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By W. D. Smith

It has been 5 years since the writer left the Philippine Islands and while in that country his chief work did not lie in this field, though he has visited all but one of the localities mentioned in this article. The principal field studies relating to oil were M de by his colleague, Mr. Wallace E. Pratt. The writer's investigations ealt with the general stratigraphy and paleontology of the Philippines. with the exception of the investigations made by Mr. Pratt and the writer very little information on this subject is available. A number of geologists in the employ of large oil companies have visited the Islands from time to time but, following the general rule, the public has scarcely ever been permitted to learn anything of the results. The writer is indebted to the Bureau of Insular Affairs, Washington, for late information regarding recent legislation in the Islands relating to petroleum. All the known oil seeps, petroleum residues, such as ozocerite, and natural-gas emanations are associated with Tertiary sediments. The chief seeps and most promising prospects are located as follows: 1. Bondoc Peninsula (lower end), Tayabas Province, Southeast Luzon. 2. The west coast of the island of Cebü from Alegria north to, and perhaps beyond, Toledo. 3. Central Mindanao not far from Lake Lanao. 4. The ozocerite veins on the Island of Leyte in the northwestern part in the vicinity of the town of Villaba. 5. Natural gas from some deep wells in Tertiary shale formations on the eastern flank of the Cordillera and extending out under the plain on the island of Panay. The first mention in geological literature, to the writer's knowledge, of gas or petroleum in the Philippines is found in the description of the Island of Panay by the Spanish geologist, Abella, in the year 1890. In 1898, an oil well was being dug on the estate of Smith Bell & Co., an English concern, near the town of Toledo on the west coast of Cebu. In

Jan 1, 1921

By Olin M. Hart

Uranium ores occur in the Lower Cretaceous Inyan Kara group of heterogeneously stratified fluvial and fluvial-marine sandstones in the Black Hills of western South Dakota and northeastern Wyoming. There are three principal mining districts, each in the ancestral and present drainage area of a major river partially responsible for stripping the region to its present topographic form. Primary minerals in the deposits are coffinite and uraninite with minor amounts of paramontroseite and haggite. The ore minerals coat sand grains and fill interstices of complexly cross-stratified sandstone along solution fronts similar to "roll" type deposits of the other districts. Minerals of oxidized deposits are typically carnotite and tyuyamunite with different proportions of secondary vanadium accessory minerals. Ground water was the transporting medium and deposition of primary uranium and vanadium minerals occurred in reducing environments produced and controlled by physio-chemical characteristics of the sedimentary rocks.

Jan 1, 1968

By Paul A. Beck, M. N. Parthasarathi

The vecrystallization texture. formed by selective growth of random nuclei in an 80 pct volled 99.997 pct A1 crystal of initial orientation mear (123) (41.21 was found to consist of components related to the single-component rolling texture by 40 deg. rota-tiows around [111]axes. The relative-volume fractiovz of the various recrystallization-texture componezts may be accouzted for 012 the basis of the Lou) mobility of twist boundaries, if it is assumed that the mobility of the tilt boundaries also varies with their orientation. Similar results with a, aluminum-alloy cystal of the (110) [112] orientation, containing iron, silicon, and zinc, show that these solute contents do not impair the effectivezess of the oriented growth mechanism of re cry s-tallization- texture formation. In a previous investigation1,2 it was found that a sharp recrystallization texture is formed as a result of the oriented growth of random artificial nuclei in an aluminum crystal rolled to 80 pct RA, on the (110) plane in the [ 112] direction. Four recrystallization-texture components were found to occur, with orientations corresponding to 40-deg rotations around [111 1 axes of the deformation texture. Reorientations of this type were already found in earlier work,3,4 where the presence of random nuclei could be reasonably assumed, but was not rigorously documented. The same orientation relationship was found also by Lucke and Liebmann, who actually measured the orientation dependence of boundary-migration rates in the recrystallization of A1 crystals slightly deformed in tension.5,6 The occurrence in the recrystallization texture of only four of the eight crystallographically equivalent orientations of the type referred to above remained unexplained,1,2 although it was clearly not a result of the absence of suitable nuclei. Recently Burgers7 suggested that this effect may be due to the aniso-tropy of boundary mobility observed2'6; it was found that the recrystallized grains of the 40-deg [111]-rotated type grow much faster in directions perpendicular to the [ 111] they have in common with the matrix than parallel to this direction, i.e., the tilt boundaries have much higher mobility than the twist boundaries. The four orientations corresponding to

