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By D. W. Kestner

Recent developments and trends in the state of the art as being commercially applied to the pelletizing and sintering of metallic ores, concentrates and reverts will be reviewed. Both ferrous and non-ferrous materials will be covered. The influence of environmental considerations on the decision to build, the process selection, and design of the plants will be discussed. Use of coal in iron ore pellet induration will also be reviewed as the availability and price structure of oil and gas becomes a consideration to the plant operators.

Jan 1, 1980

By Douglas A. Anderson

We have instrumented well-controlled free-face blasts with six- component borehole strain gages, in order to determine the complete strain tensor as a function of time due to explosive loading. The strain tensors have been diagonalized to determine the principal strain time-histories, and further processed to determine the octahedral shear strains as a function of time. Principal strain time-histories, when compared with a computer model, indicate the arrival of various direct and reflected phases. Strong shear strains coincide with the expected arrival time of shear waves. These shear waves are probably instrumental in the fragmentation of confined rock due to explosive loading, and should be incorporated in models of the fragmentation process.

Jan 1, 1984

By Lawrence Adler

A lag apparent in the mining engineering field. While mining will continue as an essential industry, a revitalized profession will be required for national well-being. Specific problems facing the profession include: - a conflict between its design, production and management components, which affect the engineers on a daily basis; - a credibility gap in public matters that is so extreme, government action approaches punitive in degree, and - historical decreases in the number of degree-offering departments in the face of an increasing demand for graduates. A turnaround in these areas could result in attracting into the industry, highly creative, capable, and socially concerned engineers. By improving the quality of undergraduate education, the effectiveness of each entering engineer would be multiplied. This is another way to combat the chronic shortage of trained mining engineers. At the same time, it would set a significant example for other professions in the throes of overspecialization. A revival of the mining profession can be accomplished only during the formative training years of its future practitioners. An educator's role would be pivotal in this effort.

Jan 3, 1975

By O. Saeki

Dolomite-fluxed pellets have been produced at Kakogawa Works, Kobe Steel, Ltd., since August, 1975. The pellets contain 5.5 % dolomite and have a basicity (CaO/Si02) of 1.3. By charging 30-50 % of dolomite-fluxed pellets into the two large blast furnaces at Kakogawa, a low fuel rate of 450 kg per ton of pellets has been achieved with better furnace permeability and gas utilization. Laboratory studies show that dolomite-fluxed pellets have excellent high temperature properties, and that their softening and melting-down temperatures are about 50°C higher than those of lime-fluxed pellets, and that reducibility at 1250°C is increased from 25 to 70 %.

Jan 1, 1977

By J. K. Lovrien

A Link-Belt roller-bearing conveyor system was in- stalled recently at the Gross-Marble mine of the Oliver Iron Mining Co. at Marble, Minn., for removal of overburden and lean ore. The material, consisting of clay, sand, gravel, and glacial boulders. is excavated by an electrically operated walking dragline equipped with a 10 cu yd bucket working from a boom approximately 150 ft long. This machine loads into a receiving hopper of a rail-mounted screening plant in 45 second cycles. A manganese steel apron feeder under the receiving hopper delivers to an elliptical grizzly, from which the oversize boulders and extraneous material, by way of an apron conveyor, arc loaded into refuse haulage trucks.

Jan 12, 1951

By John D. Weibmer

A remarkably simple construction system that derives its internal stability from metal straps buried in backfill is finding diverse mine applications, ranging from rock crusher headwalls to massive slot coal storage facilities. Reinforced Earth (Re/Earth), the system trade name of Reinforced Earth Co., is proving itself 20-50% less expensive than alternative earth embankment structures, and in the case of cast-in-place concrete walls, six to seven times faster to erect. While the majority of applications are in the realm of civil engineering-projects such as retaining walls, bridge abutments, slide buttresses, and containment dikes-a growing proportion is mine related. Of the estimated 120 Reinforced Earth projects that will be completed this year, company president David P. McKittrick expects mining to account for about 20% of the business volume.

Jan 8, 1978

By A. B. Bowman

Banner Mining Co. became interested in this Tucson area early in 1950, and after several months of reconnaissance work, a lease-option purchase agreement was concluded on the Mineral Hill property which allowed time for considerable exploration and development work. Unwatering of the mine began in August 1951 after electric power lines were extended from nearby Tucson. The unwatering and rehabilitation work was done under a Defense Minerals Exploration Administration project and was completed in December 1952 after about 15 months of tedious work. The mine had been under water for more than 30 years with resulting cave-ins and timber deterioration. In some badly caved areas spiling was necessary to reopen the old drifts and crosscuts.

