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By Roy R. Weil, John A. Dziubek

This paper discusses the use of computer modeling, data manipulation, and mapping of three multi-seam coal properties in the Appalachian coal basin. Each case history represents a slightly different application of computer usage for estimation of reserves and planning surface mine sequencing. This practical use of computers demonstrates the suitability of data processing for normal evaluation of coal properties.

Jan 1, 1983

By AIME AIME

EVEN though most of the program of the joint meeting at Easton, Pa., on Oct. 30 to Nov. 1. was devoted to the interests of combustion engineers rather than to coal-mining engineers, nevertheless the A.I.M.E. Coal Division was well represented, with 83, or close to one third of those in attendance giving this as their affiliation. The fuels division of the American Society of Mechanical Engineers had 108 representatives, and an equal number reported no society affiliation. Added to the men's total registration was that of some twenty ladies so the total attendance was in the neighborhood of 325, exceeding that of the last two joint meetings, at Birmingham and Columbus, and equaling the 1938 crowd at Chicago.

Jan 1, 1941

By L. A. Panek, F. D. Wang, M. C. Sun

A method of stability analysis of underground opening by the limiting equilibrium approach is presented. The Coulomb shear failure criterion is employed to find possible fracture surfaces and to evaluate the shear strengths along them. The normal stresses required for the calculation of shear strength, and the shear stresses for the calculation of total shear force along the fracture surfaces, are obtained by the finite-element method of plane-strain analysis. The factor of safety against Coulomb shear failure is calculated as the ratio of the shear strength to the shear force along a fracture surface, similar to the practice in slope stability analysis. Four shapes of openings are analyzed, with three ratios of horizontal lithostatic stress and four coefficients of internal friction. The critical fracture surfaces found by this method of analysis are consistent with the arching of roofs and slabbing of ribs commonly observed.

Jan 1, 1972

By J. M. Clark

(Wilkes-Barre Meeting, June, 1911.) For some years past, those interested in the development of the increasingly important mining industry of Canada, have urged the adoption by the Dominion Parliament of a federal mining-law, which would have the force and stability of statutory enactment. At present, placer-mining in the Yukon Territory, is governed by the Yukon Placer Mining Act. All other mining under federal jurisdiction is governed by 'Orders in Council and Ministerial Regulations. In the earlier stages of development, it is perhaps a matter of necessity that these important matters should be so dealt with; but it is now felt that the time has come when mining-rights in the extensive regions under federal control should be put on a permanent basis, -and that any changes required from time to time should be made only after full and open discussion in Parliament. A short sketch will suffice to indicate how vast and varied the interests affected really are. When the Dominion of Canada was constituted by the Imperial Statute known as the British North America Act of 1867 (which came into force by proclamation on July 1 of that year), it comprised only the present Provinces of Ontario, Quebec, Nova Scotia, and New Brunswick; but provision was made for the inclusion of Newfoundland, Prince Edward Island, British Columbia, Rupert's Land, and the North West Territories. Subsequently Rupert's Land and the North West Territories were acquired, the 'Crown Colonies of British Columbia and * SECRETARY'S NOTE.-Mr. Clark, an eminent Canadian lawyer, and joint author of the treatise on "The Law of Mines in Canada," has been requested by the Do¬minion Government to prepare a Federal mining-law, and presents this paper, by invitation of the Council, in order to obtain, if possible, useful suggestions from members of the Institute.-R. W. R.

Apr 1, 1911

By H. C., Simpson

MANY metals by virtue of their place of occurrence as ore, and their uses are travelers! Iron and steel, for instance, is one of the greatest of travelers in the form of ships and the romance of iron in this respect is only just beginning to be superseded by the stories which can be told of the travels of aluminum and its alloys, used in the building of airplanes. Tin is a traveler from the Straits Settlements to this country and Europe, for use in the canning industry; afterward traveling all over the civilized world as a part of the container for preserved foods. Silver is somewhat of an aristocrat, when its uses are measured against those of the baser metals. From earliest times it has been used for adornment (first perhaps o4 the person and later for the embellishment of weapons and' buildings), for the making of fine ar¬ticles used in the household, and as money. While its uses have been widened by the discoveries in chemistry, electricity and other sciences, its early uses are still much in evidence in our modern life.

