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By Thomas M. Turner

Open pit mining, always a demanding task, faces two relatively new problems today: (1) availability of equipment and (2) environmental restrictions. The modern dredge offers relief in both problem areas. Delivery on a major dredge might run 18 to 24 months rather than 60 months; and lowering of the water table is precluded, thus minimizing environmental objections. In addition, a lower first cost and potentially increased efficiency may offer real advantages to the miner who is forced away from his traditional mining methods. What are the objections to the use of a dredge in open pit mining? Perhaps first and foremost is the natural reluctance to change from a successful operation. Who can blame the miner who has developed expertise in the use of the dragline if he is reluctant to change to a new mining technique that requires new and different skills? A part of the same problem is the miners' desire to control the excavation visually in order to delineate sharply between overburden and matrix. This problem can be alleviated significantly by utilizing good boring data and a positive acquisition cutter. In the final analysis, however, if the miner is prohibited from dewatering the area, either he mines the deposit by dredge or not at all. There is little doubt that when the decision is made to remove overburden and/or matrix by dredge, the problems of delineating between overburden and matrix, creation of slimes, and development of mining plans to minimize double handling etc., will be addressed and solved. There are two broad categories of dredges: mechanical and hydraulic.

Jan 1, 1976

September 20, 1917. As this meeting terminates the year's agreement under which the Engineering Foundation has appropriated its income to the National Research Council, a brief summary of what has been accomplished seems called for. The Research Council was organized Sept. 19, 1916. The Executive Committee was appointed at that meeting; since that date two other meetings of the Council have been held, one in Boston, on Nov. 13 and 14, the other in Washington on April 19. During the intervals between the meetings of the Research Council, the Executive Committee has conducted all of the business of the Council. There have been 29 meetings of the Executive Committee, 13 in New York up to the first of May, 15 in Washington subsequently, and one in Boston. The meetings in New York were devoted to the organization of the Research Council and especially to appointment of committees. At the outset, the Council had no very clear idea of the way in which it was to organize; there were several other groups of scientific men at work, among them, the Research Committee of the American Association for the Advancement of Science and the Engineering Committee of the Advisory Commission to the Council of National Defense. Time was spent in straightening out these two principal complications, both of which were satisfactorily adjusted. The upshot of these negotiations is to leave the Research Council as the only representative, national body of research men, assisting the Government. During the period up to May, the Executive Committee in New York selected carefully the personnel of some 25 principal committees, and of a large number of sub-committees; so carefully were these chosen that of the entire number, several hundred, there have been only one or two declinations. Some of the important steps in the development of the Research Council are the establishment of the Military Section, composed. of the members of the Council connected with the Government and resident in Washington. This Section put the Research Council into close contact with the most important officials of the Army and Navy. From it has grown the Washington office of the Council, and the recognition of the Research Council as the "Department of Science and Research of the Council of National Defense; " and the establishment of the Washington office after the Council of National Defense had officially recognized the Research Council. About this time Dr. Hale, Chairman of the Council, appointed Dr. Millikan to be Vice-Chairman to represent the Council in Washington, and Dr. Millikan has since then been in charge of the work of the Council. At the request of the Secretary, Dr. Millikan has prepared a brief report of some of the work of the Research Council during its first year, which is appended to this report. It shows that the Research Council has been active in much of the important work. under way in our preparations for war, and that it has rendered effective services to the Government.

