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By R. D. Sprague, C. B. Richardson

The year 1938 was the most active and successful in the history of the oil industry in southern Louisiana. Drilling showed a 16 per cent increase over that of 1937, with a total of 538 wells drilled, which yielded 315 oil wells, 19 distillate wells, 4 gas wells and 200 dry holes. Nineteen new fields were discovered during the year, all but three of which were completed by plugging back to sands previously drilled through. Electrical logging played a large part in these new discoveries as well as in the discovery of new sands during routine development of fields. Fourteen of the new discoveries produced oil, and five produced only gas and distillate. Southern Louisiana continues to lead the world in depth of drilling, which is in part due to the great thickness of comparatively young deltaic sediments near the coast and the existence of numerous sands. The present development is rather evenly distributed over a coastal strip 100 miles wide. New Fields North Tepetate, Acadia Parish.—Atlantic Refining Company's No. 1 Klumpp was completed for a new field through perforations from 7960 to 7970 ft. The initial production was 65 bbl. of 54" gravity distillate and 4 million cubic feet of gas daily through a 1/4-in. choke with tubing pressure of 2850 Ib. and casing pressure of 2930 lb. The well is in see. 12, 7 S., 2 W., just north of Tepetate field. It was drilled to a depth of 8705 ft. and plugged back for its final completion. Atlantic's NO. 2 was completed in a new sand at 8300 ft., also for distillate. South Crowley, Acadia Parish.—Humble Oil and Refining Company's No. 1 Boyd Finch was completed in July 1938, as an oil well through perforations from 7318 to 7325 ft. after plugging from a total depth of 10,222 ft. After making several hundred barrels of oil, the well went to

Jan 1, 1939

By C. B. Richardson, R. D. Sprague

The year 1938 was the most active and successful in the history of the oil industry in southern Louisiana. Drilling showed a 16 per cent increase over that of 1937, with a total of 538 wells drilled, which yielded 315 oil wells, 19 distillate wells, 4 gas wells and 200 dry holes. Nineteen new fields were discovered during the year, all but three of which were completed by plugging back to sands previously drilled through. Electrical logging played a large part in these new discoveries as well as in the discovery of new sands during routine development of fields. Fourteen of the new discoveries produced oil, and five produced only gas and distillate. Southern Louisiana continues to lead the world in depth of drilling, which is in part due to the great thickness of comparatively young deltaic sediments near the coast and the existence of numerous sands. The present development is rather evenly distributed over a coastal strip 100 miles wide. New Fields North Tepetate, Acadia Parish.—Atlantic Refining Company's No. 1 Klumpp was completed for a new field through perforations from 7960 to 7970 ft. The initial production was 65 bbl. of 54" gravity distillate and 4 million cubic feet of gas daily through a 1/4-in. choke with tubing pressure of 2850 Ib. and casing pressure of 2930 lb. The well is in see. 12, 7 S., 2 W., just north of Tepetate field. It was drilled to a depth of 8705 ft. and plugged back for its final completion. Atlantic's NO. 2 was completed in a new sand at 8300 ft., also for distillate. South Crowley, Acadia Parish.—Humble Oil and Refining Company's No. 1 Boyd Finch was completed in July 1938, as an oil well through perforations from 7318 to 7325 ft. after plugging from a total depth of 10,222 ft. After making several hundred barrels of oil, the well went to

