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By K. BRUCE DAVIDSON

-The North Central Texas area includes the following counties in Railroad Commission of Texas District 7-B: Brown, Callahan, Coleman, Comanche, Coryell, Eastland, Erath, Fisher, Hamilton, Haskell, Hood, Jones, Lampasas, Mills, Nolan, Palo Pinto, Parker, S

Jan 1, 1946

By R. A. Breitrick, J. N. Swinderman, J. J. Cooper, H. L. Bauer Jr.

The Robinson Mining District, near Ely, Nev., is one of the major porphyry copper districts in the world. Within the district is an eight mile long east-trending zone of altered porphyry, metamorphosed sedimentary rocks, and sulphide mineralization surrounded by Paleozoic limestone, dolomite, shale and sandstone, Tertiary volcanics, and Quaternary alluvium. Six major disseminated ore deposits have been exploited in this zone. About 20% of the district production has come from disseminated ore in metamorphosed sedimentary rocks found adjacent to altered quartz-monzonite porphyry. The following brief statements summarize some of the relations between porphyry alteration, metamor-phism, and mineralization: 1) Disseminated copper ore does not occur in unaltered porphyry or in m-metamorphosed sedimentary rocks. 2) Sedimentary rocks have been only weakly metamorphosed where intruded by unaltered porphyry. 3) Intensely metamorphosed sedimentary rocks are found only adjacent to altered porphyry. 4) Many hydrothermal minerals are common to both altered porphyry and adjacent metamorphosed sediments. 5) Disseminated ore is found in altered porphyry and adjacent metamorphosed sedimentary rocks. 6) In general, there is a direct correlation between grade of ore in porphyry and copper content in the adjacent rocks. 7) Chemical changes in the altered porphyry and metamorphosed rocks appear to be related. The foregoing relations support a hypothesis that the porphyry alteration, the metamorphism of the sedimentary rocks, and the ore deposition were all part of a continuous hydrothermal process which probably closely attended the porphyry intrusion. The Robinson Mining District, most often referred to as the Ruth or Ely District, is located in eastern Nev. and is one of the major porphyry copper districts of the world. Production from 1908 through 1962 was nearly 250 million tons of ore averaging a little over one percent copper with a total metal value of nearly one billion dollars. The ore has been produced from six major disseminated-type deposits with the Liberty Pit deposit accounting for 70% of the total district production. Less than one million tons of base metal and gold ores have been produced from the replacement-type deposits of the district. Approximately 20% of the district production has come from underground mining operations; the pit ore has been mined with shovels and removed by train haulage, truck-train haulage combinations, truck haulage, and presently by a combination truck-skip system. Many of the ore deposits formerly worked by underground methods have been and are being exploited by open pit methods. (See Fig. I.) Two co.'s have accounted for virtually the entire production from the district. In 1958 Kennecott Copper Corp. acquired the district assets of Consolidated Coppermines Corp. and is now the sole ore producer in the district. Present operations are confined to the Liberty Pit where 22,500 tons of ore averaging a little less than 0.8% copper is mined per day. Cutoff grade is 0.4% copper, and the stripping ratio is three to one. The ore is hauled by rail 23 miles to the McGill Reduction Plant where it is concentrated to about 20% copper. Molybdenite is recovered as a by-product in the mill. The copper concentrates are smelted in McGill, and the blister copper is shipped for refining to Balt. where gold, silver, platinum and palladium are recovered. The Robinson Mining District has been well known as a porphyry copper district for the past fifty years, but many geologists are unaware of the fact that a large portion of the production has come from disseminated ore found in metamorphosed sedimentary rocks. The scope of this paper describes the occurrences of disseminated ore in the various metamorphosed sedimentary rocks, and presents evidence for the hypothesis that these ores are genetically, spacially, and coevally related to the disseminated ore in the porphyry rocks. Publication of this paper was granted by the management of Kennecott Copper Corp. A. H. James suggested and encouraged the writing of the manuscript. Special mineralogical and spectrographic analyses were performed by the Kennecott Research Center. The deposits of the district have been studied by many geologists since the turn of the century, and

