The relationship between coal rank and the prevalence of pneumoconiosis.

Abstract

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 colliery's percentage prevalence of pneumoconiosis of at least ILO category 1 in the films of previous faceworkers obtained during the third survey round . Of the NCB's 291 collieries in Britain, information enabling a rank classification to be made was available for 250, employing 62 362 face-workers. In these 250 mines a progressive and five-fold increase in prevalence was observed from collieries mining low-rank (bituminous) coal to those mining coal of high ranks (anthracite and high-grade steam and coking ccal). A possible reascn for this is that, in the past, high-rank collieries may have had the highest mass-concentrations of respirable dust.

Silicosis and coal workers' pneumoconiosis.

“…As rank increases, the ratio of carbon to other chemicals and mineral contaminants increases. In general, anthracite coal mining has been associated with higher rates of pneumoconiosis than that found in bituminous miners (36,37). Anthracite coal mine dust contains more surface free radicals than bituminous coal, which may explain its higher cytotoxicity and pathogenicity (38)(39)(40).…”

Coal and the lung.

“…In general, there seems to be a relationship between rank of coal (that is, an index of combustibility related approximately to carbon content) and risk of disease-high-rank, high-carbon coals being most dangerous.8 9 This fits well with the observed high prevalence of disease in South Wales and also with the pattern in the United States. Men exposed in the past to high-rank coals in Britain, however, have also traditionally been exposed to very high dust levels, and high-rank coal is rather non-toxic when examined in vitro.…”

Prevalence and pathogenesis of pneumoconiosis in coal workers.

“…High exposure to clay minerals (kaolin and mica) apparently antagonized the hazard from increasing quartz exposure, and the existence of a factor or factors varying between collieries but not reflected in the available environmental data was postulated (3). A well-marked connection was demonstrated between a radiological category of at least 1/0 and rank of coal mined; there was a fivefold increase of prevalence in miners who worked in high rank collieries compared to those who worked in low rank collieries (11). However, large differences in prevalence were also found between separate areas in the coal field of equal rank, suggesting that factors other than rank, such as dust concentration, were involved.…”