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WHEN geologists began probing the grayish rock mass, natives of Adams County, Pa., called soapstone, they were paid scant attention. However, the soapstone, at first misidentified as pyrophyllite, was in reality sericite schist, a hydrous aluminum silicate whose chemical analysis resembles pyrophyllite, except that it has a slightly higher iron and potash content. In addition to its grayish color, sericite schist is foliated and has a greasy feeling much like that of talc.

Jan 10, 1953

By M. B. Ramachandra Rao

THE occurrence of copper ores at Garimenapenta, 14° 59 min 30 sec N Lat., 79° 33 min 10 sec E Long., in Nellore district, Madras State, India, has been examined and investigated on numerous occasions during the past two centuries.1 No tangible orebody was ever located as a result of all the ex-

Jan 4, 1953

By Ernest M. Spokes, Martin A. Thieme

A simulation model developed to analyze scraper-pusher utilization in open pit mining systems is described. The mining simulator discussed was developed as a tool to aid management in evaluating alternative open pit haulage schemes and to reduce the risk involved in the selection of equipment.

Jan 1, 1973

By Ernest R. Dickie

IN 1945 the Bagdad Copper Corp. decided to change from block caving to open-pit mining. By early 1948 the conversion was completed and production was increased from 1500 tons per day to 4000 tons per day. Open-pit mining costs decreased approximately 40 pet from the cost of producing ore by the underground method. At present one P & H model 1400 all-electric 4 1/2-yd shovel and one P & H model 1055 Diesel 3-yd shovel are used continuously for stripping. One 21/2yd North- west shovel handles the ore. Delivery of a new P & H 1055 electric shovel for stripping is expected this month. Blasthole drilling is performed with two Bucyrus model 22 and two Bucyrus model 27 churn drills.

Jan 9, 1951

By L. J. Boucher

The beneficiation process at Northampton is described and reasons are given for installing a flotation plant. The economics of running the plant, the difficulties of operation, and subsequent remedial action are discussed.

Jan 3, 1953

The Pueblo plant receives its principal supply of iron ore from the Sunrise mine, located in Platte County, Wyo., and Iron Mountain, southwest of Cedar City, Utah. Limestone from Monarch quarry located on the continental divide above Salida, Colo., is shipped into Pueblo to be used as a flux. Of importance to the successful operation of the blast furnace plant is the ore preparation unit at Pueblo. Due to the geologic structure of both the Utah and Wyoming deposits, the ores, both high in grade, are quite variable in chemical and physical nature.

Jan 11, 1953

By Henry Rogatz

During the year 1937, there were 663 oil wells drilled in the Texas Panhandle, making a daily initial production of 322,332 bb1.—that is, 191 more oil wells drilled than in the previous year, with an increase in the total daily initial production of 66,283 bbl. The total daily potential of the field as determined by the Texas Railroad Commission in its Schedule of Dec. 17, 1937, was 1,039,982 bbl., or an increase of 205,094 bbl. over the previous year. On Dec. 17, 1937, the daily allowable of 68,578 bbl. was assigned to the entire field. The total amount

Jan 1, 1938

By Clement K. Chase

The ammonia leach for copper recovery is discussed from historical and current practice standpoints. The chemistry of the system is presented together with Eh-pH and copper-ammonia solubility curves. A list of metals forming ammine complexes is presented. The advantages and disadvantages of the ammonia leach as applied to copper recovery in conjuction with modern liquid ion exchange techniques are compared.

Jan 1, 1980

By William B. Plank

PRESENT enrollment of 182,361 students in the engineering schools of the United States and Canada represents an increase of 6.6 pct over the enrollment in these schools in 1951-52. Thus is brought to a halt the steady decrease in engineering enrollment that began with the close of the 1947-48 academic year, five years ago. The mineral engineering student picture is similarly encouraging. In the United States schools, 9453 students are preparing themselves for positions in the Mineral Industry. This is an increase of 8.3 pct over last year as compared with an increase of 6.6 pct in the total United States engineering enrollment. The rate of recovery for the mineral engineering group is thus more rapid than for the engineers as a whole.

Jan 4, 1953

Recognizing the fact that the problems of the committee named by the Board to prepare the "official ticket" for officers and Directors of the Institute are various and difficult; and desiring to assist this committee by setting forth some of the principles that should guide the committee and some of the qualifications that should be required of candidates, the following instructions are formulated and the Secretary is directed to publish them in MINING AND METALLURGY concurrently with the publication of the names of each newly appointed Nominating Committee and to send a copy to each member of the Committee.

Jan 1, 1946

By W. Randolph Van Lewis

In determilling the relative rate and in fi~lding the point where different inlpurities containecl in copper-matte are eliminated during the process of a converter-blow, the follo~ving results were obtainecl : A converter was selected which was starting on its sccolld charge. The first charge after lining had finished its copper " hot," and conseqaently no copper was adhering to the sides of the lining. All the copper and granulated slag from the previous charpc mcrc dumped, thus removing ally possibility of " salting " the matte to be tested. The coliverter worked fast and well during the entire test. Periods of ten minutes were selected. The converter mas brought from the stack to secure each sanlple of matte to be

Jan 1, 1904

By John V. Beall

Our moment of truth is in the offing. When the SME Directory is published in this July issue of [8:] we will know how good or how bad our system is for this computerized Directory. At this writing we have not seen the printout. The SME Directory is designed for maximum utility by the membership but this, of necessity, makes the job complicated. In the alphabetical section, names are listed last name first, followed by codes indicating the class of membership, year of election and divisional interests of each Member. This information is followed by job title, company division, company name and address complete with zip code, or simply by the mailing address of the Member in cases where he either has no company or has not supplied the company information.