Jan 12, 1917

A. SILVERMAN,* Pittsburgh, Pa.-Prof. Richards has described a very interesting process. In addition to the method described, electroplating and a number of other processes have been used. In one, the two metals were heated and united under hydraulic pressure; in a second, the steel was coated with an alloy, brass for example, and the molten copper cast around this. The process that I would like to bring to the attention of the metallurgists present consists simply of pouring molten copper, brass, or cupronickel around a clean red-hot steel billet. 'It is covered by the Roth patents. The 8-in. cylindrical billet containing about 70 per cent. steel (core) and 30 per cent. copper is hot drawn or rolled until several inches in diameter and afterward cold drawn or rolled to rod, wire of any desired diameter, or sheet. The wire is used for electrical conduits where conductivity and high tensile strength are required, also for the manufacture of cables and screen cloth. The sheet is employed for the manufacture of spouting, molding, shells, etc. The last application is particularly interesting. In testing rifle cartridges, which usually contain lead-filled copper noses, pine boards 1 in. thick, covered with ¼ -in. rawhide, are placed 1 ft. apart. The value of the cartridge depends on the number of boards penetrated by .the bullet. In government tests made with copper-coated steel noses (15 per cent. copper on either side of the steel) the penetrating power was found to be approximately double that of pure copper noses. The advantage of copper-coated steel over cupronickel lies in the fact that the- former does not require any special heat treatment during the punching. Rifle cartridges were prepared from copper-coated steel in a number of government arsenals. The value of the combination was attested by the awarding of a contract for the construction of a $3,300,000 plant. Unfortunately, the contract was signed on the day preceding the signing of. the armistice and was cancelled several days later. Tests were conducted for about 1 yr. before the contract was awarded to determine the value of this combination of metals. Since the war a number of cartridge and shell manufacturers have signified their intention of using copper-coated steel.

Jan 4, 1919

By A. E. Dwight, P. A. Beck

A search was made for ordered phases of AB3 composition in various combinations of Ti- and V-group elements with CO-and Ni-group elements. Three new TiNi3-type phases ZrPd3, HfPd3, and HfPt3 were found. In addition, twelve new Cu3Au-type phases TiRh3, Tilr3, ZrRh3, Zrlr3, HfRh3, Hflr3, VRh3, VIr3, CbRh3, Cblr3, TaRh3, and TaIr3 were also found. The lattice contraction for all three structures considered increases with increasing relative size of the A atom, suggesting that it is mostly the A atom that cont~acts. It was noted that, for the same radius ratio the lattice contraction is larger when the A atom is Ti than if it is Cb OY Ta. It is well known that elements or disordered solid solutions, which have structures with spherical close-packing, may be described in terms of various stacking schemes of close-packed layers. Stacking of the type abab corresponds to the hexagonal close-packed structure, and stacking of the type abcabc corresponds to the face-centered-cubic structure. In binary alloys of the first, second, and third long period transition elements various AB3 phases occur with close-packed ordered structures. It was observed that these ordered structures also may be described by suitable stacking of close-packed ordered layers, Fig. 1, as first shown by Laves and Wallbaum for TiNi3.' It is clear that the units of translation in such a close-packed layer consist of four atoms, one of which (black circle) is atom A and the three others (empty circles) are atoms B. Because of the alternation of A and B atoms in every second row of each layer, the unit-cell dimension in the layer is equal to the sum of the diameters of atoms A and B: a0 = 2(rA + rB). Stacking of such layers in the sequence abab results in a hexagonal close-packed structure of the MgCd, type. The unit-cell dimension in the basal plane is approximately double of that for the disordered hexagonal close-packed structure, but in the direction of the hexagonal axis it is about the same, so that 2co/uo = 1.63 in case of spherical close-packing. Ordered hexagonal close-packed structures of this type were found to occur in MoCo3,2 WCo3,, and UPt, .4 When the ordered layers shown in Fig. 1 are stacked according to the scheme abcabc, the resulting ordered structure is of the AuCu, type (cubic). Structures of this type were found to occur in TiPt3,5 CrPt,,' CrIr,,' and URu, .4 Finally, the stacking scheme abacabac of the same ordered layers results in a hexagonal close-packed structure of the TiNi3 type.' In this case, the unit-cell dimension is doubled not only in the basal plane, but also in the direction of the hexagonal axis, so that co/ao = 1.63. Structures of this type were found to occur also in TiPd3,5 ZrPt,," and UPd,.4

