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By Harlan A. Walker

ROCK-DRILL steel has an important bearing on costs in many mining operations, both directly and indirectly. Direct factors include such items as shop expense, steel consumed per ton of ore produced, cost of distribution and the dust hazard. The latter, although no specific amount may be assigned to it, is an ever-present problem, and is receiving increased attention as the science of mining progresses. Indirectly drill-steel performance affects consumption of compressed air, maintenance of drills and drilling speed. The latter, in turn, increases or retards the tempo of mining and development. These factors, while not all inclusive, are preponderant in their importance. Thus it is evident that in an extensive operation drill-steel expense may run to many thousands of dollars and that thoughtful research leading toward more efficient practice is warranted. EXPERIMENTAL WORK During the late spring of 1939, experiments were undertaken at Homestake in reducing changes in drill-steel gauge from 1/8 in. to 1/16 in. [ ] In drifts and crosscut headings mounted machines were set up and holes were drilled with 1/8-in. bit-gauge changes and other holes a few inches

Jan 1, 1940

At the Gateway Coal Co.'s mine, about 70 miles above Pittsburgh's Point on the Monongahela River, a battery of television cameras stands guard over what is billed as the longest conveyor belt system ever installed in a coal mine. In all, this system consists of 9% miles of 42- in. and 48-in. wide belting, and is capable of transporting 500 tph at a speed of 625 fpm from working face to the tipple located outside the mine. Gateway Coal, located near Waynesburg, Pa., is owned jointly by Jones & Laughlin. Steel Corp. (64% %), Pittsburgh Steel Co. (22lh%), and Shenango Inc. (13%). Managed by J & L, the mine is under a long-term lease from the Hillman Coal and Coke Co., which formerly operated it as the Emerald mine. Hillman produced 700,000 tons per year of metallurgical-grade coal from this mine, but since J & L et al. took over in 1962, annual output has increased to 1.7 million tons. Mine capacity will reach its peak early in 1964 when total production hits an annual rate of 3.1 million tons.

Jan 7, 1963

By W. C. Peters

Geologists take the role of mine geologist when they apply their science to the design and operation of a specific minerals project. In doing so, they use the entire spectrum of procedures in economic geology and engineering geology to deal with a specific system of orebodies and associated environment. The objectives are established by stages in the life cycle of a mining operation as it goes from a prospect to a development project and on to a mine. This paper summarizes the elements of a mining geologist's role, with examples highlighted from the preceding papers.

Jan 1, 1984

By D. W. Kestner

Recent developments and trends in the state of the art as being commercially applied to the pelletizing and sintering of metallic ores, concentrates and reverts will be reviewed. Both ferrous and non-ferrous materials will be covered. The influence of environmental considerations on the decision to build, the process selection, and design of the plants will be discussed. Use of coal in iron ore pellet induration will also be reviewed as the availability and price structure of oil and gas becomes a consideration to the plant operators.

Jan 1, 1980

By Gary B. Williamson, Barton K. Cross

Digital simulation is a modern analysis tool which allows the mine operator to evaluate the result of making a decision without actually changing the organization or buying the equipment. The purpose of this paper is to demonstrate the use of digital simulation in evaluating a decision of whether or not to introduce dispatching in an open pit mine. The analysis shows that appreciable savings can be realized by dispatching. In certain cases, an operator can reduce the number of trucks required to move a specified tonnage. A second analysis evaluates the alternatives of using one large shovel or two smaller units. In this case, the operating cost of the haulage equipment necessary to support the shovels turns out to be the critical factor in this decision.

