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CONTENTS PAGE Rae, Colin C.-A Possible Origin of Oil. Discussed by S. Linker, Colin C. Rae... 2 Cottingham, Kenneth.-Subsurface Conditions on Portion of Arches Fork Anticline. Discussed by David B. Reger 6 Moyer, W. Irwin.-Time to Pay Out as a Basis for Valuation of Oil Properties. Discussed by H. J. Smith 9 Pogue, Joseph E.-Future Demands on Oil Industry of United States. Discussed by James O. Lewis 11 J. J. Walsh.-Coa-lmine Ventilation. Discussed by W. B. Daly, J. J. Walsh, R. R. Sayers, H. H. Stock, George S. Rice, James W. Paul, D. Harrington, T. D. Thomas 15 Longyear, Robert Davis.-Diamond-drill Sampling Methods. Discussed by Ira B. Joralemon, J. J. Rutledge, E. C. Harder 19 Joralemon, Ira B.-Sampling and Estimating Disseminated Copper Deposits. Discussed by J. Parke Channing, John E. Hodge, E.E. Hunner, B. B. Gottsberger, W. Y. Westervelt, W. O. Hotchkiss 20 Boericke, W. F.-Sampling and Estimating Zinc and Lead Orebodies in Mississippi Valley. Discussed by J. Parke Channing, Arthur Thacher 24 Daly, W. B. and Linforth, F. A.-Organization of Mine Sampling at Anaconda. Discussed by George A. Packard, W. B. Daly, B. B. Gottsberger 25 Norris, E. M. and Rahilly, H. J.-Mine Fires. Discussed by R. Dawson Hall, W. B. Daly, Frank Haas, D. Harrington, Robert E. Tally 26 Raymond, R. M.-Safety Practice for Hoisting Ropes. Discussed by B. F. Tillson, Graham Bright, Rudolph Kudlich, J. F. Howe, Robert Peele, H. G. Davis. 30 Howe, J. F.-Use of Wire Rope in Mining Operations. Discussed by Horace F. Lunt, J. F. Howe, B. F. Tillson 36 Tanner, W. N., and Jaccard, F. C.-Wire Rope and Safety in Hoisting at Butte Mines. Discussed by Horace F. Lunt, W. B. Daly, C. L. Colburn, William Kelly, Robert Peele, B. F. Tillson, Graham Bright, Charles E. Locke 38 Richardson, A. S.-Ventilation of Butte Mines of Anaconda Copper Mining Co. Discussed by D. Harrington, Chas. A. Mitke 42 Stuart, Charles E.-Storage-battery Locomotive as Applied to Mine Haulage. Discussed by Howard N. Eavenson, Charles E. Stuart, William Kelly, Arthur Thacher, W. H. Patton, Graham Bright 45 Woodward, C. D.-Electric Haulage Systems in Butte Mines. Discussed by William Kelly, Graham Bright, Howard N. Eavenson, C. E. Arnold, Gerard B. Rosenblatt, K. A. Pauly 47 Harrington, D.-Efficient Ventilation of Metal Mines. Discussed by R. E. Simpson 52 Otagawa, Masayuki.-Mining Methods at the Ashio Copper Mine. Discussed by Horace V. Winchell, D. W. Brunton 52 Stoek, H. H. and Clagett, Thomas H.-Coal Mining Methods. Discussed by P. D. Browning, G. L. Cox, Erskine Ramsay, Frank Haas, George S. Rice.

Jan 6, 1922

By George J. Bancroft

It is unnecessary to repeat here the contents of many valuable contributions to this subject which have appeared in the Dansactions and in the publications of the U. S. Geological Survey. As a basis for the further suggestions of this paper, the following are the most important: 1. The investigation of J. R. Don,' showing the gold of certain Australasian veins to have been deposited by ascending solutions, and not by lateral secretion. 2. The theory of Prof. Posepny? distinguishing the vadose from the deep circulation, and ascribing the origin of certain classes of ore-deposits to ascending solutions of the latter class. 3. The theory of Prof. Van Hise,3 as to the underground circulation and the primary enrichment of veins thereby. 4. The paper of Prof. J. F. Kemp,4 showing that ore-deposits are largely the products of " expiring vulcanism." Many. of Prof. Kemp's ideas have been widely adopted by mining men. 5. The theory of secondary enrichment, so lucidly expounded by Mr. S. F. Emmons.V his theory, dealing with the rearrangement of ore-bodies after primary mineralization, has been generally adopted, and seems to me to have been as completely proved as the nature of the case permits. There are two facts which I think should be constantly borne in mind in formulating a theory of the genesis of ore-

