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By Breaux B. Castleman

The ultimate test of a business strategy is whether it achieves the owner's objectives. Most shareholders are interested in growth and profits, and share values on stock exchanges are very often closely correlated with profit growth and profitability measured as return on equity (ROE). Strategic management, then, involves managing investments or resource allocations to optimize long-term growth and real return on equity, within reasonable limits of risk. Figure 1 shows a plot of the five year, weighted average ROE of a number of communications companies against their stock market valuations in 1983, measured as a ratio of market value to book value. The principal explanation of the differences in the relative valuations of the individual stocks is historical ROE, weighted toward the most recent years. Further analysis demonstrates the added importance of growth in explaining the differences in stock market to book ratios. [ ] Research conducted by Booz Allen and others in recent years suggests that the relationships between ROE and market to book multiples hold true in industry after industry. Furthermore, we have found that in assessing business strategies for companies in these industries, the analyses should focus on whether proposed strategies are likely to lead to consistent long-term growth in real ROE, without excessive leverage. Our research also reveals, however, that these approaches to strategy assessment are not consistently applicable in the natural resource extractive industries. Figure 2 shows a similar comparison of market to book values against five year average ROE for a group of nine mining companies in 1983. Market value of the shares shows little correlation with ROE. [ ] Analysis of the data for other extractive industries indicates a similar pattern; that is, low correlation between share values and

Jan 1, 1985

By James Boyd

It is obvious that mining has been influenced to a high degree by political and economic events, many of which are of such a nature that the mining industry has relatively little influence in shaping them. I cannot present too optimistic a picture for the immediate future, although I feel that from the long-range standpoint one need not be pessimistic about the future of the mining industry. The population of the United States is continuing to increase and with it has come an expanded consumption of metals on a per capita basis. With this expansion there has and will continue to come the demand for more goods and in- creased products from our mines and our fabricating plants. World War

Jan 5, 1950

By J. C. Jaeger

The study of brittle fracture of rocks has been a much neglected subject until quite recently and now is in a state of transition and rapid development. Historically, three methods of testing were used by engineers: uniaxial tension, bending, and, by far the most common, uniaxial compression of cubes. This latter was probably adequate for engineering requirements, but from the last century onwards there has been a demand from geologists for a study of the properties of materials under conditions comparable with those at depth in the earth's crust. King1 remarked that "in engineering practice a cube of the material is put into a testing machine and the stress required to crush the cube is measured. This gives the limiting stress difference for the material so long as the boundary conditions are similar to those existing during the test . . . this may by no means be the case when the boundary conditions are very different from those existing in the test, for instance, in the case of rupture in the neighbourhood of a cavity. . . ." Despite this very clear statement of principle, many writers until recently (e.g. Jeffreys2 used the uniaxial compressive strength as a measure of the 'strength' of rock. In the last century (Becker 3, it was both conjectured and, for some rocks, known qualitatively, that plastic deformation could occur under confining pres- sure; the demand from geologists has been for the study of flow rather than fracture of rocks.. From the time of von Karman (1911) and Böker5 (1915) onwards, apparatus has been built which could provide confining pressures sufficient to make some rocks plastic. Many experiments tended to be made on rocks such as marble, which readily become plastic, and the general tendency was to make relatively few experiments in the brittle range. This is particularly true of many experiments on combined stresses. As a result of this, there is not sufficient data to provide adequate information

Jan 1, 1967

By Spruille Braden

My attendance at this seventy-fifth Anniversary banquet of the A I M E is for me a homecoming, It means renewing associations with old friends, breathing again 'the invigorating mining atmosphere in which I was born and reared, and being among those who remember with affection and esteem the man from whom I inherited a name so intimately linked to-the mining profession Tonight, like a prodigal son strayed from mining into the far countries of diplomacy, I return, to eat and be merry over the fatted calf on this pleasurable occasion , While there is no riotous living in modern diplomacy, you are no doubt convinced that neither did I suffer a mighty famine in those far lands When I entered the Foreign Service, a few mining friends, viewing diplomats as sartorial perfectionists, or "striped pantsers" preoccupied with the art of cookie pushing, no doubt thought me a lost soul Conversely, some of my new colleagues at first looked upon me captiously and later as a reformed character, because they believed all miners to be rough customers, attired in muddy boots and given to direct action and equally direct or even explosive speech In point of fact, these two professions have much in common I do not have in mind the parallel cynicisms that "a miner is a liar with a hole in the ground" and "a diplomat a man sent abroad to lie for his country " I do

