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By Milton Williams

It is generally recognized that fluid is lost from rotary drilling muds to permeable strata during normal drilling operations;1,2-3 but that this fluid is the filtrate from the mud, rather than the mud itself, has been shown by various workers.1,4,5 The presence of this filtrate in oil-bearing or gas-bearing strata is undesirable and harmful. The decreased permeability of the stratum to oil effected by the presence of water has been pointed out by several investigators,6,7 and since, in the production of the reservoir fluid, the greatest pressure drop occurs immediately adjacent to the borehole, it follows that infiltered water is particularly objectionable in this region. Again, this filtrate tends to make electrical logs less reliable, since oil in the proximity of the borehole is probably flushed out to an appreciable extent by the water.8 Observation of side wall cores may be misleading for the same reason. Drill-stem tests in low-pressure areas may be of doubtful value where no oil is recovered, unless sufficient time is allowed for production of water lost from the mud. The infiltered water may hinder drilling operations by softening shales and causing sloughing; the ['tight hole" occasioned by excessive deposition of filter cake in the hole is a common occurrence. The filter cake remaining on the face of the producing formation may itself sometimes be detrimental to production.9 In view of these implications of the importance of filtration of mud, an investigation was undertaken to determine the factors involved in the infiltration process, and to correlate these in such a manner that the values obtained in routine filter tests employing a conventional filter of the "wall-building tester" type,10 together with data on size of hole, drill pipe, and rate of mud circulation, could be used to estimate water loss and distance of penetration of the filtrate into strata. Quantitative relations of filter-cake permeability, filtrate viscosity, and rate of filtration have been developed for filtration in the simple laboratory filter.4a,11,12,13 It is obvious, however, that the conditions

Jan 1, 1940

By R. H. Swallow, George Hess

Aerial photography was once a crude, uncertain tool. Today it is a precision mapping instrument which saves important time and money for strip mining and other industry. Aerial photography began in the boxkite days of aviation. The Army first used it for rough reconnaissance photographs. Then, in the early Twenties, industry began to use aerial photographs of their plants and facilities for advertising or annual reports. The quality of these pictures was not very good by today's standards, but this work began the development of better cameras, better lenses, better photographic techniques.

Jan 1, 1949

By Norman Yarborough

Much has been written about the energy fuels including their standing with respect to reserves, their delivered Btu costs, their potential in the electrical generating market and their capabilities to meet a burgeoning demand. Yet, when all factors are placed in their proper perspective, the spiraling electrical energy market alone should guarantee each fuel a better than average market for the foreseeable future. In fact, a study made by the U.S. Federal Power Commission on the spare capacity utilities have on hand indicated that 39 of the 181 major utility systems had less than 10% reserves on hand at the end of 1969. Fuel supplies are critically low in some areas, especially in the Southeast, South Central and Midwest areas of the U.S. In other systems equipment shortages resulting from faulty equipment or delays in getting new equipment deliveries causes power failures during peak loads. In addition, lack of labor curtails the erection of some new facilities and prevents many other facilities from operating at capacity.

Jan 1, 1970

By M. Muskat, R. D. Wyckoff

The general problem of the simultaneous movement of water and oil in a connected sand is of considerable practical interest from two points of view. First, there is the situation usually described as "edge-water encroachment." Here the water in the sands contiguous to and flanking the oil sand begins to enter the latter as the oil is removed and the reservoir pressure declines. The physical questions involved concern an understanding of the mechanism of the advance of the water and its control, so as to aid the oil recovery rather than to hinder it. In so far as the entry of the water into the oil sand means at least the partial replacement of the oil from the region of the encroachment by the advancing water, it is quite appropriate to consider this type of situation as one of natural water-flooding. For the present discussion, however, we are primarily interested in the problem of artificial flooding. Here the water is deliberately injected into the oil sand with the intention of displacing the oil and removing it through prearranged output wells. For the practical development of such a procedure rather large areas are included in the flooding program and the injection and output wells are arranged in regular patterns or networks, which are felt to be most favorable for a high oil recovery. Although remarkable success has already been obtained in such flooding programs, especially in the Bradford field of Pennsylvania, essentially by the application of the lessons of practical engineering experience, a more thorough physical analysis of the problem appeared to offer promise of leading to results of some interest and value. Another phase of the problem, which stimulated both the experimental and mathematical analysis, is that it is susceptible in large measure to empirical field tests. It, is in itself but an example and illustration of the general theory of the flow of dead (gas-free) liquids through porous media, in which the authors have been interested for the last several years. From the point of view of its applicability to actual petroleum technology problems, however, water-flooding is a particularly favorable

