Dust pollution hazard and harmful airborne dust exposure assessment for remote LHD operator in underground lead-zinc ore mine open stope

Dust pollution hazard and harmful airborne dust exposure assessment for remote LHD operator in underground lead-zinc ore mine open stope | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Dust pollution hazard and harmful airborne dust exposure assessment for remote LHD operator in underground lead-zinc ore mine open stope B Paluchamy, Devi Prasad Mishra This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1390084/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Underground mines have several occupational hazards, including airborne dust generated from various mining operations. Line-of-sight remote LHD mucking is adopted to draw the blasted muck from unsupported stopes in underground metalliferous mines. Investigation on particulate matter (PM) at remote operator location is crucial for assessing the operator exposure and devising appropriate dust control measures. This paper identifies the potential dust pollution hazard for remote LHD operator by simulating different mucking scenarios in open stope. PM generated due to mucking in a long-hole open stope by line-of-sight remote LHD during downcast airflow are measured using real-time aerosol spectrometers. The particulates concentration at upstream and downstream of dust source are analysed for various particle sizes including occupational dust types, such as alveolic and thoracic. The study revealed that the airborne dust concentrations of ≤10 μm, ≤5 μm, and ≤1 μm sizes in downstream, near the operator location, are measured 71.3%, 28.5%, and 3.0%, respectively. Moreover, the alveoli and thoracic dust fractions, respectively are determined 25.1% and 74.2%, in downstream and 48.9%, and 84.6%, in upstream total airborne dust concentration (311±246 μg/m3). The differential concentrations of 15.0-20.0 µm, 10.0-15.0 µm 5.0-10.0 µm, and 0.23.0-5.0 µm are analysed, and empirical relations of these sizes in total airborne dust are established. Moreover, dilution of airborne dust at remote LHD operator location is studied. This study enhanced the understanding on exposure potential of harmful dust during remote LHD mucking in open stopes. Moreover, it emphasised adoption of tele-remote-operated LHD and automated mucking operation in open stopes. Dust pollution hazard airborne dust dust exposure remote LHD operator underground lead-zinc ore mine underground mine environment mines safety Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 1. Introduction Underground mining is the process by which the naturally occurring mineral deposits are extracted from underground by employing various mining methods (supported, unsupported and caving methods) (Hamrin, 2001 ). The mining processes, such as drilling, blasting, mucking, hauling, crushing, etc. inherently produce particulate matter (PM) due to breaking down of rocks. The primary dust (generated due to mechanical forces), and secondary dust (airborne due to aerosolisation) are transported to other workings and non-working areas along with ventilating air current in underground mines and influence the downstream airborne dust concentration (Paluchamy et al., 2021 ). In day-to-day mining operations, miners are exposed to various airborne contaminants, which may cause occupational respiratory diseases in coal and metalliferous mines (Ambastha and Haritash, 2022 ; Chen et al., 2022 ; Zilaout et al., 2017 ). The significant amount of dust generated due to production blasting is diluted by ventilating air, and a large quantity of dust is trapped under the blasted rock fragments in stopes (Chekan et al., 2004 ). If precautions such as wetting of rock fragments before mucking are not taken, the trapped dust poses an airborne dust hazard. Nevertheless, wetting of muck pile in stopes is not easy as it has inherent difficulties, such as requirement of a safe location for the person to stand, water spray reachability, duration of spray, spray water penetration into the muck, etc., resulting abundance of dry dust in open stopes (Chekan et al., 2001 ). Identification of hazards is crucial in the risk assessment process, as the new operation could bring unidentified hazards in the workplace. This research paper focuses on dust pollution hazard identification during a typical remote LHD mucking in underground metalliferous mine open stopes. The analysis results can aid in development of low-cost sensor-based dust monitoring and control system for mechanised underground mines. Mucking and hauling of un-wetted blasted rock fragments with load haul dumpers (LHDs) in underground metalliferous mine development headings and stopes liberate large amounts of particulates. LHD is a rubber-tired, low-profile front-end loader used in underground mines or tunnels to load the fragmented/blasted rocks in its scoop, haul them to an unloading point and dump the muck. LHDs have environmentally protected cabins for protecting the operator from dust and heat. However, the environment inside the cabin depends on many parameters that include design and operational factors (Cecala et al., 2019 ). LHDs are commonly operated in unsupported areas in underground metalliferous mines using line-of-sight remote control (i.e., the operator operates the machine under his direct eyesight using remote) to enhance the operator safety and productivity (Schunnesson et al., 2001 ). The line-of-sight remote LHD operation has several advantages that include reliable operation, no network delay, low investment, etc. However, the line-of-sight remote controlled LHD operation range is limited within the operator's visual range and cannot be as fast as an on-board operator. The LHD operator usually stands and operates the LHD remotely from a safe distance of 10 to 40 m in line-of-sight of stope corner (Swart et al., 2002 ). During line-of-sight remote LHD mucking, the LHD operator stays inside the LHD cabin until he reaches near stope brow, a safe place where he can come out of the cabin with a remote and send the LHD inside the stope to draw the muck (WSN, 2012 ). The significant steps involved in line-of-sight remote LHD mucking is specified in Fig. 1 . The LHD cabin door is required to be opened and closed, thereby allows the outside dusty air enter the cabin two times in a regular cycle. Hence, there is a possibility that the remote LHD operator can directly be exposed to harmful mineral dust, heat, diesel engine exhaust fumes, and DPM (Du et al., 2020 ; Ping et al., 2019 ). Figure 1 a illustrates the top view of a typical open stope while the LHD drawing blasted muck inside the stope. Figure 1 b shows the typical remote operator location (e.g., safe sides in the mucking drive, specified size x-cut for operator to stand and operate the LHD), with the visual range of LHD. In the mucking drive, the loaded LHD is manually operated to reach the unloading point (Fig. 1 c). The generation and distribution of dust in underground metalliferous mines can vary with various mining activities and ore properties. Limited studies have been conducted on mineral dust generation in mechanised underground metalliferous mines (Biffi and Belle, 2003 ; Saarikoski et al., 2018 ). Studies have confirmed that the adverse health effects of airborne dust depends on size (including nano size particles) and concentration of dust, toxic substance/elements present in the dust, and miners’ exposure to the dust (NIOSH, 2002 ; Zheng et al., 2013 ). Few researches have been conducted on dilution of exhaust fumes generated during LHD mucking in stopes (Nakaryakov and Grishin, 2021 ). However, past studies did not assess the generation and dispersion profiles of dust based on particle size, which is very important from the occupational health hazard point of view and for devising appropriate dust control strategies in underground metalliferous mines. No study has been conducted on airborne dust generation and dispersion in open-stopes of mechanised underground metalliferous mines. Use of electric LHDs though eliminates diesel exhaust fumes and DPM hazard in underground working environment, the mineral dusts generated owing to their use could pose health hazard. Keeping this in mind, this study focuses on the identification of dust pollution hazard and assesses the airborne dust generated due to line-of-sight remote LHD (17 tonne capacity) mucking in underground lead-zinc ore mine open stopes under downcast airflow. Moreover, it analyses the concentrations of airborne dust in upstream (baseline) and downstream sides of the working stope. 2. Materials And Methods 2.1. Approach In this study, the dust pollution hazard for remote LHD operator engaged in mucking in open stopes is identified by simulating different working scenarios. In order to achieve the study objectives, the important factors, such as site selection, field monitoring and procedures followed during the field study, data analysis and empirical relation development are outlined. Airborne particulates sampling is conducted at the study site using real-time aerosol spectrometers to quantify the harmful airborne dusts. Furthermore, relevant ventilation parameters, such as dry-bulb temperature (DBT), wet-bulb temperature (WBT), relative humidity (RH), equipment movement, and drive dimensions are measured to examine the behaviour and relative size distribution of dusts. 