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By D. H. Yardley

ENGINEERS and geologists find the magnetic compass unreliable in many mineral bearing areas because of local magnetic attraction. This is the case in the vicinity of many contact deposits, and particularly true in the Lake Superior district where iron formation is wide spread and causes wide fluctuations of the magnetic needle. One of the most useful instruments for geologic traversing or running grid and claim lines under these conditions is the dial compass which does not depend upon magnetism. Difficulties encountered in the field because of local attraction can be overcome through transit observation of Polaris or the sun, or use of the solar attachment. However, a field party often lacks the equipment or time for work of such accuracy and it is here that the dial compass finds its use.

Jan 3, 1954

By Kevin B. Doyle

The export markets are of great importance to western Canadian sulfur producers, taking 70% of total products sold. For these marketers, Canadians have always supplied solid sulfur, first in a crushed, bulk form, and for the past several years in a slate form. Both form have proved inadequate for safety and environmental reasons, and new forms and processes have been developed by interested suppliers. The Canadian industry has evaluated these processes and ha made a determination of a desired Product specfication that will greatly enhance the acceptability of future Products from safety, environmental, and customer points of view. The new processed methods and resulting product characteristics are reviewed.

Jan 1, 1980

By Walter White

THE measurement of the reading of a thermoelement is the measurement of an electromotive force extraordinarily small compared to those generally used in commercial work. Of the various possible methods of measuring such a quantity, the most advantageous is always a delicate galvanometer. Since a galvanometer measures current, it is necessary to adopt some scheme by which its current reading shall indicate electromotive force. There are two general methods of doing this. One is to use the delicate galvanometer as a "direct reader," that is, to let the electromotive force of the thermoelement furnish the power and produce the current measured. If the resistance is constant the reading will, after a suitable calibration, give the electromotive force of the thermoelement which, by means of a table or of a suitable scale in the galvanometer itself, will FIG. 1.-SIMPLIFIED POTENTIOMETER. POTENTIAL DROP ACROSS THE PART PIN or CIRCUIT OF BULL CELL BALANCES THAT OF THERMOELEMENT TC WHEN GALVANOMETER G READS ZERO. give the temperature. The other method, that of the potentiometer, is to balance the electromotive force of the thermoelement by means of another electromotive force, using the galvanometer to tell when the balance is made. The usual way of getting this other electromotive force is to have a battery, the "bull" cell, send a current through a series of resistances, which 'may in a special case be the resistance of a single wire. The fall of potential along this circuit will then, by Ohm's Law, be proportional to the resistance; the potential difference between any two points, proportional to the resistance between the two points. This is represented in Fig. 1, where M and N are the two points in the circuit AZ of the battery. If M or N, or both, is movable so that the resistance

Jan 9, 1919

By R. Lagneborg

WhEN mechanical twins initiate cracking it has been proposed1 that the friction stress for dislocation motion, in the Cottrell criterion for brittle fracture2 should be replaced by the stress required to propagate a twin, ttp. TF is the fracture stress, d the grain diameter, ß a geometric constant, u shear modulus, and y the effective surface energy. Since TTp is likely to vary with grain size, it cannot be substituted by a constant in Eq. [I]. If an expression for the energy change caused by a twin in a stressed material could be obtained, it is in principle possible to compute the critical size of the twin, i.e., the size at which the system can decrease its energy spontaneously, as a function of applied stress, thus giving the stress required to just barely propagate the twin, i.e., TTP. Consider a circular twin disc with a radius r and having a lenticular cross section, Fig. 1. Twin dislocations3 of strength b exist in the twin boundary parallel to the twin plane, one loop on each atomic plane. Assume that the total numbers of loops, n, can be replaced by one circular loop of a multiple dislocation, nb with a radius r. The energy change of the system, AW, due to such a twin in an applied stress field can then be calculated: The first term is the total twin surface energy, the second the elastic energy due to the twin dislocations, and the third the energy released by the twin in the applied stress field. yt is the twin boundary energy, r, the radius of the dislocation core, and T the applied