Jan 1, 1934

By E. P. Pfleider, W. G. Pariseau

Even as the rational selection of excavation equipment requires a matching of machine performance capabilities to rock response characteristics, the functional features of transportation systems must be matched to the characteristics of the materials handled in order to secure optimum, trouble-free operation. In particular, ore passes and chutes must be designed for flow in order to insure controlled draw whenever a chute is opened. The alternative to quantitative design is, of course, the well known ad hoc procedure of freeing plugged ore passes, cleaning up spillage from flooded chutes, etc., after installation of the system. Since the voluminous empirical work sporadically undertaken through the years evidently had not led to reliable design methodology, it seemed worthwhile to attempt a rational and complete description of the movement of material through ore passes. The concepts of de- formable body mechanics applicable to gravity-induced flows of granular media or "soils" were involved. Accordingly, the mathematical theory of soil plasticity was adopted as a working hypothesis, and a two-dimensional laboratory model of an ore pass constructed in order to investigate the appropriateness of the theory. The general experimental strategy consisted of formulating the movement of material in ore passes as a boundary value problem in soil plasticity, determining the required boundary values of stress and velocity experimentally, and then using these data for the initiation of a theoretical solution for stress and velocity throughout the moving mass of material. A comparison between the theoretical and experimental constituted the test of the original hypothesis.

Jan 6, 1968

By L. C. Brown, J. S. Kirkaldy

AS part of a program to investigate the diffusive properties of dilute ternary austenites, we have made a determination of the effects of cobalt on the activity of carbon in y iron. Samples of pure iron and Fe-Co alloys were equilibrated at 1000°C in controlled CO-C02 atmospheres, following the procedure of R. P. smith.' The 0.010-in.-thick samples were analyzed for carbon by microcombustion analysis2 to give a set of isoactivity curves. The latter were converted to activity-coefficient (standard state at infinite dilution) plots by combination with Smith's data' for the activity of carbon in pure iron measured in a CO-C02 mixture. Table I shows the composition of the base alloys used, while Fig. 1 shows the experimental results superimposed on a set of curves generated by the relation In the notation of Wagner,' the interaction parameter is the second coefficient on the right, Eq. [I] adequately correlates the experimental points for those alloys which were prepared from electrolytic iron by arc-melting (2,4, and 7 pct Co). The results for the 10 pct Co alloy (supplied by Crucible Steel Co.) do not correlate with the others. In fact, the experimental points for this alloy correspond to an interaction parameter of It is possible that the interaction parameter is a function of concentration for large cobalt additions, but we are inclined to attribute the discrepancy to the presence of a significant amount of aluminum added to this alloy for deoxidation purposes (Table I). Preliminary measurements for the system Fe-C-A1 have indicated an interaction parameter of Which implies that the effect of aluminum in solution on the carbon activity is sixty times greater than the effect of an equal weight percentage of cobalt. These observations cast some doubt on the precision of the results of Chandhok, Hirth, and Dulis who used this same 10 pct alloy for their experiments, obtaining an interaction parameter of E = 2.2. There is considerable doubt as to the activity of a plane Fe-C system. Using a CH4-Ha mixture, Smith obtains cg = 6.1 for the effect of carbon on the activity of carbon in austenite, rather than the value of 8.9 given in Eq. [I]. The use of CHa-Ha mixtures has recently been questioned by Kaufman, Radcliff, and cohens who state that there is some possibility that other hydrocarbons are formed. Fortunately, the determination of the interaction parameter is not sensitive to the coefficient of Nc. For example, using the CHI-H2 results we obtain a value which is almost the same as that obtained using the CO-CO, results. The authors wish to thank Mr. E. J. Dulis of the Crucible Steel Co. of America for supplying us with samples of the 10 pct Co alloy used in their original work. Financial assistance from the American Iron and Steel Institute is gratefully acknowledged.

