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By George H. Jones

NO STRANGER phenomenon exists in the American mining industry today than the so-called bootleg anthracite industry in Pennsylvania which now produces probably close to 15 per cent of the total hard coal out- put of the State. Instead of being what - was first thought to be a temporary condition, countenanced because of the desperate condition of some of the miners at the depth of the depression. it is thriving now as never before. Re- ports of it have penetrated all over the world, as exemplified by inquiries concerning it in Durban, South Africa mentioned by John C. Cosgrove in his article in the July MINING AND META LURGY.

Jan 1, 1939

By Nabil F. Ismael

The axial capacity of step tapered bored piles in sand was examined by field tests at one site in Kuwait. Two straight piles, and two step tapered piles were load tested in compression to failure. All four piles were 3 m deep. The straight piles were 0.2 m in diameter. The step tapered piles had a diameter of 0.3 m for the upper segment which extended up to 40% of the pile length changing to 0.2 m diameter for the lower section. The soil profile consists of medium to dense sand with minor cementation and no groundwater was encountered. Both the ultimate bearing capacity and the settlement at working loads were examined. The axial capacity of the step tapered piles was greater, and the settlement at working loads was less, compared with the straight shaft piles. The increase in capacity is mainly attributed to the added side friction along the larger diameter top segment of the shaft.

Jan 1, 2008

By H. P. Willard, R. W. Gates

Basic Inc., has been mining magnesite and brucite for 27 years at Gabbs, Nev. This is a medium sized open-pit mine. The magnesite deposits are in north-western Nye County about 30 miles east of Luning, Nev., on the west slope of the Paradise Range, at an elevation between 5000 and 6000 ft. The magnesite and associated brucite is used to make magnesia refractories employed principally in the steel industry and magnesium oxide for various chemical uses.

Jan 10, 1963

By D. R. Flinn

A newly developed chemical conditioning technique, which greatly simplifies the preparation of plating baths for the electrodeposition of titanium diboride (TiB2) coatings, is described in this report. The new plating technique was used to prepare samples of titanium diboride (TiB2) coatings on three types of substrate materials. These samples were then evaluated in both low- and high-speed wear-test programs to determine the wear resistance, microhardness, and adhesion of the coatings. In general, it was found that the wear resistance of the coatings is independent of substrate. Scanning electron micrographs have shown that the coating wear surfaces are very smooth, suggesting slow and continuous removal of the coating during the wear test (that is, adhesive wear). Adhesion between the coating and all substrates was excellent. Microhardness results show that the TiB2 coating is harder than alumina, with a hardness value exceeding 5,000 kg/mm2 measured in one test. The results of the wear tests show that TiB2 coatings have relatively poor wear resistance compared with alumina in low-speed unlubricated sliding environments, but exhibit wear properties comparable with alumina in high-speed unlubricated sliding environments.

Jan 1, 1981

By W. W. Fowler

ORIGINALLY designed for copper smelting only, the reduction works of the Cerro de Pasco Copper Corp. have been expanded over the years until now twelve different metals are produced, together with some seven other items which are used locally. Although the total tonnage treated is comparatively modest, as smelting plants go, the variety of operations makes one of the most complex and interesting metallurgical problems in the world. The original plant, at La Fundicion, operated from July 1906 until September 1923. In 1922 a new copper smelter was built at La Oroya, which produced its first copper on Nov. 23, 1922. It is in this plant, greatly enlarged, that metallurgical operations now center. La Oroya is situated at the junction of the Cerro de Pasco Railroad and the Ferrocarril Central del Peru, at an altitude of 12,175 ft.-well over two miles. Many of the various operations stem from two principal smelting circuits which are themselves of conventional types. Copper ores and concentrates are roasted, smelted in reverberatory furnaces and converters, and blister copper produced. Lead ores, concentrates, and other materials are sintered, smelted in blast furnaces to crude lead which is partially fire-refined, and finally electrolytically refined by a modified Betts process.

