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By Frank L. Hess

In 1876 cassiterite was identified in the placer gold from the northern Black Hills, and such a mixture could have come only from Nigger Hill or one of the streams draining the hill, because in no other hart of the northern hills have cassiterite anti gold been found together. Nigger Hill is in western Lawrence County, South Dakota, and on it is the little camp of Tinton. The Wyoming line runs along the west side of the hill and crosses the ridge which is the hill's continuation about miles north-northwest of Tinton.

Jan 1, 1938

By Angus D. Campbell

Introduction In the Twentieth Annual Report of the Mcintyre Porcupine Mines, Limited, for the year ending March 31st, 1932, the General Manager, Mr. R. J. Ennis, said: "During the period under review, the plans outlined in last year's report have been completed, and all operations have been centralized in the new plant adjacent to No. 11 shaft. The new mill went into operation on May 27th and attained its rated capacity of 2,000 tons per day on November 15th. The new shops, warehouse, change-house, and general offices were occupied on December 1st, consummating the change from the old to the new plant ... "Silicosis is now definitely recognized as an industrial disease, and progresses rapidly when associated with tuberculosis. In an effort to combat its prevalence and progress, the new change-house was designed to build up the men's resistance to this and other forms of disease. It provides for a complete change from underground to street clothing, with a shower bath and solarium treatment in the interval. 'Unfortunately, in almost every goldmine, a very small percentage of the work-men are not adverse to taking some of the high-grade ore for their own purpose. This, in turn, tends to cast suspicion upon the honourable as well as the dishonorable employees. The new change-house routine discourages this practice and eliminates unjust suspicion, to the satisfaction of all concerned with the Company's operations".

Jan 1, 1933

By Roger L. Hulette

Mt. Newman Mining Co. is now completing an expansion program, begun even before initial construction was complete, which will result in facilities with the ability to ship over 30 million tons of iron ore per year by early 1973. Confidence in such rapid future growth was evidenced by careful planning for the future expansion of those facilities provided for initial operation of the project which first shipped ore on 1 April 1969. Ore sales contracts totaling more than 300 million tons have been negotiated, thus justifying the optimism which led the joint venturers to provide over $200 million in initial investment and a like amount in capital required to finance the continuing expansion program. Members of the Mt. Newman Joint Venture are: Amax Iron Ore Corporation - 25% (a subsidiary of American Metals Climax) Pilbara Iron Ltd. - 30% (a subsidiary of Colonial Sugar Refining) Dampier Mining Ltd. - 30% (a subsidiary of Broken Hill Proprietary) Seltrust Iron Ore Ltd. - 5% (a subsidiary of Selection Trust Ltd. of London) ? Mitsui C. Itoh Iron Ore Pty. Ltd. - 10% Mt. Newman Mining Co. Pty. Ltd. manages the project on behalf of the five companies which make up the joint venture.

Jan 1, 1972

By Hugh Roberts

During 1916 and 1917, the E. J. Longyear Co. of Minneapolis, Minn., carried out a campaign of exploration for nickel-copper ore in the Sudbury District of Ontario. The work was initiated by W. E. Smith, a resident of Sudbury, who called the attention of W. J. Mead, Chief geologist. The E. J. Longyear Co., to the fact that explorable lands in the Sudbury District were still available. Five diamond drills were employed, and holes were drilled in the townships of Levack, Trill, Denison, Blezard; Garson, Falconbridge and MacLennan. The general map of the District, Fig. 1, shows the distribution of the lands chosen. As a result of this exploration, a large body of nickel and copper ore has been found in the western part of the Township of Falconbridge. This property lies in the eastern part of the Sudbury District, east of the Garson mine.

Jan 2, 1918

By W. E. Coates

The social ecology of surface mining in urban areas is illustrated by a case study of a recent application for the opening of a new gravel pit in the city of Guelph, including the design of a progressive extraction-rehabilitation sequence for the property, investigation of the ecological impact of the proposed operation, history of the application procedure for a zoning change and the relationship of the operating plan to provincial legislation controlling surface mining.