Jan 1, 1939

By G. W. Form, W. A. Spitzig

The effects of hydrogen and vacuum shtering treatments on the physical and mechanical properties of arc plasma-sprayed tungsten were inuestigated. Temperatures examined ranged from 3000" to 4000°F in vacuum and 2000" to 3000°F in hydrogen for both single and duplex sintering cycles. Densities of 92 pct of theoretical density were obtained when a long-time hydrogen treatment at 2000°Fpreceded sintering in vacuum at 4000°F for 4 hr. This cycle also produced the highest ualues for modulus of rupture and bend angle. The results of this investigation point out the desirability of using a low-temperature long-time hydrogen treatment prior to a high-temperature vacuum sinter for arc plasma-sprayed tungsten. ADVANCES in the development of arc plasma-generating equipment have provided a high-temperature heat source that makes the fabrication of tungsten shapes possible by a metallizing process. Tungsten in the as-sprayed condition is very brittle. It has a density between 80 and 85 pct of theoretical density, a lamellar structure with elongated pores, and a high interstitial impurity content. To improve these properties, sintering treatments can be applied to the as-sprayed material, similar to those used for the densification of compacted tungsten powder. However, in view of the differences in the density and microstructure of as-sprayed tungsten as compared with compacted tungsten, responses to sintering were expected to be different. EXPERIMENTAL PROCEDURES The tungsten powder used in this investigation had a particle size varying from 3 to 13 p with an average diameter of 8p. The impurity level was less than 0.1 pct. The arc plasma spraying was done with an F-40 Thermal Dynamics Corp. plasma jet. Spraying was performed in air and thus required cooling of the substrate by an air blast in order to minimize oxidation. The spraying parameters employed in the fabrication of all specimens are listed below: Power input, kw 12 Arc-gas flow, cfh 95N2 + 5H2 Powder feed rate, g per min 33 Powder carrier gas flow, cfh ION, Spray distance, in. 3 Traverse rate, in. per min 30 Mandrel speed, rpm 100 Nozzle orifice, in. 7/32 These values of the spraying parameters correspond to optimum conditions ascertained in a previous study. Sintering was conducted at 3000°, 3500, and 4000°F in vacuum (< 0.1 Hg), and at 2000 and 3000°F in hydrogen. Duplex sintering treatments investigated are listed in Table I together with the designations that will be used for reference throughout this paper. The samples were fabricated by spraying onto a copper mandrel which was removed prior to sintering. The specimens used for the sintering analyses had the shape of small hollow truncated cones 1 in. high with an inside diameter varying from 0.500 to 0.125 in. and a wall thickness of 1/8 in. Specimens for bend testing were taken from hollow hexagonal prisms 1-1/2 in. high with a 1-in. diam across the flats and a wall thickness of 1/8 in. The bend-test specimens were ground to the dimensions 0.085 by 0.350 by 1-1/2 in. Prior to bend testing 0.0025 in. of stock was removed from each surface by electro-polishing. Density measurements were made by the water-displacement method. In addition, a porosimeter was used to determine the amount of interconnected porosity for representative samples. Strength and ductility were determined from recorded values in transverse bending using a cross head speed of 0.020 in. per min. The load was applied at the midpoint of a 1-in. span. The deflection data reported herein refer only to the plastic portion of the total deflection. RESULTS AND DISCUSSION The as-sprayed samples had a density corresponding to 83 pct (l pct) of the theoretical density of tungsten. Fig. 1 shows a representative as-sprayed tungsten structure.

Jan 1, 1964

By F. M. Lewis, J.F. Myers

The Tennessee Copper Company&apos;s operations are in the Ducktown Basin, in the extreme southeast corner of Tennessee. The ore is of the heavy sulphide type, the predominating sulphides being pyrite, pyr-rhotite, chalcopyrite and sphalerite. The gangue is a micaceous schist, with varying amounts of free quartz. The mining operation develops two classes of ore, each of which is concentrated by the flotation process in separate mills. Table 1 shows a typical analysis of the ore treated in each mill. The London mill was built in 1922, with a capacity of 400 tons per day. This was gradually increased to 600 tons by 1926, to 900 tons in 1928, and to 1350 tons in 1938. Fig. 1 shows the crushing and grinding flowsheet in 1928, when the capacity was 900 tons; Fig. 2, the crushing and grinding flowsheet that was developed by 1938, for the treatment of 1350 tons per day. A comparison of these flowsheets reveals that this increase in tonnage, with a subsequent improved operation, was accomplished with identically the same major equipment. Improving a concentrator&apos;s capacity, metallurgical results, and costs as time goes by is a commonplace practice, and is accomplished in various ways, depending upon the local conditions. The reason for presenting the data of how this was accomplished in the mills of the Tennessee Copper Co. is that a fast-running rod mill plays such an interesting role

Jan 1, 1943

By J. F. Myers, F. M. Lewis

The Tennessee Copper Company&apos;s operations are in the Ducktown Basin, in the extreme southeast corner of Tennessee. The ore is of the heavy sulphide type, the predominating sulphides being pyrite, pyr-rhotite, chalcopyrite and sphalerite. The gangue is a micaceous schist, with varying amounts of free quartz. The mining operation develops two classes of ore, each of which is concentrated by the flotation process in separate mills. Table 1 shows a typical analysis of the ore treated in each mill. The London mill was built in 1922, with a capacity of 400 tons per day. This was gradually increased to 600 tons by 1926, to 900 tons in 1928, and to 1350 tons in 1938. Fig. 1 shows the crushing and grinding flowsheet in 1928, when the capacity was 900 tons; Fig. 2, the crushing and grinding flowsheet that was developed by 1938, for the treatment of 1350 tons per day. A comparison of these flowsheets reveals that this increase in tonnage, with a subsequent improved operation, was accomplished with identically the same major equipment. Improving a concentrator&apos;s capacity, metallurgical results, and costs as time goes by is a commonplace practice, and is accomplished in various ways, depending upon the local conditions. The reason for presenting the data of how this was accomplished in the mills of the Tennessee Copper Co. is that a fast-running rod mill plays such an interesting role