Jan 1, 1947

By Graham John Mitchell

In May, 1919, a crosscut on the 1400-ft. level of the Briggs mine, a Calumet, & Arizona property at Bisbee, Ariz., penetrated a deposit of pyrite and chaleopyrite that had replaced quartzite and limestone and was cut, especially in the quartzite, by numerous fractures. As the drift advanced through these fractured portions, they were found to be free from copper-sulfate minerals although '(sooty" chalcocite was present in the fractures and also as coatings and replacements of pyritc. Howcver, sulfate soon made its appearance in certain fractures, filled them, and began to form stalactites. Several centers of incipient growth were noted for subsequent study, observations in the drift at frequent intervals during the past 17 months affording the opportunity of determining the rate of formation of the stalactites. The one to attain the greatest growth during the period of observation measured 27 in. long and averaged 1 in. in diameter. A close study showed it to be composed of small interlocked crystals of chalcanthite radiating from a small central tube-like opening. The trielinic form of the crystals was evident with prism and pinacoid faces recognixable. Assuming that the supply of copper-sulfate solution was constant (luring the 17 months—-and such an assumption is supported by the fact that the number of drops of excess solution falling, per minute, from the tip of the stalactite at the times of observation checked closely—thc stalactite, it has been estimated, grew at the rate of 1.58+ in. per month. DISCUSSION James I?. Kemp," New Yolk City.—J. S. Curtiss, in the monogr:tpll on Eureka, Ncv., say:: that a stalactite formed in limestonc grew 5/8 in. in three weeks and continued to grow as long as it had a drop of water or solution at the lower end. Another grew at the rate of 3/8 in. in the same time. In the case cited by Mr. Mitchell, the growth was about 136 in. in three weeks. A year ago we had an instance of the formation of cubes of galena on a railroad spike. A mine in northeastern Oklahoma had been idle about two years but on account of pumping of neighboring properties, the circulation of water was active throughout the drift. A cube of galena,

Jan 1, 1922

By Frank A. Herald

Through the generous cooperation of the authors of the papers in this chapter, a great wealth of fundamental data is being made available. The same plan of securing and submitting data will be carried forward next year, with the hope of making a nearer approach to complete presentation of the data contemplated in the plan. In order to conserve space, we are printing below such footnotes as have general application to Table 1 in the papers in this chapter: Footnotes to Column Headings Table I In areas where both oil and gas are produced, unless gas is marketed outside the field, such areas are included in column headed "Oil." Manufacture of casinghead gasoline and carbon black is interpreted as outside marketing of gas. Production per acre is determined by dividing into the number of barrels of oil the sum of the number of acres assigned to "Oil" plus such number of acres of the total assigned to "Oil and gas" as represents the portion thereof occupied by oil. Wells producing both oil and gas are classified as "Poducing oil only" unless gas from them is marketed off the lease. W. water; G. gas; A, air. Bottom-hole pressures are preceded by "e." All other figures represent pressures at casinghead with well closed. P, paraffin; A, asphalt; M, mixed. 0 Cam, Cambrian; Ord, Ordovician; Sil, Silurian; Dev, Devonian; Mis, Mississippian; MisL, Lower Mississippian; MisU, Upper Mississippian: Pen. Pennsylvanian; Per. Permian; Tri, Triassic; Jur. Jurassic; CreL, Lower Cretaceous; CreU. Upper Cretaceous; Eoc, Eocene; Olig, Oligocene; Mio. Miocene; Pli. Pliocene. 6, sandstone: SH, sandstone, shaly; Ss, soft sand; H, shale; L, limestone; LS, limestone. sandy; C, chalk; A, anhydrite; D, dolomite; Da. arkosic dolomite; GW, granite wash; P, serpentine. Figures are entered only for fields where the reservoir rock is of pore type. Figures represent, ratio of pore space to total volume of net reservoir rock expressed in per cent. "Par" indicates that the reservoir rock is of pore type but said ratio is not known by the author. "Cav" indicates that the reservoir rock is of cavernous type; "Fis," fissure type. A, anticline; AF, anticline with faulting as important feature; Af, anticline with faulting as minor feature; AM, accumulation due to both anticlinal and monoclinal structure; H, strata are horizontal or near horizontal; MF, monocline-fault; MU, monocline-unconformity; ML, monocline-lens; MC, monocline with accumulation due to change in character of stratum; MI, monocline with accumulation against igneous barrier; MUP, monocline with accumulation due to sealing at outcrop by asphalt; D, dome; Ds, salt dome; T, terrace; TF, terrace with faulting as important feature; N, nose; 9, syncline. Information will be found in text as indicated by symbols: A, name of author, other than above. who has compiled the data on the particular field; C, chemical treatment of wells; G, gas-oil ratios; P, proration; U, unit operation; R, references; W, water; 0. other information.