Jan 1, 1928

By Donald J. Worth

INTRODUCTION Minera Real de Angeles makes a very interesting case study in more ways than one. To begin with, it represents the first time a bulk silver deposit has been put into production in Mexico. Second, the feasibility and financing stage spanned a period when the silver price ranged from $4 to $40 per ounce. Third, there was a major devaluation of the peso and a financial crisis in Mexico at completion of the project. Fourth, the composition of the partnership (a major Canadian mining company, a major Mexican mining company and the host government's own mining entity) is worthy of note. This paper gives considerable background on the project and how it came to fruition. The political risk aspects and how the major provider of funds perceived Mexican risk at the time of decision to participate and afterwards are highlighted. LOCATION AND HISTORY The Real de Angeles deposit is located at an elevation of 2300 meters in Central Mexico in the State of Zacatecas (Figure 1). The closest village is Noria de Angeles, three kilometers to the north. The closest cities are Aguascalientes, Zacatecas and San Luis Potosi. The first-mentioned is one hour to the southwest by automobile over good roads. Exploitation of the vein outcrops probably began towards the end of the sixteenth century by the Spanish. Evidence of past mining activity is shown by numerous shafts, manways, dumps and ruins. Also, there were remnants of two rudimentary concentrating mills now obliterated by pit development and in the nearby town of Noria de Angeles the ruins of a small smelter still exist. Compania Minera Gamma, an affiliate of a major international mining company, investigated Real de Angeles from 1969 to 1971. Its evaluation program included 20 drill holes and comprehensive geological engineering and metallurgical studies. The results were not encouraging and the option on the property was dropped. In late August 1973 geologists representing Placer Mexicana which was later renamed Explomin were advised of the availability of the property and liked the prospects sufficiently to make an option payment soon due and to agree to outright purchase by year-end. A series of 34 holes were drilled by Explomin and a preliminary study indicated that the prospect had mine-making potential if the silver price was right. [ ] DESCRIPTION OF THE PROJECT Real de Angeles is best described as a large, low grade open pit silver mine because at today's prices approximately 70% of the realizable revenue is derived from that metal. One must also keep in mind that the operation produces two concentrates - a lead concentrate with high silver content and

Jan 1, 1985

By AIME AIME

BUSINESS forecasting may be an inexact science, if it is a science at all, but in the opinion of the statisticians of the American Telephone & Telegraph Co. it is a valuable aid to the making of future business plans, whether it be used by a telephone system, a manufacturer whose distribution is country-wide or, one whose trade is confined to certain sections. Whatever the defects of business forecasting may be; the American Telephone & Telegraph Co: has employed it since 1921, not only for charting the probable; course of telephone traffic over long-distance lines, but' to determine the needs for new plant and equipment: caused by shifting tides in business or increases in population or general industrial expansion.

Jan 1, 1929

By J. B. STEWART

T HE position of each hole of any series of holes was carefully located by the surveyor, plotted in plan and elevation, and numbers assigned to them. The second series was staggered halfway between the first and so on for each succeeding series. Two and a, half to three months was frequently required to grout a series of holes calculated to insure safety for sinking a distance of 10 meters or say 33 ft. Naturally the initial operation called for drilling and grouting two series of holes but thereafter each sinking campaign required only one series of holes as shown in Fig. 8. The pump handling about 75 gal. per minute corresponds to 46 tons of grout or 6 tons cement delivered as a fair over-all average for the 24 hours. Thus 600 to 800 tons of cement was used for a single section of 33 ft. depth of shaft. One campaign used nearly 1100 tons of cement. Some holes were effectually sealed with as low as 30 tons, while many required 60, and some 80 to 90 tons.

