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By Frederick H. Williams

THE object of this paper is to bring to the attention of those members of the Institute who are interested in the subject, a method for the estimation of manganese, which has been frequently used in the laboratory of the Vulcan Steel Works during the last eight months, and which is deemed worthy of more general use. It is simply an adaptation of well-known processes, for the purpose of determining this element in pig iron and steel. In general, the method consists in precipitating the manganese as binoxide, dissolving in dilute sulphuric acid in the presence of an excess of a standardized solution of oxalic acid, and titrating the remainder of the oxalic acid left unoxidized with permanganate of potash. For this method, therefore,. two standardized solutions are needed, viz., a permanganate solution and an oxalic acid solution. The permanganate solution is made so that 1 c.c. is equivalent to 1 mgr. of iron. By using so weak a solution and keeping the bulk of the solution to be titrated down to 75 c.c. or a little less, the accuracy of the process is greatly increased, since the final reaction is almost if not quite as sharp as if a stronger solution were used. The oxalic acid' may be of almost any strength, but if made so that 1 c.c. requires 3 c.c. of the permanganate to oxidize it, it will auswer well. The process is then, as follows : from 1 to 2 grams of pig iron or steel are dissolved in 40 to 50 c.c. of concentrated nitric acid with the aid of heat. As soon as solution is effected, in the case of steel, add gradually and cautiously, the solution being kept boiling, sufficient pulverized chlorate of potash to precipitate the manganese as binoxide. Two grams will be a great abundance. In the me of pig iron, first remove the carbon and silica by filtering the solution through asbestos and washing with concentrated nitric acid. Filter the strong acid solution in which the binoxide has been precipitated, through asbestos with the aid. of the filter pump. When it has entirely passed through wash well with water. Blow the contents: of the funnel into the beaker in which the precipitation was made and rinse the funnel with a little water.

Jan 1, 1882

By C. V. Milikan

Allocation of allowed production in a prorated field by the use of bottom-hole pressures is a method which is sound in theory. Thus far it has had limited application because the experience in correlating bottom-hole pressures with the depletion of wells or fields is not sufficient to interpret all the pressure changes. With additional data and more general knowledge of bottom-hole pressures their use in proration will probably become common. Bottom-hole pressure is the pressure at or near the bottom of a well. It is usually determined at the face of the producing horizon. Bottom-hole pressure measured while the well is producing, may be called the bottom-hole producing pressure or bottom-hole flowing pressure. If the well has been shut in or shut down long enough for the pressure in the producing horizon within the drainage area of the well to equalize, it may be called the reservoir pressure. The allowable production from a prorated field may be allocated to the individual wells or leases by three methods: 1. Bottom-hole producing or flowing pressures. (a) The potential capacity of a well to produce. (b) A uniform differential pressure while producing at the allowed rate. 2. Reservoir pressures. 3. A combination of bottom-hole producing pressures and reservoir pressures. In most prorated fields the allowed production is allocated to the individual wells or leases in proportion to their individual potentials. This method is based on the theory that there is a direct relationship between the permeability and the porosity of the reservoir. More directly stated it means that there is a direct relationship between the amount of oil in the reservoir and the rate at which it will move through the reservoir. While in general this relationship is true, it may vary considerably in different wells. Furthermore, in many wells the capacity of the reservoir to deliver oil to the well is greater than the capacity of the flow string to deliver oil to the surface. It is especially true where the potential is determined by flowing through tubing or by pumping.

Jan 1, 1933

W. ROWLAND Cox,* New York, N. Y. (written discussion?).-The process described by Mr. Malcolmson undoubtedly represents a great stride toward conservation of our natural resources. Without discussing the subject from an economic standpoint, I wish further to emphasize the fundamental principles of the Smith process in order that its economic value may be fully appreciated. The process is essentially a means of producing an ideal fuel, as regards its combustion qualities, by the removal of the so-called volatile matter from the coal, in the form of byproducts, which have value for other purposes far in excess of their fuel value. In other words, coals which contain. large amounts of gas, tar, and ammonia, and are not suitable for domestic or industrial fuel, or for treatment in byproduct coke ovens or gas retorts; because they possess poor coking qualities, can he prepared for commercial use by the. Smith process with a very high degree of efficiency. Much work has been done along this line, both in this country and in Europe, in developing a means of preparing coal, as the economic advantages have long been recognized. To the best of my knowledge, the Smith process is the only one that has proved its commercial adaptability. Distillation of coal at 900° to 1000° F. (480° to 540° C.) yields a large amount of tar and oils. The residue of the distillation, however, is a very friable semi-coke, wholly unsuitable for use as a fuel, unless it can be charged directly into a byproduct gas producer. The problem which confronted the inventor was then to convert this carbon residue into a commercial product, and it is in this step that the Smith process has overcome the obstacles which prevented a number of other methods from becoming commercially practicable.

