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By G. Stuart Jenkins

Conditions at the properties of the Consolidated Coal Co. had reached a point where improvements were almost impractical. The mines, sunk years ago, had shafts and entries so small as to preclude the use of large mine cars. A radical change was necessary in the type of mining and also in the type of mine to accommodate such haulage units. After due consideration, the company decided to enter the field of trackless mining, utilizing belt conveyors and chain-flight conveyors, the belt conveyors to take the long haul, and the chain-flight conveyors to be used for gathering. It was decided not to sink a shaft, hut to drive a slope on an inclination of 17½°, which the company believes to be about the limit on which coal can be carried on a belt without rolling back unduly. Sinking the Slope It was decided, in sinking the slope, to make an opencut until rock was reached, which was some 65 ft. below the surface, and then to drive the slope through an inclined tunnel from that point. In making the open-cut, the schedule called for the removal of about 25,000 cu. yd. of clay, holding the banks on an inclination of one and a half to one, the thought being to make this cut in a minimum of time, put in a reinforced concrete slope, and then back-fill. Difficulty was experienced because the clay was of a sort that was called "subsiding base" material by contractors visiting the job. In other words, a "squeeze" occurred, the pressure causing the floor of the cut to move up just as it does in many mines where the coal is underlain by thick fire clay and inadequate pillars have been left. It was necessary to move the waste banks back from the edge of the cut 700 or 800 ft., and even then the floor could not be controlled, the result being that almost 100,000 cu. yd. of clay was handled before the rock was reached. A concrete slope was then rapidly constructed, using 95 tons of special-shaped reinforcing iron. The floor of this slope was made 30 in. thick at the bottom, and 17 in. thick at the top, the sidewalls being 18 in.

Jan 1, 1940

By G. Stuart Jenkins

Conditions at the properties of the Consolidated Coal Co. had reached a point where improvements were almost impractical. The mines, sunk years ago, had shafts and entries so small as to preclude the use of large mine cars. A radical change was necessary in the type of mining and also in the type of mine to accommodate such haulage units. After due consideration, the company decided to enter the field of trackless mining, utilizing belt conveyors and chain-flight conveyors, the belt conveyors to take the long haul, and the chain-flight conveyors to be used for gathering. It was decided not to sink a shaft, hut to drive a slope on an inclination of 17½°, which the company believes to be about the limit on which coal can be carried on a belt without rolling back unduly. Sinking the Slope It was decided, in sinking the slope, to make an opencut until rock was reached, which was some 65 ft. below the surface, and then to drive the slope through an inclined tunnel from that point. In making the open-cut, the schedule called for the removal of about 25,000 cu. yd. of clay, holding the banks on an inclination of one and a half to one, the thought being to make this cut in a minimum of time, put in a reinforced concrete slope, and then back-fill. Difficulty was experienced because the clay was of a sort that was called "subsiding base" material by contractors visiting the job. In other words, a "squeeze" occurred, the pressure causing the floor of the cut to move up just as it does in many mines where the coal is underlain by thick fire clay and inadequate pillars have been left. It was necessary to move the waste banks back from the edge of the cut 700 or 800 ft., and even then the floor could not be controlled, the result being that almost 100,000 cu. yd. of clay was handled before the rock was reached. A concrete slope was then rapidly constructed, using 95 tons of special-shaped reinforcing iron. The floor of this slope was made 30 in. thick at the bottom, and 17 in. thick at the top, the sidewalls being 18 in.

Jan 1, 1940

By K. L. Meissner

It is well known that the so-called pure aluminum contains noticeable amounts of impurities, chiefly iron and silicon, and many investigators have studied the forms in which these impurities exist. Hanson and Archbutt1 state that iron exists in aluminum as FeA13 and silicon as elementary Si. The solubility of FeA13 in solid aluminum is practically zero, or at least so small that the smallest trace of this compound is always visible as a separate constituent. Under the microscope an untrained eye can hardly distinguish, without etching, the two constituents FeA13 and Si, but they can be differentiated by suitable etching reagents. Anderson2 also found the same results. At the same time, Merica, Waltenberg, and Freeman3 found a constituent of unknown composition. They found a small thermal effect, at 610" C., on the cooling curves of aluminum with small amounts of iron and silicon. The intensity of this effect increased with increasing silicon content, until an effect occurred at 576" C. due to the eutectic between aluminum and silicon. The authors ascribed the effect at 610" C. to a compound, which they call "X constituent." It was thought to be a ternary compound containing iron and silicon and could be observed under the microscope as dark particles. Dix4 has published unetched photomicrographs of an aluminum with 0.51 per cent. iron, 0.99 per cent. silicon, and 0.32 per cent. copper that shows three constituents: the dark Si (black in the figure), the lighter FeA13, which appears in half tone and crystallizes in needles, and a constituent of the same color as FeAL3 but of different crystal form, often resembling Chinese script. This last constituent, Dix thought, is a compound of Fe and Si; not the compound FeSi but a compound containing a relatively small amount of silicon. Therefore an alloy of aluminum. iron, and silicon (the copper should not be regarded in the following considerations) must contain the following four constituents: Al, FeA13, Si, and a compound of Fe and Si. This, however, does not agree with the laws of chemical equilibrium.