Jan 1, 1968

By W. H. Geis

The following pages summarize the causes that led to the suggestion of unit operation of the paloma field, the organization of com-mittees, preparation of the Paloma Operators Agreement and the reasons for rejection of the plan. Introduction Long ago an Austrian physicist observed that under certain conditions the condensation of a liquid from gaseous mixtures resulted from pressure reduction. Some 50 years later he would have known that his research was not in vain. He would have seen a group of serious operators and engineers seeking to apply that principle to a conservation . program for unitized production in the Paloma gas field—but he would also have been saddened to see that forces unsympathetic to the application of science in oil production, with little or no appreciation of modern methods and the advantages of cooperation, so far have prevented the adoption of that program. Soon after the Paloma field was discovered it was realized that all the hydrocarbons in the reservoir existed in the gaseous phase. This condition was confirmed over a large area. Therefore, if the field was to be properly exploited with the greatest ultimate recovery of condensate, the hydrocarbons in the reservoir must be produced in the single or gas phase. They must be cautiously extracted with the least possible reduction of the natural pressure. If this could be accomplished, or if artificial pressure control were utilized, the condensation and underground loss of the valuable distillate would be preventable—otherwise it would not be. Wholehearted cooperation of all oper-ators was required in order to accomplish the conservation purposes of the program. To this end the production engineers of the several companies concerned lent their time and talents. They fully investigated the physical relationships of the products within the complicated gaseous mixture, prepared extensive reports on the subject and drew up a reasonably efficient plan of operations, which now is commonly called the "Paloma Unit Plan" but actually was entitled "The Paloma Operators Agreement." All of the engineers were not in perfect agreement on all the features of the plan, or even on all the engineering principles. However, it is safe to say that on all the important or essential factors there was a unanimity of opinion, particularly as to the objectives. These were fairly simple and reduce to one controlling item, "pressure control" by cycling or recycling. Organization The principal operators initiated the program by calling a meeting of all the lessees in the area, at which an organization was perfected, known as the "Paloma Operators Committee." Various subcommittees were appointed to expedite the work, including an "Engineering Committee." These func-tioned in a businesslike manner, frequently reported to the superior committee and

Jan 1, 1942

By W. H. Geis

The following pages summarize the causes that led to the suggestion of unit operation of the paloma field, the organization of com-mittees, preparation of the Paloma Operators Agreement and the reasons for rejection of the plan. Introduction Long ago an Austrian physicist observed that under certain conditions the condensation of a liquid from gaseous mixtures resulted from pressure reduction. Some 50 years later he would have known that his research was not in vain. He would have seen a group of serious operators and engineers seeking to apply that principle to a conservation . program for unitized production in the Paloma gas field—but he would also have been saddened to see that forces unsympathetic to the application of science in oil production, with little or no appreciation of modern methods and the advantages of cooperation, so far have prevented the adoption of that program. Soon after the Paloma field was discovered it was realized that all the hydrocarbons in the reservoir existed in the gaseous phase. This condition was confirmed over a large area. Therefore, if the field was to be properly exploited with the greatest ultimate recovery of condensate, the hydrocarbons in the reservoir must be produced in the single or gas phase. They must be cautiously extracted with the least possible reduction of the natural pressure. If this could be accomplished, or if artificial pressure control were utilized, the condensation and underground loss of the valuable distillate would be preventable—otherwise it would not be. Wholehearted cooperation of all oper-ators was required in order to accomplish the conservation purposes of the program. To this end the production engineers of the several companies concerned lent their time and talents. They fully investigated the physical relationships of the products within the complicated gaseous mixture, prepared extensive reports on the subject and drew up a reasonably efficient plan of operations, which now is commonly called the "Paloma Unit Plan" but actually was entitled "The Paloma Operators Agreement." All of the engineers were not in perfect agreement on all the features of the plan, or even on all the engineering principles. However, it is safe to say that on all the important or essential factors there was a unanimity of opinion, particularly as to the objectives. These were fairly simple and reduce to one controlling item, "pressure control" by cycling or recycling. Organization The principal operators initiated the program by calling a meeting of all the lessees in the area, at which an organization was perfected, known as the "Paloma Operators Committee." Various subcommittees were appointed to expedite the work, including an "Engineering Committee." These func-tioned in a businesslike manner, frequently reported to the superior committee and