Jan 1, 1962

By C. J. Osborn

In oral discussion at the Columbus midyear meeting, September 26, 1949, these pertinent questions were asked: Was a satisfactory separation of metal and matte obtained? The matte was quite fluid and in most cases the separation was satisfactory. Were the mattes chlorinated after aging? The mattes were stored in sealed glass mason jars, and chlorina-tion experiments made after standing for several weeks gave satisfactory results. Was ferric chloride volatilized? Most of the iron content of the matte was converted to ferric chloride. However, because of the low chlorination temperatures used (150" to 250°C) the major part of the ferric chloride remained with the residue. Undoubtedly, some ferrous chloride was also formed, because of the reducing conditions within the reaction vessel, but no effort was made to separate it from the ferric chloride. Could the reaction be stopped before making metallic iron? No attempt was ever made to stop the reaction before making metallic iron. Generally, 20 to 60 pct of the iron in the charge was obtained as metallic iron which could be readily separated from the matte. In certain cases, metallic iron was dispersed through the matte in the form of globules, which could be removed by magnetic separation. Could other sulphides, i.e., calcium sulphide or sodium sulphide be used in place of iron sulphide? No other sulphides were investigated. It was felt that titanates of calcium and sodium would be formed should these sulphides be used to replace the pyrite. What were the sulphur volatilization losses during matte smelting? In the course of this laboratory investigation, a rather wide variety of variables was introduced from highly oxidizing to reducing conditions and various ratios of pyrite, rutile, and coke. These and other factors all have a definite bearing on the sulphur losses. In general, the higher the sulphur in the charge the higher were the sulphur losses and the percentage of titanium in the matte decreased. With sulphur additions more nearly the theoretical amount, the sulphur losses averaged approximately 10 to 15 pct. With a higher percentage of sulphur on the charges, the losses were in the order of 15 to 30 pct.

Jan 1, 1951

By C. M. Young

THE safety lamp is the most common and convenient apparatus for detecting inflammable gases in mines, the presence of gas being shown by a blue flame, called the cap, if the wick has been lowered to suppress the luminous flame. The height of the cap increases with the proportion of gas and with the temperature of the lamp flame. Lamps of the Wolf type, the fuel of which is benzine, have a hotter flame than lamps in which vegetable oils are used, such as the Davy, and the Clanny, and are more sensitive than the latter and their many modifications. The Piehler alcohol lamp gives a still higher cap while the Clowes hydrogen lamp is most sensitive of all. While the effect of the temperature of the source of ignition is well known, the writer knows of no previous attempt to correlate the change of this temperature with change of the height of the cap produced. In order to determine the height of the cap at various temperatures, it was necessary to have a source of ignition the temperature of which could he accurately controlled over a considerable range. This condition was met by a coil of wire of high fusing point heated by an electric current controlled by a variable resistance. The use of a coil offered the further advantage of freedom from complications due to the flame of a burning fuel. Such a flame, being itself of variable height, would to some extent raise or lower the elevation of the base of the cap and therefore add to the difficulty of determining the height of the cap. Besides this, the presence of a small cap from the lamp fuel, commonly known as the "fuel cap, " would interfere with the observation of small gas caps. After some experiment, a coil was made of platinum wire, No. 26, diameter 0.016 in. The coil was 17/64 in. (6.746 mm.) in outside diameter and had eight full turns in a length of ½ in. (12.69 mm.). This was connected to an electric circuit through an adjustable resistance, as shown in