Jan 10, 1918

By John Reynders

Our entry into the World War suddenly brought home to us in a startling way the vital importance of manganese. Since the war, much has been written and said upon the subject of manganese and a great deal of time and money have been spent in attempts to find an adequate substitute for this metal in the manufacture of steel; none has been found. It is true that ways are known by which it is possible to make small amounts of good steel without manganese; but taking into consideration the diminishing quality of iron ores and fuels. as' well as the increasing exaction of specifications for finished products, it may safely be assumed that high-grade manganese ore will be more and. more a necessity in the production of steel as time goes on. Taking world resources as a whole it may be well to point out that the problem of obtaining needed supplies of manganese from a strictly commercial viewpoint is now less serious than it was before the war. Formerly it was feared that world resources of high-grade manganese ore might be exhausted in a relatively short time, but, largely as a result of the stress laid upon the importance of manganese during the war, the world's available supply of high-grade manganese ore has been greatly augmented by new discoveries and fuller development of previously known deposits.

Jan 5, 1927

By Walter M. Small

Austria produced approximately 800 cisterns of 10,000 kg. each (56,000 bbls.) of crude oil of a 0.9428 sp. gr. during 1935. Of this Gosting II well near Zistersdorf, owned by the Erdolproduktions-Gesellschaft m.b.H., produced 86 per cent of the total, averaging a little over 1.8 cisterns, or about 125 bbl., per day. Gosting IVa of the same company was put in production early in December and produced a total of about 70 cisterns (4900 bbl.). Gosting IV was a failure, but a directional hole drilled from the same derrick produced Gosting IVa. Gosting I, a well owned jointly by the company above mentioned and the Raky-Danubia, was deepened late in the year and made about 2800 bbl. of oil at the rate of 70 bbl. per day. Completions during the year were as follows: In the Gosting pool, Gosting IV and IVa, drilled with rotary tools, the latter producing from Sarmat at a depth of 934 meters (3065 ft.); Kronberg I, of European Gas & Electric Co. with cable tools in Flysch at a depth of 566 m. as a dry hole; in the Oberlaa gas pool, one cable-tool well of the same company at a depth of 266 m. as a dry hole and one Fauck-Haiek system well of the Vacuum Oil Co. at a depth of 483 m. as a dry hole; one rotary hole of the European Gas & Electric Co. at Enzersdorf a/d. Fischa plugged and abandoned in Sarmat after a blow out and gas eruption at a depth of 699.5 meters. The status of drilling wells at close of the year is as follows: In the Gosting pool, Erdol Bohr- und Verwertungs G.m.b.H., north of the producing area, was drilling with rotary at 990 m., Raky-Danubia is rigged up to deepen the old Windisch-Baumgarten hole, Rohoel-Gewin-nungs A.G. (Vacuum-Shell combination) rigging up rotary south of the production, and Steinberg-Naphta G.m.b.H. (Musil) was deepened with light rotary to 830 m.; at Enzersdorf a/d. Fischa, the European Gas & Electric Co. E-2 rotary-drilled hole stood at 1533 m. in Miocene waiting

