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By H. J. Winters

Position of the Porphyries in US Copper Supply The United States continues to be the largest producer and consumer of copper in the world. [Table 1] shows several production statistics for 1974, the most recent year that the non-communist world copper industry might consider a good year, and for 1976 and 1977. In 1974 an estimated 24% of the non-communist world's newly mined copper was mined in the US, and 87.89% of that was from the western porphyry coppers. In 1976 US new mine production was down to 22% of the non-communist world's newly mined copper, and the percentage of US new mine production supplied by the porphyry coppers had risen to 89-91%. In 1977 the statistics remained the same as in 1976. US porphyry copper production represented about 65% of US refined copper consumption in 1974, rose to 75% in 1976, and dropped back to 61% in 1977 as imports of foreign copper into the US began to swell. The financial situation of the porphyry copper mining industry continues to be very unhealthy. To see why; we can take a quick look at costs and prices.

Jan 1, 1982

By Axel Sahlin

The day is long past when linen and cotton rags were the exclusive raw material of the paper-trade. Wood-fiber, chemically or mechanically prepared, straw, hemp and Esparto grass have largely supplied the demand, which the old materials did not suffice to fill. But even these newer fibers have been of late supplanted, to some extent, by mineral pulp. Weighting and filling materials have also been resorted to, partly to give body to the fabric, partly to increase its weight and reduce the cost per pound. China clay, sulphate of lime and soapstone have generally been employed as loading materials. Even though these materials lack fiber, their addition must by no means be viewed, as it too generally is, entirely as an adulteration. No doubt, to a certain extent, they weaken the paper ; but for ordinary grades the addition of these non-fibrous substances is a positive advantage, as they close the pores between the fibers and lend to the paper a great degree of opaqueness and a superior finish. Fibrous talc, as a form of pulp, has the same effect, without appreciably weakening the paper. When, therefore, some fifteen years ago, fibrous talc in large quantities, and of marvellous purity and whiteness, was discovered in the neighborhood of the town of Gouverneur, it was not long before the

Jan 1, 1893

By John Sherbourne

Much valuable scientific research has been performed in recent years on the subject of phase behavior of hydrocarbons. ? 1-11 Engineers employed in petroleum production are interesting themselves in this work as well as in methods of applying the fundamental data available to the solution of their various problems. Recently a number of papers have been published in which applica-tions of phase behavior have been made to specific cases pertaining to critical phenomena.)12-16 Little effort, however, has been made in the literature to show the relation between changes occurring in the critical region and the more common phase behavior, therefore it is believed that a presentation of the fundamentals of phase behavior with reference to hydrocarbons is timely. Study of phase behavior is not new. In the metallurgical field, knowledge of heterogeneous equilibria has advanced tremendously, particularly with reference to solid-solid and solid-liquid behavior. Much is known about vapor-liquid equilibria too, but few engineers are familiar with this subject. ?

Jan 1, 1940

By G. A. Alers, F. Borik

Rolled sheet products are elastically anisotropic and a large number of measurements of Young's modulus and rigidity modulus are necessary to completely specify their elastic properties. This paper describes and uses a simple measurement technique to obtain the nine elements of the elastic modulus tensor from which all the elastic The elastic properties of a polycrystalline material are usually specified by giving the Young's modulus E and the rigidity modulus G. Unfortunately, these two moduli by themselves are insufficient to completely specify the elastic properties because the rolling process introduces a preferred orientation which makes the material properties can be deduced. In particular, the variation of Young's modulus and the rigidity modulus in the principal planes of a sheet of ausformed steel were deduced. Furthermore, the variation of Young's modulus in the rolling plane was compared with direct measurements. anisotropic. This anisotropy makes E and G functions of the orientation of the test specimen in the sheet so that a complete description of the elasticity requires many measurements on a large number of specimens. A more fundamental approach to the problem is to consider the sheet as a single crystal and measure the elements of its elastic modulus tensor. Although this appears formidable, there have been developed recently high-frequency ultrasonic techniques which yield these tensor elements directly. The symmetry of a rolled sheet is such that it behaves elastically as if it were an orthorhombic

Jan 1, 1965

By Byron Pickard

AT MIDNIGHT of Sunday, Aug. 27, 1922, a fire was discovered in the main shaft of the Argonaut mine, Jackson, Cal. With the excep-tion of a shift boss and two skip tenders who escaped, the entire night shift of 47 men was trapped in the mine and entombed for 22 days, when the bodies were recovered. The entombed miners made a valiant but fruitless effort to save their lives. Rescue crews toiled strenu-ously day and night for 21 days to save the entombed men, only to find they had arrived too late. From the experiences of the entombed miners and of the rescue crews, valuable lessons may be learned to prevent future catastrophes.

