Airborne respirable dust in fully mechanised underground metalliferous mines – Generation, health impacts and control measures for cleaner production

Highlights

• Comprehensive review on airborne dust generation and control issues focusing FMUMM.

• Elucidated characteristics and health impacts of airborne respirable mine dusts.

• Crystalline silica, DPM and radon progeny aerosols are human carcinogen.

• Analyzed and presented effective dust control strategies for FMUMM.

• Explored future research directions on dust dispersion, monitoring, control in FMUMM.

Abstract

Mining operations are inherently associated with dust generation, which is detrimental to cleaner production in mines. Exposure to airborne respirable dust causes serious health hazards to the miners. This paper critically reviews the different dust generating sources in fully mechanised underground metalliferous mines (FMUMM). Moreover, it discusses the classification, characteristics, health impacts, and legislative guidelines of dust in underground metalliferous mines. The monitoring, mitigation, and control measures of airborne respirable dust in major mining operations for cleaner production in FMUMM, have also been discussed in detail. In addition, the generation and health issues concerning microscopic particulates, such as diesel particulate matter and radon progeny associated with dust particles in FMUMM have been elucidated. This article also discusses the recent research activities, identifies the gap areas and suggests the scope for future research on this important topic for improving the workplace environment and protecting health and safety of the miners in FMUMM. This comprehensive review encompassing various issues concerning airborne respirable dust in FMUMM can serve as a first-hand reference material for the academicians, researchers, and practising mine environmentalists.

Introduction

Generation of dust is invariably associated with mining, as most mining operations cause size reduction of rocks and minerals due to drilling, cutting, crushing, grinding, etc. In recent years, heavy mechanisation of the mines due to increased demand for minerals has resulted in a sharp increase in dust generation and the miners’ health risk (Biffi and Belle, 2003). The principle of underground metalliferous mining and dust generating sources are shown in Fig. 1 (Hamrin, 2001). Nowadays, diesel operated mobile equipment, such as LPDTs (low profile dump trucks) and LHDs (load haul dumpers), are extensively used in trackless fully mechanised underground metalliferous mines (FMUMM) (i.e., a mine with no rails, where tyre mounted vehicles are used for haulage and transportation) because of their flexibility in operation and productivity. These equipment, which frequently operate in the declines or ramps serving as intake airways and transportation of men and material in FMUMM, constitute a major source of DPM and significantly contribute to mineral dust aerosolization.

In declines, the reduction or stagnation of airflow due to leakage in the upper sections of mine creates more dust problems (van den Berg et al., 2019). Due to inadequate ventilation in declines and other working areas in FMUMM, miners are exposed to a high level of mineral dust, heat, and other contaminants such as DPM, radon progeny, etc. (Cecala et al., 2012; Sahu et al., 2014b; Panigrahi et al., 2015; Wallace et al., 2015). Consequently, depending upon the type of dust and their combinations, they suffer from various respiratory diseases, such as chronic bronchitis, silicosis, asbestosis, talcosis, siderosis, lung cancer, etc. (Fermor, 1975; Banerjee, 2003; AIOH, 2009; Cullinan et al., 2017; ICRP, 2017).

Apart from adverse health effects, the corrosive effect of dust particles reduces the life of lubricants used in heavy earth moving machineries (HEMM) and in turn, increases their maintenance cost due to excessive wear and premature failure of the machine components (Pandey, 2012). Moreover, the dusty underground mine environment affects the laser-based navigation and electrical systems used in autonomous mining operations (Ghodrati et al., 2015; Gustafson et al., 2017). Hence, it is important to dilute and suppress the mine dusts to a safer level for maintaining a safe and productive workplace environment in FMUMM.

The dust problems in underground mines can be solved by proper ventilation through a well-designed ventilation system. The critical contaminants of mine environment, such as dust particulates and heat, should be considered while designing the ventilation system for FMUMM (Biffi and Belle, 2003; Gonen, 2018). In the past, studies related to mine dust mainly focused on the dust exposure of miners, dust dispersion and control measures in mechanised underground coal mines (Toraño et al., 2011; Kurnia et al., 2014; Mishra et al., 2019; Ren and Wang, 2019). Some studies have also reported the generation and estimation of mine dust in surface mining operations (Chakraborty et al., 2002; Ghose, 2004; Gautam and Patra, 2015; Patra et al., 2015). However, studies on mine dust and their control measures in FMUMM are limited (Biffi and Belle, 2003; Bugarski et al., 2012; Saarikoski et al., 2018). Hence, there is a necessity to conduct more studies on dust related issues for improving the workplace environment in FMUMM.

This comprehensive review focused on the issues concerning all kinds of airborne respirable dusts (ARD), including two important aerosols, viz. diesel particulate matter (DPM) and radon progeny, found in FMUMM. It covered a gamut of topics, such as generation, classification, characteristics, health and safety concerns, legislative guidelines, monitoring, and mitigation and control measures of ARD in major mining operations in underground metalliferous mines. Moreover, it highlighted the current research activities, knowledge gaps and explored ideas for future research on dust dispersion, monitoring and control to maintain a safe, healthy, clean and productive workplace environment in FMUMM. Overall, the knowledge disseminated through this review can greatly benefit the mining industry.