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| Darmstadter, Joel; Kropp, Brian. |
| Labor productivity in U.S. coal mining increased at an average annual rate of slightly over four percent during the past 45 years. This report examines key factors contributing to that record - particularly, technological innovation in both surface and underground mining and concurrent geographic shifts in U.S. coal production. Health, safety, and environmental regulations introduced in the sixties and seventies, as well as labor unrest, interrupted long-term productivity advance; but the interruption was of limited duration. Although our principal focus is on worker productivity, steady growth in the relative importance of nonlabor inputs underscores the need to consider total factor productivity. The report touches on the productivity record using that... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Coal mining; Productivity; Technological change; Resource /Energy Economics and Policy; Q41; L72; O31. |
| Ano: 1997 |
URL: http://purl.umn.edu/10874 |
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| Castro-Silva,Marcus Adonai; Lima,André Oliveira de Souza; Gerchenski,Ana Valéria; Jaques,Daniela Batista; Rodrigues,André Luis; Souza,Pricila Lima de; Rörig,Leonardo Rubi. |
| The coal mining activity is characterized by the generation of large amount of by-products. One of them is pyrite, which tends to acidify the water, solubilizing heavy metals. As a consequence the environment becomes acid and rich in heavy metals, selecting microorganisms able to survive in this condition, which are of great interest as bioremediation agents. This work describes the isolation and characterization of microorganisms from a coal mining area in Santa Catarina. These microorganisms comprised bacteria, fungi and yeasts resistant to zinc, nickel and cadmium. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heavy metal resistance; Coal mining; Acidophilic microorganisms; Bioremediation. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822003000500015 |
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