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By J. S. Miller

This paper describes the method of mining a steeply pitching anthracite seam on a heavy pitch in the Orchard vein in No. 1 Tunnel of the Lehigh Coal and Navigation Co. The Orchard vein in the Neaquehoning district has a thickness of about 15 ft. on the level of the gangway, which is sufficient thickness for the gangway to be driven full width in coal. Above the gangway, the vein becomes thinner and near the surface is about 8 it. thick. The coal is of good hard quality and carries a fairly good roof. The pitch of the vein is between 65" and 70". Usually the breast-and-pillar method has been employed in the mining of the steeply pitching veins in this section. This method produced good results as far as the mining of the breast was concerned but the recovery of the pillar was difficult as to full extraction and expensive as regards costs. To recover these pillars after the breasts were driven, three methods were commonly employed; they were known as the pillar-breast method, pillar-skipping method, and pillar-chute method. The pillar-breast method consisted in putting a battery in one corner of the pillar (Fig. I), coupling the manways A and B of the two adjacent breasts for two or three lengths ahead of the working face of the pillar being cut, and working the pillar as a breast. This method was used by the more skilled miners of the earlier days but has practically been abandoned. A slight variation of this method is used to some extent. In this case, the pillars are left wider than ordinarily and of sufficient width for the full-width breast to be driven in and a small pillar left on each side of the pillar breast between it and the regular breasts. With the completion of the "pillar breast," the ribs are drilled full of holes, loaded, and fired. In the pillar-skipping method (Fig. 2), the middle breast of three is not driven through and is drawn empty while the outside and inside breasts are kept full. At the corners of the two pillars standing, batteries are put in and a skip of the two pillars started; the coal in the two pillars is blasted over into the empty breast. A small pillar is kept along the

Jan 1, 1925

By Edwin Chance

DURING the last decade many conditions have been encountered that have materially increased the cost of the production of coal. As in most cases it has not been practicable to increase the selling price of such coal sufficiently to insure the necessary margin of profit, the mine management has been forced to avail itself of what might be termed unusual means that costs might be held at as low a figure as possible. The so-called efficiency engineer has been called upon, costly power plants have been built and machinery has been installed to replace manual labor wherever possible. Another aid used recently to secure economies through the more intelligent production of coal, is the chemist. As the coal industry, barring the production of byproduct coke, does not at once give evidence of its need of the services of the chemist, the writer will endeavor to point out a few of the services that this branch of the staff has been able to render. The preparation of coal in the past has been carried on entirely upon an empirical basis, that is, the criterion adopted has been an ocular inspection. Unfortunately, the appearance of a coal and especially of an anthracite, has but little relation to its fuel value, and as long as coal is purchased for the heat that 'can be obtained from it by its combustion, the quantity of such heat that is purchased must be one of the principal desiderata in selecting or preparing a coal. Were coals purchased for use as bric-a-brac or for exhibition in museums it might be both wise and just to purchase them upon their appearance. After 4 or 5 years of investigation the fact has been established that coals of very inferior appearance, and I now have special reference to anthracite, might and often did possess heating and burning properties superior to those possessed by, bright coals which in the past had commanded considerable and uniform premiums in the market. This being the case the question arose as to whether the trade could be convinced of this fact. While at first some difficulty was experienced in establishing the quality of such dull coals, still it was found that the real obstacle to the sale of these

Jan 4, 1916

By R. W. Smith, G. W. Delamore, J. A. Spittle

RECENT work by the authors1 has demonstrated that the crystals constituting the equiaxed zone in small ingots originate, on quenching, in the chilled liquid. Whether any partial remelting2 takes place of the den-drites nucleated in the chilled region was not examined. However, the claim3 that this normally occurs, leading to crystal multiplication, has been disputed.4 Thus, for an equiaxed zone to form in the central region of an otherwise columnar ingot, it is necessary to transport crystallites from the chill zone to this region. In view of the work of Uhlmann et al.,5 it was considered desirable to examine the transport process further. Experimental Technique and Results. In the earlier experiments by the authors.1 a stainless-steel crucible 17/8 in. diam, 41/2 in. high, ad containing an alloy of A1-4 wt pct Cu, was quenched from 660°C into a bath of Wood's metal maintained at 100°C. Under these conditions a central zone of equiaxed crystals was obtained. However, if a 2250-G unidirectional magnetic field was applied for 2 sec immediately following the instant of quenching, or subsequently, the equiaxed zone did not appear. Careful thermal analysis showed that the short application of the field had virtually no effect on the thermal conditions of the melt. It thus appeared that the crystallites which were ultimately to grow large enough to form the equiaxed zone existed in the liquid immediately ahead of the interface, occlusion being prevented by the convective fluid flow induced by freezing from the walls of the cylinder. When this relative movement was prevented by the Lorenz forces induced by the application of the magnetic field, the crystallites were caught up in the rapidly advancing dendrite solid-liquid interface. To test this assumption, a small ingot of super-purity aluminum was partially melted and poured into a heated stainless-steel mold which was then immediately quenched into molten Wood's alloy. The resulting structure is shown in Fig. 1, and consists of columnar grains with a central fine-grained zone. Thus the unmelted solid present at the beginning of solidification had been transported ahead of the columnar interface. Discussion. There appears to be little or no information available on the interaction of suspended particles with a metallic solid/liquid interface. However, some information is available for transparent organic sys-