Jan 1, 1969

FRENCH steel makers are ready to support the Schuman plan. Pierre Ricard, vice-president of the French Steel Chamber syndicate, announced the industry's readiness to cooperate with the plan, which is aimed toward giving Europe an integrated steel industry. Steel men appear to have decided in favor of the plan because of its promise to unify the continent. Behind approval is the emphasis placed by French steel plant operators on continuation of the Franco Saar economic union. The French have an, abiding fear of German steel production potential. France is currently producing at an annual rate of 11 million tons, while Western Germany is producing 15.5 million tons of steel. The Saar output is placed at 3 million tons. French industrialists feel that as long as the marriage of French and Saar steel production continues, France can compete reasonably well with Germany. If Saar production should suddenly become part of the Western Germany total, it could result in an unequal competitive situation, giving Germany a production level of 18.5 million tons of steel annually, or 60 pct more than France.

Jan 1, 1952

By Jack Fox

Last time there was a Take Five in these pages, it dealt largely with the matters considered by your Board of Directors at the meeting on October 20, 1970, in St. Louis, Mo. It was impossible to cover all the points worthy of discussion in the space available. So, at the end of the Take Five in the December issue of [i=], I promised to continue in the next installment. Unfortunately, I was unable to keep that promise. On December 2 your humble servant joined the ranks of those who have suffered a coronary occlusion. While I was away from the office, the very excellent SME staff team that we have built up over the years kept things going without bothering the "old man" unnecessarily. Assistant Executive Secretary, John V. Beall, Mrs. Lillian E. Donaldson, Assistant to the Executive Secretary, Mrs. Ruth Orologio, Administrative Assistant, and Mrs. Alice Ruiz exceeded even their usual dedicated efforts. As a result, the SME came up to the Centennial-Annual Meeting in great shape.

Jan 1, 1971

By W. V. Vietti

Actual field data from several wells are used to illustrate the application of the method of determining the average density of the fluid column in a flowing oil well in the Yates field, Pecos County, Texas. The depths of the wells in the Yates field vary from 900 to 1700 ft., depending on surface elevation and the location of the wells on structure. Production rates over 8000 bbl. per hour have been determined and many wells are capable of producing 2000 bbl. hourly. Gas-oil ratios are usually below 400 cu. ft. per barrel, but a few wells high on structure have produced over 3000 cu. ft. per barrel. Incidentally, tubing wells has cut these high ratios to as low as 400 cu. ft.' By common agreement of the operators all wells making ratios over 400 cu. ft. will be tubed. Daily production of the field is prorated to 110,000 bbl. from an open-flow potential of 5,000,000 bbl. based on hourly open-flow gages.

Jan 1, 1931

By S. J. Mitchell

An analysis of bolting reinforcement of several large [approximately 18 m (60 ft) cube] pillars was performed. The many overcoring stress profiles in pillars at the mine were used to produce generalized stress distributions at various stages in pre- and post-failure. A complete stress-deformation curve was estimated from this data. The effect of pillar bolting on the load-deformation behavior was extrapolated from the observed unbolted behavior. Bolting can increase pillar strength by up to 10 percent. The effect of bolting on general mine stability was examined with a short computer analysis. The computer model was calibrated against measurements performed at the mine, and produced good agreement between measured and modeled stresses. The analysis indicated that bolting increases the bolted pillar safety factors in the event of additional pillar failure by a small amount (approximately 5 percent). Progressive pillar failure is unlikely, because arching transfers most load from yielding pillars to large unmined abutments rather than to the smaller panel pillars.

Jan 1, 1984

No early records of coal in Iowa have been found, although it is very probable that coal along the Mississippi, in the northeastern corner of the state, was seen very early. The United States Census of 1840 showed a production of 400 tons, mined of course in 1839, and the earliest mining, was in Jefferson and Fairfield Counties where the coal was hauled by wagons to shops in the Mississippi River towns years before any railroad was built in the state. In 1840 mines were opened in Van Buren County, near Farmington and Douds, and in Scott County, near Jamestown, all of the product being used locally.' In 1844 D. D. Owen reported seeing mines in the tongue of land between the Rock and Mississippi Rivers, in one of them the coal being 5 to 6 ft. thick, and several other seams south of this locality? In the, late forties a number of small mines were opened in various parts of the state, and in following years in practically every county having coal. The Mystic seam was first opened in 1857 in Appanoose County, since then consistently one of the large producing areas in the state. Consumption was local until the Milwaukee Railroad was built through the county in 1887.1

Jan 1, 1942

By M. M. Fine

In a laboratory study of grinding and classification of silica sand, a satisfactory means of producing the medium-fine specification sand desired by producers of flint-glass containers was developed. The best procedure consisted of ball-mill grinding and double classification, which gave a properly sized sand containing less iron than the feed.