Jan 1, 1943

Swedish mining companies are noted for their excellence in underground mining practice, and this classification certainly has to be applied to their design of crushing plants also. All these mines are highly mechanized with either rail or truck haulage, and typical examples of underground crushing plants designed for each of these haulage practices are presented here. Almost all the primary breakers are of the overhead eccentric, single- toggle jaw crusher type with units as large as 55 by 71 in. (1400 by 1800 mm) being used. In contrast to North America, where jaw crushers are almost always preceded by apron or vibrating feeders, many of the. Swedish crushers are choke fed with the dump pocket being located directly above the crusher. This practice results both from excellent knowledge of the ore characteristics and the ability of the overhead eccentric crusher to also act as a feeder. An excellent example of a crushing plant of this design is shown by the sketch of the LKAB Alliansen Crusher No. 64 at Malmberget, Sweden. Forty-six st (42 mt) trucks dump magnetite ore into a 91.6 cu yd (70 m3) dump pocket mounted over a 55 by 71 in (1400 by 1800 mm) Morgards- hammar overhead eccentric crusher using a 180 hp (132 kw) motor and belt drive. Crushed ore at 10 in. (250 mm) size drops onto an air- operated tipping chute which diverts the ore to either of two 1962 cu yd (1500 m3) pockets equipped with 3 ft 11 in. by 7 ft 11 in. (1200 by 2000 mm) Schenk vibrating feeders. Dust is drawn into a wet scrubber and exhaust air is combined with mine exhaust air. Because the crusher must be assembled underground, a 45/5 ton crane is installed over the crushing installation. A crusher above ground such as at Sacaton can easily utilize a smaller crane. Capacity of this &apos;most interesting crushing installation is 1653 st (1500 mtph) .

Jan 1, 1978

By Robert F. Brindisi

There are approximately thirty to forty operating mills in the United States which are currently producing uranium yellow cake. This figure includes a significant number of in situ and by-product operations however the conventional acid leach flowsheet depicted in Figure 1 is the most common process used by domes- tic yellow cake producers. Ground ore is leached with sulphuric acid and the solids are separated from the pregnant liquor and washed in a series of counter- current decantation thickeners. After clarification of the pregnant liquor, uranium is recovered from the solvent extraction/stripping circuit by the addition of ammonia with precipitation of ammonium diuranate, or simply yellow cake. The yellow cake precipitate is then thickened in a conventional thickener before re- porting to the dewatering/washing unit operation. De- watered solids subsequently report to thermal drying, and clarified liquor from the dewatering/washing step is recycled to the yellow cake thickener. The yellow cake dewatering/washing unit operation is generally accomplished using either a solid bowl centrifuge or a rotary vacuum drum filter. In most cases the underflow from the yellow cake thickener is pumped to the dewatering/washing unit operation at approximately fifteen to twenty percent solids. For the purpose of this discussion ammonium diuranate, the product of ammonia precipitation from a conventional acid-leach uranium mill flow sheet, as discussed earlier, will be considered. With only slight adjustment this discussion will be equally applicable to sodium diuranate or uranium perioxide precipitates and to either in situ or by-product operations where such precipitates are generated. Some of the domestic uranium mills which have selected solid bowl centrifuges instead of vacuum drum filters for the dewatering/washing unit operations are listed in Figure 2. Why have these uranium mills, as well as others not listed, chosen to use the solid bowl centrifuge for this particular application? It is simply a matter of performance, reliability and economics. In the remainder of this paper the performance, initial cost, installation cost, maintenance and power consumption of both the solid bowl centrifuge and the rotary vacuum drum filter will be com- pared. In order to provide a consistent basis for comparison the appropriate sized (centrifuge or filter) unit for the dewatering/washing of 400 to 500 pounds per hour of yellow cake solids will be considered. Such a flow will usually be generated by a typical 3,000 ton per day (acid-leach) uranium mill.