2.2. Site selection The study site was selected based on the level of mechanisation implemented in various mining operations, accessibility, and safe installation of dust monitoring equipment. Kayad lead-zinc mine (KLZM) of Hindustan Zinc Limited (HZL), an active and fully mechanised underground lead-zinc mine in India, was selected for the field study. The KLZM is located in Kayad village, Ajmer city of Rajasthan state as shown in Fig. 2 . The mine is relatively shallow in depth. The main access to the mine is through the main decline. The surface level of the mine is 487 mRL. The mine decline is of 5.50 m × 5.00 m (W × H) cross-section with arched roof and gradient 1 in 7. The main decline split into north decline and south decline at 412 mRL (Fig. 2 ). The study was conducted at 375 mRL in the north section. A working longhole open stope was identified in 375–400 mRL for subsequent field monitoring. Boundary and exhaust ventilation system is implemented to fulfil the ventilation requirement of the mine. All the mine ventilation fan speeds are regulated by variable frequency drive (VFD). 2.3. Data collection The mass concentration and size distribution of airborne dust were monitored using Grimm aerosol spectrometers (model 1.108) with necessary field measurement accessories. The percentage of respirable dust is a function of dust particle size. Recent studies showed that finer dust particles have more impact on human lungs in a typical mining environment (Gautam et al., 2015 ; Patra et al., 2016 ). Therefore, the aerosol spectrometers which can classify up to 15 size ranges starting from 0.23 to 20 micron were used in this study. The aerosol spectrometers also classify the airborne dusts in terms of respirable, thoracic and inhalable dust types (Grimm, 2010 ). ‘Mass Distribution’ option was selected in operational mode, and the rest of the values kept default in this study. The average airflow velocity in the study area was measured using a vane anemometer (Micon-2 dial). The temperature and relative humidity were measured using a humidity meter (Lutron: PHB-318) during the LHD movement in the study area. The dust monitors were placed near the breathing zone at about 1.6 m height beside the mucking drive wall to prevent their damage from moving LHD. Engineering sampling (Belle, 2018 ) was adopted for measuring the dust generation and dispersion due to line-of-sight remote LHD mucking in the open stope. Here, engineering sample represents the airborne dust sample collected to characterise the dust emission source when the particular engineering activity (e.g., LHD mucking in this case) is taking place. Moreover, LHD entry and exit times in the monitoring area were recorded. 3. Results And Discussion 3.1. Dust pollution hazard identification for remote LHD operator in open stopes Figure 3 shows a layout illustrating the typical airflow scenarios in an open stope during line-of-sight remote LHD mucking. A well-planned ventilation network will have the airflow direction as marked in the drilling level (a-b-c-g) and mucking level (d-e-f-c-g) drives (Fig. 3 a). As depicted in Fig. 3 a, the remote LHD operator location in the mucking level drive is ventilated by intake air from decline, and the stope exhaust air is directed to the return drive in drill level. However, the other two scenarios illustrate that the remote LHD operator location is contaminated by stope exhaust air, which contains harmful diesel exhaust and airborne mineral dust due to downcast airflow (Fig. 3 b) and recirculation (Fig. 3 c) of air in the working stope, respectively. The direction of primary airflow in the stope as depicted in Fig. 3 b, 3 c may be caused by unplanned obstructions in the airways, opening or closing of ventilation doors, connecting development drives in different working levels, opening or backfilling of stopes, and unexpected stoppage of main fans in mechanised underground metalliferous mines. Based on the simulation results for a typical remote LHD mucking scenarios, these undesired downcast and recirculation of airflow in open stopes may lead to the exposure of remote LHD operator to harmful airborne contaminants, such as airborne mineral dust, diesel engine exhaust gases, and diesel particulate matter (DPM) during line-of-sight remote LHD mucking. This study aimed to investigate the concentration of harmful airborne dusts at remote operator location for the two scenarios shown in Figs. 3 b, 3 c in a highly mechanised underground metalliferous mine. However, a working stope having air recirculation scenario (Fig. 3 c) was not found during the field study in the mine. 3.2. Line-of-sight remote LHD mucking operations in KLZM Commonly, LHDs are involved in mucking of blasted muck or rock fragments from the working face and hauling to unloading points, such as truck or dump stockpile (DSP), and loading and hauling material for backfilling in KLZM. The shift in-charges and LHD operators provided the preliminary information about dust flow patterns (e.g., downcast and upcast airflow) in production stopes. Usually, the dust generated by the mucking operation does not affect the operator during upcast airflow (Fig. 3 a). Hence, the downcast-airflow scenario in a working stope in North section of the mine was considered for assessment of harmful airborne dust at remote LHD operator location (Fig. 4 ). The results of airborne dust analysis at remote operator location due to mucking in the open stope under downcast-airflow is presented subsequently. Figure 4 illustrates the variation of dust concentration in mucking level drive due to remote LHD mucking in the stope under downcast-airflow. The LHD operator adjusted the distance between the mucking point (i.e., remote LHD in stope) and his location between 20 to 50 m depending upon the visibility and safe place during line-of-site remote LHD operation. The average velocity of airflow at monitoring location in the drive was measured 0.7 m/s. The drive was of 5 m×4.5 m cross-section with arched roof, over break due to earlier down-level stopes, and wetted rock surfaces (sides and floor). The dust monitor was placed at a distance of 45 m from the dust source (i.e., LHD mucking) at a height of about 1.6 m in side of the mucking drive (Fig. 4 ). Moreover, the necessary distance was set aside for the generated dust in the stope to mix with mine air before reaching the dust monitor location. The DBT, RH, O 2 and CO concentrations in the dust monitoring location during mucking were measured in the range of 28.5–30.5°C, 82 − 77%, 20.6–20.9%, and 5–10 ppm, respectively. The general statistics and regression analysis of airborne dust measured during the field study have been summarised in the following section. 3.3. Assessment of airborne dust The average concentration of total airborne dust (TAD) in upstream (i.e., baseline) and downstream side at the remote operator location are estimated 311 ± 246 µg/m 3 and 6210 ± 2690 µg/m 3 , respectively (number of readings, N = 10 cycle). During the field study the blasted muck was in dry condition. Normal operating procedures at mines do require wetting of the muck piles prior to loading. However, the longhole-open stoping method of mining can make wetting of the blasted muck in stopes difficult at times (Chekan et al., 2001 ). Figure 5 presents the cumulative dust concentrations and percent proportions of ≤ 20 µm, ≤ 15 µm, ≤ 10 µm, ≤ 5 µm, and ≤ 1 µm size dusts in TAD. The analysis of particulates revealed the proportion of ≤ 20 µm, ≤ 15 µm, ≤ 10 µm, ≤ 5 µm, and ≤ 1 µm dusts in downstream TAD in the ranges of 89.4–100%, 84.0-95.2%, 67.7–75.2%, 24.8–39.3%, 1.6–8.6%, respectively. In Fig. 5 , it is evident that the dust particles greater than 10 µm size, which is not in respirable range (DGMS, 2010 ), constitute 29.7% and remaining ≤ 10 µm dusts share 71.3% in the downstream TAD. Moreover, the percent proportion of ≤ 5 µm and ≤ 1 µm in the downstream TAD are estimated 28.5% and 3.0%, respectively. Another study by the authors in a decline of the same mine indicated the percent proportions of 6% and 0.5% for ≤ 5 µm and ≤ 1 µm, respectively in downstream TAD generated due to loaded LPDT travelling, which are much lower than in stope mucking areas (Paluchamy and Mishra, 2021 ). Nevertheless, the air velocity in the decline was higher (3 m/s) than the stope mucking drive (0.7 m/s). The low air velocity in the mucking drive might have facilitated quick settling of the coarser particles before reaching the aerosol monitor. Moreover, the air velocity inside the stope is lower than the mucking drive due to larger void space in the stope. The airborne dust was also analysed in terms of occupational dust types, such as alveolic and thoracic (CEN, 1993). The percent proportions of alveolic and thoracic dusts in respective inhalable dust concentrations of upstream and downstream sides are shown in Fig. 6 . The downstream concentration of inhalable dust at remote operator location in the mucking drive was measured in the range of 2192–10433 µg/m 3 . From Fig. 6 , it may be observed that the proportions of alveolic (48.9%) and thoracic (84.6%) dusts in the upstream side are higher than the respective dust types (i.e., 25.1% alveolic, and 74.2% thoracic) in downstream side. However, upstream inhalable dust concentration was found in the range of 93–759 µg/m 3 , which is due to dust concentration in declines as the North decline air serves as one of the primary intakes of the stope. Studies have confirmed that alveolic particulates fraction is the most hazardous as they penetrate beyond the terminal bronchioles into the gas-exchange region of the lungs (WHO, 1999 ). Moreover, the dust capturing efficiency of wet suppression system for respirable dust is lesser than