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By Cyril Stanley Smith

IsolatEd alloys of copper and silicon were prepared and examined by chemical methods more than one hundred years ago, but it was not until the work of Rudolfi l that the equilibrium relations were studied. The early history of the alloys was well described by Baradue-Muller 2 and need not be further discussed here. The diagram of Rudolfi, based entirely on thermal observations, showed sillcon to be soluble in copper up to 4.5 per cent. at 849" C., at which temperature there was a peritectic horizontal resulting from the formation of a ß phase with about 7.4 per cent. silicon from a and liquid with 7.85 per cent. silicon. The ß phase was believed to form a eutectic with Cu3Si at 820" C. and 9.8 per

Jan 1, 1929

By V 7. 0 / 300 dpi

DRILLING in the Oligocene potash basin of Alsace prior to 1927 had shown important differences of level in the salt beds thus encountered. To explain this a somewhat unsatisfactory hypothesis of faulting had been advanced. During the latter part of 1926 and the beginning of 1927- our firm was engaged by two organizations for the purpose of trying to supplement, by an electrical survey, the geological data thus far collected. As a re-sult of this exploration it was possible to affirm that salt dome structures were present in the Oligocene basin of the Upper Rhine, something heretofore absolutely unknown in that region. Two salt domes were actually outlined, one, near Meyenheim, was made the subject of a communication to the Academy of Sciences, by G. Friedel2; the other, near Hettenschlag, was briefly dis-cussed by C. and M. Schlumberger3 before the same academy. The purpose of this paper is to indicate the strati-graphic and structural conditions of the area where these salt domes were found; to discuss the results of the electrical survey which led to the location of the domes, and indicate the new geological outlook which such a discovery suggests.

Jan 9, 1928

By C. S. Duncan, S. Scuro, D. R. Muss

Work is vepurted which was aimed at accentuating the pec14liar attributes of the GaAs laser diode, namely its sutzull size and its high efficiency. This has been done by reducing- transport losses in the bulk p and n regions of the diode and combining many of. these diodes into series stacks with common optical cazlities. The result of this effort is a nearly monochromati source at about 8450A With a luminous areu 0.05 by The GaAs laser diode is an attractive pulsed light source in the near ir because of its ability to emit very large pulse powers and its small size. In addition to this, the device is efficient; and the higher the 0.05 cm emitting peak pulse po we rs at greater than 300 LC at repetition rates below 200 pps into a cone about 0.01 steradians when operated at 77°K. The results of nzeasuvetnents of peak optical power and spectra frorr~ these stacks are reported and some conclusions are drawn about the vole the individual diodes play in the stacked operation. peak output power, the more efficient it is. The limit for the amount of power that these diodes can emit is the transient and average dissipation associated with the pumping pulse. This power dissipation arises primarily from transport across the bulk regions of the diode; this fact, along with the relatively low thermal conductivity of the GaAs, led us to the conclusion that higher power

Jan 1, 1968

By J. J. Mike

During the past few years the combination of continuous billet casting with in-line reduction has been studied and several machines have been built with this capability included in the design parameters. (1,2,3,4,5) In-line reduction and continuous casting in combination are obvious and attractive. As pinch rolls are already in place for the continuous casting operation, it can be readily seen that a redesign of the mechanical and electrical equipment of the pinch rolls is all that is necessary to have in-line rolling. There have been numerous in-line reduction experiments conducted by simply increasing the pinch roll pressure on existing machines. (6,7,8,9) These generally failed to produce quality billets and often resulted in internal metallurgical defects (Figure 1).

Jan 1, 1972

By AIME AIME

EVEN the weather man joined in a friendly conspiracy to make the fall meeting of the Industrial Minerals Division at Rolla, Mo., Oct. 23-25. the splendid surges that it was. Following weeks of rain, the foliage of the Ozarks was still green, merely enlivened here and there by splashes of autumn coloring. In contrast to the tranquil beauty of the School of Mines campus under smiling Indian summer skies, the pace of the meeting was lively. Registration was larger than at any previous meeting and included an unusual number of prominent names and delegates from all over the country. From 125 to 150 were present throughout the three technical sessions, at the Thursday evening smoker, and also at the banquet on Friday; when students trooped in to the technical sessions the audience was augmented occasionally to over 200.

Jan 1, 1941

By DOOLITTLE E. M.