Jan 1, 1980

By R. P. Smith

IN 1937 the employees of the Hollinger Consolidated Gold Mines Ltd., at Timmins, Ont., Canada, approached organized medicine for a plan to provide themselves and their families with a complete medical service including hospitalization. This approach was made because of two conditions: (1) the necessity for some organization whereby contributions could be made in instalments to offset the sudden and large expense connected with illness for which the average employee is not prepared, and (2) the need for a more cohesive quality of service to replace a contract practice then in vogue, which did not take care of the employee&apos;s family or dependents. In different parts of the United States and Canada similar plans were in force, not only for employed groups but for numbers of people in circumscribed areas. In Europe different countries had adopted various forms of health insurance plans. It then was no surprise that these employees as a group should ask for some similar plan. With the cooperation of the management, a plan was instituted. The plan has one object only-the provision of medical services, including the accessory services such as hospitalization, X-rays, nursing, and necessary drugs and medicines. It is not concerned with cash benefits, sickness and accident payments, or any form of monetary return as the result of illness, but is simply an organization to provide medical services and pay for them from a central fund. It is a nonprofit organization and the only shareholders are the employees and their families who contribute and who in turn receive services. The Hollinger plan is limited to the employees of the Hollinger mine, who live in Timmins and the immediate vicinity. At first, the membership was voluntary. In the third year, it was made a condition of employment, with the proviso that at the end of any Association financial year an employee may withdraw if he wishes to do so. After withdrawal, he cannot again become a member until the end of the next Association year, and then only by the payment of the back dues. This step was taken to ensure continuity, and to prevent employees from withdrawing when well and reentering when faced with impending illness or operations. The employee himself is subject to medical examination on application for employment, and if accepted is subject to further examination by a specialist in chest diseases under the Workmen&apos;s Compensation Board of Ontario. Thus it is possible to exclude those who have heart disease, tuberculosis, or other disabling conditions when first employed. Wives and families of employees are not subject to medical examination but other dependents of an employee-mother, father, or other relative-who are declared by the employee to be wholly dependent upon him must be examined. The employee

Jan 1, 1944

By W. Luyken, E. Bierbrauer

A number of articles have been published, notably those by R. S. Handy, R. T. Hancock and A. P. Watt in Engineering and Mining Journal, dealing with the calculations involved in ore dressing. These publications demonstrate both the importance of the subject and the lack of success in developing a generally recognized method for comparing enrichment effects. Considering that we may wish to compare enrichment results on similar or dissimilar ores, that we may desire to make the comparison on the basis of either the absolute or the economical efficiency, and that the number of factors upon which the result depends is large, the question arises whether it is possible to set up a positive method for such calculations. In the following pages it is our aim to show that a sure, complete and successful way to overcome existing difficulties has been found. Graphical Analysis of Ore-dressing Processes The following is from Truscott&apos;s Text Book of Ore Dressing (London, 1923): x = assay of ore treated (feed). y = assay value of the concentrate. 2 = assay value of the tailing. a = weight of feed. 6 = weight of concentrate. c = weight of tailing. C = fractional concentration = = . a y - z K = ratio of concentration = 1/c a/b = y-z/x-z 2 B = fractional recovery = 9 = C y/x (3) 100R = percentage recovery. Copt. = theoretically best concentration. 100 — Copt = waste in the feed.

Jan 1, 1930

By George A. Laird

I. INTRODUCTION. THIS old and once famous district played, through its enormous production of silver and gold, an important part in the history of the State of San Luis Potosi. According to a pamphlet prepared under the direction of the Governor of the State, Sr. Don Blas Escontria, and presented to the visiting members of the Institute during the Mexican meeting of 1901, this district is situated 20 km. east of the city of San Luis Potosi, in a range of mountains of moderate height, extending 135 km. N. and S., and 16 km. E. and W.; and the mineralized area hitherto developed is about 600,000 sq. m. The history of the district,. as given by the record dated 1778, and formerly kept in the San Francisco convent, says that it was discovered in 1575 by Sr. Don Pedro Irarte, and adds that the city of San Luis Rey de Francisco del Potosi received its name (in allusion to the famous Potosi mines in Bolivia) by reason of the remarkable productiveness of its gold- and silver-mines in the first period of their exploration, during which they paid to the Crown, as " quintos " (the fifth part of the product), $97,000,000, as appears from the accounts of the royal treasury. The amount of the quientos paid during the " bonanza period " of 80 years was $72,000,000. The larger sum first mentioned probably represents a longer series of years. But either will suffice to indicate the great wealth of the mines. In 1663, the decadence of the industry began with the caving¬ in of several mines, concerning which the record of 1778, al¬ready cited, says, in substance, that on Good Friday one of the owners in the enterprise, in view of the unfavorable prospect of a lawsuit in which he was engaged, set fire to the timbers supporting the underground galleries and workings of the San