Jan 1, 1934

By R. H. Dourson, B. H. Sage, W. N. Lacey

The compositions of coexisting phases in the methane-propane-n-pentane system were determined at 160° and -2 20°F. throughout the two-phase region, at pressures above 500 lb. per sq. in. The experimental results permitted the calculation of gas-liquid equilibrium constants as well as the establishment of the critical behavior of this ternary system. Although many binary paraffin hydrocarbon systems have been investigated, the experimental work relating to the phase behavior of ternary paraffin hydrocarbon mixtures at elevated pressures is relatively scarce, being limited to a study of the meth-ane-propane-PL-pentane system at 100°F.l,2 However, Guter and co-workers have studied the phase behavior of the methane-ethane-ethylene system at relatively low temperatures. Information concerning the phase behavior of ternary systems is of value in predicting the behavior of the components in multicomponent systems, since the influence of pressure, temperature, and concentration may be individually ascertained. In the light of the importance of such information, the study of this ternary system was extended to higher temperatures in order to increase the field of temperature in which the data could be applied. Since all states encountered in this investigation are above the critical temperature of methane, the details of its phase behavior are not of direct significance. The properties of propane in the heterogeneous region were taken from a correlation3 based upon recently published data. The corresponding information for n-pentane was taken from experimentally measured vapor pressures and volumetric data.4 The rnethane-propane system has been studied throughout the two-phase region at temperatures above 70°F.,5 while the phase behavior of the propane-n-pentane system has been established for temperatures above 160°F.6 The volumetric and phase behavior of the methane-72-pentane system has been studied in detai1.7,8 The experimental measurements serve to establish with adequate accuracy the phase behavior of the components and of the constituent binary systems for this ternary system. It is believed that, with the exception of the measurements for the methane-propane system, the uncertainties in the earlier data relating to the pure substances and the binary mixtures are probably less than those associated with the values reported here. Method The methods and apparatus employed in this investigation have been described.137 In principle, the method involved the withdrawal of samples of the coexisting gas and liquid phases from a vessel containing a heterogeneous mixture of methane, propane and n-pentane. Provision was made so that