(Canal Zone Meeting, November, 1910.) The following notes are contributed, not with the idea of offering a complete history of the development of this very important process as applied to the Leadville district, but with the hope that the practice, as it was carried out in the Bi-Metallic Smelter, may still be of interest to others. The Bi-Metallic Smelter, at Leadville, Colo., was the first to make a commercial success of the process described in the following pages, which consisted essentially of smelting raw silver- and copper-bearing sulphide ores in blast-furnaces to form a matte, which was generally re-smelted with siliceous ores for a second high-grade matte. Robert Sticht, in his excellent monograph on the subject,1 has outlined briefly the plant belonging to this company. He says, in effect: The Boulder, Mont., enterprise set the example for others with whom the patentee (w. L. Austin) had been negotiating, and the old La Plata lead-smelter at Leadville, Colo., was fashioned into a crude, temporary experimental plant for the Bi-Metallic Company, and the feasibility of the process demonstrated by a trial run. Subsequently, the plant was considerably improved, and, being supplied with very favorable ores, continued to run without interruption from August, 1892, to June, 1893. In September, 1893, smelting was resumed in a completely remodeled establishment, some $200,000 having been expended upon the new work. Thus, aside from the Montana experiments, which, under the direction of W. L. Austin, began as early as- 1885 2 at Toston, and continued with indifferent success for six or seven years, the Bi-Metallic plant at Leadville may be said to have * Formerly Superintendent, Bi-Metallic Smelting Co. + Formerly Chief Assayer and Chemist, Bi-Metallic Smelting Co. 1 Modern Copper Smelting, E. D. Peters, 7th ed., p. 415 (1895). 2 Trans., xvi., p. 259 (1887-88).

Dec 1, 1910

INTERNAL The year 1976 was another outstanding year in the operation of the Institute and in the success of its varied activities. Total AIME membership reached 59,773 for a gain of. 6.4 percent. Total revenue increased to $5,111,2 10, up 22.4 percent, and balance sheet assets increased to $8,479,612, up 12.2 percent from the previous year. AIME and its constituent units conducted 30 technical meetings during the year, and attendance was up at most of them. Publications issued by the Constituent Societies continued a healthy growth. During the year 9 new local Sections were established, and at the end of the year the Institute had 150 Sections, with 19 of them overseas. Details on all of these operations are on pages 2 and 3 of this report.

Jan 4, 1977

By Charles H. Behre

KEYNOTE of the mining geology sessions was the preparation for an extensive war with all that this implies as to the need for strategic minerals, both metallic and nonmetallic. Nevertheless the sessions also included many papers of less urgent, more theoretical interest. The stress of wartime production had the effect of giving an unusually full and rich program, the longest in recent years, with sessions continuing virtually throughout the meeting. Some papers dealt with geophysical prospecting as applied to mining geology; others were concerned with the grand strategy of mineral reserves and thus involved the industrial minerals; such "borderline" subjects were presented before sessions held jointly with the Geophysics Committee or the Industrial Minerals Division.

Jan 1, 1942

By Thomas M. Plouf

Getting optimal performance from flotation cells can, in many cases, be critical to a project's economic viability. Simple testing procedures can sound early warning signals as well as maintain optimum recoveries from the flotation cycle. The materials required for a simple testing laboratory include: (1) pH meter or pH paper, (2) bottles of reagents used in plant flotation, (3) stop watch, (4) calibrated eye droppers. (5) laboratory flotation machine (1000-g tank, open impeller), (6) froth collection pans, (7) magnifying glass, (8) sizing screen sufficient to retain 10% of the flotation feed coarse fraction, (9) sizing screen for the size particles at which desliming of the plant flotation feed is to take place, and (10) a set of screens covering the complete range of feed particle size.

Jan 4, 1978

By R. C. Nelson, T. L. Weaver, A. I. Michals

This paper describes the design and performance of an apparatus for making continuous nondestructive resistance measurements throughout a spool of fine wire. Highly reproducible results on clean and graphite coated tungsten and rnolybdenum wires from 1 to 9.5 mil are presented. A linear relation between resistance and wire weight (per standard length) was obtained on clean wires, but only on those coated wires with very uniform coatings. Results indicating a correlation between tensile strength, hardness, and resistivity are reported. THE increasing demand for greater uniformity in fine tungsten and molybdenum wires destined for use as mandrels, grids, and coils in radio tubes and as filaments in light bulbs has rendered inadequate the standard (sampling) approach to the control of wire diameter and other physical properties. This ap-

