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By R. T. Mishler

I wish to express my keen appreciation of the article on the above subject by Coe and C1evenger.l It has been doubly interesting to me, for the reason that the experience recorded and the principles evolved practically parallel the results of similar investigations made by myself and others at The Lucky Tiger Mine, El Tigre, Sonora, Mex. An outline of the work at El Tigre may aid in confirming the principles expressed by Coe and Clevenger. El Tigre has the unenviable distinction of possessing a slime with a much lower settling rate than any recorded in the article discussed. Under most favorable conditions the settling rate is about one-third that reported for the Liberty Bell mill, and one-tenth that reported for the Nipissing, Golden Cycle, and Presidio mills. This slow settling characteristic of Tigre ore has necessitated careful investigation of settling phenomena throughout the various evolutions of the plant. Previous Settling Investigation at Tigre During construction work at the mill, the metallurgical engineer in charge, D. L. H. Forbes, ran a series of experiments on settling. His tests proved that deep settling tanks were not ordinarily necessary. The use of tanks 2 or 3 ft. in depth was suggested.2 Later experiments demonstrated that the following principles of settling applied to Tigre pulp.3 1. In settling dilute pulp, settling rates are independent of pulp depth. 2. In settling thick pulp, settling rates are approximately proportional to pulp depth.4

Jan 1, 1918

By Wilhelm Borchers

In all special branches of the chemical and metallurgical industries, in which large electric furnaces became necessary for carrying out new processes or for the improvement of old ones, the development of the electric furnaces took place on much the same lines. The endeavors to make a success of a new idea brought forth many ingenious designs, which, however, almost without exception, furnished the proof that the safest and shortest way to practical success is the utmost simplicity of construction of the necessary apparatus. Our knowledge of the qualities of materials for building electric furnaces and of the constituents of the furnace-charges, especially their electric conductivity and their chemical affinity towards one another at high temperatures, is still far from being complete, and from this fact we must conclude that the smaller the number of elements in the construction of a furnace, the fewer the number of unreliable factors both in the construction and in the operation of the electric furnace. This conclusion deserves special attention when an electric furnace for making steel has to be chosen from the constantly-growing number of inventions, inasmuch as the chief constituent of steel, the element iron, is a substance which in its liquid phase has so great an affinity for those elemen'ts which are to be removed from the charge, that it is very difficult to comply with the following conditions: 1, to heat the refining-slag to the highest point of its chemical activity ; 2, to prevent the iron from entering the slag, or, where this cannot be done, to make it enter so that it finally appears in the end-product

Jan 1, 1911

By L. A. Delano

During 1916, the St. Joseph Lead Co. milled 2,505,670 tons of ore. This is a daily operating average of 7855 tons. The economic concentration of such a large tonnage necessarily requires a plant equipped with modern machinery and operated efficiently. The milling process used in producing this output has been a gradual development through the long period of years that the company has been in existence. HISTORICAL SUMMARY OF MILLING PRACTICE Ore was first mined at Bonne Terre, Mo., in 1864. The early milling practice was crude. It consisted of breaking the ore into small pieces by hand, pulverizing in a Blake crusher and a pair of Cornish rolls to approximately minus 6 mm., and jigging in the old-fashioned hand jigs. Only the coarse heavy galena was saved, the gangue being shoveled off and discarded. The output for the first year under this method was only 240 tons of pig lead. The first mill of the company was a combination of extensions and additions built from time to time as the mines developed. It was a museum of early milling machinery, such as jigs, percussion tables, buddies, dolly tubs, log washers, etc., following no definite flow sheet. The chats, or tailings, were hauled to waste dumps by mule and ox teams, as much as 500 tons per day being moved in this manner, until a railroad was built in 1880. This mill was burned in 1883, at which time the annual output had reached approximately 7300 tons of pig lead. A new mill of 500 tons capacity was designed and built by C. B. Parsons. This mill has been admirably described by H. S. Munroe.' The ore was crushed in Blake crushers, Cornish rolls, through 6-mm. screens, and treated by jigs of the Parsons type, percussion tables and log washers, or trunking machines, for cleaning the galena. The middlings were recrushed in rolls and treated on Harz jigs. The mill was operated without change, except later installing Gates crushers and en-