the coarser particles. Though ventilation is one of the effective means of diluting respirable dust in stopes, wetting the blasted muck is of paramount importance to prevent the dust becoming airborne in stope (Chekan et al., 2001 ). Further analysis of downstream airborne dust concentration (Fig. 7 ) led to the establishment of following linear empirical relationships between the alveolic, thoracic and inhalable dust concentrations: y 1 = 0.2039x + 290.53 (1) y 2 = 0.7417x + 2.7998 (2) where y 1 and y 2 are concentrations of alveolic and thoracic dust types in inhalable dust, and x is inhalable dust concentration in downstream. These relationships will be useful for assessing the concentration of alveolic dust from the known total airborne dust concentration in similar working areas. The differential dust concentrations of various size ranges plotted against the total airborne dust (TAD) in Fig. 8 depict that the concentrations of dust sizes 15.0–20.0 µm, 10.0–15.0 µm 5.0–10.0 µm, and 0.23.0–5.0 µm linearly increase with increase in the concentration of TAD in downstream air. Differential concentration of downstream airborne dust (DS) for the size ranges of 15.0–20.0 µm,10.0–15.0 µm 5.0–10.0 µm, and 0.23-5.0 µm, was analysed in the range of 0-707 µg/m 3 , 315–2205 µg/m 3 , 786–4577 µg/m 3 , and 862–2756 µg/m 3 , respectively. The respirable dust of ≤ 5 µm size is considered to be more hazardous. The large variation in concentration (i.e., 862–2756 µg/m 3 ) of 0.23-5.0 µm size dust in the downstream air may be attributed to the variation in LHD bucket filling and muck sliding in different mucking cycle. Moreover, the analysis revealed better correlations for the 10.0–15.0 µm and 5.0–10.0 µm (R 2 = 0.95 and 0.98) size ranges than the coarser sizes (i.e., 15.0–20.0 µm) (R 2 = 0.76) with TAD. Empirical correlations established for different particle size ranges are given below. y 3 = 0.0689x − 82.374 (3) y 4 = 0.2387x − 299.76 (4) y 5 = 0.4664x − 237.74 (5) y 6 = 0.2352x + 310.38 (6) where y 3 , y 4 , y 5 , and y 6 are dust concentrations of the size ranges of 15.0–20.0 µm, 10.0–15.0 µm 5.0–10.0 µm, and 0.23.0–5.0 µm, respectively. ‘x’ is the concentration of TAD in downstream. The analysis of various particle sizes, such as finer and coarser particles in TAD, will facilitate the assessment of particles deposition in human respiratory tract (Patra et al., 2016 ). Moreover, the aforementioned relationships established through this research will aid environmental monitoring and smart dust control through wireless sensor network (WSN) in mechanised underground mines (Muduli et al., 2018 ). Apart from airborne dust exposure risk, the remote LHD operator may also be exposed to harmful exhaust gases and other sub-micron particulates, such as diesel particulate matter (DPM) emitted by LHD under downcast airflow scenario in open stope. 3.4. Airborne dust dilution The generation and dispersion of dust due to muck sliding and loose rock fall inside an open stope have the potential to generate dust cloud, which in turn influence the line-of-sight LHD operation (Miner, 2022 ). Therefore, the particulates aerosolised due to muck sliding and loose rock fall inside the stope have been considered in this research. The airborne dust concentration was measured at remote LHD operator location in the mucking drive. The high-resolution concentration data obtained during 10 s muck sliding and loose rock fall inside the stope was analysed subsequently. The analysis of results presented in Fig. 9 revealed the peak concentrations of alveolic, thoracic and inhalable airborne dusts in the order 1439 µg/m 3 , 4961 µg/m 3 , and 8700 µg/m 3 , respectively. Moreover, Fig. 9 shows the dilution of alveolic, thoracic and inhalable dust clouds with time from peak concentration to baseline concentration by ventilation air (air velocity in the mucking drive: 0.7 m/s) at the remote operator location in the mucking drive. Though the concentration of finer dust (alveolic) is found to be low, the coarser (thoracic and inhalable) dusts can affect the visibility in the mucking drive and stope till they are cleared away by the airflow. The frequent sliding of blasted muck or falling of loose rocks inside the open stope may also increase the operation cycle time as the remote LHD operator has to wait for better visibility before sending the LHD inside the stope for line of sight mucking operation. From Fig. 9 , it may also be observed that the airborne dusts are diluted exponentially by the ventilation air. The empirical relations established relating the clearance of airborne dust generated due to muck sliding and loose rock fall inside the open stope at operator location with time are given below. These equations may be useful for predicting the dilution time for dusts of different sizes in open stope mucking drive. y 7 = 1852.3e − 0.023x (7) y 8 = 5818.6e − 0.024x (8) y 9 = 9616.9e − 0.027x (9) where y 7 , y 8 , and y 9 , are concentration (µg/m 3 ) of alveolic, thoracic, and inhalable dust, respectively. ‘x’ is the time (s) 4. Limitations And Scope Of Further Studies This paper presented the results of a study aimed at identifying the dust pollution hazard and investigating the concentration and dispersion of dust generated due to line-of-sight remotely operated LHD in an open stope having dry blasted muck under downcast airflow. The dust dispersion is assumed homogenous in the dust monitoring locations. As the analysis is based on engineering sampling, the measured dust concentrations should not be construed as regular miners’/operators' exposure values. However, the outcome of this study may aid in dust control of similar mining operations and environment. There is lots of scope for furthering this study. Automation in mucking and loading operations can help in enhancing safety and productivity under difficult situations (Swart et al., 2002 ). It is well known that the operation of tele-remote LHD can be controlled from the surface control room, which facilitates the operator to operate the LHD at the earliest after shift allocation and runs the LHD till the end of 8-hour shift (Hwang et al., 1999 ). Future studies may consider full automation of LHD operation in a defined layout in mines or sections of mines, which eliminates the physical presence of remote operators in mucking areas (Tampier et al., 2021 ). Moreover, mine ventilation is an integral part of dust control strategies to dilute the respirable dust in working areas in FMUMM (Cecala et al., 2005 ). The primary airflow direction in the long-hole open stopes plays an important role in diluting and dispersing the high dust concentration. The use of battery-operated LHDs may create better working environment by achieving zero-emission of DPM and exhaust gases in mines. However, future studies may be focused on mineral dust generation and dispersion due mining operations in FMUMM (Jang and Topal, 2020 ). The knowledge regarding the average size of dust particles propagated in underground mine workplace will be vital in selecting and implementing appropriate dust control strategy and equip the miners with knowledge about various airborne dust hazards, which threaten the miners’ health due to different mining operations. 5. Conclusions This study emphasizes on airborne dust hazard identification for line-of-sight remote LHD operators during open stope mucking in mechanised underground lead-zinc ore mine. It involves measurement and analysis of harmful airborne dust generated due to line-of-sight remote LHD operation in an open stope under downcast airflow. The conclusions drawn from the study are outlined as follows: a) The particulates above 10 µm size, which are not in respirable size range, share 25–32% and the submicron particles (i.e., ≤ 1 µm) occupy 3.0% in the downstream total airborne dust (TAD) at the remote operator location in the mucking drive. b) The percent proportions of occupational dust types, such as alveolic and thoracic dusts, in downstream airborne dust at the remote operator location are determined 25.1% and 74.2%, respectively. Empirical relations have also been developed for predicting the proportions of alveolic and thoracic particulates in the downstream TAD. c) Differential concentrations of downstream particulate matter for the size ranges of 15.0–20.0 µm, 10.0–15.0 µm 5.0–10.0 µm, and 0.23-5.0 µm are analysed, and their correlations with total airborne dust have been developed. Tele-operated LHD is recommended to avoid LHD operator’s exposure to respirable dust in mucking areas. d) Airborne dust generated due to rock fragments sliding and loose rock fall inside the open stope is estimated. Moreover, dilution of alveolic, thoracic and inhalable dusts at the remote operator location in mucking drive is analysed. For remote LHD operators, continuous wearing of dust mask is recommended to reduce their dust inhalation exposure during mucking. Declarations Acknowledgements The authors are grateful to the Kayad Mine, HZL of Vedanta Ltd. for giving permission to conduct the field study for this research. Ethical approval: Not applicable. This research does not involve the use of any animal or human data or tissue. Consent to Participate: Not applicable. Consent to Publish: Not applicable. Author Contributions: B Paluchamy: Investigation, Methodology, Software, Data curation, Formal analysis, Writing – original draft. Devi Prasad Mishra: Conceptualization, Visualization, Methodology, Supervision, Writing – review & editing. Funding: The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Competing interests: The authors have no relevant financial or non-financial interests to disclose. Availability of data and materials: All relevant data generated during the study are included in the article. References Ambastha SK, Haritash AK (2022) Emission of respirable dust from stone quarrying, potential health effects, and its management. Environ Sci Pollut Res 29:6670–6677. https://doi.org/10.1007/s11356-021-16079-4 Belle B (2018) How relevant are engineering samples in the management of personal dust exposure ? 