Jan 3, 1950

By T. Sterry Hunt

SINCE: the date of my previous paper on this subject, presented at the Cincinnati Meeting, February, 1881, and published in our Transactions, vol. xii., p. 459, I have had occasion to revisit the Canadian apatite region, and to collect further data concerning its geognosy, which I hope to describe at a future time. At present, I shall put on record a few brief observations concerning the more recent operations in apatite-mining in the Lievre district, to the north of the Ottawa River, where the mines are as yet confined to a small area in the townships of Buckingham, Portland, Templeton, and Darry; the earlier workings having been along the Rideau Canal, to the south of the Ottawa. The large mining operations lately undertaken in the Lièvre district show that the crystalline phosphate of lime or apatite belongs to lodes of great size, which traverse the ancient gneiss of the region. These lodes include a granitoid feldspathic rock, and a pyroxene rock, with large masses of quartz, of carbonate of lime, of pyrites, and of apatite. All of these often show a banded structure, riot unlike that of the gneiss, to which they- are evidently posterior, arid of which they

Jan 1, 1886

By John J. Childress, Russell L. Cook

Stringent environmental regulations, which have limited the use of sludge ponds, coupled with the economic incentive to clean more coal or to add fine coal cleaning additions to existing preparation plants have increased the use of static thickeners in preparation plants. The Lamella Gravity Settler, sometimes designated Lamella Thickener, is a shallow depth sedimentation device which has been applied in a variety of industrial process and wastewater control projects in place of the conventional raked thickeners. This paper presents the theory and design of the Lamella Thickener, as well as describing the operating results from several full scale installations in a variety of Appalachian preparation plants.

Jan 1, 1979

Robert H. Richards, Boston, Mass.: Mr. Goodale calls attention to the difficulty of obtaining clean tailings from the jigs which are fed by the spigots of the hydraulic separator. This difficulty is universally encountered. The Lake Superior copper mills practically overcome it by running the beds of those jigs loose, carrying into the hutch all of the available copper and some sand. These hutches are again jigged upon threesieve Collom jigs, where the treatment is very slow and gentle; and on the successive jigs lighter and lighter bedding is used. The last sieve is run thin enough to let some sand into the hutch. With these precautions most of the free copper is extracted, as well as a fair proportion of the included copper.

Jan 1, 1897

By E. A. Stevens

In a low and gently sloping ridge extending some 1500 ft. southward from Squaw Mt., and now.covered by the buildings, or crossed by the railroads and streets, of a portion of the city of Victor, there is an ancient volcanic vent or crater, which exhibits one of the most interesting phenomena of the great upheaval and volcanic disturbance that built up the hills of the famous Cripple Creek gold-field—of the period when mass was piled on mass to form the mountains and foothills; when fissures and craters opened, and lavas, welling up, overflowed the surface, until, finally cooling, they effectually choked their vents, thus forming many of the ridges that stand out in bold relief, and the dikes that seam the Continent. This particular occurrence, though limited in dimensions, shows in miniature certain stages of the eruptions of Etna and Vesuvius,* Kilauea and Loa; and illustrates what was (with the exception of the penetrating dikes) the closing chapter of the early volcanoes whose emanations have contributed to the

Jan 1, 1901

By G. L. Jr. Spencer

THERE is no question as to the importance of the part played by the retort in modern zinc smelting. A satisfactory retort should have properties that will result in resistance to slagging action and fire cracks, and have no tendency, or at least, only a small tendency, to soften and bend under furnace heat. The life and cost of a retort also are extremely important factors. The trend in zinc smelting during the past few years has been toward longer retorts and higher charge density. This is caused by the fact that the diameter is limited to 9 or 10 in. because of heat penetration difficulties in larger sizes. Consequently, increasing the length of the retort and density of charge offers the only practical means of increasing the amount of zinc produced per retort. The stiffness of a retort perhaps is the most important factor, as slag accumulates in the bottom of a retort which has sagged and very quickly cuts through, often ruining the retorts below. The development of the high-silica retort is a result of the demands made by the trend toward heavy charges.

