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By G. B. SOUTHWARD

MECHANIZATION is being developed to some extent in every coal field in the United States and it is rather difficult to say which State or section of the country has made the greatest advancement. Statistics now being compiled for 1928 will show the tonnage mined, the amount of equipment used in each of the coal-producing States, and the comparative tonnages and percentages of total tonnage mined in each of these States, and will reveal which field is making the greatest advancement as far as quantity of production is concerned. However, while the tonnage figures are of great importance there-are other phases of coal-mine mechanization, such as the types of equipment, the mining methods and coal bed conditions, which are of equal interest. The change from hand-mining practices in all of the various operations from the face to the railroad cars is, perhaps, more indicative than any other one thing of the real progress being made.

Jan 1, 1929

By S. H. Penn

One of the more challenging aspects of the unfolding age of space travel centers about the opportunity for man to use the natural resources of other worlds. The first of the extraterrestrial worlds to be exploited will be the moon. After only a scant few thousand years of scratching the earth's crust, man will embark upon a venture that for centuries has excited the imagination of many (while staggering that of most) and may become a reality within the next decade. There has never been a time when so much money and effort will have been expended to exploit an area about which so little is known. Paradoxically, this effort combines much of the detached objectivity so typical of our analytical time with the proverbial optimism of the indefatigable prospector. As the earliest manned lunar missions will be brief and exploratory in nature, astronauts will not be expected to attempt to exploit any of the possible lunar natural resources. In later missions, with a more extended period of time available for the astronauts to stay on the moon, it may be desirable or even necessary to "live off the land". The resulting exploitation of lunar resources will be intended primarily to reduce the dependence of manned missions upon terrestrial logistic support and to reduce the cost of maintaining lunar bases.

Jan 3, 1966

By C. C. Whittier

CIVILIZATION'S PROGRESS, which has multiplied man's comforts, conveniences, a n d happiness, is based upon the extensive employment of natural minerals and sources of energy. Mineral resources are basic factors in modern economic development, machine industry, international trade and world power. A survey of mineral consumption shows that the United States leads the world in the production and consumption of energy materials, of metals, and of the large and diverse array of earth materials that fall in the nonmetallic mineral group. The use of nonrnetallic minerals exceeded both the metals and the fuels in the long period before the industrial age, but it is only in the last two decades that consumption of non- metals has kept pace with and approximated in value the output of metals. Although the data of production in the first half of the last century are meager and fragmentary, the record of the past fifty years-the period of most rapid growth-is available, and reveals an astounding growth.

Jan 1, 1933

By B. B. Gottsberger

IT SEEMS strange that so many years after the pas¬sage of the first acts requiring registration or licensing of engineers, so few members of the mining branch of the profession are aware of what has taken place. Laws regulating the practice of engineering have now been passed in 19 states of this country, and in many others, such legislation has been proposed. That such laws are necessary for the protection of life, health and property, as is stated in most of them, is doubted by many. That the standing of the engineering profession will be improved by them is certainlyy open to question. That such laws are a welcome addition to the regulation of business by governmental agency, is not likely to be a general opinion. That once more, and in spite of appeals to engineers to interest themselves in affairs of government, an active minority has succeeded in imposing its will on a passive majority, seems but too true. However, the laws are there and information regarding them should be of use and interest to those most directly concerned.

Jan 1, 1921

By E. Douglas, D. N. Collins, J. R. Stevens

E. Douglas (Dept. of Scientific and lndustrial Re-search, Warren Spring Laboratory, Hertfordshire, England) — The authors are to be congratulated on the considerable improvements they have made in tailoring efficiency and selectivity terms which are generally superior to the alternative forms in current use. However, I feel that their efficiency expression is limited to lower-grade feeds; its accuracy reduces as the feed grade increases. For example, its application to such processes as the beneficiation of glass sands, refractories and clays will invoIve considerable inaccuracies. The reason for this lies in the direct use of recovery, which, with high-grade feeds, biases their empirical expression, R(1 - c/h). With a 90% grade feed, the recovery weighting for the slightest degree of beneficiation, over a zero efficiency sampling operation, will be 90+%+ I disagree with their second basic requirement which states that there can be no fundamental basis for any single quantifying expression. A formula giving a comprehensive representation of concentra- tion efficiency can be derived fundamentally accord-to the procedure outlined in the literature. '' This formula, called the Basic Efficiency formula, is