Jan 1, 1905

The following is an incomplete list of members and guests who called at Institute headquarters during the period Dec. 10, 1918 to Jan. 10, 1919. P. G. Bandy, Mexico City. Wm. B. McKinley, Yonkers, N. Y. Bennett R. Bates, Berkeley, Cal. Captain C. E. McQuigg, Conn. William T. Bates, Mascot, Tenn. Lt. H. G. Mathews, Cal. Lt. Don C. Billick, Alturas, Cal. Lt. M. S. Mazany, Mich. L. E. Booth, Watertown, Mass. Ralph A. Meyer, Hill City, S. D. J. T. Boyd, Denver, Colo. C. F. Moore, Boston, Mass. J. R. Buchanan, Pasadena, Cal. H. W. Nichols, Chicago, Ill. Ensign G. M. Burke. R. B. Olsen, Mays Landing, N. J. Captain E. H. Clausen. M. L. O&apos;Neale, Gouverneur, N. Y. F. L. Cole, Manila; P. I. F. W. Osborn, New York, N. Y. Joules Cousin. Lt. Fred S. Porter, Alaska. A. Faison Dixon, Washington, D. C. G. M. Richards, Palmerton, Pa. James T. Dixon, London, England. T. C. Roberts, E. Orange, N. J. Everett Drennen, Elkins, W. Va. W. E. Ruder, Schenectady, N. Y. F. Eichelberger, Helena, Mont. Ensign W. A. RuKeyser, Boston. R. B. Eldredge, Colorado Springs, Colo. A. H. Sawyer, Boston, Mass W. F. Ferrier, Ottawa. Lt. D. F. Schindler, New York. Martin Fishback, Benson, Ariz. L. G. Sparks, Greenshurg, Kan. T. E. Fisher, Dover, N. J. W. H. Staver, New York N. Y. D. C. Gilbert, Ft. Wayne, Ind. Douglas B. Sterrett, St. Cyr, Canada. Lt. Lauriston B. Herr, Cuba. Warren D. Thompson. G. S. Holmquist, Washington, D. C. Enrique Touceda, Albany, N. Y. Lt. E. Ross Housholder, Ohio. Mathew van Siclen. Hugh C. Ingle, Santa Rosa, Cal. Flying Cadet Christian Vrang, Cal. Lt. M. W. Kishman, Ariz. L. G. Weeks, Bisbee, Ariz. Hugo E. Koch, Watertown, Mass. C. E. Wheelock, Mogollon, N. M. H. M. LaFollette, LaFollette, Tenn. Major A. E. White, Washington, D. C. Clinton R. Lewis, Dawson, Y. T. Lt. J. L. White, Humboldt, Ariz. The Secretary of the Institute has received with sincere appreciation a Christmas card extending the season&apos;s greetings from the officers&apos; mess of the 3d Tunnelling Company, Canadian Engineers, B. E. F., France, and takes this means of reciprocating to these officers and men of the company the best wishes of the members of the Board of Directors. Charles E. Addams has removed from Ray, Ariz., to Phoenix, Ariz., where he is chairman and director of the Arizona State Council of Defense.

Jan 2, 1919

By H. D. Kessler, Joseph B. McAndrew

WHEN there is occasion to make structural use of metals at temperatures above 900°C (1652°F), the choice of alloys is severely limited, and those materials which meet special requirements as to density, strength, toughness, and resistance to creep, oxidation, or fatigue at such temperatures are at a premium. Any new type of high temperature alloy which is found to be outstanding with respect to several of these properties is therefore likely to find special applications for which it is uniquely advantageous as compared to other alloys. Such is the case with the 7 titanium-aluminum alloys. This y phase is an intermediate phase based on the composition TiAl, and extends from about 35.5 to 44.5 wt pct Al at temperatures up to 1000°C, above which the field broadens to include 60 pct A1 at 1340°C.&apos; The alloys of principal interest have a narrow melting range, with 7 forming by the peri-tectic reaction, melt + ß=y at about 1460°C. Unlike most intermediate phases, the binary alloys containing titanium and aluminum in approximately equiatomic proportion possess low room temperature hardness,&apos; in addition to which they have low density, good resistance to oxidation, and relatively high modulus of elasticity.&apos; Unpublished work done at Armour Research Foundation showed

Jan 1, 1957

By Gerhard Derge

A SERIES of studies of the corrosion of tin is under way in the Metals Research Laboratory at the Carnegie Institute of Technology. The complete program includes examination of the corrosion properties of high-purity tin and the changes produced in these properties by the addition of varying amounts of alloying elements. Other studies of this subject have been made recently under the sponsorship of the International Tin Research and Development Council, but these researches have been confined largely to the weakly acid environments commonly encountered in the canning industry.1 There is little information available regarding the corrosion of tin under alkaline conditions, but such data would be of value, for a large amount of the metal is used under such conditions. The potential measurements to be described were made because they seemed to offer the most rapid method for obtaining a general view of the conditions to be encountered in such service. These experiments will also serve to establish a technique that will be of value in further studies. It must be emphasized that the results reported are those of controlled laboratory experiments and that the conclusions drawn cannot yet be applied to service conditions; rather, they point to the directions in which more exhaustive experimental work may be done to best advantage. EXPERIMENTAL PROCEDURE The first work was devoted entirely to the problem of obtaining reproducible results from a series of potential measurements. Only the methods finally adopted as standard will be described here, except when the variations from these have furnished results of interest. The cell used is shown schematically in Fig. 1. The electrolyte is contained in the vessel A (an inverted bell jar), whose ground top is fitted to the transite-board lid B. The controlled atmosphere can be admitted