Jan 1, 1936

By Warren B. Weeks

Continued development in the deeper fields discovered during 1937 and 1938 was largely responsible for the 16 per cent (2,913,400-bbl.) increase in production, bringing the 1939 output to 21,376,230 bbl., the largest for South Arkansas since 1929. The older settled fields continued to decline and Rodessa was added to this classification. Magnolia field accounted for much of the increase, with Schuler field showing only a slight increase. There were 248 wells drilled during 1939, five more than during the previous year. Of 198 wells drilled in proven fields, 21 were dry; 46 of the 50 wildcats drilled were dry. The old depth record of 8332 ft. was increased to the present record of 9028. Trend of Prospecting Production from the porous " Reynolds " oolite zone of the Smackover limestone continued to be the objective of prospecting. During the year 20 seismograph, 3 gravity meter, 1 magnetometer, 1 soil analysis and 1 electromagnetic crews were reported in the state. The geophysical work was largely concentrated in three southern counties: Columbia, Lafayette and Union. As indicated in Table 2, the same three counties received most of the important drilling tests. At the end of the year only three seismograph crews remained in the areas. The area for prospecting Smackover limestone was greatly narrowed during the year by the failure of two "fault zone" wells to find satisfactory permeability in the oolite zone, and by the relatively thin sections of porosity found in wells drilled in townships 18 and 19 South. Geology Most of the wells listed in Table 2 afforded additional control on structure of the lower beds, but gave little new information on stratigraphy. Of the 248 wells drilled, 3 ended in Tertiary, 34 in Gulf, 1 in Paluxy, 29 in Glen Rose, 15 in Travis Peak, 15 in Cotton Valley, 139 in Smackover, 2 in Eagle Mills and 10 in Carboniferous. The age of the beds between the Travis Peak formation and Carboniferous is still questionable. Most

Jan 1, 1940

Oceanographers are tooling up. Back of the build-up is Navy defense work and private business. Business is dipping toes in the ocean gingerly and not sure whether the motivation is based on logic or intuition. The problem is that new business opportunities in the oceans could explode rather than evolve. The question is when. At stake for earthlings are food supplies, mineral resources, oil and gas, weather forecasting, navigational systems, shore erosion control and sewage disposal, as primary targets. "Twenty years ago, offshore oil seemed a remote possibility for economic exploitation but today it is a reality. It became a reality largely because of the development of practical ocean seismic equipment and drilling platforms. Today the oil industry is looking at submerged-type drilling rigs. Mineral exploration in the sea is more expensive than on land now primarily because familiar land tools are being modified for sub- marine work." These were the ideas expressed by C. G. Welling of Lockheed Missiles & Space Co., at one of the many meetings that have taken place so far this year on development of marine resources. Welling's views indicate the rationale of companies that have already invested in the sea. Many companies, including those in mining, have observers who caution, "go slow." The continental shelfs and even the deep ocean floor represent to the mineral industries the age-old, enigmatic confrontation-is this the time to move? To no other industry, except Defense, are the results of correct timing so vital.

Jan 8, 1967

By Claude H. P. Lupis, John F. Elliott

The classic Siez~erts' technique has been employed to determine the solubility of oxygen in liquid pure silver and the effect on the oxygen solubility of solute metal additions to liquid silver. The results indicate that oxygen deviates slightly from Sieverts' law in pure silver as = 3.9. Gold, platinum, md palladium decrease the solubility of oxygen in silver. First-order free energy, enthalpy, md entropy interaction coefficients are determined from the data. An important aspect in the establishment of the formalisms to be applied to represent the thermody-namic behavior of components of solutions is the accuracy of the experimentally determined thermody-namic properties. Wagner developed the first-order free energy interaction coefficient.' Recent papers2'3 extend the treatment formally to other thermodynamic properties and define the second- and higher-order interaction coefficients. A current communication4 considers in some depth the requirements and limitations imposed because of experimental error on the use of several formalisms now under active consideration in the field. This communication reports the results of an experimental study of the behavior of oxygen in liquid silver alloys that was carried out concurrently with the development of Refs. 2 and 3 with the hope of providing sufficiently precise information so that enthalpy and entropy interaction coefficients could be determined. THE EXPERIMENTS The Sieverts technique was employed using an improved design of the reaction bulb over that developed originally by Humbert5 and subsequently improved by pehlke6 and Weinstein.7 The Vycor reaction bulb as shown in Fig. 1 was air-cooled and contained a port for the thermocouple angling off to one side and a vertical port for connections to the gas supply and