Jan 1, 1942

By Frank Wilder

THE most important process in a gypsum mill is calcining the crude mineral. There seems, however, to be little progress or change in calcining methods. This would not be surprising if the industry was not, in other ways, developing. The demand for gypsum in its various forms, however, is growing rapidly. The output has more than doubled in six years, while the value of gypsum products, through the introduction of higher priced specialties like wall board, has nearly trebled in the same period. In other industries, under somewhat similar conditions, calcining in rotating cylinders, either by direct or indirect heat, has replaced the method that still prevails in gypsum mills. Efforts were made to use rotary calciners in manufacturing plaster of Paris in the early days of the industry in America; 25 years ago rotary calciners were in use in Germany. At that time there was great diversity of opinion in regard to their merit. In 1923, the output of calcined gypsum in the United States was 3,101,378 tons. About nine-tenths of this material was calcined in kettles, the remainder in rotary calciners. The ratio was about the same 10 years ago. During these 10 years, rotary calcining made rela-tively no gains, and there were no important changes in the construction of kettles. In their manipulation, the only change of consequence was in connection with the length of time that the gypsum is left in the kettle. For wall-plaster purposes, all producers who had not previously done so changed from second-settled to first-settled calcined gypsum, thereby reducing production costs and improving the plasticity and sand-carrying capacity of their plaster. Nevertheless, in the few mills in which they were installed, rotary calciners continue to operate, with possibly one or two exceptions, and to be highly successful. In these 10 years, the Cummer type of rotary calciner has disappeared. All rotaries now used are of the cement-mill type with a diameter of 6 or 7 ft. and length of 80 to 120 feet.

Jan 2, 1925

By James Douglas

At this last meeting of our Institute for the year 1899, it is appropriate that we should look back at the past. To review the century's progress in the exact sciences and the resulting arts that fall within the scope of our labors is beyond my ability. But I wish to draw your attention to some phases of that progress, almost as important, which lie within the zone of sociology, touching at so many points the domain of applied technology. One of these is suggested by the library of technical literature which this century has produced —not the least important contribution to which is our own Transactions. The nineteenth century has witnessed the beneficial spread of democracy in politics. Under the impulse, to no small degree, of the same spirit, there has grown up a brotherhood of fellow-workers and a sense of fellow-ownership in the secrets of nature. Though the Patent Office has assumed such proportions as to hare become a source of national revenue, and a multitude of inventors, great and small, are seeking through its agency to secure some pecuniary profit from their devices, there is even greater eagerness among both interested and disinterested workers in the field of technology to publish their observations, and even their discoveries, and to give them to the world without remuneration. The motives influencing the great body of writers who, without any pay, use the technical journals and such media of communication as our Transactions, in order to give to the brethren of their craft the results of

Jan 1, 1900

Chester Wells Purington was killed at Yokohama on Sept. 1, 1923, in the Japanese earthquake. Mr. Purington was born in Boston, Mass., Oct. 27, 1871. He prepared for his entrance to Harvard at the Boston Latin School and graduated from Harvard in the class of '93. He started out soon thereafter investigating gold deposits of the Appalachian system in the South and in 1895, made atrip to Alaska, investigating the gold deposits of that territory. The summer and fall of 1896 found him in the San Juan country of Colorado examining the gold and silver properties in the Telluride and Rico districts and in the La Plata Mountains. In the meantime, he had served on the economic staff of the U. S