Jan 1, 1938

By Max W. Ball

An intelligent discussion of the oil situation and its needs, whether from the standpoint of the prospector, the operator, the engineer, or the public administrative officer, must be founded upon a knowledge of the law under which oil lands are obtained. A consideration of new legislation must be prefaced by an understanding of the present law and its results. This paper undertakes to present no new remedy for the ills of the present situation, no new solution of the problems the oil business is facing. It attempts merely to summarize the present law, its provisions, its origin, its development, and its effects. The discussion does not pretend to be exhaustive from a legal standpoint. It aims to avoid legal intricacies which tend to. confuse rather than clarify. It seeks but to present the essentials of the existing situation. The title to government lands known to contain valuable deposits of petroleum may be acquired only under the terms of the placer law as embodied in Section 2329 et seq. of the Revised Statutes. As a preliminary to considering the desirability of this situation it is profitable to examine into its origin. Origin of the Law Congress has left no room for doubt as to the legal applicability of the placer law to oil lands. The Act of Feb.11, 1897(29 Stat., 526), provides: "that any person authorized to enter lands under the mining laws of the United States may enter and obtain patent to land containing petroleum or other mineral oils, and chiefly valuable therefor, under the provisions of the laws relating to placer mineral claims.&apos; . The immediate cause for the passage of this Act was stated in a brief report in the, House of Representatives (there was no debate in the Senate) to be a decision of the Department rendered Aug. 27, 1896 (Union Oil Co., 23 L. D., 223), directing the cancellation of an oil placer entry on the ground that land containing petroleum cannot be located and entered as a placer mine. The report of the Public Lands Committee of the House contains the following interesting statements Congressional Record, vol. xxix, p. 1409):

Jan 1, 1915

By G. G. Priest, B. E. Morgan

The production of oil and gas from wells is often seriously hindered by the compaction of solids in the perforations during the perforating process. To realize the full productive capacity of a well, it is necessary either to remove the plugging material from the perforations or to perforate in a manner which does not cause plugging of the perforations. The latter method can be accomplished by having a non-plugging fluid in the casing at the time the well is perforated. This paper describes the results of laboratory tests, perforating tests, and experimental field tests which demonstrate that certain emulsions serve effectively as non-plugging perforating fluids. The principal components of these emulsions are two liquids: an aqueous phase consisting of a solution of either sodium chloride or calcium chloride, and an oil phase consisting of diesel oil, tetrachloroethylene, or a combination of both. Small amounts of other agents which serve to stubilize the emulsions, to reduce the fluid loss, and to inhibit corrosion are also present. The density of the emulsions is controllable within the range of 7.5 to 12.5 lb/gal; no insoluble solids are present, the filtration rate is low, and the thermal stability is satisfactory at temperatures as high as 200°F. The corrosion of steel by these emulsions is negligible. Tests conducted under conditions which simulate the temperature and the pressure in an actual well demonstrate that these emulsions fulfill the requirements of a non-plugging perforating fluid. In addition, lirnited field experience furnishes evidence that these emulsions remain in position after they are spotted, that they are retained in the casing after the perforations are made, and that they are easily removed from the perforations when the well is opened for production. When the pressure in the borehole is greater than the formation pressure at the time a well is perforated, plugging of the perforations can be avoided by spotting an emulsion adjacent the interval to be perforated. This procedure should eliminate low well productivity caused by plugging the perforations. INTRODUCTION Nature of Problem The most widely used method for the completion of oil and gas wells is to set and cement casing through productive horizons, and then to obtain production by gun-perforating the section of casing opposite the desired interval. This method is gen- erally successful and it was thought at one time that those failures which did occur were due to insufficient penetration by the perforator. Despite recent improvements in perforators which assure ample penetration, unsatisfactory fluid production continues to be a problem. Evidently, the trouble comes from some other source. Recent results obtained by Allen and Worzel1 demonstrated that low fluid productivity may be caused by the perforating process and/or by the fluid in the wellbore at the time of shooting. They found that perforations are often completely plugged by debris from the perforator, pulverized sand from the formation, and compacted solids from the drilling mud when the pressure in the wellbore is greater than the pressure in the formation at the time of perforation. In some cases a differential pressure in excess of 400 psi was required to initiate flow into the well through these plugged perforations. The plugging of perforations by solids not only causes low productivity from wells, but it creates simultaneously other problems in the production of oil and gas. For example, when most of the perforations are plugged, high rates of flow must occur through the few perforations that are open. The resulting high pressure drop may cause production