Jan 11, 1922

By Dorsey Hager

THE information given in the accompanying table is submitted as evidence confirming the application of the anticlinal theory and the value of geology in the Kansas and Oklahoma oil fields. The term anticline has been used to define a particular type of arched fold. The anticlinal theory of oil accumulation should, however, be broadened to include any structural fold of an arched type even if not a distinct anticline. A terrace may very properly come under the heading of the anticlinal theory of accumulation, as the folding is closely related to that of the anticline; in fact, in many cases is an arrested anticline, though not completely closed in all directions. Stratigraphic forms due to lensing or irregular cementation of the sands certainly cannot be considered to fall within the anticlinal theory, though the laws of accumulation may be similar. A dome is similar to an anticline and belongs to the same class. A dome is broader in proportion to its length than an anticline. Many anticlines undulate along their axes to form domes. The anticlinal theory in this discussion will then be applied to anticlines, domes and terraces. In the following list, the writer has tabulated the main oil fields of Oklahoma, and a few recently discovered fields in Kansas. The fields discovered within the past 4 years are listed with the date of their discovery. Under "How found," the writer puts "Wildcat" where a geologist has not been employed, "Geology" where it has been used, and "?" where there is doubt. In some places the geologists have claimed pools that may rightly belong to them, but their claims have been questioned, so that they belong in an unsettled category.

Jan 2, 1917

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from Sept. 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The 'Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be. of service to the Library by forwarding copies of mining reports, maps privately issued; and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members, while in the city will use, the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 12, 1915

By James R. Grage

The lead deposits of Missouri may be divided into three districts, the southwest, middle, and southeast. As too much time would be required to devote a detailed account to each district, only a description of the modes of occurrence of the lead ores in the southeast district will be given. The lead mining region proper of Southeast Missouri is embraced in an area of about twenty-five miles in width by about one hundred in length. The country embraced in this district is very broken, and traversed by ridges from one hundred to three hundred feet; in height, with an occasional knob rising higher. Porphyry forms almost the entire substructure of the region, with here and there outcrops of granite. The crystalline rocks were eroded into ridges and valleys before the deposition of the limestone took place. These porphyries are older than the Silurian limestones, and " belong (according to Pumpelly) to the Archaean (Azoic) formation, of which they may be the youngest member in Missouri. They are the near equivalents, in point of age, to the great iron-bearing rocks of Lake Superior, New Jersey, and Sweden."

By Jan M. Mutmansky, Gordon H. Walrod, Y. J. Wang

The selection of a shaft size for ventilation purposes is a classic problem of concern to mining engineers. This presentation is concerned with the sizing of conventionally-sunk circular shafts with concrete or shotcrete linings. Costs of sinking shafts of three different depths, from 150 m to 300 m (500 ft to l000ft), and six different diameters, from 4.27 m to 7.32 m (14 ft to 24 ft), were obtained through questionnaires to shaft contractors. The primary objective of the economic model presented is the balancing of detailed annual capital and operating costs to achieve the minimum overall cost of the shaft installation over its life. The economic model is similar to previous analyses but treats several of the individual cost categories in an updated fashion. Included in the paper is a detailed analysis of the effects of varying power costs on optimal shaft size. Also included are a statistical analysis of current shaft costs and comments on the choice between shotcrete and concrete linings.

Jan 1, 1980

By Hugh Rose

JAY A. CARPENTER, Tonopah, Nev: (communication to the Secretary*).-This description of the Santa Gertrudis mill is of great interest to the operators of similar silver mills in Nevada. At the San Francisco meeting last September there were two excellent papers presented on Nevada silver mills; one by A. H. Jones on The Tonopah Plant of the Belmont Milling Co., and the other by E. E. Carpenter on Cyaniding Practice of the Churchill Milling Co., Wonder, Nev. At the same meeting, I presented a paper on-Slime Agitation and Solution Replacement Methods at the West End Mill, Tonopah, Nev., covering this .particular feature of our milling practice. A comparison of the data presented in these four papers is interesting in that, while the general design and practice is much the same in all cases, there is a wide difference in the design and practice in the various departments of 'the mills. It is to be regretted that Mr. Rose did not round out. this excellent article by following Mr. Jones's and Mr. Carpenter's' lead in giving the average gold and silver content of the ore milled and the resulting tailing, with the consumption of chemicals and the? cost of milling. The practice of the Santa Gertrudis mill in the use of ?cyanide and zinc offers an interesting comparison with that of the Nevada mills, and a discussion of this point may bring out the reasons for the differences that exist.

Jan 12, 1916

By T. Inoue, T. Imaizumi

A simulation model has been developed to find out the possibility of improving the industrial closed-circuit wet grinding operations. The model involves a continuous tumbling mill in combination with a hydrocyclone to recycle the oversize material back to the mill. The mill is described by the breakage, i.e. the selection and the distribution, functions, co-ordinated with the diffusional mixing along the axis. The cyclone classifier is characterized by the partition function with allowance for the non-selective separation of part of the feed material into the underflow. The computer program developed incorporates an interactive capability to modify the operating conditions of the system whenever needed. The results are analysed for the operational conditions characterizing the mill and the classifier. Besides the steady state conditions some observations are also made about the dynamic responses of the closed circuit grinding system.