Jan 8, 1919

. F. W. SPERR, JR.,* Pittsburgh, Pa.--Mr. Malcolmson states that the Carbocoal process produces ammonium sulfate in excess of that normally recovered in the ordinary byproduct coke process. Table 3 indicates that 20,000 to 25,000 lb. of sulfate of ammonia are obtained in carbonizing 1000 tons of Clinchfield coal. This is a high-grade coal and yields from 26 to 28 lb. of ammonium sulfate per ton in a modern byproduct coke oven. On the next page, 21 lb. is stated as the yield of ammonium sulfate per short ton of raw coal; this is less than the average production from any well operated byproduct coke-oven plant treating coal of the character usually coked, in Pennsylvania and Ohio. The statement as to the comparative yields of light oil is somewhat misleading in view of the results obtained during the past year or two by the more modern byproduct coke plants. The plants put in operation by the H. Koppers Co., during the past two years, are producing about 3.5 gal. of light oil per short ton of coal, and several of these plants are producing more than 4 gal. per ton. The yield of pure toluene runs from 0.45 gal. to 0.55 gal. per ton. .The quality of the light oil .obtained from the Carbocoal process is of much greater importance than would be inferred by one not closely familiar with the subject. The presence of paraffins in the benzol and toluol fractions seriously detracts from their commercial value; the benzol and toluol fractions derived fro in the Carbocoal process contain about 50 per cent, of paraffins. It should be thoroughly understood what these paraffins are. They are simply hydrocarbons that go to make up ordinary petroleum, and if a successful method for the removal of paraffins from benzol and toluol has been developed, this can at once be applied to several well known processes by which benzol and toluol can be made directly from petroleum, which have as yet been total failures on account of the contamination of these products by paraffins.

Jan 11, 1918

By K. R. Price, M. Gauna

A high seam geologic condition exists at Jim Walter Resources No. 4 mine that requires immediate rib support after a continuous miner cuts a place. High seam mining heights are typically 2.4 to 2.6 m (8 to 9 ft) and a thick rock layer is present in the upper portion of the coal rib side. The 610-m (2000 ft) mining depth at No. 4 mine induces horizontal rib line movement after excavating an entry. Horizontal rib movement greater than 305 mm (12 in.) have been noted. When lateral movement occurs in the high seam areas, the thick rock layer, and the coal above the rock layer, become fractured and tend to roll into the entry. If not adequately supported, large rib rolls develop in the place being bolted as well as in previously mined areas that endanger men and equipment. To control this, rib support must be installed in the roof bolting operation as the bolting crew works toward the face. A rib control system has been developed for this high seam mining condition using a mechanical anchor bolt placed at an angle in the rib and installed with a modified Fletcher DDM-15 bolting machine. More than 120 km (75 miles) of entry have been supported with angle rib bolts. These angle bolts constitute 43% to 60% of the total roof and rib bolt footage in the high seam portions of No. 4 mine. The angle rib bolting system has proven safer, more effective, and more efficient than the earlier support method using bolts installed horizontally into the rib. No rib roll accidents have occurred since the angle drill bolting machines were placed in service in 1981. By securing the broken rib material with an angle bolt anchored above the coal pillar, a more effective means of rib control is achieved. Angle rib bolting does not interfere with continuous miner productivity. In addition, bolting crews are now reduced from three to two people. Total drilling supply costs are about 60% the previous cost, when compared to the previous support method using horizontal rib bolts:

