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Discussion of the paper of Frank H. Kneeland, Safeguarding the Use of Mining Machinery. By B. F. Tillson and Arthur Williams. 1073 Discussion of the paper of Howard N. Eavenson, Safety Methods and Organization of United States Coal & Coke Co. By William H. Grady, Thomas W. Dawson, C. W. Goodale, J. Parke Charming, B. F. Tillson, George S. Rice, Arthur Hovey Storrs, Harry H. Stoek, Lawson Blenkinsopp, Arthur Williams, and Howard N. Eavenson. 1075 Discussion of the paper of J. Parke Channing, Enlarging the Worth of the Worker and the Perspective of the Employer. By Fred H. Rindge, Jr., S. A. Taylor, Elmer L. Corthell, and Philip W. Henry. . 1095 Discussion of the paper of Walther Mathesius, High Blast Heats in Mesaba Practice. By Joseph W. Richards, W. A. Forbes, J. E. Johnson, Jr., H. P. Howland, and Walther Mathesius. . 1100 Discussion of the paper of W. R. Shinier, Effect of Finishing Temperatures of Rails on Their Physical Properties and Microstructure. By William R. Webster, Henry M. Howe, A. A. Stevenson, G. K. Burgess, and Samuel L. Hoyt . 1107 Discussion of the paper of George K. Burgess and Sir Robert A. Hadfield, Sound Steel Ingots and Rails. By Albert Sauveur, Henry M. Howe, Henry D. Hibbard, Joseph W. Richards, F. W. Wood, and George K. Burgess. . 1112 Discussion of the paper of Henry M. Howe and Arthur G. Levy, Are the Deformation Lines in Manganese Steel Twins or Slip Bands? By J. E. Stead 1116 Discussion of the paper of F. C. Langenberg and R. G. Webber, Structures and Hysteresis Loss in Medium-Carbon Steel. By Henry M. Howe. . . 1117 Discussion of the paper of Charles H. MacDowell, German and Other Sources of Potash Supply. By George S. Rice, Charles H. MacDowell, and V.C. Grubnau . . 1118 Discussion of the paper of Joel H. Watkins, White-Burning Clays of the Southern Appalachian States. By H. Ries 1120

Jan 5, 1915

SINCE I promised you above when speaking of the melting of metals to teach you to make small crucibles and shells for melting, I do not wish to fail in my promise. For, in truth, since they are instruments that are much used for this procedure, they increase the work if they are not good, and often cause great extra expense as well as necessitating repetition of the work. If they are good they save everything. Therefore, if you have to make them, do it so that they, are greatly aided by art. It is first necessary to have the clay of a good nature, that is, resistant to the force of the fire by its own natural virtue, either when it is lean or when its viscousness is mixed with much talc, and whether it is yellow or white. This should be well freed from small stones and beaten well with an iron, and then thoroughly mixed by hand. With this should be mixed an eighth part of finely ground and sifted iron scale,* and also some [145] young ram's-horn ashes. These things should be well mixed together by hand and by beating them. If this clay should not be strong enough by itself, it is mixed with another lean clay, with crushed peperino, flintstone, or some other stone that in your judgment seems to be arid and resistant. Crucibles are worked on a low potter's wheel turned by hand, or on a high one turned by foot, just as plates are made. Both large and small ones are made. Most of them are given a triangular shape at the mouth, and the shells have a kind of spout for ease in pouring out the metal. This done they are well dried, and baked in furnaces like pots or other vessels. At the end, when they have been thus made they are used for melts.