Jan 1, 1958

By David Yob

INTRODUCTION This paper is intended to fulfill three major purposes. The first of these purposes is to narrate the improvements to the ventilation of Northeast Churchrock Mine and the subsequent reduction of the radiation levels. The second major objective is to pass on to persons unfamiliar with the ventilation of radon and radon daughter producing mines some of the most important characteristics of airborne radiation and the control thereof. The third objective is to describe the use of a computerized digital mine ventilation simulation. This description is not only of the usage, but also some of the important methods and techniques involved in the usage. This paper is not intended for the persons with extensive experience in these areas. However, to those persons who are just becoming involved with either ventilation of mines with airborne radiation problems or persons interested in computer simulation, this paper should be of some interest. It is the author&apos;s experience that most of the information on either computer simulation or airborne radiation control either assumes an extensive knowledge on the part of the reader, or does not address the direct application of the information contained in these articles. It is for that reason that this paper intends to concentrate on the actual application of the topics covered. INITIAL STATUS In the first quarter of 1980, the author and others became involved with the ventilation effort of the Northeast Churchrock Mine. At this time, this team began an investigation of the mine ventilation with the intent of reperforming a mine pressure survey. During the course of this investigation, it was determined that the ventilation system was inadequate. During this first quarter, the responsibility for ventilation of the mine was transferred to the author and his team. It was determined that the system that was in use was that of the single entry or haulage return type. In this type of system, there is very little direct control of the airflow, and it is not an effective type of ventilation for mines that experience problems due to airborne radiation. In a single entry, or haulage return, system there is no separate return system provided. In the system, as we found it, the only source of intake air to the ore level working areas was from the track level. This intake air was forced into the ore level, or stope level, via bulkhead fans installed on raises from the track. This air, after being used in the working areas, was then allowed to find its own way back to the exhausting vent holes. There was essentially no control of this air from the bulkhead fan discharge to the vent hole. The only control used was by the sizing of the fans on the raises. The main portion of this air used the haulage and access drifting for return. Due to the large horsepower used in these bulkhead fans and the large resistance both between the areas to the vent holes and inadequate intake ducting, the stope level pressure was higher than the track level. This pressure differential caused a severe recirculation between the stope level to the track level. This recirculation also caused a severe pre-contamination problem to the supposedly fresh intake air, making his air nearly unusable for working area ventilation. [ ] It was found at the time our ventilation effort began, that the radiation levels were high enough to make compliance with the four working-level month per year standard impossible. For this reason, we had to spend several months driving costly development drifts to implement a completely different type of ventilation system. Before describing the system that was implemented to solve the problems that were discovered during our initial investigation, some discussion of the characteristics of airborne radiation due to radon and radon daughters is needed. RADON CHARACTERISTICS AND RELATED TECHNIQUES One of the most notable characteristics of radiation contamination caused by radon and radon daughter decay is that once the contamination has entered the airstream, the radiation levels as measured in working levels will continue to rise without any further contamination. This radiation rise will eventually stop

Jan 1, 1982

By C. P. Sandberg

C. P. Sandberg, London, Eng. 1 think we should all be grateful to the Pennsylvania Railroad Company, and to their chemist, Dr. Dudley, for spending so much time and money in order to solve an important question; nor are me less indebted to the public spirit which leads them to impart tlie experience thus gained. In Europe nothing similar has hitherto been done, either by a company or by any private individual. In England the great railway companies employ their engineers in other ways, and do not keep a chemist or specialist to study rails; bat even if they did they would probably not publish the results. The chief professional engineers are so occupied with their private practice of railroad construction generally, that they cannot be expected to devote their time and energies to so special a question. The German Railway Union has, in my opinion, missed the real object of its elaborate researches by falling into the error of specifying costly, impracticable tests for rails—tests at the same time which do not infallibly expose the impurities that may be in the rails under examination. There has, therefore, been nothing done on this side of the Atlantic in the way of exhaustive study to determine the best composition for steel rails. America should consequently have full credit for the enlightened example which she has set. I wish, however, to make a few remarks on Dr. Dudley&apos;s second paper,—& paper which follows very much upan the same lines of argument as the first red three years ago, upon which I have previously touched in my pabr on the same subject read at the meeting in August last. If Dr. Dudley had discovered a new metal he could hardly, I think, have taken wore pains to prove that he was correct in his first formula for the best chemical colnposition of steel rails. But I hare seen so much done in the way of proof by experiment that I am inclined to think that almost anything can be proved by experiments and by satnples. If Dr. Dudley would only give up his formula, which would not suit any country—not even America—