Jan 1, 1918

By Charles N. Bell

The Telluride mining district of southwestern Colorado is defined by the 37" 45' and 38" parallels of latitude and 107" 45' and 108" meridians of longitude. Telluride was never a boom camp, but has had a steady growth. In recent years, notwithstanding the business depression of 1920, the business has been the same as in normal years. The first prospector is said to have appeared in 1875, in which year locations on the Smuggler vein were made. Shipments were made in 1877 and 1878, and in 1879 milling the ores was attempted. While the district produced high-grade ores, it did not become important until 1890, when the Rio Grande Southern R. R. was completed from Ridgway to Telluride. The railroad has since been extended to Durango. In the fall of 1896, 400 stamps were in operation, and the annual production was $3,000,000.00, two-thirds of which was gold. The total production from 1875 to 1923 was: gold $58,274,527; silver 41,-830,920 oz., valued at $31,016,893; copper 15,258,866 lb., valued at $2,533,291; lead 166,056,484 Ib., valued at $8,324,910; zinc 18,141,182 Ib. valued at $1,323,787; or a total production of $101,473,408. All claims are held in fee. Most of them are 1500 by 300 ft. but claims located within the last few years are 1500 by 600 ft. General supplies are obtained at Telluride, Denver, and Salt Lake. The largest mines are within 6 miles of the town of Telluride. Denver is 422 miles and Salt Lake is 439 miles, by rail, from Telluride. One-half of the distance to Denver and one-sixth of the distance from Telluride to Salt Lake is by narrow-gage railroad. The labor is efficient. The best miners are Italians and Austrians, then Slavs, Greeks, and Mexicans follow in the order mentioned. There are no labor unions. There are no serious mine pumping problems, the drainage being through adits. The Tomboy and Smuggler companies pump water from their reservoirs, the former for milling and domestic purposes and the latter for milling, power, and domestic purposes. BIBLIOGRAPHY A partial bibliography of the Telluride District is: Geologic Atlas Telluride No. 57; Preliminary Report on the Mining Industries of the

Jan 1, 1925

By Keith Sutherland

AEROFLOAT 25 is a complex mixture of free cresylic acid with aryl substituted dithiophosphoric acids, sulphides, disulphides, etc. Its complete composition has not been published by the makers or patentees. It is prepared1 by the reaction between phosphorus pentasulphide and carefully selected cresylic acid. We have been informed that this acid contains no phenol and very little cresol, and that it is rich in the higher alkyl phenols, particularly the xylenols. The reaction between a phenol ROH and phosphorus pentasulphide may produce compounds of the following type:2 (i) RO S P Diaryldithiophosphoric acids RO SH (ii) R-SH Thiophenolic compounds (iii) R-S-R Diaryl sulphides (iv) R-S-S-R Diaryl disulphides (v) Substituted thianthren compounds Except for the simplest type, the thiophenols (ii), the boiling points of these compounds lie above 300° C. The amounts of the thianthren compounds formed from the five xylenols (if all these are present) will vary according to the position of the substituents. In an attempt to ascertain something of the nature of the reagent, fractional distillation under atmospheric pressure was undertaken. At the outset, hydrogen sulphide was freely evolved, and-particularly below 200° C.-the fractions had the strong odor characteristic of the