Jan 1, 1926

By H. C. H. Darley

The principal causes of unstable boreholes* have been known for many years. For example, in a paper published in 1938, Halbouty and Kaldenbachl listed nearly all the classes of troublesome shales that we know today. Much progress has been made since then, but we still have difficulty in identifying the cause of hole problems and consequently in selecting the right technique for combatting them. This subject was discussed at length by Kelly2 in a recent paper and much valuable information was provided. In the Shell Laboratory it was felt that there was a need for a better understanding of the basic mechanisms underlying the various forms of hole instability, and accordingly, a study was undertaken. This entailed reviewing the physics and chemistry of shales, developing tests for characterizing shales, and constructing a model to study borehole stability. Full simulation of underground conditions was not attempted; for example, we used reconstituted shale specimens, and often simple solutions or suspensions rather than practical drilling muds. Such procedures are necessary in order to establish mechanisms, but caution must be exercised in applying the results to the more complex conditions in the field. Part I — Compaction Swelling and Dispersion of Shales Compaction of Sediments Shales are formed by the compaction of sediments. Water is expressed as sediments are buried by subsequent layers, and the degree of compaction is proportional to the depth of burial, provided the water is able to escape easily to permeable formations. The younger sediments, when recovered at the surface, soften and disperse when mixed with water; the older shales have undergone diagenesis (alteration of the clay minerals, secondary cementation, etc.), and remain hard and unaffected by water. In this paper we shall apply the term "shale", as the drilling engineer does, to everything from clays, which are highly reactive to water, to completely lithified materials such as claystones and slates, which are completely inert. However, because these materials behave quite differently when encountered in the drilling well, it is desirable to develop a simple means of characterizing them. The feature that distinguishes the various shales is their dispersibility in water —soft clays disperse readily, harder shales disperse slowly when agitated, the lithified materials will not disperse at all unless milled. In the dispersibility test used in our study, a weighed amount of dry shale particles in the 12-to-100-mesh-size range was placed in a tube filled with distilled water and allowed to soak for 16 hours. The

Jan 1, 1970

By Thomas H. Leggett

The conditions surrounding this mine are, perhaps, not sufficiently rare or significant to warrant special attention. A certain interest, however, attaches to the locality through the recent discovery of fossil cycads made there by Mr. Charles M. Rolker, of New York, who has repeatedly visited this district, fixing the geological horizon

Jan 1, 1889

By HARRISON W. CRAVER

LIBRARIES are universally recognized as essential to modern civilization. In a world that gets most of its learning through the printed word, storehouses of print are a vital necessity. In this regard engineering differs in no way from the other learned professions, but until recent times the library needs of engineers have received rather scant attention. When the engineering profession was more of an art and less of a science than it is today, when each problem was solved more through the results of experience than by applying scientific principles, literature was less helpful. The engineer of today, however, is aware that his activities rest upon a scientific foundation and consequently comprehensive books dealing with more limited fields are now being published. Another difficulty for the operating engineer in the past was that the published works on engineering were written chiefly for use as college texts. A third obstacle to the development of engineering libraries has been the lack of librarians with experience in engineering.

Jan 1, 1938

By R. J. Charles

Previous study of simple impact systems indicated that energy required for fracture and size reduction of brittle materials is greatly dependent on the type of loading that is employed. In this regard it was postulated that fracture and size reduction of a brittle specimen might be accomplished by a high velocity impact at an energy level at which a low velocity impact would leave the specimen relatively undamaged. The finite time required to propagate energy away from the point of loading of an impacted object to other parts of the object and to its supports may permit a concentration of energy at the point of impact if the rate of loading is high. Localizing of energy at the point of impact could quickly initiate fractures that would propagate through the impacted material along with the traveling stress waves. As the cracks form, the initially absorbed strain energy would be released and portions of it travel ahead of the crack tips as stress waves. These secondary stress waves, combined with the initial stress waves derived from the impact, would produce high localized strain conditions in front of the fracture zone. The fracture zone would propagate and the specimen shatter. High rates of loading are brought about by short impact times, in turn obtained by employing high velocity projectiles that are of small mass compared to the impacted object.