Jan 1, 1945

By L. A. Haas

In this Bureau of Mines investigation, conditions were determined to form an iron sulfide adherent coating with a metallic golden luster on steel upon anaerobic heat treatment with sulfur. The sulfide formation rate was determined in the temperature range of 105° to 500° C with reaction times up to 68 hours. The optimum temperature and time to form an adhering decorative coating on mild steel was in the range of 105° C for about 70 hours to 285° C for 1 hour. The golden coating consisted of an inner layer of pyrrhotite and an outer layer of pyrite. At temperatures higher than about 300° C, the outer layer thickness decreased owing to the decomposition of pyrite to pyrrhotite.. Small quantities (<0.5 wt-pct) of petroleum oil accelerated the sulfide growth rate. The sulfide coating decreased the corrosion rate of steel in a neutral aqueous medium by a factor of two. The dissolution of pyrite in water was dependent on particle size and surface area with the flat pyrite coatings exhibiting the lowest dissolution rate.

Jan 1, 1974

By PAUL M. Tyier

NOW that analytical chemistry has gone so far to debunk early misconceptions about minerals, the fact that the light of exact knowledge still fails to illuminate many dark corners is often overlooked. By combining the skills of the physicist with those of a chemist, the identification of minerals has become an exact science and the presence of even minute traces of impurities and extraneous elements is readily revealed by spectrographic means, Granted that we can learn all there is to know about the composition of a substance and even about its physical propertied (which latter assumption is somewhat far-reaching) it still does not follow that we clearly understood its commercial designation or utility.

Jan 1, 1941

By A. R. Biggart

Twenty-sixth Sir Julius Wernher memorial lecture, presented at the Tunnelling '94 symposium held in London, 5-7 July 1994. In describing 18 projects with which he has been involved over a period of 36 years, the author aims to illustrate how technological change and an increase in scientific knowledge have influenced tunnelling practice, which he nevertheless maintains does continue to be an art. Tunnels discussed are: the Silver Street, Blackfriars, Whitechapel, St. Paul's and Waterloo Post Office tunnels, 1958-1969; metro tunnels on the Victoria Line, London, 1962-1970; the introduction of tunnel boring machines (TBMs), 1971-1978, in the Empingham reservoir diversion tunnels in Rutland, the bentonite tunnelling machine experiment at New Cross, the Southern tunnel water main section of the London Ring Main and the Warrington sewer in Cheshire; tunnels in rock 1975-1981, for the Lune Wyre and Megget Manor aquaducts, Weymouth sea outfall and Bristol interceptor sewer; Priestley TBM tunnels 1969-1982; the Greater Cairo wastewater project 1983-1987; Anacostia River crossing, Washington DC 1985-1987; the Channel Tunnel 1987-1992; and the Storebaelt eastern tunnel in Denmark, 1992-1994.

Dec 1, 1994

By H. M. Lewis

The current status of the international zinc market is summarized, and a supply /demand outlook is presented for the next five years. A number of technical problems facing the industry are outlined. Introduction ZINC has sometimes been called the unknown metal. Considering that on a world basis it ranks third among non-ferrous metals in production and consumption, zinc retains a certain modesty. It has no distinctive colour like copper, lacks the low density of aluminum or magnesium and is not always easy to identify as a product. The &apos;spangle&apos; of galvanized steel is probably zinc&apos;s most distinguishing feature. The purpose of this article is to develop an over-all review of zinc. Starting with the current position of the metal, the major factors that will shape its future will be described so that an assessment of the outlook for zinc can be made.

