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By Raymond M. Stateham

The Bureau of Mines has developed a portable, lightweight device for determining the integrity of resin-grouted roof bolts. The instrument functions by sending a known pulse of ulstrasonic energy into the bolt and comparing the amount of energy reflected hack with the original measured pulse. Where the bolt is properly bonded or coupled with the rock, the energy passes through the bolt-resin-rock interface and dissipates in the rock. Where the bolt is not properly coupled, the energy is reflected back along the bolt to the instrument. The ratio of reflected energy to the pulse approximates the fraction of the bolt's surface that is improperly bonded. The instrument is easy to use. The operator holds the sensor head of the device firmly over the head of the bolt to be tested, causing the pulse of ultrasonic energy to be imparted to the bolt. The device then listens for reflected energy. This cycle is repeated about 200 times per second until an evaluation of the bolt installation is made and indicated by colored lights in the display window. Bolts having 50% or less of their surface bonded are considered had and cause a red light to he illuminated. Bolts with 50% to 75% of their surface bonded cause a yellow light to be lit and are considered marginal. Bolts having more than 75% of their surface bonded are considered good and cause a green light to be lit. The indicator lamp remains on for about 4 seconds and then goes off, indicating that the instrument is ready for another test.

Jan 1, 1982

By Parsons A. E

The application of known pelletizing tech- nology was successful in the agglomeration of zinc concentrate into pellets of minus 6mm siz- ing using fine zinc calcine and sulphuric acid as binder. Subsequent roasting trials conducted in a 0.3 m diameter fluid bed reactor, showed that the pellets satisfactorily withstood hot physical abrasion during fluidization. Fines generation was low and the pellet calcine was hard, possessing excellent handling properties. Results of laboratory scale static pellet sinter- ing tests showed conclusively that the deterior- ation in sinter physical quality experienced with fine calcine was not apparent when the calcine was added to the mix in pellet form. Based on the results of small scale exper- imental work, a one tonne per hour pilot plant was constructed and operated. Several thousand tonne of pellets were produced-for fluid bed roasting in Badische Analin and Soda Fabrik (B.A.S.F.) turbulent layer (T.L.) roasters previously designed for roasting iron pyrite concentrate. Continuity of the T.L. fluid bed roasting operations was achieved when the waste heat boilers were replaced with atmospheric coolers and thus eliminated the problems of gas flow restrictions. Sinter plant trials were conducted over a period of two weeks with the addition of pellet calcine to the sinter feed. Results showed a marked improvement in sinter plant performance, and as a result of better bed permeability, increased sinter production was achieved, with- out significant deterioration in sinter quality.

Jan 1, 1974

By Wardle L, Wright G

This paper describes the investigations and results of monitoring of deformations of houses located within the area of influence of a pillar collapse over the Westfalen No. 3 coal mine near Ipswich, Queensland. The subsidence resulted in minor subsidence of at least 18 modem houses and serious damage to 4 others. The history of the events and the measures taken to deal with the physical problems arising are described. The investigations and results are described and related to the mining methods and geology. The stability of coal pillars up to 9.6 m high was considered and computer modelling undertaken to relate surface subsidence to estimates of the extent of pillar failure. Assessments were made of the likely extent of subsidence during the incident. Measurements of distortion and tilt were obtained as the ground slowly subsided and criteria established to determine when the structures were deemed to be unsafe. Detailed surveys of houses affected or anticipated to become affected were also undertaken. Four houses were condemned and subsequently demolished as a result of excessive tilt. The methods of assessment are described and the implications of the results related to the various' house designs.