Jan 1, 1924

By George F. Comstock

IT has been reported recently1 that the hardenability and toughness of forging steels may be improved appreciably by the use of complex deoxidizers containing titanium, aluminum, and vanadium. In the light of these results, an investigation of similar deoxidizers containing various hardening and grain-refining elements was proposed. These deoxidizers included three manganese-silicon-aluminum-titanium al- [ ] loys with and without boron and calcium, three titanium-aluminum ferroalloys with vanadium, molybdenum and zirconium, respectively, an aluminum-zirconium ferro-alloy, and plain ferroboron. Their approximate compositions are given in Table I, and the results obtained so far in the investigation of their effects on steel are presented in the later parts of this paper. METHOD OF USING DEOXIDIZERS The deoxidizers listed in Table I were used in three series of 0.40 per cent carbon steels, which were melted in a small basic-lined induction furnace and cast in the form of I7-lb. ingots about 2.75 in. square. The basic charge for each heat was 10 lb. Armco iron and 6 lb. of clean low-carbon sheet-steel scrap. When melted, this charge was deoxidized with 15 grams of ferrosilicon, then about 500 grams of pig iron was added to give the desired carbon content. After the pig iron was dissolved, nickel [ ] shot and high-carbon ferrochromium were added if required, and additions of 80 per cent high-carbon ferromanganese and 50 per cent ferrosilicon were made to provide the proper amounts of those elements. Aluminum was added to every heat 2 min. after the silicon, for grain-size control and preliminary deoxidation. One minute later the special deoxidizer was added to the clean bare surface of the molten steel, and 2 min. afterward the steel was poured into the ingot mold, using a hot-top and pipe-preventing compound after pouring to decrease the depth of the shrinkage cavity. The special deoxidizers were used mostly in the form of about ½ to ¾ -in. lumps,

Jan 1, 1942

By B. N. Whittaker, C. J. Bonsall

The paper gives an account of the factors influencing the stability of coal mining tunnels and goes on to examine various bases of support and lining design of such tunnels in relation to geological and mining conditions. The different types of coal mining tunnels are compared and comments made regarding the factors influencing their choice and basic design features. Foremost amongst design considerations is the design method and special thought has been given to the validity of different formulae as related particularly to UK Carboniferous geological conditions. Emphasis is placed on the role of the stress field in relation to tunnel stability. Shape of mining tunnel has been investigated and conclusions drawn regarding the merits of different commonly excavated geometries from a stability point of view. Detailed design aspects pertaining to determination of tunnel lining strength and resulting stability are critically examined and current design methods are compared. Data from UK mining tunnels are included as the basis for comparison of these design methods.

Jan 1, 1983

By J. M. Silliman

ISOMETRICAL drawing and clinographic projection are generally preferred to perspective drawings for representation of small objects or complicated mechanisms, as they present to the eye a sufficiently accurate picture of the object, while they possess great advantages over perspective in the simplicity and rapidity of execution, and the facility they give for taking measurements directly from the drawings.

Jan 1, 1882

By W. F. Wheeler

In the study of the coals of Illinois now being carried on by the State Geological Survey, an attempt is being made to determine the most satisfactory basis of comparison between different coals. The following discussion is based upon work done for the Survey in the laboratories of the State University and under the general direction of Prof. S. W. Parr. "Pure coal" has been defined by Mr. A. Bementl as ash- and moisture-free coal, and the use of this pure coal" as a basis for comparing different bituminous coals has lately been much discussed among engineers in the middle West. By some the B.t.u. of the pure coal is being used to check calorimetric results, and to calculate the calorific value of different coal-samples from the same seam, for which purposes it is necessary to assume—first, that the composition and calorific value of pure coal from different parts of the same coal-seam are uniform, and, second, that these values remain constant after the coal is mined, both of which assumptions there are reasons to believe are inconsistent with the facts. Certain variables are included in pure coal, as ordinarily defined, and disregard of them may lead to serious error. In any event, where delicate shades of difference are involved, no sure interpretation of results car] be made, unless these variables be eliminated. As a basis of comparison between coals, ash- and moisture-free coal is much to be preferred to " dry coal," and still more is it to be preferred to moist coal," as ordinarily reported in analyses. There are, however, two constituents other than ash

Jan 1, 1908

Manuscripts of Papers for Presentation at Arizona Meeting, Sept. 18 to 23, 1916, must be in hands of Secretary by July 1, 1916.