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Earth Environ Sci 773. https://doi.org/10.1088/1755-1315/773/1/012077 NIOSH (2002) Health effects of occupational exposure to respirable crystalline silica [WWW Document]. DHHS Publ. No. 2002–129. URL https://www.cdc.gov/niosh/docs/2002-129/pdfs/2002-129.pdf?id=10.26616/NIOSHPUB2002129 Paluchamy B, Mishra DP (2021) Airborne dust generation and dispersion profiles due to loaded LPDT haulage in decline of a highly mechanized underground lead – zinc ore mine. Environ Technol Innov 24:101908. https://doi.org/10.1016/j.eti.2021.101908 Paluchamy B, Mishra DP, Panigrahi DC (2021) Airborne respirable dust in fully mechanised underground metalliferous mines – Generation, health impacts and control measures for cleaner production. J Clean Prod 296. https://doi.org/10.1016/j.jclepro.2021.126524 Patra AK, Gautam S, Kumar P, Kumar A, Gautam S, Kumar P (2016) Emissions and human health impact of particulate matter from surface mining operation — A review. Environ Technol Innov 5:233–249. https://doi.org/10.1016/j.eti.2016.04.002 Ping C, Guang X, Fubao Z, Benjamin M, Abishek S (2019) Comparison of underground mine DPM simulation using discrete phase and continuous phase models. Process Saf Environ Prot 127:45–55. https://doi.org/10.1016/j.psep.2019.04.027 Saarikoski S, Teinilä K, Timonen H, Aurela M, Laaksovirta T, Reyes F, Vásques Y, Oyola P, Artaxo P, Pennanen AS, Junttila S, Linnainmaa M, Salonen RO, Hillamo R (2018) Particulate matter characteristics, dynamics, and sources in an underground mine. Aerosol Sci Technol 52:114–122. https://doi.org/10.1080/02786826.2017.1384788 Schunnesson H, Gustafson A, Kumar U (2001) Performance of Automated LHD machines:A Review Swart C, Miller F, Corbeil PA, Falmagne V, St-Arnaud L (2002) Vehicle automation in production environments.J. South African Inst. Min. Metall.139–144 Tampier C, Mascar M, Ruiz-del-solar J (2021) Autonomous loading system for Load-Haul-Dump (LHD) machines used in underground mining.Appl. Sci.11 WHO (1999) Hazard prevention and control in the work environment: Airborne dust. WHO (World Heal. Organ. 96 WSN (2012) Safe Operation of Remote Controlled Equipment Zheng J, Huynh T, Gasparon M, Ng J, Noller B (2013) Human health risk assessment of lead from mining activities at semi-arid locations in the context of total lead exposure. Environ Sci Pollut Res 20:8404–8416. https://doi.org/10.1007/s11356-013-2145-4 Zilaout H, Vlaanderen J, Houba R, Kromhout H (2017) 15 years of monitoring occupational exposure to respirable dust and quartz within the European industrial minerals sector. Int J Hyg Environ Health 220:810–819. https://doi.org/10.1016/j.ijheh.2017.03.010 Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Major Revision 30 Mar, 2022 Reviews received at journal 15 Mar, 2022 Reviewers invited by journal 15 Mar, 2022 Editor assigned by journal 02 Mar, 2022 First submitted to journal 23 Feb, 2022 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1390084","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":90917442,"identity":"5f104463-1795-4351-a187-885c8726fb8b","order_by":0,"name":"B Paluchamy","email":"","orcid":"","institution":"IIT (ISM): Indian Institute of Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"B","middleName":"","lastName":"Paluchamy","suffix":""},{"id":90917443,"identity":"a48c9d77-708e-45c9-9313-4f64c3d1f8a7","order_by":1,"name":"Devi Prasad Mishra","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3UlEQVRIiWNgGAWjYDCCA0DE2MDAwM8MJBMQgkRokWxmbGwgWgsDSIvBATBFBOC73Z148OeOe/LGx5nbHzz4s42Bv/0A4+ECPFok75zdcJj3TLHhtsNAhyW23WaQOJPAcHgGHi0GN3I3HGZsS2CEaGm4zcBwg4HhMA8BLQd/tiXYbwZ7/89tBnlitBzgbUtI3MAM0sJ2GyhCQAvEL20JyTOADpsB9AuP4ZnEBrxa+G73bv4IdJhtf//xBx9//LktJ3f88OHP+LQwSKDxeRgIxg+6llEwCkbBKBgFGAAAgn1c4OhnWBcAAAAASUVORK5CYII=","orcid":"","institution":"IIT (ISM): Indian Institute of Technology","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Devi","middleName":"Prasad","lastName":"Mishra","suffix":""}],"badges":[],"createdAt":"2022-02-23 19:58:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1390084/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1390084/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":19344585,"identity":"19e3196c-dfad-4d91-917b-a5fcf9ff16af","added_by":"auto","created_at":"2022-03-17 18:39:47","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":615869,"visible":true,"origin":"","legend":"\u003cp\u003eA typical line-of-sight remote LHD mucking operation in an open stope\u003c/p\u003e","description":"","filename":"fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/bfb7e75634b28d580bbcbe32.png"},{"id":19344706,"identity":"c5aed0f3-1fec-4fb9-a248-062c23e58743","added_by":"auto","created_at":"2022-03-17 18:42:47","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":423524,"visible":true,"origin":"","legend":"\u003cp\u003eLocation of KLZM and LVS layout depicting declines, raises, and underground levels\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/45c4d62aa1c7cfe0f76b2a4f.png"},{"id":19344578,"identity":"1a886c0c-5e5f-4d5a-bd1c-b56fcd1948a9","added_by":"auto","created_at":"2022-03-17 18:39:47","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":416032,"visible":true,"origin":"","legend":"\u003cp\u003eLayout illustrating a typical primary airflow scenario in open stope (created using Ventsim software)\u003c/p\u003e","description":"","filename":"fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/147215e1298b1c165b38f4bb.png"},{"id":19344580,"identity":"86fb057e-93be-4f61-9c72-f146719c4924","added_by":"auto","created_at":"2022-03-17 18:39:47","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":186560,"visible":true,"origin":"","legend":"\u003cp\u003e\tLayout depicting downcast-airflow and dust monitor location in the stope\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"fig4.png","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/42ec7132bdf91587f70d2d62.png"},{"id":19344581,"identity":"ba1529b8-3573-43d0-95a1-26d8a07a52ac","added_by":"auto","created_at":"2022-03-17 18:39:47","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":186037,"visible":true,"origin":"","legend":"\u003cp\u003eCumulative dust dispersion profiles at the line-of-sight remote LHD operator location\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"fig5.png","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/68bbcbd675a26d69429b801b.png"},{"id":19344582,"identity":"303c022b-101e-42cc-9a70-42f595ad2699","added_by":"auto","created_at":"2022-03-17 18:39:47","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":152886,"visible":true,"origin":"","legend":"\u003cp\u003eProportions of alveolic and thoracic dust types in inhalable dust concentration\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"fig6.png","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/12cd56f735bf6253447424d7.png"},{"id":19344586,"identity":"73aa9563-ed5b-42af-b3e4-cfdad86d43a7","added_by":"auto","created_at":"2022-03-17 18:39:47","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":106997,"visible":true,"origin":"","legend":"\u003cp\u003eConcentrations of alveolic and thoracic dusts in downstream inhalable dust\u003c/p\u003e","description":"","filename":"fig7.png","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/81268dbc7246c7d4b7dc8a7e.png"},{"id":19344579,"identity":"a4b82a62-706f-4e7d-a110-16b3936a5264","added_by":"auto","created_at":"2022-03-17 18:39:47","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":101555,"visible":true,"origin":"","legend":"\u003cp\u003eDifferential dust concentration profiles at remote LHD operator location\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"fig8.png","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/065541690a62fceafe1a8cd6.png"},{"id":19344583,"identity":"b2eb13a9-9410-47ea-a3b5-1ccee95b4d2b","added_by":"auto","created_at":"2022-03-17 18:39:47","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":65441,"visible":true,"origin":"","legend":"\u003cp\u003eDilution of airborne dust with time at remote LHD operator location\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"fig9.png","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/3caf03f9a00c8b13ab867d87.png"},{"id":19344707,"identity":"feebf81e-41fa-4d84-ab23-83ad8bdfc094","added_by":"auto","created_at":"2022-03-17 18:42:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":980710,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1390084/v1/5663b93a-5f9a-43ba-95a2-6565c87d7b00.