Jan 1, 1963

By AIME AIME

NEW YORKERS look forward to the third week of February as the time of the year when they can count on seeing their friends-from far and near gathered in the city for the four-day annual session of the Institute.., Indeed, the metropolitan district is so large that in engineer who lives in New, Jersey and has his office on the lower end of Manhattan island may easily pass a whole year without seeing an acquaintance who lives in Westchester and has an office near Forty-second Street. If the Institute served no other function than to provide a place where friendship may be renewed, ideas exchanged, and new acquaintances made it would still be worth while. But when about 30 technical sessions at which about 160 papers are read and discussed are compressed into four days the annual meeting is also entitled to high rank as an intensive course of post-graduate instruction in the newest development in mining and metallurgical technology. Last, but not least, it is the occasion of a good time for one and all, even if they do get more than a little behind on sleep before the end of the fourth day. Nine o'clock is the time set on Monday morning for the beginning of registration, but a half-hour before that a number have always 'put in an appearance, and this is fortunate, because by 10 o'clock four sessions had begun, those on mining methods, geophysics, a round table on the valuation of coal, and the session of the Local Section delegates. Three committees of the A. S. T. M. were also in simultaneous session, so the meeting may be fairly said to have started "in high."

Jan 1, 1931

By E. A. Holbrook

AS A whole, engineering schools have not awakened A to the fact that the workmen compensation laws passed in most of our states between 1914 and 1917 effected a quiet but none the less real revolution in. the relations between labor and management; no longer are industrial accidents unfortunate or careless happenings over which we feel a humanitarian interest and sorrow, they are a cost of the process and the finished product, as vital as improved design and increased efficiency. Last year the writer and others made a committee report to. the American Institute of Mining and Metallurgical Engineers on the cost of accidents in the coal industry of Pennsylvania. Comparatively the accident record in Pennsylvania coal industry is not high, yet the direct compensation cost plus the interference with operation cost of accidents was over 5 per cent. of the total cost of producing the coal. This stands out more vividly -if you realize that about 70 per cent. of the' cost of producing the coal is for payment of labor, wages that are fixed and over which engineering efficiency and management skill have little or no direct effect. This leaves 30 per cent. of the cost chargeable .to hoisting, haulage, overhead 'and other items subject to engineering control. One sixth of this is due to cost of accidents. Surely a direct place 'for an engineering attack.

Jan 1, 1925

By G. Ferrara

The reserves of lead and zinc ores in the metalliferous district of Iglesias in south-western Sardinia are today estimated at about 30 million tons, grading from 4 to 10% Pb + Zn. Of these reserves, about 40% are in the mines owned by AMMI Sarda S.p.A. The working of these resources goes back to ancient times. Not infrequently, traces of old Roman workings and remains of ancient implements are come upon in the higher parts of some of the ore bodies. Exploitation of these mines on larger scale, however, dates from the middle of the 18th century. Initially, the more accessible zones of the ore bodies and the richer ores were worked - the galena and the rich oxidized ores (calamine* with 25-35% Zn), which were often found in large masses, the enormous empty cavities of which still remain. The poorer grade deposits have been gradually rendered workable by the development of technology - the perfecting of the

Jan 1, 1970

By Mark R. Lamb

THE treatment of slime is of special interest to those engaged in cyaniding gold- and silver-ores. The usual practice is to make as small a percentage of slime as possible. In many instances the slime is given no treatment, but is impounded in dams in the hope that the future will develop some method of economically treating this product. The filter-press was the first step upward from ordinary decantation, but, on account of heavy labor-charge and high cost, its use has been limited to high-grade material. The slime at the Combination mill at Goldfield averages perhaps $20 per ton, and although the values are quickly dissolved the filter-press installation was not entirely satisfactory, resulting in the erection of the canvas-cell filter, developed by Chas. Butters and his staff. This filter is a great improvement over the filter-press, and the following description of it will be of interest to those engaged in treating slime produced in crushing ores, especially in view of the fact that, by the use of this filter, slime can be treated at a lesser cost and with a higher percentage of gold- or silver-extraction than in the ordinary treatment of sand; and, moreover, the initial outlay for an all-sliming plant is less than that for the ordinary sand- and slime-plant. The economy of construction of the Butters filter-plant is clearly shown in Figs. 1 and 2, which illustrate the 20-frame filter of 40 tons capacity, now being installed by the Nevada Goldfield Reduction Co. In this construction the slime-pump is so connected that it can pump to or from either tank or the filter by changing the valve-settings-a combination which is necessary in this particular installation, since sufficient fall is not available for filling and discharging the filter by gravity. Ordinarily, a slime-plant comprises: a filter-box with frames