Jan 1, 1972

By Gary Brieley

Until well into the 20th century, most construction work was performed under the auspices of a master builder or in a manner that would be described today as design-build. In addition, many civil engineers served as ?interns? under the tutelage of a master builder in order to learn how to design and construct a certain type of structure. This was certainly the case for tunneling projects with various individuals having been identified as tunneling experts as a result of successfully completed projects The master builder approach began to change in the early 1900s to a model that would be referred to today as design-bid-build. A design-bid-build approach to project procurement gives the owner more control over the final product and al-lows the contractor to know exactly what is expected of them before the work is constructed. As a result of this transition in project procurement, civil engineering schools placed a greater emphasis on the training of ?design? professionals. This article will document how the training of tunnel design professionals progressed within the United States. Although it is difficult to generalize about the hundreds of tunnels that were constructed in the first four decades of the 20th century, there is one project that stands out as having resulted in a university program related directly to tunneling and that is the Chicago Subway. During a visit to the United States in 1938, Dr. Karl Terzaghi met a student named Ralph Peck who was then studying at Harvard University in a pro-gram established by Arthur Casagrande. Shortly thereafter, Terzaghi traveled to Chicago for a lecture and was asked to consult on the Chicago subway project that was then under construction. The Chicago subway was being constructed in clay, and the owners were worried about possible settlements to nearby buildings. Terzaghi asked Peck to serve as his field engineer for that project. Thus was established one of the most productive relationships in the history of civil engineering in the United States. Peck, who would become Dr. Peck, moved to Chicago in 1939 to participate in an extensive research project that con-tinued until subway construction was halted in 1941 because of World War II. During that time, the cost of subway construction in Chicago was reduced substantially as a result of Peck?s observations and Terzaghi?s recommendations. In fact, it was reported that subway construction in Chicago cost less than one-half of similar projects in London even though the clay in London is considerably stiffer compared to Chicago. Upon the completion of his work on the Chicago Subway, Peck accepted a professorship with the University of Illinois in Champaign/Urbana.

Jun 1, 2010

By N. E. Hanna

To be approved for use in underground coal mines in the United States, explosives and blasting devices must pass certain safety tests prescribed by the Federal Bureau of Mines. These tests are described in Schedule 1-G4/ (explosives) and Schedule 26A5/ (blasting devices). An explosive or blasting device that passes the appropriate tests is placed on the active permissible list. As this list is subject to continuous revision, it has been the practice of the Bureau of Mines to publish periodically the names of explosives and blasting devices that have been added to the active list, as well as those that have been transferred to the inactive list; changes in brand names also are reported. The present circular gives all explosives and blasting devices on the active permissible list as of December 31, 1957, and shows all changes, additions, and transfers in that list between December 31, 1951,6/ and December 31, 1957.

Jan 1, 1958

In seeking to improve the economic performance of mines, the management or human aspects are usually seen to be quite seperate from, and more significant than, the technical aspects. There are obvious aspects of industrial relations, man-management, skills training and supervision that are currently the focus of efforts to improve the productivity and quality of the mining process. However technology also has a lot to offer. Analysis of the costs involved suggests that innovations leading to improvement in the productivity of the excavation and transport of overburden and the recovery of coal (both in the mine and preperation plant) can lead to improvements in the economic performance of a mine that may outstrip the obvious non-technical or management opportunities for improvement. While there are some innovations currently being investigated within the industry that relate to the design of mining equipment, the type of machinery being used in open cut mines has not changed dramatically over the last twenty five years. It is also likely that mining equipment will remain essentially of the same form in the forseeable future. If significant improvements to mining performance are to be achieved other than by futher increases in the scale of machinery, then we need to seek ways to operate these same types of machines in a more productive and controlled manner. This paper discusses the identification of mining processes the improvement of which is likely to have a significant effect on mining costs and performance. Some areas of current research are discussed and potentially fruitful areas for future development are identified.