Jan 1, 1939

Discussion of the paper of L. C. Graton and Joseph Murdoch, presented at the New York Meeting, February, 1913, and printed in Bulletin No. 77, May, 1913, pp. 741 to 797. THOMAS T. READ, New York, N. Y. (communication to the Secretary *) :-At the meetings of English technical societies it not infrequently happens that, during the discussion of a paper, someone will arise to say that although he highly appreciated the material presented, nevertheless he believed it would have been better if some other phase of the question had been more highly emphasized. Assuming that this form of discussion is permissible in the Institute, I should like to reiterate the point made by Prof. A. J. Moses that conclusive proof of the identity of the minerals in question is an essential feature of the study of ores in this way. This is also expressed by Paul Krusch in his recent valuable paper 1 on the sulphide ores (in which he arrives at conclusions diametrically opposed to those of Mr. Graton), as follows : ?The diagnostic properties of the various ore minerals are known to but a limited circle of investigators." Many earlier investigators began the study of ores beneath the microscope by reflected light, but discontinued their work, in most cases, because they were unwilling to undertake the great amount of preliminary work necessary to securely establish a basis for their inferences. It is evident that Messrs. Graton and Murdoch realize that the promised later paper on diagnostic characters will be the more important of the two, but the point should be emphasized to forestall a flood of literature from other investigators who may gain the impression that the brief survey of polished specimens is a wade mecum to incontrovertible conclusions as to any given ore deposit.

Jan 10, 1913

By R. J. Piros, Brusenback, D. A. Dahlstrom

DEWATERING fine coal has been a serious problem to many operators who desired to wet-wash finer sizes and maintain high recovery. Centrifugal driers have become popular for this purpose for sizes between 3/8 in. and 14 mesh. Below 14 mesh the perforated screen centrifuges lose a large per- cent in the effluent solid bowl types that do retain -14 mesh coal, produce excessive degradation, tend to retain the highest ash fraction in any size fraction, and are subject to abrasion, which results in higher maintenance. In 1949 Truax-Traer Coal Co. planned a cyclone installation at their Ceredo preparation plant to recover coal down to 150 mesh with approximately a 14-mesh top size. Since available centrifugal equipment was not considered satisfactory, an investigation of rotary vacuum filters was begun in cooperation with the Peterson Filters and Engineering Co. to determine the suitability of the Peterson Top Feed Reservoir (TFR) filter. This investigation, which is described below, has resulted in a highly satisfactory installation of two 6x10-in. Peterson TFR filters that have been in operation over a year. After some preliminary laboratory batch vacuum filter tests, a pilot plant double-drum Peterson TFR filter was installed at Ceredo to prove the feasibility of vacuum filtration and determine optimum conditions. The full scale units were then installed on the basis of the pilot plant results. This was followed by an extensive research program on vacuum filtration in the laboratory at Northwestern University to investigate basic design and operating variables and their influence on final moisture con- tent of the filter cake. A method of scale-up from laboratory batch tests to the full-size unit was also proposed and proved. Because of the importance of dewatering fine coal today, it was felt that the results of the three steps should be made available for the use of others facing this problem. The work at Northwestern is given in a theoretical section following the discussion of the pilot plant and full- scale operation. Fig. 1 is a flow diagram of the cyclone and filter installation. The feed is drawn from below the

Jan 1, 1952

By Sidney A. Swensrud

About a year ago, I attempted in a general way to trace the origin and development of some of the marketing problems of the petroleum industry, and to describe certain trends which it then seemed possible to foresee. To summarize briefly, it was pointed out that the consumption of gasoline, after increasing for more than a decade at an almost unbelievable rate, was slowing down, but that the two factors which determine the supply of gasoline —-namely, the production of crude oil and the percentage of gasoline derived therefrom—were tending steadily to mount. It was suggested that, while the increase in gasoline outlets began with and probably was justified at the start by the rapidly increasing demand, long after all reasonable requirements as to number of outlets had been met the number continued to increase—if anything, at a still more rapid rate—because by that time the overproduction of crude had begun to exert an impelling urge upon the owners of that crude to seek assured outlets for it in the form of gasoline. As more and more companies became integrated all the way from crude oil to marketing, there took place an ever-increasing competition among them, not only for the existing outlets but for new ones. The wide margin between wholesale cost and retail price, which is characteristic of the early stages of most new industries, persisted in the oil industry longer than in most industries, for various reasons. The existence of that wide margin provided in large measure the means of attracting new outlets, for as the gallonage per outlet declined with the increasing number of outlets, competing companies simply offered the dealers a larger part of the total margin. The very nature of competition suggests that such a process would continue until practically all of the available margin was thus given away, and such was clearly the tendency. It was a system that in turn produced increasing marketing expense per gallon on account of the diluted gallonage per outlet; this increased expense might seem to have provided a justification for continuing wide margins. Economics, like its parent, nature, however, progresses by mutations and so began to throw out new types of marketers, in the form of tank-car service stations, cut-price jobbers, and the like—heretics or