Jan 1, 1985

By Wilson B. Emery

The Hidden Dome gas field, situated in Washakie County, Wyoming, was discovered Sept. 26, 1917. Subsequently five additional gas wells were completed and a large reserve was developed. For a number of years this field completely supplied the domestic market at Basin and Greybull, as well as the refinery at the latter town, and it is still supplying gas in small amounts to this market. Production is obtained from the sands of the Frontier formation at depths ranging from 1000 to 1500 ft. The original rock pressure was 725 Ib. and initial production ranged from 4,000,000 to 28,000,000 cu. ft. per day per well. Porosity of the sand, determined from the size of the productive area and the amount of gas recovered, is over 18 per cent. Area and Management It is estimated that the productive area is about 640 acres. Its outline is indicated on Fig. 5, on which are also shown the locations of holes drilled on the structure and the area of unit operation. The unit area is owned by the Ohio Oil Co. and development and operation have been by this company. No productive well has been completed outside this area. The entire area was Government land filed on under the placer mining law. Results of Unit Operation With six producing wells, or an average of one to each 160 acres, the pool is completely developed. Location of the wells was made with respect to structural conditions plus the requirement that at least one well be drilled on each 160-acre placer claim. Perhaps a somewhat more uniform spacing of the wells might have been accomplished and one well eliminated, but it must be borne in mind that the holes, on account of their shallow depth, were not expensive and that the object was to develop as reliable a reserve as possible. There is no cause to suspect that these holes have not adequately drained the reservoir and there is every reason to think that any additional wells, which might have been drilled under diversified ownership and operation, would have been an economic waste. Unit operation by a competent company has not only resulted in the elimination of loss of gas through careless development and operation

Jan 1, 1930

By C. A. Stetefeldt

FoR the convenience of those who do not care to enter into the details of this long essay, I begin with a summary of the most important results it presents. The extraction of silver by the lixiviation-process from ores which have been subjected to a chloridizing-roasting, is based upon the fact that silver chloride is easily soluble in solutions of sodium or calcium hyposulphite, and that silver is precipitated from such solutions by an alkaline sulphide, with regeneration of the hyposulphite salts. In case the ore contains lead a large portion of the latter is and dissolved, lead sulphate being soluble in hyposulphite solutions. If, at the same time, copper is present, the sulphides precipitated from the solution, contain silver, copper, and lead, a combination of metals not desirable for subsequent treatment. Mr. E. H. Russell, of Park City, Utah, is the inventor and the patentee in the United States and several foreign countries of a new lixiviation-process, based upon the chemical facts discussed in this paper. Mr. Russell has discovered that lead can be completely separated from a sodium hyposulphite solution, as lead carbonate, by sodium carbonate or purified soda-ash, without precipitating any copper or silver. After decanting the solution from the lead carbonate, silver and copper are obtained from it in the usual way. This method of separating lead prohibits the use of calcium poly-sulphide as a precipitant for the sulphides, because any calcium entering the regenerated lixiviationsolution would also be precipitated as a carbonate with the lead by soda-ash. Hence, a sodium sulphide must be employed. A full investigation has demonstrated that this is by no means detrimental. Sodium sulphide and hyposulphite are more advantageously used in the lixiviation-process than the corresponding calcium-salts. Another defect in the lixiviation-process consisted in the necessity of a very perfect chlorination of the silver in the ore, because silver in

