per sq. in. For the 5-ft. cell, the hydrostatic head against which the impeller must make air is (5 X 1.25 X 0.4333 =) 2.708 lb. per sq. inch. In the small 2-ft. machine, the volume reduction is (1.078 [-] 0.147 + 0.01078 =) 6.85 per cent and in the large, 5-ft. machine, the volume reduction is (2.708 [=] 0.147 + 0.02708 =) 15.5 per cent. It is obvious that for unit volume of free air intake the larger machine receives a lesser (8.65 per cent less) volume of aeration* than the smaller machine. The bubbles in escaping from the pulp expand and are greater in volume at the surface than at the moment of their formation in the pulp; 7.33 and 18.4 per cent larger, respectively, in the small and large machines. Just how this situation affects flotation is not known. It is interesting to note, however, that the bubbles are smaller in the zone of the coarsest particles and largest in the upper zones of the finer, more easily suspended mineral particles. It would seem that the relationship might be reversed advantageously. The deep cell is at a greater disadvantage in this respect than the shallow cell. Nothing, however, presumably can be done about this situation. The shallow cell is a partial corrective. Not only does the compression ratio of aeration increase with impeller submergence but the hydrostatic head against which the impeller must operate also increases. THE FLOTATION MACHINE AS A PUMP Since, in impeller machines that rely upon their own operation to produce aeration, pulp passes through the im-

Jan 1, 1946

By John G. Roscoe

Continental Materials Corp. operates two under- ground uranium mines in the Crooks Gap district of central Wyoming. Both mines are developed as slusher mining operations through vertical shafts with single level haulage to slusher pocket loading stations. In general, operations at both mines are similar except for depth and some minor details. The shafts are identical in cross-section, each with a 4 ½ x 5-ft hoisting compartment and a 4 ½ x 5-ft manway. Kimberley-type skips are loaded from measuring pockets through air-operated guillotine gates. The Seismic shaft is 245 ft deep and the Reserve shaft depth is 585 ft. The Seismic shaft was sunk in 1957 and the mine has been producing 200 tpd since 1958. The Reserve shaft was sunk in 1960 and the mine is still in the development stage. The hoists of both mines are equipped for semi-automatic operation; that is, they are mechanically controlled to perform a certain cycle of duty and then stop until another cycle is manually initiated. The Seismic hoist, however, was originally a conventional, manually controlled unit; the reserve hoist was installed as an automated system.

Jan 7, 1962

By M. G. Benz, J. F. Elliott

A. J. Goldak and J. Gordon Parr (U)iuersity of Alberta) —Margolin and Ence's paper reached us only a few days after we had submitted a paper on the structure of Ti2Cu to the AIME. Here, however, we only wish to point out an error in the paper (page 321): "Karlsson has reported the crystal structure of the first intermediate phase occurring in the Ti-rich portion of the Ti-Cu system to be face-centered tetragonal." Karlsson actually reported the structure of Ti3Cu (i.e., "the first intermediate phase") to be primitive tetragonal with four atoms per lattice point: Cu at 0, 0, 0; and Ti at 1/2, 1/2, 0; 0, 1/2, 1/2; and 1/2, 0, 1/2. Thus, Karlsson suggests a primitive lattice with an ordered arrangement of atoms located at corners and face-centers: Ence and Margolin suggest a random body-centered tetragonal structure—-with which our results agree. E. Ence and H. Margolin (authors' reply)— We do not agree that Karlsson has not reported the structure of Ti3Cu as face-centered tetragonal. The fact that Cu atoms are located at the corners and titanium at the face-centers does not indicate that the lattice is not face-centered. We are pleased that the discussers' results agree with our own.

