https://orcid.org/0000-0002-4799-364X
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ABSTRACT
Block caving is an efficient underground mining method for extracting massive and low-grade ore deposits, which are too deep for traditional open-pit mining. However, in the case of orebodies with uranium mineralization, the extraction of broken rock from drawpoints will bring harmful radon gas into working areas. Airborne diesel particulate matter and dust produced from mining activities also contribute to the emissions on the production level. Maintaining relatively negative pressure in the cave by installing exhaust fans is one of the most effective approaches to mitigate gas emission concerns. The selection of proper fan systems is highly related to airflow behavior within the cave. Due to the dynamic caving process and complex cave structure, estimation of cave airflow resistance through field studies is difficult. This study developed a 1:100 scaled experimental and numerical model to investigate the effects of cave parameters (cave porosity, particle size, and undercut structure) on airflow resistance under parallel fan conditions. Results showed that cave airflow resistance increases with decreasing cave porosity and particle size; cave airflow behavior is significantly affected by undercut drift closure and the use of additional fans. This study provides valuable information to optimize ventilation system design in block cave mines.
RÉSUMÉ
Le foudroyage par blocs est une méthode d’extraction souterraine efficace pour l’extraction de gisements de minerai de grande taille et de faible teneur, trop profonds pour les exploitations traditionnelles à ciel ouvert. Toutefois, dans le cas des gisements minéralisés à l’uranium, l’extraction de roches brisées à partir des points de soutirage entraînera l’introduction de gaz radon nocif dans les zones de travail. Les particules de diesel en suspension dans l’air (PDS) et la poussière provenant des activités minières contribuent également aux émissions au niveau de la production. Maintenir une pression relativement négative dans la caverne en installant des ventilateurs d’échappement est l’une des approches les plus efficaces pour atténuer les problémes d’émissions de gaz. La sélection des systémes de ventilation appropriés est fortement liée au comportement du flux d’air dans la caverne. En raison de ce processus d’exploitation dynamique et de la structure complexe des cavernes, il est difficile d’estimer la résistance du flux d’air des cavernes au moyen d’études sur le terrain. Cette étude a mis au point des modéles expérimentaux et numériques à l’échelle 1:100 pour examiner les effets des paramétres des cavernes (porosité des cavernes, taille des particules et structure de fond) sur la résistance du flux d’air dans des conditions de ventilation paralléles. Les résultats ont montré que la résistance au flux d’air des cavernes augmente avec une diminution de la porosité des cavernes et de la taille des particules ; le comportement du flux d’air des cavernes est significativement affecté par la fermeture de la galerie de fond et l’utilisation de ventilateurs supplémentaires. Cette étude fournit des informations précieuses pour optimiser la conception du systéme de ventilation dans les mines exploitées par blocs foudroyés.
DISCLOSURE STATEMENT
No potential conflict of interest was reported by the authors.
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Notes on contributors
Y. Pan
Y. Pan is a mining engineering PhD student at South Dakota Mines. His research interests include mine ventilation and explosives and blasting. He is an active member of the Society for Mining, Metallurgy & Exploration (SME) and the International Society of Explosives Engineers (ISEE) and serves as a student representative on the ISEE Board.
P. Tukkaraja
P. Tukkaraja is an Associate Professor of Mining Engineering and the Director of South Dakota MSHA State Grants Program at South Dakota Mines, USA. Dr Tukkaraja is also an ABET Program Evaluator, Qualified Professional (QP) Member of the Mining and Metallurgical Society of America (MMSA). He serves on the SME’s Underground Ventilation Committee (UVC) Executive Board. PT@sdsmt.edu
S. Jayaraman Sridharan
S. Jayaraman Sridharan is a research scientist at South Dakota Mines. During his PhD, he worked on a number of mine ventilation consultancy projects for the mining companies SAIL and MOIL. He recently completed his PhD dissertation. His research is primarily focused on solving mine ventilation problems using CFD and scale modeling.
A. Jha
A. Jha is a mining engineering PhD student at South Dakota Mines. His research interests include mine ventilation, machine learning, and GIS applications in mining. He is an active member of the Society for Mining, Metallurgy & Exploration (SME) and the International Society of Explosives Engineers (ISEE).