Jan 1, 1991

By J. E. Shelton

Flotation tests are described on samples of two lowgrade nickeliferous ores of Oregon and Washington. The sample from the Congress mine, Ferry County, Wash., contained 1.2 percent Ni, occurring chiefly as millerite. The sample from the Shamrock mine, Jackson County, Oreg., contained 2.20 percent Ni and 0.78 percent Cu occurring chiefly as pentlandite, nickeliferous pyrrhotite, and chalcopyrite. The millerite in the Congress ore was concentrated by flotatioin with aulfydric collectors in a series of locked tests to recover 73 percent of the nickel as a 7 percent bulk concentrate. By successively regrinding and floating the bulk concentrate, it was further concentrated to 12.4 percent Ni at a recovery of 59 percent and 21.8 percent Ni at a recovery of 50 percent. Attempts at selective concentration of the copper-nickel Shamrock ore were only partly successful because of the intimate association of pentlandite and chalcopyrite. The nickel concentrate, which contained 86 percent of the nickel, had an analysis of 4.42 percent Ni and 1.03 percent Cu. The copper concentrate had an analysis of 18.8 percent Cu and 1.96 percent Ni and contained 48.5 percent of the copper. A bulk sulfide concentrate contained 92 percent of the copper and 01 per¬cent of the nickel and had an analysis of 4.17 percent Ni and 1.63 percent Cu.

Jan 1, 1956

By Michael Hughes, Selva Selvamohan, Ray Costa

"Cutoff walls are commonly used to mitigate underseepage problems for levee remediation projects. At abrupt changes in seepage cutoff wall depths there is a potential for water to flow around the back of the deeper cutoff wall leading to elevated seepage pressures on the landside that could result in exit gradients exceeding design criteria. This condition is referred to as end-around-effects and is a complex problem that requires detailed and time consuming 3-D numerical modeling to represent accurately. This paper presents a simple approach for assessing end-around-effects using the results of 2- D seepage analysis to determine if lateral extension of the deeper portion of the cutoff wall is required. This simplified approach provides a pragmatic solution to a complex 3-D problem. The presented procedure was used as part of the Feather River West Levee Project in Yuba City, California, to assess end-around-effects at 26 locations. The results showed that wall extensions of up to 100 feet were needed at only 2 locations.INTRODUCTIONAs the lead geotechnical consultant for the Feather River West Levee Project, AECOM were responsible for designing levee remediation works for approximately 35 miles of levee protecting the area around Yuba City, California, and communities to the north and south. Due to land use constraints, seepage cutoff walls were the main remediation alternative selected to address underseepage issues for the project.As part of the design review process, the California Department of Water Resources (DWR) requested AECOM to look at 26 locations along the levee alignment where the depth of cutoff wall changed abruptly from shallow to deep, or vice versa. At these locations there was the potential for seepage pressures to pass behind the deeper section of cutoff wall and stress the blanket layer landward of the cutoff wall. A condition referred to as end-around-effects.End-around-effects involve complex 3-D ground conditions that have traditionally been addressed by laterally extending the deeper section of cutoff wall an arbitrary distance based solely on engineering judgment. In discussions with DWR, AECOM developed a simple procedure to provide a more objective assessment of end-around-effects without the need for detailed and time consuming analysis. This procedure allows the engineer to make an informed decision of whether end-around-effects are a problem at the location of a cutoff wall transition rather than laterally extending the deeper section of cutoff wall an arbitrary distance based on engineering judgment alone."