Jan 1, 1980

By W. Blaschke, E. Malysa

INTRODUCTION In recent years in Poland, a problem connected with the occurrence of a considerable amount of liberated galena grains in size fractions under 1mm has arisen in the zinc-lead processing area. Operating practices have included crushing of ore particles under 0.2 mm followed by flotation. Jigs were applied to separate the concentrates from size fractions under 10 mm and to prevent the galena overgrinding. However, the fractions being too wide, the jigs have not worked effectively, in spite of the great differences in specific gravities of galena, blende and gangue minerals. Fine galena grains move into light fractions in considerable amounts and hence are overground. Therefore, the flotation becomes difficult and galena is lost in its tailings. These losses could be avoided by introducing separation in the grinding and classification circuits. The amount of 0-1 mm fraction is great; therefore, the application of concentrating tables or other kinds of jigs is impossible from an economic point of view. Taking these factors into account, the possibility of application of pinched-sluices was investigated. These are simple devices without moving parts, they have a high output for the unit areas, and their water and energy consumptions are low. In this paper, the results of zinc-lead ores beneficiation in pinched-sluices are presented.

Jan 1, 1980

By Gloyd Wiles

THE eastern section of the Park City dis-trict is drained to an elevation of 6300 ft. by means of the Ontario drain tunnel owned and maintained by Park Utah Consolidated Mines Co. This elevation represents a depth of 920 ft. in Park City Consolidated Mines Company's property. When development below the goo-ft. level was commenced, sinking was at-tempted through an incline winze in the fissure. The intensely fractured quartzite forming the walls of the vein could not be held after water was encountered, so it was decided that further sinking should be done in a vertical winze far enough in the foot-wall to be in the more solid quartzite out-side the fractured zone containing the vein. Progress was good until a depth of 200 ft. below water table was reached, where the flow of water became serious. Sinking pro-gressed 300 ft., to the 1200-ft. level, and there approximately 750 gal. of water per minute was being pumped. The last 20 ft, of sinking cost more than $200 per foot direct charges, whereas the over-all cost for the 300 ft. was $100 per foot. This high last cost was caused by excessive lost time in pumping. Crosscutting to the vein disclosed the fact that the 1050-ft. level had been devel-oped only after drainage had been effected from the 1200-ft. level, but that the 1200-ft. level could not be opened because of the

Jan 1, 1940

In their presentations Dr. Puddington and Dr. Stratton-Crawley have concentrated on spherical agglomeration and two-liquid extraction respectively. I should like here to complete the picture by putting these two techniques together in context with other techniques in which non-polar oils are used in the concentration and separation of minerals. Although these techniques are invariably treated separately and have been studied in isolation, there is a lot to be said for considering them together and trying to systematize their similarities and differences. This I take as a principle guideline in my introduction to this discussion. Four processes can be distinguished on the basis of the dosage of oil required: --simple flotation with collector-extender --agglomeration (emulsion) flotation --spherical agglomeration --two-liquid separation Dr. Stratton-Crawley has suggested that "pigment flushing" could find application in the treatment of ores. This is an interesting suggestion. However, the process can be regarded as a variant of two-liquid extraction, and it is convenient for me to do so in this discussion. Table 1 sets out some main features of these techniques. The first, in which the oil is used to enhance the strength and reduce the dosage of the collector is not designed for and has no special advantages in the treatment of fines, and therefore will not be further treated here. To add to the details appearing in the Table, thumbnail sketches of the other three, which all do show particular efficacy in the treatment of fine particles, are given below.

Jan 1, 1979

By Orr Hamilton

VALUATION of a mine is an approximation of its true cash value which requires the application of fundamental principles of economics. Mines are valued from necessity, for the following reasons: (a) Transfers of titles. (b) Dissolutions of partnerships or corporations. (c) Mergers of mining companies. (d) Appraisals for the purpose of State and Federal taxation. (e) Establishment of the fact of worth as a basis of loans. (f) Determination of values as frequently required in litigation. (g) Listing of stock for sale by a reputable stock exchange. For the majority of purposes a valuation is required as at the present time, but for some purposes valuations as of bygone times may more nearly reflect the intrinsic worth of a mine because its subsequent history can never be, entirely ignored, but valuations made as at the present time are better indicators of cash values. Many mines with great intrinsic worth have been sold for small cash prices. The object of legitimate mine valuations is to deter-mine salable value, or that price in cash at which a transfer of the property from a willing seller to a willing buyer might be consummated, assuming that both vendor and vendee have knowledge of all pertinent data and that the owner, is not forced to sell at a sacri-fice-the definitions of fair market value precluding a forced sale.