Jan 1, 1943

By W. N. Lacey, R. H. Dourson, B. H. Sage

The compositions of coexisting phases in the methane-propane-n-pentane system were determined at 160° and -2 20°F. throughout the two-phase region, at pressures above 500 lb. per sq. in. The experimental results permitted the calculation of gas-liquid equilibrium constants as well as the establishment of the critical behavior of this ternary system. Although many binary paraffin hydrocarbon systems have been investigated, the experimental work relating to the phase behavior of ternary paraffin hydrocarbon mixtures at elevated pressures is relatively scarce, being limited to a study of the meth-ane-propane-PL-pentane system at 100°F.l,2 However, Guter and co-workers have studied the phase behavior of the methane-ethane-ethylene system at relatively low temperatures. Information concerning the phase behavior of ternary systems is of value in predicting the behavior of the components in multicomponent systems, since the influence of pressure, temperature, and concentration may be individually ascertained. In the light of the importance of such information, the study of this ternary system was extended to higher temperatures in order to increase the field of temperature in which the data could be applied. Since all states encountered in this investigation are above the critical temperature of methane, the details of its phase behavior are not of direct significance. The properties of propane in the heterogeneous region were taken from a correlation3 based upon recently published data. The corresponding information for n-pentane was taken from experimentally measured vapor pressures and volumetric data.4 The rnethane-propane system has been studied throughout the two-phase region at temperatures above 70°F.,5 while the phase behavior of the propane-n-pentane system has been established for temperatures above 160°F.6 The volumetric and phase behavior of the methane-72-pentane system has been studied in detai1.7,8 The experimental measurements serve to establish with adequate accuracy the phase behavior of the components and of the constituent binary systems for this ternary system. It is believed that, with the exception of the measurements for the methane-propane system, the uncertainties in the earlier data relating to the pure substances and the binary mixtures are probably less than those associated with the values reported here. Method The methods and apparatus employed in this investigation have been described.137 In principle, the method involved the withdrawal of samples of the coexisting gas and liquid phases from a vessel containing a heterogeneous mixture of methane, propane and n-pentane. Provision was made so that

Jan 1, 1943

By Edwin C. Barringer

IRON and steel scrap has again become page one news, as it was during the war. To many this is anomalous because the common concept is that the theaters of war are literally paved with scrap as the by-product of war damage and abandoned materiel. To an extent this is true, the bottleneck being the ferreting out and transportation of this scrap. While you as consumers of the electric-furnace grades of scrap-the premium grades-are concerned primarily in only one segment of the scrap market, I believe you ill be interested in a general discussion of the market with subsequent funneling down to your specialty.

Jan 1, 1947

By H. R. Deeth, C. J. Koenig

About ten years ago nepheline syenite was introduced to the ceramic industry and the material has now found application in the various branches of the industry, namely, as a vitrifying agent in white-wares and as a source of alumina and alkalies in glasses, glazes, and porcelain enamels. Spencel described the early mining and processing developments regarding this material. Since the time of his article many research papers have appeared relating to the usage of nepheline syenite but little has been published relative to subsequent mining and processing methods. A complete indexed review of the literature was issued recently by Ohio State University.2 Since "Lakefield" nepheline syenite from Blue Mountain, Ontario (Fig I); is the only commercial ceramic-grade nepheline syenite now being marketed on this continent, discussion is limited to this operation carried on by American Nepheline Limited, Lakefield, Ont., and its subsidiary in the United States, American Nepheline Cory. at Rochester, N. Y. The Deposit Blue Mountain is a long ridge rising to an elevation of about 350 ft at its highest point above the surrounding country and extending for about six miles in a northeasterly direction across Methuen township, Peterborough County. The rock of the Blue Mountain central alkaline intrusive is fine grained, light colored and of even granitic texture. The solidified mass consists predominately of the minerals albite, nepheline and microcline in order of abundance. The average mineralogical composition for the deposit obtained by a study of 112 samples taken regularly over the whole formation is as follows:3 Volumetric Mineral Per Cent Albite.................... 54 Microcline................ 20 Nepheline................ 22 Muscovite................ 2 Mafics.................... 2 (Biotite, hastingsite, magnetite) Total................... loo The mineral nepheline (or nephelite) belongs to the feldspathoid group but is lower in silica content than are the feldspars. It is a silicate of soda, potash, and alumina (NaKAl2O32SiO2). Its presence with albite (Na2oA12O3 6SiO2) and microcline (K2O A12O3 6SiO2) gives the Blue Mountain deposit an alkali content of 15 pct and an alumina content of approximately 24 pct. While this huge alkaline mass is somewhat variable mineralogically, it has a uniform chemical composition. When the iron, mostly in the form of magnetite, is removed during processing, a remarkably uniform finished product is obtained. Geological surveying has disclosed many million tons of nepheline syenite in the Blue Mountain deposit. Diamond drilling in the area where mining is now being carried out indicates a block of about one million tons.

