Development of a novel cartridge for expansive cement application to hard rock breakage

ABSTRACTExpansive cement (EC) is generally a slurry that it is poured into vertical holes for surface rock breakage applications. This paper describes the development of a novel cartridge for extending EC applications from gravity-filled vertical holes to horizontal, uptilted, and wet boreholes. Four cartridge prototypes were made from low-cost and readily available plastics using three-dimensional printers. The performance of each cartridge was investigated in unconfined rock slab tests. The polylactic acid (PLA) cartridge was found to be superior to the thermoplastic polyurethane, polyethylene terephthalate glycol, and acrylonitrile butadiene styrene cartridges. Through partial heat containment, the PLA cartridge accelerated the EC hydraulic reaction and shortened the onset of rock destruction by 30% relative to vertical, gravity-filled EC. Finally, rock breakage with EC was demonstrated in an underground mine using PLA cartridges. This novel type of cartridge could not only suit various applications beyond the scope of the current EC surface applications but also significantly improve the rock fracturing efficiency of EC.RÉSUMÉLe ciment expansif (EC) est généralement une boue que l’on verse dans des trous verticaux pour briser la roche en surface. Cet article décrit le développement d’une nouvelle cartouche permettant d’étendre les applications du ciment expansif des trous verticaux remplis par gravité aux trous de forage horizontaux, inclinés et humides. Quatre prototypes de cartouches ont été fabriqués à l’aide d’imprimantes tridimensionnelles à partir de plastiques peu coûteux et facilement disponibles. Les performances de chaque cartouche ont été étudiées lors d’essais en dalles rocheuses non confinées.La cartouche en acide polylactique (PLA, de l’anglais polylactic acid) s’est avérée supérieure aux cartouches en polyuréthane thermoplastique, en polyéthyléne téréphtalate glycol et en acrylonitrile butadiéne styréne. Grâce au confinement partiel de la chaleur, la cartouche PLA a accéléré la réaction hydraulique de l’EC et a raccourci le début de la destruction de la roche de 30 % par rapport à l’EC verticale remplie par gravité. Enfin, la rupture de la roche avec l’EC a été démontrée dans une mine souterraine à l’aide de cartouches en PLA. Ce nouveau type de cartouche pourrait non seulement convenir à diverses applications dépassant le cadre des applications actuelles de l’EC en surface, mais aussi améliorer de maniére significative l’efficacité de la fracturation de la roche par l’EC.KEYWORDS: Expansive cement (EC)Field applicationsLaboratory testsNon-explosive rock breakagePolylactic acid (PLA)Soundless chemical demolition agentsMOTS-CLÉS: acide polylactique (PLA)agents de démolitionciment expansif (EC)applications sur le terrainessais de laboratoirerupture de roche non explosif DISCLOSURE STATEMENTNo potential conflict of interest was reported by the author(s).REVIEW STATEMENTThis article was reviewed and approved for publication by the Maintenance, Engineering and Reliability Society of the Canadian Institute of Mining, Metallurgy and Petroleum.AUTHORSHIP CONTRIBUTION STATEMENTTuo Chen: Conceptualization, methodology, formal analysis, investigation, data curation, writing – original draft. Yizhuo Li: Writing, visualization, testing. Kelly Habib: Data curation, writing, and project administration. Hani S. Mitri: Reviewing, editing, and funding acquisition.Additional informationFundingThis work was financially supported by a research grant from Natural Resources Canada, Clean Growth Program, Grant No. CGP-17-1003, and industry partner Newmont Corporation. The authors are grateful for their support.Notes on contributorsT. ChenTuo Chen holds both Master of Engineering (MEng) and Doctor of Philosophy (PhD) degrees from McGill University. His areas of expertise include the explosive-free rock fracturing method, numerical modeling of mining-induced seismicity, and the design of sill pillars and crown pillars in underground mines.Y. LiYizhuo Li is a PhD candidate in Mining Engineering at McGill University. She is conducting research in McGill’s Mine Design and Numerical Modelling Laboratory while also working as a teaching assistant in the department. Her current research focuses on stress measurement and stability assessment for underground mining.K.-M. HabibKelly Habib completed her PhD in Mining Engineering at McGill University in December 2022. She holds a BSc in Chemistry from University of Ottawa and an MSc in Mining Engineering from McGill University. Her graduate studies mainly revolved around the development of EC for rock breakage in underground mines.H. S. MitriHani S. Mitri is Professor of Mining Engineering at McGill University and founder of McGill’s Mine Design and Numerical Modelling Laboratory. His teaching, research, and consulting activities relate to mine design and rock mechanics with numerical modelling. He is a registered professional engineer in Quebec and a CIM Fellow.