Jan 11, 1923

By Howard M. Wells

The investment worth of a mineral deposit can only be realistically evaluated in relation to specified engineering design criteria which fully detail the proposed method of exploitation. The operational design of a mine falls essentially within the technical discipline of the mining engineer, under the constraint that the technical design should be aimed at optimizing the financial attractiveness of the project. In the case of a marginally viable proposition it becomes vitally necessary to identify the best set of design parameters which together will add up to an optimum investment proposal. This paper examines some fundamental logic of optimization for a "wasting asset" type of investment such as a mine, with special reference to the rate of annual production and the strategy of selective mining.

Jan 1, 1979

By Ashbel Welch

Ashbel Welch, Lambertville, N. J.: Dr. Dudley has given the wear of steel rails under four different conditions. He arrives at the conclusion that the softer rails, or those that from their composition ought to be softer, wear better than the harder. But there is another condition which has an important bearing on the subject, and should not be overlooked,—the weight on a wheel. With the lighter weights of the past, the softer rails may have worn best; with the heavier weights of the future, the harder may wear best. Weights will probably be increased up to the capacity of steel to bear; then doubtless the harder steel will wear best. A leaden rail with ten pounds on a wheel might carry millions of tons, but with one hundred pounds on a wheel, it would be destfoyed by a few thousand tons. So in the days of iron rails, my experience was that the softer rails under light machinery stood better than some of the harder; but under heavy machinery the softer were much the most rapidly destroyed. It is doubtless the same with steel. The pounding motion of the wheels loosens or spreads the particles of a thin film of steel; the pull lengthwise on the rail de-

Jan 1, 1881

ARTHUR H. STORRS, Scranton, Pa.-I would like to ask whether this same process is applicable to bituminous coal? FELLS A. VOGEL, New York, N. Y.-This Dutch process is applicable to bituminous or any other kind of coal. The Berwind Fuel Co. has had a plant in operation, in Superior, Wis., for about 2 years, using the Dutch process, and it has made a very satisfactory briquette, using Pocahontas coal. There is just one item in Mr. Frey's paper I would like to discuss; that is, the matter of cost. Mr. Frey figures a total cost of $3.35, based on the use of 7 per cent. of oil. Of course, the price of oil has advanced seriously within the last year or two, and any possible reduction in the percentage of oil required in the manufacture of briquettes is very important. I believe that Mr. Frey will agree that very good briquettes can be made with considerably less than 7 per cent. of oil; in fact, actual experience has shown that it can be clone with less than 5 per cent. The only possible effects of a low percentage of oil, particularly in anthracite briquettes, are that the briquette might not burn so freely, and that it might not be quite so hard. Briquettes made by the Lehigh Coal & Navigation Co., using 7 per cent. of binder, are extremely tough. Those briquettes have been handled in one of the local yards in Brooklyn, chuting them from railroad cars into boats and digging them out by grab buckets, and the losses average less than 2 per cent. This compares very favorably with domestic anthracite coal, with which the losses from breakage amount to between 7 and 10 per cent.

Jan 4, 1918

By Abbas Ali Daneshy

A study of the mechanics of hydraulic fracturing shows the fracture initiation pressure to be a function of the in-situ principal stresses, the formation and fluid properties, and how the wellbore has been completed. The orientation of the hydraulic fracture is perpendicular to the least in-situ principal stress. The geometry of the induced fracture depends on the treatment fluid properties, the injection rate and volume, fluid leak-off and formation properties.

Jan 1, 1974

By Robert Anderson Cook

The subject of refractory materials occupies such an important position in all metallurgical works, and particularly in those of iron and steel, that any data concerning it must be of interest to the metallurgist. No apology is needed, therefore, for this attempt to describe the mining of fire-clay and the manufacture of fire-brick at one of the largest establishments in this country. Mount Savage is a small village situated in the northwestern part of the Cumberland coal basin, on the Cumberland & Pennsylvania Railroad, and at the foot of Savage Mountain, from which the village takes its name. Fire-brick have been manufactured here almost, if not quite, as long as in any place in America; and as the brick are still shipped to nearly half the States in the Union every month, the manufactory is probably the most generally known. In the year 1837, a company was formed called the Maryland & New York Coal & Iron Company. It built two blast-fiirnaces, the ruins of which still remain. It was in the construction of these filmaces that the first fire-brick made here were used ; and though the iron works ran but spasmodically, the brick works have been in constant operation ever since. From 1837 until 1846, the Maryland Coal & Iron Company, from then until 1548, the Lochiel Iron Co., and from 1848 until 1861, the Mount Savage Iron Co., ran the brick-works, and in

Jan 1, 1886