Jan 1, 1907

By H. Merton Ruth

THE northern anthracite fields, although facing the same economic problems as the southern fields, are confronted with the additional problem of fast dwindling reserves of anthracite which can be conventionally and economically won. The mining of coal which remains in thin beds and the recovery of pillars from areas heretofore considered unrecoverable, either by reason of cost or surface restriction, pose problems of in- creasing importance to the economic life of the northern field operations. Successful approaches have Been made to this problem and other work is being performed that holds promise. There exists in the northern anthracite field millions of tons of solid coal, the recovery of which has not been too successful due to the following inherent operating faults: inability to concentrate producing areas; the great quantities of rock to be cut and handled, lack of consideration of proper sequence and speed of second mining, and the continued use of the mine car as the basis of payment. A mining system that has successfully solved these major problems has been in operation in the Scranton area since 1944. Over 1% million tons have been produced from veins varying from 3 to 4% ft thick by this method, which is known as the multiple panel-triangular system-conveyor mining.

Jan 1, 1950

By A. B. Kinzel

SILICON and its metallurgical uses have been the subject of speculation since the earliest days of modern civilization. The early philosophers, Theophrastus and Pliny, believed that silica was a special form of ice, an opinion that was not seriously challenged until the seventeenth century. The first comprehensive view of the nature of silica was advanced by Lavoisier in 1787. He assumed silica to be an oxide of an unknown metal. In 1808 Berzelius produced ferrosilicon by heating silica, iron and charcoal. Probably the first produc¬tion of crystallized silicon was in 1854 when H. St. C. Deville accidentally produced the material while electrolyzing a double chloride of aluminum and sodium containing siliceous impurities. It is not strange that the early investigators should have given so much attention to silica and silicon, because of the great natural abundance of the former. Although silicon does not exist in the elemental state in nature, it has been estimated that the lithosphere contains approximately 60 per cent silica; quartz and rock crystal are found in practically every part of the world.

Jan 1, 1933

By M. G. Jones

AT the Edwards mine a 4 by 81/2-ft two-compartment shaft is used for men and supplies in the older workings down to the 900-ft level. All ore is hoisted through a 5 by 15-ft three-compartment vertical shaft which extends to the 1500-ft level. Ore pockets are on the 1300- and 1500-ft levels. The two-compartment countershaft used below the latter level is 6 by 12 ft inclined at 42°. Ore from the countershaft is hoisted to the 1350-ft level where it flows by gravity to the 1500-ft level ore pocket. One-ton skips are used in balance in the countershaft and two-ton skips, also in balance, from the 1500-It level to the surface. These skips are slung under the man cages. Each level has an ore pocket of 200 tons' capacity. Development at Edwards is similar to that at Balmat except that haulage drifts are only 7 by 7 ft. They are mucked with Eimco-Finlay No. 12 loaders. A drill carriage similar to that used at Balmat is being tried out on the new 2300-ft level, the present bottom of the mine. Drifts are driven below grade and later raised 6 in. and ballasted with waste leaving a ditch 6 by 12 in. at one side for drainage. All development is done on an incentive bonus system, the miner paying for his explosives.

Jan 1, 1947

By Raymond L. Jones

With the inauguration of open-pit copper mining in Bagdad, Ariz., plans were formulated for a large scale leaching operation. Dump stockpiling was started almost immediately, but actual production was not initiated until spring 1961.