Jan 1, 1964

A GREAT and incomparable speculation is whether the discovery of A compounding the powder used for guns came to its first inventor from the demons or by chance. With this invention he certainly far surpassed all men of every age from the creation of the world up to that day when it was announced by him-men so very learned, indeed like angels and of divine intellect, powerful in every knowledge and power. These had not only revived-arts and sciences and discovered new ones with their intellects, but they had information about all natural

Jan 1, 1942

H. H. Kellogg (Columbia University)—The accurate measurements of the equilibrium gas ratios for the reaction: Pb(1) + H2S = PbS(c) + H2 [I] reported in this paper are a distinct contribution to the literature, and the authors are to be congratulated. I wish to comment, however, on the correlation of the data which is presented. The authors show a straight line correlation of log H2S/H2 vs 1/T, Fig. 1, and are satisfied with this for calculation of ?Fo even when extrapolated to low temperature (427 °C). Heat capacity data for the constituents of this reaction are available (at least to 900°K), however, and ACP for reaction [I] is finite and positive in the temperature range studied. Simplification of the heat capacity equations yields: ?CP= 2.71 + 1.65 x 10-3T (298°-900°K) This positive value of ?CP should result in a small but noticeable curvature of a plot of log K vs 1/T. That the experimental data fail to show such a curvature may be traced to another oversimplification of the author's treatment of their data. They assume that the activity of liquid lead is unity for all temperatures, so that

Jan 1, 1961

By Elton A. Youngberg

The Holden mine operated by the Chelan Division of the Howe Sound Co. is on the east slope of the Cascade Range in north central Washington on the south slope of Railroad Creek valley at an elevation of 3500 ft. The mine may be reached by a 40 mile boat trip from the town of Chelan which is at the southern tip of Lake Chelan, to Lucerne at the mouth of Railroad Creek and an 11. mile bus ride up Railroad Creek to Holden. A11 freight and concentrate is moved over this route to Chelan Falls on the Columbia River which is on the railroad four miles below the town of Chelan. The mine is now producing 2000 tons of gold, copper, and zinc ore per day which is treated in the Holden mill. Gold-copper and zinc concentrates are made, the first of which is shipped to Tacoma, Wash., and the latter to Kellogg, Idaho, for smelting. Ore is broken by long-hole blasting using the Noranda system which has been modified to meet local conditions. Until recently, blastholes have been drilled by diamond drills. Now a partial substitution of percussion drill holes, drilled with tungsten carbide insert bits, is being made. Geology The ore body occurs as a replacement deposit in a highly metamorphosed series of sedimentary rocks, mainly gneiss and schists, in a shear zone several hundred feet in width and of undetermined length. Commercial ore has been found in mineable widths of 25 to 100 ft for approximately 2500 ft along its strike. The commercial minerals are chalcopyrite, sphalerite, and gold. During the period of mineralization considerable silicifica-tion took place giving the ore an abrasive drilling characteristic. Following the period of mineralization, numerous dikes were introduced into the ore body. The earlier ones were of granite composition having a width of a few inches up to 80 ft. These were followed by much younger, fine grained basic dikes which usually do not exceed 2 ft in width. Development of Percussion Blasthole Drilling Equipment Test work with the 1½-in. tungsten carbide bit was carried on in development headings for several months early in 1947. The short life of the bits, because of gauge loss caused by the abrasive nature of the rock, prevented its adoption for this use. However fast drilling speed and ability to drill a long uniform hole suggested its use for drilling blastholes in competition with diamond drills as diamond costs were steadily increasing and exper-ienced drillers were difficult to obtain. The 1½-in. bit was the largest available at the time initial test work was started with sectional steel. The 1½-in. hole limited the diameter of the steel thread and coupling which could be used. Type F couplings were first used but because of the small thread section excessive breakage of the steel was experienced. Type H couplings were tried next. In order to use this coupling which is 15/8 in. in outside diameter, it was reduced to 1 3/8 in. giving 1/8 in. clearance between the coupling and the hole. Rod breakage at the thread was substantially reduced but some coupling breakage was experienced, however the overall performance was considered satisfactory (see Fig 1 for illustration of coupling and thread). Early test work with the 1½ in. bit indicated machines of piston diameters larger than 255 in. would cause inserts to loosen or break. It was found however that the additional weight of the sectional steel cushioned the blow enough to prevent bit failures when 3-in. Leyners were used. Rods used with the 1½-in. bits were 7/8 in. q. o. for sectional steel and 1 in. q. o. for all chuck pieces. In May 1948, 2-in. tungsten carbide bits became available and test work was immediately started. The 2-in. hole approximated the AX (1 15/16 in.) diamond drill hole which was being used exclusively for blastholes and permitted their substitution for diamond drill holes in a ring without alteration of pattern, burden, or explosives. The 2-in. bit also gave room in the hole for larger couplings and permitted the use of heavier rods and 3½-in. machines, increasing the

