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By Karl J. Benecke

Though the first patent on a bucket wheel excavator (BWE) was granted in 1881 in the US, this technology was developed in Germany to the high standards of today. However, this development was only possible in parallel with development of shiftable belt conveyors and boom stackers. The combination of these three types of equipment in the open pits of the Federal Republic of Germany has made lignite the cheapest energy source for power generation, despite the low heating value of German lignite on the order of 8500 kJ/kg (3600 Btu/lb) only. Comparing the costs for fuels used in power generating on the basis of their heating value, the relation between lignite, high quality black coal, and imported crude oil is on the order of 1 to 1.5 to 2.5, hence highly in favour of lignite.

Jan 8, 1979

By Karl J. Benecke

Though the first patent on a bucket wheel excavator (BWE) was granted in 1881 in the US, this technology was developed in Germany to the high standards of today. However, this development was only possible in parallel with development of shiftable belt conveyors and boom stackers. The combination of these three types of equipment in the open pits of the Federal Republic of Germany has made lignite the cheapest energy source for power generation, despite the low heating value of German lignite on the order of 8500 kJ/kg (3600 Btu/lb) only. Comparing the costs for fuels used in power generating on the basis of their heating value, the relation between lignite, high quality black coal, and imported crude oil is on the order of 1 to 1.5 to 2.5, hence highly in favour of lignite. These cost advantages for lignite in Germany are due mainly to the concentration of lignite mining in a few high-output mines. The largest one, Fortuna mine in the Cologne district, produced a total of 45 million tons of lignite in 1976. That equals the annual fuel need of a 5750 MW power plant running 7000 hours per year at full capacity. Altogether 95.2 million bank m3 equal to 200 million tons of overburden had to be removed to accomplish this lignite output. The largest BWE ever built is working in the Fortuna mine [(Fig. 1)]. At a digging height of 51 m above crawler level, the total vertical reach in relation to the face conveyor level is 98 m by means of its conveying bridge and loading unit. The hourly output is 10 400 bank m3. Its weight in operation is 13 000 tons and its wheel diameter 21.6 m, as high as a seven-story building. Major reasons for the development of BWE technology in Germany were: ? Lignite deposits with moderately consolidated, alluvial-type overburden (gravel, sand, loam, marl, clay, etc.) ? Great overall depth of the deposits, ranging far beyond 100 m, requiring a wide opening of the mine, hence not permitting direct overcasting of overburden. ? Multiple-seam deposits of poor-quality coal divided by reject partings, which demand a perfectly selective digging tool for clean separation. In general, these conditions are almost identical to those prevailing in the lignite deposits of Texas and neighbouring states: The type of overburden suitable for BWE digging, the overall deposit depth ranges down to around 100 m, and finally, the multi-seam occurrence with partings between seams, the latter ranging from just 1 m to a few meters in thickness. Technique As the Texas-type lignite deposits come into focus more and more as a possible fuel source in power plants to replace natural gas and crude oil, the following will deal with the BWE technology for mining a typical Texas lignite deposit under the aspect of producing enough fuel for a 500-MW power plant located at the mine mouth.

Jan 1, 1980

By George E. Aiken

Modern high speed bucket wheel excavators (BWEs) can dig materials which power shovels can't handle without blasting. Yet these machines are not used in any large, open pit ore mines in the United States. American mining has been slow to use the wheel's special capabilities of high production volume at low cost, due perhaps to a traditional familiarity with shovels and draglines and/or the lack of data of BWE operation, design and cost. Of course, shovels and draglines can not be replaced by BWEs in all cases, but under suitable conditions bucket wheels can out-perform other conventional excavators and simultaneously permit significant operating savings. The latter aspect will become increasingly important to American mining men because as more low to medium grade orebodies are found in regions of thick overburden, better and cheaper ways of uncovering them must be developed. Typical of such areas are the thick alluvial fans of the Southwest and the glacial drift areas in northern regions. Much of this material would handle well with a wheel excavator without blasting, although ripping might be necessary in some cases.

