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H. W. MussEn, Collingwood, Ontario, Can. (communication to the Secretary*):—Doubtless all engineers who have paid more than a casual visit to Russia have come into contact with that formidable document, the " smieta," or estimate of the Russian manager. It is an institution which seems to be inseparable from Russian mining-methods. As Mr. Shockley points out, the year's costs a agree very closely" with the figures of the smieta made at the beginning of the year. In cases which have come under my notice, I have been satisfied that there had been a good deal of " rigging" of accounts to this end. The sum spent by the manager was carefully kept down to the total of the estimate, because it was well known that no more money would be forthcoming, and when this is done it is not a difficult matter to see that the right amounts come under the right heads in the final accounts. I do not say that this is always the case, but I have come across notable instances. Looking at it from the Russian owner's point of view, I think that the balance of the argument is usually in favor of the smieta as limiting " impulsive indiscretion" on the part of managers. The Russian Mining Code of to-day leaves much to be desired, but this is thoroughly appreciated by the official world there, and great changes are spoken of for the future. In many, if not in most, cases the laws are interpreted liberally, and a great deal is left to the discretion of the district mining engineer or inspector, with whom it is necessary to keep in close touch. As Mr. Shockley points out, the officials of a mine, who are always Russians, are held personally responsible for accidents resulting to employees, quite independently of any compensation which may be made to the sufferer. This seems startling enough, but I have always found that a penalty is imposed only

Jan 1, 1909

Alfred E. Hunt, Pittsburgh, Pa. (communication to the Secretary): My experience has been similar to that described by Mr. Sperry, regarding a 50 per cent. alloy of nickel and aluminum. Moreover, the same phenomena occur with a 50 per cent. alloy of iron and aluminum, manganese and aluminum, chromium and aluminum, or tin and aluminum. It seems that there is a narrow limit of composition of these metals, within which, when they are alloyed, they crumble down into a powder after standing for any considerable time. The resulting powder does not seem to be a separation or disintegration into the elements composing the alloy, but simply a powdering down of the alloy itself. The physical properties and utility of any of these alloys in pondered form have not been carefully investigated as yet, and offer a field worthy of further investigation. Samuel Peters, Pittsburgh, Pa. (communication to the Secretary) : In the early seventies, during the early days of the open-hearth process in this country, the writer was engaged as

Jan 1, 1900

A. 11. P. WYNNE, San Jose de Gracia, Sinaloa, Mex. (communication to the Secretary): In the comparative tests reported by Mr. Tays, the stamp-batteries were provided with various styles and mesh-sizes of screens, while the Bryan mill was run throughout with a slot-punched Russia iron, equivalent to a 30mesh wire screen. This is a somewhat onc-sided method of comparison. Should not the Bryan mill also have had the chance to show what it could do with other screens? I cannot wholly approve Mr. Tays's proposed improvements upon the Bryan mill. In my judgment, the inventor has given us a machine well-adapted to the work for which it was designed, namely, the crushing and amalgamation of soft ores. In my judgment, the principal cause of failure to amalgamate satisfactorily in the Bryan mill is not, as Mr. Tays thinks, the shallowness of the basin, or the lack of copper plate about the inside periphery of the mill, but rather the want of experience and practical knowledge on the part of most amalgamators. Having had experience, not with one Bryan mill only, but with several, and taking into consideration the experience of other capable mill-men, I am positive that the proper way to save gold ill this mill is: first, to use enough quicksilver to keep the amalgam liquid, thus allowing it to accumulate in the annular space between the dies and the rims of the basin; secondly, to replace the old dies, when a little more than half worn-out, with new ones; and, thirdly, to clean up the mill at least every two weeks—or oftener, if rich ore is being treated. It is evident that Mr. Tap endeavored to amalgamate quite " hard," as is done in a stamp-battery, in which case the swash of the pulp would scour off portions of the hard amalgam adhering to the inside plates and dash it through the screens— after which a considerable amount would be lost through floating on, or in, the pulp in its journey over the outside plates, and

