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By L. L. Wyman

IN order to clarify and amplify the existing data concerning the action of the cementing material in cemented tungsten carbide alloys, the authors have initiated this investigation of the entire range of cobalt-tungsten carbide alloys. Inasmuch as the ultimate objective is relative to what actually goes on during the sintering of cemented tungsten carbide materials, this work was necessarily restricted to heat treatments similar to those used in actual production of these materials. In the course of numerous experiments, the authors have noted several conditions that indicated that there was a solubility to be considered. Among these factors are the following: 1. Many of the alloys showed a much larger amount of binding constituent to be present than could possibly be accounted for by the cobalt content. 2. In many areas, grains of the carbide constituent are much larger than the particles of carbide originally added. In addition, these grains are of very regular contour. 2a. In samples of cemented tungsten carbide which had been fused in the atomic hydrogen torch in the presence of excess hinder constituent, immense grains are formed, and their shapes are very regular. This is also true when the cemented tungsten carbide of 13 per cent. Co content is fused alone in the atomic hydrogen torch. Contrary to general expectation, chemical analysis of this material, after fusion in the atomic hydrogen torch, checks the analysis of unfused material. 3. In making the cemented tungsten carbide materials by the process of exerting the pressure at the time of heating a certain portion of the contents squeezed out of the mold. Chemical analysis has shown that this material contains approximately 12 to 20 per cent. of tungsten. The microstructure shows a cored dendritic structure interlaced with eutectic network, and some graphite, as shown in Fig. 1. 4. Thermal analysis of these materials has consistently indicated an arrest point close to 1350° C.

Jan 1, 1930

By Adrian E. Ross

DRILLING through caving formations in diamond drill holes at depths greater than 2000 ft has long been a serious problem. These caving formations are normally passed only by casing the hole or by cementing the hole. Casing the hole is possible only when a resulting smaller hole is acceptable. In as much as only a limited number of reductions are economically practical, cementing is frequently considered the only method suitable for solving these problems. Cementing either by pumping a slurry into the hole or by dropping cylinders containing cement has proved satisfactory on holes under 2000 ft. In holes substantially deeper than 2000 ft these methods are not satisfactory, since during the pumping process cement separates out, whereas cylinders usually break before the bottom of the hole is reached. A new procedure, the injector method, apparently solves these problems.* With this method, cement is lowered in the hole in a cylinder, the cement being

Jan 1, 1952

Oxidation or sulphidization of the surface of pyrrhotIte partIcles enhances atomic interdiffusion at elevated temperatures and provides a mechanism for interface growth between particles in contact. In a mass of pyrrhotite-rich ore or tailing, where oxidation heating is not controlled, bonding of particles by diffusional mass transport contributes significantly to the agglomeration of the mass.

Jan 1, 1976

By I. N. Knapp

Foreword I HEREWITH present some notes on the use of Portland cement to cement in the casing, and for plugging, to exclude water from oil and gas wells, and the methods employed. I have used my best efforts to make each step of the operation of cementing wells perfectly clear. The information is the result of actual experience and observation. The illustrations are from original drawings made especially for this paper. Portland Cement It is not necessary to discuss here the manufacture of cement. Any established brand of the slower setting Portland cements may be purchased with the confidence that it will harden, if properly used, and exclude water from and plug wells efficiently. Setting.-By the setting of cement is meant its initial change from a soft or plastic mortar to a friable solid. After the cement has become thoroughly set it is still very weak and can be readily pulverized in the fingers. Setting is thought to be effected by the crystallizing out of the silicate and the aluminate of lime, which are soluble in water in their anhydrous form. After dissolving in the water they pass to the hydrated state, in which they are insoluble, and hence are precipitated in a crystalline form.

Jan 3, 1914

By Charles George, Ronald Faul

The cementing process has been used in approximately 2.5 million oil and gas wells to seal, protect and isolate various downhole formations against communication. It has been adapted to other more specialized situations such as solution mining and sealing salt storage reservoirs. The technical literature contains very few papers specifically dealing with the cementing process for these applications, yet there have been many special projects in various parts of the world that are novel. These will be highlighted in this review. This paper also presents a comprehensive review of the various techniques used in cementing wells drilled for the recovery of soluble salts and brines. It also covers the application of cementing techniques to a large number of wells drilled for the storage of hydrocarbons in South Louisiana.