Jan 1, 1932

By Blamey Stevens

In this paper, which is a logical extension of my paper, The Laws of Intrusion,1 the various pressures of emanation and their mechanical causes and effects on the large scale of nature are determined, and a classification of emanations is deduced therefrom. • The Subterranean. Sea. The subterranean sea is here defined as the intercommnnicating water contained in the trains of pores and fissures of the rocks down to great depths. Whether the actual amount of water constituting this subterranean sea be large or small, does not enter into the present argument, since the static pressure of this water at any particular depth is not a function of the quantity : it involves only the depth and the density of the water. Densities. The total pressure at depths down to 10 or 15 miles is made up of the rock-stresses investigated in my previous papers, and the pressure of the subterranean sea. The latter component must evidently be equal to the weight of a solid column of the overlying water of unit sectional area. As mater expands with heat, it should really be necessary to sum the density at every level. A knowledge of the densities of mater under a variety of conditions is therefore needed, but does not seem ever to have been ascertained for such combined pressures and temperatures as we have to consider. The specific gravity of water at 28' C. for various pressures up to 400 atmospheres, has been determined by Barus, 2 who

Jan 1, 1913

By M. C. Udy, C. H. Lorig

THROUGH the years much interest has been centered in attempting to develop a direct method of iron-ore reduction, to replace or supplement the present indirect blast-furnace process. It would not be difficult to produce a list of more than 500 patents dealing with the direct production of iron and steel, but the few of this type of process that have proved successful do not produce in competition with the blast furnace; they produce special products. A survey of the literature reveals that the equilibrium conditions for the reduction reactions (iron oxides with carbon monoxide and with hydrogen) have been fairly well established but that data on the rate of reaction are discordant, although the general effects of the variables are known. This dissertation deals with the rate of reduction of a magnetite concentrate with hydrogen. The following variables have been studied: bed depth, gas velocity, particle size and temperature. The behavior of a single particle was also studied. LITERATURE Two general factors should be considered in a study of reduction of iron oxide: (I) equilibrium relations, and (2) rate of reaction. The first factor, equilibrium, has received the attention of many investigators and the equilibria Fe304-FeO-H2-H20, Fe3O4-FeO-CO-CO2, FeO-Fe-H2-H20, FeO¬Fe-CO-C02 are fairly well established. Of the second factor, the rate of reaction, much less is known. Data are comparatively scarce and there is very little concordance. The discordance probably results from the large number of variables influencing the reactions. However, the general effect of the variables is known. Among these variables are temperature, gas velocity, particle size, porosity, gas composition (distance from equilibrium), presence of impurities, greater or less prevalence of side reactions, and even design of the apparatus itself. Wetherill and Furnas1 published an excellent paper in 1934. They point out that any one or more of five processes (the chemical reaction, diffusion of the reactant through the gas film, diffusion of the reactant through the solid phase, diffusion of the reaction product through the solid phase, or diffusion of the reaction product through the gas film) may be the slow process, and thus the rate-controlling process. It is regretted that the work of these authors was limited to experiments at one temperature, and that the range of gas compositions was limited. Langmuir2 has shown that heterogeneous reactions take place at phase boundaries.