Jan 1, 1942

For some time attempts have been made to improve drilling efficiency (and therefore reduce costs) by introducing certain reagents to the flushing medium. Much of this interest is the result of the Russian book, Hardness Reducers in Drilling, by Rehbinder, Schreiner, and Zhigach, published in 1944. Before embarking on full-scale drilling tests, it was decided to investigate the effects on the tensile strength; these results would help in the selection of the proper reagent and its optimum concentration. Selection of Tensile Strength Testing A drilling system basically performs two separate operations: 1) Breakage of rock. 2) Removal of the broken pieces of rock. Both affect drilling and drill performance but are distinct and separate phases of the process. Causing rock to break during drilling is a matter of generating sufficient stress with a drill bit to exceed the strength of the rock. This strength of the rock may be termed its drilling strength; it is not equivalent to any of the well-known strength parameters. Various criteria have been employed to measure the efficiency of a given drilling system or for comparing different systems and one of the most important criteria is "speed of drilling." Speed of drilling is a function of drilling strength of the rock. Many researchers have tried to correlate the speed of drilling with the strength properties of rock and compressive as well as tensile strength values have been found to give reasonable correlation." As the strength of rock drilled increases, speed decreases. As the Brazilian testing requires the least amount of core, this test was selected. Material Tested Broken Hill lode quartzite has been used in these tests. It is composed chiefly of quartz with varying amounts of sericite, pyrrhotite, chalcopyrite, galena, and garnet. The total porosity of this quartzite is about 11%.

Jan 1, 1973

Discovery of a hitherto unsuspected extension of the Vermilion range iron formation in Northern St. Louis County, Minn., has been announced by the director of the State's geological survey, Dr. George M. Schwartz. USGS aeromagnetic maps show that the Vermilion range curves southeast from the Tower-Soudan area into the wilderness between Embarrass and Bear Head Lake. Dr. Schwartz believes that this new information justifies considerable exploration and drilling for iron ore in an area of about 20 sq miles southeast of Soudan. The aerial maps were a result of a three year USGS-Minnesota Geological Survey aerial search for iron formations in a 30,000 sq mile area in northern Minnesota.

Jan 12, 1950

By James Chapman

THE observations here presented are those, not of an expert accountant, but of one who, while he has seen considerable service in the accounting departments of large companies, has spent more time in engineering and operating. This paper is intended to cover, in a measure, mine accounting for small mines, as distinguished from the elaborate systems, requiring many persons ;n the accounting department. I shall attempt to outline a system embracing the essentials of accounting, and simple enough in form to permit one or two persons to carry it on from month to month, in sufficient detail to be able to tell quickly the grade of ore, the prices received for metals, costs per ton for mining and milling, costs per foot for development, upward or downward tendencies in costs, ore settled or in transit, cash on hand, stocks of supplies on hand, efficiency of' labor, etc. As in all accounting, there are two main divisions: that of revenue received for what is sold, and that of disbursements made for what is bought, so in mine accounting we have to consider chiefly the income derived from sales of ore or concentrates, and the expenses incurred in producing the said ore or concentrates in a marketable condition.

Jan 3, 1916

By Ernest Stütz

(New York Meeting, October, 1913.) THE problem of increasing blast-furnace efficiency through diminution of flue-dust production while operating with burdens consisting largely of fine ores has of recent years attracted the attention of metallurgists, whether directly or indirectly interested in the economies of iron smelting, and the various methods evolved from theory or practice have been. submitted to wide discussion. After the very thorough and, at that time, exhaustive view of the whole subject, which was afforded to the industry by the meeting of this Institute in February, 1912, the subject was again taken up at the meeting of the Verein deutscher Eisenhüttenleute at Düsseldorf in December, 1912. While American and German conditions are not entirely identical, it may be of interest to give here the words of the gentleman summing up the discussion at the Düsseldorf meeting : ?The chief advantage offered by the use of briquettes lies in the fact that disturbances in the furnace, caused mostly by the presence of fine ores in the burden, are avoided, and that blast pressure can be considerably reduced. The resulting economies cannot be overrated, as, with lower blast consumption per ton of product, the installation will be able to take care of increased production. In consequence of lower pressure and speed of blast, heat is more efficiently utilized,, flue gas temperature is lowered, and coke particles are less liable to be carried along with the flue dust, of which considerably less is produced. Finally, by increased regularity of operation and higher temperature in the lower parts of the furnace, the quality of the product is improved. The question of briquetting iron ores has grown to be one of the most important in the iron industry, and it is not any more a question of what is the cost 'of briquetting a ton of ore, but what, in. using ore briquettes, is the cost, of: production of a ton of iron."

