Аннотация
Underground mines are particularly hazardous environments where miners are exposed to toxic fumes and gases. To ensure safety, sufficient mine ventilation must be provided. Ventilation requirements should be estimated considering diesel equipment engine power, blasting fumes, gases, aerosols, dust, and the unit airflow needed. Diesel engines are the main sources of toxic gases (CO, CO₂, NOₓ, SO₂, hydrocarbons) and diesel particulate matter (DPM). DPM consists of elemental carbon (EC), organic carbon (OC), and various gases and aerosols produced by incomplete combustion. The relationship between EC and OC fractions in untreated exhaust depends on engine operating conditions, engine type, fuel composition, and other parameters [5]. Total carbon (TC) is calculated as the sum of EC and OC and typically represents about 80% of total DPM [6]. Only 5–10% of all DPM particles are larger than one micrometer in diameter [2]. The concentration of particulate matter smaller than 1 μm (PM₁) is commonly used as an indicator of DPM levels because this size range encompasses nearly all diesel particulate matter [5]. Mine ventilation, diesel emission rates, exhaust flow direction, and the geometry of drifts influence DPM concentrations and dispersion patterns. Mobile diesel equipment operators generally experience the highest exposure to DPM. The main objective of this study is to conduct experimental sampling and analysis of DPM exposure for an operator of a diesel-powered load–haul–dump (LHD) loader working in an active ore heading area. Experimental sampling of particulate matter (PM) concentrations was carried out using a RigzardPM Plus sampling instrument in an underground polymetallic mine. Sampling was conducted over a 12-minute period inside the open cabin of an R1700 LHD loader (engine model Cat® C11 ACERT, 241 kW, Tier 3/Stage IIIA equivalent engine) working at the active ore heading face. The average PM₁ concentration measured by the RigzardPM Plus was 655 μg/m³ at a mine ventilation air velocity of 0.7 m/s. The LHD loader operated over a 30-meter haulage distance with an approximate cycle time of 2 minutes. Based on the TC–PM₁ correlation (DPM) used in the NIOSH 5040 method, the corresponding TC concentration of 185 μg/m³ is very close to the Mine Safety and Health Administration (MSHA, 2008) DPM limit of 160 μg/m³, measured as total carbon. This indicates that auxiliary ventilation requires moderate improvement to ensure sufficient dilution of toxic fumes in the active ore heading area. The measurement results appear reliable and demonstrate the suitability of the RigzardPM Plus instrument for monitoring DPM concentrations, with strong potential for its validation in computational fluid dynamics (CFD) modelling of DPM dispersion underground. The planned CFD simulations will incorporate LHD loader positions and auxiliary ventilation configurations in the active ore heading area. The expected outcome of this work is improved auxiliary ventilation design and enhanced protection of mine workers’ health.