Jan 1, 1985

By T. C. Tseng

Austenitization is a critical stage in heat treatment of steels. The available kinetic data in reference to various initial microstructures are very limited, particularly at high heating rates. In this study, integrated experimental and computational approaches have been conducted to quantify the progress of austenitization and the attained microstructure. In particular, the study is concentrated on cementite and carbide dissolution in two steel grades. Various computational methods are developed to facilitate the study: (l) an algorithm for direct determination of kinetics data as well as progress of transformation from high-rate dilatometer tests; and (2) a suite of mesoscale computational models for particle dissolution, elements diffusion, mechanics, thermodynamic and the resulting kinetics of transfonnation. Critical exprimentation is carried out using advanced techniques in microstructure characterization, chemical analysis, and Gleeble thermal-mechanical simulator on specimens of well-controlled initial microstructures. Keynotes: Cementite, Carbite, Dissolution, Steels, Austenitization

Jan 1, 2003

By Khaled Morsy

Cementitious seals are made of foamed cements with strength ranging from 100 to 600 psi. These cementitious seals are usually used at locations where the seal will be subjected to some convergence, assuming that this material can absorb entry closure without compromising the structural integrity of the seal. Prior to 2006, Lake Lynn Experimental Mine (LLEM) conducted full-scale tests on various cementitious seals designed to meet or exceed the 20-psi horizontal static load requirements of the old 30 CFR1 75.335. Both hydrostatic and dynamic loading tests were conducted. The structural response (pressure and displacement readings) obtained from these tests were recorded. The stability of the cementitious seal is based on balancing the load applied to the face of the seal from the explosion against the shearing resistance at the seal/rock interface. Therefore, the properties of the seal/rock interface, such as stiffness, cohesion, friction, etc. are critical to determine the stability of a cementitious seal. These properties are usually assumed by the researchers in their models. This paper emphasizes the importance of having the correct properties of seal/rock interface in the numerical modeling. FLAC 3D models were developed to simulate Celuseal2 cementitious seals subjected to both hydrostatic and dynamic loadings. Using the hydrostatic and dynamic loading test data conducted at LLEM, the static and dynamic properties of the seal/rock interface were back calculated. The FLAC 3D models showed good agreement with the test results.

Jan 1, 2009

By Khaled Morsy

Cementitious seals are made of foamed cements with strength ranging from 100 to 600 psi. These cementitious seals are usually used at locations where the seal will be subjected to some convergence, assuming that this material can absorb entry closure without compromising the structural integrity of the seal. Prior to 2006, Lake Lynn Experimental Mine (LLEM) conducted full-scale tests on various cementitious seals designed to meet or exceed the 20-psi horizontal static load requirements of the old 30 CFR1 75.335. Both hydrostatic and dynamic loading tests were conducted. The structural response (pressure and displacement readings) obtained from these tests were recorded. The stability of the cementitious seal is based on balancing the load applied to the face of the seal from the explosion against the shearing resistance at the seal/rock interface. Therefore, the properties of the seal/rock interface, such as stiffness, cohesion, friction, etc. are critical to determine the stability of a cementitious seal. These properties are usually assumed by the researchers in their models. This paper emphasizes the importance of having the correct properties of seal/rock interface in the numerical modeling. FLAC 3D models were developed to simulate Celuseal2 cementitious seals subjected to both hydrostatic and dynamic loadings. Using the hydrostatic and dynamic loading test data conducted at LLEM, the static and dynamic properties of the seal/rock interface were back calculated. The FLAC 3D models showed good agreement with the test results.

Jan 1, 2009

Magnetite cenospheres 40-270 I/m in diameter have been found during the combustion of pyrite concentrate.Micrographs of the surface and internal structures are presented together with comment on the mechanism of forrnation.The similarity to cenospheres found during the combustion of pulverized fuel was noted and speculation raised to their contribution to the dust and fume load in flash smelters.

Jan 1, 1980

The application of modern sciences prior to nineteenseventies have resulted in the placing of Continental Drift theory into broader concept of Plate Tectonics. The concept is applied to explain the Cenozoic Tectonics of North Sumatera.Oceanic crust flooring the Indian Ocean is moving northeasterly and being obliquely subducted at a Benioff zone along the western margin of Asian Plate, marked by the Sunda Trench in the west coast of Sumatera. This phenomenon was generated since late Mesozoic, continued during Cenozoic era up to present day, resulted an exellent example of arc-trench system which can be traced along SW - NE transect of North Sumatera.The oblique-subducting plate of Indian Ocean beneath Asian Plate, together with spreading of Andaman seafloor beginning in Pliocen epoch, have led to the origin of Sumateran Fault System; the System extends throughout the length of Sumatera island. In the region under review it comprises almost contiguous set of broadly SE-trending. Evidences for transcurent-dextral displacement have been observed.