Jan 1, 1963

Polluted air and water, despoiled land and excessive noise are the unwelcome results of the population growth and a rising standard of living. The consumption of goods and services, including metal products and minerals, by all people is increasing so rapidly that civilization is in danger of destroying the environment in which it lives. This is true because every human activity affects the environment, whether it is air, water or land. While E. F. Osborn, director, U.S. Bureau of Mines, says . . . "some members of the mineral industry are reluctant to recognize environmental demands" . . . William T. Pecora Under Secretary of the U.S. Department of the Interior.. . says that, "to maintain levels of resource development and environmental quality needed to satisfy our affluence, we must trade off values rather than turn off troublesome operations." What it seems to boil down to is how much control of its operations is the mineral industry willing to accept-internal policing or strict government control? The answer lies in how well the mineral industry maintains a balance between mineral development and environmental quality.

Jan 1, 1971

By C. G. Dunn, J. L. Walter

Secondary recrystallization to the (110) [001] texture in high-purity silicon iron occurs if low-oxygen material is annealed in a nonoxidizing atmosphere. Any departure from these conditions results in a growth of (100) oriented grains. The nature of the matrix and secondary recrystallization structures and textures and the nature of grain boundary interactions during growth show that the low gas-metal interfacial energy of the (110) surfaces provides the driving force for growth of these grains. A type of grain growth, characterized by a driving force which derives from energy differences of {hkl} surfaces at the gas-metal interface, has been treated in recent papers.&apos;-7 Secondary recrystallization to the cube text!:: in high-purity silicon iron provides one example. The present paper also deals with a surface energy driving force but the texture that results by secondary recrystallization is not the cube texture; it is a texture in which the (110) plane is in the plane of rolling and the [001] direction is in the direction of rolling. The phenomenon described in this paper is different from the impurity (dispersed phase)-controlled secondary recrystallization process in which the (110) [001] oriented grains grow under the action of grain boundary driving forces.8-12 It is also different from tertiary recrystallization,2 which also produces the (110) [001] texture in high-purity silicon iron, since the matrix textures and grain sizes are different. Finally, it is unlike any other form of secondary recrystallization reported in the literature. The possibility of obtaining the (110) [001] texture in high-purity silicon iron became clear in a study of the effect of impurity atoms on the energy relationships of (100) and (110) surfaces. In this study Walter and Dunn6 observed the migration of (100)/(110) boundaries, i.e., boundaries between two grains, one of which has a (100) plane and the other a (110) plane, respectively, parallel to the plane of the sheet specimen. At 1200°C the (100)/(110) boundaries advanced into (100) grains in a vacuum anneal, then reversed their direction and migrated into (110) grains in a subsequent anneal in impure argon. Finally, the direction of migration reversed once again with (110) grains growing into (100) grains in a second vacuum anneal. These results were explained in terms of a change in concentration of oxygen atoms at the gas-metal interface during the anneals. Thus, oxygen atoms were added to the surface during the anneals in impure argon to the point where ?100, the specific surface energy of the (100) oriented grains, was lower than ?110, the surface energy of (110) oriented grains. In vacuum, however, the oxygen concentration at the surface was lowered to the point where ?110 < ?100. Concerning the possibility of secondary recrystallization in high-purity silicon iron with a low initial oxygen concentration, the observed effect of adsorbed oxygen atoms has indicated6 that a good vacuum anneal would favor the rapid growth of matrix grains with the (110) plane in the plane of the sheet much more than grains in the (100) orientation. The growth of only (110) oriented grains of course would depend upon y110 being less than ?hkl, where hkl refers to any plane different from (110). The present paper is concerned with the application of the above ideas to secondary recrystallization to the (110) [001] texture in high-purity silicon iron. The matrix and secondary recrystallization textures and structures are defined and discussed. Observations of growth of nuclei for secondary recrystallization and of boundary interactions are included to provide direct information on the surface energy relationships between (110) and other (hkl) surfaces. EXPERIMENTAL PROCEDURE As before, 2,4-6 high-purity iron and silicon were melted and cast in vacuum to provide an alloy containing 3 pct Si with less than 0.005 wt pct impurities. The oxygen content of the ingot was lower than in previous ingots, being approximately 3 ppm (by weight). The carbon content of this ingot may have been slightly higher than was found for previous ingots. The same rolling and annealing schedule used previously2 was followed in this study to obtain samples 0.012 in. (0.3 mm) thick. These samples were electropolished prior to annealing. After rolling and polishing, the oxygen content of the material was approximately 6 ppm; material used in the previous studies contained about twice this amount of oxygen.