Jan 1, 1969

By John Birkinbine

A RETROSPECT of the growth of the production of pig-iron for the past half century would be the history of the invention and introduction of heated blast as applied to the smelting of iron ores. As the apparatus employed was improved in conception and construction, the economical operation of the furnaces to which it was attached was the more marked, and the production correspondingly increased. To compare the original iron box placed over a coal fire with the modern hot-blast stove, with its combustion-chamber, gas-burners, and air-regulators, would be as unfavorable to the former as to contrast the product of the little Blauöfen with the yield of the improved furnaces of to-day. But, as these little Blauöfen were the germs from which the larger plants have grown, so from the crude apparatus invented and applied by Neilson has grown, in the face of great opposition, the more economical hot-blast stoves now in use. It is not surprising that an innovation like heated blast should have received a large amount of attention from metallurgists, nor that men of recognized ability should formerly have been found both among its champions and opponents, but it is remarkable that, at the present day, with the results of careful research and thorough experiment compiled in convenient shape for perusal, there are iron¬masters who still consider it economy to allow the products of combustion to escape into the atmosphere, rather than utilize them in heating the blast, because of a supposed injury to the quality of the product. In the present state of knowledge and practice, it is proper to express as an axiom, that a well-constructed hot-blast apparatus is essential to the economic operation of an iron-producing plant. Of the interpretation of proper construction there is of necessity a variety of opinions, and, with the view of solving the problem, the apparatus for heating blast has from time to time assumed various forms. Boxes, cylinders, and pipes, placed horizontally, vertically, inclined, or in circles and spirals, have been tried ; there have been pistol-shaped pipes, double pipes, divided or diaphragm pipes, siphon pipes, and as much variety in the mains, connections, flues, and setting. It is probable that, to the introduction of the bell and hopper in

Jan 1, 1876

C.A. MITKE, *Bisbee, Ariz. (written-discussion-? ).--The advantages of the incline-slicing system have' been ably pointed out by Mr. Scott in his paper in the November, 1917, Bulletin, and also by Mr. P. B. Scotland in the Engineering & Mining Journal, Apr. 7, 1917. From the standpoint of efficiency and economy this method is far superior to the top-slice system as generally practised. However, as regards ventilation, and the danger of mine fires, it is just as necessary to use a mechanical ventilating system in mines worked by this method as it is in those worked by the horizontal top-slice system. Mechanical ventilation not only improves working conditions in top-slice stopes but, if properly designed for the particular mine in question, permits an immediate attack to he made in the event of a mine fire with a greater degree of safety to the men. In the course of time, incline top-slicing will probably take the place of the horizontal top-slicing system just as the incline cut-and-fill has superseded the horizontal cut-and-fill stoping method. While incline top-slicing has been tried in several districts on a very limited scale with inconclusive results, the Coronado is the-only large mine at which it has yet been thoroughly tested, and there it proved to be a complete success. As Mr. Scott's figures show, the tonnage has been more than doubled, with a simultaneous reduction in costs. As has been the history with all other innovations in mining, considerable hesitation will probably be shown in introducing this method in other mines. For example, when the incline cut-and-fill system was put forward as a substitute for the horizontal cut-and-fill stoping method many mining men of good repute were doubtful of its success and post-poned its introduction as long as possible, giving as their reason certain geologic conditions which would make the incline cut-and-fill impracticable. At the present time, most of the mining companies in the South-west, who in the past had used the horizontal cut-and-fill system, have already changed over, or are in the process of changing, and have proved that in the majority of cases horizontal cut-and-fill stopes can be successfully operated under the incline cut-and-fill system. Large horizontal cut-and-fill stopes can now be found in only a few exceptional cases, and