Jan 1, 1885

By H. J. Struth

The benefits of proration of oil production were perhaps more concretely realized in 1932 than at any time since the oil industry adopted nation-wide production control. Reduced output of crude petroleum, which brought the daily average of the United States down to approximately 2,000,000 bbl. from a peak in 1931 of more than 2,600,000, had a telling effect on the trend of oil prices. Mid-Continent crude was advanced in price from 776, for 36-gravity oil, to $1.04 a barrel. California crude, of 26-gravity at Signal Hill, moved forward from 736 to 976 a barrel. Pennsylvania crude, the only exception to the upward trend, rose in price from $1.82 per barrel to $2.02, only to react to $1.72. This was due to local conditions which necessitated an adjustment to overcome competition from other areas of the United States. East Texas continued to exert a far-reaching influence on the crude and gasoline market during 1932. Despite the fact that oil prices were advanced in most fields, large quantities of oil were produced in East Texas in violation of state proration orders, and sold in the market at prices considerably below official postings. This created competitive conditions in the gasoline market that were felt by all refining centers of the United States. The quantity of gasoline produced from cheap East Texas crude was not large, but the volume was sufficient to influence prices in practically all sections of the country. Thus, while the industry's' economic situation showed visible improvement statistically, the unreported and unseen statistics originating in East Texas proved to be an insurmountable obstacle to the economic betterment that was otherwise apparently justified. Somewhat surprising to many was the fact that gasoline consumption was maintained within 10 per cent of the preceding year. Domestic consumption showed only a net decline under 1931 of about 8.5 per cent; exports dropped in volume to the extent of about 23 per cent. As a matter of fact, domestic gasoline consumption was only about 1.4 per cent less than it was in the predepression year of 1929. Exports, however,

Jan 1, 1933

By Victor L. Stevens

The Oso tunnel is one of three tunnels located on the San Juan-Chama Project in south-central Colorado. The purpose of the tunnel is to carry water from the upper San Juan watershed through the Continental Divide into the Rio Grande watershed. The Oso tunnel contract was awarded by the U.S. Bureau of Reclamation to a joint venture of Boyles Brothers Drilling Co., Gibbons & Reed Co., and Cimco in February 1966. The Oso tunnel is 26,660 ft long and has a rock section of 10 ft, 2 in. with a lined diameter of 8 ft circular. The main portion of the rock formation was in the Lewis shale. This formation is quite consistent in hardness and texture with exception of localized limestone concretions and sandy siltstone inclusions. The job was bid on the basis of using a James S. Robbins mole of the P221 series. The decision for using a mole was predicated on the geology and the experience of the same joint venture on the adjoining Azotea tunnel where a mole was successfully used. The Robbins P221 series mole is capable of cutting from 9 ft, 11 in. to a 10 ft, 7 in. diam without any major change. It is 40 ft long and weighs 60 tons. The cutting head has 22 disk-type cutters and one center pilot (standard 9 7/8 -in.) tricone bit. The head is powered by four 75 hp electric motors. Gripper pads at about the midway point on each side of the machine are pushed into the tunnel ribs and thrust-cylinders in front of each gripper apply pressure to the face as the head rotates. The regripping cycle is 3 ft and then the grippers are retracted and advanced. Each cutter on the perimeter of the head is followed by a bucket which scoops up the cut material, almost in the same manner as a water wheel, and dumps it into a conveyor situated along the top of the mole. The muck from the mole conveyor is dumped into a gantry-type conveyor. The gantry conveyor is 350 ft long and is pulled

Jan 1, 1970

By W. V. Bluck, W. L. McMorris

Higher coal quality is being recognized in potentially lowering the cost of power as measured at the bus bar. Assessment of potential coal supplies for most power plants is now going beyond buying at the lowest delivered fuel cost. It is now taking into consideration other factors, such as handling, storage, pulverization cost, boiler fouling, post combustion cleanup, and waste disposal costs. New measurements of quality are being considered now by those producing and those consuming the fuel by assessing numerous variables in the total fuel cycle to achieve the lowest possible power costs.

