A Mineral Dressing Study of the U.S. Grant Ore

This investigation concerns the development of a satis­factory method or extracting or concentrating gold and silver from the ores of the U. S. Grant Mine. The choice between applying an extractive process and one by which the valuable mineral constituents are concentrated depends on more than one factor.

A Mineral Dressing and Economic Study of a Complex Arsenical Ore

The factors that influence the choice of a method for treat­ment of an ore comprise the technical and economic limitations and advantages, derived in detail and balanced according to the exigencies of the particular situation.

A Mineral Dressing Study of the Benefication of Philipsburg Manganese Carbonate Ore

The beneficiation of rhodochrosite ore to the extent that it is suitable for nodulizing and subsequent use in the steel industry is intriguing. Such ores from certain mines is relatively easy to beneficiate, but the rhodo-chrosite ore from several deposits of the Philipsburg district has never been successfully up-graded by any of the several known beneficiating methods.

Mineração, finanças públicas e desenvolvimento local no município de Barcarena - Pará

A presente pesquisa tem como objetivo discutir de que forma a implantação dos projetos de beneficiamento mineral (Albrás, Alunorte, Pará Pigmentos e Imerys Rio Capim Caulim) tem impactado as finanças públicas de Barcarena, e como a prefeitura tem alocado esses recursos para a potencialização do desenvolvimento local. A alocação destes recursos teve como referência as obras físicas, contidas no Plano Plurianual de Barcarena (2002-2005) elaborado pela equipe da primeira gestão do prefeito Laurival Magno Cunha (2001-2004). A pesquisa esta estruturada em dois marcos temporais. No primeiro procuro analisar o município antes da implantação dos projetos minerais, ou seja, as décadas de 1970 e 1980, onde a dinâmica municipal é analisada a partir de dados populacionais, econômicos e das finanças públicas. No segundo marco temporal, procuro investigar o município apos à implantação dos projetos minerais. Neste sentido, estes projetos são estudados a partir da contribuição dos mesmos para a geração de empregos, investimentos realizados em projetos de cidadania e meio ambiente além dos impostos recolhidos por estas empresas. Em seguida, são analisadas a alocação das receitas e as obras físicas contidas no PPA (2002-2005) verificadas através de trabalho de campo se foram ou não realizadas. No trabalho de campo, realizou-se entrevistas com seis representantes dos movimentos sociais, quatro representantes do poder público local, além das empresas estudas. Finalmente é discutido o desenvolvimento local a apartir da visão e lutas dos movimentos sociais de Barcarena onde a participação ou não destes na gestão das obras físicas municipais durante a gestão 2001-2004 figura como ponto principal de investigação da pesquisa.

The Amplifier - v. 9, no. 1

In this issue...New Faculty, Orediggers, Anderson-Carlisle, campus parking, cheerleaders, freshman class, Phil Judd, Mineral dressing, Coach Ed Simonich

The Amplifier - v. 10, no. 1

In this issue...Homecoming Bonfire, campus interviews, Carol Melvin, Berkeley Pit, Pep Band, Chess Club, Alumni Coliseum, cheerleaders, Theta Tau, Mayor Thomas Powers

The Amplifier - v. 12, no. 7

In this issue...International Club, Easter Dance, Tiddledywinks, Mine Rescue, First Aid, Mineral Dressing, College Days, Circle K Club, Sigma Xi

Impacts of limestone and nitrogen top dressing application on the potassium content in the soil profile and marandu-grass leaf concentration

Objetivou-se avaliar os efeitos de nitrogênio (0, 100, 200, 300 e 400 kg/ha.ano), com ou sem aplicação de calcário dolomítico em cobertura, sobre o teor de potássio (K) do solo nas profundidades de 0 a 5; 5 a 10; e 10 a 20 cm e a concentração de potássio na planta. O experimento foi realizado em Latossolo Vermelho distroférrico de relevo suavemente ondulado, disposto em esquema fatorial 5 × 2, em blocos casualizados, com quatro repetições. A adubação nitrogenada promoveu aumento linear na concentração de potássio na planta e no teor desse mineral na camada de 0 a 5 cm do solo. Ocorreu efeito de inibição competitiva entre a absorção de potássio e cálcio e entre potássio e magnésio. Embora uma fração significativa de potássio retorne à camada superficial do solo pelo resíduo de forragem, em decorrência da maior produção de massa, o aumento da concentração de potássio na planta nas mais altas doses de nitrogênio comprova a importância do suprimento de potássio para a planta, por intensificar a massa de forragem.