Jan 1, 1961

By HORACE V. WlNCHELL

Location. THE St. Helens mining-district, indicated in sketch-map, Fig. 1, is chiefly in Townships 9 and 10 North, Ranges 5 and 6 East, of the Willamette meridian, in Skamania county, Wash. There is no railroad or even a wagon-road at present connecting it with any base of supplies; access is usually by wagon-road for FIG. I.-SKETCH-MAP OF THE STATE OF WASHINGTON. about 50 miles from the town of Castle Rock to Spirit lake, and from that point by pony-trail from 6 to 10 miles farther. History. Nearly 20 years ago two German farmers, totally inexperienced in prospecting, penetrated this region upon a hunting and fishing-trip. Their attention was drawn to numerous joints and crevices filled with black, glistening tourmaline, and con-

Oct 1, 1912

By John W. Buch

IN my review a year ago I pointed out that a small coal-mining companies as well as large had decided that the so called ?central shop? was a benefit. These central shops replaced in a large measure the commercial shops operated by those who have no direct connection with production of cod. Central shops in this time of salvage and major repairs have proved their worth. In addition, many of the larger companies had in their central shops equipment available for the production of many thousands of parts for our vast war machine and, as subcontractors, are doing this type of work. This is a real contribution to the war endeavor. Lack of new supplies has resulted in exhaustion of those stocks formerly stored or hidden in underground shanties. This means that the small stock of repair parts likely LO be available to any mine

Jan 1, 1943

By Jay A. Carpenter

THIS preliminary report from the Committee to Study Relations Between Students and the Institute is submitted to our member- ship for consideration and discussion before the general subject comes up for action at the Annual Meeting in February. At present, the A. I. M. E. has a dual relationship with mining students, each relationship in no may connected with the other. To the individual student the Institute offers for $2 a year a Student Associateship in the Institute which carries with it a subscription to MINING AND METAL- 'LURGY, a watch fob, and the privilege of becoming a Junior Member after graduation without payment of the -first year's dues, if one's application is accepted. To the student's college society it offers the privilege, upon application, of becoming 'an Affiliated 'Society, which brings with it no specific supervision or aid, and in turn requires no specific conditions as to membership, fees, or rules. This Affiliated Society is distinctly a school organization which Student Associateship in the Institute can he given special status or ignored, is the local .society sees fit.

Jan 1, 1934

By T. D. Yensen

EFFECT OF ELEMENTS ON MAGNETIC PROPERTIES OF IRON THE elements aluminum,1 arsenic,2 silicon,3 tin2 and vanadium,4,8 when used in relatively small amounts as alloying elements, seem to have a beneficial effect on the magnetic properties of iron-i. e., they increase the maximum permeability and decrease the coercive force-whereas there are definite indications that boron,5 carbon,6 nitrogen,7 oxygen,8' phosphorus,6 sulfur6 and titanium,4 as well as the metals of and adjacent to the ferro-magnetic group, nickel,9 cobalt,10 copper,11 and manganese,6 have a detrimental effect on these properties. The effects of calcium4 and magnesium4 are small, if any, while the effect of chromium 12 in small amounts is unknown and in large amounts is generally detrimental.