Jan 1, 1966

During the last 15 years, the bucket wheel has become increasingly popular as a mining tool. Being a large-capacity continuous mining excavator, the machine offers low actual operating costs and low unit costs. Of German origin, the bucket wheel has now appeared on the American mining scene as well as in such other places as Australia, Northern Rhodesia, South Africa, Congo, Indonesia, and India. Patented in 1913, the first practical application waited until 1920 when a bucket wheel excavator was placed in operation at an open pit lignite mine in central Germany. This initial experiment met with little success due to difficulties in solving the technical problems of the machine's construction rather than to the design of the wheel itself.

Jan 9, 1960

By W. L. Price

Since they were first introduced in the United States in 1964, rail mounted bucket wheel stacker-reclaimers have gained wide acceptance by the coal burning power plant group. Other installations include those in phosphate and steel mill ore storage areas. First Installation in the U.S.A. Three basic types of bucketwheels for handling stored bulk materials are now being used in the U.S. Bucketwheel stacker-reclaimers came into use in the U.S.A. in 1964 at the Chalk Point power station built by the Potomac Electric Power Co. It was decided, after serious study, to install the first slewing-boom, rail mounted bucketwheel stacker-reclaimer at this installation. It was designed with a separately counter- weighted wheel boom because the fixed counterweight of the European designed bucketwheel made it possible for the machine to overturn backwards if the wheel rested on the ground due to a possible failure of the luffing system.

Jan 1, 1970

[Estimated Receipts Dues: Arrears $ 3,500.00 Current 108,115.00 New Members 11,937.00 In Advance 1,763.00 $125,315.00 Initiation Fees 7,250.00 Initiation Fees-Additional if increased to $20.00 7,250.00 Sale of Transactions....3,000.00 Sale of Binding 7,092.00 Sale of Magazine 2,913.00 Sale of Pamphlets 70.00 Sale of Indexes and Emmons Vols 313.00 Sale of Pyrometry 900.00 Sale of Raymond Vol 100.00 Interest received on Bank Balance 500.00 Interest received on Life Memberships 500.00 Advertising-Gross 27,000.00 Voluntary Subscriptions-Estimated 16,000.00 Income from James Douglas Fund 5,000.00 Total $203,503.00] [ ]

Jan 1, 1925

Estimated Receipts Dues Arrears $ 3,500 00 Current 108,115 00 New Members - 11,937 00 In Advance 1,763 00 $125,315 00 Initiation Fees - 7,250 00 Initiation Fees-Additional if increased to $20 00 7,250 00 Sale of Transactions 3,000 00 Sale of Binding 7,092 00 Sale of Magazine 2,913 00 Sale of Pamphlets 370 00 Sale of Indexes and Emmons Vols 313 00 Sale of Pyrometry 900 00 Sale of Raymond Vol 100 00 Interest received on Bank Balance . 500 00 Interest received on Life Memberships 500 00 Advertising-Gross 27,000 00 Voluntary Subscriptions-Estimated 16,000 00 Income from James Douglas Fund 5,000 00 Total $203,503 00

Jan 1, 1923

By Freeman Bishop

The Interior Department has been in a state of disarray for many months. At first this was attributed to Interior Secretary Walter Hickel's inability to anticipate how his words would be interpreted by Press-Radio-TV. But then the already disquieted ernployees in the Department became aware that plans were afoot to take bits and pieces of the various antipollution programs from Interior; Health, Education and Welfare: the Atomic Energy Commission and other agencies and lump them together into a new Federal agency. Interior, many predicted, would be a shell of its former robust self. Hardly had this rumor started to add to employee uneasiness before the other big shoe hit the floor. The new rumor had it that the Bureau of Mines was being stripped of most of its research functions and that the Office of Coal Research and allied research groups would be abolished altogether.