The use of calcium hydroxide and mineral trioxide aggregate on apexification of a replanted tooth: a case report

To report the outcome of the endodontic treatment of a reimplanted central maxillary incisor with open apex after 8 years and 7 months of follow-up.This case report presents the treatment of a right central maxillary incisor of an 8-year old white male patient with history of traumatic avulsion and immediate replantation. The endodontic therapy consisted of periodical changes of calcium hydroxide dressing and a definitive root canal filling with mineral trioxide aggregate (MTA). The treatment was successful without pathologies up to 7 years of follow-up. After the institution of orthodontic treatment a localized and late root resorption was noticed at the last radiographic examination (8 years and 7 months postoperative follow-up). Moreover, the use of MTA promoted a mild crown grey discoloration.

Clinical and radiographic evaluation of pulpotomies employing calcium hydroxide and trioxide mineral aggregate

This study utilized clinical and radiographic examinations to compare the effectiveness of calcium hydroxide paste and mineral trioxide aggregate (MTA) for pulpotomies of primary molars in children. Ninety primary molars that showed clinical and radiographic indications for pulpotomy treatment were selected. The pulpotomies were performed in two sessions, using a corticosteroid/ antibiotic solution as therapeutic dressing. The sample was divided into two groups of 45 teeth, in which the pulpal remains were protected with either calcium hydroxide paste (Group 1) or MTA (Group 2). Radiographs were taken immediately and at 3-, 6-, and 12-month follow-up appointments. Three teeth in Group 1 failed after three months, while two cases failed after six months and one more failed at one year. Two failures were found in Group 2 at the 12-month follow-up. These results indicate that both materials may be utilized for pulpotomies in primary teeth.

The'cave' mineral oxammite: a high resolution thermogravimetry and Raman spectroscopic study

The thermal decomposition of natural ammonium oxalate known as oxammite has been studied using a combination of high resolution thermogravimetry coupled to an evolved gas mass spectrometer and Raman spectroscopy coupled to a thermal stage. Three mass loss steps were found at 57, 175 and 188°C attributed to dehydration, ammonia evolution and carbon dioxide evolution respectively. Raman spectroscopy shows two bands at 3235 and 3030 cm-1 attributed to the OH stretching vibrations and three bands at 2995, 2900 and 2879 cm-1, attributed to the NH vibrational modes. The thermal degradation of oxammite may be followed by the loss of intensity of these bands. No intensity remains in the OH stretching bands at 100°C and the NH stretching bands show no intensity at 200°C. Multiple CO symmetric stretching bands are observed at 1473, 1454, 1447 and 1431cm-1, suggesting that the mineral oxammite is composed of a mixture of chemicals including ammonium oxalate dihydrate, ammonium oxalate monohydrate and anhydrous ammonium oxalate.

Synthesis and characterization of K2Ca5(SO4)6· H2O, the equivalent of görgeyite, a rare evaporite mineral

Görgeyite, K2Ca5(SO4)6··H2O, is a very rare monoclinic double salt found in evaporites related to the slightly more common mineral syngenite. At 1 atmosphere with increasing external temperature from 25 to 150 °C, the following succession of minerals was formed: first gypsum and K2O, followed at 100 °C by görgeyite. Changes in concentration at 150 °C due to evaporation resulted in the formation of syngenite and finally arcanite. Under hydrothermal conditions, the succession is syngenite at 50 °C, followed by görgyeite at 100 and 150 °C. Increasing the synthesis time at 100 °C and 1 atmosphere showed that initially gypsum was formed, later being replaced by görgeyite. Finally görgeyite was replaced by syngenite, indicating that görgeyite is a metastable phase under these conditions. Under hydrothermal conditions, syngenite plus a small amount of gypsum was formed, after two days being replaced by görgeyite. No further changes were observed with increasing time. Pure görgeyite showed elongated crystals approximately 500 to 1000 µ m in length. The infrared and Raman spectra are mainly showing the vibrational modes of the sulfate groups and the crystal water (structural water). Water is characterized by OH-stretching modes at 3526 and 3577 cm–1 , OH-bending modes at 1615 and 1647 cm–1 , and an OH-libration mode at 876 cm–1 . The sulfate 1 mode is weak in the infrared but showed strong bands at 1005 and 1013 cm–1 in the Raman spectrum. The 2 mode also showed strong bands in the Raman spectrum at 433, 440, 457, and 480 cm–1 . The 3 mode is characterized by a complex set of bands in both infrared and Raman spectra around 1150 cm–1 , whereas 4 is found at 650 cm–1.