Jan 7, 1913

By P. R. Kneitz, G. Yoshikado, D. Zayakov

The design and analysis of a circular, domed powerhouse for Pacific Gas and Electric (PG&E) Company's Kerckhoff 2 Project is described. Exploration, geologic stress determinations, mechanical properties, reinforcement and instrumentation are addressed briefly. The analyses of the circular, domed cavern and the comparison of predicted and field deformations are presented in somewhat more detail. The behavior of the completed powerhouse cavern has been found to be substantially as predicted by the analysis.

Jan 1, 1982

By Peter J. Conroy, Julianne H. Gyarmaty

INTRODUCTION The current study is part of the U.S. Department of Energy's (DOE) on-going subsidence research program. The long-term objective of the DOE program is to develop analytical methods of subsidence prediction applicable over a broad range of geologic and mining conditions encountered in the United States. The DOE currently has several contracts in progress to develop a sound data base that can be used in the development of predictive models. Dames & Moore is currently under contract to DOE to collect and analyze detailed subsidence and hydrologic data from a coal mine employing longwall mining methods in the Eastern Coal Province. Work under Contract No. DE-AC22-80PC 30335 began in October of 1980 and will continue through September of 1984. The contract includes monitoring of two adjacent longwall panels. This paper summarizes the surface monitoring work that was performed through February of 1982. Mining of the first of the two panels (3 off 3 north) was completed on February 3, 1982. Results of the surface monitoring through completion of this panel are presented and discussed. SITE DESCRIPTION The mine being studied is located in eastern Ohio. The site is west of the Ohio River, approximately 56 km (35 miles) south of Wheeling, West Virginia. The topography of the unglaciated region

Jan 1, 1982

ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Graduate mining engineer, with 10 years' experience, having an office in New York, would like to represent a mining company as selling and purchasing agent, and general supervision if desired. Machinery agency considered. No. 259. Member, technical graduate, with several years' experience as engineer for a pyrites company, and as geologist and engineer for copper, nickel, and silver companies, desires a position as engineer or superintendent of mines. No. 260. Member, technical graduate, aged 29, with experience as draftsman, surveyor, and superintendent of iron and gold mines, and as construction engineer, is open for a position as mine superintendent, or in mine examination or construction. No. 261.

Jan 11, 1915

By B. S. Blakeney, E. P. Abrahamson II

The effect of the transition elements in binary solid-solution additions upon the recrystallization temperature of iron has been investigated. All these elements immediately raised the temperature, the majority having their greatest effect in less than 0.10 at. pct. A correlation is noted between the rate of change of recrystallization temperature with atomic percent solute and the electron configuration of the solute element. THE work of Abrahamson and rant' on binary chromium-base alloys indicated that a correspondence existed between the effect of each solute element on the brittle-to-ductile transition temperature of chromium and the ground-state electron configuration of the element added. This was felt to be a bonding phenomenon and would be expected to be observed in measurements of other properties involving the breaking or exchange of atomic bonds. From this work it was postulated that a like correspondence should be found for other properties of binary alloys, such as recrystallization. This study is an effort to check this postulation using binary solid-solution iron-base alloys. Previously, the majority of recrystallization studies were carried out on steels. However, Tammann2 investigated the recrystallization of iron as effected by Co, Ni, Si, Mn, Mo, and Cr and stated that elements with the same crystal structure at room temperature as iron appeared to be more effective in raising the recrystallization temperature. Austin, Luini, and Lindsay3 studied the effects of Ni, Cr, Mn, Co, Si, and Mo on cold rolling and annealing, but noted no trend. Abrahamson and rant,' in their work on the effect of both substitutional and interstitial elements upon the brittle-to-ductile transition of chromium, have shown that the outer electron configuration in the ground state of the solute element appears to be the prime determinant of the transition temperature. PROCEDURE All alloys were made using 99.95 + pct Fe with 0.02 wt pct 0, 0.004 pct C, and 0.001 pct N. All alloying elements were 99.9 + percent pure. Metal-lographically the alloys, out to at least 0.1 at. pct, appeared to be in solid solution. Though several published phase diagrams tend to dispute this.4 All alloys were arc melted six times and cast into square 400-g ingots under an argon atmosphere.