Jan 1, 1950

The Commissioner of Education has issued a call for a public conference on business training for engineers and engineering training for students of business. This conference, national in scope and character fully representative of all interests, will be held in Washington, D. C. on June 23 and 24. Educational institutions, commercial organizations, and educational and engineering societies will be given an opportunity to state their views. Engineers, educators and business men will be invited to discuss the following major topics: Business Training for the Engineer; Engineering Training for Commercial Enterprises; Significance of the. War Experience for Engineering Education; Training of the Engineer for Foreign Projects. This conference has been called on behalf of the Conference Committee on Commercial Engineering. This Committee is composed of administrative professors in engineering and commerce from several of the large educational institutions and representatives from the American Institute of Mining and Metallurgical Engineers, Society for the Promotion of Engineering Education, The American Society of Civil Engineers, American Institute of Electrical Engineers, American Society .of Mechanical Engineers, and a committee f fifteen on Educational Preparation for Foreign Service.

Jan 6, 1919

By D. L. Murphy

As the world's demand for iron ore increases and available sources are depleted, increasing attention will be centered on deposits in the Quebec and Labrador portions of the Labrador Trough. Improvements in the beneficiation of low grade iron ore stimulate exploration for deposits amenable to concentration. This study is centered on the Mt. Wright-Lake Carheil area, lying between Wabush Lake and Mt. Reed in Quebec. Described in detail are the general lithology, structural and economic geology, and mineralogy of the iron-formation. The iron ore province of Quebec and Baffin Island extends from the southern shore of Baffin Island southeasterly through the Labrador Trough to Matonipi Lake, approximately 185 miles northwest of Seven Islands. (See Fig. 1.) Future geologic field studies will very likely extend the limits of the province to include the ferruginous and associated rocks of the Lake Mistassini area. At present, only the deposits near Knob Lake and Lake Jeannine (Mt. Reed) have been brought into production although in the near future several other properties including those at Wabush Lake will commence operations. Within the next decade or so, as the world's demand for iron ore increases and available sources are depleted, this region will undoubtedly become a major mining district. Initial reports of iron-rich rocks in Labrador date back to the investigations undertaken by A. P. Low near the turn of the century. During the ensuing years the country was prospected chiefly for precious and nonferrous base metals because of its inaccessibility and the low tenor of the iron ore. In 1945 an evaluation of the direct shipping ores near Knob Lake indicated that sufficient reserves were present to justify the enormous capital expenditure required to bring the deposits into production. Initial open-pit mining began in 1954 following the construction of a townsite, a 360-mile long railway to Seven Islands, and an elaborate loading dock. Recent improvements in the beneficiation of low-grade iron ore have stimulated widespread exploration for deposits amenable to concentration, particularly along the southwest extension of the Trough. The Mt. Wright-Lake Carheil area, bounded by longitudes 66O45' and 67 30' west and latitudes 52 30' and 52 45' north, is a nearly rectangular tract of slightly less than 500 sq miles. It is in Saguenay County, 174 miles north-northwest of Seven Islands (see Fig. 1). Except for the periods of the spring breakup and the fall freeze up, the area is readily accessible by air.