Oct 1, 1956

By GEORGE L. CHRISTIAN

T HE Tonopah Extension assay office is a two- story, concrete structure on a solid foundation of andesite, situated about 100 yd. from the company's mill, so that it will not be affected by the stamps or the tube-mills; also it will not be affected by under- ground blasting. On the second floor are the mine superintendent's office and drafting and blueprint rooms. On the ground floor are the assayer's office,' mixing room, furnace room, crusher room, chemical laboratory, parting room, store room, and change and shower room for the mine superintendent, assayers, and engineers. The crusher room is outside of the main building, and has four concrete walls, thus eliminating the jar of the crusher; it is so situated that the least possible amount of dust spreads through the main building. An 8 by 10-in. jaw crusher, which crushes to ¼ in., was made by a local foundry. Attached to the top is a small galvanized-iron hopper covered with a ¼ in. screen, on to which the sample is dumped. The fines-pass through the screen into the hopper, while the oversize is dumped into the crusher. The crushed sample and fines from the screen drop down to a set .of splits suspended from an iron rod below the crusher jaws. The small sample is caught below in a small pulp pan. The rejects drop from the splits through a 2-in. pipe on to a bucket conveyor, which dumps into a galvanized-iron hopper in an upper corner of the room. The rejects drop through a 2-in. pipe to a reject bin outside the build- ing. This bin is constructed high enough for a truck to be loaded from it by means of a chute door on the side.

Jan 1, 1921

By V.F. Marsters

Seepages of oil in Ecuador have been known for many years. The locality first to receive attention, and still worked in a modest way, lies on the north shore of the Santa Elena peninsula, between La Puntilla and Salinas. Operations mere first conducted largely by local cdpital. Later, foreign companies acquired large blocks of land, where they have done considerable drilling. For details concerning present drilling activities in Ecuador, we are indebted to Leon Price, an Ame~ican resident engineer of Ecuador. The information solicited came to the author through the office of the American Consulatell with permission to use it. The coastal plain bordering the Province of Tumbes, Peru, continues to the northeast, but narrow on passing the Zarumilla River. From this point northward it widens toward Santa Rosa. In fact, the pampas, as shown on the official Wolf map, correspond fairly well to the areal extent of tbe coastal plain as far as Guayaquil. This is shown in a general way on the accompanying map. The author understands that the Guayaquil enlbayment is bordered on all sides by the coastal plain, as recognized at Tumbes and farther southwest, and that it can be followed without a break as far north as Palmar. This view is supported by the mapped area regarded by Mr. Price as favorable or possible oil territory. Moreover the islands in the Gulf of Guayaquil are the same geologically as the coastal edge, being composed of Tertiary sediments. The author understands also that Tertiary formations occur north of Palmar. According to a report by Mr. Cardon, of Guayaquil, Tertiary sediments are exposed in the region of San Francisco and extend to and beyond Pta. Calera. There is also reason to believe that at least the lower part of the valley of the Santiago River is occupied by Tertiary sediments, ~~hich probably border the const line and extend into the River Mini l)nsin, and into Colombia. On the south coast there are many seepages, most of them near the inner edge of the coastal plain, between Zarumilla and Santa Rosa and also between Santa Rosa and Machala. I11 the latter region are

Jan 1, 1923

By V. F. Marsters

Seepages of oil in Ecuador have been known for many years. The locality first to receive attention, and still worked in a modest way, lies on the north shore of the Santa Elena peninsula, between La Puntilla and Salinas. Operations mere first conducted largely by local cdpital. Later, foreign companies acquired large blocks of land, where they have done considerable drilling. For details concerning present drilling activities in Ecuador, we are indebted to Leon Price, an Ame~ican resident engineer of Ecuador. The information solicited came to the author through the office of the American Consulatell with permission to use it. The coastal plain bordering the Province of Tumbes, Peru, continues to the northeast, but narrow on passing the Zarumilla River. From this point northward it widens toward Santa Rosa. In fact, the pampas, as shown on the official Wolf map, correspond fairly well to the areal extent of tbe coastal plain as far as Guayaquil. This is shown in a general way on the accompanying map. The author understands that the Guayaquil enlbayment is bordered on all sides by the coastal plain, as recognized at Tumbes and farther southwest, and that it can be followed without a break as far north as Palmar. This view is supported by the mapped area regarded by Mr. Price as favorable or possible oil territory. Moreover the islands in the Gulf of Guayaquil are the same geologically as the coastal edge, being composed of Tertiary sediments. The author understands also that Tertiary formations occur north of Palmar. According to a report by Mr. Cardon, of Guayaquil, Tertiary sediments are exposed in the region of San Francisco and extend to and beyond Pta. Calera. There is also reason to believe that at least the lower part of the valley of the Santiago River is occupied by Tertiary sediments, ~~hich probably border the const line and extend into the River Mini l)nsin, and into Colombia. On the south coast there are many seepages, most of them near the inner edge of the coastal plain, between Zarumilla and Santa Rosa and also between Santa Rosa and Machala. I11 the latter region are