Jan 1, 1961

By H. M. Chance

The failure of the carbonic acid gas method at the Kehley Run Colliery has given rise to a conviction of the inefficienoy of the process ; but a careful survey of the facts, and of the conditions under which it was tried, mill show that a fair trial of the method was not and could not be made at this colliery; its failure in this particular instance therefore, should not be held as evidence against, the process. In itself, thc method seems to be theoretically perfect, but in prac-

Jan 1, 1881

By Keith Leonard Sutherland, Ian William Wark

Mercaptobenzthiazole and its sodium salt are marketed under the trade names Flotagen and Flotagen S respectively, for use as collectors for cerussite and other minerals. The structural formulas for sodium rnercaptobenzthiazole and for sodium ethyl xanthate are: Chemically there is a resemblance between the two compounds, though the free acid (mercaptobenzthiazole itself) is much more stable than xanthic acid. Both are readily oxidized, e.g., by iodine to disulphides, and can be estimated by iodometric titration. Qualitatively they are similar as collectors in flotation, although there are quantitative differences between them that may be important in practice. It is deduced that the influence of the nitrogen atom is subordinated to that of the sulphur atoms, and that the dominant group of these compounds is the mercapto group —SH or —5Na. The general method of investigation has been based on contact tests. Two temperatures, 10" and 35" C., have been chosen, and with a standard concentration of 20 mg. per liter of mercaptobenzthiazole (i.e., of the free acid) the influence of alkali, cyanide and copper sulphate on contact at sulphide mineral surfaces has been studied. This standard concentration corresponds to about 19 mg. per liter potassium ethyl xanthate; it brings out the differences between the minerals better than a higher concentra-

Jan 1, 1939

By Ian William Wark, Keith Leonard Sutherland

Mercaptobenzthiazole and its sodium salt are marketed under the trade names Flotagen and Flotagen S respectively, for use as collectors for cerussite and other minerals. The structural formulas for sodium rnercaptobenzthiazole and for sodium ethyl xanthate are: Chemically there is a resemblance between the two compounds, though the free acid (mercaptobenzthiazole itself) is much more stable than xanthic acid. Both are readily oxidized, e.g., by iodine to disulphides, and can be estimated by iodometric titration. Qualitatively they are similar as collectors in flotation, although there are quantitative differences between them that may be important in practice. It is deduced that the influence of the nitrogen atom is subordinated to that of the sulphur atoms, and that the dominant group of these compounds is the mercapto group —SH or —5Na. The general method of investigation has been based on contact tests. Two temperatures, 10" and 35" C., have been chosen, and with a standard concentration of 20 mg. per liter of mercaptobenzthiazole (i.e., of the free acid) the influence of alkali, cyanide and copper sulphate on contact at sulphide mineral surfaces has been studied. This standard concentration corresponds to about 19 mg. per liter potassium ethyl xanthate; it brings out the differences between the minerals better than a higher concentra-

Jan 1, 1939

A recent study estimates that a 10% improvement in the performance of wire rope used on draglines could save the US coal industry $2 million annually in rope costs. In addition, such an improvement could boost annual coal production by allowing the industry's draglines to remove an extra 1.5 million m3 (2 million cu yd) of solid overburden each year. These findings, although admittedly preliminary, suggest the magnitude of benefits that can be derived from a well-planned wire rope maintenance program.