Jan 1, 1962

By Fred W. Stiefel

THIS paper covers the operation and maintenance of Diesel locomotives underground on a portion of the Delaware River Aqueduct.[t] This part of the tunnel is 15 miles long, with shafts 14 ft. in diameter spaced about 5 miles apart. These shafts (2, 2a and 3) are 825 ft., 1551 and 840 ft. deep, respectively. The grade of the tunnel is almost level, except for the 12,100 ft. north of shaft 2, which has a grade of 2.31 per cent. The tunnel is circular, 17 to 19 ft. in diameter. It lies at a depth of 400 ft. below sea level, with a maximum over-burden of 2400 feet. The tunnel driving was carried on in six headings, using 15 storage-battery locomotives, each of 13 gross tons and having a maximum speed of 8 miles per hour. The longest haul was 3 miles, which proved to be the maximum distance for which storage-battery locomotives could be employed economically for the amount of material to be moved. One locomotive was used for switching cars at each heading, one for switching cars at the bottom of each shaft and one on the main-line haul from the heading to the shaft. The maximum amount of material hoisted in one shaft from two headings when 104 ft. of tunnel was driven in 24 hr. was 1000 cu. yd., or about 2000 tons of rock in place. The total quantity excavated was 750,000 cu. yd. (1,500,000 tons of rock). The tunnel-lining operations using concrete presented a problem of hauling a maximum distance of 5 miles in the tunnel. The concrete-placing equipment had a capacity of about 2000 cu. yd., or 4000 tons in 24 hours. Experience had shown that storage-battery equipment could not handle this quantity of material within the time required at the distance of 5 miles. Trolley-locomotive haulage was considered dangerous and expensive, and would cause interference because transmission equipment would be required. Therefore the performance of Diesel locomotives of 160 hp., with a speed of 18 miles per hour, in comparison with that of other types of locomotives, was studied. CHOICE OF LOCOMOTIVES In deciding upon the type of locomotive to be used for the 5-mile haul, four alternatives were considered, as follows: I. To purchase additional storage-battery locomotives with the necessary batteries over the 6 locomotives and 12 batteries available. 2. To convert the existing battery locomotives to the trolley type. 3. To purchase new trolley locomotives. 4. To purchase Diesel locomotives. PROPOSITION No. I The 90-hp. storage-battery locomotives available (each weighing about 12 tons), when hauling a load of 64 tons, with a drawbar pull of about 1900 lb. on a level track, developed a speed of 8 miles per hour and could make five round trips in 8 hr. with a

Jan 1, 1942

By David J. Mack, Chin Bea Kim

The decomposition of the Ni-Zn eutectoid at 56 wt pct Zn was studied by isothermal transformation. Its progress was followed by metallographic, hardness, and X-ray diffraction methods. Three transformation products were found: lamellar pearlite at high temperatures; an intermediate temperature structure; and martensite at the lower temperaCures. No transition structu,ves were found. THE decomposition of the Ni-Zn eutectoid at 56 wt pct Zn was stuadied as part of a long-range program of study on the eutectoid transformation in alloy systems which do not have one or more components which exhibit allotropy. Available information on the Ni-Zn eutectoid transformation is limited to that presented in connection with the determination of the phase dilagram. No systematic studies of the eutectoid were found in the literature, alkhough the microstructures of the Ni-Zn eutectoid were reported by Tamuru.3 X-ray diffraction data exist for the ß, ß1, y , and y1 phases.' EXPERIMENTAL PROCEDURE The eutectoid alloy was prepared from "A" nickel shot and Bunker Hill super-purity zinc (99.998 pct).

Jan 1, 1962

By Bryon W. Cheever

While working upon the processes which have been descaribed from time to time in the Transactions of the Institute for the estimation of these elements, I discovered that certain reactions take place under certain conditions which if overlooked, give erroneous results. Some of these reactions are new, to me at least. Estimation of Manganese. A weighed sample is dissolved in nitric acid and the manganese precipitated by potassium chlorate in the usual manner, care being taken to add some strong nitric acid at the last, and boil, to completely destroy the chlorate. Filter through purified asbestos, suck the filter dry with an aspirator; then wash with HNO3(1.40sp). gr.) until the acid comes through clear, and again suck dry with the aspirator. The nitric acid used for washing must be free from nitrous acid, for this acid reduces the peroxide of manganese; the lower oxide thus formed is dissolved by the strong nitric acid and is carried through the filter; some manganese also will nearly always be dissolved if the precipitate is washed with water. The nitric

Jan 1, 1886

By D. L. Martin, E. R. Parker

DURING the heat-treatment of silver specimens for tensile tests it was observed that the bars blistered and became brittle when heated in a hydrogen atmosphere. [ ] To check this unexpected result, a wide variety of commercial silvers were heated in hydrogen at 850°C, Only a few of the materials developed blisters, the most severe of which is the tube pictured in Fig. I. The microstructure of a cross section of the tube is shown in Fig, 2. The embrittlement is extremely severe at the edge; the blisters result from the severe deforma- [ ] tion of the surface material by large underlying gas pockets, The effects resulting from hydrogen embrittlement of silver have been observed by numerous investigators over a long time1,2,3 although it was only recently that a clear explanation was offered ,4 However, the damage resulting from hydrogen embrittlement has not been generally recognized; and it is of advantage to know more about this phe-