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003eDust pollution hazard and harmful airborne dust exposure assessment for remote LHD operator in underground lead-zinc ore mine open stope\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eUnderground mining is the process by which the naturally occurring mineral deposits are extracted from underground by employing various mining methods (supported, unsupported and caving methods) (Hamrin, \u003cspan class=\"CitationRef\"\u003e2001\u003c/span\u003e). The mining processes, such as drilling, blasting, mucking, hauling, crushing, etc. inherently produce particulate matter (PM) due to breaking down of rocks. The primary dust (generated due to mechanical forces), and secondary dust (airborne due to aerosolisation) are transported to other workings and non-working areas along with ventilating air current in underground mines and influence the downstream airborne dust concentration (Paluchamy et al., \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e). In day-to-day mining operations, miners are exposed to various airborne contaminants, which may cause occupational respiratory diseases in coal and metalliferous mines (Ambastha and Haritash, \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e; Chen et al., \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e; Zilaout et al., \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e). The significant amount of dust generated due to production blasting is diluted by ventilating air, and a large quantity of dust is trapped under the blasted rock fragments in stopes (Chekan et al., \u003cspan class=\"CitationRef\"\u003e2004\u003c/span\u003e). If precautions such as wetting of rock fragments before mucking are not taken, the trapped dust poses an airborne dust hazard. Nevertheless, wetting of muck pile in stopes is not easy as it has inherent difficulties, such as requirement of a safe location for the person to stand, water spray reachability, duration of spray, spray water penetration into the muck, etc., resulting abundance of dry dust in open stopes (Chekan et al., \u003cspan class=\"CitationRef\"\u003e2001\u003c/span\u003e). Identification of hazards is crucial in the risk assessment process, as the new operation could bring unidentified hazards in the workplace. This research paper focuses on dust pollution hazard identification during a typical remote LHD mucking in underground metalliferous mine open stopes. The analysis results can aid in development of low-cost sensor-based dust monitoring and control system for mechanised underground mines.\u003c/p\u003e\n\u003cp\u003eMucking and hauling of un-wetted blasted rock fragments with load haul dumpers (LHDs) in underground metalliferous mine development headings and stopes liberate large amounts of particulates. LHD is a rubber-tired, low-profile front-end loader used in underground mines or tunnels to load the fragmented/blasted rocks in its scoop, haul them to an unloading point and dump the muck. LHDs have environmentally protected cabins for protecting the operator from dust and heat. However, the environment inside the cabin depends on many parameters that include design and operational factors (Cecala et al., \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e). LHDs are commonly operated in unsupported areas in underground metalliferous mines using line-of-sight remote control (i.e., the operator operates the machine under his direct eyesight using remote) to enhance the operator safety and productivity (Schunnesson et al., \u003cspan class=\"CitationRef\"\u003e2001\u003c/span\u003e). The line-of-sight remote LHD operation has several advantages that include reliable operation, no network delay, low investment, etc. However, the line-of-sight remote controlled LHD operation range is limited within the operator\u0026apos;s visual range and cannot be as fast as an on-board operator. The LHD operator usually stands and operates the LHD remotely from a safe distance of 10 to 40 m in line-of-sight of stope corner (Swart et al., \u003cspan class=\"CitationRef\"\u003e2002\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eDuring line-of-sight remote LHD mucking, the LHD operator stays inside the LHD cabin until he reaches near stope brow, a safe place where he can come out of the cabin with a remote and send the LHD inside the stope to draw the muck (WSN, \u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e). The significant steps involved in line-of-sight remote LHD mucking is specified in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eThe LHD cabin door is required to be opened and closed, thereby allows the outside dusty air enter the cabin two times in a regular cycle. Hence, there is a possibility that the remote LHD operator can directly be exposed to harmful mineral dust, heat, diesel engine exhaust fumes, and DPM (Du et al., \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e; Ping et al., \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e). Figure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ea illustrates the top view of a typical open stope while the LHD drawing blasted muck inside the stope. Figure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb shows the typical remote operator location (e.g., safe sides in the mucking drive, specified size x-cut for operator to stand and operate the LHD), with the visual range of LHD. In the mucking drive, the loaded LHD is manually operated to reach the unloading point (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ec).\u003c/p\u003e\n\u003cp\u003eThe generation and distribution of dust in underground metalliferous mines can vary with various mining activities and ore properties. Limited studies have been conducted on mineral dust generation in mechanised underground metalliferous mines (Biffi and Belle, \u003cspan class=\"CitationRef\"\u003e2003\u003c/span\u003e; Saarikoski et al., \u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e). Studies have confirmed that the adverse health effects of airborne dust depends on size (including nano size particles) and concentration of dust, toxic substance/elements present in the dust, and miners\u0026rsquo; exposure to the dust (NIOSH, \u003cspan class=\"CitationRef\"\u003e2002\u003c/span\u003e; Zheng et al., \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e). Few researches have been conducted on dilution of exhaust fumes generated during LHD mucking in stopes (Nakaryakov and Grishin, \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, past studies did not assess the generation and dispersion profiles of dust based on particle size, which is very important from the occupational health hazard point of view and for devising appropriate dust control strategies in underground metalliferous mines. No study has been conducted on airborne dust generation and dispersion in open-stopes of mechanised underground metalliferous mines. Use of electric LHDs though eliminates diesel exhaust fumes and DPM hazard in underground working environment, the mineral dusts generated owing to their use could pose health hazard. Keeping this in mind, this study focuses on the identification of dust pollution hazard and assesses the airborne dust generated due to line-of-sight remote LHD (17 tonne capacity) mucking in underground lead-zinc ore mine open stopes under downcast airflow. Moreover, it analyses the concentrations of airborne dust in upstream (baseline) and downstream sides of the working stope.\u003c/p\u003e"},{"header":"2. Materials And Methods","content":"\u003cdiv class=\"Section2\" id=\"Sec3\"\u003e\n \u003ch2\u003e2.1. Approach\u003c/h2\u003e\n \u003cp\u003eIn this study, the dust pollution hazard for remote LHD operator engaged in mucking in open stopes is identified by simulating different working scenarios. In order to achieve the study objectives, the important factors, such as site selection, field monitoring and procedures followed during the field study, data analysis and empirical relation development are outlined. Airborne particulates sampling is conducted at the study site using real-time aerosol spectrometers to quantify the harmful airborne dusts. Furthermore, relevant ventilation parameters, such as dry-bulb temperature (DBT), wet-bulb temperature (WBT), relative humidity (RH), equipment movement, and drive dimensions are measured to examine the behaviour and relative size distribution of dusts.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec4\"\u003e\n \u003ch2\u003e2.2. Site selection\u003c/h2\u003e\n \u003cp\u003eThe study site was selected based on the level of mechanisation implemented in various mining operations, accessibility, and safe installation of dust monitoring equipment. Kayad lead-zinc mine (KLZM) of Hindustan Zinc Limited (HZL), an active and fully mechanised underground lead-zinc mine in India, was selected for the field study. The KLZM is located in Kayad village, Ajmer city of Rajasthan state as shown in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. The mine is relatively shallow in depth. The main access to the mine is through the main decline. The surface level of the mine is 487 mRL. The mine decline is of 5.50 m \u0026times; 5.00 m (W \u0026times; H) cross-section with arched roof and gradient 1 in 7. The main decline split into north decline and south decline at 412 mRL (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The study was conducted at 375 mRL in the north section. A working longhole open stope was identified in 375\u0026ndash;400 mRL for subsequent field monitoring.\u003c/p\u003e\n \u003cp\u003eBoundary and exhaust ventilation system is implemented to fulfil the ventilation requirement of the mine. All the mine ventilation fan speeds are regulated by variable frequency drive (VFD).