Jan 1, 1962

By Horace Mann

A FEW years ago, it was generally thought that from 15 to 18 per, cent. of zinc oxide was the upper limit of a workable lead blast-furnace slag. With slags above this zinc-oxide content, the furnaces gave so much trouble because of hearth, wall, and crucible accretions that the campaign was very short. The time lost in cleaning out the frozen furnaces, for it was seldom possible to blow them out, and blowing in was so great that it was considered uneconomical to attempt the running of high-zinc slags, even if this were metallurgically possible. It is true that there are, references to one or two slags much higher in zinc than the foregoing,1 but the average smelterman regarded these, as freaks and not to be considered for regular furnace work. One or two plants, notably the plant of the United States Smelting Co, at Canyon City, Colo., ran charges, higher in zinc. At this plant, the zinc-oxide content of the charge was frequently 20 per cent. and higher but the slags from these furnace's seldom ran over 10 to 12 per. cent. zinc oxide. The furnaces were run with a large volume of air under a relatively low pressure, a low smelting column, and a very hot top; as a result, a large amount of zinc was volatilized. Even with the low smelting column and hot top, accretions caused much trouble and barring, down was a daily occurrence. At the time most of the theories on lead blast-furnace work were promulgated or worked out, it was necessary to run a furnace with a cold top in order to avoid an excessive loss due to fines and fume. At the same time, the smelting conditions had to be such that the lead and silver would be reduced and would enter the bullion. The slag had to be liquid but the charge must not give excessive accretions either in the hearth or on the walls of the furnace. This forced the operators to run the furnaces with a comparatively low blast, which, in turn, caused a small fuel consumption per unit of time with the accompanying result of a low working temperature.

Jan 8, 1925

By Wallace W. Wilson

The Cook Ranch Field produces from a very permeable lens of Cook Sand of lower Permian or upper Pennsylvanian age, occurring at an average depth of 1.300 ft. The field was discovered in 1926, and has been operated with low pressure gas injection since July, 1927, one of the first such projects in Texas. Cumulative recovery to Dec. 31. 1950, was 14,701,131 bbl of crude oil, an average of 1,013 bbl per acre-ft of oil rection. and 72.5 per cent of the oil originally in place. Analysis of the reservoir performance indicates that grav-ity drainage has been an important factor in the producing mechanism. The high permeability and uniformity of the reservoir were extremely Favorable tor this type of operation. INTRODUCTION The Cook Ranch Field is the largest of a number of relatively small, shallow producing areas near .Albany, in Shackelford County, Texas. This field is one of the first to be operated by gas injection in Texas, and probably is the most successful low pressure gas injection project ever attempted. The field is owned entirely by Koeser and Pendleton, Inc., and Continental Oil Co., and has been operated by Roeser and Pendleton, Inc., since it was discovered. This study has been made possible through the cooperation of Roeser and Pendleton, Inc.. in making availahle a remarkably complete set of records covering all phases of their operations. The purpose of this paper is to present a summary of the history of the operations through Dec. 31, 1950, and to analyze some of the factors which appear to be responsible for the success of the project. Information concerning the physical plant and the early gas injection history has been presented in an earlier paper.' RESERVOIR CHARACTERISTICS production in the Cook Ranch Field is from a large lens of Cook Sand. of lower Permian or upper Pennsylvanian age, occurring at an average depth of 1.300 ft. The average dip of the sand body, as shown in Fig. 1. is only about 50 ft per mile to the northwest. The reservoir has an area of 930 acres and contains 15,512 acre-ft of Sand, consisting of about 14.512 acre-ft of produc-tive oil zone. and an estimated 1.000 acre-ft of primary gas-cap. The iso-pachous map (Fig. 2) was prepared from drillers' logs. Recent coring in the field has proven these logs to be quite accurate. The productive limits of the field are defined by shale on all sides but the southwest where a small zone of edgewater was encountered. This water does not appear to have encroached into the reservoir, and water production has been small. A smaller producing area to the south of the Cook Ranch Field also produces from the Cook Sand. but is separated from the reservoir under consideration by a band of shale. The sand consists of well sorted, coarse grained. rounded and subangu-lar quartz fragments. very poorly cemented. The analysis of 46 chip-core samples from two recently completed test wells indicates a range of porosity values between 12.5 and 28.2 per cent. wit11 an arithmetic average of 24.0 per cent. Air permeability values range between 50 and 2,300 md, with an arithmetic average of 1.200 md. The reservoir where cored is a Solid sand body. with no discernible major shale breaks or impermeable streaks. Vertical permeability appears to be of the same magnitude as the horizontal permeability. A core of the Cook Sand was cut ill the smaller field to the south, using lubricating oil as drilling fluid. The connate water content of the sand in this core was found to average about ten per cent, and the porosity and permeability were comparable with the values reported above. No analysis was made of subsurface or recombined hydrocarbon samples,