Jan 1, 1943

By E. R. Gilbert, D. E. Munson

Creep of copper under 75 to 1.50 kg per sq cm stresses at temperatures near the melting point was found to he a complex reaction controlled by three mechanisms acting in parallel. In order of appearance with decreasing temperature, the auerage activation energies, Qc , are 168, 79, and 24 kcal per mole. Stress dependence of the minimum creep rate was found to he an exponential for the two high-Qc processes and a power law for the low-Qc, process. Transition of control occurs from one mechanism to another. The relative transition temperature depends upon the applied stress, and the range oiler which the transition occurs depends upon the difference in the activation energies of the mechanisms. The creep behavior at high temperature is explained by the climb of dislocations through thermally or mechanically formed jogs, CREEP in pure fcc metals at temperatures in excess of one half the absolute melting point is normally controlled by dislocation c1imb.1,2 A climb model which seems applicable, according to an extensive analysis of data,3 was derived by Weert-man.4 This model assumes jog-saturated dislocations and predicts an activation energy, Qc, nearly equal to that for self-diffusion, USd. Although the requirement of jog saturation is restrictive, agreement between theory and experiment seems adequate. Many other theoretical treatments, including an early model by Mott,5 include detailed consideration of jog formation as an initial requirement for climb. These models predict activation energies for creep which differ from those of self-diffusion. Seeger6,7 postulates an observed activation energy related to the stacking-fault energy. Thus, Usd <Qc<5Usd + Uj where Uj is the jog-formation energy. Seeger incorporated qualitatively the influence of the relative numbers of thermal and athermal jogs. Expanding this concept, Shoeck8 explicitly states a function based on formation mode and relative numbers of vacancies: e r ci exp {-uf/k T} exp {-Um/k T} [ 1 ] where Uf and Um are energies of vacancy formation and migration, respectively. The concentration of jogs, Cj, depends upon the manner of jog production. For intersection jogs, Cj is not sensitive E. R. GILBERT, Junior Member AIME, formerly with De- to temperature; for thermal jogs, Cj is proportional to exp {—Uj /k T}. Schoeck regards each mode as a distinct mechanism; therefore, the mechanisms may act together.299 The diversity predicted by theory, surprisingly, has not been substantiated by experimental results. A significant investigation must include the extremes in stacking-fault energy. Extensive creep studies of aluminum10 and nickel,11,12 high stacking-fault energy metals, have been made. Comparable studies on a low stacking-fault energy metal, such as copper, have not. It is the purpose of this paper to report the results of an investigation of the creep of copper under conditions which favor thermal jogs. EXPERIMENTAL Cylindrical compression creep specimens (0.240 in. in diameter by 0.400 in. long) were machined from cold-drawn rods of electrolytic tough-pitch copper containing 0.0007 Mg, 0.002 Fe, 0.001 Ni, 0.0005 Ag, Cd < 0.005, and Pb < 0.005 wt pct impurities. Undetected spectrographically was a nominal 0.04 wt pct 0, which occurs as a Cu2O constituent distributed discontinuously at grain boundaries. Vacuum annealing at 900°C for 15 min produced a stable 0.03-mm average grain diameter. Testing was carried out using apparatus similar to that described by sherby,13 modified by enclosing platens and a push rod in a vacuum cylinder. Normally this arrangement resulted in pressures less than 10 Only a slight surface tarnish, less than 0.0005 in. in thickness, occurred during the test. The applied stress, corrected for atmospheric pressure, was maintained within 2 pct of the desired true stress by the addition of lead shot at fixed strain increments. Creep strain was measured with dial gages as a relative displacement of the upper and lower platens; accuracy of measurement was 0.0001 in. Two creep-test methods were used, the differential or cyclic temperature14 and the isothermal, to obtain creep data at stress levels of 150, 100, and 75 kg per sq cm over the temperature range of 620° to 1032°C. Minimum creep rates were used from both test methods; this was considered proper because comparable temperature tests or cycling to the same temperature gave the same creep rate, within experimental error. The cold vacuum test chamber, with the unstressed specimen in place, was heated to temperature by placing a preheated furnace over the chamber. Temperature equilibrium was attained within 30 min. For the cyclic tests, the stress was removed during the 5 to 10 min necessary to effect the temperature change and re-

Jan 1, 1965

By Ben L. Seegmiller

Localized open pit slope failure was avoided as an apparent result of a practical rock mechanics program conducted at the Twin Buttes copper operation. The key to the program was the application of cable bolting, a technique that artificially supports open pit slopes using properly installed post-tensioned cables. As a result of the research and testing program, extensions of the cable bolting principal became significantly apparent. • The economics of artificial stabilization appear to be overwhelmingly favorable, and • Best practical applications are "final" pit slopes, slopes beneath permanent structures and potentially slope failing areas. Success of this research is manifested by the fact that similar stabilization systems are presently under consideration for Twin Buttes as well as other open pit operations.

Jan 12, 1974

By Dix, E. H.