Jan 1, 1986

By J. L. W. Birkinbine

INTRODUCTION. This paper is a discussion of a part of the mineral wealth of the States of Oaxaca and Puebla, Mexico. It does not refer to the precious metals, some miles of which, in these States, are said to have been worked before the advent of the Spanish conquistadores in the sixteenth century, as my purpose is to invite attention to the exploration of deposits of coal and iron-ores in the Mixteca region. The prominence given to coal is warranted by the great effect of the scarcity of fuel upon the industrial development of Mexico. Under the progressive administration of President Porfirio Diaz, the Republic has made wonderful advances in the past three decades; and this progress would have been greater but for the limitations imposed by expensive fuel. In the spring of 1906 I was detailed by the Birkinbine Engineering Offices, of Philadelphia, to accompany A. B. Adams, of New York, in a reconnoissance of reported deposits of iron-ores in the State of Oaxaca. The result of this expedition was the formation, in 1907, of the Oaxaca Iron & Coal Co., of which Mr. Adams became, and has remained, President and General Manager, and I have spent the past three years as Chief Engineer of this company in Mexico, principally in western Oaxaca, where field-headquarters were established. GEOGRAPHY AND POPULATION. Although the geographical anti topographical, features of the Republic of Mexico are well known, few realize that the majority. of its population is domiciled in the States which immediately surround the capital city of Mexico, including the Federal District, Mexico, Tlaxcala, Morelos, Puebla,

Sep 1, 1910

By J. E. Howard

On Aug. 25, 1911, a rail failed on the Lehigh Valley Railroad, causing a disastrous wreck. The surface of the fracture was in a plane at right angles to the length of the rail. There was a dark-colored, oval spot on this surface, located on the gage side of the head, representing the part of the rail which was the first to fracture. The nucleus of this spot showed that the fracture had an interior origin. Other fractures of this kind, the peripheries of which had not reached the surface of the rail, presented surfaces having a (silvery luster. The darkened surface of the present fracture was caused, doubtless, by the air having had access to it. This fracture was recognized as a fatigue fracture, of a modified type, its interior origin having been due to a component in the rail which is not usually present in cases of fatigue fractures. The metal next the running surface of the head of the rail was in a state of internal compression, this being the component not commonly met with in other cases, and which caused the fracture to have its interior origin. For the purpose of giving this modified type of fatigue fracture a specific name, for identification, the term "transverse fissure" was applied. No mystery was thought to attach to its formation, or to its development. The explanation of its occurrence seemed obvious in the light of common knowledge upon the behavior of steel under repeated alternate stresses.' By reason of the state of internal compression at the running surface, the maximum tensile stresses in the head, ander bending loads, were along an interior element. Here the tensile strains were higher than in the fibers more remote from the neutral axis. Under such conditions the fracture of the rail would be expected to have an interior origin. A discussion of the subject of transverse fissures essentially becomes a discussion of fatigue fractures, since they are believed to be identical. The descriptive term employed, merely for the identification of this type of fatigue fracture, had the appearance of creating alarm. Apprehensions arose that a new phenomenon in the physical properties of steel had presented itself, the explanation of which was sought in every

Jan 1, 1918

By E. A. Holbrook

IN view of what has happened in - the past three years, it seems incredible that industrial corporations continue to write to engineering and mines schools for "promising members of the graduating class," or, indeed, that they even send representatives to the colleges to interview engineering graduates. Certainly, by this time, every company should be aware of the fact that recent engineering graduates are almost nonexistent and the number is not likely to increase within the next several years. At the February, 1945, annual meeting of the Local Section delegates of the A.I.M.E. in New York, W. B. Plank, professor of mining engineering at Lafayette College, summarized well the situation of the colleges by titling his talk "The Lost Generation of Engineers."