Jan 1, 1908

By C. D. Hebert, M. R. King

The 56,000' (17 km) long San Vicente Aqueduct Pipeline tunnel is being constructed using precast concrete rings to act as preliminary ground support through two sections of the bored tunnel with lengths of 9,450' (2.9 km) and 33,700' (10.27 km).The six segment bolted trapezoidal ring was manufactured using a combination of steel fiber reinforced concrete and self compacting concrete in vertical moulds. This paper briefly describes the design and function of the segments, and reviews the development stages of the concrete mix, and the advantages and disadvantages of the adopted manufacturing method.

Jan 1, 2007

By J. D. Patsey, G. T. Lineberry

Introduction A computer program was developed for analyzing drum-type hoists before modifying an existing system or designing a new one. Its use permits the preliminary evaluation of a system before seeking technical assistance from mine hoist designers and manufacturers. The user-friendly program accepts a variety of data and analyzes hoisting systems for any balance state. The program can be used to calculate skip capacity to yield a desired production rate, solve for drum face width, select a permissible wire rope, estimate total horsepower of the hoist plant, and estimate annual power cost. Whether required for a large mining complex or for a relatively small operation, a hoisting system must be carefully designed to ensure the efficient, reliable, and safe flow of material. Because shaft sinking and hoist installation can total between 2.5% and 3% of the cost of opening a deep mine, proper hoist selection is critical. Today's mining engineer has at his disposal the most powerful design and analytical aid ever, the microcomputer. There is, unfortunately, limited software for the study of hoisting systems, unlike that for other materials handling equipment (Manula and Albert, 1980; Prelaz et al., 1964; Bucklen, 1969; Thompson, 1985). HOIST reduces a time-consuming set of calculations to a concise package of interrelated subprograms. A literature review revealed no common-user programs to analyze hoisting systems, although at least four major hoist designers/manufacturers/installers have their own in-house programs. To provide a tool with which the mining engineer could preliminarily analyze a materials hoisting system or could check the calculations of a hoist contractor, a computer program was developed. HOIST was written in BASIC for the IBM-PC for ease of program adaptation and to encourage field use on compatible systems. Details of program development are omitted, since the basic principles of hoisting analyses are relatively straightforward, simple, and readily accepted (Harmon, 1973; Nordberg, n.d.; Adler, 1957). Program features, intended usage, and benefits of the computerized solution are emphasized over theory development and mathematical rigor. Background The mine hoist system that is selected and installed at a mine is the "lifeline" of that mine, with installations lasting 20 years or more. Thorough study is warranted to ensure that productivity demands are met at a minimum cost per ton. The increased cost of a large, powerful, high-speed hoist must be offset by increased production to justify its selection. To optimize this tradeoff, an extensive hoisting analysis should be performed. The analyses to properly size the skip (or cage), the drum, and the hoist drive are conducive to computerization, permitting rapid evaluation of changeable operating and design parameters, such as velocity, acceleration, state of balance, and productivity demand. The program is particularly useful in conducting sensitivity trials, such as investigation into the effect of change of productivity on skip capacity and on horsepower of the hoist drive. HOIST is currently limited to the study of drum-type hoists with cylindrical drum(s). However, only minor changes to the program would permit analysis of friction hoists and conical drum configurations. Model development and testing The program is based on accepted equations and physical relationships. Examples of manual calculations formed the basis for decision points and program branching. Data is input in the order that it would be needed if the problems were solved manually. The choices are arranged likewise. HOIST was developed in sections, with manual solutions performed to check program logic. The testing became more rigorous as sections were completed. Output from one section becomes input for following sections, as appropriate. The simplified flow diagram of HOIST is given in Fig. 1.