Jan 1, 1900

Prof. A. Ledebur, Freiberg, Saxony :* Mr. Sauveur has presented and enriched with original observations a valuable summary of the theories advanced hitherto concerning the hardening of steel; but in one particular, it seems to me, his statements call for correction. He says:

Jan 1, 1898

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 R O. Laidlaw, J L. Mauk

The Coeur d'Alene mining district in northern Idaho, USA is the second largest producer of silver in the world. Mesothermal silver-lead-zinc veins occur in the metasedimentary rocks of the Belt Supergroup with five main types of associated hydrothermal alteration: 1) feldspar destruction, 2) hydrothermal bleaching, 3) carbonatisation, 4) sulfidation, and 5) silicification. Hydrothermal bleaching is characterised by hematite destruction with associated siderite and quartz veins and veinlets, coarse euhedral pyrite and magnetite. Bleached zones envelop both mineralised and barren veins and extend for metres to tens of metres into the wall rocks. Carbonatisation consists of addition of siderite, which occurs as veins, veinlets, stockwork, irregular blebs or spots, and coarsely disseminated grains, depending on the relative distance from the main vein structure. Siderite envelops nearly all mineralised veins, relates to all other alteration types and extends from several metres to tens of metres into the wall rocks. Pyrite and galena alteration dominate sulfidation and are associated with some mineralised veins. Pyrite alteration strongly correlates with siderite alteration and exists in three main forms: a) very fine-grained pyrite flooding, which can extend for metres to tens of metres into wall rocks; b) coarse-grained, euhedral pyrite, which is sporadic and associated with the redox boundary in hydrothermally bleached zones; and c) small isolated zones (6 - 15 cm) of medium-grained, subhedral to euhedral pyrite associated with pervasive siderite alteration. Where present, disseminated galena extends for metres to tens of metres into the wall rocks. Silicification is characterised by veins, veinlets, stringers, irregular patches and variable hardness in siltites and commonly appears in association with hydrothermal bleaching and siderite alteration. Although related to mineralisation, silicification is sporadic and in most places a clear envelope around mineralised veins cannot be identified.

Jan 1, 2001

By E. M. Furness, A. S. Henderson

ORIGINALLY the Babbitt experimental plant grinding circuit consisted of one rod mill 10 ½ ft diam by 12 ft long in open circuit followed by two ball mills 10 ½ ft diam* 12 ft long in parallel circuit. Shortly after operations commenced it was apparent that the rod mill could not function satisfactorily at the required 125 gross tons of ore per hr. Attempts to operate at this rate produced: 1) excessive tramp material over rod mill trommel screen which could not be handled in this open circuit and 2) excess build-up of coarse ore in the ball mill circuits because of inadequate rod mill grinding. Since Reserve Mining Co. ore must be ground to 85 pct -325 mesh to produce a satisfactory iron concentrate, an efficient and controlled grinding circuit is highly important. The first step in trying to resolve this grinding problem was to determine which unit of the circuit was actually in trouble and to what extent. A series of tests conducted at a lower tonnage rate of rod mill feed indicated that one ball mill could grind satisfactorily at rates up to 70 gross tons of rod mill feed per hr.

Jan 12, 1957

By Jack A. James

Lancaster Lime and Stone Corporation developed a quarry operation in 1971 and 1972 for the production of high calcium limestone and construction aggregates, or roadstone. The quarry operation is situated in southeastern Pennsylvania in the northern part of Lancaster County. The geology of the high calcium limestone deposit had a powerful influence on all aspects of planning this operation. My purpose is to trace the influence of geology throughout the planning and thereby point out the discipline that geology imposed on the planning, and indeed, continues to impose on the operation. Lancaster Lime and Stone Corporation is one of four wholly- owned subsidiary companies of Kurtz Materials Corporation. Kurtz Materials Corporation, through its operating subsidiaries, is a supplier of basic materials to the construction industry including crushed stone, ready mixed concrete, concrete masonry units and a wide range of precast and prestressed concrete products.