Jan 1, 1945

By Alfred H. Bell, George V. Cohee

Illinois produced 146,788,000 bbl. of oil in 1940, or nearly 11.0 per cent of the total for the United States, and ranked fourth among the oil-producing states. Its production was only slightly less than that of Oklahoma, which produced 11.5 per cent of the national total. Illinois' production in 1940 represents an increase of 55 per cent over the previous year, when it amounted to 94,912,000 barrels. The development of the Devonian limestone in the Salem and Centralia fields is largely responsible for the increase in production during 1940 Production from the Devonian limestone in these two fields was estimated to be 36,698,000 bbl., or 25 per cent of the state's total production (Table I). The increase in production during June, when the state's daily average production attained a peak of 518,200 bbl. for the week ending June 29, was due to the Devonian production at Centralia (Fig. I). The initial production of the best Devonian wells in the Centralia field was as high as 12,000 bbl. in 24 hr. Daily average production in IIIinois for 1940 was 400,000 bbl. of oil, but actually daily production fluctuated widely during the year. At the beginning of 1940 daily production was approximately 330,000 bbl. During the first hali of the year it in-creased irregularly to the peak in June mentioned above and as the prolific Devonian producing areas were drilled up, the state's daily production declined rapidly during July and continued to decline, although more slowly, until the end of the year, when the daily production was approximately 325,000 bbl. The daily average production per well in the new fields at the end of the year was approximately 40 bbl. (Fig. I). Oil from the Devonian was also produced in the Bartelso field, Clinton County, the Sandoval field, Marion County, and the Irvington field, Washington County, bringing the estimated total production from the Devonian limestone to about 26 per cent of the state's total production, The remainder was obtained largely from the Mississippian system. About 2 per cent of the total was from Pennsylvanian and Ordovician strata. The decline in the Devonian limestone production has been so rapid that the 1941 output from this system will probably be only a small fraction of that of 1940 unless large new reserves are discovered. The "Trenton" (Ordovician) limestone has been tested in two wells in the Centralia field and both were small oil producers at a depth of about 4000 it. The "Trenton" also was found productive in the Salem field at a depth of 4500 ft. (Table 5). The initial production of the discovery well, which was completed shortly after the end of the year, was 130 bbl. on pump. Other wells drilled early in 1941 had initial productions averaging 172 barrels. The outlook for 1941 is for a continuation of drilling activity in Illinois, but at a declining rate (Fig. I, upper curve). The most active area at the end of 1940 was in the deep basin area in Wabash, Edwards, White, and Hamilton Counties.

Jan 1, 1941

By Alfred H. Bell, George V. Cohee

Illinois produced 146,788,000 bbl. of oil in 1940, or nearly 11.0 per cent of the total for the United States, and ranked fourth among the oil-producing states. Its production was only slightly less than that of Oklahoma, which produced 11.5 per cent of the national total. Illinois' production in 1940 represents an increase of 55 per cent over the previous year, when it amounted to 94,912,000 barrels. The development of the Devonian limestone in the Salem and Centralia fields is largely responsible for the increase in production during 1940 Production from the Devonian limestone in these two fields was estimated to be 36,698,000 bbl., or 25 per cent of the state's total production (Table I). The increase in production during June, when the state's daily average production attained a peak of 518,200 bbl. for the week ending June 29, was due to the Devonian production at Centralia (Fig. I). The initial production of the best Devonian wells in the Centralia field was as high as 12,000 bbl. in 24 hr. Daily average production in IIIinois for 1940 was 400,000 bbl. of oil, but actually daily production fluctuated widely during the year. At the beginning of 1940 daily production was approximately 330,000 bbl. During the first hali of the year it in-creased irregularly to the peak in June mentioned above and as the prolific Devonian producing areas were drilled up, the state's daily production declined rapidly during July and continued to decline, although more slowly, until the end of the year, when the daily production was approximately 325,000 bbl. The daily average production per well in the new fields at the end of the year was approximately 40 bbl. (Fig. I). Oil from the Devonian was also produced in the Bartelso field, Clinton County, the Sandoval field, Marion County, and the Irvington field, Washington County, bringing the estimated total production from the Devonian limestone to about 26 per cent of the state's total production, The remainder was obtained largely from the Mississippian system. About 2 per cent of the total was from Pennsylvanian and Ordovician strata. The decline in the Devonian limestone production has been so rapid that the 1941 output from this system will probably be only a small fraction of that of 1940 unless large new reserves are discovered. The "Trenton" (Ordovician) limestone has been tested in two wells in the Centralia field and both were small oil producers at a depth of about 4000 it. The "Trenton" also was found productive in the Salem field at a depth of 4500 ft. (Table 5). The initial production of the discovery well, which was completed shortly after the end of the year, was 130 bbl. on pump. Other wells drilled early in 1941 had initial productions averaging 172 barrels. The outlook for 1941 is for a continuation of drilling activity in Illinois, but at a declining rate (Fig. I, upper curve). The most active area at the end of 1940 was in the deep basin area in Wabash, Edwards, White, and Hamilton Counties.