Jan 1, 1960

By J. M. Locke

Bruckner's revolving cylinders for roasting ores, etc., are now used at a number of the mills in Colorado and New Mexico, for the purpose of roasting and chloridizing silver ores, with highly satisfactory results, even from those cylinders of small size, erected before the many improvements of recent date. AS examples of the larger improved cylinders, reference can be made to those erected at the Tennessee Reduction Works, Silver City, Grant County, New Mexico, and those which were built, in 1871, at the celebrated Caribou Silver Mill and Mines, Colorado, a mining enterprise which has proved so satisfactory as to have been lately sold to a Holland company for an enormous amount. These cylinders, as now constructed by Messrs. Lane & Bodley, of Cincinnati,,Ohio, are shown in Plate 111, in which Fig. I is an elevation in perspective, Fig. 2 a longitudinal, and Fig. 3 a transverse section. Fig. 4 is a sketch of a mill, with Bruckner's cylinder. The exterior of the cylinder is a shell of boiler iron, 12 feet long by 5 feet 6 inches in diameter. The ends are partially closed with similar material, leaving in the centre a circular opening about 2 feet in diameter, bounded by a flange projecting several inches. Upon one side is placed an opening closed by a hinged door. Upon the outside of the cylinder are bolted three bands, as shown in Fig. 1, in which the section of the first is square, and that of the third semi- . circular; the second, or middle band, is a strong spur gear. Passing through the cylinder are six pipes parallel to one another, in a plane at an angle of 15" to the axis of the cylinder; these pipes also lie in this plane at an angle of from 30" to 35' to the longitudinal .axis of the plane, as shown in Fig. 2, where the internal arrangement of the cylinder is seen, a perforated diaphragm being formed through part of the cylinder by means of perforated plates placed between

"The power development at these falls, three miles below the city of Great Falls, was made in 1891 by the original Great Falls Water Power & Townsite Company, and the Boston & Montana Consolidated Copper & Silver Mining company, the predecessor of the Boston & Montana Reduction Department mentioned above.The dam is 746 feet long, placed a short distance above the crest of the falls, and giving an effective head, as now constructed, of from 42 to 44 feet. There are power houses on both banks, those on the south bank belong to the Great Falls Power company, the successor of the Great Falls \!\Tater Power & Townsite Company, and the Great Falls Electric properties. The water is led from the dam to these power houses through sheet iron pen-stocks the water wheels are of the horizontal turbine type, and of various sizes.The water is here carried from the dam to the power houses by an open canal or headrace, the walls of which are concrete. This headrace is 100 feet wide at the widest point. The available head was originally less than 40 feet, but this was increased to about 44 feet by means of flashboards and tailrace wall, seperating the tailrace from the main river and delivering the water to the river at a considerable distance below the power house, thus taking advantage of a considerable fall in the river below the sheer fall at Black Eagle.A total of about 12,000 horse power 1s developed at these falls, the Great Falls Power Company, and Great Falls Electric properties developing about 2,000 horse power, and the Anaconda Copper Mining Company developing the balance."

Jan 1, 1913

By R. D. Carter

Methods are presented for calculating the performance of multiwell gas reservoirs. These methods account for two-dimensional, unsteady-state flow of a non-ideal gas through a heterogeneous formation. The performance can be obtained for gas reservoirs with known physical properties and configuration subjected to specified development and production schedules. These methods may prove helpful in optimizing the exploitation of gas reservoirs. The numerical solrrtion procedures given for this non-linear problem are extensions of known techniques for the linear diffusion equation. Two of these procedures are based on a new difference equation given by Saul'ev. Limitations and advantages of these procedures are discussed. An example solution is presented and is used to compare the calculation methods. INTRODUCTION Li planning the operation of a multiwell gas reservoir, it is desirable to predict its performance for each alternate development and producing schedule under consideration. This paper presents three numerical procedures that can be used to calculate such gas reservoir performance using a digital computer. These methods account for two-dimensional transient flow of a non-ideal gas within the reservoir. Extension of these methods to three-dimensional flow is possible. The paper is divided into three parts. The first describes the problem for which a solution is wanted and three numerical procedures that can be used to obtain solutions. The second discusses the information necessary to set up a problem. This part will be of greatest interest to the field engineer. The third gives data and results for an example problem. PROBLEM AND SOLUTION METHODS In the following development, a gas reservoir is regarded as a sealed, porous, permeable, heterogeneous body in which a single, non-ideal gas phase is flowing. Flow is permitted in the x- and y-horizontal directions, but is considered to be negligible in the vertical or z-direction. The reservoir can be tapped by one or more wells. Methods to be described provide a basis for calculating the complete performance of the reservoir, including rates and cumulative production from the wells, and pressure distribution and decline in the reservoir. If the isothermal flow of a non-ideal gas obeying Darcy's Law occurs in two dimensions in a region R, the governing equation in this region is:

Jan 1, 1967

By Henry E. Armitage

The object of this paper is to give a few useful hints on the concentration of low-grade ores. The machines that I shall speak of are, Cornish rolls, revolving screens, Hartz jigs, spitz-lutte, and the Linkenbach buddle (or Roberts's patent buddle, as it is called in Colorado). I think the reason why some of them have been discarded in favor of more recent inventions is that they have not been given a fair chance to do their work in a satisfactory manner. Cornish rolls are usually looked upon as a machine designed simply to crush the ore as a preliminary to sending it to the sizingscreens, beyond which they have nothing to do with dressing the ore. On the contrary, the rolls give the key-note to the whole process. It is well known that one class of rock will crush differently from another, and from the result obtained by passing the ore through the rolls the size of the first revolving screen and the surface required on the jig-screens must be determined. If it is found that the mineral crushes clear from the quartz, a large mesh can be used on the first sizing-screen, and the tailings will not require recrushing ; but if it is found that some of the tailings from the first jig are ragged (that is, are carrying off particles of mineral sticking on the quartz), it will be necessary to recrush them. Again, if a large percentage of the tailings carry off mineral, it will be more economical to commence with a finer mesh screen than to recrush the tailings. Having determined the best mesh to use on the first sizing-screen, the different sizes on the other screens can be determined from it. I have found for practical purposes that, commencing with a 6-mesh, the next should be 8, then 12, and finally 18. The holes in the jig-screens should be a trifle larger than in the revolving screens. For instance, if the revolving screen is made of No. 14 wire, the corresponding jig-screeus should be of No. 16 wire. The jig-screen surface required for each size made depends on the may

Jan 1, 1890

By Robert C. Munro, Kenneth M. Reim

NEW IDRIA INTRUSIVE For the most part this ultrabasic mass is a highly sheared serpentine, the exposed rock being made up of small serpentine chips and plates, the faces of which have been slickensided. Throughout this sheared material there are residual blocks of serpentine and highly to moderately serpentinized peridotite. The faces of these resistant blocks show rounding and slickensiding and their size varies from pebble size to diameters of over 5 ft. Certain areas have seemingly resisted the shearing stresses and remain as moderately fractured serpentine. Throughout the ultrabasic mass are bodies of silica-carbonate rock, silicified serpentine and minor concentrations of magnesite and chromite.

Jan 9, 1962

By Toyohiko Hirota, Fukuo Itoh

Oil and natural gas aside, sea floor mineral resources currently being exploited in Japan are offshore sand and gravel and deep-sea manganese nodules. The mining of sand and gravel has already started. With regard to manganese nodules, the geophysical investigation and the study of the mining method are also underway. This report outlines the activity of a few Japanese firms, the Deep Ocean Minerals Association formed by some 30 private firms, Government agencies, a public corporation and two government research institutes. Researches on new exploration instruments, properties of deep-sea sediments and the mining method currently conducted by the National Research Institute for Pollution and Resources are described in detail.

Jan 1, 1976

By A. R. Troiano, W. J. Barnett

The existence of a grain size stabilization effect on martensitic type reactions as shown by Scheill in an iron-29 pct nickel alloy and by Troiano and Tokich2 in cobalt prompted a review of other martensitic reactions to determine if this stabilization effect is characteristic of all martensite type reactions. Preliminary work has shown this effect to be present both in the gamma —+ epsilon transformation in an iron-20 pct manganese alloy and the martensite transformation of SAE 4140 and 3 pct Cr-O.40 pct steels. No appreciable effect was found in an SAE 2340 steel. The M, temperature for the gamma —+ epsilon transformation was lowered from 380°F to about room temperature by varying the annealing treatment following cold work as shown in Table I. The effect of austenitic grain size on the M, of three steels is shown in Table 2. M, was deter- mined by the conventional quench-temper method of Greninger and Troiano. In a single crystal the change in external shape concomitant with the homogeneous shear mechanism of the martensite transformation can take place unhindered. In a polycrystalline specimen a restraint of these changes must occur at the grain boundaries. Therefore, the smaller the grain size the greater the shear strain energy necessary for the formation of a martensite crystal. The degree of lowering of M, due to the reduction of grain size is much greater when the change in crystal structure involves only a small energy change, such as face-centered cubic —+ close packed hexagonal (that is, CO and Fe-20 pct manganese alloy). The maximum lowering of M, observed in the steels investigated was 50°F with a change in the ASTM austenitic grain size of 1-2 to 8-9. In comparison, the crystal structure change face-centered cubic —+ body-centered tetragonal involves a considerable energy change. There is little doubt that with much finer grain sizes the increased grain boundary restraint would greatly enhance this stabilization effect. The implications of this phenomenon are multifold. Undoubtedly. under certain conditions it offers a method of stabilizing high temperature phases for room temperature