Jan 1, 1971

By Ralph S. Siegrist

For the past 30 years the construction industry has used steel supports in rock and soft ground to expedite driving tunnels under many difficult conditions. The industry has had a definite advantage in that it bids its work in accordance with the type of job to be encountered. The mining industry has had to keep its progress in line with the economics imposed by the price of the commodity it mines. Even so the mining industry, particularly metal mining, has been using steel support. Timber was universally used because of availability and cheapness, but as timber became scarce and labor more expensive-it takes more time to erect timber support-steel gradually replaced timber.

Aug 1, 1956

By J. H. Wernick

IN a study of the rate of decomposition of ½ -in. cubes of limestone, dolomitic limestone, and dolomite in a sweeping nitrogen atmosphere, Joseph, Beatty, and Bitsianesl found that the zone of calcination advanced at substantially a constant rate at a given temperature. The purpose of this paper is to show that their data indicate at least two processes occurring when the above carbonates decompose. It is suggested that there are two processes occurring temperature range and the other the limiting process over another temperature range. The data of Joseph and co-workers have been extended by use of the Arrhenius equation, Eq. 1, a relation beween the velocity constant k of a reaction and the absolute temperature T.

Jan 7, 1954

By George A. Lamb

Forecasters, in estimating long-term energy requirements and supplies, have predicted a bright outlook for coal. Some predictions have annual coal output reaching 800 million tons by 1980, almost twice the average of the last five years. These projections assume that ultimate consumer energy products will be supplied adequately not only in volume but also by kind and type. The consumer energy schedule shifts continually as it reflects the changing demands for numerous uses. Its appearance, expressed generally in proportions of solids, liquids, gases and electricity, is quite different today from what it was in 1940. It may change even more by 1980. Thus, the shares that coal and the other energy sources will have In total supply will depend upon how well each source can be processed into products that will be accepted by consumers.

Jan 7, 1963

By A. D. Bryant

APPROXIMATELY 2 1/2 million tons of silica sand and ground silica with a value of $7.25 million is produced annually from the Ottawa, Illinois, district. These silica products come from the well known St. Peter sandstone formation which covers part of the Mississippi Basin extending from St. Paul on the north to the central part of Arkansas on the south and from Muncie, Ind., on the east to Kansas City on the west. Practically the whole state of Illinois is underlain by this formation except where removed by erosion. Sand produced from the St. Peter sandstone in the Ottawa district is noted for its purity, uniformity, and quality. In addition to various screened grades for industry about 10 pct of the total production of the Ottawa district is ground into silica flour for use in glass, abrasives, enamel, porcelain, tile, for foundry and filter sand, and other uses.

Jan 3, 1953

By F. S. McNicholas

UNTIL the fundamentals of the physical behavior of rocks are completely understood, progress in block caving must proceed upon a cut and try basis. Criteria of rock failure are many and varied. If a rock mass behaved as a homogeneous isotropic solid, the problem would be greatly simplified. In practice we are never dealing with isotropic or homogeneous rock but with one that has been acted upon by geologic processes and which has pre-existing planes of failure. Under these complex conditions we do not find agreement. Actually there is little agreement between elasticians and physicists as to manner of failure in an isotropic homogeneous solid, although much progress has been made in the study of rock failure in recent years.

Jan 11, 1950

By Whitmell J. Smithwick, Charles E. Dandois

The first operating unit of the ring or annular shaft kiln as developed by Mr. Karl Beckenbach of West Germany was rated 185 tpd and was installed in 1962. Today, there are approximately 84 units in operation in Western Europe and Japan. Twenty-one additional units are under construction or on order. Sizes range from approximately 100-330 tpd, however, units of over 500 tons are in the design stage. The ring shaft kiln is a single vertical cylinder to which are attached the required service platforms, combustion chambers, injectors and distribution piping (Fig. 1). Auxiliaries such as recuperator, exhaust fan and dust collector are mounted on the appropriate service platform. The charging pan, feed conveyor, etc., are mounted at the kiln top and at the bottom of the kiln is the silo with a vibrator type discharger. Mounted separately is the required blower for injector air and fan for internal cooling.

Jan 4, 1973

By Benny Langston, Frank M. Jr. Stephens

IN recent years much attention has been given to recovery, treatment, and disposal of dusts discharged into the atmosphere from operations of industry. Considerable data has been accumulated on both operational1-4 and design5,6 of dust-collector equipment for commercial installations. On the other hand, there is almost no published data on design and construction of small-scale equipment to handle dust problems that arise in the ore-dressing laboratory. Dust-collection equipment such as multiclones, single-cyclones, scrubbers, chemical and mechanical filters, settling chambers, and electrostatic separators has proved its efficiency for collecting dust in industry. In the laboratory, however, the engineer is faced with the problem of collecting small quantities of dust, inexpensively, without diverting the major effort from the metallurgical problem to the problem of collecting dust produced by the process.

Jan 8, 1954

By B. C. Morrison

Because of U.S. Forest Service regulations and the consequent cost of leaving several diamond drill holes open at the same time, it was necessary to develop an electrical method that could be used in one hole at a time to extend known mineralization. This was achieved by balancing the surface current electrodes so that the two potential electrodes in the hole being surveyed were in the same equipotential surface. This condition eliminated stratigraphic response but enhanced any asymmetry due to ore between the hole and either current electrode. This method was successfully used in mineralized holes at West Fork, Reynolds County, Mo., to show the direction in which to extend the drilling into areas of better mineralization.

Jan 1, 1972