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec5\"\u003e\n \u003ch2\u003e2.3. Data collection\u003c/h2\u003e\n \u003cp\u003eThe mass concentration and size distribution of airborne dust were monitored using Grimm aerosol spectrometers (model 1.108) with necessary field measurement accessories. The percentage of respirable dust is a function of dust particle size. Recent studies showed that finer dust particles have more impact on human lungs in a typical mining environment (Gautam et al., \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e; Patra et al., \u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e). Therefore, the aerosol spectrometers which can classify up to 15 size ranges starting from 0.23 to 20 micron were used in this study. The aerosol spectrometers also classify the airborne dusts in terms of respirable, thoracic and inhalable dust types (Grimm, \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e). \u0026lsquo;Mass Distribution\u0026rsquo; option was selected in operational mode, and the rest of the values kept default in this study.\u003c/p\u003e\n \u003cp\u003eThe average airflow velocity in the study area was measured using a vane anemometer (Micon-2 dial). The temperature and relative humidity were measured using a humidity meter (Lutron: PHB-318) during the LHD movement in the study area. The dust monitors were placed near the breathing zone at about 1.6 m height beside the mucking drive wall to prevent their damage from moving LHD. Engineering sampling (Belle, \u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e) was adopted for measuring the dust generation and dispersion due to line-of-sight remote LHD mucking in the open stope. Here, engineering sample represents the airborne dust sample collected to characterise the dust emission source when the particular engineering activity (e.g., LHD mucking in this case) is taking place. Moreover, LHD entry and exit times in the monitoring area were recorded.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. Results And Discussion","content":"\u003cdiv class=\"Section2\" id=\"Sec7\"\u003e\n \u003ch2\u003e3.1. Dust pollution hazard identification for remote LHD operator in open stopes\u003c/h2\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e shows a layout illustrating the typical airflow scenarios in an open stope during line-of-sight remote LHD mucking. A well-planned ventilation network will have the airflow direction as marked in the drilling level (a-b-c-g) and mucking level (d-e-f-c-g) drives (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ea). As depicted in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ea, the remote LHD operator location in the mucking level drive is ventilated by intake air from decline, and the stope exhaust air is directed to the return drive in drill level. However, the other two scenarios illustrate that the remote LHD operator location is contaminated by stope exhaust air, which contains harmful diesel exhaust and airborne mineral dust due to downcast airflow (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003eb) and recirculation (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ec) of air in the working stope, respectively. The direction of primary airflow in the stope as depicted in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003eb, \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ec may be caused by unplanned obstructions in the airways, opening or closing of ventilation doors, connecting development drives in different working levels, opening or backfilling of stopes, and unexpected stoppage of main fans in mechanised underground metalliferous mines.\u003c/p\u003e\n \u003cp\u003eBased on the simulation results for a typical remote LHD mucking scenarios, these undesired downcast and recirculation of airflow in open stopes may lead to the exposure of remote LHD operator to harmful airborne contaminants, such as airborne mineral dust, diesel engine exhaust gases, and diesel particulate matter (DPM) during line-of-sight remote LHD mucking. This study aimed to investigate the concentration of harmful airborne dusts at remote operator location for the two scenarios shown in Figs. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003eb, \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ec in a highly mechanised underground metalliferous mine. However, a working stope having air recirculation scenario (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ec) was not found during the field study in the mine.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec8\"\u003e\n \u003ch2\u003e3.2. Line-of-sight remote LHD mucking operations in KLZM\u003c/h2\u003e\n \u003cp\u003eCommonly, LHDs are involved in mucking of blasted muck or rock fragments from the working face and hauling to unloading points, such as truck or dump stockpile (DSP), and loading and hauling material for backfilling in KLZM. The shift in-charges and LHD operators provided the preliminary information about dust flow patterns (e.g., downcast and upcast airflow) in production stopes. Usually, the dust generated by the mucking operation does not affect the operator during upcast airflow (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ea). Hence, the downcast-airflow scenario in a working stope in North section of the mine was considered for assessment of harmful airborne dust at remote LHD operator location (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). The results of airborne dust analysis at remote operator location due to mucking in the open stope under downcast-airflow is presented subsequently. Figure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e illustrates the variation of dust concentration in mucking level drive due to remote LHD mucking in the stope under downcast-airflow. The LHD operator adjusted the distance between the mucking point (i.e., remote LHD in stope) and his location between 20 to 50 m depending upon the visibility and safe place during line-of-site remote LHD operation.\u003c/p\u003e\n \u003cp\u003eThe average velocity of airflow at monitoring location in the drive was measured 0.7 m/s. The drive was of 5 m\u0026times;4.5 m cross-section with arched roof, over break due to earlier down-level stopes, and wetted rock surfaces (sides and floor). The dust monitor was placed at a distance of 45 m from the dust source (i.e., LHD mucking) at a height of about 1.6 m in side of the mucking drive (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). Moreover, the necessary distance was set aside for the generated dust in the stope to mix with mine air before reaching the dust monitor location. The DBT, RH, O\u003csub\u003e2\u003c/sub\u003e and CO concentrations in the dust monitoring location during mucking were measured in the range of 28.5\u0026ndash;30.5\u0026deg;C, 82\u0026thinsp;\u0026minus;\u0026thinsp;77%, 20.6\u0026ndash;20.9%, and 5\u0026ndash;10 ppm, respectively. The general statistics and regression analysis of airborne dust measured during the field study have been summarised in the following section.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec9\"\u003e\n \u003ch2\u003e3.3. Assessment of airborne dust\u003c/h2\u003e\n \u003cp\u003eThe average concentration of total airborne dust (TAD) in upstream (i.e., baseline) and downstream side at the remote operator location are estimated 311\u0026thinsp;\u0026plusmn;\u0026thinsp;246 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e and 6210\u0026thinsp;\u0026plusmn;\u0026thinsp;2690 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e, respectively (number of readings, N\u0026thinsp;=\u0026thinsp;10 cycle). During the field study the blasted muck was in dry condition. Normal operating procedures at mines do require wetting of the muck piles prior to loading. However, the longhole-open stoping method of mining can make wetting of the blasted muck in stopes difficult at times (Chekan et al., \u003cspan class=\"CitationRef\"\u003e2001\u003c/span\u003e). Figure \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e presents the cumulative dust concentrations and percent proportions of \u0026le;\u0026thinsp;20 \u0026micro;m, \u0026le;\u0026thinsp;15 \u0026micro;m, \u0026le;\u0026thinsp;10 \u0026micro;m, \u0026le;\u0026thinsp;5 \u0026micro;m, and \u0026le;\u0026thinsp;1 \u0026micro;m size dusts in TAD. The analysis of particulates revealed the proportion of \u0026le;\u0026thinsp;20 \u0026micro;m, \u0026le;\u0026thinsp;15 \u0026micro;m, \u0026le;\u0026thinsp;10 \u0026micro;m, \u0026le;\u0026thinsp;5 \u0026micro;m, and \u0026le;\u0026thinsp;1 \u0026micro;m dusts in downstream TAD in the ranges of 89.4\u0026ndash;100%, 84.0-95.2%, 67.7\u0026ndash;75.2%, 24.8\u0026ndash;39.3%, 1.6\u0026ndash;8.6%, respectively.\u003c/p\u003e\n \u003cp\u003eIn Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e, it is evident that the dust particles greater than 10 \u0026micro;m size, which is not in respirable range (DGMS, \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e), constitute 29.7% and remaining\u0026thinsp;\u0026le;\u0026thinsp;10 \u0026micro;m dusts share 71.3% in the downstream TAD. Moreover, the percent proportion of \u0026le;\u0026thinsp;5 \u0026micro;m and \u0026le;\u0026thinsp;1 \u0026micro;m in the downstream TAD are estimated 28.5% and 3.0%, respectively. Another study by the authors in a decline of the same mine indicated the percent proportions of 6% and 0.5% for \u0026le;\u0026thinsp;5 \u0026micro;m and \u0026le;\u0026thinsp;1 \u0026micro;m, respectively in downstream TAD generated due to loaded LPDT travelling, which are much lower than in stope mucking areas (Paluchamy and Mishra, \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e). Nevertheless, the air velocity in the decline was higher (3 m/s) than the stope mucking drive (0.7 m/s). The low air velocity in the mucking drive might have facilitated quick settling of the coarser particles before reaching the aerosol monitor. Moreover, the air velocity inside the stope is lower than the mucking drive due to larger void space in the stope.