Jan 1, 1949

For the first time in its history the Institute will hold a meeting in the State of Arizona. A few years ago Arizona stood third in the copper-producing districts of the United States. Since that time, with the development of porphyry mines, the output has gone up with great rapidity until it not only is the leading district, but its output at the present tune is at the rate of nearly double the Montana output; which now stands second in the list. In connection with this development, most interesting departures have been made in methods of mining, concentration and smelting. Principles of mining and metallurgy of the greatest interest will be covered by papers which will appear in the Bulletin and be presented at Technical Sessions, while ample opportunity 'will ,be- afforded for those who go to the meeting to see all the points of interest to them. In addition, members will be well rewarded by the marvelous natural features to be seen on the trip, including the petrified forests, the cliff dwellings on the Apache Trail and the Grand Canyon of Arizona. It is planned to start the special train from New York, but members and guests may join the special at other points en route as indicated by the following schedule: ITINERARY Thursday; September 14th, Lv New York Grand Central Terminal 5.30 p.m. Dinner in dining car, a la carte

Jan 9, 1916

By R. E. Hurst, D. E. Ramsey, J. M. Moore

The "frac" method of well stimulation has been applied successfully to all producing formations in the Permian Basin area. During the five years since its development, many changes and improvements have been made in treating materials. procedures, and equipie11t. A number of fluid carrying agents, having different physica1 and chemical properties, have been developed to meet variorus well requirements. The current trend is toward larger gallonage treatments, employing higher injection rates. The use of "down-the-casing" techniques has greatly reduced high surface working pressures, attributable to friction losses resulting from injection throrugh tubing. Petrographic studies of various Permian Basin formations, coordinated with laboratory and well log data, have been found a valuable guide in planning frac treat111o1t.s. A knowledge of the extent (and orientation of naturally occurring fractures and planes of weakness in the formation, aid in predicting the ultimate drainage pattern resulting from the frac treatment. INTRODUCTION The South Permian Basin covers an area in Wcst Texas and New Mexico about onc-half the size of the state of Texas, This vast region has been called the "Permian Basin" for so long that the term will he used here. It includes an area south of the Matador Arch. approximately 250 miles wide and 300 miles long. Structural features of importance within the basin are the Northwest Shelf, Eastern Platform, Midland Basin, Central Basin Platform, and Delaware Basin. The principal producing formations include sand, limestone and dolo-mite, with lesser amounts of shale, anhydrite. chert. and various silicates. All of the producing formations in the Permian Basin have responded to some type of frac treatment. Essentially, a frac treatment may be defined as the injection, into a formation. of a fluid carrying agent containing a particulated solid (usually sand), for the purpose of increasing production. The application of this method of well stimulation to many differing Permian Basin reservoirs has necessitated numerous changes and improvements in carrying agents, solids, service equipment. well equipment. and treating techniques. CARRYING AGENTS A number of different types of fluid carrying agents have been developed since the introduction of the frac method of well stimulation. These agents have different physical and chemical properties, and in many cases the extent of production increase derived from the frac treatment depends on the choice of fluid carrier. Unfortunately, due to many different systems of nomenclature used in the oil field, these differences are not always recognized by the oil Operator. In general, carving agents may he divided into the following broad classi-