Nov 1, 1955

By G. E. Karantzavelos

Anew flotation process to recover alunite from low-grade alunite ores is described. The process begins with run-of-mine ore, reduced to less than 5 mm (0.2 in.), being preconditioned with the reagents before grinding and alunite flotation. From the preconditioning step, ore particles, impregnated with reagents, form pellets that subsequently disintegrate into the pulp during grinding. The second step is basically a standard alunite flotation step. Pilot plant test results show that an alunite concentrate assaying at least 85% alunite and less than 5% silica can be produced. Laboratory and pilot plant results were in excellent agreement, indicating that the new process is a viable means of alunite beneficiation. Plant results, using the new process, were superior to results from conventional alunite flotation procedure.

Jan 1, 1986

By M. J. Scoble, N. Rowlands, L. Piciacchia

Pronounced non-linear behaviour of mine backfill arises from the influence of confining pressure, cementing agent content, curing time, void ratio and water content. Past research into backfill behaviour under stress is reviewed and related to the needs for constitutive laws which can be integrated into numerical modelling for mine design where structures employ backfill support. A method for representing non-linear backfill behaviour is proposed, which is based upon numerical regression treatment of triaxial laboratory data. The non-linear behaviour observed from a program of laboratory triaxial testing of cemented hydraulic backfill is presented. The particular influence of confining stress and curing duration is high- lighted. The paper concludes by considering the alternative means of accounting for such behaviour in mine design.

Jan 1, 1984

By Henry J. Schwellenbach

Lack of a system in scheduling the replacement of capital equipment can result in emergency purchases of units which may later be found unsuitable for the job. New York Trap Rock Corp., which produces crushed stone for use as construction aggregate, was faced with just such a situation some years ago. The company replaced capital equipment only when machinery in use was no longer serviceable, or when there was an obvious need for different equipment. Operating and maintenance costs were generally neglected because an efficient method was lacking. New York Trap Rock has four plants located along the Hudson River, all within 70 miles of New York City. Crushed stone output-6 million tons a year-is moved to markets in metropolitan New York, New Jersey, and Long Island areas by water transport. Customers are contractors with ready-mix concrete and asphalt plants located on the water.

Jan 10, 1959

By T. M. Chatard, Cabell Whitehead

The Republic mine, situated forty miles from Marcus, a station on the Spokane Falls and Northern Railroad, in the northeastern part of the State of Washington, was located in 1896, but no development-work was dolie until the spring of 1897. While much of the ore mined since then has been rich enough for shipment to smelters, a method of locally treating the lower-grade ores soon became a matter of prime importance, because only about 40 per cent. of the values could be recovered by plain amalgamation, even with ores assaying 4 to 5 ounces of gold per ton. Experiments with cyanidation, in various ways, led to the adoption of the Pelatan-Clerici process and the erection on this system of a 10-ton experimental plant, which was later increased to a capacity of 35 tons per day. The extractions by this process showed much improvement over previous work, especially when the ore was crushed to

Jan 1, 1901

By John J. Childress, Russell L. Cook

Stringent environmental regulations, which have limited the use of sludge ponds, coupled with the economic incentive to clean more coal or to add fine coal cleaning additions to existing preparation plants have increased the use of static thickeners in preparation plants. The Lamella Gravity Settler, sometimes designated Lamella Thickener, is a shallow depth sedimentation device which has been applied in a variety of industrial process and wastewater control projects in place of the conventional raked thickeners. This paper presents the theory and design of the Lamella Thickener, as well as describing the operating results from several full scale installations in a variety of Appalachian preparation plants.

Jan 5, 1978

Oscar Rohn was born in Jackson, Wis., June 27, 1870. He attended the University of Wisconsin and there gained from Professor Van Hise his inspiration for scientific effort and useful attainment. While a student at Wisconsin he was interested in athletics and was a member of the first eight-oared crew that Wisconsin sent to compete with Eastern crews at Poughkeepsie. He was an instructor in the gymnasium for several years. He received his B. S. in 1895 at Wisconsin, specializing in engineering and geology. 1229

Jan 1, 1924

By Eugene Guccione

The domestic iron and steel industry is a vital and major segment of the US economy. Including its employees in coal mining, iron ore mining, limestone quarrying, and related transportation, the industry directly provides jobs for approximately 750,000 people, has a $10 billion annual payroll, and indirectly supports a substantial volume of employment for the entire country. Because of its size and visibility, if nothing else, the US iron and steel industry has always been an easy target of attack and has often been subjected to a great deal of political sound and fury. Today, the industry has different troubles and is fighting for survival: it is faced with spiralling costs, inadequate earnings, labor unrest, foreign competition, government over-regulation, an acute shortage of investment capital, and an all-time high debt burden.