\u003c/p\u003e\n \u003cp\u003eThe airborne dust was also analysed in terms of occupational dust types, such as alveolic and thoracic (CEN, 1993). The percent proportions of alveolic and thoracic dusts in respective inhalable dust concentrations of upstream and downstream sides are shown in Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e.\u003c/p\u003e\n \u003cp\u003eThe downstream concentration of inhalable dust at remote operator location in the mucking drive was measured in the range of 2192\u0026ndash;10433 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e. From Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e, it may be observed that the proportions of alveolic (48.9%) and thoracic (84.6%) dusts in the upstream side are higher than the respective dust types (i.e., 25.1% alveolic, and 74.2% thoracic) in downstream side. However, upstream inhalable dust concentration was found in the range of 93\u0026ndash;759 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e, which is due to dust concentration in declines as the North decline air serves as one of the primary intakes of the stope. Studies have confirmed that alveolic particulates fraction is the most hazardous as they penetrate beyond the terminal bronchioles into the gas-exchange region of the lungs (WHO, \u003cspan class=\"CitationRef\"\u003e1999\u003c/span\u003e). Moreover, the dust capturing efficiency of wet suppression system for respirable dust is lesser than the coarser particles. Though ventilation is one of the effective means of diluting respirable dust in stopes, wetting the blasted muck is of paramount importance to prevent the dust becoming airborne in stope (Chekan et al., \u003cspan class=\"CitationRef\"\u003e2001\u003c/span\u003e). Further analysis of downstream airborne dust concentration (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e) led to the establishment of following linear empirical relationships between the alveolic, thoracic and inhalable dust concentrations:\u003c/p\u003e\n \u003cp\u003ey\u003csub\u003e1\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.2039x\u0026thinsp;+\u0026thinsp;290.53 (1)\u003c/p\u003e\n \u003cp\u003ey\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.7417x\u0026thinsp;+\u0026thinsp;2.7998 (2)\u003c/p\u003e\n \u003cp\u003ewhere y\u003csub\u003e1\u003c/sub\u003e and y\u003csub\u003e2\u003c/sub\u003e are concentrations of alveolic and thoracic dust types in inhalable dust, and x is inhalable dust concentration in downstream. These relationships will be useful for assessing the concentration of alveolic dust from the known total airborne dust concentration in similar working areas.\u003c/p\u003e\n \u003cp\u003eThe differential dust concentrations of various size ranges plotted against the total airborne dust (TAD) in Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e depict that the concentrations of dust sizes 15.0\u0026ndash;20.0 \u0026micro;m, 10.0\u0026ndash;15.0 \u0026micro;m 5.0\u0026ndash;10.0 \u0026micro;m, and 0.23.0\u0026ndash;5.0 \u0026micro;m linearly increase with increase in the concentration of TAD in downstream air. Differential concentration of downstream airborne dust (DS) for the size ranges of 15.0\u0026ndash;20.0 \u0026micro;m,10.0\u0026ndash;15.0 \u0026micro;m 5.0\u0026ndash;10.0 \u0026micro;m, and 0.23-5.0 \u0026micro;m, was analysed in the range of 0-707 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e, 315\u0026ndash;2205 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e, 786\u0026ndash;4577 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e, and 862\u0026ndash;2756 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e, respectively. The respirable dust of \u0026le;\u0026thinsp;5 \u0026micro;m size is considered to be more hazardous. The large variation in concentration (i.e., 862\u0026ndash;2756 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e) of 0.23-5.0 \u0026micro;m size dust in the downstream air may be attributed to the variation in LHD bucket filling and muck sliding in different mucking cycle. Moreover, the analysis revealed better correlations for the 10.0\u0026ndash;15.0 \u0026micro;m and 5.0\u0026ndash;10.0 \u0026micro;m (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.95 and 0.98) size ranges than the coarser sizes (i.e., 15.0\u0026ndash;20.0 \u0026micro;m) (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.76) with TAD. Empirical correlations established for different particle size ranges are given below.\u003c/p\u003e\n \u003cp\u003ey\u003csub\u003e3\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.0689x \u0026minus;\u0026thinsp;82.374 (3)\u003c/p\u003e\n \u003cp\u003ey\u003csub\u003e4\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.2387x \u0026minus;\u0026thinsp;299.76 (4)\u003c/p\u003e\n \u003cp\u003ey\u003csub\u003e5\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.4664x \u0026minus;\u0026thinsp;237.74 (5)\u003c/p\u003e \u003cp\u003ey\u003csub\u003e6\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.2352x\u0026thinsp;+\u0026thinsp;310.38 (6)\u003c/p\u003e\n \u003cp\u003ewhere y\u003csub\u003e3\u003c/sub\u003e, y\u003csub\u003e4\u003c/sub\u003e, y\u003csub\u003e5\u003c/sub\u003e, and y\u003csub\u003e6\u003c/sub\u003e are dust concentrations of the size ranges of 15.0\u0026ndash;20.0 \u0026micro;m, 10.0\u0026ndash;15.0 \u0026micro;m 5.0\u0026ndash;10.0 \u0026micro;m, and 0.23.0\u0026ndash;5.0 \u0026micro;m, respectively. \u0026lsquo;x\u0026rsquo; is the concentration of TAD in downstream.\u003c/p\u003e\n \u003cp\u003eThe analysis of various particle sizes, such as finer and coarser particles in TAD, will facilitate the assessment of particles deposition in human respiratory tract (Patra et al., \u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e). Moreover, the aforementioned relationships established through this research will aid environmental monitoring and smart dust control through wireless sensor network (WSN) in mechanised underground mines (Muduli et al., \u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e). Apart from airborne dust exposure risk, the remote LHD operator may also be exposed to harmful exhaust gases and other sub-micron particulates, such as diesel particulate matter (DPM) emitted by LHD under downcast airflow scenario in open stope.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec10\"\u003e\n \u003ch2\u003e3.4. Airborne dust dilution\u003c/h2\u003e\n \u003cp\u003eThe generation and dispersion of dust due to muck sliding and loose rock fall inside an open stope have the potential to generate dust cloud, which in turn influence the line-of-sight LHD operation (Miner, \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e). Therefore, the particulates aerosolised due to muck sliding and loose rock fall inside the stope have been considered in this research. The airborne dust concentration was measured at remote LHD operator location in the mucking drive. The high-resolution concentration data obtained during 10 s muck sliding and loose rock fall inside the stope was analysed subsequently. The analysis of results presented in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e revealed the peak concentrations of alveolic, thoracic and inhalable airborne dusts in the order 1439 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e, 4961 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e, and 8700 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e, respectively. Moreover, Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e shows the dilution of alveolic, thoracic and inhalable dust clouds with time from peak concentration to baseline concentration by ventilation air (air velocity in the mucking drive: 0.7 m/s) at the remote operator location in the mucking drive. Though the concentration of finer dust (alveolic) is found to be low, the coarser (thoracic and inhalable) dusts can affect the visibility in the mucking drive and stope till they are cleared away by the airflow. The frequent sliding of blasted muck or falling of loose rocks inside the open stope may also increase the operation cycle time as the remote LHD operator has to wait for better visibility before sending the LHD inside the stope for line of sight mucking operation. From Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e, it may also be observed that the airborne dusts are diluted exponentially by the ventilation air. The empirical relations established relating the clearance of airborne dust generated due to muck sliding and loose rock fall inside the open stope at operator location with time are given below. These equations may be useful for predicting the dilution time for dusts of different sizes in open stope mucking drive.