Jan 1, 1992

By M. R. Khalesi, Y. Kianinia, A. Seyedhakimi, F. Soltani

"The feed ore to Agh-Darreh gold processing plant (Takab City, Iran) contains 2 ppm Au, 7 ppm Ag, and 120 ppm Hg. After cyanide leaching of the feed at pH 10.4, 80% of the total mercury (in the form of cinnabar and metacinnabar) goes to the tailings dam. In this research, separation of mercury from the tailings by flotation was investigated. The effects of collector type and dosage, pH, and the number of cleaner stages were studied. The results showed that after two stages of cleaning a 40–62% recovery of Hg at a grade of 14.3% Hg is attainable. Recycle water from a test in which 50 g/t amyl xanthate and 30 g/t pine oil was used in the flotation stage showed no adverse effect on the leaching and adsorption of gold onto activated carbon.IntroductionMercury, most commonly found in the nature as the mineral cinnabar (HgS), is a hazardous substance because of its mobility and toxicity (Kyle et al., 2012). Roasting is the wellestablished treatment method for mercury ores, in which the sulphur is burned and volatilized and mercury recovered subsequently by cooling and condensation. However, for low-grade ores, flotation is mainly applied for primary concentration due to its comparatively low costs, low environmental hazards, and flexibility regarding feed variations (Bulatovic, 2007). Particularly, cinnabar can be easily recovered by flotation using pine oil and a collector such as xanthate (Bulatovic, 2007; Crozier, 1991). Floatability of cinnabar is reduced due to surface oxidation when it is exposed to the atmosphere after crushing. This problem can be eliminated by adding copper sulphate and lead nitrate or acetate. The best pH for cinnabar flotation is in the range of 6.5 to 8.5 according to Erspamer and Wells, (1954), who reported that cinnabar and stibnite can be floated with long-chain xanthate collectors and an alcohol frother, with cumulative recoveries of 97.8% and 94.7%, respectively. Lead acetate was used as an activator."

Jan 1, 2017

By V. H. Wilhelm

The trend initiated in January 1936, of stabilized gasoline prices, increased demand and extraordinary drilling activity, continued in California during the year 1937. Crude prices were maintained during the year at the highest level since September 1930. Wildcat activity with resultant new discoveries and development of proven acreage were greater than in any year since 1928. Many fields in California in former years have been produced at full capacity, with consequent loss of reservoir energy, but at the present time continued activity is maintained to develop adequate reserves, so that production in these fields can be taken at a rate to correspond with good operating practice. Naturally, this good operating practice will be influenced to some degree by gas outlets and, in certain instances perhaps, by oil outlets. In any event, these last two controlling features will result in favorable rather than detrimental operation. In fields producing from great depths, ultimate production will be practically limited to the flowing and compressor life of the well, since there is as yet no economical method for pumping wells below depths of approximately 7000 ft. Experience has shown, however, that such pumping difficulties will be overcome and that production secured by pumping will add some to reserves established on the flowing life of the wells. California continued to operate under voluntary curtailment, but with unlimited transfers of allowable between various fields. Even though there was at all times considerable production above the Umpire's established quota, a constantly increasing demand reduced storage during the year. This increasing demand was due mainly to the rapid rise in Pacific foreign shipments from May to September. It is questionable, however, whether this favorable condition will be maintained over a prolonged period. (See Fig. 1.) Field Discoveries The great drilling activity during the year resulted in the discovery of three new fields in the San Joaquin Valley, as well as many extensions

Jan 1, 1938

HAVING previously shown you how ores are found and mined, and also how they are prepared and disposed for smelting, and then how the blast furnaces and other furnaces are made for purging their earthiness, all this would be as nothing if I did not proceed to show you the method of smelting them. Therefore, in the present chapter I wish to show you how you must proceed in this very important operation, telling you all I have seen and also how much work with this kind of blast furnace I have done or directed. For this reason I tell you first to take by weight or measure the quantity of ore that you wish to smelt and, particularly if it is a kind that contains silver, break it into small pieces about the size of [52v] beans. If the ore had previously needed evaporation by fire or cleaning by washing, you will have had this done well and have had it properly prepared by a master sorter or others. A layer of this is arranged on a bed of planks, bricks, or flat stones in front of the blast furnace and its companion is placed on top, then a quarter part of galena or a third if you can obtain it. Then an equal part of crushed iron slag or slag from the same or different ore is added. These materials are spread in layers one above the other. When the blast furnace has been constructed as taught above, correct in all its parts, and is full of well-kindled burning charcoal, then fill it up with charcoal and admit water to the bellows machine. When you see that it is well kindled again from this wind and that the flames begin to come out forcefully on top, work it down with a little rake and fill it up again. Then the pannier is filled with new charcoal, the blast furnace heaped full, and another basketful of the said composition of ore is also put on top. Proceed in this way, continually adding charcoal and ore as long as you have any, or as long as you wish to keep up the work, maintaining the blast furnace always full, or continuing in this way until the bottom of the blast furnace is filled with melted materials. Decide this by judgment, or by seeing through the mouth of the tuyère where the wind of the bellows enters that they are level with this. Then with an iron tool open the hole that was left as an outlet in front of the blast furnace and allow all the metal with its slag to run out. These two things, flowing through the chan-

Jan 1, 1942

By Daniel R. Stewart, Ralph R. Sacrison

The function of the geological engineer is to assist in mine planning and operations by collecting, interpreting, and applying geologic data to the solution of engineering problems. The geologist supports this effort by collecting additional geologic information specifically useful to the engineer. This use of geologic information reinforces the value of mine geology to the mining process beyond the traditional role of orebody definition. Work discussed includes: evaluation of caving strategies at the Climax and Henderson mines, support definition and slope stability at the Climax mine, and some uses of geology in cavability estimation for the Mount Emmons project.