Jan 1, 1942

By D. E. Menzie, D. L. Dauben

This paper discusses the physical parameters involved in the slow flow of high molecular weight polymer solutions in porous media. The interacting effects of polymer properties and porous media properties on flow performance are considered. Experiments were conducted with the polyethylene oxides, with molecular weights ranging from 200,000 to over 5,000,000. Frontal advance velocities ranged from I to 30 ft/day. The porous matrix consisted of a flow cell packed with glass beads. Polymer solutions were characterized by viscosity and normal stress measurements. Under certain conditions, unexpectedly high flow resistance was observed. This behavior was observed to be a function of flow rate, pore size, polymer molecular weight and concentration. The polymer solutions exhibit "dilatant" flow behavior in porour media in contrast with the pseudo-plastic behavior in simple flow systems. A theoretical ex-planation of such behavior is presented. INTRODUCTION The use of polymers in the injected water of a waterflood increases oil displacement efficiency by reducing the mobility (k,/pu) of the driving phase. A reduced driving phase mobility results in improvements in the areal sweep efficiency and in the vertical coverage in stratified reservoirs. This mobility reduction may be achieved by a permeability reduction, a viscosity increase or by a combination of the two. Early attempts at increasing the injected water viscosity were not successful because of the poor economics involved. The use of such materials as glycerin, sugar or glycols to increase water viscosity was not economically feasible. Attempts in using certain naturally occurring polymers were not too successful because of the high polymer losses to the rock. A high molecular weight, partially hydrolyzed polyacry-lamide was introduced 3 years ago as a waterflood additive.',' Initial work by Pye' indicated that the presence of these polymers in dilute concentrations decreases the water mobility 5 to 20 times more than would be expected from measurements of the solution viscosity. Such an effect would be of obvious economic value since only a small polymer concentration would be required to accomplish a large reduction in water mobility. This research was designed to study the basic flow mech anisms of polymer solutions in porous media. The interacting effects of polymer properties and porous media properties on flow performance are considered. This study indicates some of the conditions under which these interactions can lead to significant mobility effects. is valid only for Newtonian fluids. For polymer solutions and other non-Newtonian fluids the equation must be modified to consider that viscosity is a variable quantity. Modification of the Darcy equation to include non-Newtonian effects has been the subject of several recent investigations."" The modifications generally adopt a rheological model. such as an Ellis or Dower law model. to Dorous media by defining some characteristic channel radius. Most of these studies showed the porous media flow behavior to be predictable from viscometric data. Investigations involving the flow of high molecular weight polyacrylamide solutions through cores have generally encountered the high flow resistances reported previously by Pye. This high flow resistance has generally been attributed to an in-depth permeability reduction, as evidenced by a reduced permeability to water which has displaced polymer solution from the porous media. Marshall and Metzner" report high flow resistances, which they attribute to viscoelastic effects. In this paper, the effects of polymer molecular weight, pore size, flow rate and concentration are considered. The polymers used are the polyethylene oxides known as Poly-ox. This class of polymers was used because of its availability in a wide range of molecular weights and because of its known ability to propagate well through porous media. THEORY PHYSICAL PROPERTIES OF POLYMER SOLUTIONS The polymer molecule dissolves in water by means of hydrogen bonding, but retains some of its own structural identity while in solution. Nonionic polymers, such as polyethylene oxide, are generally considered to have a random coiling configration. This type of molecule has the ability to "sequester" or hold a large volume of solvent within its coils in a manner similar to that of a sponge. The random coil is easily deformed and under an applied stress

By Z. T. Bieniawski

Tunneling in coal mines includes driving the main haulageways or roadways which serve as the development entries. Although constituting the lifelines of these mines, little attention has been paid to development entries in the United States in terms of systematic pre-construction planning and design. Coal mine tunnels, as the terminology is used in Europe and elsewhere, are understood in the United States to be the main development entries, either in room-and-pillar mining or in longwall mining. These development entries are not tunnels in the traditional sense since they usually are of a multi-entry type involving entries and cross-cuts, and their intersections. Thus, the design of coal mine tunnels is intertwined with the design of coal pillars. This paper summarizes the results of a three-year research project aimed at improving the design of development entries in U.S. coal mining. A design approach has been developed for this purpose and design procedures for roof support in main entries and for pillar sizing are proposed.