Jan 1, 1970

FIGURES covering appropriations recommended by the Budget Bureau for the Bureau of Mines at Washington for next year are now available and are as quoted below. APPROPRIATION BUDGET APPROPRIATION 1928 1929 General Expenses $ 86,000` $ 86,000 Investigating Mine Accidents 386,470 399,470 Mining Investigations in Alaska.. 10,860 10,860 Operating Mine Rescue Cars and Stations 327,630 342,630 Testing Fuel 154,000 158,500 Mineral Mining Investigations.... 99,570 125,000 Oil, Gas and Oil-Shale Investiga- tions 198,260 198,260 Oil-Shale Investigations 5,000 80,000 Expenses Mining Experiment Sta- tions 173,000 173,000 Care, etc., Buildings and Grounds, Pittsburgh, Pa 71,360 76,360 Maintenance and Operation, Fuel Yards Balance Balance Helium Investigations :.... 75,000 75,000 Helium Production and Conserva- tion 1,063,000 462.000 Potash Investigations 100,000 100,000 Economics of Mineral Industries. . 225,000 275,000 Totals $2,975,150 $2,562,080

Jan 1, 1928

Jan 1, 1889

Jan 1, 1899

By William Hutton Blauvelt

An official of one of the prominent iron companies of the South recently made the following statement during a discussion of the present conditions of the Southern iron business: " The trouble with us in the South has been that we have been satisfied to buy iron and coal lands, build blast-furnaces, and make pig-iron. We stopped at pig-iron, and as a result we are all poor. The South needs diversified industries, and needs to work up its raw products into articles the Southern market can use. If we had realized this sooner, some of us might now be rich." The South is awakening to this view, and in the Birmingham district alone one basic steel-mill is already in operation, and in a year's time another and much larger one will be turning out rails and shapes, with rod- and wire-mills in prospect. It is to chronicle another metallurgical step forward in the same district that I have prepared the following description of the new by-product retort coke-oven plant recently put in opera-

Jan 1, 1899

By Jacob T. Wainwright

This stove has been designed to meet the requirements of a fur nave that must be operated with either a reducing or a neutral flame ; and more particularly to make feasible the operating of re duction-furnaces with the cheaper grades of gas-fuel, which has heretofore been impracticable. In general, cheap gas-fuels result from incomplete combustion, and, being suited for further combustion, answer very well for heat ing purposes; and high temperatures may be attained with them, when they are used in conjunction with regenerative stoves. But, in operating a reduction-furnace, a high temperature is not the only requirement. It is also necessary that the fuel shall not be cansumed beyond a certain degree, in order to insure a re ducing flame for the reduction-process ; consequently, it becomes necessary to dispense with combustion as much as possible previous to the use of the fuel-gases in the reduction-furnace. Moreover, these gases must be preheated to a high degree, in order that a sufficient temperature may be maintained in the furnace; and, since this preheating cannot be accomplished by a previous, partial combustion of the gases themselves, it follows that the stoves for pre heating these gases should be heated to as high degree as it is pos sible to attain with an inferior fuel. This result can best be accom plished by complete combustion of the heating gases, and is further facilitated by preheating all of the air and gas used for this com plete combustion. It is more particularly desirable to preheat the air, since the combustible gases used may generally be obtained directly from the furnace, or gas-producer. The reducing gases, escaping from a gas-fuel reduction-furnace, are capable of considerable further dilution with air to secure com plete combustion, and consequently may be utilized for heating the stove to a high temperature, provided the air be sufficiently preheated.

Jan 1, 1889

By H. O. Hofman

INSTITUTE OF TECHNOLOGY, In deternlining experimentally the fusibility of clays, two kinds of methods may be distinguished—the direct and the indirect. Of the direct methods, that of Seger has found

Jan 1, 1899

By Richard E. Chism

The dry methods of assaying mercury-ores and other combinations of mercury all rest upon the volatility of this metal as a beginning. After the separation of the mercury in the form of vapor from the matrix upon which the assay is performed, the mercurial vapors are either condensed upon cold surfaces or received upon a gold plate into which the mercury is absorbed.