Jan 1, 1952

Solution mining got back in the news recently when Kalium Chemicals, Ltd., a joint subsidiary of Pittsburgh Plate Glass and Armour & Co. announced its plans to go full speed ahead in mining potash by the solution method in its vast holdings 30 miles west of Regina, Saskatchewan. The company is keeping the technical details of this mining technique under wraps for competitive reasons, but company officials insist that the major difficulties in solution mining of potash have been overcome and that the final product will have definite competitive advantages on the open market. Kalium's holdings in the Regina area total about 500 sq mi. The ore-primarily sylvite mixed with appreciable quantities of halite-occurs in the Prairie Evaporite formation at a depth of 5300 ft. The ore zone averages about 100 ft in thickness. Too deep to be economically mined by conventional underground methods, such as is being done at International Minerals & Chemical Corp.'s Esterhazy mine (depth about 3100 ft), Kalium gambled that it could develop a successful method of solution mining even though earlier attempts in Germany, the U.S., and Canada had failed.

Jan 6, 1964

By J. C. Bayles

It is seldom the privilege of one who contributes to the Transactions of a technical society, to describe a new industry in which, by processes employed for the first time, are attained results of conspicuous value. There are but few such patches of virgin soil worth the tilling, within the area circumscribed by the industries which have experienced a regular and uniform development. New and startling methods in production are often announced as about to be introduced; but, as a rule, they take their place among the " large desires with most uncertain issues," or give new significance to the historic words of an eminent statesman concerning " the bright beginnings and the bitter end of a halcyon and vociferous proceeding." In this paper I shall have the pleasure of briefly describing a new industry which has been established without announcement or proclamation — the manufacture of serviceable pressure pipes of great strength, from strips of steel or iron wound spirally, heated only along the overlapping edges, welded by hammering and finished into tubes of uniform diameter, and of such length as mag be found convenient in handling and transportation. As such tubes are now manufactured on a considerable scale, in a range of sizes which will soon include everything between 4 inches and 30 inches, and as much larger as may be needed, both process and product are likely to be of interest to engineers in all departments of professional work. The raw material of the industry is the ordinary sheet-iron or steel of commerce, of such lengths and widths as it is convenient to roll. The range of the ganges of the metal which can be employed has riot yet been determined. The lightest metal thus far successfully made into pipe is No. 29 iron, and the heaviest a steel gauging somewhere between 12 and 14. Heavier machines are now building which will bend steel .165 of an inch in thickness, or No. 8 of' the Birmingham gauge. Probably No. 20 or No. 22 will be the lightest used in making commercial pipes; hut the experiment with No. 29 was interesting as showing the readiness with which the flame can be controlled. To get a welding heat with such thin