Jan 1, 1931

By B. J. Reid, J. N. Greenwood

It has been shown1 that cavities are formed in the grain-boundaries of copper and 70:30 brass (as well as in magnesium) by the application of tensile stresses at elevated temperatures. For a given rate of strain, cavities are formed in brass at a lower temperature than in copper, and they are larger; it was thought that this earlier onset of cavitation in the alloy might be caused by the distortion produced in the metal lattice by the alloying element. If the cavitation is caused by the vacancy-migration mechanism, ' the distortion of the lattice would reduce the energy required for vacancy formation, and thus provide vacancies more readily to assist in the cavitation process. It was decided to study a range of alloys to find out whether increasing amounts of an alloying element would cause any progressive increase in, or modification of, the cavitation in copper. Nickel was chosen for this purpose, since it is soluble in copper throughout the whole range of alloys. A further advantage was its low vapor pressure, which enabled the preparation of the alloys in vacuum and the consequent reduction of their hydrogen content. It has been suggested that cavities may be nucleated by the migration of hydrogen atoms to the less regular atomic spacing at the boundary, and their combination to form molecules. The latter being too large to diffuse back into the lattice, form stable cavities into which vacancies could condense. PREPARATION OF ALLOYS All alloys, ranging from pure OFHC copper to 43.7 at. pct of nickel (carbonyl), were prepared in a vacuum furnace employing high-frequency induction heating. When a charge was melted, vigorous gas evolution occurred initially, after which the pressure was reduced to 10-4 mm Hg, using an oil-diffusion pump. After remaining molten for a further 1/2 to 1 hr to aid degassing, the melt was allowed to solidify in the crucible. In this way contamination by gases evolved from the surface of a separate mold was avoided. The list of alloys prepared is shown in Table I. The percentage of hydrogen present in the OFHC copper was reduced from 0.0054 at. pct to 0.0012 at. pct, as measured by a vacuum-fusion method. The alloys were cold-rolled to 0.03-in.-thick strip, and were homogenized in vacuum for 1 hr at 900°C after every 30 pct reduction. At a thickness of 0.05 in., the strip was held at 450°C for 24 hr under high vacuum (10-5 mm Hg) in an attempt to reduce the hydrogen content still further. Tensile specimens were prepared with a gage length of 1 in., and were finally annealed for 2 hr at 800°C to give an average grain diameter of 0.1 mm. TENSILE DEFORMATION The specimens were deformed in a tensile straining machine operated by a synchronous motor at a constant rate, equivalent to 1.7 pct per hr on a 1-in. gage length. The specimen and grips were contained in a vacuum jacket. A pressure of 10-2 mm Hg was maintained, which was sufficient to prevent surface tarnishing of a specimen held at 650°C for 24 hr. Tests were made between 20. and 650°C and the temperature was controlled to within ±3° over the gage length. The load was measured by the deflection of a cantilever spring. a) Mechanical Properties-The ductility curves shown in Fig. 1 fall into two groups. Figs. 1(a) and (b) for copper and the 5 pct nickel alloy, respectively, show a continuous fall in ductility with a steep fall between 200° and 400°C. Figs. l(c) to (f) show the same sudden loss of ductility between 200° and 400°C. With higher temperatures, however, there is a recovery in ductility values to a maxi-

Jan 1, 1959

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'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'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'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'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'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's transcript although substituting the speaker's reference to the authors names with the Bill'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: '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.' In other words you have to restore it to the level it was prior to the mining. Senate Bill 55: 'Restore the land to the same or substantially beneficial use.' Substantially beneficial use. (Emphasis his) House Bill 1717 says: 'Restore insofar as practical to appropriate beneficial post-mining use.' So that House Bill 1717 said to, 'restore insofar as practical to appropriate beneficial use. I think that'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 'same or substantially beneficial use,' 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 David P. Shoemaker, Clara B. Shoemaker

It has been shown for an important class of complex transition intermetallic compounds (a, P, R, 6, and p phases) characterized by "normal" coordination [CN12 (icosahedral), CN14, CN15, CN16/ that interatomic distances nay be calculated to a good approximation as the sum of characteristic atomic radii. Two radii, one for major ligands and one for minor ligmds, are specified for each atom, except in the case of CN12 where only a miaaor-ligand radius is specified. The same appears to be true of transition-metal phases of simpler struc-ture: Laves phases (CN12, CN16), and p-tungsten phases (CN12, CN14). In the case of known examples of the more complex phases, a simple rule is given which specifies these radii. However, only a fraction of the known examples of the simpler phases obey this rule closely. To include the latter phases the rule may be modified by considering the radii as linear functions of the weighted average of the Pauling CN12 radii of the two kinds of atonzs, with the radii weighted according to the over-all chemical composition of the alloy. With very few exceptions interatomic distances for both tlze complex and the simpler transition phases can b$ predicted with this modified rule to within 0.06A. ManY intermetallic compounds are known of composition A,By, in which A is a transition element to the left of the manganese column in the periodic table and B is a transition element in or to the right of it. Frequently the coordination numbers (CN) found in these compounds are CN12 (icosahedral), CN14, CN15, and CN16 (called "normal" coordinations by Frank and Kasperl). Well-known examples are the cubic and hexagonal Laves phases which have CN12 and CN16, and the 0-tungsten (CrsO) phases which have CN12 and CN14. In the more complicated (often ternary) phases, such as the a phase,2 the Beck phases p3 and R~, the 6 phase,5 and the p p atoms occur with CN12, CN14, CN15, and (except for a) CN16; in many cases several crystallographically independent atoms of one particular CN occur in the asymmetric unit. A large number of independent interatomic distances are found in these complicated phases, varying from 20 in the a phase to 94 in the 6 phase. These distances show a large spread; they vary, for example, from 2.358 to 3.278A in the 6 phase. In our analysis of these distances we found that in each of these compounds every atomic position can be characterized by either one or two radii. The CN12 positions are characterized by a single radius, The higher coordinated positions are characterized by two radii, namely: the CN14 positions by 4 in the direction of the twelve "5-coordinated" ligands3 (called 'minor" by Frank and Kasperl) and by r:, in the direction of the two "6-coordi-nated" ligands (called "major" by Frank and Kasper); the CN15 positions by r15 for the twelve minor and r:, for the three major ligands; the CN16 positions by rlE for the twelve minor and r:, for the four major ligands. We have expressed the experimentally determined interatomic distances in observational equations as the sums of the appropriate pairs of these characteristic radii and the value of these radii have been determined by the method of least Squares. Despite their wide range, the interatomic distances could then be predicted by the sums of these atomic radii with an average deviation in any one compound of 0.06A or less. The results are summarized in Table I. Inspection of the radii thus obtained shows that in the structures in Table I the radii (in A) are given to a first approximation by the simple relationship: Where CN is the coordination number (12, 14, 15, or 16), and A = 1 for major ligands and = 0 for minor ligands. The interaLomic distances can be predicted within about 0.1A by sums of these atomic radii. Another phase belonging in this group with CN12, 14, 15, and 16 is the y phase & B7, in which A is molybdenum or tungsten and B is iron or cobalt. Recently the M%C phase has been refinedE and the observed distances also agree well with those calculated with Eq. [I]. (In the original determination of the structure of W6FeV7 the F$(II)-W(II1) distance was erroneously given as 2.84A, but we have recalculated it fro? the published parameters and found it to b? 2.57i4, in good agreement with the value of 2.6A predicted with Eq. [I.].) Many binary transition alloys are known to crystallize with the simpler structures having "nor-