Jan 1, 1990

By Robert M. Jimeson

At the recent SME Fall Meeting in Salt Lake City, Robert M. Jimeson, Physical Science Administrator of the U.S. Bureau of Mines, cited the research programs underway in the Bureau's Division of Coal Research, and outlined their current status. These research programs have been selected by the Division because of their relative value and high probability of success in contributing to the conservation of the Nation's coal and to the expanded use of coal in current or new markets. Since about 50% of coal consumption in the United States is in the production of electric power, 20% in production of metallurgical coke, and over 20 % by industry in producing process steam and power, the Bureau has placed much emphasis on research that will maintain coal's leadership in these established areas. This emphasis is reflected in the projects discussed on these pages. Bear in mind that this survey is not all-inclusive. Other projects underway include studies on furnace performance factors, improved burner design, and other critical boiler work which can be used immediately by industry to improve efficiency of current practices in power generation; other investigations are aimed at reducing fireside deposits and corrosion of boiler and super- heater tubes, fly ash utilization, and control of SO, from flue gases (a major step in preventing air pollution). These plus many other projects during the past years have served to focus attention on the fact that the U. S. Bureau of Mines is presently making the largest single contribution to this Nation's coal research effort.

Jan 11, 1963

By AIME

Compiled by Mary Ann Gross, Department of Energy. Bruceton. PA. Supplemental data from Coal Age indicated by (*). Reprinted by permission from CoalAge magazine.

Jan 1, 1981

The proceedings of the Centenary Banquet that was held on Friday, 25 March 1994 at The Bal Room of The Carlton at 19:30 follow. Dr H. Scot-Russell The Chemical and Metallurgical Society of South Africa-a forerunner of this Institute-was founded at a meeting held in Johannesburg on the 24th of March, 1894. One of the traditions established early in the life of the Society was the Annual Dinner, which became a major event in Johannesburg's social calendar. It was always attended by people of stature in the industry and in the community, and was usually addressed by a high-ranking Government figure. We are delighted that, on this one hundredth birthday of the Institute, we have been able to continue the tradition. I welcome you, Mr State President, and your charming wife, and we look forward to hearing your address later this evening.

Jan 1, 1994

The Centenary Distinguished Lecture was held on Thursday, 24th March, 1994 at the Convention Centre of the Sandton Sun, Johannesburg at 20:00. Herewith the proceedings that followed. P.R. Janisch: The South African Institute of Mining and Metalurgy began life one hundred years ago tonight, and eight years (almost to the day) after the 1886 discovery of gold, which has impacted so profoundly on the course of events in our country since then. The Early Years That discovery was a mater of fortune, but not in the sense of the conventional prospector's lucky strike. Canny explorers, such as the Strubens, had been around for some years and, if George Harrison had not stumbled over the Main Reef when he did, someone else would surely have done so within months. The element of luck was that the gold-bearing rocks of the Witwatersrand actually lay exposed to sight. We now know that they are something of the order of 2,5 billion years old. Rocks of that age are usually covered by younger formations. In fact, the bulk of the Witwatersrand Basin is covered by lava, dolomite, and Karoo measures. What, one wonders, would our history have been had the Karoo, which stops at the Vaal, extended no more than 60 kilometres further north. Dr H. Scot-Russell A piece of advice attributed to Paul Kruger, the who was President of the South African Republic one hundred years ago, was the following: 'Seek from the past that which is good, and build on it for the future'. It is advice that can be applied universally and, whether deliberately or not, it must have motivated my predecessors when this Institute celebrated its 40th, 50th, and 75th birthdays. Those milestones were each marked by retrospectives, as Peter Janisch has so ably presented tonight on our hundredth anniversary. The parallels do not end there. We find ourselves in times no less daunting than those our predecessors. Next month will see the birth of a new kind of South Africa; so did May 1902, May 1919, and May 1948.

Jan 1, 1994

The Centenary Luncheon for Past Presidents was held on Thursday, 24 March, 1994 at The President's Room at Gold Reef City, Johannesburg at 12:30. Herewith the proceedings that followed. Dr H. Scot-Russell It is with great pleasure that my fellow Office Bearers and I welcome you, our Past Presidents, to this luncheon to mark the centenary of the SAIMM. Today one hundred years ago, a group of professionals met and agreed to draw up the constitution and by-laws of a society later to be called an Institute. The Presidents of the Institute, of course, become its Past Presidents and help to guide its progress. A number of our sister institutes cannot wait for their Past Presidents to move of their councils, and cannot understand how we can give such free reign to ours! We believe it one of our strengths. The successful cooperation between our Past Presidents and ourselves is due to the personalities of these men. They attend meetings not to ensure that the status quo is maintained, but allow the current Office Bearers freedom to lead the Institute as they think fit. But they are always present to give sound advice, a helping hand, and support to the Institute in every way.