Jan 1, 1969

By E. W. Owen, John G. H. Crump, Peter P. Gregory

A noticeable decrease in activity characterized the year 1938 in the West Texas area. The total number of wells completed dropped to 2045 for 19381 as compared with 2806 completions in 1937,l a decline of 27.12 per cent. This trend contrasts the sharp increase of 76.29 per cent in completions in 1937 over the 1936 total. Of 2045 well completions during 1938,' 1788 were oil wellsll 16 were gas producers1 and 241 were listed as failures.' During 1938 the ratio of dry holes drilled to oil-producing or gas-producing wells completed was one dry hole to each 7.48 oil wells, which compares with one dry hole drilled to each 7.477 oil wells in 1937. Nearly 200 wells drilled during 1938 in West Texas were either wildcat or partly wildcat wells, an increase of about 25 over the year 1937, when approximately 175 wells drilled were so classified. The 200 exploratory wells drilled represent about 10 per cent of the total number of wells completed. West Texas produced 71,257,541 bbl.1 of oil in 1938 as compared with 75,743,000 bb1.2 of oil in 1937, a decrease of 4,485,459 bbl., or a 5.92 per cent decline. By comparison, West Texas produced 22.36 per cent more oil in 1937 than during 1936. In December 1938, the 9247 producing oil wells in West Texas1 averaged 22.08 bbl. per day per well as compared with December 1937, when 7571 wells1 produced an average of 25.18 bbl. per day per well, or a decline in daily well average of 12.32 per cent. Discoveries No outstanding new fields were discovered in West Texas during 1938, in spite of continued, active wildcatting operations. Several new oil-producing areas were, found, however, the value of which is still unknown.

Jan 1, 1939

By O. H. Hahn

I have lately had occasion to conduct a campaign at the works of the Empire City Company, in Railroad District, Elko County, Nevada, which, if not highly satisfactory, was at least very interesting in a technical point of view, and which I therefore think worthy of communication to the Institute. The lead ores in this district occur in lenticular masses along and near the contact of crystalline limestone with a dioritic porphyry, and consist of argentiferous carbonate of lead and galena, the latter occurring in solid blocks, or in ribbons running through the limestone. Associated with these are silicate, carbonate, and suboxide of copper, and brown and calc-spar. Adding to this, that the proportion of galena in the ore is small, and that no iron pyrites exists in the district, it is at once evident that the ore-mixture is difficult to treat. For a successful reduction by smelting, it would be necessary to introduce into the charge: 1. The proper quantities of sillphur-bearing ingredients, to effect a complete separation of copper and lead; and, 2. Sufficient silica and iron oxide, to form with the lime and magnesia of the ore, a slag of the required fluidity. The first condition could be fulfilled only very imperfectly, there being no iron pyrites in Railroad, nor in the surrounding districts. The nearest occurrence is in Battle Mountain, whence a supply could not be procured in time. The second condition, i. e., the addition of iron ore and quartz, was easily complied with, there being an abundance of these materials in the vicinity. The furnace of the Empire City Company, is a small shaftfurnace, with an area of hearth of six square feet, and is supplied with blast by a NO. 4 Root blower. In spite of this small size the furnace smelted during this campaign, which lasted 31 days, an average of 28 tons of ore, and 13 tons of fluxes, together 41 tons of charge, per twenty-four hours. The following tables give the complete data in regard to the smelting process, and the results obtained:

By John W. Roberts

The Federal income tax law permits as a deduction in determining net income "in the case of mines,... a reasonable allowance for depletion and for depreciation of improvements, according to the peculiar conditions in each case, based upon cost, including cost of development not otherwise deducted: Provided, that in the case of such properties acquired prior to Mar. 1, 1913, the fair market value of the property (or the taxpayer's interest therein) on that date shall be taken in lieu of cost up to that date." The law provides for a reasonable allowance but the regulations provide for a definite method of computation that possesses more the virtue of simplicity than that of reasonableness. Article 210 of Regulations 45 reads: "When the cost or value as of Mar. 1, 1913, or within 30 days after the date of discovery of the property shall have been determined, and the number of mineral units in the property as of the date of acquisition or valuation shall have been estimated, the division of the former amount by the latter figure will give the unit value for purposes of depletion, and the depletion allowance for the taxable year may be computed by multiplying such unit value by the number of units of mineral extracted during the year." This is simple, but is it reasonable? The intent of the law is clearly that the cost of the ore in the ground shall be considered as part of the cost of the same ore when removed and sold. The regulations fail to carry out that intent, because of the unwarranted assumption that all the ore in the mine cost the same amount per ton. This is what gives the Treasury Department's method its simplicity, but at the same time robs it of its reasonableness because the assumption is contrary to fact. It is self-evident that a ton of ore near the surface or exposed by present workings is worth much more than a ton buried so far down in the earth that it cannot be removed for many years. If no improvements in mining methods were expected, the value of deeply buried ore would be further reduced by the greater expense that would be required to