Jan 1, 1964

By N. I. Fisher, J. Shepherd

A rapid method of determining natural fracture trends in collieries has been developed. The method will yield information that is precise enough to permit fracture domain boundaries to be delineated in a coal seam. Instead of a survey of cleat trends in a colliery taking several man-weeks or even man-months, a reconnaissance survey can be carried out in only a few man-days. At each of a sequence of sampling sites along a traverse, five measurements of trend are recorded for each set of fracture directions. A sequential plot of the medians of each fracture set is then made manually underground or by a computer in the mine office. Changes in fracture pattern can be detected easily in colliery development work if a geologist visits advancing faces regularly, and forecasts can be made about the likelihood of forthcoming faults and dykes. A full description of this method is given in Shepherd and Fisher (1981). The concept of mapping fractures rapidly in a colliery is based on using a geological traverse (Compton, 1962), along which observations can be made at chosen, regular intervals. The technique has been widely used for surface mapping across outcrops and in follow-up work in photogeological studies (Hepworth and Kennerley, 1970). In these cases, the geologist surveys the traverse line as mapping proceeds. In a colliery, however, ready-made traverse lines already exist in panels and along main roadways, often in several directions. It is thus possible to traverse a colliery in different directions and record the fracture trends at intervals, generating a reconnaissance fracture map. This can also be done on a continuing basis as mine development takes place. Generally, a sampling traverse should be longer than 0.5 km with sampling sites at relatively close-spaced intervals along the traverse. For example, in room-and-pillar mines pillars are commonly formed on 40-m centers and the sampling sites can then be arranged at 20-m intervals [(Fig. 1)]. The sites might have to be closer together for mines known to have bad mining conditions. The predominant fracture trend is normally the face cleat and the subordinate trend is the butt cleat (McCulloch et al.. 1974). Various changes can occur in the cleat or joint pattern: the face and butt sets may disappear or an entirely new set or sets may appear. Therefore, it is best to record all prominent fracture sets. Sometimes there is only one; in other cases there may be as many as three or more. An odd number of measurements of each fracture set are made (generally five or more) to enable the median value to be determined easily. The median value can be plotted underground using graph paper or a computer plot can be made in the laboratory or mine office [(Fig. 2)]. The sequential linked median (SLIME) plot draws the median trend for each sampling site as a unit line segment. The segments from successive sampling sites can be connected together to form a long chain [(Fig. 2A)]. The needle plot, on the other hand, draws a straight line to represent the traverse and then plots out the median trend for each sampling site [(Fig. 2B)]. The SLIME plot is better for visual display, as it highlights small irregularities and gross changes in trend. However, some work is required to relate the individual segments to their site location along a traverse. In this respect, the needle plot is more convenient because each segment -can be plotted-at a point corresponding to its location. Also, there is precise match-up if needle plots of face and butt cleat are compared. A description and listing of the SLIME program is given by White et al. (1981). An example of the use of this method is given for Wallsend Borehole colliery in New South Wales (Australia) [(Fig. 2)], where domains II and IV are associated with mining hazards. Domain II is coincident with a normal fault of 2.6-m throw, and domain IV with a basic dyke 12 m thick. These hazards were approached driving in a southwesterly direction, and a pronounced change in trend of the cleat to a northwesterly direction occurred at a distance of approximately 45 m from each one. The northwestern joint trend is parallel to that of the dyke and fault, and it occurs at a higher frequency close to these structures. The association of a particular joint set with faults has been found elsewhere (Shepherd and Creasey, 1979). The two minor cleat direction changes within domain V are narrow joint zones that are less than 5 m wide. The fracture trends derived from a SLIME traverse can be verified by collecting larger quantities of data at selected sites, as shown in the balloon density (rose) plots depicted in [Fig. 2C]. We are grateful for the financial support provided by Thiess Bros. Pty. Ltd. and the National Energy Research, Development, and Demonstration Program administered by the Commonwealth Department of National Development and Energy. R.W. Miller Holdings Ltd. and Thiess Bros. Pty. Ltd. are thanked for their permission to publish data from their collieries.