Jan 1, 1926

By Roger H. McConnel

Throughout the world in 1950 there has been extensive exploration for metals, with emphasis on iron, copper, gold, lead, and zinc. Among the features most apparent in reviewing exploration and development are the staggering sums required, the over-riding influence of government policies throughout the world, and the need for intensified search.

Jan 2, 1951

By Freeman Bishop

The Bureau of Mines is working on a long-term program to completely revolutionize mining-to create a mine-systems technology that integrates the need to recover minerals at low cost under safe and healthful working conditions while protecting the environment. Everyone should be brought into the planning process preceding each new mining development, the Interior Department urges, and Assistant Secretary Hollis M. Dole seems determined to push this kind of systems approach with everything he can move.

Jan 1, 1970

By R. N. Kust, J. C. Agarwal, H. E. Barner, N. Beecher, D. S. Davies

Kennecott Copper Corp. has developed a new hydro-metallurgical process for extracting nickel, copper, cobalt and molybdenum from manganese nodules. This process (KCC Cuprion Process) utilizes a reduction leach operating at atmospheric pressure in the temperature range of 45°C to 50°C and has been successfully demonstrated in a continuous Pilot plant processing 350 kg/d of nodule ore. The chemistry, basic flowsheet and operating characteristics are presented and discussed.

Jan 12, 1979

Jan 1, 1929

By R. E. Lund, D. E. Warnes

SELECTIVE sulfation of individual constituents in ores or metalliferous products has received increased attention in recent years. The fluid-bed reactor with its advantages of close control of both temperature and atmosphere promises to have ap-

Jan 1, 1958

By T. A. O’Hara

SINCE May 1948, when tungsten carbide bits were introduced at the Flin Flon mine, they have been popular with the miners because of their fast drilling speed and low gage loss. The high cost of commercial carbide bits and tipped drill steel, however, prevented their use except for the hardest rock. In an effort to extend the use of tungsten carbide on a basis economically competitive with detachable steel bits, experimental work was begun in 1950 to test the feasibility of making tungsten carbide tipped drill steel in the mine drill steel shop. This work showed that tipped drill steel could be made locally at less than half the cost of the commercial product. The performance of the local tipped drill steel was comparable to that obtained with commercial carbide bits and tipped drill steel and the cost per foot drilled was much lower.

Jan 3, 1954

By Waldemar Dyrssen

BEFORE discussing the relation between air pre-heaters and waste-heat boilers in conjunction with the open-hearth furnace, it is necessary to have a clear idea about what a preheater can accomplish and what effect it has on the open-hearth furnace, especially from a thermal point of view. It is generally recognized now that the heating of the combustion air in the checker chambers of the open-hearth furnaces is not as efficient as it is-desirable to make it. It is also generally recognized that heating of the air in checker chambers of ordinary construction has its limitations. These limitations are mostly the .space occupied and the cost that would be involved if checker chambers were made larger than according to present practice. There are, however, other. reasons why checker chambers cannot give the highest possible air temperatures. Checker chambers are capable of heating air to very 'high temperatures by using waste gases of extremely high temperatures and, in fact, higher temperatures can be reached with checker chambers than with any other means available. The temperature to which we can heat, air, however, is limited very materially by -the temperature at which the air enters the checkers, be-cause of the fact that checker chambers, as at present constructed, are not efficient in heating air through a wide range of temperatures. In other words, if air in-stead of entering the checker chambers at atmospheric temperatures could enter at about 1000 to 1200 deg. F., the resultant air temperature at the top of the checker chambers would be materially increased. There are now on the market metallic air preheaters which are ex-tremely efficient for preheating air to about 1200 deg. F. Such heaters occupy very little space and can usually be installed at a relatively low cost.

Jan 1, 1928

By E. W. Henderson

Oil and gas development in Utah in 1936 added nothing of importance to the commercial possibilities of the state and consisted principally of efforts to reach objectives in wildcat wells started prior to 1936. Leasing activity on structures having oil and gas possibilities in beds of Pennsylvanian age or older followed announcement by the Standard Oil Company of California that a test of beds of Mississippian age would be made on the San Rafael structure. DRilling Clay Basin, Dagget County.—The Mountain Fuel Supply Co. completed a third well, sec. 16, T. 3 N., R. 24 E., on a flank of this structure. Total developed open flow of the field is approximately 50 million cubic feet and sufficient reserve has been established to warrant construction in 1937 of a pipe line connecting with the Salt Lake City-Ogden line. San Rafael, Emery County.—The Standard Oil Company of California started a wildcat test in sec. 22, T. 23 S., R. 11 E. Circulation was lost in a water-filled cavity, in dolomitic limestone, below 2185 ft. and the hole conditioned as a water supply for drilling a second test in sec. 27, T. 23 S., R. 11 E. The Carter Oil Co. in 1921 drilled a well in sec. 24, T. 23 S., R. 11 E., which was abandoned at a depth of 3035 ft. after testing at least a part of the Pennsylvanian section. Czsco, Grand County.—Drilling operations at the Utah Sout.hern Oil Company's test in sec. 33, T. 22 S., R. 22 E., continued throughout the year. Information obtained by means of a seismographic survey of the area indicated that beds of Pennsylvanian age would be found at approximately 2500 ft. The bottom of the hole at 6300 ft. is believed to be in beds of Pennsylvanian age but positive determination has not been made froin the drill cuttings. Green River, Grand County.—Test of Glen Ruby et al., sec. 34, T. 21 S., R. 16 E., was abandoned at 2627 ft. as a dry hole after drilling into Permian Kaibab limestone. Shows of oil and gas were reported and a flow of carbon dioxide gas under low pressure encountered.