Jan 1, 1978

By Ana Cláudia Carioca

Devido à complexidade dos minérios itabiríticos, sua caracterização é necessária, com ênfase em microestrutura. Muito usado é o microscópio eletrônico de varredura (MEV), com microanalisador químico por dispersão de energia (EDS). Métodos computadorizados/automatizados de análise mineralógica e microestrutural, incluindo a liberação dos minerais, têm sido propostos, usando MEV-EDS. Um desses sistemas analíticos é o MLA (Mineral Liberation Analyser), que usa análise de imagens de elétrons retroespalhados (BSE) e espectros de raios-X (EDS) na identificação dos minerais, em secções polidas de partículas de minérios. Assim, geram-se mapas de composição microestrutural, com informações importantíssimas como liberação, associações minerais e análises modais. Há grande significado estatístico, pois vários milhares de partículas podem ser analisadas. Estudaram-se 4 amostras de minérios de ferro do Quadrilátero Ferrífero, MG, com graus diferentes de complexidade microestrutural. As faixas granulométricas (-0,500+0,300 mm e -0,300+0,212 mm) foram estudadas por difração de raios-X, espectrometria Mössbauer e MLA. Pelos métodos instrumentais, os minerais abundantes foram quartzo e hematita, obviamente; também foram identificados goethita, gibbsita e magnetita, minoritários; em geral, os dados do MLA foram consistentes com esses. O quartzo se encontra liberado em 3 amostras, acima de 90%; a exceção é a amostra APV4 com liberação de 60%, onde o quartzo está associado a hematita (principalmente) e goethita.

Aug 1, 2018

By S. Que

Local community acceptance is a key aspect of planning and managing mining projects, whether through sustainability assessment and reporting or corporate social responsibility programs. However, there has been very little research to understand the determinants of community acceptance. This paper seeks to identify key mine characteristics and demographic factors that influence individual acceptance of mining projects. Six demographic factors and 16 mine characteristics were selected based on literature review. Four of the six demographics factors were confirmed to be significantly (p < 0.05) correlated with people?s attitude of the importance of the mine characteristics. All sixteen mine characteristics are identified as important factors. The most important mining factors are Job opportunities, water shortage or pollution, air pollution and land pollution. Both the mining and control groups have same opinion of 12 mining characteristics and differ on four (infrastructure improvement, labor shortage for other businesses, noise pollution, and mine life). During design and management of mines, this data can be used as a reference. This result will facilitate better choice experiment (survey) design for discrete choice modeling. Such discrete choice models can provide a viable framework for data-driven community engagement and sustainable mine management.

Feb 23, 2014

By Steve Zaffron, Olga Loffredi, Eric Seedorff, Mary Poulton

"The New Face of Mining is a recognition of the central role of human beings in mining and the underappreciated power they can have in generating breakthroughs in business performance and shareholder value. The key is people creating, aligning on, and subsequently enacting the future of mining. A methodology that is effective creates a corporate environment for alignment to be possible and then transforms operations by embedding the necessary behaviors, processes and practices. The people within the organization then are empowered to find and to implement solutions quickly, as measured business results demonstrate in case histories of diverse mining challenges around the globe and over the decades.Urgent case for actionThe physics of mining does not change fundamentally over time, but the context in which it operates changes rapidly, periodically requiring a new face of mining. “The New Face of Mining,” which has been used as a metaphor for the campus-wide mineral resources research organization at the University of Arizona, has many facets, including societal, generational, technological, financial and environmental, but at the center, always, is humanity. The New Face of Mining is not necessarily about age, it is about people first imagining and then creating a new future for mining. The challenges facing the global industry evolve from year to year and differ in individual companies or mines at any one time.Quantified outcomes from case studies indicate that a methodology, now also offered annually in a four-day, open-enrollment leadership program tailored to the mining industry, is effective at generating breakthrough results in the mining business. Such challenges range from those with important technical components to others that are mostly social challenges. Our focus, however, is the centrality of people in aligning on and enacting the future of mining. We use the phrase New Face of Mining for leadership and ways to empower people in organizations that commonly are overlooked in the mining industry. Some of the material in this article is based on the ideas of Werner Erhard and on the book by Steve Zaffron and Dave Logan (2009), The Three Laws of Performance: Rewriting the Future of Your Organization and Your Life.At Davos, Switzerland in January 1992, nine visionary mining chief executive officers (CEO) gathered to create the Global Mining Initiative. Much has changed in the 26 years since that meeting:• The world GDP has increased from US$25.4 trillion to $75.8 trillion.• The annual number of U.S. patent applications increased from 186,000 to 629,000.• The number of websites has increased from 100 to 1 billion.• The number of academic references to artificial intelligence has climbed from more than 16,000 to more than 1 million.• The number of cell phone subscribers grew from 11 million in the United States to four billion globally."