Jan 1, 1923

By C. C. Miller, A. B. Dyes

The cost of finding and developing new reserves is continually rising. We must meet these rising costs with more economical operations. This can he accomplished if we revise our ideas of proper well spacing and well allowable to consider the concept of optimum well spacing. According to this concept, the optimum spacing is the one which leads to the maximum present worth for a reservoir when ail factors affecting total cost and total revenue are considered and when the wells are produced in the most eficient manner. Application of this principle efficiently utilizes available well potential and properly considers the recovery eficiency in addition to fixing the spacing on the basis of the amount and value of the oil to he recovered. This Study presents an analysis of one producing zone containing low gravity crude to illustrate the effect of these factors on the present worth and on the optimum economic spacing under two production drives—-evolved gas and water drive. The maximum present worth occurs when the optimum number of wells for open-flow operation is employed. Frequently, this optimum development cal1s for very wide spacing and the ideal field rates are not unreasonable. Under other circumstance. where proration is necessary, an optimum combination of well spacing and well allowable exists which permits production at relatively high rates. The optimum well density in a field depends on the recovery efficiency and the valule of the oil. In solution gas-driven reservoirs this optimum spacing for operation at high producing rates can vary from extremely wide spacing to handle viscous low gravity oil in thin formations to relatively close spacing in thick sands where good recoveries are expected. Because of the better recovery from water-driven fields, the optimum spacing in these fields is closer than in solution gas-driven fields. Also, the water encroachment pattern is dependent upon the well spacing, and an adequate numher of wells is needed to assure a good sweep eficiency. The economic optimum well density in a water-driven field is high enough for this purpose. INTRODUCTION From year to year domestic oil becomes more difficult to find. The fields we do locate are frequently smaller and deeper than older fields and the costs for men, material and equipment are continually rising. To replenish our reserves we must continue to search for and develop new fields, but experience has shown we cannot expect prices to rise in proportion to costs. Consequently, we must meet increasing costs by more economical operations. A vigorous effort is being made within the industry to improve exploration methods, to cope with the problems of deeper drilling, and to obtain a secondary yield from older fields. Many significant contributions have resulted from these efforts. The economic operation of new fields can be further improved by developing these fields on optimum spacing and producing the wells at higher rates. This would avoid the drilling of unnecessary wells and provide additional capital for seeking new oil. While the benefits of these practices are obvious, the problem of defining the optimum development of a field for natural depletion can become very complex. A study of the effect of well spacing and several reservoir variables on economic worth of a specific field is reported here to illustrate the problem and to show the magnitude of the benefits to be realized. This study is necessarily limited to the field conditions selected and is not intended as a general solution of the well spacing problem. It does, however, indicate factors to be considered, the trends to be expected, and the direction in which we should proceed in developing new fields. NO consideration is given to land and legal considerations which might arise. METHOD OF ANALYSIS The optimum method of developing and producing a field is to use the combination of spacing and prora-tion which gives the maximum return. In addition, we do not want to lose recovery. These considerations of maximum return and maximum recovery present no serious conflict. The value of each method of operation is conveniently expressed in terms of its present worth. According to the present worth method of evaluation,' an acceptable annual percentage return is assigned to the operation, and all incomes, capital costs, and expenses are discounted at this rate to the start of the operation. This net value is the present worth. If we apply the same discount rate to several alternate methods of operation, the one yielding the greatest present worth is the best method. If we express net income in terms of price per barrel of oil produced, drilling and equipment costs on a well basis, and expenses as cost per well year, this evalu-