Jan 1, 1992

By Harry E. Cross

Kiln Products commissioned a Waelz kiln 4 metres in diameter by 75 metres long, in South West Africa in March, 1969, to recover nine in a form suitable for the production of electrolytic zinc. The raw material consists of a mixture of zinc silicate concentrates and zinc rich tailings purchased from an adjacent zinc mine - the mixture containing 20% to 25% zinc. The chemical composition of the ore is tabulated and the initial test results are described. Due to the comparatively low temperature at which the ore starts softening the kiln has certain unusual features to enable the temperature to be controlled within the necessary limits. A detailed description of the kiln, the starting-up problems and present operating conditions and results are presented.

Jan 1, 1970

Since the discovery of coal of the Southern coalfield (Illawarra 1797, Burragorang 1806) coal mining has grown progressively to the thriving industry of today. Early shallow escarpment mining required no serious access development, but with extension of mining to further and deeper areas, sinking became necess- ary. Now, with 17 major shafts and 7 decline drifts in current use, new mining activities involve several current sinking and drifting projects, with more in prospect. Conventional sinking and drifting, using blasting and mucking techniques proven in recent years are normally in use, with attempts, recent and current to accelerate advances by boring techniques. With export and to less extent local market unpredictability, it is vital to produce mine establishment times to allow advantage to be taken of market upswings and there is great need for research and improvement of mine access construction as the major aspect of establish- ment.

Jan 1, 1976

By Yan D. S

The removal of antimony from a refractory gold-bearing stibnite ore by roasting and selective chlorinating roasting was investigated. The influence of roasting temperature, roasting time, roasting atmosphere and type and amount of chlorinating agents on antimony removal were studied. The laboratory studies carried out included roasting tests of 4 g samples in a laboratory rotary kiln, followed by 400 g samples roasted in a fluidised bed. The test results revealed that antimony was efficiently removed by roasting at temperatures over 800¦C in a nitrogen atmosphere. The most efficient volatilisation of antimony was achieved with the addition of ferric chloride at temperatures between 350-600¦C.

Jan 1, 1995

By Barnes R. G, Agostini A, Lewis P. C

The Mineral Resources Audit is a five-year Program established to produce a comprehensive and objective assessment of the mineral resources of New South Wales, including prospective resources. The goals of the Program are to improve planning and land use decision-making; attract exploration and minerals related investment; help the Department to identify and fill gaps in knowledge; and develop methods to identify and quantify resource potential and prospectivity. To achieve the goals of the Audit it is necessary to assemble and enhance a large amount of information and it is necessary to spatially analyse this information using computer-based Geographic Information Systems (GIS) which allow the collection, storage, transformation and display of large quantities of spatial data. An extensive range of both map-based and textual data can be employed in spatial analysis and resources and geoscience modelling. In order to use this information, data sets have to be corrected and standardised. Many data sets need to be classified. An objective of the Audit Program is the spatial analysis of the State, region-by-region, and the release of cleaned-up multiple digital data sets as packages which include upgraded mineral deposit information, 'seamless' geological map layers showing lithology, structures and stratigraphy, and processed and classified geophysical map layers. These regional packages are important reference sets for the mineral resources industry and will assist delineation of regional exploration targets.