Jan 1, 1984

By E. R. Parker, C. F. Riisness

That grain size has a great effect on the mechanical properties of metals has been recognized for a long time. Bassett and Davis1 in 1919 did excellent work in determining the effect of grain size on the hardness of brass. About the same time Jeffries2 and Sykes3 ascertained the effect of grain size on the strength and ductility of several metals at temperatures ranging from 80°K. to their melting points. When creep was recognized as an important property of metals, those engaged in the study of this property tried to determine the effect of grain size4-9 on creep rates. Unfortunately, most of the investigations were conducted on only two grain sizes, often designated simply as "fine" and "coarse." It is well known that at high temperatures coarse-grained test bars creep less than fine-grained bars. The relation between grain size and size of test bar, however, has been frequently overlooked. In his early work, Jeffries2 showed that the number of grains in the cross section has a more important influence on the properties of the material than the actual grain size. More recently Hanson and Sandfordl0 and Pell-Walpole,ll in their measurements of the creep and tensile properties of tin, tested a wide range of grain sizes and correlated the grain size with the strength. Hanson9 later established the relation between the number of grains in the cross section and the creep rate. At high temperatures, generally a coarsegrained structure is considered superior in creep to a fine-grained structure, but it is evident that for a given bar size continuously increasing the grain size will

Jan 1, 1944

By C. F. Riisness, E. R. Parker

That grain size has a great effect on the mechanical properties of metals has been recognized for a long time. Bassett and Davis1 in 1919 did excellent work in determining the effect of grain size on the hardness of brass. About the same time Jeffries2 and Sykes3 ascertained the effect of grain size on the strength and ductility of several metals at temperatures ranging from 80°K. to their melting points. When creep was recognized as an important property of metals, those engaged in the study of this property tried to determine the effect of grain size4-9 on creep rates. Unfortunately, most of the investigations were conducted on only two grain sizes, often designated simply as "fine" and "coarse." It is well known that at high temperatures coarse-grained test bars creep less than fine-grained bars. The relation between grain size and size of test bar, however, has been frequently overlooked. In his early work, Jeffries2 showed that the number of grains in the cross section has a more important influence on the properties of the material than the actual grain size. More recently Hanson and Sandfordl0 and Pell-Walpole,ll in their measurements of the creep and tensile properties of tin, tested a wide range of grain sizes and correlated the grain size with the strength. Hanson9 later established the relation between the number of grains in the cross section and the creep rate. At high temperatures, generally a coarsegrained structure is considered superior in creep to a fine-grained structure, but it is evident that for a given bar size continuously increasing the grain size will

Jan 1, 1944

By C. E. Berner

Since 1933, the Coal Mine Rating Schedule in Pennsylvania has provided credits in the Workmen's Compensation insurance premium rates for the use of safety hats, goggles and shoes. In that year, the worth of such protective clothing had just been well established and satisfactory articles were being made by a number of manufacturers. Standards for these three items of safety clothing' were written in the Rating Schedule and have been little changed through the years. The credit in the premium rate for a bituminous mine is $0.14 for hats, $o.08 for goggles, $o.08 for shoes. In order to earn such credit, it is necessary that all the employees in the particular mine be equipped with safety hats, goggles or shoes, as the case may be. In fact, it is not unusual for mines to qualify in all three categories, thus earning a rate reduction of $o.30 per $100 of payroll. These credits have been a decided stimulus to the use of safety clothing, and at present insured bituminous mines are credited as follows: Hats........ 63 per cent, or 22,600 employees Goggles..... 28 per cent, or 10,000 employees Shoes....... 44 per cent, or 15,800 employees Of course, many other employees wear these protective articles but they are in mines that are not fully equipped and so are not given the rate credit. The growth in use of this equipment has not been spectacular but it has been steady, as shown in Table I. An interesting thing about this is that it covers virtually all of the small and medium-sized bitumi- nous mine operations in Pennsylvania. A number of large operations are included, but many large mines are self-insured. It is difficult to keep alive interest in safety work in the smaller mines: first, because employment of safety engineers is out of the question and the one or several mine officials employed are often concerned only with production; second, because the life of many small mines is brief, so that safe conditions although established do not last long. Conditions as to safety in mines of this class rest chiefly with inspectors of state mine departments and of casualty insurance companies. Many millions of tons of production come from these mines, so that