Jan 3, 1918

By John Birkinbine

A retrospect of the growth of the production of pig-iron for the past half century would be the history of the invention and introduction of heated blast as applied to the smelting of iron ores. As the apparatus employed was improved in conception and construction, the economical operation of the furnaces to which it was attached was the more marked, and the production correspondingly increased. To compare the original iron box placed over a coal fire with the modern hot-blast stove, with its combustion-chamber, gas-burners, and air-regulators, would be as unfavorable to the former as to contrast the product of the little Blauöfen with the yield of the improved furnaces of to-day. But, as these little Blauöfen were the germs from which the larger plants have grown, so from the crude apparatus invented and applied by Neilson has grown, in the face of great opposition, the more economical hot-blast stoves now in use. It is not surprising that an innovation like heated blast should have received a large amount of attention from metallurgists, nor that men of recognized ability should formerly have been found both among its champions and opponents, but it is remarkable that, at the present day, with the results of careful research and thorough experiment compiled in convenient shape for perusal, there are ironmasters who still consider it economy to allow the products of combustion to escape into the atmosphere, rather than utilize them in heating the blast, because of a supposed injury to the quality of the product. In the present state of knowledge and practice, it is proper to express as an axiom, that a well-constructed hot-blast apparatus is essential to the economic operation of an iron-producing plant. Of the interpretation of proper construction there is of necessity a variety of opinions, and, with the view of solving the problem, the apparatus for heating blast has from time to time assumed various forms. Boxes, cylinders, and pipes, placed horizontally, vertically, inclined, or in circles and spirals, have been tried; there have been pistol-shaped pipes, double pipes, divided or diaphragm pipes, siphon pipes, and as much variety in the mains, connections, flues, and setting. It is probable that, to the introduction of the bell and hopper in

R. B. BrinSmade, Ixmiquilpan, Hgo., Mexico (written discussion*).—While agreeing with Mr. Gibson that his net-profit tax is the fairest and best for mines, I believe that the tax he describes can be more accurately defined by another name. In accounting, net profits are usually considered to be the residual of the gross income after operating expenses and the annual charge for upkeep of plant have been deducted. Even the necessary interest on bonds or mortgages should not be subtracted in this calculation, for this interest represents merely that fixed portion of the net profits going as a return to that fraction of the total property value owned by the bondholders. Applying this method of calculation to the gross income of a mining property, we should onIy deduct operation expenses and upkeep of plant to get the net profits on its whole property value. So Mr. Gibson in deducting a further sum, to cover the interest and amortization of the capital expended in mine development and equipment, really arrives at something quite differen't from net profits; which can properly only be defined as the annual value of the mineral in the ground, or the royalty value in miners' parlance. From one viewpoint, Mr. Gibson's first principle, which assesses taxes, "proportionate to the benefits received by the person or property taxed," is identical with his third principle wbich assesses "with reference to the extent and value of the natural resources enjoyed." With one exception, everything of use around a mine represents a cash expenditure, or its equivalent in human labor, and state action has not added an iota to its value. The one exception is what makes the enterprise possible and it includes the mineral deposits and their associated surface; water and other landed rights. These natural resources are origin2!1y the gift of tile people acting through their agent, the state, and it is evident that a tax laid on whatever profits may arise from their enjoyment will be exactly "proportionate to the benefits received by the person or property taxed." Mr. Gibson is mistaken in his belief that the general property tax of the United States has the same incidence as his system of taxing profits, because the general property tax falls not only on land1 value—as does

Jan 1, 1920

By Max Roesler

W. L. CUMINGS,* Bethlehem, Pa. (communication to the Secretary+). -In this discussion of Mr. Roesler's paper, I shall follow Kemp in using the term "granite" to refer to the acid rock called syenite by Kimball. Diorite, as I understand it, is the dark basic rock invariably closely associated with the orebodies. The types of rock of intermediate composition, mainly intrusives, are not under discussion. It is difficult for me to conceive that this granite is the ore-bearing agent, for the following reasons: 1. No isolated orebodies in the granite are known. It would seem that if this rock is the mineralizer, some small bodies, or at least patches and small masses of ore so situated would exist. 2. In 1909 the writer conducted explorations on the Pequena and Grande claims about 1 mile north of West Mine No. 5. This work was done after a very careful magnetic survey had shown a large and uniform area of attraction. As exploration progressed, it became evident that in this case the magnetic attraction was due to disseminated magnetite. Much ore of 40 per cent. Fe was found, but very little commercial ore was shown up. This ore was entirely in the diorite and no granite outcrops are near. The occurrence could easily have been described as "ore formation but very little ore." I cannot conceive how a remote granite intrusion could impregnate a diorite mountain with 40 per cent. of Fe, and prefer to believe that this 40 per cent. of iron was in its real home, rather than in a sort of dioritic "boarding house" after having been evicted by granitic parents. 3. The Ocaña mine, which has produced nearly 500,000 tons, shows no evidence that the granite is the mineralizer. This is admitted by Mr. Roesler on p. 1827. 4. I believe it will not be disputed that all the iron-ore deposits extending along the south coast for 60 or 70 miles are of a similar origin. Evidence available at other points might properly be referred to in discussing the article under review. At the La Plata mines, about 60 miles west of Santiago, the writer has also made explorations. No granite is in evidence. At one point in the bed of a creek is a small body of magnetite about 10 ft. long, entirely surrounded by a hard fresh diorite. To me

