RACA Journal I May 2026 www. refrigerationandaircon. co. za 23
MINE VENTILATION FEATURE SERIES
QUANTIFYING THE UNSEEN
By Eamonn Ryan
Fugitive carbon gas emissions in deep-level gold mines.
mine ventilation
In a crucial presentation at the 2025 Mine Ventilation Society of South Africa( MVSSA) conference, Alan Cook, a seasoned consultant and director at Latona Consulting, unveiled findings from a baseline assessment of fugitive carbon gas emissions at a deep-level South African gold mine. His research not only quantifies the mine ' s contribution to greenhouse gases but also provides vital comparisons with emissions from coal and platinum operations, underscoring the global imperative for accurate monitoring and reporting.
Alan Cook brings a wealth of experience to this critical topic, with a B. Sc. in mining from Strathclyde University, a Masters from the School of Mining at Wits, and a distinguished career spanning Gencor, CSIR, Sasol and Atasco Consulting Group. He has undertaken extensive work in methane and other flammable gases across coal, gold and platinum mining, coupled with involvement in explosion investigations and major research projects, positioning him to address the complexities of fugitive emissions.
UNEARTHING THE INVISIBLE Cook reported as follows: The primary objective of this baseline assessment was to quantify fugitive carbon gas emissions – specifically, gases emanating directly from the mine ' s ventilation fans, distinct from emissions generated by electricity usage or surface diesel fleets. The goal was to establish a reliable baseline using direct sampling and gas analysis. This approach, while labour-intensive, provides precise data crucial for aligning with IPCC( Intergovernmental Panel on Climate Change) guidelines for greenhouse gas reporting and supporting sustainable mining practices. It also serves to inform ventilation management strategies, a topic of increasing relevance in the context of climate change.
The study focused on two main shafts, designated Shaft 1 and Shaft 2, each equipped with surface ventilation fans. Data collection involved a continuous 48-hour monitoring period at each shaft, conducted by three teams working eight-hour shifts. Physical gas samples were collected every 30 minutes, with increased frequency to 15-minute intervals post-blast to capture any significant effects from blasting fumes. This rigorous methodology yielded a substantial dataset of 127 samples per site, totaling 254 samples, providing a robust foundation for the baseline assessment. Background samples were also taken at the start and end of each shift, with the lowest background values used to calculate worst-case emissions.
Sample analysis was performed at Pelindaba using GCMS( Gas Chromatography-Mass Spectrometry), capable of detecting concentrations down to 50ppm( parts per million). For methane( CH4), which is often registered below this threshold, selected samples were re-analysed using PDHID( Photoionisation Detector with Hydrogen Flame Ionisation Detection) to achieve detection limits as low as 2ppm. Samples were collected using hand pumps to fill 500-millilitre flexible bags, with each bag meticulously numbered and timerecorded. Barometric pressure was also recorded on the surface to account for its potential influence on gas concentrations.
QUANTIFYING FUGITIVE EMISSIONS
The results for Shaft 1
Alan Cook, consultant and director at Latona Consulting.
showed CO2 concentrations varying, with an average around 800ppm, peaking at approximately 1 300ppm. After subtracting background levels, the CO2 attributed to the mining operation was about 150ppm.
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RACA Journal I May 2026 www. refrigerationandaircon. co. za 23