Jan 1, 2015

By Robert B Sosman

The relative temperature distribution within a coke oven and among the ovens in a battery can be obtained automatically for the operator's guidance by sighting a total-radiation pyrometer on the face of the coke as it is pushed out, and recording the surface temperature. Keeping the instrument clean and keeping its view of the coke unobstructed by smoke and dust are the principal problems. Typical records from three plants are presented in this paper, showing that the temperature patterns are reproducible. Development OF Method The method of coke pyrometry described in this paper was introduced in 1936 by E. A. Lee, then Assistant Superintendent, now Superintendent, of the Coke Plant at Lorain Works, National Tube Co., Lorain, Ohio. At the request of the Coke Committee of the United States Steel Corporation, the Research Laboratory of the Corporation undertook to adapt the method to the somewhat different conditions met with at the Gary Works of the Carnegie-Illinois Steel Corporation, Gary, Ind., and at the Clairton Works of the same Corporation at Clairton, Pa. This work was done in cooperation with the Leeds and Northrup Co. of Philadelphia and later with the Brown Instrument Co. Division of Minneapolis-Honeywell Regulator Co., Philadelphia. We of the Research Laboratory wish to express our appreci- ation of the courtesies extended by Mr. Lee, by A. N. Cole, Superintendent of the Gary coke plant, and by D. P. Finney, Assistant General Superintendent in charge of coke-plant operations at Clairton. We are also indebted to the instrument companies for the loan of a part of the equipment. At Gary and Clairton the instruments were installed and various experiments were made by J. W. Bain, of the Research Laboratory of the United States Steel Corporation. Pyrometry of Coke The coke inside a by-product oven is almost completely inaccessible to pyro-metric instruments. The temperature in the walls can conceivably be measured with thermocouples, but the atmosphere is usually strongly reducing, a condition well known to be destructive to the accuracy of the customary high-temperature couples. In some plants, periodic readings are taken with an optical pyrometer sighted into the top of the combustion flues. This is a useful measure for safety and general control, as it tends to prevent the damage that would result from overheating of the ovens. It does not, however, tell much about the temperature of the coke itself, because of the continually changing gradient in the wall between the coke and the combustion chamber. The best indication of the temperature of the coke itself must therefore be obtained by observation of the product as it is pushed out of the oven. The human eye is very sensitive to variations in brightness of a surface, and particularly to differences in brightness over a continuous hot surface.

Jan 1, 1943

By Robert B. Sosman

The relative temperature distribution within a coke oven and among the ovens in a battery can be obtained automatically for the operator's guidance by sighting a total-radiation pyrometer on the face of the coke as it is pushed out, and recording the surface temperature. Keeping the instrument clean and keeping its view of the coke unobstructed by smoke and dust are the principal problems. Typical records from three plants are presented in this paper, showing that the temperature patterns are reproducible. Development OF Method The method of coke pyrometry described in this paper was introduced in 1936 by E. A. Lee, then Assistant Superintendent, now Superintendent, of the Coke Plant at Lorain Works, National Tube Co., Lorain, Ohio. At the request of the Coke Committee of the United States Steel Corporation, the Research Laboratory of the Corporation undertook to adapt the method to the somewhat different conditions met with at the Gary Works of the Carnegie-Illinois Steel Corporation, Gary, Ind., and at the Clairton Works of the same Corporation at Clairton, Pa. This work was done in cooperation with the Leeds and Northrup Co. of Philadelphia and later with the Brown Instrument Co. Division of Minneapolis-Honeywell Regulator Co., Philadelphia. We of the Research Laboratory wish to express our appreci- ation of the courtesies extended by Mr. Lee, by A. N. Cole, Superintendent of the Gary coke plant, and by D. P. Finney, Assistant General Superintendent in charge of coke-plant operations at Clairton. We are also indebted to the instrument companies for the loan of a part of the equipment. At Gary and Clairton the instruments were installed and various experiments were made by J. W. Bain, of the Research Laboratory of the United States Steel Corporation. Pyrometry of Coke The coke inside a by-product oven is almost completely inaccessible to pyro-metric instruments. The temperature in the walls can conceivably be measured with thermocouples, but the atmosphere is usually strongly reducing, a condition well known to be destructive to the accuracy of the customary high-temperature couples. In some plants, periodic readings are taken with an optical pyrometer sighted into the top of the combustion flues. This is a useful measure for safety and general control, as it tends to prevent the damage that would result from overheating of the ovens. It does not, however, tell much about the temperature of the coke itself, because of the continually changing gradient in the wall between the coke and the combustion chamber. The best indication of the temperature of the coke itself must therefore be obtained by observation of the product as it is pushed out of the oven. The human eye is very sensitive to variations in brightness of a surface, and particularly to differences in brightness over a continuous hot surface.

