Development of high power microwave applicator for rock preconditioning

在硬岩矿山，连续采矿法仍然面临着许多挑战，效率还很低。从2008年开始，我们的团队探索了使用爆炸自由破岩技术进行连续采矿的各种可能方法。结果表明，连续开挖最可行的技术是采用微波辐射与机械切割工具相结合的方法对岩石进行预处理。这一结论引起了矿业公司的注意，并导致在2011-2016年(第二阶段)获得了NSERC CRD赠款。论证了影响岩石样品辐照的基本参数及其对岩石强度降低的影响。本研究对微波辅助破岩技术在开挖中应用的可行性进行了研究和论证。此外，之前的NSERC CRD赠款使申请者能够建造最先进的15千瓦微波辅助岩石破碎试验台，这是加拿大麦吉尔大学独有的，也是世界上为数不多的试验台之一。2017-2022年，我们的岩石微波研究进入了第三阶段。NSERC发现资助(DG)、三家公司支持的CRD资助以及NSERC RTI成功开展了研究。第三阶段的目标是大规模验证微波辅助岩石预适应的概念。通过NSERC RTI在第三阶段要求的设备是一个100千瓦的岩石微波系统，以升级我们的旧的15千瓦岩石微波系统，以便能够在高功率微波辐射下进行大规模的概念验证测试。我们第三阶段最重要的成果是深入了解和开发了一种具有成本效益和能量效率的微波辐射在大规模试验中用于岩石弱化的秘密配方；即在高能量密度和非常短的时间内，电磁波爆炸被有效地用于打破晶界中的矿物内部键，导致相对于已公布的数据的微波能量(WOME)的衰减程度高出数量级。目前，我们的岩石微波项目正进入第四阶段，并准备在采掘工作面进行原型和中试测试。由行业合作伙伴支持的NSERC发现赠款(DG)、MITACS Accelerate和NSERC联盟赠款正在进行中。第四阶段的目标是开发一种新型的硬岩微波辅助掘进机原型。因此，NSERC RTI赠款中要求的设备是开发一种独特的用于岩石预处理的高功率微波辐射器，将其集成到我们现有的100 kW微波发生器中。这一独特的高功率喷头将使我们能够开发出第一个用于采煤工作面微波辅助岩石预处理试验的样机。该设备对1名RA、1名PDF、8名博士、1名硕士和几名本科生暑期实习学生的HQP培训也至关重要。这将为学生首次开发和进行机器的现场试验提供经验。

In hardrock mines, continuous mining method still faces many challenges and far from efficient. Started in 2008, our team had explored various possible method of continuous mining using explosive free rock breaking techniques. It was concluded that the most feasible technique for continuous excavation is to precondition the rock using microwave irradiation coupled with mechanical rock cutting tool. This conclusion drew the attention of mining companies and resulted in securing an NSERC CRD grant in 2011 - 2016 (Phase II). Basic parameters affecting the irradiation of rocks samples and its influence on the reduction of rock strength has been demonstrated. This study investigated and proved the feasibility of using microwave-assisted rock breaking technology in excavation. Also, this previous NSERC CRD grant enabled the applicants to build a state-of-the-art 15 kW microwave-assisted rock breakage test rig, unique to McGill University in Canada and one of the few in the world. In 2017 - 2022, our rock-microwave research entered Phase III. NSERC Discovery Grant (DG), CRD grant supported by three companies, along with NSERC RTI were successfully carried out. The objective of Phase III was large-scale proof of concept of microwave-assisted rock preconditioning. The equipment requested through NSERC RTI in Phase III was a 100 kW rock-microwave system to upgrade our old 15 kW rock-microwave system in order to be able to carry out large-scale tests for proof of concept under high-power microwave irradiation. The most significant outcome from our Phase III was an in-depth understanding and development of a secret recipe for a cost-effective and energy-efficient microwave irradiation for rock weakening in large-scale tests; that is, at high energy density and a very short period of time, such that the electromagnetic wave burst is effectively used to break intra-minerals bonds in grain boundaries, resulting to order-of-magnitude higher weakening over microwave energy (WOME) as compared to published data. Currently, our rock microwave project is entering Phase IV and is ready for prototyping and pilot testing in the mining face. NSERC Discovery Grant (DG), MITACS Accelerate and NSERC Alliance grants, supported by industry partners are underway. The objective of Phase IV is to develop a novel prototype of a microwave-assisted excavation machine for hardrock. Therefore, the equipment requested in this NSERC RTI grant is to develop a unique high-power microwave applicator for rock preconditioning to be integrated into our existing 100 kW microwave generator. This unique high-power applicator will enable us to develop the first prototype for microwave-assisted rock preconditioning testing in the mining face. The equipment is also vital for the HQP training of 1 RA, 1 PDF, 8 PhDs, 1 MSc and several undergraduate summer internship students. This will provide students with experience to develop and conduct in-field trial of the machine for the first time.