Jan 1, 1944

By C. E. Berner

Since 1933, the Coal Mine Rating Schedule in Pennsylvania has provided credits in the Workmen's Compensation insurance premium rates for the use of safety hats, goggles and shoes. In that year, the worth of such protective clothing had just been well established and satisfactory articles were being made by a number of manufacturers. Standards for these three items of safety clothing' were written in the Rating Schedule and have been little changed through the years. The credit in the premium rate for a bituminous mine is $0.14 for hats, $o.08 for goggles, $o.08 for shoes. In order to earn such credit, it is necessary that all the employees in the particular mine be equipped with safety hats, goggles or shoes, as the case may be. In fact, it is not unusual for mines to qualify in all three categories, thus earning a rate reduction of $o.30 per $100 of payroll. These credits have been a decided stimulus to the use of safety clothing, and at present insured bituminous mines are credited as follows: Hats........ 63 per cent, or 22,600 employees Goggles..... 28 per cent, or 10,000 employees Shoes....... 44 per cent, or 15,800 employees Of course, many other employees wear these protective articles but they are in mines that are not fully equipped and so are not given the rate credit. The growth in use of this equipment has not been spectacular but it has been steady, as shown in Table I. An interesting thing about this is that it covers virtually all of the small and medium-sized bitumi- nous mine operations in Pennsylvania. A number of large operations are included, but many large mines are self-insured. It is difficult to keep alive interest in safety work in the smaller mines: first, because employment of safety engineers is out of the question and the one or several mine officials employed are often concerned only with production; second, because the life of many small mines is brief, so that safe conditions although established do not last long. Conditions as to safety in mines of this class rest chiefly with inspectors of state mine departments and of casualty insurance companies. Many millions of tons of production come from these mines, so that

Jan 1, 1944

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 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 E. L. Anders