Jan 5, 1916

FIGURES covering appropriations recommended by the Budget Bureau for the Bureau of Mines at Washington for next year are now available and are as quoted below. APPROPRIATION BUDGET APPROPRIATION 1928 1929 General Expenses $ 86,000` $ 86,000 Investigating Mine Accidents 386,470 399,470 Mining Investigations in Alaska.. 10,860 10,860 Operating Mine Rescue Cars and Stations 327,630 342,630 Testing Fuel 154,000 158,500 Mineral Mining Investigations.... 99,570 125,000 Oil, Gas and Oil-Shale Investiga- tions 198,260 198,260 Oil-Shale Investigations 5,000 80,000 Expenses Mining Experiment Sta- tions 173,000 173,000 Care, etc., Buildings and Grounds, Pittsburgh, Pa 71,360 76,360 Maintenance and Operation, Fuel Yards Balance Balance Helium Investigations :.... 75,000 75,000 Helium Production and Conserva- tion 1,063,000 462.000 Potash Investigations 100,000 100,000 Economics of Mineral Industries. . 225,000 275,000 Totals $2,975,150 $2,562,080

Jan 1, 1928

By W. L. Crentz, E. E. Donath, D. Doherty

IN 1948, the United States used nearly six million barrels of petroleum products every day. Although substitution of synthetic fuels for the natural petroleum product is not here yet, large quantities of special-purpose coal will be required in ever-increasing volume as the domestic production of oil from other sources fails to meet demand and the production of synthetic fuels begins. Petroleum economists do not agree as to when the shortages of domestic oil will appear; but the increasing per capita consumption of oil, coupled with a constantly growing population drawing on a potential domestic oil supply estimated to be 85 billion barrels, sooner or later will result in demand exceeding domestic supply. When this situation comes about, the excess demand will be either eliminated by curtailment of consumption or the demand met by increasing importation of foreign oil or by the production of synthetic fuels. The first recourse would definitely retard the heretofore unbroken rise in American living standards, while dependence upon a foreign oil supply during a war or other emergency would be dangerous. On the other hand, the enormous coal reserves in the United States, plus sizable deposits of oil shale, indicate adequate means of augmenting a diminishing domestic oil supply. Some idea of the impact of an expanding synthetic liquid fuels program on the coal-mining industry may be gathered when it is considered that to supply just half of our present-day petroleum needs synthetically from coal would increase the coal output by about 500 million tons annually, using an 11,900 Btu bituminous coal as the plant feed. If either a subbituminous coal or lignite were used, the quantity required would be materially increased. Synthetic Fuel Processes: The principal synthetic fuel processes using coal as a raw material are the Bergius, or coal-hydrogenation process, and the Fischer-Tropsch, or gas-synthesis process. These two processes not only produce different end products, but the preparation of the coal used in each presents its own individual problem to the coal-preparation engineer. The hydrogenation process brings together a mixture of dry, finely powdered coal, catalyst, and heavy oil to form a paste. Addition of hydrogen under rather high pressure and temperature conditions brings about transformation of the coal to a liquid product, from which a high-grade gasoline and other motor fuels may be obtained. The Fischer-Tropsch process requires the production of synthesis gas, a mixture of carbon monoxide and hydrogen. At the Bureau of Mines Louisiana, Mo., demonstration plant, this gas is being made by reacting dried pulverized coal with carefully controlled volumes of oxygen and superheated steam. After purification and in the presence of the proper catalyst and suitable conditions of pressure and temperature, the hydrogen and carbon monoxide components of the synthesis gas react to form motor fuel. The two processes are not competitive but rather com-