Jan 3, 1978

By John Fulton

Johnstown is the site of the extensive iron, steel, and wire-works of the Cambria Iron Company. It is situated at the western base of the Alleghany Mountain, 275 miles from Philadelphia, and 78 miles from Pittsburgh. The valley in which the town and its ironworks are located, has an average elevation of 1160 feet above tide water. Johnstown, in its main features, is a modified duplicate of Pittsburgh. It is located at the confluence of the Little Conemaugh and Stony Creek rivers, which, by their union, form the Conemaugh River, just as Pittsburgh is situated at the junction of the Allegheny and Monongahela rivers, which together make the Ohio River. The site of Johnstown is in a cutting through the lower productive coal measures, 500 c feet deep, with steep slopes along the valleylimits, exposing, in sharp-cut terraces, the outcrops of the coal and iron-ore beds; the whole surmounted by the shales and sandstones of the barren measures.

Jan 1, 1885

By C. A. Pierce

Studies of roof and floor movement are of interest to those actively engaged in mining. This is especially true in the case of an entirely new area where there is no precedent for guidance. The potash deposit being mined is in the southeast corner of New Mexico, about 20 miles east of Carlsbad. The deposit was formed by the land-locked, shallow, Permian Sea that extended through parts of western Texas, Oklahoma, Kansas, southeastern Colorado, and eastern New Mexico. The saline deposits vary from 500 to 4000 ft. thick. Neither of the companies operating in this area has delimited its commercial ore bodies. As all production so far has been from Federal and State leases, the Department of the Interior and the State of New Mexico have a direct interest in the development and extraction of these ore horizons. The ore is composed of an intimate mechanical mixture of sylvite (potassium chloride) and halite (sodium chloride). It lies generally in a horizontal bed varying from 5 to 12 ft, in thickness, and has a cover of approximately 1000 ft., consisting of about 500 ft. of salt beds and 500 ft. of sediments. The immediate mine roof for several feet is principally salt with some potash and clayey material. The next 500 ft. above, from the standpoint of structure, may be considered rock salt with a few inter-bedded potash members. The upper 500 ft. is of sedimentary (Permian and Triassic) origin and contains several water-bearing formations with flows varying from 10 to 500 gal. per minute. This water intensifies the interest in convergence problems as the ore and surrounding formations are water soluble. Potash salt (sylvite) and rock salt (halite) are plastic minerals. Plasticity is defined as a "property of solids by virtue of which they hold their shape permanently under the action of small shearing stresses but are readily deformed, worked, or molded under larger stresse."1

Jan 1, 1942

By C. A. Pierce

Studies of roof and floor movement are of interest to those actively engaged in mining. This is especially true in the case of an entirely new area where there is no precedent for guidance. The potash deposit being mined is in the southeast corner of New Mexico, about 20 miles east of Carlsbad. The deposit was formed by the land-locked, shallow, Permian Sea that extended through parts of western Texas, Oklahoma, Kansas, southeastern Colorado, and eastern New Mexico. The saline deposits vary from 500 to 4000 ft. thick. Neither of the companies operating in this area has delimited its commercial ore bodies. As all production so far has been from Federal and State leases, the Department of the Interior and the State of New Mexico have a direct interest in the development and extraction of these ore horizons. The ore is composed of an intimate mechanical mixture of sylvite (potassium chloride) and halite (sodium chloride). It lies generally in a horizontal bed varying from 5 to 12 ft, in thickness, and has a cover of approximately 1000 ft., consisting of about 500 ft. of salt beds and 500 ft. of sediments. The immediate mine roof for several feet is principally salt with some potash and clayey material. The next 500 ft. above, from the standpoint of structure, may be considered rock salt with a few inter-bedded potash members. The upper 500 ft. is of sedimentary (Permian and Triassic) origin and contains several water-bearing formations with flows varying from 10 to 500 gal. per minute. This water intensifies the interest in convergence problems as the ore and surrounding formations are water soluble. Potash salt (sylvite) and rock salt (halite) are plastic minerals. Plasticity is defined as a "property of solids by virtue of which they hold their shape permanently under the action of small shearing stresses but are readily deformed, worked, or molded under larger stresse."1