Jan 3, 1917

By J. J. Frawley, W. J. Childs

PREVIOUS studies have shown that if a supercooled liquid metal was perturbed by vibration the probability of nucleation is is During a recent investi- gation to determine quantitatively the amount of energy needed to cause nucleation in a given supercooled liquid specimen, it was found that at low-energy values in the megacycle range, below the threshold energy value for cavitation, the amount of dynamic supercooling was greater than the amount of static supercooling. That is, if a specimen had a given amount of thermal supercooling under static conditions, its thermal supercooling could be increased by the addition of low-energy sound waves. The material used in this investigation was high-purity bismuth. This material was chosen because of its low melting point and the high degree of supercooling which could be easily obtained. The sound gener- ator employed in this work was a commercially built Sperry ultrasonic testing unit. This unit was equipped with a barium titanate crystal as a piezoelectric transducer. These sound waves were transmitted to the supercooled melt by a Pyrex rod, as shown in Fig. 1. The transducer was coupled to this Pyrex rod wave carrier by motor oil. The Pyrex wave carrier was approximately 1.5 ft long to prevent damage to the transducer by heat. The diameter of the Pyrex wave carrier appears to be critical. In the initial tests a wave carrier of 0.5 in. in diam was employed. However, the sound waves had no effect on the amount of dynamic supercooling. When the diameter of the wave carrier was increased to approximately the inside diameter of the Pyrex crucible, the sound waves were more effective. Approximately 200 g of metal was melted under a stannous chloride flux in a 30-ml beaker by induction heating. The temperature was recorded by a Pyrex-encapsulated chromel-alumel thermocoule which was placed in the beaker after the bismuth melted. The Pyrex wave carrier was immersed slightly below the surface of the liquid bismuth and the specimen was reheated to about 500°C. It was observed that the amount of supercooling depends on the amount of superheating the specimen receives; therefore, for meaningful results the amount of superheating was the same for all heating cycles. The specimen was allowed to cool in air and the change in temperature was continuously monitored with a potentiometric strip-chart recorder.

Jan 1, 1969

By J. N. Houser

THE industrial relations between the Tennessee Copper Co. and its employees have developed a number of interesting things and have been most, profitable to the employees and to the company. It is noteworthy that considerable has been done without a formal organization of any kind built up through the efforts of the company. From time to time there have been discussions regarding the advisability of a formal organization and the decision has always been in favor of the present method. In the year 1919, the company was dealing with its employees through union committees and, after an understanding was reached, satisfactory results began to be obtained, but as time went on the committees did not function and it came to a question of how to reach the men. For the past two years, about once a month, but at no stated time, there has been a meeting with a committee of employees consisting of 40 or 50 men out of 700. This committee is secured by notify-ing the locals. In addition, the Service Department notifies a number of men not represented in the union, so as to have a large representative committee. The meetings are on company time and the men are rotated, so that in time every employee attends , at least one meeting. All department heads and a number of foremen also are present. The operating plans and policy of the company are set out at the meetings and the market outlook for products is discussed. Explana-tions are also given of anything that has come up since the last meeting which affects the employees, and an effort is made to inform them of what will probably happen in the next month or two. Once a week there is a meeting of department heads with the manager, for discussion of all operations as a whole and such depart-mental details as seem advisable. When the depression started, it was necessary to curtail operations and the reasons were carefully explained; before the men were laid off, the employees as a whole were advised of the coming layoffs through these meetings. They were also advised generally who would be retained and given an opportunity to express their agreement or their. disapproval. In fact, an effort was and is being made to keep the employees advised in advance of matters affecting them and to give them full opportunity to express themselves.