Jan 1, 1961

By Lysle E. Shaffer

INCREASING attention has been given in the last decade to the possibilities of mine leasing in the West. The practice as described in this article does not refer to the leasing of entire properties for corporate operation. It is intended to deal rather with the advantages and problems incident to leasing portions of properties to individuals who themselves, individually or in groups, do the actual mining and transportation of the ore. These individuals are sometimes called "leasers" and sometimes called "tributors." The contracts under which they work set up an independent relationship of lessor and leaser, between themselves and the mineowner or operator. This relationship has many advantages to both sides over those created by the ordinary relationship of employer and employe. From the standpoint of the owners there is no liability on independent contractors for industrial injuries, social security taxes, unemployment taxes, or the manifold restrictions of the Federal Labor Relations and Wage Hour Acts and similar state acts where they exist. As the leaser&apos;s income depends on the quantity and quality of ore produced, there is a distinct incentive for maximum production of a good grade of ore. This in turn promotes careful mining of the areas under lease. Ordinarily in mining, labor cost is a high percentage of the total cost of operation. Under a leasing system, even if the leasers be allowed to retain half of the gross values that they produce, and the owner or operator gets half, in the case of marginal ore bodies this is ordinarily more than the lessor would realize if the property were worked by day labor. In some instances mineral deposits under a leasing system may become ore, whereas under a day-labor system they would

Jan 1, 1948

By C. G. Dunn, F. W. Daniels

IN recent publications1-5 the existence and behavior of subgrain boundaries in high-purity metals has been clearly brought to light. Lacombe and Beaujardl by means of special etching methods disclosed in polycrystalline sheets of aluminum the existence of substructures differing in orientation by small amounts (about 1/4"). Boundaries of these structures at relatively high temperatures had the remarkable property&apos; of moving about while the ordinary boundaries remained stationary. Cahn2 also observed substructures in bent and annealed single crystals of aluminum, zinc, magnesium, and rock salt. The position of subboundaries could be explained in terms of a dislocation mechanism of polygonization in which dislocations move into lines at right angles to the bent glide planes thereby relieving elastic stresses in these planes. Guinier and Tennevin8,6 disclosed the further interesting feature that polygonized structures coarsened significantly upon prolonged annealing. Somewhat similar subgrain phenomena have been observed in silicon iron of commercial purity. Although some evidence for the development of macro-mosaic structures in silicon iron already has been reported by one of the authors6,7 under the phenom-enological term "crystal recovery," much better evidence recently has been obtained due to improved etching techniques. In addition, phenomena regarding structural changes have been uncovered. The present investigation is divided into three parts: (1) The phenomenon of Laue spot sharpening on annealing cold-rolled crystals, (2) the phenomena of polygonization and subgrain coarsening The material used in the present investigation was high-grade commercial silicon iron sheet of nominal composition, 3.3 pct Si, 0.004 C, 0.011 P, 0.010 S, 0.04 Mn, 0.01 Al, 0.04 Cu, 0.01 Sn. Large single crystals of this material Were prepared for cold-rolling or bending as scheduled. Cold-rolling of 12 pct was carried out on a laboratory 8-in, diam rolling mill. The bending deformations were performed by pressing the crystals between a solid Fig. 2—lllustrative foue patterns to show Laue spot sharpening. a (Left)—Specimen as cold rolled, b (right)—After 48 hr at 1400°C. round bar and a mating half cylinder, both heavily greased. Individual specimens were cut from the deformed crystals, and the cut edges were deeply etched prior to annealing. Laue photographs were made using 40-kv tungsten radiation. The technique used to disclose the various subboundaries was an electropolish and electroetch in a bath of chrome-acetic acid.&apos; The anodic polishing done at 22 v was immediately followed by etching at a reduced voltage, which was dependent upon the nature of the subboundaries. Phenomenon of Laue Spot Sharpening on Annealing Cold-Rolled Crystals Fig. 1 gives the initial and final orientations of the specimens cold-rolled 12 pct. Each specimen was annealed at a temperature and for a time which caused significant structural changes as evidenced by alterations in Laue patterns. Representative Laue patterns and micrographs showing the essential changes are given in Figs. 2, 3, and 4. The essential points to be derived from these illustrations follow: 1. Annealing at 950°C clearly develops a substructure with the orientation of the cold-rolled specimen. 2. The subboundaries formed obviously separate regions of nearly the same orientation. Some of the subboundaries appear as a sequence of dots similar to those observed in aluminum by Lacombe and Beaujard,&apos; but whether this is due to extremely small differences in orientation is not known at present. 3. The substructure coarsens upon prolonged annealing. 4. Prolonged annealing also causes a decrease in orientation spread according to Laue spot sharpening&apos;