Jan 1, 1937

By James Humes

The active mines in the Park City district at the present time are the Silver King Coalition, Daly-Judge, Daly West, and Silver King Consolidated. Several other companies, such as the Daly, American Flag, Ontario, etc., are doing considerable development work. In the Silver King Coalition mines the ore is a replacement of a dark siliceous limestone bed, varying in .thickness from 18 in. to several feet. In places the ore has reached a thickness of 25 ft. This limestone bed lies within 100 ft. of the underlying Weber quartzite. There are other lime beds, similar in appearance to this one, in the Park City formation, which is approximately 700 ft. thick; but not one of them has been found to contain any traces of ore. Directly under and in contact with the ore-bearing bed is another, composed of gray lime well studded with dark concretionary nodules; and this one is an unfailing indication of the proximity of the ore-bearing bed. These ore deposits make out from or have connection with some one of the ore-bearing fissures, which were undoubtedly the channels for the circulation of mineral-bearing solutions. It is therefore proper to run prospecting drifts in the fissures, although they seldom contain much ore. As a general rule, drifting in the fissures is not costly. Mining and mucking cost from $2.50 to $4 per foot, and very little timber is required. There are instances, as in the Daly fissure in the Daly-Judge mine, where the expense of keeping drifts open in the fissure is so great that it has proved economical to make the drifts in the foot-wall rock and run crosscuts into the fissure at short intervals. In the Park City mines it is not easy to determine beforehand the best method fir extracting the ore from a newly discovered ore shoot in the bedded deposits. While we may get one dimension from the drift run in the fissure, that will not give us a correct idea as to the other dimensions of the orebody. The fissures here referred to have a N. 35" E.

Jan 1, 1915

By H. P. Reid

Portland cement is manufactured under either of two general processes, the wet or the dry. The raw materials in general consist of limestone, shells, marl, cement rock, clay, shale, blast-furnace slag, etc., so proportioned that when calcined the desired composition will be obtained. In the wet process the combined raw materials are ground to extreme fineness in the presence of water, to a resulting slurry of from 30 to 50 per cent moisture content. The moisture of the slurry may be reduced by thickening or filtering processes for feed to the cement kiln or the slurry may be fed to the kiln with its full percentage of water. The dry process differs from the wet in that the surface moisture of the raw materials is removed prior to grinding. For the drying of these materials heat is required and in most cases is produced by burning of raw fuel either on grates or stokers before the dryers or in suspension in the form of pulverized coal, oil or gaseous fuel. The power required for making the cement is sometimes purchased from outside sources; sometimes it is generated from the heat in the waste gases leaving the cement kilns, or generated at the plants direct from raw fuel. We have, then, as the possible requirements of fuel in the cement industry: (1) fuel for power generation, (2) fuel for drying raw materials, including coal before pulverizing, and (3) fuel for burning the raw materials to cement clinker. There is no essential difference in quality required in fuel for burning the materials by the wet and,dry processes. Fuel fob Power Generation As there is nothing peculiar to steam generation in a cement mill power plant as compared with other power plants this use classification of such fuel will be found in other reports of the Technical Committee. Fuel for Drying Raw Materials and Coal Any fuels capable of producing moderate temperature gases may be used for drying raw materials. There is no problem of material contamination from fuels at this part of the cement manufacture to be guarded against.

Jan 1, 1932

Jan 1, 1928

Jan 1, 1927

Jan 1, 1892

Jan 1, 1948

By W. L. Kendrick

Jan 1, 1957

By Ernest G. Enck

Expanding markets and technological investigations now in progress for commercial production of titanium metal and alloys, as well as expanding uses for the oxide, have resulted in greater production, increased prices, and accelerated search for additional commercial occurrences of titanium minerals. For more than 50 years rutile has been used in moderate quantities in ceramics, in the production of ferrotitanium, as well as nonferrous titanium alloys. During the early 1930's, use of pure titanium dioxide was introduced as an ingredient of coatings for electric welding rods. For technical and economic reasons rutile was soon found to be as good or better for mild steel welding rods, and this use continues to account for a good share of the rutile sales in the U. S.

Aug 1, 1956

By authority of the Secretary of War, and in response to frequent requests, the following suggested list of reading is issued by the War Department for the information of civilian engineers desiring to inform themselves on military subjects: These references have been selected, first, with a view to giving to engineers unfamiliar with the art of war a general survey of that sub-

Jan 1, 1916