Jan 1, 1995

By Fred W. Gordon

Apart from the character of pig-iron to be manufactured, other than that it shall be well reduced and open-grained, the selection of the materials should be such as to produce it at the lowest cost. As a rule, the sources of fuels and limestones are not so extensively varied as those of the ores. Many Eastern furnaces are now using Lake Superior ores, and but recently a part of the supply came from foreign ports. It is, however, of the highest importance that the character of fuels and limestones, as well as ores, should be carefully considered in determining their value and making judicious selection among those available. The formulas here offered are based upon the assumption that the heat-requirements for a given mixture are measured by a constant required by the oxide of iron, added to that required for a unit of slag, multiplied by the weight of that slag per unit of iron. The heat-requirements for oxide of iron per unit of pig-iron made are assumed to be 2854 centigrade units. This is taken from the careful analysis of Sir Lowthian Bell, and, so far as the writer is able to determine, is very nearly correct. Dividing this by the quantity of heat that may be evolved and utilized within the furnace per unit of carbon, determines the quantity of carbon required per unit of pigiron ; and if to this be added the quantity of carbon absorbed by the pig-iron, the total requirements in carbon are determined, on the assumption that pure oxide of iron is reduced with pure carbon by the ordinary process of the blast-furnace. Calculating the quantity of slag that would be made from a given mixture of ores, smelted with a given impure fuel and fluxed with a given impure limestone, multiplying this weight of slag by the heat-requirements of its unit (taken at 1050 C. H. U.), and dividing the product by the heat-units evolved and utilized within the furnace per unit of carbon, will determine the quantity of carbon required per unit of pig-iron for the slag.

Jan 1, 1893

By Artmont G. J, Palmer K

Alluvial gold is an ideal exploration tracer to bedrock source and indicator of bedrock mineralisation style because (i) gold occurs in a wide range of deposit types, (ii) primary composition is sensitive to style of mineralisation, and (iii) it is a heavy resistate mineral that is readily preserved and easily sampled. In regional exploration of the Central Ranges of Irian Jaya, alluvial gold mineralogy has been applied to maximise the information return from panned concentrate sampling and to focus exploration effort. Primary gold is a solid solution of Au+Ag¦Cu¦Hg, ¦ trace Pd, Te, and Sb. In general Ag¦Hg increase and Cu decreases with inferred decreasing temperature of formation, and gold from particular mineralisation styles has signature compositions that can be used as indicators of bedrock mineralisation type. Furthermore, the abundance of alluvial gold is an indicator of the economic potential of a catchment. The convergent continental-oceanic plate geology of the Central Ranges is conducive to a wide range of mineralisation styles. Mineralogy of gold in ophiolite, skarn, porphyry, mesothermal vein and possible VHMS environments is characterised from alluvial and bedrock samples, and the use of gold mineralogy in prospecting at regional scale through prospect definition to drilling is demonstrated.

Jan 1, 1995

By A. Beeby Thompson

FOR more than 2500 years, natural gas issues in the Surakhany district of the Apsheron peninsula were the object of pilgrimages by fire worshippers and Hindoos from Burma and India. Even as late as 1890, Hindoo priests conducted ceremonies in a temple at Surakhany, which probably replaced a more ancient one; but later, the visits of the pilgrims were prohibited in order to check the spread of Asiatic diseases in that region. For centuries, limited supplies of oil have been abstracted from shallow excavations in the Caspian oil belt and dispatched into the interior of Asia and elsewhere for medicinal and industrial purposes. Statistics show a yield of 37,400 bbl. in 1863, but only since 1869 has there been serious development; in that year the yield was 203,000 bbl. At that time, hand digging was supplanted by drilling, and the enormous wells that resulted from tapping sources hitherto beyond the reach of operators completely demoralized the industry for a time, owing to inadequate outlets for the products. The early activities in this area were greatly hindered by annoying taxation, monopolies, imperial land grants, etc., but when these were revoked or adjusted, in 1877, the industry sprang into prominence and, between 1898 and 1901, the Baku fields produced practically one-half of the world's supply of oil. Within a few miles of Baku lie the two richest oil fields in the world; viz., the Balakhany-Saboontchy-Romany and the Bibi-Eibat, the latter constituting almost a suburb of the city. For many years the gasoline obtained in the refineries of the Baku area was burned in pits, being considered an undesirable product, and until 1870 the residue also was destroyed, its value as a fuel not being recognized. Kerosene was the main product sought by the refiners. It was shipped across the Caspian Sea and up the Volga to the industrial centers of Russia. Only on the completion of the Baku-Batoum railway did the Baku oil fields secure