Jan 1, 1952

By J. F. Abel, F. T. Lee

Subsidence is controlled by a complex com¬bination of mining and geologic factors. For example, a compilation of worldwide data shows that, as the percentage of shale in the overlying rock mass decreases and the amount of sandstone increases, the angle of draw (and the area affected by subsidence) decreases. Limestone in the over¬burden appears to cause a more than twofold decrease in the angle of draw compared to a like amount of sandstone. Increased amounts of sandstone were accompanied by a greater surface subsidence relative to the mining height. The total thickness of overburden did not appear to influence the subsidence magnitude above super-critical panels. The greater the thickness extracted, the smaller percentage of that thickness shows up at the surface as subsidence. The greater the percent of the seam extracted, the greater the subsidence reaching the surface. The maximum subsidence above room-and-pillar panels de¬pends on the pillar height and minimum width as well as the other factors listed.

Jan 1, 1984

By Thomas Fraser, David R. Mitchell

THE primary purpose of the loading plant is to transfer the finished product from the preparation machines to the railroad car, truck, or barge in which it is to go to market. Secondary purposes of the loading plant are: to prevent excessive degradation of sizes during loading, to reduce segregation as much as possible, and to prevent excessive quantities of very good or off-grade coal from entering any one car. Nonuniformity of consignments is one of the chief sources of com- plaints by consumers and coal merchants. A properly designed loading plant will do much to reduce complaints and ensure uniformity, not only from shipment to shipment but also in each individual consignment along the length of the car and in cross section. DEGRADATION IN STORAGE, LOADING AND SHIPMENT The object in loading is not only to handle the coal without breakage and segregation, but also to produce a well-trimmed load that will ride to its destination without spillage or breakage en route. The small sizes present in a car of prepared coal as received by the purchaser consist-of: missed small sizes not screened out in the preparation plant, breakage during loading, and breakage caused by handling en route. For domestic sizes of anthracite shipped from the Pennsylvania anthracite field to Atlantic coast cities, the dealers&apos; lass because of breakage in loading and shipment amounts to from 2 to 5 per cent and for anthracite shipped to Middle West cities, the loss is 8 to 9 per cent. This difference is in part because dealers in the Middle West rescreen their coal more thoroughly than is usual in the East. One dealer handling Illinois No. 6 coal shipped from southern Illinois mines to Chicago reports an average size loss of 10 per cent when lump coal is unloaded with a fork. This runs as low as 5 per cent for carefully loaded coal and as high as 15 per cent for carelessly loaded coal.