Jan 1, 1951

By E. E. Donath, W. L. Crentz, D. Doherty

IN 1948, the United States used nearly six million barrels of petroleum products every day. Although substitution of synthetic fuels for the natural petroleum product is not here yet, large quantities of special-purpose coal will be required in ever-increasing volume as the domestic production of oil from other sources fails to meet demand and the production of synthetic fuels begins. Petroleum economists do not agree as to when the shortages of domestic oil will appear; but the increasing per capita consumption of oil, coupled with a constantly growing population drawing on a potential domestic oil supply estimated to be 85 billion barrels, sooner or later will result in demand exceeding domestic supply. When this situation comes about, the excess demand will be either eliminated by curtailment of consumption or the demand met by increasing importation of foreign oil or by the production of synthetic fuels. The first recourse would definitely retard the heretofore unbroken rise in American living standards, while dependence upon a foreign oil supply during a war or other emergency would be dangerous. On the other hand, the enormous coal reserves in the United States, plus sizable deposits of oil shale, indicate adequate means of augmenting a diminishing domestic oil supply. Some idea of the impact of an expanding synthetic liquid fuels program on the coal-mining industry may be gathered when it is considered that to supply just half of our present-day petroleum needs synthetically from coal would increase the coal output by about 500 million tons annually, using an 11,900 Btu bituminous coal as the plant feed. If either a subbituminous coal or lignite were used, the quantity required would be materially increased. Synthetic Fuel Processes: The principal synthetic fuel processes using coal as a raw material are the Bergius, or coal-hydrogenation process, and the Fischer-Tropsch, or gas-synthesis process. These two processes not only produce different end products, but the preparation of the coal used in each presents its own individual problem to the coal-preparation engineer. The hydrogenation process brings together a mixture of dry, finely powdered coal, catalyst, and heavy oil to form a paste. Addition of hydrogen under rather high pressure and temperature conditions brings about transformation of the coal to a liquid product, from which a high-grade gasoline and other motor fuels may be obtained. The Fischer-Tropsch process requires the production of synthesis gas, a mixture of carbon monoxide and hydrogen. At the Bureau of Mines Louisiana, Mo., demonstration plant, this gas is being made by reacting dried pulverized coal with carefully controlled volumes of oxygen and superheated steam. After purification and in the presence of the proper catalyst and suitable conditions of pressure and temperature, the hydrogen and carbon monoxide components of the synthesis gas react to form motor fuel. The two processes are not competitive but rather com-

Jan 1, 1951

By W. K. Hartley

INTRODUCTION AND HISTORY The Kimberley Division of De Beers Consolidated Mines Limited includes four underground mines in Kimberley viz. Dutoitspan, Bultfontein, De Beers and Wesselton Mine and two outside mines, viz. Finsch, an opencast operation and Koffie- fontein, an underground operation. Figure 1 is a map of the Kimberley district showing the location of these mines. Finsch is 150km west of Kimberley and Koffiefontein is 80km south of Kimberley. The head office of the De Beers Company is in Kimberley. The diamond sorting and trading companies for diamonds produced in South Africa are also in Kimberley. Diamonds were first discovered in the Kimberley area at Hopetown in 1866 on the banks of the Orange River. This, and later finds, triggered the start of the great "Diamond Rush". In 1870 the Jagersfontein (now closed) and Dutoitspan pipes were discovered, followed by those at Bultfontein, De Beers and Kimberley Mine (now closed) in 1871, Koffiefontein in 1880 and Wesselton in 1891. Finsch Mine was a more recent discovery in 1961. Finsch, due to go underground in 1986, and Koffiefontein, are fully self-contained with their own treatment plants, housing, services etc. The four Kimberley mines deliver ore by conveyor to a central treatment plant and use joint ser- vices. ,+lining is presently carried out mainly by Block Caving which has replaced the earlier Chambering method. De Beers Mine, on a limited scale, and Wesselton Mine have recently started to use Sub-Level Caving, and both Bultfontein and Du- toitspan are scheduled to use the same method at a later date. The combined ore tonnage produced by the Kimberley Mines is 17 400 tons per day, Koffiefontein 12 000 tons per day and Finsch Mine 17 000 tons per day. THE EVOLUTION OF MINING METHODS Initially, the open-cast mining was carried out to as great a depth as safety would permit. In the early stages of open-cast mining, the Kimberlite was removed in horizontal slices from levels 13m to 20m apart. The rock broken in the workings was raised to the surface by means of endless rope haulage inclines. As lower levels were attained these rope haulages were replaced by aerial hoists, inclined shaft haulages or inclined skip-ways. These methods were dependent upon the strength of the unsupported pipe walls, which became increasingly unstable with depth and a system was adopted whereby the ground mined in open excavations was tipped down passes to tunnels connecting with vertical hoisting shafts sunk in the country rock. As work in the open pit became more and more impracticable due to extensive falls of ground, this system was replaced by a combination of open-cast and underground mining, and eventually by wholly underground methods. Chambering With the advent of underground mining, a system known as "Chambering" (or "Inclined Chambering") was evolved. It was essentially a combination of shrinkage stoping and caving, whereby advantage was taken of the high pressure exerted by the loose rock that had accumulated in the open excavations due to the collapse of the pipe walls. This mining method was introduced around 1890 and was successfully employed, with little change, up to the early nineteen seventies. In this system each mine was served by a main hoisting shaft situated about 300m in the country rock. Main haulage cross cuts were driven from the shaft to the pipe at 200m (600ft) vertical intervals. A sub-vertical shaft, situated close to the pipe provided access to the working levels. Chamber levels were established from the sub-vertical shaft at 13m (40ft) intervals. See figure 2. On each of these levels successive 6,8m wide “cuts" were mined out across the pipe, from one rock contact to the other, and extended vertically to the footwall of the level above. Every 6,8m cut was made up of a chamber and a "back-pillart1, each approximately 3,401 wide. The chamber was mined by overhand shrinkage stoping. The levels were carried "en echelon", with each chamber on a level approximately three cuts ahead of the chamber on the level