Jan 1, 1922

By P. R. Sheorey

I read this interesting paper on pillar strength in some detail because this is also my area of interest. It has long been the desire of mining rock mechanicians to predict pillar strength from laboratory compression tests. Considerable literature is available on compression strength of rocks and coal but many of these experiments were conducted not for pillar design but for rock behavior. I have a few comments on the author's approach to pillar design, especially equation (33). Two important factors, which the author seems to have excluded, can be added to the right side of equation (2): time-dependence of strength and the influence of mine environment on strength (moisture and weathering.) The author has taken considerable pains to analyze a large amount of testing data in [Table 1], yielding the various exponents ci of equation (2) (or the subsequent equations derived from it.) He has, however, not shown by means of a worked out example how these values of [Table 1] could be applied to a practical pillar design situation. It would have been interesting to compare predicted pillar size using equation (33) with an actual case. Alternatively, equation (33) could have been used to explain the failure of a pillar, if such a case history were available. Consider we have a large number of case histories of stable and collapsed pillars in a seam and we conduct a large number of tests in a laboratory press. The exponents [ci] can then be determined for actual pillars as well as for test specimens. Thus, equation (2) will read [ ] Since laboratory testing conditions (e.g., between steel platens) are different from the conditions on pillars, the exponents [ci] in

Jan 1, 1983

By Samuel Wyer

F. G. CLAPP, New York, N. Y. (communication to the Secretary*).¬I assume that where this valuable paper states, near its end, that "it is not possible to establish a market price, " the author means that no particular price which will fit all conditions and fields can be given. I am not in agreement with Mr. Wyer, however, that the actual value of natural gas leaseholds is "largely a matter of opinion." I would even be willing to express myself very strongly as believing that if we, as experts, cannot give anything closer than a mere opinion, our testimony or reports are not of great value to our clients. I believe, moreover, that by detailed geological examinations and with our latest knowledge of geological structure, principles of natural gas occurrence, etc., we can approach just as near a certainty in natural gas valuations as we can in oil valuations, and much more so than in the valuation of many metal prospects, in which only the upper few feet of the vein has been opened. In other words, we are getting nearer and nearer every year to bringing geology as applied to oil and gas development into the class of an exact science. Mr. Wyer's paper gives an excellent outline for methods of leasehold valuation. Being presumably intended as an outline only, it can be expanded indefinitely by a detailed discussion of the methods of valuation for the four different classes of leaseholds which he mentions: (A) "Producing;" (B) "Protective;" (C) "Reserve;" and (D) "Prospective." This classification is probably as good as can be made in practice. In the producing leaseholds in particular it is easy to establish a market price at which these leaseholds should be bought or sold. The question would arise in any case whether or not the leases are connected with a pipe line or the distance from the pipe line. Assuming that a pipe line already taps the property and that gas is already being sold for a certain figure, this price must be multiplied by the number of thousand cubic feet still "in sight" in the ground, from which is to be deducted (a) bonuses, (b) rentals, (c) royalties, (d) cost of drilling, (e) taxes and

Jan 12, 1916

By Walter Miller

Any annual review of engineering progress in petroleum refining must of necessity include many features mentioned in earlier reviews. Advances do not spring mushroom fashion to wide acceptance overnight, but rather resemble rolling snowballs, gathering size and velocity as they progress. The new ideas of one year develop through the course of scattered adoption and testing during following years, to be ultimately discarded or to become an integral part of refinery engineering and operation. Polymerization and Cracking As an illustration, the publicity given to the polymerization and cracking of petroleum gases during the year has given many the impression that this is a new art. But patent and technical literature have disclosed active work on the problem dating back a decade or more and a unit capable of making 100 bbl. a day of polymer gasoline was constructed as early as 1930. Important strides have been made during 1935 looking to the more general commercialization of available processes, and some four important groups are furthering this work. In addition to the production of liquid products for inclusion as a constituent of commercial motor fuel, polymerization has also been a factor leading to the installation of a plant at the Houston refinery of The Shell Petroleum Corporation for manufacturing isooctane for aviation use, by making available dibutylene for catalytic hydrogenation Polymerization is not confined to unsaturated hydrocarbon gases as a source of raw material, and has been extended to include a preliminary decomposition of normal saturated gases under suitable heat and pressure conditions into the unsaturated types, which can then be used as raw material for the polymerization process. Thus there is opened up the possibility of eventually using large quantities of natural gas in the manufacture of high-grade motor fuels, although the early commercial growth will be largely on cracking still gases for economic reasons. Such utilization will result in a somewhat lowered drain on crude-oil reserves and a partial elimination of the