Jan 1, 1888

By James H. Boettcher, W. Durand Eppler

INTRODUCTION In the second quarter of 1979, Rapid Mining Co., Inc. ("Rapid") inquired whether Crocker National Bank ("CNB") would provide $4 million in term loan financing to help ("Dry Creek") acquire the outstanding shares of the Dry Creek Coal Company ("Dry Creek") in West Virginia. Prior to approaching CNB, Rapid had sought financing with the assistance of a financial advisor from a number of commercial banks without success. A summary of the initial terms requested by Rapid is shown in Table 1 compared with the actual terms on which the transaction closed. It is not difficult to note that the two sets of terms differ significantly. This is often the case when financing requests based on the expectations and vision of a mine developer are juxtaposed with more pragmatic requirements of a commercial bank. The "art" and fund of structuring financing plans for mining ventures (highly leveraged acquisitions or grass roots) comes in working with mine developers to arrive at a final financial structure that meets their objectives and constraints as well as those of the bank or other financial institutions providing much of the financing. Beginning with the terms requested by Rapid and ending with the terms that closed the transaction, this article briefly describes the process we went through with Rapid Mining. The Seller and Buyer The Dry Creek Coal Company was established in 1961, after its owner acquired the coal leases from Republic Steel. Republic has mined the primary coal seam from 1948-1961. Dry Creek was owned as a subchapter S corporation (i.e., for federal income tax purposes, income is taxed at the shareholder level) and had been run on a low key basis. Since the company had virtually no debt and limited cash needs, the owner produced primarily when rail cars were available and income was required. Output was therefore erratic as is shown in the top of Table II, but the result was a profitable little company with an attractive free cash position. Because the owner wished to retire and enjoy his wealth in a more readily spendable form, he had put the mine, with stated recoverable reserves of approximately 13 million tons, up for sale. In contrast, Rapid Coal's investors consisted of a number of investors of disparate financial situations. They had agreed upon a primary objective of income maximization and planned an annual production rate of 120,000 TPA which they and the current owner believed realizable. The Formulation of a Financing Structure Figure 1 presents a simplified overview of the sequence of steps taken in the financing process which lasted approximately three months from start to finish. Since banks see many requests for funding and considerble time is required to follow up on each, an important step was determining, after a brief review of the materials provided to us, whether the basic "eonomic entity" was viable. In this case, the size and quality of the reserves, the inherent operating cost characteristics, the sales arrangements, the management/labor situation and Rapid's principles all appeared to be sound enough to warrant investing the time necessary to do a thorough analysis of the project. Once this decision was made, the evaluation and analytic process shown in Figure 2 was initiated. The first and most fundamental concern of any banker is whether the loan will be paid back as scheduled from the cash flow generated by the project. The amount of debt relative to the owner's equity is of course crucial in such a determination. Before the debt/equity issue was addressed, however, a number of more qualitative factors had to be studied and if

Jan 1, 1985

By Mario L. Villa

Argentina's oil production continues in its upward trend. The year 1940 closed with an important increase over 1939; that is, 1,996,371 bbl., or 10.72 per cent. The Government oil fields (Y.P.F.) are responsible for these results, as their total output was 12,474,655 bbl., which compared with the 10,222, 533 bbl. produced in 1939 represent an increase of 2,252,122 bbl., or 22.03 per cent. Fields operated by private companies yielded 8,134,882 bbl., against 8,390,633 bbl. in 1939, a decrease of 255,751 bbl. (3.04 per cent). To the total of 20,609,538 bbl. produced in 1940 in Argentina, the Comodoro Rivadavia field contributed 14,976,222 bbl.; Plaza Huincul, 1,275,814 bbl.; the Province of Salta, 1,845,1977 bbl. and the Province of Mendoza, 2,51I,475 bbl. Table 3 compares the output of companies working in Comodoro Rivadavia. The total increase of 186,819 bbl. (1.26 per cent) registered in the Comodoro Kivadavia area is due only to an intensification of development programs in the known

Jan 1, 1941

By Mario L. Villa

Argentina's oil production continues in its upward trend. The year 1940 closed with an important increase over 1939; that is, 1,996,371 bbl., or 10.72 per cent. The Government oil fields (Y.P.F.) are responsible for these results, as their total output was 12,474,655 bbl., which compared with the 10,222, 533 bbl. produced in 1939 represent an increase of 2,252,122 bbl., or 22.03 per cent. Fields operated by private companies yielded 8,134,882 bbl., against 8,390,633 bbl. in 1939, a decrease of 255,751 bbl. (3.04 per cent). To the total of 20,609,538 bbl. produced in 1940 in Argentina, the Comodoro Rivadavia field contributed 14,976,222 bbl.; Plaza Huincul, 1,275,814 bbl.; the Province of Salta, 1,845,1977 bbl. and the Province of Mendoza, 2,51I,475 bbl. Table 3 compares the output of companies working in Comodoro Rivadavia. The total increase of 186,819 bbl. (1.26 per cent) registered in the Comodoro Kivadavia area is due only to an intensification of development programs in the known