Jan 1, 1973

R. W. Raymond, New York, N. Y,:—Since the presentation of my note on this subject at the New York Meeting, Professor Louis has pointed out an error in my statement of his conception of " pitch "—namely, he understands the pitch, in the restricted sense which he proposes, to be the angle of inclination of the axis of an ore-body, measured on the vertical plane drawn through the body; whereas, I represented him as proposing to define " pitch " as the angle of inclination of an oblique body, measured on the plane of the dip, in the direction of the strike. The difference will appear upon consideration of the accompanying isometric projection, Fig. 1, in which ABCD represents the plane of the inclosing ore-deposit (vein or bed), and AC the axis of the oblique ore-shoot. ABE is the angle of the dip, as universally understood; and ACE

Jan 1, 1909

By Benjamin Smith Lyman

PAGE I. ANCIENT HISTORY,........... 57 Accepted Fables ; Babylonian Mapping ; First Surveying. II. COMPASS,.............59 Chinese Invention; Marco Polo; First European Compasses ; Early Knowledge of Variation ; Plotting with the Compass ; Hanging-Com pass ; Supposed Gravitational Error ; Merit of the Compass. 111. Telescope,............63 Origin (Roger Bacon, Porta, Digges, Lippershey, Galileo) ; Improvements (Micrometer and Cross-Hairs, Rittenhouse's First Telescope, Platinum Cross-Wires, Telescopic Sights, Reflecting Telescope, Achromatic Lens, Kellner Lens in Erecting Telescope, Inverting Telescope). IV. Theodolite,.............81 Origin ; Derivation of the Name. V. TranBit,.............86 First Surveying Transit; Edmund Draper. VI. Instrument-Parts,..........89 Ramsdenl a Dividing Engine ; Fineness of Graduation ; Conical Gradua tions ; Full Vertical Circle ; Leveling-Screws ; Shifting Tripod-Heads ; Hoffman-Harden Tripod-Head ; Heller & Brightly's Improvements. VII. OTHER INSTRUMENTS AND APPLIANCES,......100 Sunflower; Plummet-Lamp; Chains and Tapes. VIII. SCOTT'S TACHYMETER,.........104 IX. Nomenclature and Classification,.......105 Names; Grouping. Surveyors are much indebted to Mr. Scott for so vigorously attacking the subject of the origin and history of mine-surveging instruments, the compass, the telescope, the transit and other apparatus. He is not afraid of the dark, nor yet foolishly bashful in broad daylight. He does not recoil from the obscurities of the earliest times and the most difficult historical points; and, with commendable public spirit, he makes his own invention known to his fellow-workers, and challenges their criticism. He has, moreover, elicited the praiseworthy emula-

Jan 1, 1902

By S Hayton

While coal seam gas is considered to be an unconventional gas, the proliferation of areas under exploration and development mean that it is rapidly becoming main stream. The potential of New Zealand's coals to produce coal seam gas has been recognised for some time. However, key market drivers have not been suitable for the progression of this potential into reality. Kenham Holdings Ltd and CRL Energy Ltd, recognising the potential for the gas in New Zealand have initiated what is the largest ever assessment of New Zealand's coal seam gas potential. The premature demise of the giant Maui field has raised the focus of new gas developments and has increased interest in what we are doing. Over the past couple of years Kenham Holdings Ltd and CRL Energy Ltd have approached the assessment of the coal seam gas potential in a staged programme. Preliminary assessment of the data on the permit areas indicates that the potential resource may be up to 500 PJ. To date, preliminary appraisals have been completed or are underway on a significant number of fields. Exploratory drilling has been completed or initiated on several of those fields, with results from this work being fed into the preliminary modelling as it has become available. Given that in many of these areas there is no pre-existing information concerning their gas potential and world wide experience with lignite is practically nonexistent, it has been a steep learning curve with many surprises. However, initial gas content results and preliminary gas flow models have been on the whole, rather pleasing, with the commerciality of some developments already apparent.