Jan 1, 1936

By Leonard Larson

DURING several years immediately preceding the adoption of wet-charge smelting at McGill, various necessary conditions affecting this procedure, such as plant rearrangement and the metallurgical nature of the concentrate produced at the concentrator, were fully considered. Wet-charge smelting is not altogether novel to the recently reconstructed smelter at McGill. A number of years prior to this improvement, when flotation methods were initiated at the concentrator, large tonnages of wet and (at that time) sticky flotation concentrate were charged directly into the reverberatory furnaces, because of the difficulty in handling the entire tonnage in the roasters. The plant had excess reverberatory units and this surplus furnace capacity was utilized to smelt raw flotation concentrate. During the years 1927 and 1928, a number of actual operating furnace test runs were made to determine in principle the feasibility of wet-smelting operation. Results were encouraging, and in November 1932 the roasting plant was shut down. For some time thereafter the wet feed was delivered directly to the reverberatory side-charging calcine hoppers already in place. Feeding the wet material through the old calcine hoppers and charge holes into the furnace involved considerable labor, but under the conditions existing at that time it was desirable to continue wet smelting even under the handicap of this laborious procedure. The smelting plant during this period was on a curtailed production basis, operating only about 15 days per month. The alternate starting up and shutting down of the roasting plant presented a difficult problem and charging the wet material directly to the furnace entirely eliminated this difficulty. The roasting plant was never operated thereafter. EARLY PROCEDURE Fig. 1 shows the general layout of the smelting plant before the smelter was remodeled. Under this arrangement, all concentrates and fluxes except converter flux were delivered in cars to wooden storage bins, which paralleled the roaster building. The material to be roasted was dis-

Jan 1, 1938

By Thomas W. Gibson

THE Province of Ontario in recent years has come strongly to the front as a producer of metals, especially nickel, copper, silver, and now gold. Of the last named, the output for 1922 was in the neighborhood of $20,000,000. The law governing the mining industry in a community where such develop-ments are taking place will be of interest, therefore, in other places where mining laws are up for revision The first mining of importance done in this province was for copper on the north shore of Lake Huron, where the Bruce mines were opened in 1846. These deposits of copper sulfides, notwithstanding the remoteness from markets and the cost of transportation, were vigorously worked for 12 or 15 years and also intermittently later, but the active career of the mines came to an end in 1875. From first to last, a little less than 10,000 tons of copper was produced, valued at $3,300,000. All the product was shipped to England as dressed ore, contain-ing up to 13 per cent. of the metal. In. 1866, a rich pocket of gold was found on the Richardson farm near Madoc, Hastings County, but was not followed by further discoveries of a like kind and in time the excitement it caused died away. Rich silver ore was found in 1868 on Silver Islet in Lake Superior, a speck of land not larger than a good-sized ball-room. The assemblage of minerals here was practically the same as that at Cobalt, discovered 35 years later, namely, native silver, cobalt, nickel and arsenic; in addition, there was considerable argentite, which has always been scarce at Cobalt. In all, the silver produced amounted to about $3,500,000. The belief persisted that the deposit was not mined out, and in the summer of 1922, some rich ore was extracted from the roof, perilously near the bottom of Lake Superior.

Jan 2, 1923

By F. W. Metzger

INTRODUCTION Coal quality control in mining and mine planning has always been important and has become even more essential in recent years due to environmental considerations. The primary consumers of the sub-bituminous coals found in the Powder River Basin are electric utilities that require low sulfur coals to meet government air quality regulations. Electric generating plants are designed to burn coal of a specific quality, and the supplier of that coal must be able to guarantee shipments within specified quality tolerances. Over the past several years, Exxon Coal USA and, more recently, The Carter Mining Company, a division of Exxon Coal USA, have established an evaluation and development program to accurately define the geology and quality of their coal properties. This requires an adequate drill hole density so that detailed correlations of the coal seam and the lithologic units, or benches, within the coal seam can be made. These units are recognizable in the core and also on geophysical logs. Like any systematic approach, geologic modeling has been refined and improved through new technologies. Today, coal seam properties are mapped using computer applications. Rapid access and manipulation of these data allow for optimization of mining efforts. This presentation will demonstrate how a detailed mapping program can be important in both pre-mine development and in-pit quality control.