Jan 1, 1956

By John Garcia

IN some districts of the bituminous coal field the problem of construct-ing bulkheads to seal off water under pressure is becoming increasingly important. Recently this matter has been brought very much to the front by the loss of a large. Illinois mine due to failure of a bulkhead that separated it from several old, flooded mines. As this great misfortune has provoked much inquiry about proper bulkhead design, it is felt that a description of the successful and extensive water-sealing practice at three mines that have different natural conditions will be of considerable interest to those connected with properties having a present or future water problem and to engineers that may have to design safe bulkheads of economical construction. These three mines are the Saxton acid Dresser, near Terre Haute, Ind., and the Hegeler, near Danville, 111. All three have water conditions that make it necessary to regularly seal off till worked-out sections of the mine, and there are considerably over a hundred bulkheads in each. As far as the writers know, these three mines are the only ones in the bitu-minous coal fields of the United States with anything like so large a number of water seals and experience, although a number of other mines are known to have a few bulkheads. More detail will he included herein on the Saxton mine than on the others, as the writers are more familiar with it.

Jan 1, 1937

By Augustus Locke

The paper has two parts: the field argument and the microscopic argument. The field argument indicates that either the deep chalcocite has replacea sulfide of extraordinarily easy replaceability or it is hypogene. The microscopic argumentindicates that this sulfide, if it existed, must have been hypogene bornite; that this bornite must so excel known bornite in replaceability as to constitute a new variety; that the existence of this new variety is wholly unsupported by evidence; and that the deep Butte chalcocite is therefore hypogene. IN 1900, when the public first heard of "secondary enrichment" the Butte chalcocite seemed clearly supergene. Mining, through successive regions of leached capping, bonanza sulfide, and sulfide less rich, had paused at lean bottom levels which, though chalcocite-bearing, suggested the waning of copper. The deepest chalcocite, at 1500 ft., was yet too shallow to disturb the supergene hypothesis. But, with deeper mining, lean levels yielded to fat ones. Here and there they showed, within the same vein, an inverted distribution, chalcopyrite above and chalcocite below. To the miners' astonishment, they carried chalcocite, unaffected by cross faults, on an independent course to the depth of 2500 ft. The pattern of ore distribution, hitherto revealed only in fragments, was now appearing in perspective, and, in the depth of the chalcocite, was beginning to make Butte differ from all districts where the chalcocite is indubitably supergene. The idea of hypogene origin at length came into favor; by 1913, when Sales1 advocated this origin, the argument had become a powerful one. This argument rested on field evidence; but, already, there was beginning to emerge microscopic evidence not included in this arugment. Especially pertinent was the proof that (1) The deep chalcocite lies in-mixed with bornite, often microscopic; (2) the deep chalcocite often replaces bornite; and (3) replacement of bornite by chalcocite is accom-

Jan 3, 1924

By Brian W. Mackenzie

In this age of advancing technology, mining companies are confronted with increasing competitive forces. The depletion of high-grade deposits and the development of substitute materials are intensifying market competition. The accelerating activity of petroleum companies in mineral exploration is increasing competition for deposits. At the same time, the trend in government policy is towards a reduction in traditional mineral-industry incentives. To succeed, the mining company must respond to these changing economic conditions by developing a decision-making framework that can effectively contend with the new opportunities and constraints. What are the elements of such a decision-making framework?