Jan 8, 1920

By J. C. Reed, P. J. Shenon

The Elk City district is in north-central Idaho about 60 miles east of Grangeville and near the headwaters of the South Fork of the Clearwater River (Fig. 1). At the height of its boom in the early sixties, Elk City had a population of more than 2000 people, Published estimates of the placer production from the district range from $10,000,000 to $18,500,000. Although the first quartz-vein location was made as early as 1870, very little gold was extracted from quartz ores until after the completion of the American Eagle mill in 1902. Between 1902 and 1932 a total of from $750,000 to $1,000,000 was taken from about six properties. General Geology Distribution of Rocks Banded gneiss (Fig. 2) is the most aburldant bedrock in the Elk City district. It is interbedded with schist and quartzite and ill some places these rocks have been intruded by sills and dikes. Banded gneiss prevails in the western part of the area whereas schist prevails to the southeast. Augen gneiss occurs for the most part as irregular bodies, which lie transverse to the trend of the banded gneiss and schist. It is largely confined to two areas; one of which extends from east of the American Eagle mine westward as far as the Black Pine mine, a total distance of about five miles, and another area of about two square miles in the vicinity of the California-Idaho placer mine. Quartzite is fairly abundant. In addition to the bands of the latter interbedded with gneiss and schist, some large lenses crop out in the southeastern part of the dik-trict near the southern contact of the area underlain by granodiorite. Granodiorite crops out over a large area and extends northeastward

Jan 1, 1935

By P. J. Shenon, J. C. Reed

The Elk City district is in north-central Idaho about 60 miles east of Grangeville and near the headwaters of the South Fork of the Clearwater River (Fig. 1). At the height of its boom in the early sixties, Elk City had a population of more than 2000 people, Published estimates of the placer production from the district range from $10,000,000 to $18,500,000. Although the first quartz-vein location was made as early as 1870, very little gold was extracted from quartz ores until after the completion of the American Eagle mill in 1902. Between 1902 and 1932 a total of from $750,000 to $1,000,000 was taken from about six properties. General Geology Distribution of Rocks Banded gneiss (Fig. 2) is the most aburldant bedrock in the Elk City district. It is interbedded with schist and quartzite and ill some places these rocks have been intruded by sills and dikes. Banded gneiss prevails in the western part of the area whereas schist prevails to the southeast. Augen gneiss occurs for the most part as irregular bodies, which lie transverse to the trend of the banded gneiss and schist. It is largely confined to two areas; one of which extends from east of the American Eagle mine westward as far as the Black Pine mine, a total distance of about five miles, and another area of about two square miles in the vicinity of the California-Idaho placer mine. Quartzite is fairly abundant. In addition to the bands of the latter interbedded with gneiss and schist, some large lenses crop out in the southeastern part of the dik-trict near the southern contact of the area underlain by granodiorite. Granodiorite crops out over a large area and extends northeastward

Jan 1, 1935

The Elk City district is in north-central Idaho about 60 miles east of Grangeville and near the headwaters of the South Fork of the Clearwater River (Fig. 1). At the height of its boom in the early sixties, Elk City had a population of more than 2000 people, Published estimates of the placer production from the district range from $10,000,000 to $18,500,000. Although the first quartz-vein location was made as early as 1870, very little gold was extracted from quartz ores until after the completion of the American Eagle mill in 1902. Between 1902 and 1932 a total of from $750,000 to $1,000,000 was taken from about six properties. General Geology Distribution of Rocks Banded gneiss (Fig. 2) is the most aburldant bedrock in the Elk City district. It is interbedded with schist and quartzite and ill some places these rocks have been intruded by sills and dikes. Banded gneiss prevails in the western part of the area whereas schist prevails to the southeast. Augen gneiss occurs for the most part as irregular bodies, which lie transverse to the trend of the banded gneiss and schist. It is largely confined to two areas; one of which extends from east of the American Eagle mine westward as far as the Black Pine mine, a total distance of about five miles, and another area of about two square miles in the vicinity of the California-Idaho placer mine. Quartzite is fairly abundant. In addition to the bands of the latter interbedded with gneiss and schist, some large lenses crop out in the southeastern part of the dik-trict near the southern contact of the area underlain by granodiorite. Granodiorite crops out over a large area and extends northeastward

Jan 1, 1935

By James Terry Duce

The symposium on production for the year 1940 contains few papers on the foreign situation. It is probable that the foreign part of next year's symposium will be even shorter. This is due to rigid censorship in various countries, as the question of the volume of petroleum supplies has become one of great strategic importance. This is even more true than in the last war, owing to greater mechanization of armies. 'It has always been the policy of officers in charge of the symposium to refrain from publishing information that might possibly injure national or private interests. At the close of the war we hope again to publish full and accurate records of production abroad. Excerpts from Circular to Authors In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table I may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable but not de-terminable frod data available to the author, please inserty; in spaces where the proper entries are determinable by the author, make such entries. y implies a hope that in some future year a definite figure will be available. The entry of a zero is a positive declaration, and an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In sucli cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved') and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when