Jan 1, 1949

By Thomas A. Edison, John Birkinbine

The Transactions already contain many valuable papers on the subject of ore-concentration, but with reference more to the treatment of other ores than those of iron. In this country much money, labor and thought have been devoted to the enrichment of iron-ores by roasting to drive off sulphur and carbonic acid, eliminate water, or make the ore more friable, and by washing and screening to remove the clay and sand from earthy ores. In concentrating magnetites and hematites more has been done than is generally believed; but, unfortunately, the results up to the present time have not been encouraging. On the contrary, so many attempts have proved unsatisfactory that any system of concentration is now unjustly looked upon with doubt, and the problem presented to individual mines must therefore be approached with caution. For many years the magnetites of the Adirondack region of New York State have been roasted, reduced to proper size by means of gang-stamps, and jigged on screens in water. Latterly plunger-jigs and rotary-jigs have been introduced, and in some places crushers and rolls have taken the place of stamps. In one instance in that region a plant for reducing the ore by crushers and rolls and separating it by magnetism was put up to treat a titaniferous ore; but, the titanium occurring as ilmenite, the result was unsatisfactory, and the plant is now being reconstructed at another mine, where apatite and silica are to be separated from the magnetite. A large concentrating works was erected at Negaunee, Michigan, in the Marquette region, Lake Superior, to enrich the leaner specular ores. This consisted of crushers, Cornish rolls and rotary-jigs. The results ohtained weye not satisfactory, and it has been abandoned. Another plan to treat the lean magnetites from a large dump-pile at Republic, Michigan, by means of pulverizers and water-jigs also

Jan 1, 1889

By E. B. Ekren, F. C. Frischknecht

Recently released results of surveys employing the slingram and turam methods show the applicability of electrornagnetics in mapping new areas containing both oxidized and unoxidized iron in the Lake Superior region.

Jan 10, 1961

SECTION I Page Page Report of Nominating Committee. v Employment li Proceedings of St. Louis meeting. , vi Local Section News.: liv Engineering Foundation, Report Affiliated Student Societies lvi of Secretary xxxviii Forthcoming Meetings lvii Engineering Council xlii. Library lviii Suggested College Course on the Membership lxiii Human Side of Engineering... xlii Biographical Notices: Engineering Societies Club of Alexander Bryden. By C. L. Hawaii xlv Bryden lxxxiii Members in Military Service .... xlv E. F. R o e b e r . B y J. W. Meeting of Board of Directors...' xlvii Richards lxxxv 1918 Dues xlviii Institute Committees lxxxvi Transactions for 1917 xlviii Officers and Directors xciv Personal xlix

Jan 12, 1917

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period Apr. 10 to May 10, 1915: William W. Elmer, Tuttletown, Cal. R. R. Freeman, Jr., Wollaston, Mass. Lawrence Addicks, Douglas, Ariz. Francis R. Pyne, Elizabeth, N. J. W. F. Durand, Stanford Univ., Cal. George B. Pickett, Ophir, Colo. S. P. Cooper, New York, N. Y. R. V. Norris has been elected President of the Columbia School of Mines Alumni Association. Robert C. Sticht has been elected President of the Australian Insti¬tute of Mining Engineers.

Jan 6, 1915

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the first half of March: James C. H. Ferguson, San Francisco, Cal. Capt. A. F. Lucas, Washington, D.C. Henry Adams, Stamford, Conn. Dexter P. Cooper, New York, N. Y. H. A. Wheeler, St. Louis, Mo. L. D. Moore, Chatham, N. J. John M. Sherrerd, Easton, Pa. Hennen Jennings, Washington, D. C. R. T. White, formerly General Manager of the Braden Copper Co., Chile, is to take charge of a copper company in Caucasus, South Russia.