Jan 1, 1994

The centenary of Julia Ward Howe, author of "The Battle Hymn of the Republic," is of particular interest to the members of the Institute because of the very active part that has been taken in the affairs of the Institute by her son, Dr. H. M. Howe. By an order of the Board of Education, the one hundredth anniversary of Mrs. Howe's birth, May 27, was observed in the public schools of New York City with the singing of the fatuous battle hymn. Boston, the city of her adoption, celebrated her centenary by a service in the Church of the Disciples, where Governor Coolidge made an address, and in which John Andrew Post took a prominent part. General Pershing sent a letter, which was read by the Rev. Abraham Mitrie Rihbany, in which he said: "It is a great privilege to bear witness to the widespread effect of ?The Battle Hymn of the Republic? on the morale of the fighting men. It is unique in its religious fervor and enthusiasm and whenever sung it can have but the same effect which it produced when it was first sung in the Civil War."

Jan 7, 1919

By S. Budavari

On the one-hundredth anniversary of the founding of the South African School of Mines, this paper presents a historical review of the tertiary mining education carried out by the School of Mines in Kimberley and the subsequent institutions in Johannesburg. In addition to recording and evaluating a century of mining education, it describes the current activities of the Department of Mining Engineering at the University of the Witwatersrand, which is believed to be the natural successor to the School of Mines. The comparison of earlier and contemporary academic mining activities reflects a gradual transition from the educational philosophy and objectives of a school of mines to those of a modem university department. In the conclusions, some aspects of the educational effort expended during the past hundred years are briefly highlighted.

Jan 1, 1996

"The Metropolitan St. Louis Sewer District (MSD) in Missouri, the country’s fourth largest sewer system, is upgrading its storm and wastewater infrastructure in a 23-yearlong, $4.7 billion initiative called “Project Clear.” Historically, during times of intense precipitation, the current sewer system becomes overwhelmed. The primary goals of this project are to improve water quality and to alleviate many wastewater concerns in the St. Louis region by planning, designing and building community rainscaping, system improvements and an ambitious program of maintenance and repair.Part of the system renovation has focused on constructing underground tunnels for storm water storage, permitting controlled drainage of runoff, and preventing overflows into rivers and streams. Construction plans for these storage tunnels called for eight vertical intake and ventilation shafts to be bored from the ground surface. These shafts will then be intercepted in the bedrock at a depth of about 150 ft (45.7 m) during the excavation of the 3,000 ft (915 m) long underground tunnel that will be about 28 ft (8.5 m) in diameter. According to John Deeken , a geotechnical engineer with Black & Veatch Corp. and construction manager for the Maline Creek project, the drilling and blasting technique for creating the shafts was ruled out because the project was located in a residential neighborhood. “We could have used rock coring or a cutter head, but the drop shaft for this project is constructed within 10 ft (3.05 m) of an existing 108 in (274 cm) diameter sewer main,” Deeken said. “We had to take precautions to avoid damage to it.”A primary planning mandate of all MSD Project Clear phases requires minimized impact on traffic and residents. The canister drilling method enabled work to be confined to the median of a residential boulevard running perpendicular to the side street without detouring traffic. In addition, canister drilling offered a highly-precise means to create the shafts, leaving a smooth-sided borehole, right on target. Ground conditions in this 132 in (3.35 m) diameter intake shaft were wet due to the high groundwater levels and close proximity to the Mississippi River. “They’ve been finding shale in 2 to 6 ft (0.6 to 1.8 m) layers between weathered layers of Mississippian limestone,” said Dan Spiecher, technician at Center Rock (CRI). “The 2 ft (0.6 m) layers we can punch through. The 6 ft (1.8 m) layers slow us down.”"

Jan 1, 2017

By Thomas P. Dolley

Building stone, cassiterite, kaolin, gold, lime, and peat were the only commodities mined, The country's main economy was in agriculture, primarily in coffee exports. Tribal violence occurred again, between the Hutu and Tutsi tribes, causing an estimated 50,000 deaths, mainly in rural and mining areas. The inflation and a large deficit continued. The country continued to import cement, fertilizers, oil, and petroleum products. Burundi possessed numerous small gold deposits. The northwest and north-east were the country's two most important gold-bearing regions. A large kaolin deposit was found at Ngozi, and its mining was specified in the fifth 5-year development plan for 1988-1992. In the area of Rugombo, limestone was being explored with the intention of opening a cement plant.

Jan 1, 1990

By Enrique Levy

Central America is graduating this year into large scale mining with the start up of Inco's multi-million dollar nickel laterite processing plant in Guatemala. In the other extreme of the Isthmus in Panama Texas Gulf Sulphur is doing check diamond drilling and foundation test drilling at the Cerro Colorado copper porphyry. The higher price of gold and silver has spurred development and exploration of several small precious metal mines. The purpose of this presentation is to make a brief resumé of the most important mines operating in the area and a list of significant exploration projects. Also, tables will be shown to compare mining codes and taxes. Unfortunately these tables lack information on Panama. Before starting I like to express my appreciation to Kennecott Copper who permitted the use of some of the data compiled by the author on their behalf during the year 1975. Other persons which did not want to be named also have my gratitude.

Jan 1, 1977