Jan 1, 2003

By Claiborne C. Van Zandt

THE heavy postwar demand for Portland Cement has created shortages that are gradually being overcome by increases in plant capacity. In the post-war period, the Lone Star Cement Corp. has expanded several of its existing 15 plants and has built 2 new plants, now in operation, with a third new plant under construction in Brazil, of design somewhat different from that of the two preceding ones. The new domestic plants are located at Lone Star, Va., near Roanoke, and at Maryneal, Tex., near Sweetwater, and went into operation during 1951. Each plant is equipped with two rotary kilns and has an initial capacity of 1,500,000 bbl per year, or 6,000,000 sacks. The total cost of each plant was about $10,500,000, and on this basis $7.00 in 1951 money are required per bbl of annual capacity; at 376 lb per bbl, this corresponds to $37.00 per ton of output. The investment corresponds to approximately $80,000 per hourly-wage earner employed. The purpose of this paper is to describe the most interesting design features of the two new and almost identical Lone Star plants. Why the Dry Process Was Chosen The two new domestic Lone Star mills employ the dry process because: 1-The raw materials at both properties are particularly suitable and can be dried very, readily. 2-The Maryneal, Tex., plant does not have water available for slurry. 3-Very substantial kiln fuel savings can be obtained. 4-Dry raw grinding reduces ball and liner wear and- general maintenance, without any sacrifice in power. Operating costs to date have more than justified the choice of the dry process for these two plants. Raw Materials The chemical composition of Portland Cement raw material after crushing, grinding, and mixing, but before burning, is about as follows: [ ] sometimes tailings from an iron ore concentrating plant. Certain objectionable materials occur in raw mix: magnesia, limited in cement to 5 pct, in excessive amounts; alkalies, as sodium and potassium; phosphorous; and sulphur, generally present in coal and oil. The Roanoke raw, materials are dense limestone and shale. The Maryneal materials are soft limestone and a hard brittle clay that can be handled much like shale. Sand and iron ore are required in small quantities. General Plant Layout and Construction The two plants are so similar that one joint description will cover both, with such exceptions as will be especially indicated. The crushing plant is located in the quarry, and raw material is conveyed by belt to the storage building, where all materials are stored and handled. Fig. 1 identifies the various structures of the Roanoke plant. The large storage building is used for the storing and handling of all materials, including limestone, shale, sand, iron ore, coal, clinker, and gypsum. Directly adjoining the storage building is a structure under a similar arched roof, containing the raw and clinker grinding departments and the electrical substation. The discharge ends of kilns and coolers, and coal or gas burning equipment are also placed at one end of the mill building. The 340ft long kilns extend away from the main buildings to form the long leg of an L, at the end of which is the feeding and kiln dust collecting equipment, and the raw blending silos are conveniently located adjacent to the feed end of the kilns. The machine shop, storeroom, electrical shop, foremen's office, service rooms, and meeting hall are combined in one structure in the center of the plant, and the office and laboratory are close by. The cement silos and packhouse do not have to be tied directly into the manufacturing process and are therefore located at a point convenient to the railroad tracks.