Jan 1, 1981

By Earl Kennedy

The Northern West Virginia Region of Consolidation Coal Company consists of ten underground mines. The Pittsburgh seam of coal is being mined. This seam is approximately seven feet in thickness in our area. The mining equipment consists of twelve longwall systems and a combination of Joy and Jeffrey ripper type miners. There are a few boring type machines still in use, but these are rapidly being phased out. The auxiliary ventilation fans being utilized vary in type from single stage carriage mounted 20 horse-power Joys to 40 and 50 horsepower two-stage Joys, Buffalo Forge, and Peabody brands. The particular fans that we have primarily been working with on noise reduction are the two-stage 40 and 50 horsepower types.

Jan 1, 1982

By Clyde Longyear

DURING the last two years, the diamond core drill has come rapidly to the front as a very valuable auxiliary to the equipment of the exploration and production departments of oil companies. The diamond drill and the rotary oil drill work on the same general principles, the essential difference being that the diamond drill employs an annular steel bit set with black diamonds ("carbons"), instead of the fish-tail or other type of bit employed by the rotary drill. On account of the brittleness of the carbon and the danger of breakage if subjected to sudden blows or stresses, it is not practicable to attach a diamond bit and core-barrel to the end of a rotary drill stem. The operating mechanism of the diamond drill must be subject to much more sensitive control than the rotary drill. The bit must be rotated smoothly, without the jerks that are incident to the operation of the clutches and chain drives on the rotary draw works, and the feed must be con-trolled in a much more delicate manner than the mere action of a brake on a hoist. To accomplish this smooth rotation, diamond drills are usually built as a self-con-tained unit with the crank shaft of the engine geared direct to the drive shaft that turns the drill rods or stem. One or two hydraulic cylinders connected with a high-pressure pump control the feed so definitely that the bit can be raised or lowered at will, while the bit is rotating, by the simple operation of valves. The smaller-sized-drills for very shallow work usually have a screw feed control instead of the hydraulic feed. The principal uses of the diamond drill in oil work are three: 1. Reconnaissance or structure drilling; that is, the drilling of a number of shallow holes to ascertain the subsurface contour. 2. Scout drilling, or the drilling of holes of smaller diameter than is required for production, to obtain information as to the character of the oil sand and the quality of the oil. 3. Drilling producing wells.

Jan 5, 1923