Jan 1, 1941

By Kenneth Cottingham

The number of wells completed in Ohio during I940 was about 20 per cent more than during the preceding year, the comparative totals being 1020 and 1228. Of the 1940 completions, 327 were oil wells, 491 gas wells, and 410 dry. The completions for the past five years, divided into oil wells, gas wells, and dry holes, are shown in Table 2. Wells drilled deeper and input wells in water-flood areas are not included in the tabulation. The annual production of oil has decreased steadily in Ohio from the maximum of 23,941,000 bbl. produced in 1896. Table 3 shows the quantities of oil produced in the last five years. In 1940, the total was 3,052,000 bbl., produced by about 25,500 wells. The number of wells and the approximate quantities by grades are shown in Table I. Table i ,—Tabulation by Grade Grade 1 2 Barrels __________________________________________________________________________________________ Pennsylvania ............. . 1,198,000 Lima.................... . 325,000 Corning................... 3,730 1,159,000 Lodi...................... T,040 350,000 Cleveland................. 30 1:1,000 Total................... 25,500 3,052,000 The prices paid for Ohio crude oil in 1940, together with dates of changes in posting, are shown in Table 4. The production of natural gas in 0hio has declined from a maximum of 79,510,032 M cu. ft. in I9I5 S to 36,469,000 M cu. ft. in 1939, the most recent year for which a figure is available. Consumption reached its peak in Ohio in the year 1916, when it was 169,480,01r M cu. ft., declining to 114,720,ooo M CU. ft. in 1939. The produc-tion and consumption of natural gas in Ohio for the past five years are shown in Table 5. TAble 2.—Completions in Ohio during Past Five Years Numbs of Wells Drilled during Year YearI, ] Oil Gas Dry Total 1936............. 263 570 324 1,157 1937............. 317 503 45I 1,271 1938............. 189 433 288 gro 1939............. I70 501 349 1,020 19391940............. 327 491 410 1,228 Total.......... 1,266 2,498 1,822 5,586 Table 6 shows the number of oil wells and the number of gas wells completed by sands during 1940, with the average initial production per well for each sand. Table 7 shows the total number of wells drilled—oil, gas and dry—by sands. Development during 1940 Szth-Trenton.—For several years, considerahle interest has been shown in a horizon lying some 500 to 700 ft. below the top of the Trenton, known to the driller in western Ohio as the "green sand," and in eastern Ohio as the St. Peter. In 1939, ten 'lgreen sand" tests were drilled, all in western Ohio and all dry- In 19401 eight wells were drilled to this horizon, one of which was a small oil well (one barrel) in Men county- Of the remaining seven—all of which were dry-—one in Franklin County, in central Ohio, was drilled to a depth of 2903 ft. .Another was in Medina

Jan 1, 1941

By Julian M. Avery

In its dual role of pig-iron smelter and gas producer, the blast furnace is a remarkably satisfactory and efficient apparatus. Many metallurgists and engineers have pointed out, however, that since the primary function of the blast furnace is to produce pig iron at the lowest possible cost, its function as a gas producer should be subordinated to this primary purpose. During the past 10 years or more, improvements in blast-furnace technique and economy have, in fact, been directed primarily to increasing efficiency in the use of the reducing power of the gases produced by combustion of coke at the tuyeres, to reduce iron ore within the furnace. The net over-all result is a decrease in the fuel value of the top gas per unit of volume, and per ton of pig iron, which is evidently more than offset in value by the corollary saving in coke and the possibility of increased furnace capacity, for otherwise there would be no point in making such improvements. The purpose of the present paper is to suggest that, while progress has been made in this direction, there is another approach to the problem of increasing the chemical and thermal efficiency of the blast furnace in its primary role as a pig-iron smelter, which appears to offer possibilities of improvement in over-all ecorlomy of a different order of magnitude than results thus far obtained by the use of other expedients. The present argument is based in large part upon the hypothesis that the efficiency and economics of pig-iron smelting are seriously and adversely affected by the phenomenon known as "solution loss," and that the problem of solution loss call be successfully attacked by increasing the over-all pressure; i.e., the "top prcssure" under which the furnace is operated. It is indicated that pressure operation may also be expected to result in concomitant benefits, which may be summed up as generally improved operating conditions, together with a substantial saving in fuel and/or a substantial increase in furnace capacity. In a broad sense, the suggestion of pressure operation of the pig-iron blast furnace is not new, for operation under moderately increased over-all pressure was suggested as early as 1871, by no less an authority than

Jan 1, 1938