Jan 1, 1899

By Alfred E. Hunt

In a paper written for the Boston meeting of February, 1888 (Trans., xvi., 693), on "Some Recent Improvements in OpenHearth Steel Practice," the writer described the reducing agent used by the Carbon Iron Company as "a peculiar graphite from Cranston, near Providence, R. I." Upon an application pending at that time, a patent has since been issued as number 259,795, to Mr. Matthew Graff, for the use of solid carbonaceous matter in the form of coke, charcoal, gas carbon, bituminous or anthracite coal, ground to the size of coarse sand and then coated with a mash of lime, magnesia, clay, or other material of a like character, as an agent to reduce metallic oxides. An amount of this prepared carbonaceous matter equal to from 25 to 30 per cent. of the weight of the ore treated is required to perform the complete reduction. The idea is that the carbonaceous matter is protected against rapid combustion by a suitable coating of some inert material, so that, in effect, its action as a reducing agent will be similar to that of the Cranston graphite previously used, allowing the solid carbon to remain without combustion in intimate mixture with the iron oxide at a temperature sufficiently high to reduce the ore and in some cases to melt the matrix in which the iron is held. In the present practice of the Carbon Iron Company, the use of graphite, except for the formation of bottoms of the reverberatory furnaces in which the reduction is performed, has been entirely abandoned, and " retarded coke," as it is called at the works, has taken its place. Five hundred and fifty pounds of Connellsville coke is ground in a pan to 16-mesh fineness, or is taken in the form of ordinary coke-dust, and made into a hollow basin on the mixingfloor ; and seven bucketfuls of a wash composed of equal parts of lime and fire-clay, mixed in water to the consistency of thin cream,

Jan 1, 1889

By William B. Potter

We have come together on this occasion, as so often before the members of the Institute have met in friendly council, to hear and discuss whatever investigation, observation, and experience during the past months may have developed of value or interest to the many departments of knowledge and practice represented in this association. The member, possessed of the true scientific spirit which this Institute is especially intended to foster, brings here the results of his experience and study unrestrained by fear of giving undue advantage to competitor or rival. He appreciates, moreover, the responsibilities of membership and his duty to the cause, and how much is to be gained by himself from the keen but friendly criticism of his fellow-workers and even by the suggestions that may come of shrewd question or chance remark from those who labor in other but related fields.

Jan 1, 1889

By Ralph H. Sweetser

When a furnace-manager is '(blowing in," he generally has no time to consider the composition of the waste gas, and does not bother with it, except to take care that he does not get " gassed." Moreover, the analysis of the gases while the wood is still burning has not much to do with the economy of the normal working of the furnace; yet, on account of the deadly effects of the " blowing-in " gas when inhaled, and of its high explosive qualities, it is interesting to know its composition. In the Transactions there is no record of the analysis of the gas during an up-to-date " blowing-in." Even in Mr. Whiting's admirable paper (Trans., xx., 280) the reported analyses did

Jan 1, 1899

By Edgar S. Cook

The Warwick furnace at Pottstown, Pa., constructed for anthracite fuel, is, as may be remembered, 554 feet high, with 15; feet bosh. The actual working height from stock-line to bottom is only 474 feet, the bell-and-hopper taking up 8 feet. During the year 1886 we used mixed fuel, in the proportion of three-fourths anthracite and one-fourth coke. The total product of iron was 30,6299 tons of 2280 lbs., being a weekly average of 589 tons, including all ordinary and extraordinary stoppages. Deducting the latter, the weekly average would be about 600 tons. The fuel-consumption for the year was 1.2 tons per ton of iron, while the ore-mixture yielded 52 per cent. of iron. For about two months during the summer of 1887 we were obliged to run on anthracite exclusively, owing to the Connellsville coke strike. In the fall of 1885, in relining the furnace, the crucible had been built 8 feet 9 inches in diameter, with the view of using regularly one-quarter of coke (the largest previous diameter having been 7 feet 5 inches), and we felt somewhat apprehensive of the results when compelled to use anthracite only. The average of seven weeks' run on coal, as compared with the average of the seven corresponding weeks of 1886 (using one-quarter coke), was as follows:

Jan 1, 1889

By F. V. Greene

This paper is based on my experience in the use of asphalt, for paving and other purposes, during the last ten years, part of the

Jan 1, 1889