Jan 1, 1982

By R. E. Mussler, F. E. Block, T. T. Campbell

An exploratovy study was made to deternzine the feasibility of preparing beryllium by the metallother-. mic reduction of beryllium oxide. The procedure involved heating a relatively nonvolatile metal reductant in contact with beryllium oxide in a vacuum. Beryllium vapors formed in the reaction were condensed as a coherent deposit on a heated surface. Reductants tested included tanthanun, yttrium, thorium, Th-Mg, and Zr- Ti alloys, and the hydrides of lanthaniir~z, yttriunz, and zirconiur?7,. Test ten7pevatures ranged from 1350'to 175O' C, and reaction times ranged frot 30 to 100 lzr. In most cases metal recoveries were lola, although yields close to 90 pct of theoretical were obtained with latzthanum, yttrium, and zirconium reductants. In most cases metal deposits were contanzinated by beryllides, /ls/cally of the Beln M or Bel3 M type. BERYLLIUM has a variety of unique properties including light weight (sp gr 1.85), low thermal neutron absorption cross section, high scattering cross section, excellent dimensional stability, high strength to weight ratio, high melting point (1285"C), high specific heat, and high thermal conductivity. Interest in beryllium as a structural material in aerospace and nuclear-reactor applications is based on these properties. In general, the potential of beryllium has been only partially realized, largely because of the brittleness of poly crystalline forms of beryllium, difficulties associated in its fabrication, and joining problems encountered in its use in structural applications. Several excellent books and monographs are available to those interested in the occurrence, extractive metallurgy, and utilization of beryllium.1"* Although an extensive amount of research on beryllium has been in progress during the past 10 years, much of the work has been concerned either with the so-called "ductility problem" or with the development of methods of fabrication and evaluation of properties of various commercial or purified grades of metal. A recent survey of the literature indicates that only limited efforts are presently being directed toward developing new methods for reducing beryllium compounds to metal. Two major commercial methods now used to produce beryllium are the magnesium reduction of beryllium fluoride and e lec trow inn ing of beryllium from fused sodium chloride-beryllium chloride salt baths. Only a limited amount of work has been done on the direct reduction of beryllium oxide. Major factors which complicate this method are the great stability of beryllium oxide and the reactive nature of beryllium metal. The stability of the oxide necessitates extremely high reduction temperatures and vacuum operation to liberate beryllium metal vapor and cause reactions of the following type to proceed: XBeO(s) +YM(s)-MYOX(s) + XBe(& As early as 1939, roll' used this reaction for the direct reduction of beryllia by zirconium and titanium, and later in 1952 ~a~el~ studied the reduction of beryl-

Jan 1, 1967

By Oscar Lee

RESERVE Mining Co., owned jointly, by Armco Steel Corp. and Republic Steel Corp., controls 9% miles of magnetic taconite ore on the eastern end of the Mesabi Range lying between Mesaba and Birch Lake. The ore reserve which can be mined by open pit methods is conservatively estimated at 1.5 billion tons under a shallow, loose overburden requiring no rock stripping. Taconite now being mined is in the upper cherty horizon. It has been metamorphosed by the intrusion of gabbro and most of the iron oxide is altered to magnetite. The nonmagnetic portion of the iron is practically all in the form of silicate. The magnetic iron is finely disseminated through the rock and requires grinding -150 mesh for clean liberation of the iron oxide from the gangue.

Jan 5, 1954