By Hallan Marsh

THE subject of this paper is apt to bring to mind wells ranging from 6000 to over 8000 ft. in depth. However, it is uncommon to pump wells at depths greater than about 5000 ft. Fig. 1 shows the number of wells being pumped at various depths by one company in Southern California. FIG. 1.-NUMBER OF WELLS BEING PUMPED BY ONE COMPANY FROM VARIOUS DEPTHS IN SOUTHERN CALIFORNIA. A few companies have a very few wells pumping at depths greater than this. This paper will deal with wells between 3000 and 5500 ft. in depth. Most California oils at these depths are between 25° and 35 gravity. The subject is so broad that it will be necessary to omit many interesting phases, and to treat others very briefly. Power, power transmission equipment, power efficiency, counterbalancing, sucker rods, pumps and volumetric efficiency will be discussed.

Jan 1, 1928

By C. E. Sims, G. A. Lillieqvist

The following presentation is more a summation of observations made and conclusions drawn over a period of three to four years than a report of experiments made with a definite objective. Tests were made, of course, to verify hypotheses, but the large mass of data was collected incidental to other work. Lack of space forbids the presentation of more than a few of those data. On the other hand, it is unfortunate that some of the most illustrative examples are not available. The work is admittedly incomplete but is presented in the hope that it will stimulate further work along a similar line. The answers to many of the questions left unanswered by this paper will be found only after long and painstaking study, such as is scarcely possible in a commercial laboratory where problems of immediate importance consume most of the time. It is also hoped that this study will in some measure throw light on some of the dark spots of steelmaking, and help to clarify some of the annoyingly vague references to "good practice." Only cast steel was studied and the conclusions apply to cast steel, but it is the authors' opinion that the quality of rolled or forged steel is largely dependent on the quality of the ingot, which is a casting. Although this discussion deals almost entirely with inclusions, it is important that the reader understand that only those natural inclusions which owe their origin to the solubility of certain materials in steel and to the chemical reactions of steelmaking are considered. Accidental inclusions, such as entrapped particles of slag, nozzle, runner, or mold arc outside its province and are not considered. Such accidental inclusions are always dangerous and should be carefully avoided. Relation between Ductility and Nonmetallic Inclusions In September, 1928, an acid electric furnace was put into operation at the Indiana Harbor plant of the American Steel Foundries. Following the usual practice, aluminum additions were made in order to obtain sound castings. Immediately the problem of low ductility arose. Previous to that time, only open-hearth steel was produced, and, aluminum being used rarely in that steel, there had been practically no trouble with low ductility in the lower carbon range.

Jan 1, 1932

By Nathan C. Rockwood

BASIC mineral commodities may be divided into two general classifications in their market or price characteristics. In one class are commodities sold on a world-wide basis, as gold, silver, nickel, asbestos and petroleum, and in the second are those produced and sold locally. Of course, no precise line of demarcation exists between the two; coal, for instance, belongs more or less in both. If there are enough producers of any commodity to prevent control of production by any one person or group, a free market then exists and the price in a buyer's market is determined by the most favored producer-meaning the producer, with the lowest production cost or the lowest cost of transportation, or both, to the particular market, or place of use. With minerals in the first classification, their high intrinsic value far outweighs the transportation cost and a uniform market price is accepted as an essential element in the economy of distribution. But with common minerals of small. intrinsic value and relatively high transportation costs, economists are reluctant to admit that a uniform price may also be an essential element in distribution.

Jan 1, 1940

By Frank J. Tolonen

BENEFICIATION of iron-bearing formations is one of the major problems of research at the Michigan College of Mining arid Technology. Funds for this purpose hate been supplied by the State of Michigan supplemented by contributions of labor and some supplies from the Federal Government during the depression. The iron-mining companies have cooperated in securing samples and have also furnished much valuable information relative to the various formations.

Jan 1, 1937