Jan 11, 1975

By John C. LaScola, David M. Hyman, William P. Diamond

The U.S. Department of the Interior, Bureau of Mines, has established a computer-implemented coalbed methane data base containing data representing over 2,000 coal samples from approximately 250 coalbeds located in 17 States and one Canadian Province. Space for approximately 130 sample characteristics is reserved for each sample record and is divided for access efficiency into three separate physical files. A software package was written to provide a user-friendly environment in which the three files can be manipulated simultaneously. These files can be used interactively in DATATRIEVE 11, a commercially available sorting, retrieval, and report-writing software package or in any FORTRAN-compatible system for statistical analysis. The data base has been established for coalbed methane research in response to the health and safety needs of the mining industry. Possible applications of the data base include mine planning related to the occurrence of gas, as well as delineating areas of resource recovery and utilization.

Jan 1, 1983

The American Federation of Labor adopted 'the following resolution at its Atlantic City convention: "WHEREAS, scientific research and the technical application of results of research from a fundamental basis upon which the development of our industries, manufacturing, agriculture, mining, and others must rest; and WHEREAS, the productivity of industry is greatly increased by the technical application of the results of scientific research in physics, chemistry, biology; and geology, in engineering and "agriculture, and related sciences; and the health and well-being not only of the workers but, of the whole population as well, are dependent upon advances in medicine and sanitation; so that the value of scientific advancement to the welfare of the nation is many times greater than the cost of the necessary research; and WHEREAS, the increased productivity of industry resulting from scientific research is a most potent factor in the ever-increasing struggle of the workers to raise their, standards of living, and the importance of this factor must steadily increase since there is a limit beyond which the average standard of living of the whole population cannot progress by the usual methods of re-adjustment, which limit can only be raised by research and the utilization of the results of research in industry;. and

Jan 8, 1919

[ ] TUNNELS TO BINS. Originally designed for tunnel work, the strong lightweight liner plates used to construct this 30-ft diameter, 31-ft high, aggregate storage bin have several advantages. Bins and conveyor to tunnels can be quickly erected in any season, for permanent service, or to be salvaged and reused. Armco Steel Corp. (16) ROLLER CHAIN: Engineering Data Book No. 2457 published by Link-Belt Co. is a comprehensive 148-page volume on roller chain and its application. Detailed engineering information covers installation, maintenance and lubrication of chains for drives, conveyors, and sprocket wheels. The book covers selection of drives to meet both standard and special installations. (17) LABORATORIES: The Fisher Scientific Co's. line of 21 basic units of standardized steel laboratory furniture is described in catalog no. 25. The Unitized line was designed to combine the advantages of custom installation with the convenience of selection, delivery and continued flexibility that goes with ready-made units. (18) PUMPS: Two similar, but functionally different types of vertical centrifugal wet-pit pumps; a heavy duty bilge pump for handling solids-free liquids and drainage; and a screenless sewage ejector, constructed to handle sewage and solids carrying liquid; are illustrated in a bulletin from Yeomans Bros. Co.

Jan 1, 1952

By Alvin L. Langstaff, Harold D. Raymond

The design of entry systems and mining panels in room-and-pillar oil shale mines seeks to optimize extraction while ensuring both short- and long-term stability of mine openings. Important criteria for optimization include the definition of allowable roof spans and minimum pillar dimensions. Factors considered pertinent to the design of roof spans and pillars are discussed in this paper. They include, but are not limited to, physical properties and grade of the oil shale, depth of burial, presence and frequency of partings and joints and adverse effects of blasting. Also discussed briefly are some of the ventilation and production considerations in mine design.

Jan 1, 1984

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

AN indication that Mesabi Range iron use companies may develop their own flotation processes for low grade iron ores is the report that Cleveland Cliffs Iron Co. is adopting a variation of one of the oldest known methods at its new Michigan treatment plant. Basically, the method involves using fatty acids and fuel oil reagents. The idea was developed many years ago and should be free of patent control. With other laboratories working on the same tack, it seems to be a pretty good bet that they will come up with their own processes. Any outside process will have to offer considerable advantage or low royalty rate to get consideration. Much of the appeal of the fatty acid process is the cheapness of the reagent. One source is pulp paper liquor in semi-refined form. With stream pollution legislation acting as a strong pressure, paper companies have been seeking ways to dispose of the material. Wisconsin has even attempted to use it for road binder.

Jan 5, 1953