THE percentage of manganese used in commercial aluminum alloys is small, and yet this element is an important addition to some very valuable alloys. When used alone with commercial aluminum containing iron and silicon as impurities, the usual percentage in wrought materials is from 1 to 1.5 per cent., whereas castings may contain as much as 2 per cent. An aluminum-manganese alloy containing nominally 1.25 per cent. manganese is much used in sheet form for the manufacture of cooking utensils and other articles requiring a little greater strength and hardness than could be obtained with commercially pure aluminum. It is also used for various purposes in the form of rods, tubes and pipes. The aluminum-manganese alloys, both wrought &apos;and cast, offer excellent resistance to many kinds of corrosion attack. The U. S. Naval Gun Factory uses an aluminum alloy containing from 1 to 2 per cent. each of copper and manganese, for both castings and forgings. Manganese is also used, up to about 1 per cent., as a minor alloying .element in several of the strong aluminum alloys of the duralumin type. It is felt that the role of this element when thus used has not been fully understood, but it is believed that the results obtained in this investigation will throw additional light on the subject. The earlier work on the system aluminum-manganese was general in nature, and no detailed investigations of the relations existent in the useful aluminum-rich alloys have been reported. Guilletl1in 1902 surveyed the system, and Hendrichs2 in 1908 published an equilibrium diagram which, although based on .few data, is often used in the literature. Fragmentary work has also been done by other investigators."

Jan 1, 1927

CENTRAL AMERICANIZATION COMMITTEE Chairman, MRS. C. C. BURGER This committee reports progress in drawing up circulars on the. subject of Americanization, to be sent to all the branches of the W. A. A. I. M. E. It is greatly to be desired that all our members should interest themselves personally in work that can be done among the women and children in the mining districts in the way of Americanizing those of foreign birth or extraction; so much can be accomplished by individual interest and sympathy.

Jan 11, 1918

By E. T. Dumble

The domes of the Texas coastal plain are structural features, consisting of bosses or stocks of salt, gypsum or anhydrite, or of combinations of these, intruding into and occurring in connection with broken and uplifted sedimentary beds of Cretaceous and Tertiary age. Some of these domes show on the surface as mounds of greater or less elevation, while others are only known from drilling records. They may be divided into two classes: interior domes and coastal domes. The interior domes include those which occur in a zone 40 to 50 miles in width lying immediately east of the Cretaceous-Tertiary contact, and extending from the Sabine to the Colorado. With a single exception, these domes, so far as now known, occur in approximate alignment with the contact, but at irregular intervals. East of the Brazos, the domes are entirely surrounded by Eocene sediments. The coastal domes are found nearer the Gulf, lying entirely within Neocene territory and stretching from the Rio Grande to the Sabine. They are much more numerous than the interior domes, and, apparently, are ranged along several lines having a general northeast-southwest direction. No domes are known in the Oligocene belt. INTERIOR DOMES The interior domes so far, identified are Butler&apos;s, in Leon county, Palestine and Keechi in Anderson county, Brooks and Steen in Smith county, and Grand Saline in Van Zandt. In connection with these interior domes we must also consider the Sabine Peninsula,. of Harris, which is, without question, genetically connected with them. The Palestine and Keechi domes have been described recently by 0. B. Hopkins,1 who gives a clear idea of their corn position and structure. Others have been described at different times, and an excellent resume of the literature is given by De Golyer.2 _

Jan 10, 1918

By W. Rostoker, H. Nichols

The embrittlement by mercury of aluminum alloys in various states of anneal, cold work, and aging has been studied. It is shown that single phase and non-precipitation hardened structures irrespective of de,pee of prior cold work demonstrate some small measure of yielding before fracture occurs. Sub-yield-stress failure is confined to the aged state, and embrittlement is accentuated by small plastic prestrains. With large plastic pyestrains, embrittle~nent is progressively reduced. In previous work&apos; it was shown that the propensity of commercial aluminum alloys for embrittlement when wetted with mercury seems to be related primarily to the intrinsic strength in the normal un-wetted condition. The data from a large number of commercial alloys in various states of anneal, cold work, and/or aging gave a generalized relationship. At low strength levels, the wetted fracture strength increases proportionately to the increase in tensile strength; but above 65,000 psi normal ultimate strength, the trend is abruptly reversed, and the wetted fracture stress decreases proportionately to the increase in tensile strength. This paper will demonstrate that the simple character of this relationship between normal tensile strength and wetted fracture strength is fortuitous. It will be shown that structure and thermal-mechanical history are clearly relevant factors. The term brittle fracture has been used to connote the geometry of the fracture surface (transverse vs shear plane) or the negligible extent of preceding plastic strain. At its maximum effectiveness, liquid metal embrittlement can satisfy both criteria—fracture transverse to the axis of tension and without observable plastic strain. In this paper, brittle fracture will signify failure at stresses below the engi-

Jan 1, 1962