Working in hot conditions in mining: a literature review

This review of the literature on working in hot conditions in mining was originally written for the Health and Safety Executive’s Mines and Quarries Inspectorate to provide them with a collated source of information in formulating possible legislative policy for UK mines. Most of the hot mines in the UK are coal mines. The one potash mine also has hot conditions although neither that nor the coal mines appear to have thermal conditions as severe as those encountered on the European mainland.The review includes a brief overview of thermal physiology: environmental and metabolic heat loads and the physiological and behavioural responses to such loads. It also encompasses methods for the assessment of hot conditions either directly, through the measurement of physiological strain, or indirectly via thermal indices.These elements are then examined in the context of UK mining conditions with sections on the thermal and metabolic heat loads reported in coal and potash mines and an assessment of those thermal indices which suitably reflect the potential effects of such loadings. The Basic Effective Temperature (BET) index is currently used in both the coal and potash mining industries. Although this index has its limitations the review concluded that, as a ‘first order’ monitoring index, the BET scale would appear to predict heat strain with an acceptable degree of accuracy within the range of climates currently encountered in hot UK mines.Fluctuations in environmental heat load are reported, both over time and between adjacent locations. The review draws attention to the need to take both these fluctuations and those of metabolic heat load into account in formulating a method for determining and evaluating the likely degree of thermal stress. The calculated thermal stress will usually be evaluated against some form of Standard or criterion. The review examines those Standards etc. already in use and concludes that, depending upon work rate and pattern, an action limit of between 27 and 31�C BET can be applied.Finally the review examines various control measures such as refrigeration and personal cooling for their potential impact on the workforce. It concludes that many of those currently employed have some merit although many can have undesirable ‘side-effects’. For example, local cooling can create problems elsewhere underground where the extracted heat is discharged. “”