Jan 9, 1977

By T. H. Aldrich

THE Aldrich Mining Co. holds under lease from the Illinois Central R. R. Co. about 14,000 acres, in the East half of Township 12, Range 12 `V., in Marion county, Alabama, and owns other lands, of which about 1,000 acres adjoin this leased tract, making a total area of about 15,000 acres, all of which is underlain by the coal-seam upon which the company is operating. This seam is nearly horizontal ; and a ravine, diagonally crossing the tract, exposes the outcrop on either side for about 2 miles. The territory has been so divided that nearly the whole of it can be worked out by two collieries. The mines at Brilliant were opened in the Fall of 1898, and shipments began in the following spring. The original plan was to furnish steam-coal for locomotives to the Illinois Central R. R. Co.; and upon this expectation the investment of capital was made. The field was entirely new; and the softness of the coal at the outcrop induced the belief that it could be very cheaply mined. A contract for the delivery of a large quantity of coal to the railroad was accordingly executed. But with the advance of the entries to increasing distances from the outcrop, the coal proved so hard that it could no longer be drilled with a breast-auger; and the expense of mining became so great that the contract for cheap steam-coal had to be cancelled. It became evident that the work must be done with machinery and explosives, if it could be profitably done at all. On the other hand, the excellent quality of this coal opened, at the same time, a possible market not specially contemplated at the outset-namely, that of a first-rate coal for domestic and general uses. Since no other deposit of such coal was known to exist on the line of the Illinois Central, or any other railroad

Jul 1, 1906

By F. F. Schmidt, H. R. Ogden, E. S. Bartlett

Continuing tantalum alloy development studies have been concerned with a more detailed investigation of promising binary, ternary, and more complex tantalum alloys containing Groups IV-A, V-A, VI -A. VII-A, and VII-A metal additions. A primary objective of these studies was to improve the elevated temperature strength of tantalum with minimum degradation of fabricability and low-temperature ductility by alloying. Several alloys were found to exhibit hot tensile strengths in the excess of 25, 15, and 10 ksi at 2700°, 3000°, and 3500°F, respectively, combined with excellent cryogenic toughness and ductility. Particularly outstanding in this respect are alloys in the system Ta-Mo-W. Ternary parameter curves describing hot-strength, low-temperature ductility, recrystallization temperature, weld ductility, and fabricability are presented for the Ta-Cb-V, Ta-Hf-W, Ta-Mo-Hf, Ta-Mo-V, Ta-Mo-W, and Ta-V-W systems. At present, only four metals qualify for large scale structural applications at temperatures above about 1800°F. These are tungsten, tantalum, molybdenum, and columbium. Research and development work on these refractory metals has progressed to the point where efforts are now primarily directed toward the improvement of high- and low-temperature mechanical properties through alloying. High melting point combined with excellent low-temperature ductility, fabricability, toughness, weldability, and high solubility and tolerance for both substitutional and interstitial solutes are important attributes of tantalum. Conversely, its high density and relative scarcity compared with other refractory metals are the major deterrents to the use of tantalum. Early studies in the Battelle alloy development program established base line data on the mechanical and metallurgical properties of high-purity tantalum.' These studies were extended to include a preliminary investigation of the effects of various alloying elements on the established base properties.2,3 Recent studies involved a more detailed investigation of promising binary alloys containing Cb, Hf, Mo, Os, Re, Ru, and W, and ternary Ta-Cb-V, Ta-Hf-W, Ta-Mo-Hf, Ta-Mo-V, Ta-Mo-W, and Ta-V-W alloys. Results of major importance obtained are given in this article. EXPERIMENTAL PROCEDURES Electron-beam-melted tantalum (Wah Chang) and high-purity alloying elements were consolidated as 150-g ingots by multiple nonconsumable arc melting under a partial atmosphere of helium. Homogeneity of the button ingots was checked radiographically. Alloy buttons measured about 1-1/2 to 1-3/4 in. in diam by about 0.35 and 0.50 in. thick. Nominal alloy compositions were checked on each alloy button by weighing after arc melting. In most instances, weight losses were within 3 pct of the total weight charged. Subsequent chemical analyses on a number of selected alloys showed interstitial contents to range as shown below: Range of Interstitial Content, ppm 0 C N H 25-75 50-100 10-50 1-5 Metallic alloying additions were found to agree well with nominal compositions based on weight change data. Fabrication directly from the cast button to sheet was conducted at low (75° to 900°F), intermediate (1800° to 2000°F), or high (3000°F) temperatures, depending upon alloy content and hardness. Evacuated stainless steel or molybdenum packs were used for fabrication at intermediate and high temperatures, respectively. The temperature required to complete recrystal-lization in one hour was determined by hardness measurements and metallographic observations (longitudinal test sections) after vacuum annealing at 180°F intervals in the range 2010° to 2910°F. All mechanical property evaluations were conducted on recrystallized sheet, nominally 0.04 in. thick. Weldability of the various alloys was screened using manual TIG welding techniques. Bend ductility (bend axis perpendicular to weld axis) was the criterion used for evaluation. Tensile specimens employed 0.200 by 1 in. gage lengths, and bend test specimens measured about 1 by 1/4 in. Low-temperature tensile tests were conducted using a crosshead speed of 0.02 in. per min up to the point of yielding, and 0.05 in. per min to fracture. High-temperature tensile tests were conducted in vacuum using a crosshead speed of 0.01 in. per min