Jan 12, 1922

By I. I. Gardescu

Rumania produced during 1936 some 62,500,000 bbl. of oil. Of this production, 99 per cent comes from an area running east and west along the southern foothills of the Carpathian Mountains just north of Bucharest. This almost rectangular area measures 20 by 40 miles and is located in the districts of Dambovita and Prahova between the cities of Targovigte to the west and Mizil to the east. The remainder of the production is about evenly divided between the oil fields north and east of Mizil in the Buzh district and those to the north on the eastern flanks of the Carpathian Mountains in the district of Baciiu. The Transylvanian Basin to the north and west of the Carpathian Mountains has produced to date only dry gas from its numerous salt domes. Bucsani Field The Bucgani oil field produced 15,600,000 bbl., or 25 per cent of the total production of Rumania in 1936. Bucgani is a deep-seated salt dome 7 miles south of the old Moreni oil field. A slight surface doming, not dissimilar to the topography observed on some of the oil fields of the Californian basin, called attention to the area. It is the southernmost oil field and, together with the deep-seated and prolific Boldesti field, points to the great oil possibilities of the deep-seated domes along the northern edge of the Rumanian plains south of the Carpathian foothills. The Government is the principal owner of the oil and gas subsurface rights in the areas south of the foothills. The acquisition of leases by the operating oil companies may be made either by application for an exploration permit, the company being assigned part of the acreage in case of successful wildcatting, or, if the area has already been declared as proven territory, through competitive bidding. A block of 164 acres was auctioned recently for $200,000, or $1200 per acre. The largest producer in the Bucgani oil field is the Steaua Romana, which produced 39.5 per cent of the total for the field. The Steaua Romana is a post-war company and 50 per cent of its shares are owned by the British Steaua and the Steaua Franpaise and the other 50 per cent by a group of Rumanian banks and by the Government. The Colombia,

Jan 1, 1937

By W. H. Eardley

IT IS increasingly evident that the excellence of blast-furnace operation to a great extent depends upon the preparation of the products fed into the furnace. The preparation of these products is carried on largely in the roasting and sintering departments. Prior to the building of flotation plants in Utah and other western states for the treatment of lead-zinc ores, the gravity concentrates received at the Midvale smelter amounted to about 4000 tons per month, containing 24 per cent. lead and 10 or 11 per cent. zinc. This product was about 20 mesh-that is, 45 per cent. of it would be plus 20 mesh and the balance minus 20 mesh. About 1000 tons of pyrite per month, containing 5 per cent. lead and 10 per cent. zinc, was also received. These products were sent to the multiple-hearth roasters for calcining, after which they were sent to the Dwight-Lloyd machines for sintering with other ores. The sintering charge passed over the machines but once. The first flotation products received consisted of a wet, sticky, muddy mass, containing a large amount of moisture, up to 19 or 20 per cent., and it was almost impossible to feed .them with any degree of regularity, if at all, through our standard feeders; but the amount of flotation product received during the first year or so was relatively small and it virtually lost its identity by being mixed with a large amount of jig and table concentrates. As the quantity of flotation products increased, more efficient filtering was accomplished and the moisture greatly reduced. FLOTATION PRODUCTS RECEIVED At the present time the Midvale plant receives about 4300 tons per month of flotation product running 60 per cent. lead and 4.5 per cent. zinc, 85 per cent. of which is minus 200 mesh and contains about 8 per cent. moisture; and 4000 tons per month of pyrite of similar fineness, running about 2 per cent. lead and 3.5 per cent. zinc, containing about 10 per cent. moisture. The lower moisture greatly reduces the difficulties of handling, making it possible to run a 100 per cent. flotation feed on a multiple-hearth furnace without serious mechanical troubles. The calcine, however, would contain-nodules and balls of unroasted concentrates, sulfur elimination

Jan 1, 1928

By B. D. Cullity, J. T. Norton, M. Telkes

M. Balicki—As one who some years ago spent much time searching for an alloy with high thermoelectric power that would be suitable for heat energy-electric energy converter based on the principle of a thermoelectric pile, I would like to make a few comments touching upon that aspect of this excellent paper. The specifications which one of the authors has formulated so aptly do not appear to me as complete, and I would like to add to them the following two demands: (1) Melting point not less than 500°C and (2) elongation on 2 in. at least 5 pct. Condition 1 would insure good thermodynamic efficiency of the pile by permitting a reasonably high temperature of the hot junction and at the same time making it suitable for such application as salvage of vast amounts of energy which is lost in the form of sensible heat of waste gas leaving industrial and other furnaces. Condition 2 is also a very important one; particularly, because of the fact that all elements and alloys which exhibit attractive thermoelectric properties seem to be as a rule very brittle. The design, erection, and maintenance of a pile incorporating a brittle material in one of the most crucial parts of the converter would be a very difficult and costly affair indeed. To illustrate this point I may mention great difficulties I encountered when trying to make thermocouples of silicon. Casting of 1/4-in. rods in iron or graphite mould yielded only broken pieces which had to be welded into a bar. Such a bar had to be handled very carefully during the determinations. Raising the molten silicon by vacuum into a silica tube and solidifying it there solved the problem of stability as well as that of electrical insulation of a bar. On tests this bar (98.5 pct Si) showed dE/dT = — 275.5 microvolts per degree C vs. copper. Thermocouples made of this grade of silicon and pure nickel developed 0.39 v when temperature of the hot junction was approximately 1000°C. The possibility Dr. Gonser has mentioned of trying to impart to metals good thermoelectric properties by alloying them with silicon, has been considered. The preliminary survey which I have made was, however, disappointing. Perhaps, it will be advisable to record the results obtained (table VI), as this might save repetition of search in fields already covered.