Jan 1, 1983

By Julianne H. Glarmaty, Peter J. Conroy

INTRODUCTION In 1970 the percentage of underground coal extraction by longwall mining methods in the U.S. was 2.1 percent. This figure rose to 4.4 percent in 1976 and is expected to rise to 12 percent by the year 1985. This figure represents 46.0 million tons (51.0 million st) of annual production (Kuti, 1978). In addition, OSM regulations are placing emphasis on subsidence prediction. Section 784.20 of the Office of Surface Mining regulations for underground mining permit applications requires the sutauission of a subsidence control plan which may include monitoring. Because of its nature, longwall mining does not have flexibility in leaving pillars under structures as does room and pillar. Mining in some areas, particularly in the Eastern Coal Field, is approaching more developed areas; therefore, a greater number of structures are expected to be undermined in the near future. Subsidence engineering is becoming an important aspect of mine planning, and should be directed at predicting potential structural damage. The question operators are increasingly faced with is "what will be the subsidence effects for a specific structure at a specific location in respect to a longwall panel?" The most significant variable in assessing the subsidence effect on structures is not vertical subsidence. The variables of strain and tilt are responsible for more structural damage than is the vertical movement. Table I presents threshold values of strain for various structures (Geddes 6 Cooper, 1962). Based on National Coal Board experience, horizontal strain is approximately inversely proportional to the radius of curvature of a circular portion of a subsidence profile; therefore, the radius may be useful in estimating the magnitude of strain caused by subsidence (Hoebs, 1982). The radius of curvature can be determined by the following equation:

Jan 1, 1982

By H. C. Spaulding

Every constructing engineer and designer knows how often it is desirable to provide a speed-adjustment between parts of a machine performing different functions, or between a prime mover and the devices to which it furnishes power, and how bulky and unsatisfactory are most of the methods by which the result is usually accomplished. Of course the step-pulley is the most simple and generally used. It requires, (1) parallelism of shafts; (2) a considerable distance between centers; and (3) a cessation of power during the change from one speed to another. Add to this the necessity for careful design in order to obtain equal belt-tension for all positions; the weight and hulk required for a wide range; and the operative's positive conviction that better results could be obtained at a speed intermediate between those furnished by two successive steps, and we begin to realize the mechanical shortcomings of this old and familiar friend. The hundred and one other devices, patented and otherwise, for accomplishing similar results, present other objections of varying importance, which need not be discussed here. Without pretending to overcome these entirely, and indeed without claiming absolute novelty, a recent invention of Mr. E. F. Gordon, of Dover, N. H., has seemed to the writer to offer such advantages in flexibility and range of application as to merit a more extended study and use than can be given in his own work, to which it is being applied as rapidly as opportunity permits. It is placed before the members of the Institute, not only to bring out an expression of opinion as to its limitations, but also with the hope that it will thus find opportunities for applications hitherto untried and outside the scope of operation of those at present interested in its development. Simply stated, the device consists of a narrow pulley with a deep V-groove, split by a plane passing through the bottom of the groove, one of the two symmetrical parts so formed being fixed to the shafts, and the second being capable of adjustment so as to bring the

Jan 1, 1893

By Richard J. Gowen

THE FUTURE The environment in which we live appears to change so slowly that most of us are unaware that any change has occurred at all. As the years pass, we notice increasing smog in our cities, new variations in weather, the shifting landscape with changing populations, and subtle but ever present alterations in the quality of life. In considering the future of our environment, we find we must grapple with questions concerning the very future of life as we know it today. Questions of resources, technology, society, governance, and purpose. Let us focus on the future of our environment and, in particular, raise the question of who is responsible for the environment. We know that action, or lack of action, will clearly influence our future environment. It is fashionable to catalog the many short-sightedness of our forefathers in developing the technologies which support the style of living to which we have become accustomed. However, I shall struggle to resist the temptation to list the well known ills of our present environment. Rather, let us concentrate on the future in our consideration of the priority of the multitude of options proposed to relieve our current energy crisis. We have recently witnessed the dramatic effects of air pollution produced by Mount St. Helen's eruptions. In the state of South Dakota, we watched our blue skies turn hazy and felt our eyes sting with the presence of volcanic ash. We were appalled at the dramatic effects on the landscape, crops, transportation, and all aspects of life in communities immediately downwind of the volcanic eruption. But in a few weeks, life had returned to near normal on the earth's surface leaving the volcanic ash in the atmosphere to ultimately

Jan 1, 1983