Jan 1, 1952

LINN BRADLEY, H.' D. EGBERT and W. W. STRONG (communication to the Secretary*).--In the discussion of the paper, a request was made for a further explanation of the curves given on Chart I. In preparing the curves given on this chart, a typical blast-furnace top gas having the following composition by weight was assumed: Per Cent. C02 21.00 CO 24.00 Hz 0.25 CH4 0:25 N2 54.50 For any given top-gas temperature, Curves A, B, C, D, and E indicate in British thermal units the sensible heat lost in cooling the top gas to 60° F. by wet-cleaning methods. Top-gas temperatures are plotted as abscissae, sensible heats above 60° F. in British thermal units are plotted as ordinates, and separate curves are drawn for top gases carrying various amounts of moisture. For any given stove exit-gas temperature, curves A1,-B1, C1, D1, and E1, indicate in British thermal units the sensible heat carried out of the stoves by the moisture which is left in the top gas when it is dry-cleaned and enters the stoves hot. This moisture is removed when the gases are wet-cleaned and the sensible heat which it carries out of the stoves is therefore saved. As before, separate curves are drawn for top gases carrying various amounts of moisture. The curves in Fig. 1, therefore, indicate graphically how much more sensible heat is conserved by cleaning the top gases by the dry-hot method than is conserved by cleaning the top. gases by a cold-wet method and thus removing the greater part of the moisture carried by them. They also show of how little moment it is from a heat conservation standpoint whether or not the moisture carried by the top gases is removed before they enter the stoves. That wet cleaning secures the removal of this moisture and is thus to be recommended from a heat conservation standpoint is an argument often advanced by advocates of wet cleaning. The curves of Fig. 1 show how fallacious such an argument is.

Jan 6, 1917

By C. W. Hunt

I wish to register strong disagreement with the choices of drilling sites chosen by the Continental Scientific Drilling Committee, while endorsing the stated objectives. Of special significance is the lack of any site involving the metals most needed today in the US, while 9 to 13 km of drilling are allocated to gold and silver districts and 11 to 17 km to base metal (mainly copper) districts. Why is nothing proposed for platinum group or chromite? Is this because the committee did not know of such a site? If so, I offer such a site in California (see Fig. 1). The mineralization shown in Table 1 occurs in a large peridotite body in western Tehama County, CA. Petrography has demonstrated unequivocal evidence of migrated PGE deposited in peridotite and chromite of hypabyssal nature. Active diapirism (due probably to serpentine buoyancy) above a reactivated mantle to surface conduit marks the position of the conduit. Young explosion breccia cemented loosely by volcanic glass and tuff demonstrates the significance of the conduit as the prime source of the various emissions. Deep drilling could result in major metals discoveries as well as shedding light on the grand questions of platinum group mineralization. What role water has played in this occurrence is not yet certain; but chlorine and asphaltite have been detected in and adjacent to native PGM, suggesting a major role for water. The explosion breccia suggests that this excellent site could overlie entrapped geothermal steam.

Jan 1, 1988

By W. L. Cooley, K. Y. Lee, M. M. Hassan

Because power system topographies for surface coal mines are significantly different from those for underground coal mines, the requirements for ground wire monitors for surface systems are somewhat different. This paper analyzes the problems faced by high-voltage ground wire monitors. Based on this analysis, some design requirements for monitors are suggested. Finally, results from laboratory evaluation of some of the commercially available monitors are presented.

Jan 1, 1979

HeRbert A. MeGRaw, San Luis de la Paz, Guanajuato, Mex. (communication to the Secretary*) :—Although Mr. Bordeaux prefaces his paper with the statement-that it is a general outline of practice in the Republic, many of his statements seem to be made from the view-point of a particular case, which does not always agree with general practice. For the purpose of calling attention to some of these variations, I respectfully offer the following comments: The operation of crushing and grinding is performed by so many different methods and systems that it is useless to select any one as the standard. However, primary crushing in rock-breakers followed by stamps is thus far so general that it might be so classified. Whether or not it is the best way, is open to question. Regrinding may be performed by any of the various types of Chilean mills, Huntington mills, or similar machines, or the material may be taken directly from the stamps and delivered to the tube-mills. Mr. Bordeaux's statement that " the slimes can be treated only by decantation; the new Butters slime-filter, as used in Nevada, does not seem to be successful with silver-ores," is surely an error. All over Mexico many of the purely silver-ores are being successfully handled by the Butters or similar filters, such as the Moore and the Burt filters, and a letter to the manufacturers of these filters will undoubtedly bring a list of the silver-ores now being successfully treated in this way. The statement that crushing silver-ores in solution is impossible is equally erroneous. Most modern mills crush the ore in solution, in some cases containing as much as 0.12 per cent, of KCN. I cannot for the moment recall any modern mill in Mexico which does not follow this practice. There may be some reason for it in particular instances, but, generally speaking, the practice is to crush in solution. Care in installation avoids any mechanical loss of cyanide, and the chemical loss is so small as to be negligible.