Jan 1, 1970

By S. M. Parmley

Experience has shown that there are some factors connected with the drying of fine washed coal that are not present in drying of slack coal as normally practiced at cement kilns or pulverized coal plants. It is the purpose of this paper to show some of these variations as they have been encountered under actual operation. The Champion No. 1 cleaning plant of the Pittsburgh Coal Co. uses the wet system of cleaning coal. The plant is equipped to produce commercial sizes or mixtures, the primary sizes being plus 6 in. and 4 by 6 in., which are hand-picked. Minus 4-in. sizes are all cleaned by the wet process. To produce a commercial product as free of moisture as possible, the washed coal is first passed over sizing and dewatering screens, then each size except the — ?-in. coal is conveyed to loading booms by slow-moving draining conveyors. As the +?-in. sizes are not heat-dried, no data will be given, as it is the purpose of this paper to describe the heat drying of — ?-in. coal as practiced at the Champion No. 1 plant of the Pittsburgh Coal Company. To fully appreciate the conditions, it must be remembered that the — ?-in. product is now shipped at a lower moisture content than when received from the mine. The incoming coal in the — ?-in. size will average 5 per cent. moisture and the shipped product 3 per cent. moisture. This is a case where a wet process gives a reduction of both ash and moisture in the fine sizes. The shipped product, therefore, is more uniform in all characteristics, and uniformity of product is the most important single factor in coal preparation. The 0 by ?-in. coal is first dewatered on slow-moving continuous bucket dewatering elevators, running at the rate of 40 ft. per minute, with 48-in. perforated buckets with ¼ by 1½-in. slots, spaced ? by 2?-in. centers staggered. The moisture in the coal discharged from the elevators runs 20 to 28 per cent., depending on the fineness of the product. The discharge from the dewatering elevator is further drained on a drag-type conveyor equipped with ½-mm. wedge wire screen. The conveyor discharges coal with an 18 to 25 per cent. moisture to three centrifugal dryers of the Carpenter type. The Carpenter dryers

Jan 1, 1931

By C. Richard Tinsley

Like most minerals, coal is inherently a demand-limited commodity. The very sedimentary nature of its occurrence implies greater availability potential than demand. But this situation is overridden by economics among fuels, between coals, and within coal blends. Such considerations make coal forecasting a very hazardous profession indeed. THERMAL COAL If one thought that the lead times involved with a mining project were very long, one has obviously not been exposed to the planning process in the electric generation business - a process seriously confounded by shifts in load growth, environmental pressures, capital intensity, security of fuel sourcing, inter-fuel economics, and so on. But as a general rule, the near-term forecasts for thermal coal can reliably be based on a bottom-up, plant-by-plant analysis. Cement plant conversions can also be reasonably estimated next in order of reliability, although they have a much wider spectrum of coal qualities and fuel sources to choose from with a notably higher tolerance for sulfur and ash. Finally, industrial demand can be assembled from the estimates for conversions by pulp/paper plants, chemical plants, etc. The industrial sector is harder to estimate, since it may involve small boilers or dual-fired units. Assessing demand in the Pacific Rim is relatively a straightforward process in the near term because the major importing countries are all located on the Asian continent with either negligible or very minor (yet stable) indigenous coal production, (itself often operated on a subsidized basis). Furthermore, all imports are seaborne. These major importers are Japan, Korea, Taiwan, and Hong Kong with Thailand, Singapore, and Malaysia up-and-coming consumers. The suppliers to this market all have substantial reserves to back up decades of exports to these countries. Australia, the US, Canada, South Africa, China, and the USSR dominate the supply side. The second oil-shock of 1979/1980 has convinced the importers that reliance on oil can be expensive and eminently interruptible. Thus, they are determined to diversify away from oil' to nuclear and coal for generating electricity and for coal for other purposes where possible. This trend is seen to continue even in the face of the oil glut worldwide and oil-price reductions in early 1982. But the importers are also convinced that reliance on one coal source and, in particular, one infrastructure route for the coal chain from mine to consumer can be equally expensive and interruptible. Strikes in the US and Australia; excessive demurrage at certain ports; relegation of coal to a lower priority on multiple-use railroads in the USSR and China; and concern over escalation on high-infrastructure or high-freight coal chains are among the risks worrying the importers. As a consequence, Pacific Rim thermal coal purchases are being allocated among supplier nations, between ports, and within each country. An example of Japan's shift away from Australia and toward the US and Canada is shown in the estimates in Table 1. But the confidence of the import estimates deteriorates sharply beyond the plant conversion timetables and construction schedules in the near term. If part of the second generation of coal-fired power plants can handle lower-energy coals, the field of suppliers could widen to accept sizeable tonnages from Alaska, Wyoming, Alberta, or New Zealand resources. These supply sources generally have some infrastructure or freight advantage to compensate for their lower quality and to compete on a delivered energy-unit basis. These also offer diversification in sourcing. And the possibility of coal liquefaction in Japan further widens the sourcing network. A great number of Pacific Rim coal forecasts have been generated, especially for Japanese thermal-coal imports which are expected to grow strongly in the 1980's. Since the Japanese themselves have not yet settled their energy policy, the exact numbers are hard to call. Nevertheless, at 50 million tonnes of imports in 1990, Japan would consume 50-60% of the total Asian thermal coal imports as shown on Tables 2 and 6. The next most important consumers are the "island" nations of Korea, Taiwan, and Hong Kong (see Tables 3-5). All three are embarking on power plant developments usually with captive unloading facilities, capable of accepting more than 100,000-dwt vessels. Korea, with no-indigenous bituminous coal, is not especially enamoured with US coals, which are deemed too heavily loaded by freight and infrastructure costs -- up to 70% of the delivered price. Thermal coal contracts are presently split to Australia (70%) and to Canada (30%). Korea Electric Power Co. is already considering second-generation boilers capable of burning lower-quality coals than the present standard. Korea does burn domestic anthracite.

