miscellanea The P 4 SR index-a critique of a recent criticism
In the October 1967 issue of this Journal there appeared a paper, entitled 'Assessing the Heat Stress and Establishing the Limits for Work in a Hot Mine' (Wyndham, Allan, Bredell, and Andrew, 1967), in which an account was given of an investigation conducted underground at Mount Isa Mine in Queensland. The purpose of the investigation was twofold: to determine which of three commonly used indices of heat stress wet-bulb temperature, corrected effective temperature, or the P4SR index predicts most accurately the effects on workmen underground of the several factors concerned in heat stress, and to decide, in terms of the selected index, at what level of heat stress the length of shift should be reduced or work should cease. The reason for undertaking the enquiry, despite the fact that heat-work tolerance has been investigated many times before, is stated by Professor Wyndham and his co-authors (p. 256,1 col. 1) to be that:
The Influence of High Air Temperatures No. I
The aim of the following investigations was to ascertain the limits within which men can continue to exist normally, and to work, when the air temperature is abnormally high: also to study the abnormal phenomena which are produced when these limits are exceeded.
Soil organic matter and microbiological development of technosols in the South Wales Coalfield
Abstract Degraded land (formerly ‘reclaimed’) after surface-coal-mining is a serious problem in South Wales. This project uses forestation to foster soil development on opencast coal-mine spoil technosols. It compares records of humification and the soil microbiological system (microcoenosis) using paired data from the same plantings in 1998 and 2018. Statistical analysis finds no significant difference between samples collected under trees planted by the pit-planting versus trench planting method or trees planted using organic or mineral fertilizer. However, there are strong significant differences in both soil organic matter and microflora components and significant correlations with time since tree planting. Most components of the soil organic carbon (TOC) and the microflora increase, often significantly. However, compared to 2018, 1998 samples contain significantly greater maximum levels of Insoluble Carbon while the microflora had significantly more Ammonifying bacteria. Decreases in Insoluble Carbon explain the relatively small increase in TOC between 1998 and 2018. The % extracted with 0.1 N H2SO4 is significantly larger in 2018, suggesting active weathering. Similarly, both the maxima and minima of total Humic and Fulvic acids content, extracted with 0.1 M Na4P2O7 + 0.1 M NaOH, are significantly greater in 2018. Total microflora shows significant positive correlations with time-since-tree-planting as do the proportions of bacilli and actinomycetes but the correlation with ammonifying bacteria is negative. In 1998, the microflora was dominated by non-spore-forming bacteria while, in 2018, bacilli and actinomycetes prevail; both are involved in the transformation of complex organic compounds and humification. This indicates active transformation of more complex organic compounds and advancing humification. In sum, forestation of these degraded, formerly reclaimed, opencast coal-mine spoils has resulted in a massive increase in both the size and functioning of the soil organic system.