Jan 1, 1881

By C. O. Lee, Z. W. Bartlett, R. H. Feierabend

The Grand Isle sulfur mine is located in the Gulf of Mexico, approximately seven miles off the coast of Grand Isle, Jefferson Parish, La. The deposit is on acreage covered by oil, gas, and mineral leases originally issued in favor of Humble Oil & Refining Co. by the State of Louisiana which were continued, maintained, and redesignated by the U.S. Department of the Interior after passage of the Outer Continental Shelf Lands Act. The sulfur deposit was discovered in 1949 when Humble Oil & Refining Co. penetrated more than 200 ft of sulfur-bearing limestone in a zone between 1813 and 2075 ft below sea level. In 1954, Humble drilled ten more sulfur prospect holes, eight of which encountered sulfur ore. On September 19, 1956, Freeport Sulphur Co. acquired from Humble Oil & Refining Co, the sulfur rights underlying the tracts, and the actual design of the installation began the same month. The first structural contract was awarded in December 1957 and offshore erection began in June 1958. The initial phase of construction has been completed and production by the Frasch process commenced in April 1960. The estimated total cost of the project is $30 million, of which $8 million is the extra cost incurred by the necessity of offshore operations. More than $22 million was expended before production was started. GEOLOGY OF DEPOSIT Grand Isle is the third largest sulfur deposit in the U.S. The orebody embraces several hundred acres, but its outer limits are yet to be defined to the northeast, east, and south. Most Gulf Coast sulfur deposits occur in a caprock mantle of calcite (referred to as limestone), anhydrite, and occasionally gypsum, which covers the apex of an intrusive mass of salt. Commercial quantities of sulfur are usually confined to the calcite or limestone member. Most often such limestone is completely enclosed by dense anhydrite below and impervious sediments above, which effectively form a closed reservoir. The depth of the Grand Isle orebody ranges from 1800 ft to 2500 ft below sea level. Within the present boundary, the sulfur-bearing limestone varies in thickness from 220 ft to 425 ft, while the sulfur content varies an average of about 15 pct in the leanest hole to an average of about 30 pct in the richest. Rock containing less than 5 pct sulfur is not classed as ore, and holes assaying less than 20,-000 long tons per acre of sulfur in place are not considered commercial offshore. The sulfur enrich-

Jan 1, 1961

C. P. Sandberg, London, Eng. 1 think we should all be grateful to the Pennsylvania Railroad Company, and to their chemist, Dr. Dudley, for spending so much time and money in order to solve an important question; nor are me less indebted to the public spirit which leads them to impart tlie experience thus gained. In Europe nothing similar has hitherto been done, either by a company or by any private individual. In England the great railway companies employ their engineers in other ways, and do not keep a chemist or specialist to study rails; bat even if they did they would probably not publish the results. The chief professional engineers are so occupied with their private practice of railroad construction generally, that they cannot be expected to devote their time and energies to so special a question. The German Railway Union has, in my opinion, missed the real object of its elaborate researches by falling into the error of specifying costly, impracticable tests for rails—tests at the same time which do not infallibly expose the impurities that may be in the rails under examination. There has, therefore, been nothing done on this side of the Atlantic in the way of exhaustive study to determine the best composition for steel rails. America should consequently have full credit for the enlightened example which she has set. I wish, however, to make a few remarks on Dr. Dudley&apos;s second paper,—& paper which follows very much upan the same lines of argument as the first red three years ago, upon which I have previously touched in my pabr on the same subject read at the meeting in August last. If Dr. Dudley had discovered a new metal he could hardly, I think, have taken wore pains to prove that he was correct in his first formula for the best chemical colnposition of steel rails. But I hare seen so much done in the way of proof by experiment that I am inclined to think that almost anything can be proved by experiments and by satnples. If Dr. Dudley would only give up his formula, which would not suit any country—not even America—

Jan 1, 1881

By F. McIntosh Galbraith

THIS paper describes the use of the magnetometer, under geological direction, in exploration of the Sudbury nickel district. The writer&apos;s experience at Falconbridge has led him to the belief that only through detailed work, and by careful correlation of both geological and geophysical results, can geophysical prospecting methods be applied successfully to mining exploration problems. It is hoped that the basic technique described in the paper will be found to have general application.

Jan 1, 1942