Jan 2, 1987

By Pengfu Tan

NiModel, a thermodynamic model, database and computer program, has been developed to predict the distribution behavior of Ni, Cu, Co, Fe, S, O, As, Sb and Bi, and heat balance in the nickel pyrometallurgical processes such as Outokumpu flash smelting, Outokumpu direct high-grade matte smelting, INCO flash smelting, and Peirce-Smith converting processes. In this model, as much as 16 elements (Ni, Cu, Co, Fe, As, Sb, Bi, S, O, Al, Ca, Mg, Si, N, C and H) are considered. The compositions of matte, slag and gaseous phases, and heat balance are calculated using the thermodynamic data and the activity coefficients of the components derived from the experimental data. The model predictions were compared with the known industrial data from Kalgoorlie Nickel Smelter in Australia, Outokumpu Harjavalta Nickel Smelter in Finland and INCO Metals Company in Canada, and an excellent agreement was obtained. In this paper, the applications of NiModel in the nickel pyrometallurgical industries have been presented. NiModel has been used by Jinchuan Group Limited in China.

Jan 1, 2004

By M. Syamujulu

In 1994, Nkana smelter commissioned a multimillion US Dollar Chilean Teniente converter (CT) in its operations in order to improve its smelting technological base. The main objective was to reduce the overall smelting energy costs and increase the sulphur capture for sulphuric acid production to support the company?s leaching operations at Nchanga tailings leach plant. A decade of CT operations have since ensued following its installation and start-up. This paper provides a technical and operational audit of the performance of the CT in the first 10 years of its operations at Nkana smelter.

Jan 1, 2005

By Robert T. MacMillan

An essentially chemical technique has been developed on a small scale for the efficient utilization of certain domestic titaniferous iron ores. Three main steps are involved: (1) Sintering the ore at 1,050° C. with carbon and soda ash to reduce the iron to metal powder, retaining the titania in the slag, (2) separating the powdered iron from the slag, after wet grinding, by magnetic or gravity methods, and (3) sulfuric-acid decomposition of the titania fraction to produce pigment and certain byproducts. The technique was first applied to the tailings from the Bureau of Mines bauxite-concentrating plant at Bauxite, Ark. A good grade of powdered iron was produced from this material. Subsequently, the work was diverted to the study of the titaniferous magnetite from the MacIntyre Mine at Tahawus, N.Y., because of the potentially higher recoveries of iron, titanium and vanadium. Ninety percent of the iron in this ore has been recovered as an iron powder analyzing 90 percent metallic iron and containing 2 to 3 percent TiO2. The remaining titania was found in the slag and was recovered as pigment-grade TiO2 by application of a suitable technique. The vanadium was distributed between the TiO2 fraction and the alkaline liquor resulting from the wet-grinding and magnetic-separation operations, with only a minor proportion retained by the metallic iron.

Jan 1, 1950

By William C. Martin

"Consolidated Sudbury Basin Mines Limited owns two mines, 4 miles apart, near the southwest end of Sudbury Basin. The Errington mine lies close to the north boundary of Creighton Township and about 18 miles by car from Sudbury. The Vermilion Lake mine is in Fairbank Township, on the south side of Vermilion Lake.The first discovery of base-metal mineralization within Sudbury basin was made by James Stobie in 1897 at Stobie Falls on the Vermilion River, half a mile west of the Errington mine. A few years later Alphonse Oilier made a discovery of massive pyrite with base-metal sulphides near the west end of the present Errington workings.No work of consequence was done on these discoveries until 1924, when Joseph Errington acquired options on a large acreage of ground which was later taken over by the Treadwell Yukon Company Limited. After considerable diamond drilling this company sank No. 1 shaft in 1926. In the next three years, a large amount of underground development was done, a pilot mill was constructed and operated for two years. All operations ceased in 1931 with the fall in metal prices. While in operation the pilot mill treated 186,172 tons of ore the average grade of which was 1·07 per cent copper; 1 10 per cent lead; 4·60 per cent zinc; 0·03 ounces gold; and 1 70 ounces silver.Up to the time of closing in 193 l there had been completed at the mine 26, 790 feet of lateral work and 75,500 feet of surface and underground diamond drilling. The company records, however, showed no figures on ore reserves, except broken ore in stopes amounting to about 60,000 tons. A study of the plans, prior to reopening the mine in 1952, showed 1,450 lineal feet of ore (at 1952 prices) opened up by drifting on the 300-foot and 500- foot levels. It is clear that no comprehensive picture of the structure was had at this time. The orebodies were considered to be very irregular pods scattered through masses of quartzite-carbonate in a sheared zone about 800 feet wide. In some way the ore was believed to be related to the tuff-slate contact zone. With this picture it was impossible to make a reasonable ore estimate or even gauge the tonnage potentialities with any feeling of reliability."