Jan 1, 1943

By Cyril Wells

THE diffusion of carbon in gamma iron plays an essential role in many metallurgical processes. In carburizing, in graphitizing, in homogenizing, in the formation of pearlite from austenite, and in other processes, migra-tion of carbon in gamma iron occurs.1,2 A full understanding of the rate at which these processes occur obviously requires a knowledge of the rate of diffusion of carbon. In carburizing, for example, the depth of carbon pentration is determined by the carbon concentration in solid solution at the surface, and by the rate of diffusion inward of the carbon. Until reliable data on the rates of diffusion of carbon are available it is unlikely that a full quantitative description of this process will be obtained. In the formation of pearlite from austenite, the segregation of carbon and alpha iron from the austenite obviously requires the diffusion of carbon; the rate at which pearlite nodules grow is evidently controlled at least in part by the rate of diffusion of carbon; it is unlikely that we shall understand the factors that determine the rate of growth unless data on rates of diffusion of carbon, and the variation of these with com-position, grain size, and temperature are available. Accordingly it was decided: (1) to determine, more accurately than hitherto, the diffusion coefficients of carbon in austenite over a wide temperature and a wide concentration range, (2) to study the influence of grain size and impurities on this diffusion coefficient, and (3) to study the effect of manganese and nickel on the rate of diffusion of carbon in the austenite of manganese and nickel steels, respectively; the influence of carbon on the rate of diffusion of manganese and of nickel will be made the subject of later papers. The rate of diffusion of carbon in gamma iron has been studied by Runge3 by Tammann and Schönert4, by Bramley and co-authors,5-14 and

Jan 1, 1940

By J. Randel Hill

The 64th Texas Legislature passed the "Texas Surface Mining and Reclamation Act," Chapter 131, Texas Natural Resources Code (subsequently referred to as "the Act"), at a point in time when little surface mining had taken place within the state. Thus, enactment of regulatory control governing mining operations in our state has, for the most part, preceded widespread, intensive mining activity. I should point out that the statute applies only to the extraction of coal, lignite, uranium and uranium ore. A recent opinion rendered by the Attorney General&apos;s office has stated that extraction of the named elements, when it occurs incidental to the extraction of other materials, e.g., clay, is not not an activity subject to the Act. An important theme of the Act, frequently overlooked in other environmentally oriented legislation, is recognition of the Act&apos;s affect on the mining industry. The Act states that "the extraction of minerals by surface mining operations is a basic and essential activity making an important contribution to the economic well-being of the state and nation" and, in reference to reclamation being accomplished contemporaneously with mining, provides a recognition that "the extraction of minerals by responsible mining operations is an essential and beneficial economic activity." This legislative recognition is, of course balanced against the need for proper mined land reclamation, the rights of surface owners, the need to guard against unreasonable degradation to land and water resources and numerous other actions or events that the Legislature wanted protected. Another rather pervasive general theme that is established in the Act is the concept that the agency is entitled to obtain whatever information, or take whatever action, that appears reasonably necessary to effectuate the purposes of the Act. This concept, coupled with the detailed requirements placed on mining operations in the portions of the Act dealing with Permit Applications, Reclamation Plan and Reclamation Standards, easily insures that surface mining activities can and will be regulated to the extent necessary. Section 131.102(b)(2) is probably the most relevant provision in the Act which deals with the preclusion of mined lands becoming waste lands. This portion of the Act states that the surface mining operator shall: ". . . restore the land affected to the same or a substantially beneficial condition. ." In this language the Legislature had made it abundantly clear that the abandoned or orphaned lands found in some of the Eastern states, will not be tolerated in this State, and provided the Commission with a degree of latitude to determine what condition would be appropriate in each individual mining situation. I bring this area of the Act to your attention because it is the area which has received the most inquiries and concern by operators, i.e. what does "substantially beneficial" constitute? The Commission&apos;s staff has spent a considerable amount of time wrestling with the statutory language "substantially beneficial" to determine the legislative intent and provide operators with guidance of what they can expect. In this regard, the most definitive criteria in our opinion lies in the Act&apos;s legislative hsitory. The Legislature had before it basically three reclamation standards namely: House Bill 656, considered to provide the most stringent reclamation standard and identical to Senate Bill 66; House Bill 1717 which was supported by industry spokesmen and was considered to contain the least stringent reclamation standard; and Senate Bill 55 which was adopted by the Legislature. During the Bill&apos;s initial hearing before the House Environmental Affairs Committee, the House sponsor of the Senate Bill 55, which was the Bill eventually adopted, made the following statement: (I am quoting verbatim from the Committee&apos;s transcript although substituting the speaker&apos;s reference to the authors names with the Bill&apos;s numbers.) "An example of the differing approaches of the four bills can be seen in the area of reclamation standards and this is critical. House Bill 656, talking about restoring the surface of the land, House Bill 656 has this statement: &apos;At least fully capable of supporting the use to which it was capable of supporting prior to any mining or any higher or better use.&apos; In other words you have to restore it to the level it was prior to the mining. Senate Bill 55: &apos;Restore the land to the same or substantially beneficial use.&apos; Substantially beneficial use. (Emphasis his) House Bill 1717 says: &apos;Restore insofar as practical to appropriate beneficial post-mining use.&apos; So that House Bill 1717 said to, &apos;restore insofar as practical to appropriate beneficial use. I think that&apos;s too weak, whereas I think the House Bill 656 that would call you to restore it to at least the use it had prior to the mining may also be too tight the other way. I think the Senate Bill 55 approach is down the middle of the road which says that you do restore it to the &apos;same or substantially beneficial use,&apos; is a proper way to go there." Therefore, the conclusion that we have drawn from the legislative history of the bill is that the extent of reclamation required by "substantially beneficial" may be something other than the use it was prior to