The Mile Six pool is located on the La Brea-Parinas Cullcession of International Petroleum Co., Ltd., in northwestern Peru on the west coast of South America. The reservoir pressure in this pool has been maintained within 200 psi of its initial value throughout its history, and gravity drainage has played an important role in the production behavior. It has now produced 95 per cent of its estimated ultimate recovery. It is estimated that this interesting oil pool will ultimately produce 67 per cent of the initial oil in place and that the resulting residual oil saturation may be as low as 19 per cent of the pore volume (29 per cent of the hydrocarbon pore volume). An evaluation of reservoir rock and fluid characteristics and ultimate oil recovery is presented. INTRODUCTION This study of Mile Six pool was made to evaluate its performance according to latest available information. The production performance of this pool has been discussed in various articles in the past. and the reported behavior has been used as an example for application of computation procedures for gravity drainage depletion' and as an illustration of field behavior under gravity drainage or expanding gas cap drive. There have been wide variations in reported values of initial oil in place, reservoir oil volume factor. connate-water sauration, volume of effective sand, and ultimate recovery because of the paucity of reliable basic data. These various factors have been determined as accurately as practicable with the latest available information, and this evaluation is presented herein. The production history of Mile Six is an excellent example of gravity drainage depleion with effective pressure maintenance by gar injection. GENERAL Mile Six pool was discovered by cable-tool drilling in November. 1927. when well 1996 was completed in the Parinas sand. After slow development with cable tools and sporadic production. the pool was opened to continuous pro(iuction in November. 1933. and develpment was completed with rotary rigs. Pressure maintenance was started in December, 1933. by returning gas to upstructure wells. Most of the development was 'completed by 1937, but some additional wells were drilled in the period 1939-1947. and several old wells were deepened. A total of 46 oil and gas wells and 4 dry holes were drilled on approximately 7-acre spacing. Of the producers. 21 are now flowing. 2 are pumping. 44 are gas input wells. 3 are abandoned. I is a gas well shut in. and 15 are shut in because of non-commercial production or high gas-oil ratio. The locations of all wells are shown on the map of Fig. I. Total oil production on Dec. 31. 1952, was 30,867,373 bbl: cumulative gas production was 22,023,777 Mcf; and 26,410,946 Mcf of gas had been returned to the reservoir. These figures do not include oil and gas lost ill a blowout in January. 1940. GEOLOGICAL DESCRIPTION Mile Six pool is located on the northern end of a structural spur projecting from the La Brea-Negritos uplift.' The spur is probably a reflection of a basement structure. It plunges gently to the north, i broken into a complex series of fault blocks. and contain.; the Verdun Alto. Section Sixteen. and Mile Six pools. The Parinas handstone (lower Eocene!. which is the producing formation in Mile Six. occurs at an average depth of 2,200 ft in the pool and dips north and east at from 15' to 20". The pool covers an area of approximately 350 acres. Mile Six is downfaulted about 600 ft from Section Sixteen pool to the soutb. and a major fault forms its western boundarv. The north and east boundaries are formed by the intersection of the sand top with the water-oil contact which occurs at approximately 2.440 ft subsea. An original gas-oil contact probably existed at about 1.875 ft subsea. Fig. 1 presents the latest structural interpretation of the pool. and Fig. 2 is an isopach map showing thickness of the total Parinas formation above the original water-oil contact. The heavy lints of Fig. 1 are contours on the sand top, and the fine lines are contours on the fault planes. This type of straight-line structural map was developed 1)) International's geologists to reflect structural conditions where the bedding planes dip and have no curvature. 'The La Brea-Parinas Concession is highly faulted by normal fault.. The beds are flat wherever exposed. The Parinas formation is approximately 635 ft thick. and it is etimated that 62 percent II the formation is effective sand. The original oil zone was about 565 ft thick. Fig. 211 presents an electric log showing typical Parinas sand development ill Mile Six pool. The Parinas band in Mile Six i. a well-sorted. medium- to-coal-se-grained. cross-bedded sand with minor lenses of shale and small lenses and pockets of pebble conglomerate. The sand grains are subangular to rounded and consist chiefly of quartz with feldspars. biotite hornblende, and augite as accessory minerals. Because of faulting of the Parinas- formation to the east and north of the pool. there is probably l possibility of a significant, natural water drive in Mile six. The faults within the pool. as indicated in Figs. 1 and 2. are of smaller disI,laceInent and seem to act only , partial barriers to fluid movement within the reservoir. RESERVOIR CHARACTERISTICS Core analysis data are available from five wells. The data were obtained from three wells (Nos. 3401. 3586 and 3719) at the time of their completion and from well 1996 when the original liner was sidetracked and the well was deepened ill 1946. Data from well 2779 were obtained in 1943 from old cores taken when the well was deepened in 1934. From these core analyses. the average porosity was estimated to be 22.6 per cent. and the average permeability to dry ail. was estimated to be 780 and Measured productility indices varied from 3.1 to 71.4 B/D per psi differential. Specific productivity indices varied approximately from 0.1 to 0.3 B./D per psi per ft of sand.

Jan 1, 1953

ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Member, graduate engineer, aged 44, with over 22 years' experience in connection with the development of large coal and coke properties in different parts of the country, desires position as general manager or general superintendent of large bituminous coal producer, or will take an interest and the management of a smaller operation. No. 258 Member, aged 41, mining engineer, manager or general superintendent, 20 years' experience, 10 years in Mexico, 5 years Western States, 5 years abroad. Guarantee results, fluent Spanish, excellent references. New York interview. No. 282. Member, technical mining graduate, 10 years' experience, especially in design, erection, construction and purchase of power and mining equipment and supplies, desires position in purchasing department. Married, aged 32, employed at present, references furnished. No. 295.

Jan 6, 1916