Jan 1, 1949

By Jerold Bishop, Grant Bearss, Aleksey Egorov

"When a shock wave is released in the bottom of a drill hole filled with wet concrete slurry, the result is called an electrohydrodynamic effect, or EHDE. The energy is carried through the fluid with minimal loss because the slurry is an incompressible medium. Repetitive discharges provide a series of energy pulses that compact the soil along the pile shaft and at its base. The process is analogous to repeated applications of low-energy blast densification or to dynamic compaction. In general, the process is not depth dependent. EHDE was identified in the 18th century by an American scientist who observed that a spark between two electrodes placed under water induced a burst of pressure. In 1957, two Russian engineers formulated a process and received a patent for a method of creating a pressure wave by transforming power from an electrical discharge to a mechanical impact. They derived more than 200 applications for technical and industrial processes.In the 1970s, civil engineers at the Engineering and Building Institute in St. Petersburg, Russia, began to look at EHDE to improve the capacity of drilled piles. Early experiments showed that electric discharges in a wet concrete slurry mix could create a pressure wave of up to 26 MPa (3700 psi). Later tests demonstrated that this pressure level could be created in a drilled pile hole. The researchers devised equipment and in the early 1990s began to study pulse technology as applied to drilled piles.This application was accepted into the Russian Federation Building Code in the 1990s. The code treats “regular” drilled piles with equivalent bearing area as having roughly half the capacity of a driven pile. However, the code considers drilled piles treated with the EHDE technique a direct “one for one” substitution for driven piles and allows higher values if the capacity is established by static load testing. Hundreds of projects have been completed in Russia using this technology to value engineer drilled pile projects. In several instances, the number of drilled piles installed was fewer than half of the number originally planned for due to the capacity increase that EHDE-treated piles provided.Drilled PilesIn drilled pile construction, the EHDE process creates a mechanical pressure wave that impacts the base and sidewall of a drilled pile shaft. Soft, poorly consolidated or loose soil is compacted by successive pulses of pressure created by electrical discharges. These mechanical impulses are made by inserting a discharge probe into the wet concrete slurry. A discharge across the tip of the probe creates the pulse that travels outward to the sidewall and base of the drilled pile through the incompressible medium of the slurry. The power pack ratings for equipment presently in use are 35 and 50 kJ (kilojoule).Each pressure wave strikes the soil, causing compaction and expanding the hole. Workers apply the pulses until the size of the hole stops increasing. They watch the slurry level during pulsing. When the level quits dropping, further soil compaction in the drill hole sidewalls and base is not possible. After the pulse process is complete, workers insert a rebar cage and the pile is finished.The process does not alter the soil mineralogy. The electrical discharge is internally grounded and does not arc to the sidewalls of the drill hole. Soil is not scorched or altered in any manner; it is only compacted by the pressure wave. This technique has been used in urban areas with no effect on electrical or electronic equipment."

Jan 1, 2009

A system to continuously measure the concentration of radon in mine ventilating air has been developed and tested in a uranium mine. In use, the air/radon mixture to be monitored is pumped through filters into a scintillation cell where nuclear decay of the radon produces flashes of light. These are electronically counted, giving a quantitative measure of the radon present. Air is continuously drawn from the mine atmosphere into the radon sensor box. This air sample passes through two filters into the detector cell as shown in the schematic diagram. A portion of the radon in the detector cell will experience nuclear decay, producing polomium 218 and an alpha particle. The alpha particles from the fraction that decays strike a zinc-sulfide coating on the inside wall of the cell and produce flashes of light. These enter a photo-multiplier tube which records each flash as an electrical pulse. An amplifier increases the voltage of each pulse, allowing electronic screening to remove noise and other undesirable pulses. The remaining pulses are counted by a conventional data acquisition system.