Jan 1, 1941

By Samuel Lasky

THE writer has been interested in determining the mineralogic dis-tribution of silver in the base-metal ore of the Ground Hog mine of the Asarco Mining Co. in the Central mining district of New Mexico.1 This ore consists of a varitextured mixture of sphalerite, chalcopyrite, galena and pyrite in a quartz gangue. The average ore contains 14 per, cent of zinc, 9.5 per cent of lead, 5 per cent of copper, and 10 oz. of silver per ton. Generally it is accepted that the silver in ores of this type, in which no definite silver minerals can be recognized, is contained in the base-metal minerals. Published assays of pure mineral specimens from many dis-tricts show that each of the base-metal minerals contributes in some degree to the total silver content of the ores, and to determine the pro-portionate amount contributed by each mineral in any specific ore it has been the practice to assay selected specimens of each mineral, the purity of which has been determined microscopically. There being no such assays available for the Ground Hog ore, and it being impract cable to have enough of them made to give average results, the writer resorted to a mathematical attack upon composite assays of large quantities of ore and concentrates. Surprising results were obtained, and it is the threefold purpose of this paper to present these results, to describe the mathe-matical method used, and to point out the value of using this method even when assays of pure specimens are available.

Jan 1, 1934

THE Institute assembled in Packer Hall of the Lehigh University, the President, Mr. David Thomas, of Catasauqua in the chair. Professor Henry Coppée, President of the Lehigh University, made an address of welcome to the Institute, and placed at its disposal a convenient hall for purposes of meeting. Mr. Thomas tendered his resignation as President of the Institute, as advancing years prevented him from actively participating in its meetings. The Institute declined to accept the resignation, and, on the assurance that active duties would not be expected of him, Mr. Thomas was induced to withdraw it. Invitations were received from Mr. B. C. Webster, President of the Lehigh Zinc Company, to visit the mines and works of the company; from Mr. Charles Brodhead, to visit the Chapman Slate Quarries; and from the Lehigh Coal and Navigation Company, to visit their works at Summit Hill and Mauch Chunk and the Nesquehoning Tunnel. The Council reported the names of persons already elected in the two classes of members and associates. The following resolutions were passed : Resolved, That a committee of three be appointed, who shall take into consideration the printing and publishing of papers originating with the Institute, and that a uniform system as regards size and execution be adopted. The committee appointed consisted of Messrs. R. W. Raymond, E. B. Coxe, and the Secretary. Resolved, That the Council design and prepare a seal for the Institute at the earliest practicable time. Resolved, That a committee of six, with power to add to its numbers, be appointed to examine into the question of the more economical production of iron in this country. The committee appointed consisted of Messrs. G. W. Maynard,

ROBERT WOOLSTON HUNT, who joined the Institute in 1874, served twice as its President, was made Honorary member in 1919, in whose honor the Hunt prize and medal were established, and who, within a month, had received the Washington Award, died at his home in Chicago on July 11, 1923. Robert Woolston Hunt was born Dec. 9, 1838, in Fallsington, Buck County, Pa., His father, Dr. Robert A. Hunt, of Trenton, N. J., graduated from Princeton College in the class of 1824, and later from the Uni-versity of Pennsylvania. His mother was Martha Lancaster Woolston. Mr. Hunt spent several years learning the practical side of iron making in the roll-ing mills of John Burnish & Co. at Pottsville, Pa. Later he took a course in analytical chemistry in the laboratory of Booth, Gar-rett & Blair, upon the completion of which he entered the employ of the Cambria Iron Co. at Johns-town, and for them, on Aug. 1, 1860, established the first laboratory in Amer-ica forming an integral part of an iron or steel organization. In the fall of 1861 he en-tered the United States military service, and was in command of Camp Curtin at Harrisburg, serving as mustering officer for the State of Pennsylvania, with the rank of Captain. In 1864 he assisted in recruiting Lambert's Independent Mounted Company, and was mustered into active ser-vice as a sergeant, having tossed up with a friend who had also participated in recruiting the company, as to which one should receive a Lieutenant's commission. Upon being mustered out of service, Mr. Hunt returned to the employ of the Cambria Iron Co. which sent him to the works at Wyandotte, Mich., where experiments with the new Bessemer process of making steel were being conducted. He was placed in charge of those works in July, 1865, and so continued until May, 1866, when the Cambria company called him back to Johnstown to take charge of their steel business, intending at once to begin the erection of a Bessemer steel plant. The plant, however, was not built for several years, and in the meantime the Cambria company began the rolling of steel rails for the Pennsylvania Railroad, using ingots of Bessemer steel produced by the Pennsylvania Steel Co. at their Steelton works. Mr. Hunt had charge of the steel for these operations; and in August, 1867, the first steel rails made in America on a commercial order were rolled.