Jan 1, 1963

By Tell Ertl

TODAY'S mining industry is witnessing a transition in labor utilization. The drill-jumbo operator, the mucking-machine operator, the blasting crew, the scaling and timbering crew are all specialists. The all-around miner is rapidly disappearing. As mechanization has resulted in a higher order of underground skills; specialization of labor has been a natural consequence, as has the need for more supervision and engineering. Mines now are cleaner, neater, safer, and have a greater productivity per man-shift than ever before. Nothing spectacular like the continuous miner has yet come to the underground metal mines, but t a gradual improvement in methods, equipment, and technical knowledge is achieving the increased efficiency. With the exhaustion of the rich ores and large profits and who-cares-about-the-costs, mining has become a business; that of producing low value ores at costs below selling price. Charles A. Chase, patriarch of Colorado mountain mining men, manager of the Shenandoah-Dives, was one of the first to preach and prove his preachings that mining is a business. He has been mining a lead-copper-zinc-gold-silver ore, much from elevations above 1.3,000 ft, for a quarter century without a shutdown.-The ore is of such low value that most engineers and investors still would consider it foolhardy. Yet he has kept Silverton, Colo., alive, has paid wages without a lapse, has produced $25 million of new wealth and maintained a steady return to the investors. This type of responsibility is increasingly apparent in the mining business and is one feather that can be worn proudly. .Much emphasis is being placed on improving, the productive mining operations-breaking, loading and transportation. Breaking in underground metal mining is done by drilling and blasting. To the writer's knowledge, no chain or rotary-type machine has been developed for mining strong, abrasive rock. Drilling Percussion drills are still the standard drilling machines underground. Diamond drills, that: were the rage a decade ago for drilling long holes, are being superseded by the rock drill. The development of the hard abrasion-resistant carbide bit permits full-gage long holes to be drilled by percussion drills at a lower cost than diamonds. The change in the use of percussion drills is chiefly in the method of mounting. The column and arm are disappearing and the jackleg and rubber-tired or track-layer jumbo mountings are taking its place. At the Homestake mine .lightweight jackhammers mounted• on pneumatic legs using 7/8-in. hexagonal drill. rods and 1 1/2-in, tungsten-carbide detachable bits have been found more portable and maneuverable. They have less air consumption, lowered, dynamite consumption, and more footage and tonnage per man-shift than with 3 1/2-in. drifters on a column mounting. Drills now are mounted on longer feed carriages, drilling up to 20 ft without changing steel. These mountings result in great savings because the driller can set up quickly, drill the entire depth of the hole without changing the drill rod or bit using carbide and one-use bits, and can move his machine quickly to the next hole. One man to the machine is becoming general practice. The result is longer rounds rounds drilled at a lower cost than the previously used short rounds. A jumbo developed in the Tri-State can be extended to mine ore left in the roof up to 65 ft above the floor. Drill-rod life was formerly considered to be about 250 min of actual use. The increase in the drilling time per rod per day has gone up considerably with the development of the jumbo and the long-feed carriage, resulting in which is apparently more rod breakage., Consequently, a great deal of research is being done in the attempt to develop an alloy-steel rod with longer service life to offset the greater cost. Some reports indicate that alloy steel or Swedish steel results in cheaper drilling than conventional drill rod. However, several tests have shown only slightly increased life for alloy drill rod. Undoubtedly, the blow of the rock drill, the length of the drill rod, and the resiliency of the rock being drilled are important factors in the life of drill rod, so it follows that alloy steel might work well in some mines and result in no savings in others. The bit forged on the drill rod is seldom encountered and steel detachable bits are not as common as in the recent past. The one-use bit is gaining popularity because of. the difficulty in rehardening reconditioned steel bits satisfactorily. It is thought that the, carbie-insert bit is most applicable to drilling hard 'rock' where the steel bit is unable to drill out a full change, for instance, in extremely abrasive