Jan 1, 1979

By Charles T. Holland, David A. Olsen

Considerable work has resulted in the development of a formula by which the strength of coal pillars for an L to T ratio of up to 12 may be estimated. One of the factors involved in this formula is the coefficient of friction between the coal pillar and the adjacent rock with which it is in contact. This paper presents the results of studies on sandstone, limestone, shale and coal and the coefficient of friction between coal and the other three under wet and dry conditions. With the coefficients of friction thus determined and the use of results obtained earlier by Meikle and Holland, it seems probable that coal pillar strength may be more closely estimated. Several investigators1-3 have found that the com-pressive strength of cubical coal specimens can be correlated by an equation such as

Jan 1, 1969

By W. N. Page

The Red-Ash colliery was the scene, March 6, 1900, of an explosion by which some fifty men were killed or wounded, and much property was injured or destroyed. On March 19th, the earliest date at which entrance was practicable, I examined the mine with the view of determining the extent, cause and point of origin of the explosion, and with the permission of Mr. F. Howald, the manager, and the owners of the property, for whom the examination was made, I present in this paper some results of that examination, comprising the essential portions of my report to them. Location and Plan of the Mine. The Red-Ash colliery, situated on the south side of New river, next below the Rush Run mine, with which the underground workings are connected, is a drift-mine, the entrance to which is on a slope, about 500 ft. above the river. (Fig. 1 is a plan of the workings, in which the points where human bodies were found are designated by numbers.)

Jan 1, 1901

By Lyndon L. Foley

The proper spacing of oil wells is a problem of vital importance to the oil industry. Conservation demands a maximum recovery, while economic considerations attach primary importance to profitable extraction of oil. Formulas have been evolved,1-4 which attempt to solve the spacing problem mathematically, using reservoir characteristics as factors. Comparisons have been made of fields producing from supposedly similar sands, which have been drilled to varying densitiesl5,6 and also of different leases in the same field. 5-8 Intermediate wells have been drilled in old, depleted fields to test the efficiency of drainage by the original operation.9-11 Intermediate wells have been drilled also to obtain cores of the depleted sand for analysis, from which to learn the degree of efficiency of extraction. The problem is being attacked by many students, and along several different lines. Unfortunately, the fields now depleted were produced generally without restriction, and conclusions drawn from them may not apply to fields operated under restricted production. Reservoir conditions in a restricted field, especially reservoir pressures and pressure gradients within the reservoir, are quite different from those in a field produced to capacity. Many people have held the idea that the closer the spacing, the greater the recovery. This general statement is not always true, as other factors than well spacing enter into the recovery problem. Cutler,5 who has been quoted frequently by advocates of close spacing, limited his conclusions to gas-drive fields, and to the particular fields and spac-ings that he investigated. Hill and Sutton7 analyzed four tracts in the Powell field; the tract most closely drilled had the third largest recovery per acre-foot, and the tract with the widest spacing had the second largest recovery per acre-foot. A search of the references to well spacing in the publications of the U. S. Bureau of Mines5,13-19 discloses repeated condemnations of the wastefulness of the practice of town-lot drilling.

