Anthracite
Mostrando 13-13 de 13 artigos, teses e dissertações.
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13. The relationship between coal rank and the prevalence of pneumoconiosis.
As part of the Periodic X-ray Scheme of the National Coal Board (NCB), a comparison is made between the previous and new films of all miners who were face-workers on the former occasion, five years earlier. This assessment is made by distributing the films randomly to all the NCB readers. This paper compares the rank of coal mined in each colliery with each