Jan 1, 1978

By José María Lezcano, Diego Urquiaga, Pedro Delvasto, Marcos Garayar

La extracción de minerales ricos en sulfuros metálicos tiene el inconveniente de generar drenajes ácidos (AMD), los cuales causan severos impactos en los ecosistemas acuáticos, el suelo y el recurso hídrico. Como posibilidad de remediación (alcalinización) de estos pasivos, en el presente trabajo se propone el uso de coproductos férricos oxidados (CFO). Luego de presentar las características de un tipo de CFO específico, se muestran los resultados —a escala de laboratorio—sobre la respuesta alcalina del mismo, y se discuten las implicancias de estos hallazgos para el tratamiento de los AMD.

Nov 30, 2020

By Richard P. Rothwell

In January last I published in the Engineering and Mining Journal a table giving, with a considerable degree of accuracy, the production of anthracite coal for the year 1874. At that time it mas impossible to give any correct estimate of the production of bituminous coal, for the returns I had been able to secure from such distant and scattered districts were not always forwarded punctually, and the work of .obtaining anything like a true estimate of the coal mined in districts from which I was unable to obtain official returns was both laborious and tedious. As will be seen from the detailed reports furnished herewith, I have succeeded in obtaining tolerably accurate returns of 20,093,704 tons; and upon careful revision by numerous well-informed local authorities, my first estimate of the amount of coal not officially returned to me has grown very considerably; indeed, as I get more information on the subject I find that our bituminous coal production greatly exceeds the amount we have been accustomed to hear it placed at, aggregating as it does, 26,465,704 tons. Mr. Andrew Roy, State Inspector of Mines for Ohio, has reported the production of Ohio at 4,168,445 tons, while his first estimates were but 3,820,000 tons; and similarly, in other cases, the more full the returns direct from the mines the more incorrect do I find all previous reports. I am able now to furnish, not an accurate statement, indeed, but by far the most full and reliable one that has yet been published of our coal production. The amount of labor involved in obtaining this admittedly imperfect report has been simply enormous. In the following tabular statement it will be perceived that Pennsylvania produces nearly one-half of all the bituminous coal mined

By Diego Pacheco Wermuth

O presente trabalho apresenta os resultados do estudo e aproveitamento de cinzas leves da queima de carvão mineral em termelétrica, como reforço para o Compósito de Matriz Metálica de cobre. Foram estudados diferentes percentuais de cinzas leves como reforço para o cobre, sendo misturados estes pós através de misturador “duplo v”, compactando os pós em diferentes pressões e sinterizando os corpos de prova obtidos pela compactação. A amostra sinterizada que apresentou a maior dureza entre todos os corpos de prova sinterizados, atingindo 89 HV, foi utilizada como base para a formulação e obtenção de novos corpos de prova, que foram estudados sob condições de moagem dos pós por moinho de bolas e moagem de alta energia. A fabricação do compósito seguiu os padrões industriais do processo de Metalurgia do Pó, como a mistura e moagem dos pós, compactação dos pós e sinterização em atmosfera controlada. Foi realizado o estudo das propriedades mecânicas do compósito formado por cobre e cinzas leves, que comprovou o aumento da dureza para 122 HV. Este trabalho proporciona uma nova aplicação para as cinzas leves, utilizando estes resíduos de usinas termoelétricas como matéria prima para reforço mecânico na composição de peças à base de cobre na indústria metalúrgica.

Aug 17, 2017

By E. O. Mixon, Jack D. Kennedy

INTRODUCTION This contract is the most northerly portion of the Metropolitan Sanitary District of Greater Chicago's Tunnel and Reservoir Plan. (TARP) The project begins at Addison Street in Chicago and proceeds northerly approximately ten miles to end at Wilmette Harbor and Lake Michigan. The project which consists of 2 work shafts, 32 drop shafts, 7.322 km (24,020 ft.) of 6.7 m (22 ft.) diameter circular rock tunnel, 8.458 km (27,750 ft.) of 9.2 m (30 ft.) diameter circular rock tunnel and miscellaneous rock bolting and grouting, was bid for a total cost of $63,140,480. The tunnel invert elevation varies from 65.5 m (215 ft.) to 77.4 m (254 ft.) below the ground surface, which places the tunnel in a rock formation of dolomite limestone. At the tunnel invert, the unconfined compressive strength of the limestone varies from 96 MPa (14,000 psi) to 152 MPa (22,000 psi). The 6.7 (22 ft.) diameter tunnel required the mining of 10.9 cu m. (14.2 cu yd.) of rock per lineal foot of tunnel while the 9.2 m (30 ft.) diameter tunnel required the mining of 20.1 cu m (26.3 cu yd.) of rock per lineal foot of tunnel. The total cubic meters of rock required to be excavated from both tunnels was 818,821 cu m (1,070,978 cu yd.). All of this will be mined by tunnel boring machines (TBM). These tunnels were not to be lined with concrete. The thirty two drop shafts have upper portions that are cylindrical in the overburden and rock sections. They were divided into two groups, depending on diameter, with a different construction method for each group. The first group consisted of twenty three of the