Jan 8, 1923

By O. W. Ellis

RECENTLY there has been a considerable revival of interest in the effects of the various elements commonly added to brass for the purpose of increasing its strength. For many years the work of Guillet2? alone gave reliable information in this regard. Even today his determination's of the coefficients of equivalence of the various elements relative to zinc in brass are those universally employed in industry. This is so because these coefficients have stood the test of time-their substantial correctness has been proved in almost universal practice. It is not our intention to discuss here these coefficients or their use. Rather do we wish to emphasize the need for further systematic studies of the mechanical properties of the ternary systems of copper, zinc, and other individual elements. Since Guillet published the results of his first investigations Millington,16 Smalley33 and Thibaud45 have added somewhat to our information. In general they have confirmed the findings of Guillet, which may be stated in the following rather general terms: 1. The addition of aluminum to the 70:30 and 60:40 brasses progressively increases their hardness and strength and reduces their ductility and resistance to shock. 2. The addition of small amounts of iron to a 60:40 brass improves its strength without affecting its ductility. 3. The addition of small amounts of manganese to a 60:40 brass causes a progressive increase in its strength and reduction in its ductility. A considerable amount of information has been amassed in regard to the effect of nickel on brass (9, 22, 41) which it is unnecessary to refer to here, in view of the scope of this paper.

Jan 1, 1929

Our examination was made in accordance with generally accepted auditing standards, and accordingly included such tests of the accounting records and such other auditing procedures as we considered necessary in the circumstances , In our opinion, the accompanying statements present fairly the financial position of the Institute as at December 31, 1951 and the results of its operations for the year ended on that date, in accordance with the method of accounting maintained by the Institute for 1951, which (except for a charge to expense of $12,500 00 in 1951, in which we concur, to provide for increasing the reserve for depreciation to an amount considered appropriate as at December 31, 1951) was consistent with that followed for the preceding year

Jan 1, 1952

By Helmut Thielsch

DURING the last three decades a great many arguments have been presented on the subject of "mosaic" or "block" structures of metals. Apparently because of insufficient evidence, the "block-structure" theories have never been widely understood among the physical metallurgists in this country, and most investigators among the few that have tried to demonstrate the existence of such an inner structure of crystals or grains have failed to recognize also the existence of a lamellar structure. Moreover, little thought has been given to justify the existence of such "lamellar" or "mosaic-block" structures on a theoretical basis. Since properties such as plasticity, ferromagnetism, hardness, diffusion, and others may be explained by structural faults in the lattice network of the crystals, the great importance of a more detailed knowledge of the structure within crystals or grains becomes now evident. Because of the vast extent of the field of submicroscopic structures, it shall be the purpose of this paper only to review the more important of the results obtained by other investigators, especially in Germany, where a great deal of attention has been given to mosaic structure during the last three years. The origin of this mosaic pattern f and effects of cold reduction and recrystallization will be shown in further studies later on. IMPERFECTIONS IN CRYSTALS The many terms used in the literature to denote structural types of crystals are often not clearly defined. To clear up some of the confusion, the meaning of the more important terms will be given here. Ideal, or Perfect Crystals.-Crystals without any structural imperfections are called "ideal crystals," or "perfect crystals," meaning a homogeneous interior structure of atoms, ions or molecules, as the case may be. In other words, at every point in the interior of the crystal exactly the same orientation of the crystallographic axes of the coordinate system would exist. The surface of such a body, if etched with an appropriate etching reagent, would reflect light with perfect uniformity. Crystals of this type are almost nonexistent. Real Crystals.-" Real crystals"' may contain various types of structural defects, which can be classified into: (I) lineage structure, (2) mosaic-block structure, (3) lamellar structure. The inhomogeneities existing in these groups mean that the orientation of the crystallographic axes will not be the same at every point within the interior of a crystal (or grain of a polycrystalline body). Perfect Real Crystals.-The term "perfect real crystals" is generally used to describe crystals with minute structural or thermodynamical inhomogeneities. The former

Jan 1, 1945