Oct 1, 2019

By L. Garrigues, M. Jarvis, M. Halhead, O. A. Bascur

"Large variability of ore types, escalating variables operating costs and increased throughput require large investment in sensors and systems in mineral processing operations. Mining and mineral processing plants collect and manage more data than a small city with much in real-time. The data is changing rapidly as internal and external conditions evolve. As corporations buy and sell assets, and reengineer their staff, the structure and tools that were used to understand this data is lost. This results in significant deterioration in the ability to maintain a smart operation. When data is recognized as a critical asset and managed as part of an infrastructure, it become a key enabler to help transform the entire operations. In many situations, all partners in business collaboration—such as join ventures, contract manufacturer, expert service providers, and operations and maintenance companies—need access to production and asset data. The emergence and maturation of Cloud technologies make it possible to easily connect the plants to external equipment suppliers and operational support service.This paper will share examples of how mineral processors have adopted new data strategies such as self-service business intelligence, cloud computing and internal/external collaboration.INTRODUCTIONOne of the main challenges in mineral and metallurgical processing plants is effective energy and water management. The lowering of ore grades requires higher throughputs while the ores are getting more complex with variable mineralogical compositions. Electrical energy supply is becoming a restriction in many countries. Rising water management costs has a direct impact on the profitability of the operations. Grade recovery versus energy consumption in copper production for both open pit and underground mines has been described by Fuerstenau (2001). Comminution uses over 55% of the energy to produce nonferrous metals while other operations require much less energy (Nelson, Richins, & Lelinski, 2013)."

Jan 1, 2016

Effective Dry Density Benefication of Coal

Sep 13, 2010

By C. D. Litton

When methods to prevent the occurrence of fire in underground mines fail, the next line of defense is to rapidly and reliably detect the developing fire, so that subsequent evacuation and control procedures can be safely and successfully implemented. To provide this capability requires an understanding of the operational principles of different types of fire sensors, their merits as well as their limitations, and performance characteristics of the monitoring systems that control and process sensor data; an understanding of how fires develop and the different types of fires that can occur, along with their characteristics and the hazards they present; an understanding of the impact of the mine environment and routine mining activities, not only in terms of these effects on fire sensors but also in terms of the impact of mine ventilation and mine geometry on fire growth, fire characteristics and the detection process. All of these factors are components of the technology of fire detection, and when insufficient knowledge of any of these components exists, the ability to implement adequate mine fire detection systems is diminished. Within the last decade, significant advances have been made in fire detection technology applicable to underground mines. These advances include not only the development of improved sensors and better monitoring systems, but also an expanded understanding of how to deploy sensors, set sensor alert/alarm levels, account for ventilation effects, etc. In addition, there has been an increase in our knowledge of the types of fires that occur, the types of combustibles involved, characteristic times for fire growth and development, the levels of heat, smoke and gas that are produced and the hazards that result. It is the intent of this paper to provide not an overview of current mine fire detection technology and, also, to present data obtained for some smoke sensors that have potential for use in underground mines. The paper will also discuss the data, information and resources that are currently available and seek to identify those areas most in need of further research and development.

Jan 1, 2011

By Ry Stone

To maintain longwall continuity, NRE Wongawilli Colliery extracted the approximately 20-year-old Thompson Mains and in doing so, 20 roadways were holed into during longwall retreat. The orientation of these roadways with regard to the longwall face varied between (i) a parallel alignment where the entire roadway was simultaneously subjected to a significant increase in vertical stress on holing and (ii) a more favorable high angle of alignment, meaning that only a portion of the roadway was subjected to an increase in vertical stress on holing. In addition, the longwall holed into and was recovered in one of the existing roadways. The geotechnical environment presented several additional challenges during longwall retreat. The orientation of the stress field resulted in a major horizontal stress notch on the maingate and an elevation in the major horizontal stress in front of the longwall face during the retreat up to an adjacent goaf edge. The presence of geological structure zones also resulted in both swings in the major horizontal stress direction and increased levels of roof deformation. The gate road support designs were based on commonly accepted strata management techniques and principles. The support designs in the hole-through roadways were based on empirical design models generated from (i) aconceptual geomechanical model of pre-driven hole-throughand recovery roads and (ii) a worldwide database on pre-driven hole-throughand recovery roads. Imperative to the success of extracting the panel was a sitespecific strata management process. In this regard, consideration was given to the following: roof displacement monitoring in the gate roads (in particular, Longwall (LW) Acceleration Position), roof-to-floor convergence monitoring in the hole-through roadways, the ability of the mine to limit downtime prior to and during holing by utilizing an Authority to Mine (ATM) type process, and the use of Trigger Action Response Plans (TARP).