Jan 1, 1982

By G. W. LAAiIBOURNE

FEW mines possess a history of more fascinating interest than the Ontario at Park City, Utah. The famous Bonanza's production record of over $50,000,000; the great extent of its workings; the remarkable character of its mineralization; the fact that recent discoveries have shattered preconceived theories of the geology of the camp practically assuring the half-century old property a future as active and as prosperous as the past make the Ontario one of the unique mines of the world. A mere accounting of the wealth created by this historic property not only exemplifies the great profits

Jan 1, 1925

By R. R. Hartman, W. B. Agocs

IN the course of a return flight from Olympia, Wash., to Laramie, Wyo., an airborne magnetometer profile was recorded continuously. The level of flight was controlled at barometric levels along segments of the flight. Barometric altitude was changed from 3000 ft to a maximum of 12,000 ft above mean sea level to take care of topographic variations. Terrain clearance varied from 800 to 7300 ft. Horizontal positions were obtained by recording and tying to cities, towns, airports, river crossings, and other landmarks in the course of the flight. Figs. 1-6 show the course of the flight and the general geologic and tectonic features traversed. The flight line begins south of Olympia, Wash., and proceeds south across the Puget-Willemette depression to the Columbia River. Thence it proceeds eastward along the Washington-Oregon border across the Cascade Mts. and lava flows and the Umatilla basin to Pendleton, Ore. From Pendleton it traverses the Blue Mts. uplift of Oregon in a southeasterly direction, and then to the Boise basin of southwestern Idaho. The flight line swings in an easterly direction as it passes over the Snake River downwarp to the south of the Idaho batholith. It then passes over the northern portion of the Great Basin and the heavily overthrust area at the intersection of the Utah, Idaho, and Wyoming borders. The flight then assumes an easterly course to cross the series of basins and uplifts of southern Wyoming and terminates near the western flank of the Laramie uplift. It should be clearly understood that all statements in this article pertaining to the magnetics were interpreted on the assumption of elongate anomalies transverse to a single profile. Hence any theories or ideas advanced here are in line with future paths of research rather than trying to prove or disprove existing data. Magnetic Interpretation: Depth determinations were made by the slope method of Peters: which is stated as follows: "Draw a line in the maximum slope (at the point of inflection); draw a line whose slope is one-half this maximum slope; draw two lines parallel to this line tangent to the anomaly curve. The horizontal distance between the points of tangency is approximately equal to 1.6 times the depth [or the distance times 0.6251." Certain assumptions must be made for determinations of the causes of the magnetic anomalies:' 1) The anomaly is caused by a susceptibility change rather than basement relief. 2) Polarization of the basement rocks is in the same direction as the earth's inducing field. 3) The disturbing magnetic mass has a great horizontal length in comparison to its width and its sides are vertical and of great vertical extent. 4) The anomaly is unique and not affected by the anomalies from nearby sources.

Jan 1, 1957

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