Jan 1, 1979

By K. Pathak

Loaders and dump trucks are the most commonly used surface-mining equipment. Negligence of the safety-engineering aspects of dump trucks may result in serious accidents in a mine. A reduction in the risk of an accident due to the deployment of trucks can he achieved by engineering analysis, risks assessment, improved safety features, active safety devices, condition-based maintenance, in-built protection systems, etc. This paper presents some cases of accidents in Indian surface coal mines and advocates a systems approach to safety.

Jan 1, 1999

By J Seccatore, G Sadao, M Cardu, G De Tomi, L Finoti, F Galvão, J Romero Huerta, A Rezende, J Bettencourt

In the mining industry, rock blasting can be considered as the first phase of comminution. The downstream phases of comminution are mechanical, and consist in consecutive stages of crushing and milling for grain size reduction. The total energy of mechanical comminution depends on grain size and on the resistance of the material to grindability. Usually, the first is quantified by the grain size distribution or one of its KPIs (such as the diameters X50 or X80), while the latter by the working index (WI), representing the amount of energy necessary to reduce the size of grains of a determined amount of material to the desired equivalent diameter (usually expressed in kilowatt hours per tonne – kWh/t). It is widely recognised that it is possible to manage the output of a blast in terms of grain size distribution varying specific charge (powder factor – PF) and charge distribution; specific algorithms such as the KUZ-RAM or the SWEBREC have been created to predict such output. It has also been demonstrated how higher PFs weaken the blasted material by creating micro-fractures that reduce its WI. This paper focuses on a related aspect: the influence of charge distribution on the specific comminution energy in crushing and milling. Small-scale blasts have been performed on 14 marble blocks with different PFs and charge distribution. For every PF, charges have been designed to simulate concentrated and distributed geometries. Concentrated charges simulate opencast blasts with large-diameter holes, with large burdens and spacings. Distributed charges simulate bench blasts with small-diameter holes and reduced burden and spacing. Three control blocks have been fragmented by mechanical means for comparison. For every sample the grain size distribution and the WI in ball mill has been determined. Results show the correlations between charge distributions and the specific energy of mechanical comminution in milling. Finally, the opportunity of adjusting charge diameters and distributions in opencast blasts to improve the output of the comminution circuits is discussed.CITATION:Seccatore, J, Romero Huerta, J, Sadao, G, Cardu, M, Galvão, F, Finoti, L, Rezende, A, Bettencourt, J and De Tomi, G, 2015. The influence of charge distribution on the grindability of the blasted material, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 749–754 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Guy A. Johnson

To improve productivity and cut costs, modern underground mining operations have become more mechanized. This mechanization has increased the usage of fuels, hydraulics, and electrical equipment associated with diesel-powered vehicles, thereby also increasing the hazards of underground mine fires. The Bureau of Mines evaluated the fire hazard problem and assembled prototype components for a system that would automatically sense and extinguish fires on mobile underground equipment. The prototype system and alternative designs were in-mine-tested and proved effective. This report summarizes this technology, which can cost effectively help solve the problem of fire hazards on underground vehicles.