Jan 1, 1951

By Casimir Constable

DURING the years 1875 to 1879 I had charge of the Rockwood furnaces and mines, situated forty miles from the nearest railway communication at that time, and one hundred miles north of Chap tanooga, Tenn., by the Tennessee River. The small furnace with old-fashioned stoves, then in blast, was built under great difficulties by General Wilder. The early conditions were somewhat as follows: The ore was fossil ore of the Clinton group ; very fine and generally wet, without other admixture. The coke had a large amount of ash, and the fur" nace appeared to be badly scaffolded at times. On many days only a few tons of iron could be obtained. The founder generally id creased the revolutions of the engine when signs of chilling appeared,. The cinder at such times was black, very scoriatious, often closely resembling mill cinder. When the pressure was increased (the joints being the old-fashioned rust joints), leaks in the blast-pipe occurred It was noted that when the blast was stopped, and the leak bolt imperfectly remedied, the furnace improved a little. This set me thinking on the right track; and I took the responsibility of be coming my own founder for a time. A scaffolded condition had existed, and the situation was a trying one. Strange to say the negroes proved excellent furnace-men. Conceiving the hearth of the furnace to be similar to the grate area of a steam-boiler, capable of disposing of but so much fuel per hour, and requiring only a corresponding amount of air, it follows that an excess of air will burn the fuel not yet arrived at the hearth!, and raise the melting-point far above the tuyeres. This might pro duce scaffolding or at any rate choke the boshes, and leave less fuel to be consumed in the hearth. Thus for the time being less ail;. would be needed, as the continued burning of fuel in and above the boshes, would only aggravate the trouble. This condition of affairs accounted for the black cinder; the heat above having melted ore not yet perfectly reduced. This view decided me to reduce the revolutions of the engine; thefurnace finally became gray, as might have been expected. Any attempt to increase the speed produced black cinder and hard iron ;

Jan 1, 1883

By Jesse O. Betterton

In the Parkes process of lead refining, after desilverization has been completed by means of zinc additions, there will remain in the lead from 0.5 to 0.6 per cent zinc. At this stage in the refining practically all impurities are reduced to refined lead specifications except zinc and antimony. All excess of copper and nearly all the arsenic goes out with the silver. Silver remaining should not exceed 0.1 oz. per ton. It thus remains only to remove zinc and antimony to produce refined lead. The older practice was to complete refining by means of oxidation processes in reverberatory furnaces. Essentially this consisted of heating the lead to 1200' to 1300" I?. and allowing it to come in contact with a considerable excess of air passing through the furnace, or accomplish the same result by blowing the lead with steam by means of pipes introduced for that purpose, at the same time allowing air to enter the furnace. Usually some procedure involving alternate oxidation and reduction with fine coal or coke was employed in order to reduce the weight of dross or skim finally removed from the furnace. This practice had many elements of weakness in that the main flour of lead, after the preceding expensive operations had been performed, and the whole refining process nearly completed, was subjected to an operation at a comparatively high temperature, which involved much lead loss if the furnaces were not on bags, and the production of 3 to 5 per cent of the weight of the lead as dross or skim, which had to be resmelted and the lead either refined or produced as antimonial lead. In addition, the operating expense of the process was a considerable item. The process of dezincing with chlorine was developed as a substitute for the foregoing described oxidation process, and finally resulted in such advantages as nearly equal operating costs, a practical elimination of the lead loss, and the direct production of a very valuable byproduct, zinc chloride, that may be sold as such or retreated for its zinc and chlorine contents, both of which can be reused in the refining processes. Essentially this process consists of circulating the lead by means of a pump in a kettle through a closed reaction cylinder, gaseous chlorine entering the reaction cylinder with the stream of lead from the pump. Molten zinc chloride is thus produced and is discharged together with