Jan 1, 1931

By Charles E. Hall

The Crimora mine, operated by the American Manganese Company, Limited, is located 21/2 miles east of Crimora station, 011 the Shenandoah Valley railroad, in Augusta county, Virginia. It is situated in a basin at the western base of the range of mountains which flanks the Shenandoah Valley on the east. This range is composed of the Potsdam sandstone (No. I. of the Pennsylvania survey), and extends in a northeasterly-southwesterly direction the entire length of the valley. The general dip of the measures is westward. The massive sandstone of the mountain is geologically overlaid with shales or slates, which belong to the Potsdam, or lie between it and the Lower Silurian limestone. Throughout this region these shales are decomposed, and form more or less extensive clay deposits, which are found along the base of the range and often underlie a considerable area to the westward of the abrupt slope of the range. Sand and fragments of quartzite occur in considerable quantities on the surface, and often conceal the true character of the underlying formation. The area containing this ore-deposit extends northeast and south-

Jan 1, 1892

By T. F. Witherbee

The Iron Mountain, situated three-quarters of a mile NE. of the limits of the City of Durango, rises abruptly from a level plain, and trends N. 83' E. Fig. 1 gives a view of the mountain, with the company's iron-works. There are indications that the vein or deposit of iron-ore extends also about two leagues across the Murca ranch, in the same general direction. The Iron Mountain proper is divided into two great lenses by a horse of cantera or eruptive rock, some hundreds of feet in width.

Jan 1, 1902

JEROME ALEXANDER.-All of you undoubtedly know that a microscopic examination of metals will reveal many things; but we should go further than just simply using a low- or medium-powered- microscope and seek the reason why grain size varies under different conditions. When we get below the limits of the ordinary microscope, we enter the so-called colloidal field, which means that we are dealing with aggregations of matter that approximate, say, 100 millimicrons. The colloidal dimensions average approximately 50 millionths of a millimeter and extend down to about 3 µµ. This, of course, is beyond the range of visibility in the ordinary microscope. Just to give you an idea of this matter, if 1 cu. in. of platinum is reduced to a sheet five molecules thick, it will cover 7 acres; you can imagine the amount of surface involved when metal, or anything else, is subdivided to so high a degree. Of course five molecules thick is a little below the limits of the colloidal dimensions. The statement is made in the paper that "metals and alloys might be

Jan 4, 1919

By A. G. Metcalfe

THE failure to detect any change in the thermal properties of cobalt at the Curie point would appear to indicate that the apparatus may have a limited sensitivity. The Curie temperature has been determined by direct methods to be 1121+3°CP and 1131°C.3 The specific heat has been determined many times'.' and weighted values are given in Table I. The allotropic transformations in iron and titanium, used by the authors to test the experiment method, involved a volume change of the order of 3 pct on going from the close-packed to the body-centered-cubic lattice. These energy changes are likely to be much larger than those involved in a diffusionless transformation from a hexagonal to a cubic-close-packed lattice. However, it has been pointed out that thermal observations are unreliable in the detection of phase changes when these are near a Curie point.' James 0. McCaldin and Pol Duwez (authors' reply)—The sensitivity of the present technique is limited to first-order transformations, so that gradual changes in specific heat, e.g., in the vicinity of Curie points, are not detected. Furthermore, the existence of first-order transformations with latent heats much smaller than those occurring in the known allotropic transformations of iron and titanium is, we agree, still pending.

Jan 1, 1956