Jan 1, 1983

By Shawna Munn, Nadir Ansari, Toben Jerry

With ever increasing demands on space in urban environments and smaller available footprints, buildings are being designed to increasing heights to meet the need. This case study discusses the increasing challenges in developing projects within urban environments with smaller available footprints and increasing building heights. The One, Canada’s tallest residential building under construction will stand at 85 storeys and is located at one of the most prominent and built up intersections in Toronto, Yonge Street and Bloor Street. This led to many challenges in design and construction of the shoring and foundation work, including the required design capacity of the foundations for the supertall building and proximity of the large diameter drilled shafts to the excavation shoring wall. This case history describes the shoring design option evaluation, performance, and lessons learned to date throughout construction of the building foundations within a small congested site. PROJECT OVERVIEW The One, Canada’s tallest residential building under construction by Mizrahi Developments, is a supertall building that will stand at 85 storeys and 306 m (1005 ft). The first 18 floors will be comprised of retail, restaurants, and hotel with luxury residential condominium units in the tower above. The project is located on the Southwest corner of Yonge Street and Bloor Street, one of the most prominent and built up intersections in Toronto. The L-shaped excavation measures 58 m by 47 m (190 ft to 154 ft) and ranges from 22 m to 28 m (72 ft to 92 ft) in depth with one internal corner projecting 11 m (36 ft) into the site.

Jan 1, 2019

By A. F. Matheson

The St. John Del Rey Mining Company, Limited, is an English company owning 150 square miles -of mining lands near Belo Horizonte, Minas Geraes, Brazil. The area is 2,300 to 5,000 feet above sea level, with a pleasant and healthy climate. Bedrock is Precambrian. The Nova Lima series of metamorphosed sediments and some volcanics is overlain uncomfortably by the Minas series of quartzites, itabirites. etc. Batholithic granite and gneiss cut both series and basic dykes cut all these rocks. There are important deposits of gold, iron, and manganese on the Company's holdings, as well as occurrences of arsenic, antimony, cobalt, nickel, dolomite, day, quartz, -ochre, bauxite, kyanite, and asbestos. Except for gold and consequent recovery of arsenic, all the other materials are relatively unexploited. The Company operates the Morro Velho gold mine and the Espirito Santo and Raposos gold mine. The Morro Velho mine was purchased in 1834 for £56,000. To the end of 1952 it had produced 7,000,000 troy ounces of gold from 15,000,000 short tons of ore. The ore z?ones are replacement deposits in a sinuous siliceous dolomitic rock locally termed "lapa seca," and plunge east, near surface at 45 °, at 8,000 feet at 15°. The ore minerals are pyrrhotite, arsenopyrite, pyrite, and chalcopyrite. Gold is finely distributed and almost nowhere visible. Ore reserves at the end of 1952 were estimated at 5.5 million short tons grading 0.39 oz. gold per ton. Chances exist for new ore within the mine area. The Espirito Santo and Reposos mine, in folded banded iron formation, has mineralization similar to Morro Velho but sulphides are less abundant. The mine to a depth of 2,500 feet has estimated ore reserves of 1.5 million tons of an average grade of 0.28 oz. gold per ton. New ore may be expected both laterally and at depth. To the end -of 1952, the ?Company had paid dividends of almost £4,- 600,000, largely earned from the operation of the gold mines.

Jan 1, 1956

By R. R. Wells, K. C. Vincent, A. O. Ipsen

"INTRODUCTION The Philipsburg Mining District, Granite County, Mont., has been the largest producing area for battery-grade manganese (70 percent MnO2) in the United States since the First World War. Two companies, the Trout Mining Division of the American. Machine & Meals Co., and the Moorlight Mining Co., have intermittently mined and milled 120 to 250 tons of 25-percent manganese ore per day for the production of concentrates of this grade.Investigation of the district by engineers of the Federal Geological Survey and Bureau of Mines indicated that further exploration and develop¬ment would make available additional oxide and carbonate manganese ores for milling and production of metallurgical-grade manganese. If the battery-grade producers converted their plants to the production of metallurgical-grade concentrates, their production also could be increased through greater recoveries.Until February 1, 1944, the Metals Reserve Company, through its agent, the Sunshine Mining Co., purchased milling-grade manganese oxide and carbonate are for stock-piling at Philipsburg. After that time, only carbonate ore was purchased. Based upon the assumption that the stock pile was a true cross-section sample of the producing area, metallurgical studies were made on representative samples from the Metals Reserve stock piles. Testing also was conducted on two other samples of Philipsburg oxide manganese ore obtained by engineers of the Bureau of Mines from the Little Dandy claim of the Donlan group and from the Marie mine. All ore samples tested were found to be amenable to concentration by ore-dressing methods for the production of concentrates that when sintered met Metals Reserve Company specifications for metallurgical-grade manganese."

Nov 1, 1947