\u003c/p\u003e \u003cp\u003ey\u003csub\u003e7\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;1852.3e\u003csup\u003e\u0026minus;\u0026thinsp;0.023x\u003c/sup\u003e (7)\u003c/p\u003e \u003cp\u003ey\u003csub\u003e8\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;5818.6e\u003csup\u003e\u0026minus;\u0026thinsp;0.024x\u003c/sup\u003e (8)\u003c/p\u003e \u003cp\u003ey\u003csub\u003e9\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;9616.9e\u003csup\u003e\u0026minus;\u0026thinsp;0.027x\u003c/sup\u003e (9)\u003c/p\u003e\n \u003cp\u003ewhere y\u003csub\u003e7\u003c/sub\u003e, y\u003csub\u003e8\u003c/sub\u003e, and y\u003csub\u003e9\u003c/sub\u003e, are concentration (\u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e) of alveolic, thoracic, and inhalable dust, respectively. \u0026lsquo;x\u0026rsquo; is the time (s)\u003c/p\u003e\n\u003c/div\u003e"},{"header":"4. Limitations And Scope Of Further Studies","content":"\u003cp\u003eThis paper presented the results of a study aimed at identifying the dust pollution hazard and investigating the concentration and dispersion of dust generated due to line-of-sight remotely operated LHD in an open stope having dry blasted muck under downcast airflow. The dust dispersion is assumed homogenous in the dust monitoring locations. As the analysis is based on engineering sampling, the measured dust concentrations should not be construed as regular miners\u0026rsquo;/operators' exposure values. However, the outcome of this study may aid in dust control of similar mining operations and environment.\u003c/p\u003e \u003cp\u003eThere is lots of scope for furthering this study. Automation in mucking and loading operations can help in enhancing safety and productivity under difficult situations (Swart et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). It is well known that the operation of tele-remote LHD can be controlled from the surface control room, which facilitates the operator to operate the LHD at the earliest after shift allocation and runs the LHD till the end of 8-hour shift (Hwang et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). Future studies may consider full automation of LHD operation in a defined layout in mines or sections of mines, which eliminates the physical presence of remote operators in mucking areas (Tampier et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Moreover, mine ventilation is an integral part of dust control strategies to dilute the respirable dust in working areas in FMUMM (Cecala et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). The primary airflow direction in the long-hole open stopes plays an important role in diluting and dispersing the high dust concentration. The use of battery-operated LHDs may create better working environment by achieving zero-emission of DPM and exhaust gases in mines. However, future studies may be focused on mineral dust generation and dispersion due mining operations in FMUMM (Jang and Topal, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The knowledge regarding the average size of dust particles propagated in underground mine workplace will be vital in selecting and implementing appropriate dust control strategy and equip the miners with knowledge about various airborne dust hazards, which threaten the miners\u0026rsquo; health due to different mining operations.\u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThis study emphasizes on airborne dust hazard identification for line-of-sight remote LHD operators during open stope mucking in mechanised underground lead-zinc ore mine. It involves measurement and analysis of harmful airborne dust generated due to line-of-sight remote LHD operation in an open stope under downcast airflow. The conclusions drawn from the study are outlined as follows:\u003c/p\u003e\n\u003cp\u003ea) The particulates above 10 \u0026micro;m size, which are not in respirable size range, share 25\u0026ndash;32% and the submicron particles (i.e., \u0026le;\u0026thinsp;1 \u0026micro;m) occupy 3.0% in the downstream total airborne dust (TAD) at the remote operator location in the mucking drive.\u003c/p\u003e\n\u003cp\u003eb) The percent proportions of occupational dust types, such as alveolic and thoracic dusts, in downstream airborne dust at the remote operator location are determined 25.1% and 74.2%, respectively. Empirical relations have also been developed for predicting the proportions of alveolic and thoracic particulates in the downstream TAD.\u003c/p\u003e\u003cspan\u003e\n \u003cp\u003ec) Differential concentrations of downstream particulate matter for the size ranges of 15.0\u0026ndash;20.0 \u0026micro;m, 10.0\u0026ndash;15.0 \u0026micro;m 5.0\u0026ndash;10.0 \u0026micro;m, and 0.23-5.0 \u0026micro;m are analysed, and their correlations with total airborne dust have been developed. Tele-operated LHD is recommended to avoid LHD operator\u0026rsquo;s exposure to respirable dust in mucking areas.\u003c/p\u003e\n\u003c/span\u003e\u003cspan\u003e\n \u003cp\u003ed) Airborne dust generated due to rock fragments sliding and loose rock fall inside the open stope is estimated. Moreover, dilution of alveolic, thoracic and inhalable dusts at the remote operator location in mucking drive is analysed. For remote LHD operators, continuous wearing of dust mask is recommended to reduce their dust inhalation exposure during mucking.\u003c/p\u003e\n\u003c/span\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors are grateful to the Kayad Mine, HZL of Vedanta Ltd. for giving permission to conduct the field study for this research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval: \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable. This research does not involve the use of any animal or human data or tissue.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate: \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Publish: \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions: \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eB Paluchamy:\u003c/strong\u003e Investigation, Methodology, Software, Data curation, Formal analysis, Writing \u0026ndash; original draft.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDevi Prasad Mishra:\u003c/strong\u003e Conceptualization, Visualization, Methodology, Supervision, Writing \u0026ndash; review \u0026amp; editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding: \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests: \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials: \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll relevant data generated during the study are included in the article.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAmbastha SK, Haritash AK (2022) Emission of respirable dust from stone quarrying, potential health effects, and its management. 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Int J Hyg Environ Health 220:810\u0026ndash;819. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.ijheh.2017.03.010\u003c/span\u003e\u003cspan address=\"10.1016/j.ijheh.2017.03.010\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Dust pollution hazard, airborne dust, dust exposure, remote LHD operator, underground lead-zinc ore mine, underground mine environment, mines safety","lastPublishedDoi":"10.21203/rs.3.rs-1390084/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1390084/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eUnderground mines have several occupational hazards, including airborne dust generated from various mining operations. Line-of-sight remote LHD mucking is adopted to draw the blasted muck from unsupported stopes in underground metalliferous mines. Investigation on particulate matter (PM) at remote operator location is crucial for assessing the operator exposure and devising appropriate dust control measures. This paper identifies the potential dust pollution hazard for remote LHD operator by simulating different mucking scenarios in open stope. PM generated due to mucking in a long-hole open stope by line-of-sight remote LHD during downcast airflow are measured using real-time aerosol spectrometers. The particulates concentration at upstream and downstream of dust source are analysed for various particle sizes including occupational dust types, such as alveolic and thoracic. The study revealed that the airborne dust concentrations of ≤10 μm, ≤5 μm, and ≤1 μm sizes in downstream, near the operator location, are measured 71.3%, 28.5%, and 3.0%, respectively. Moreover, the alveoli and thoracic dust fractions, respectively are determined 25.1% and 74.2%, in downstream and 48.9%, and 84.6%, in upstream total airborne dust concentration (311±246 μg/m3). The differential concentrations of 15.0-20.0 µm, 10.0-15.0 µm 5.0-10.0 µm, and 0.23.0-5.0 µm are analysed, and empirical relations of these sizes in total airborne dust are established. Moreover, dilution of airborne dust at remote LHD operator location is studied. This study enhanced the understanding on exposure potential of harmful dust during remote LHD mucking in open stopes. Moreover, it emphasised adoption of tele-remote-operated LHD and automated mucking operation in open stopes.\u003c/p\u003e","manuscriptTitle":"Dust pollution hazard and harmful airborne dust exposure assessment for remote LHD operator in underground lead-zinc ore mine open stope","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-03-17 18:39:45","doi":"10.21203/rs.3.rs-1390084/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major Revision","date":"2022-03-30T16:53:55+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-03-15T12:26:15+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-03-15T10:16:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-03-02T05:58:18+00:00","index":"","fulltext":""},{"type":"submitted","content":"Environmental Science and Pollution Research","date":"2022-02-23T14:57:49+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"8b9a2e9a-2f3d-4fea-b052-3b8409d565d6","owner":[],"postedDate":"March 17th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2022-07-12T22:25:04+00:00","versionOfRecord":[],"versionCreatedAt":"2022-03-17 18:39:45","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1390084","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1390084","identity":"rs-1390084","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}