Jan 1, 1943

By Jones JJ

A laboratory study of size segregation is described using a model of a Paul Wurth hopper industrailly employed for blast furnace charg- ing purposes. Experimental charge materials used in the study were glass ballotin.i (1-4mm dia.) and sinter fines (0.25-4mm). The tracer material employed consisted of coloured glass beads. The results of the study show that the discharge stream from a Paul Wurth hopper is characterised by an initial negative segregation followed by a positive segregation and that this segregation pattern is a property of the hopper geometry and the filling conditions. A simple computer model based on experimental tracer concentration results is proposed. The measured segregation results and those predicted by the model show close agreement. Application of the results with special reference to the effect of size segregation on charge permeability in blast furnaces is also included.

Jan 1, 1984

By G S. B Karunatillake

Following a pre-feasibility study, Mount Isa Mines commenced a feasibility study on the deposit of the George Fisher Mine in May 1997. Board approval was granted in May 1998 to construct a 2.5 million tonne per annum mine and to upgrade existing concentrator and smelter facilities. The world-class George Fisher zinc-lead-silver deposit is located approximately 22 kilometres north of the city of Mount Isa, in north-west Queensland and is 2.6 kilometres north of the existing Hilton Mine. It will be a large-scale underground mine, sustaining a profitable zinc-lead-silver business in Mount Isa for at least ten years. This paper will outline the details of the mine that was developed during the feasibility and design phase. It will include a description of the mining methods, ventilation, fill, ore handling, services and infrastructure. The utilisation of existing assets and the development of innovative ideas were essential to the successful economic development of the George Fisher Mine.

Jan 1, 2000

By Christie GB, Mainwaring DE, Leong YK

High solids brown coal slurries have been prepared with concentrations approaching those achieved with bituminous black coals. The high inherent water content and macroporosity of Victorian brown coals have been reduced in a controlled manner by chemical and mechanical means. The hydrophobicity of the coal surface has been increased sufficiently to reduce the tendency for swelling and water uptake. This together with densification has allowed the solids content to be progressively improved from 25% solids with raw coal to 65% solids with modified coals. Both raw brown coal and modified brown coal suspensions show shear thinning behaviour resulting in lower viscosities at higher flow rates. All coal suspensions displayed a yield stress once sufficient solids concentration was achieved. This yield stress can be used in the prevention of solids settling. Under simple shear mixing the network structure that provides the yield stress quickly breaks down to a low viscosity fluid with reduced yield stress and a pumpable consistency. The time necessary for structural recovery is in the order of days permitting shut-down and start-up of fuel delivery systems.

Jan 1, 1987

By Mingming Zhang, Marshall S. Coe, Marcelo W. Andrade

To supply iron units and flux burden in blast furnaces, sinter basicity is one of the vital parameters for sinter plants. The sinter basicity also plays an important role in sinter quality since it imparts the formation of different mineral phases in sinter. Pot-grate sintering tests were carried out with low and high basicity to investigate the effects of sinter basicity on sinter mineralogy, properties and productivity. It was found that with an increase in sinter basicity, both sinter productivity and reducibility (RI) increased. Tumbler index (TI) and low temperature degradation index (LTD) of high basicity sinter were comparable to low basicity sinter. Softening and melting tests showed that sinter with 3.5 C/S basicity had slightly higher softening temperature comparing to lower basicity sinter with C/S 2.6, acid and fluxed pellets. XRD analyses confirmed the formation of silico-ferrite of calcium and alumina (SFCA) and calcium ferrite (CF) in the tested sinter samples.