Jan 1, 1941

By Richard J. Robbins

Mechanical moles have developed through a tedious process of evolution. At times it has seemed that tunnel borers have been subject to the same Darwinian rules of evolution as their zoological namesakes who, despite their efficiency, are highly specialized and still restricted to soft soil conditions near the surface of the ground. HISTORICAL HIGHLIGHTS The Robbins Co. began its work in this field in 1947 with the development of a twin-bore continuous coal miner. Although these machines were used primarily in coal, two of the early prototypes were used to bore tunnels through shale. Disk cutters were first used on these machines and showed promising results as core breakers between drag-bit kerfs. In 1953, James S. Robbins and Assocs. undertook the development of a 25-ft 9-in.-diam circular tunnel borer for Mittry Construction Co. to be used at Oahe Dam in South Dakota (Fig. 1). This is believed to be the first rock tunnel-boring machine built since the end of the 19th century when short sections of the Channel tunnel were successfully bored in chalk from both the English and French shores. Another Oahe Dam machine was built in 1955, and then a series of three small-diameter machines for the company's first real experience with medium-hard and hard rock (Fig. 2) None of these three could be considered a success, although they laid the groundwork for the success that followed. Interbedded shale and limestone in Pittsburgh and hard limestone in Chicago quickly pointed up the weaknesses in these machines which were used by Perini, Dravo, and Healey. Among the problems were the high breakage rate of tungsten-carbide drag bits, too much flexibility in the drive shafts, failure of high-pressure hydraulic systems, chain-conveyor failure, and general lack of rigidity and strength. In 1956 another attempt at medium-hard and hard rock-boring proved this time to be a success and a significant turning point in the development

Jan 1, 1970

Jan 1, 1905

By D. R. Cook, W. M. Shepard, H. T. Morris

The East Tintic district in central Utah has produced ores of gold, silver, copper, lead, and zinc valued at more than $120,000,000. All of this ore has been produced from blind ore bodies in Paleozoic sedimentary rocks that are concealed beneath hydrothermally altered volcanic rocks and cut by intrusive bodies of Eocene age. The Paleozoic rocks, which range in age from Early Cambrian to Mississippian form the core and limbs of a large, northtrending asymmetric anticline that is cut by low-angle thrust faults, high-angle transcurrent faults, mineralized fissures and faults, and normal faults that are both older and younger than the mineralized fissures. The ore bodies generally may be grouped into two classes: ( 1) massive replacement bodies that are rich in silver, lead, zinc and manganese and (2) fissure veins that are valuable primarily for their content of gold, copper, and silver. The replacement ore bodies are localized chiefly in the Middle Limestone Member of the Ophir Formation of Middle Cambrian age where it has been thrust-faulted against older or younger rocks and cut by northeast-trending mineralized fissure zones. The fissure veins primarily are productive only in the Lower Cambrian Tintic Quartzite. Extensive lowgrade deposits of lead-zinc-silver ore recently have been discovered in Devonian carbonate rocks in the Lower plate of the East Tintic thrust fault but as yet are unevaluated. The principal guides to ore include: ( 1) intersections of northeast-trending fissures and crossbreaking faults that brecciate the carbonate rocks; (2) zones of late-stage pyritic, calcitic, and sericitic alteration in the lavas; ( 3) primary geochemical anomalies in the altered rocks; and ( 4) mineral zoning patterns of the known ore bodies. The present development of the Burgin mine would seem to assure the continued productivity of the district for at least a decade.

Jan 1, 1968