Jan 1, 2012

By Y. F. Liang

Fe-6.5wt.%Si alloy has excellent soft magnetic properties compared with conventional silicon steel. It is very brittle at room temperature due to appearance of ordered phases, like B2 and DO3. In this paper, we investigate the effect of ordering on cold workability of this alloy. Methods of rapid quenching and hot rolling were utilized. It is found that rapid quenching and proper heat treatment of the hot rolled sheet could decrease the degree of order due to the very high solidification rate and high cooling rate. The rapid quenched sheet and hot rolled sheet after proper heat treatment could be cold rolled without crack. Microstructure, phase ordering, micro hardness, and cold rolling properties were investigated by Optical Microscope, X-ray Diffraction, Micro Hardness Indenter and Four-high Mill.

Jan 1, 2009

By Georges Ranque

THIS paper by. Georges Ranque is an attempt to reason out the conditions of formation and stability of inclusions and to establish an operative process capable of eliminating or minimizing them. The paper consists of two parts; one in which the author considers the laws of physical chemistry and physics that apply to liquid slag-metal systems and one in which he describes a practice based on the theoretical considerations. Such a paper is bound to contain controversial points and it is therefore your speaker&apos;s intention to present Mr. Ranque&apos;s side of the picture to the best of his ability without regard for any thoughts or criticisms of his own. RISING VELOCITIES OF INCLUSIONS Most nonmetallic inclusions have densities ranging from about 1.7 to s, while liquid steel has a density of about 7. Under these conditions, ferrostatic pressure should cause the inclusions, being lighter, to rise from the bath and be eliminated. This rising tendency is expressed by Stokes&apos; law, from which may be calculated the rising velocity of a spherical particle in a liquid medium whose density and viscosity are known.

Jan 1, 1947

By R. C. D. Phillis

Conventional stoping in hard rock mining is largely considered an operational environment. This paper suggests that stoping falls within the realm of a project management environment typified by uncertainty, variation, and large numbers of interdependencies. Stoping was then equated to a micro-project with many simultaneous activities that had to be executed accurately using finite resources within limited shift durations in order to reach specific goals. Critical chain project management (CCPM) principles were applied to the stoping activities, and the results showed that the number of blasts per panel can be significantly increased by successfully moving the distribution of work as close as possible to the start of shift. Critical chain principles also assisted in facilitating re-focusing and teamwork among stoping crews as well as between day- and night-shift crews. The main recorded success was in managing inherent protective capacities/local contingencies/fat/buffers that are found in all projects. The impact on mine health and safety (MHS) was significant as individual operators and crews became convinced that they could perform all stoping tasks (activities) without compromising accuracy or speed.

Jan 1, 2011

By Rodney T. Jones

DC arc furnaces were first used industrially for the reductive smelting of chromite fines to produce ferrochromium thirty years ago. Since then, they have been used for a variety of applications, including the smelting of ilmenite to produce titania slag and pig iron, the recovery of cobalt from non-ferrous smelter slags, and the smelting of nickel laterite ores to produce ferronickel. The power of these furnaces has increased from 12 MW to 72 MW for ferrochromium, and to 80 MW for ferronickel. The largest of these furnaces requires two electrodes to carry sufficient current to generate this much power. A review is presented of various DC arc furnaces in use, along with a discussion of the likely ways in which furnace power might be increased further in the future.

Jan 1, 2014