Jan 4, 1914

By John V. Beall

Ten years ago, upon coming home to New York, we had money in the bank, a portfolio of stocks, a rent- controlled apartment overlooking the Hudson and we didn't own an automobile. This was bliss! The just reward of industry and careful management of the fruits of our labor in the mines overseas. Although we kept up a delaying action, the family was pushing hard for a house in the suburbs. We were able to find something wrong with every house that came up but, finally, in a weak moment made the unlikely compromise of putting ten dollars down on a piece of property in Westchester County.

Jan 1, 1971

By Stuart H. Ingram

DEFINITION THE term lightweight aggregate implies material which may be substituted for the usual rock, sand and gravel commonly used as the major part of concrete, but distinguished by being much lighter in weight. BACKGROUND The art of making and using concrete is old and well developed. Research and experience have pretty well determined the qualities necessary in its constituents, and time has tested theories and applications. Elaborate specifications and tests have been devised and generally adopted governing all phases of concrete work, from selection of material, through engineering design and down to mixing and placing. Standard practices have become routine to executives and laborers, and operations have been simplified and costs lowered. Though many lightweight aggregates meet the basic specifications necessary for usefulness, their physical qualities are so different that they frequently will not pass standard tests, and some of them cannot be mixed and placed with the usual formulas for water and slump. As a rule their use produces a concrete with a lower modulus of elasticity which requires design change, and being produced in much smaller quantities than ordinary aggregate, production costs are higher. This latter works in a vicious circle to restrict their use and maintain prices that are not competitive, except as against each other. INCREASED DEMAND In spite of such handicaps consumption has grown steadily for the past two decades and is apparently growing even faster today. It is evident that lightweight concrete must have better qualities, and be sufficiently better to overcome the higher cost and the other difficulties and disadvantages pertinent to the use of a new and different material in an old industry. Hence the study of its main ingredient should be of interest to all engineers. Our group has a double interest in the subject since most of the materials which have been used as sources of lightweight aggregate are either mined, or are by-products of mining operations. We are directly interested in their production as well as their use, and since available supplies of materials suitable are limited, the increasing use, and rising demand, make the discovery of new sources, or the development of processes to adapt other natural materials to this use, a promising field; and one in which our profession should take an active part. RECENT DEVELOPMENT Descriptions of ancient work contain references to the use of spalls of tuffs or pumice in concrete masonry, but it is only since the nineteen twenties that serious attempts have been made to produce and market lightweight aggregates. A period of rapid advance in theory and practice in cements, mortars and con-

Jan 1, 1947

By A. J. Erickson, W. J. Garmoe

In mid-1970, Park City Ventures, a Utah partnership of Asarco and the Anaconda Company, initiated a six-phase exploration and development program in the Park City District, Utah. Geologic studies had delineated a number of exploration targets in several areas of the district. Discovery of ore in any of the target areas and continued favorable downdip development below then productive ore bodies would allow for reserve expansion and mill construction. The targets were: replacement mineralization in the Mississippian Humbug formation below productive ore bodies on the east flank of the Park City anticline; replacement mineralization in the Humbug formation in an unexplored fault block in the footwall of the Hawkeye structure on the east flank of the anticline; vein and replacement mineralization along the Silver Fissure; potentially higher grade replacement mineralization in the Humbug formation in a theorized structural block on the west flank of the anticline beneath the Ontario vein; replacement mineralization in the Permian Park City formation in the West End shaft area of the Silver King mine; vein mineralization along the Back vein in the Judge mine. In 1971 the Judge and Silver King Projects were suspended, due to a 30% cutback in the exploration budget. In spite of the cutback additional reserves were developed below the Humbug East Flank ore bodies; a major zone of ore grade mineralization was discovered along the Silver Fissure, five new ore bodies were found in the Humbug and Doughnut formations on the west flank of the anticline beneath the Ontario vein. First concentrates were shipped from a new mill in May 1975.

Jan 1, 1979

By R. G. Bowman

LEAD is a dull and sober metal, and in times of economic stress it en- joys, or at least occupies, a position which partakes somewhat of its physical lethargy and stability. The past ten years have witnessed in this country a decline in the production of lead, and a shrinkage of ore reserves, following closely the general economic situation. Metal prices have not justified exploration and development of new sources. Momentary rallies in industry have brought no response from lead.

Jan 1, 1940