Jan 1, 1910

By J. O. Marsden, J. H. Gourdie, J. R. Arnold, J. G. Mansanti

During the testing and design of the Gold Fields' Chimney Creek mine, it was found that a much higher carbon loading was possible with CIC (carbon-in-solution columns) than with CIP (carbon-in-pulp). In an effort to keep the carbon handling minimized, an emphasis was put on forcing gold to the CIC circuit rather than the CIP. After considerable study, it was found that a circuit with two thickeners and an interstage leach would force 90% of the gold to CIC. Computer modelling indicates that the benefits of the hybrid circuit include higher recovery, less carbon handling, fewer leach tanks, and lower reagent costs.

Jan 1, 1990

H. 0. Hofman, Boston, Mass. (communication to the Secretary*) :—The experimental demonstration by Professor H. Ries, of the fact that a mixture of clay and finely-ground flux will melt more readily than one in which the flux is less fine and therefore less intimately mixed, is very striking, and will be appreciated especially by those who have to discuss, before classes of students, fusions on a small or a large scale. The statement, that I " rather disputed" the influence of size of flux-particles on the ease with which fire-clay mixtures fused, is an erroneous inference from the paper written by Mr. B. Stoughton and myself in 1898.' We did not undertake to study the influence upon fusibility of the sizes of the particles, either of clay or flux. What we did try to find out was, whether the common practice of finely grinding raw or burnt clay, or a mixture of the two, before testing with Seger cones for resistance to heat and to fluxes, xould give the same results as if the materials were tested just as they were going to be

Jan 1, 1904

By W. G. Davenport

The paper "Copper Smelting to the Year 2000" was presented at the CIM Conference of Metallurgists in Sudbury, August 1979. That paper predicted, in part, that high matte grade, high oxygen smelting - particularly in flash furnaces - would dominate copper smelting until the beginning of the next millennium. The present paper re-evaluates that prediction and examines the changes that have occurred and will occur in copper extraction in the 1990's. Of particular interest is the question as to whether major competitors are on the horizon for flash smelting and Peirce-Smith converting. Recent results with direct-to-blister smelting, lance smelting and submerged-tuyere smelting are reviewed and their roles in future copper smelting are predicted. Requirements for H2SO4 plants which handle the off-gases from modern smelting/converting processes are also examined.

Jan 1, 1993

Joseph W. RichaRds, South Bethlehem, Pa. (communication to the Secretary*): The hold experiment of Mr. James Gayley in drying the blast used in the Isabella furnace has attracted the attention of the whole metallurgical world, and has given rise to a wide discussion of the reasons for its great success. Mr. Gayley and the capitalists who backed him in his work deserve congratulations on the success of the venture, not only because it succeeded, but because they have been rewarded far beyond the maximum that could be expected from theory or probability. To state the case in its simplest terms, all that could have been predicted was: (1) that the removal of the moisture from the blaet would result in the saving of the heat required for its decomposition, representing from 3 to 5 per cent. of the heat-value of the coke used; hence about that quantity of fuel might be saved; (2) that the furnace would be somewhat more independent of variations in the weather; (3) that the campaign would be a little hotter; and (4) that the speed of the blowing-eugines would be decreased, at least in amount proportionate to the reduction in temperature of the air led to them. I do not think anyone anticipated a much larger output per day. The results actually attained were: (1) the furnace made an increase of 24.86 per cent. in the output of pig-iron per day; (2) it consumed 19.6 per cent. less coke per ton of pig-iron made; (3) the blowing-engines were run 15.8 per cent. slower; and (4) the saving in power made up for the power required to run the refrigerating-plant. In addition, the blast was hotter; the waste-gases cooler, because of their smaller volume; and there was a greater proportion of carbon dioxide to carbon

Jan 1, 1906