Jan 1, 2015

By D. B. Hobbs, L. W. Kempf, R. S. Archer

SILICON is one of the most important elements in the metallurgy of aluminum. It is always present in small amounts in the ordinary grades of "pure" aluminum, and hence in all alloys made therefrom. Within the last few years binary alloys containing up to 13 per cent. of silicon have come into extensive use for castings. Silicon is also added, beyond the amount present as an impurity, in alloys containing one or more other elements such as copper, manganese, magnesium and nickel. The binary aluminum-silicon alloys are not yet heat treated to any extent in commercial practice, although, as will be shown, their properties are affected to a very considerable degree by heat treatment. There are other aluminum alloys that develop higher strength, but the special characteristics of the silicon alloys may well lead to the application of heat-treating processes on a commercial scale. The role of silicon in the heat treatment of aluminum alloys is more important than would be indicated by consideration of the binary alloys alone, because many of the alloys that are heat treated in regular commercial practice contain some silicon in addition to that derived from the aluminum ingot as an impurity. Among these may be mentioned the heat-treated 195 alloy castings, and the wrought alloys 25S, Special 17S and 51S of the Aluminum Co. of America, and the German wrought alloy, Lautal. It is the purpose of this paper to present the results of experimental work and the conclusions derived therefrom regarding the heat treatment of the binary aluminum-silicon alloys. The products heat treated included forgings, chill castings and both "normal" and "modified" sand castings. REVIEW OF LITERATURE The literature on the heat treatment of aluminum-silicon alloys is not very extensive. The following review gives the principal references of which the authors are aware, in which appreciable information may be found.

Jan 1, 1928

By R. W. Bartlett

I first met Milton Wadsworth in 1951 as an eighteen year old junior taking his mineral processing course at the University of Utah. He guided my senior thesis, evaluating the then new polymer flocculants on settling uranium leached ore pulps. This was before ion exchange and solvent extraction. After my military service and a brief working stint at Kennecott he supervised my PhD work. He encouraged me to be active in AIME and its constituent societies, where both of us have been directors of AIME and presidents of TMS. He has been a consultant for research groups that I have managed. Above all, he has been my mentor and friend for nearly 45 years. Thus, I am honored and particularly pleased to receive 5MB's Wadsworth Award.

Jan 1, 1996

By Osorio J. D C, McMahon M. D

Burwood Beach Sewage Ocean Outfall is being constructed by the Hunter District Water Board as part of an amplification scheme to eliminate pollution from adjacent bathing beaches. The outfall consists of a 93m vertical shaft, 1950m of 2.7m diameter tunnel with a series of diffuser outlets connecting the seaward end of the tunnel to the sea floor on a rock outcrop. The site of the work is in the Newcastle Coal Measures and the project is complicated by the proximity of colliery workings to tunnel alignment, although the colliery records provided valuable information on geological features. The location of the tunnel was determined to be in the Waratah Sandstone Formation immediately below the colliery workings after three different alternatives were considered. The shaft, which will be sized to suit contractor's construction methods and equipment, will be sunk through about 24.5m of alluvial material and 68.5m of rock. The tender documents were developed to allow the contractor considerable flexibility in construction method to suit available equipment. The specification also allowed great flexibility in tunnel construction method with minimum cross sectional area of 5.7m2 being the basis for a number of allowable alternative profiles ranging from circular to horseshoe.

Jan 1, 1987

By Samuel Hoyt

THE writer has long been interested in seeking an explanation of the upper heat effect in the copper-tin alloys over the a + ß range, first described in 1913. These notes are offered, not at all as the final explanation of this heat effect, but rather to indicate certain progress which has been made toward establishing what happens over this temperature interval. While working on the thermal analysis of the copper-rich kalchoids (copper-tin-zinc alloys), it was noted that those alloys containing major portions of tin and minor portions of zinc exhibited two marked heat effects, one at about 520° C. and the other at about 600° C., instead of the single effect which is generally observed in either of the two binary series. This matter was discussed with Dr. Guertler, who suggested that a heat effect at about 600° C. in the pure copper-tin alloys might be expected. This led to a more searching examination of the thermal critical points in the pure copper-tin alloys, with the result that a marked, although somewhat weak, heat effect was located at about 600°. Somewhat later, this upper heat effect was discussed with Dr. Burgess, and it was requested that the Bureau of Standards make heating and cooling curves of one of these alloys for the purpose of removing any possible doubt as to the actual presence of the heat effect. Results obtained by the Bureau are given in Plate I. In an earlier paper1 differential curves were published showing that the heat effect occurred at constant temperature over the a + ß range and increased in magnitude with the amount of a up to a point somewhat above 20 per cent. tin. No heat effect was noticed at this temperature in the eutectoid alloy. The existence of this heat effect seems to require a modification of the present copper-tin diagram in the a + ß field, and it has been the object of the work here presented to secure the evidence upon which such a change should be based.

Jan 12, 1918