Jan 1, 1942

By J. H. Frye, J. W. Caum

ONE of the most important methods of increasing the hardness of metals is alloying. In spite of the widespread use of alloys, the fundamental mechanism of alloy hardening is little understood. This is true even of the simplest form of alloy, the primary substitutional solid solution in which solute atoms substitute for solvent atoms at random in the crystal lattice of the latter. A fundamental understanding of the mechanism of solid-solution hardening would be important, both because of the widespread use of alloys of this type and because of the light that might be thrown on the mechanism of hardening in more complicated alloys. The present investigation covers the hardness of primary substitutional solid solutions of zinc, gallium,, germanium; and arsenic in copper. All of these are B subgroup elements from the third period of the periodic table. Cu, Zn, Ga, Ge, and As are in groups I, II, III, IV, and V, respectively and lie just to the right of the transition elements. Because of their cost, it is unlikely that Ga-Cu and Ge-Cu solutions will ever be of commercial importance, but the intent of this study has been to discover some of the fundamentals of solid-solution hardening and it has been demonstrated that such a study is far more likely to be fruitful if alloys are made up on the basis of position of the constituent elements in the periodic table than if commercially important alloys are used. Many investigations have. been made of the hardness of substitutional solid solutions, but lack of attention to purity of the metals, infrequent grain-size control, and the use of varying testing techniques have virtually invalidated any comparisons. The purpose of most investigations has been to solve immediate problems and not to solve the primary problem: Why do solid solutions usually have a greater hardness than pure metals? PREVIOUS WORK Theories have been advanced to account for the hardness of solid solutions,, but relatively little experimental work has been done. Perhaps the first experimental work of merit was that of Norbury1 on copper alloys. He showed that for several alloys there was a correspondence between the hardness of one atomic per cent solutions and atomic volume of the solutions. More recently Brick, Martin, and Angier2 have investigated the effect of various solute elements on the hardness of copper. They concluded that the hardening effect of these solutes depended "primarily on the difference in atomic volume of solute and solvent or, relatedly, upon the parameter, change of the solvent or the extent of solid solubility." They also observed the effect of these elements on hardness and texture developed by rolling and by annealing of rolled material. Austin3 examined the hardness and response to heat-treatment of various iron solid solutions. Frye and Hume-Rothery4 measured the hardness of a number of silver solid solutions containing approximately

Jan 1, 1943

Frank L. Bader has been appointed to the sales staff of Lehigh Navigation Coal Co. in the Philadelphia territory. H. C. Burrell, former coordinator of raw materials, Pittsburgh, Penna., has been made manager of raw materials for Columbia-Geneva Div. of U. S. Steel Co., San Francisco. J. H. Cazier has resigned as general superintendent of Bagdad Copper Corp., Bagdad, Ariz., to devote full time with E. A. Scholz to the operation of the Copper King, Phillips and Black Pearl Mines near Bagdad. They have operated the Copper King zinc mine for more than two years.. Production started from the Black Pearl and Phillips tungsten mines during the past year. Robert T. Chapman has resigned from Reynolds Mining Corp. to join Westmoreland Manganese Corp. as general superintendent. Annan Cook, with Kennecott Copper Corp.'s exploration dept. for the past three years, has been appointed district geologist for the eastern states.

Jan 1, 1952

By David J. Dunn, Richard G. Martin

Of many physical parameters critical to design of grinding processes, impact of grinding media is among the most difficult to measure or predict. Yet impact of falling grinding balls, pebbles, or rods accomplishes the fine grinding essential to metallurgical recovery of most important minerals. Unfortunately, the same impacts that break ore fragments deform or crack grinding mill liners. A project was undertaken at Climax Molybdenum Company to measure impact forces in operating ball mills so that they might be used to calculate stresses in liner materials and be correlated with service performance of mill liner alloys. Towards that end, a method of measuring impact forces on ball mill liners using an instrumented grinding ball has been developed. Preliminary tests show that impact forces and contact stresses imposed on bare mill liners are quite high but are greatly reduced by cushioning when coarse ore particles are crushed between balls and liners.

Jan 4, 1978