Jan 1, 1937

By Olav Klomstadlien

The lean, but extensive iron ore deposits of the Dunderland Valley north of Mo i Rana, Norway, are the raw material base for Rana Mines, a division of the state-owned A/S Norsk Jernverk steel mill. The iron bearing minerals are magnetite and specular hematite. The magnetite/hematite ratio varies considerably both within each deposit and from one deposit to another. The ore bodies that lend themselves to mining have generally a thickness of 30-60 m grading 30-35% Fe and 0.15-0.25% P. The grain size varies from 0.05 to 2.5 mm. The fine grained ores are hard while the coarse grained ores are soft and easy to grind. The A/S Norsk Jernverk steel mill operates both a sinter and a pellet plant, and this necessitates production of two types of concentrates. The present flowsheet is shown in [Fig. 1]. The crude ore from the pits is crushed in a 1.07-m gyratory crusher with an open side setting of 12.7 cm. The crusher product is transported by rail to the concentrator located 25 km from the mines. The ore is fed by twelve 1.22 X 1.83 m vibratory feeders onto conveyor belts which carry the ore to a surge bin ahead of the autogenous mills. The feed rate is automatically adjusted to maintain a set power load at a level suitable for the ore type being processed. The mills operate in closed circuit with twelve dual-drum screens equipped with a 0.8-mm screen cloth. Oversize is returned by gravity to the mill feed while undersize flows to the gravity separation section which consists of Humphrey spirals in three stages. The ores are very heterogenous and analysis may vary quite considerably. The quantitative need for concentrate in the steel mill may also change rapidly. The process in the concentrator must therefore be easily changed, and consequently alternative process lines have been established. This is indicated with the dotted lines in the flowsheet. Apatite is removed by flotation by fatty acids to give a final sinter concentrate of 63% Fe and 0.020% P or less. Pellet concentrate contains about 65% Fe and less than 0.020% P. The fineness is about 1500 Blain.

Jan 1, 1981

By Lewis A. Riley

I desire to submit, for the consideration and information of the members of the Institute, the following data, drawings, and tables, showing what I believe will be interesting information with regard to the diamond drill, and its uses in developing mineral lands. I would first say that the results given have been obtained during the past two years by means of two drilling machines belonging to the Lehigh Valley Coal Company, operating on their coal lands in the Mahanoy, Lehigh, and Wyoming regions. 1st. A tabulated statement, giving location of borings, date, progress, total cost, itemized cost per foot, etc. 2d. Section showing strata bored in Nos. 5 and 10 holes at Mt. Carmel, see Plate VI. 3d. Section showing strata bored in No. 19 hole at Hazleton, see Plate VI. 4th. Photograph and description of drill No. 2. From the first it will be seen that the total number of test-holes bored up to May 1st of this year is 24; 9 of these are in the Mahanoy region, 6 in the Lehigh region, and 10 in the Wyoming region, in all of which cores have been taken for the whole distance. The total distance bored is 9902 feet. The majority of the holes have been put down for the purpose of proving the lower veins of the coal series, and have had to encounter the harder rocks of the coal formation. Much of the distance has been through the lower conglomerates, going in some cases through the coarse egg conglomerate, the foundation of the coal deposit, and to the green sandstone and red shale which underlie it. These lower sandrocks and conglomerates are among the hardest known to geologists, and present a formidable resistance to the exploring drill. This fact must be taken into consideratiotl in comparisons of cost of drilling, and when considered will still further improve the very favorable results I am able to show in my statement of costs. In illustration, I will cite the work of one bit when boring in the upper or softer rocks of the Wyoming region, where 280 feet were obtained without resetting, while in the Lehigh and Mahanoy regions, in the lower and harder rocks, bits set with the same quality of diamonds would only bore from 3 to 20 feet before being worn out. In this connection it may

By Daniel M. Bass, Paul B. Crawford

Laboratory investigations have been made to study the effect of variations in fluid characteristics, gas saturation, water saturation, and water injection rate on oil recovery by water flooding. Three synthetic gas-saturated crude oils having bubble points of 860, 1,540 and 1,885 psi were used as reservoir fluids. Repeated tests were made in which a and pack, saturated with water and synthetic oil, was produced by solution gas drive followed by water flooding at various pressure levels. Oil recovery by solution gas drive and subsequent water injection is shown to vary with the pressure and rate at which the water flood is conducted. The pressure at which optimum flooding conditions exist is shown to be a functiotl of the physical characteristics of the reservoir fluid. For the systems studied, increases in oil recoveries of near 10 per cent were obtained by flooding at the most desirable conditions. Va- riations in initial water saturations gave results similar to those in the literature. INTRODUCTION Most of the waterflooding studies investigating means of improving present exploitation processes have been conducted at low pressures with little effort to simulate reservoir conditions. Holmgren and Morse' performed a waterflooding study at 300 to 500 psi wherein the gas saturation was created by injecting gas, letting dissolved gas evolve from the oil, and then flushing the core with "live" oil until the desired gas saturation was obtained. Their results show increasing oil recoveries with increasing gas saturations. Data presented by Guerrero' and Kennedy, et al, indicate that in some instances water flooding at approximately 500 psi below the original bubble point results in a lower residual oil saturation than is obtained when water flooding above the bubble point. In their work gas saturations were created by primary depletion. By correcting low pressure flooding data for fluid shrinkage, Dyes found that a maximum oil recovery may be obtained by flooding with initial gas saturations of from 7 to 12 per cent. The purpose of this work was to determine the variations in oil recovery caused by initiating a waterflooding program at various stages of primary depletion of a core. This is a part of a more comprehensive study of obtaining criteria for determining when to initiate a pressure maintenance program and what fluids to in-ject. EQUIPMENT A schematic diagram of the apparatus is shown in Fig. 1. Fluid transfer was accomplished with metering pumps. Pressure control was ob-