Jan 1, 1938

By R. B. Tippin, J. S. Browning

The feasibility of multistage heavy liquid cyclone beneficiation of spodumene was successfully demonstrated in this investigation. The indicated recovery for the multistage circuits was mathematically estimated as continuous test runs would be necessary to determine the true influence of a middlings recycle. In the three-stage circuit, both the concentrate analysis and spodumene recovery exceeded 90%. The two-stage circuits were unable to simultaneously yield an acceptable produce with a satisfactory recovery. With the Nation&apos;s growing industrial mineral requirements, the U.S. Bureau of Mines has undertaken the task of investigating new mineral dressing techniques and improving the existing concentrating methods of ore beneficiation. One such project is the gravity concentration of minerals using heavy liquid separation (HLS).1-3 Heavy liquid separation is based on the simple principle that a material, whose specific gravity is less than the density of a solution, will float on top of the liquid and a material with a greater specific gravity will sink. Heavy liquid separation techniques were developed in the laboratory over half a century ago but the process has yet to be commercially adopted. In the past, commercial operations have failed because of numerous problems.4 Industrial interest has recently been reactivated because of engineering advances. The number and quality of the heavy liquids suitable for mineral processing has increased while the cost has sharply dropped. New and improved liquid recovery systems5,6 are under consideration with present emphasis on 1) solvent extraction, 2) thermo-evaporation, and 3) water washing. The toxicity of the heavy liquids7 presents a problem, but throughout the chemical and mining industries, many similar hazardous materials are safely handled. A distinct advantage of using heavy liquids is its ability to provide a near perfect separation of fine-sized mineral particles even when the specific gravities are close. Effective separations have been made on minerals down to 200 mesh and with a density

Jan 1, 1968

By Wallace E. Pratt

UNDER the stimulus of war psychology the American public has grown confused and jittery in its thinking on the subject of this nation&apos;s petroleum resources. This confusion arises from the failure of the average citizen, and even of many leaders in government, in our armed forces, and in the petroleum industry itself, to distinguish between our proved reserves of petroleum in the several oil-producing states and the total petroleum re- sources available to this nation. Leaders and public alike examine the accepted estimates of our proved reserves and thoughtlessly conclude that these estimates represent the total of our petroleum resources. Our fears are aggravated if we turn to the statistics on oil-finding and observe that the discovery of new reserves has waned decidedly in recent years. This confusion is dangerous because, under its influence, ill - considered policies spring up and flourish, choking out the most valuable fruits of the long experience of the American petroleum industry.

Jan 1, 1944

By C. F. Austin, J. K. Pringle

In view of the many large differences in structure and physical properties between metals, plastics, and most rock materials, a continuing experimental petrodynamics program has been established at the U. S. Naval Ordnance Test Station. Part of this program has been to test the concepts of scabbing and corner fracturing in a typical coarse-grained rock. The results of this experimental program have shown very interesting differences between the formation of fractures in rock and the formation of fractures in other materials such as metals and plastics which are often used as models for rock behavior studies. The gross behavior of coarse-grained brittle solids subjected to impulsive loading has undergone abundant empirical investigation by mining organizations and by mineral research agencies. However, the fundamental response of coarse-grained brittle solids to impulsive loading has received little detailed study in recent years. The various organizations and agencies interested in rock-like brittle materials have broadly applied the stress wave interaction concepts of the impulsive failure of metallic samples to the behavior of granular brittle materials 1,2,3,4,5,6 Using the metallic sample approach for stress wave induced fracturing, an understanding of the fracture behavior of brittle materials which perhaps is not always appropriate has been established in the open literature. An excellent summary of the metallic sample approach is provided by ref. 7 which summarizes the general beliefs prevalent at present regarding the impulsive behavior of brittle solids: "In the blasting process, rock breakage occurs primarily from tensile slabbing, beginning at a free face and proceeding back toward the explosive charge. The tensile waves formed by the reflection of incident compressive waves from two or more free faces will collide in the rock, resulting in large localized tensile stresses. Fractures formed by the interaction of these tensile stresses begin at the apex of the free face planes and progress back into the rock as shown...."

Jan 1, 1964