Jan 1, 1952

By AIME AIME

AMONG the recent mining and metallurgical developments in England great interest has been shown in the development of an iron-ore field covering 26,0.00 acres in Northamptonshire, containing 500,¬000,000 long tons of ore; and the erection at Corby, by Stewarts & Lloyds, of a modern basic bessemer steel plant and tube works. The entire project was planned to cost about £3,300,000. Many improvements have been made in the varied equipment that is being installed, some of which has set mew records for massiveness. There is, for instance, a new roll crusher, which has been manufactured by Hadfields, Limited, of Sheffield, the largest ever built in England, and weighing 130 tons. This machine, shown in Fig. 1, as erected at the Hadfields shops, is primarily designed to take blocks of iron ore as they come from the steam shovel. The maximum size is 54 by 48 by 36 in., hut occasional pieces slightly larger than this may be accommodated. The capacity is upwards of 500 tons per hour, the product passing to a secon-

Jan 1, 1934

By Francis L. Vinton

THE eccentric theodolite I exhibit is one constructed by the Stack-poles of New York, from drawings, considerably modified, of Combes's theodolite. The telescope is on one side of the horizontal limb, and the vertical circle is opposite to the telescope; thus they nearly balance each other, making already the construction lighter than in the instrument of Combes, where the telescope and vertical circle are together on the same side, and are both balanced by a considerable weight. The instrument stands upon three levelling screws or feet, an improvement upon the old or general style of mounting a transit on four feet-for indeed the instrument is easier levelled, and, more-over, stands more stable on three than on four points of support. The general advantage of an eccentric theodolite is evident, namely, that it can measure any and all vertical angles, from 0 to 360, without being interfered with by the horizontal limb as is the transit; besides this advantage, it needs no preparatory adjustment or correction for eccentricity ; on the other hand, however, that correction

Jan 1, 1873

By Francis L. Vinton

THE eccentric theodolite I exhibit is one constructed by the Stack poles of New York, from drawings, considerably modified, of Combes's theodolite. The telescope is on one side of the horizontal limb, and the vertical circle is opposite to the telescope ; thus they nearly balance each other, making already the construction lighter than in the instrument of Combes, where the telescope and vertical circle are together on the same side, and are both balanced by a considerable weight. The instrument stands upon three levelling screws or feet, an improvement upon the old or general style of mounting a transit on four feet for indeed the instrument is easier levelled, and, moreover, stands more stable on three than on four points of support. The general advantage of an eccentric theodolite is evident, namely, that it can measure Any and all vertical angles, from 0 to 360, without being interfered with by the horizontal limb as is the transit; besides this advantage, it needs no preparatory adjustment or correction for eccentricity; on the other hand, however, that correction

By H. C. Goodrich

AT THE Utah Copper mine, steam shovels were first used, in 1906, for the removal of overburden, and in June, 1907 for the mining of ore. Prior to 1907, the ore came from underground development work and from stoping. The use of the steam shovel gradually increased until 1914; since then all material, both overburden and ore, has been loaded by power shovels operating on the various benches of the mine. During FIG. 1.-SCENE OF UTAH COPPER MINE BEFORE OPEN-PIT MINING WAS BEGUN. these 19 years, there has been a great improvement in open-pit mining; largely in the use of equipment having greater capacity and dependableness. The history of the development of mechanical shovels and related equipment, as affecting the Utah Copper Co., would be interesting and would justify considerable space; but of greater interest at this time is the operation of the equipment now in use. The Utah Copper mine is in a great deposit of copper-bearing monzonite, which occurs as a prominent headland of the Oquirrh range of

Jan 9, 1925