Jan 1, 1957

By Cornelius Kelley

I HAVE been asked to discuss "What Can be Done to Revive the Mining Industry," particularly from the standpoint of the copper industry. It is impossible to consider this problem, if in fact there can be one, from an isolated position. The mining industry is but a part, although a very important one, of that exceedingly complicated machine characterized as commerce, which comprises within its operation and functions the-multitudinous activities that, combined, make up the sum total of the production, manufacture, distribution, sale and utilization of goods and products resulting from the agrarian, industrial and commercial effort of mankind. We survey a world today with its disturbed mass of humanity permeated with discontent, passions loosened by brutal combat not yet brought under control, class hatreds aroused, national prejudices in a state of stimu-lated excitement, governments for the most part enfeebled, some destroyed to their foundations, with fragile structures raised in place of those that seemed enduring, and which have disappeared. A burden of indebtedness incurred in defiance of all economic law exists, to meet the exactions of which, levies of taxation that constitute a grievous burden upon effort and industry are exacted by the needs of those nations that are most favored, while printing presses are busy manufacturing currency that either has, or approaches, a negative value among those less favored. This picture, while not pleasant, is one that should be looked at squarely and carefully appraised in estimating the immediate future. For four years the world marshalled, and exerted without stint, its combined endurance, vitality and resource in an effort of destruction, which violated no less the orderly working of physical and economic laws than it did the conventions of social and civic relations. To have imagined that without travail the orderly processes that governed the relations of mankind could at once be reestablished and begin functioning, was, as has been demonstrated, fallacious; perhaps no more so than the error that is committed today by those opportunists who fail to take cogni-zance of basic conditions which must be remedied be-fore the world can resume its progress to a universally prosperous and satisfactory condition. Please do not gather from this somewhat unpleasant recital that I regard the future with gloomy foreboding or entertain pessimistic doubts, for, emphatically, I do not.

Jan 2, 1922

By W. W. Weigel

THE mines of the St. Joseph Lead Co. in St. Francois County, Missouri, form a roughly triangular area of about 45 square miles. Locally this is known as the Lead Belt. The four operating mines in the area at present are the Federal, Leadwood, Desloge, and Bonne Terre, in decreasing order of mine area and daily production. Mining began in 1864 and has been carried on in the district continuously since that time. [ ] As a group, the Lead Belt mines now handle 20,000 gal. per min. of water, average head about 465 ft., against a normal daily ore tonnage of 21,200 tons. For a six-day operating week this gives a ratio of 6 ½ tons of water per ton of ore. Total average pumping in 1931 was about 15,000 gal. per min. Since that time a large area of virgin territory has been opened, much of which has had temporary flush flows. About 75 per cent of the water enters in certain restricted very wet areas. Production figures are given in Table I. The figures by divisions for 1931 and 1941 are not exactly comparable, as there were several transfers of pumping loads from one division to another during that period of time. GEOLOGY The basement formation in the Lead Belt area consists of the pre-Cambrian rhyolite porphyry and granite. Overlying this is the La Motte sandstone, of Middle Cambrian age, which offers a good medium for circulation of water. It varies in thickness up to 400 ft. Above this is the Bonne Terre dolomite, approximately 375 ft. thick, which in turn is overlain by the 150-ft. Davis shale. The formations above this, present in the Lead Belt in small areas only, are of minor importance. The ore bodies occur as large, horizontal tabular masses or as long, narrow runs; they are found throughout the Bonne Terre but largely in the lower 150 ft. The rather indefinite contact with the La Motte is a favorite ore horizon. Mining is entirely by open stope and pillar breast systems. To the south, west, and north of the district, sandstone outcrops are few and limited. Heavy faulting bounds the district on those sides and probably there is little if any artesian circulation from those directions. To the east, the La Motte rises to an outcrop area of about 40 square

Jan 1, 1943