MineSched software. It was determined that implementing six-monthly backfilling results in the removal of a significant degree of flexibility from the mining sequence, thereby extending the total mining period by a period of four years. Figure 5 – Bürgl open pit and historical waste dump (inside blue area). The red cone represents the future backfill storage in the former open pit. Consequently, it is imperative to ensure the availability of sufficient backfill material during the winter months as well. Therefore, it is proposed to follow a strategy where backfill material is stored in the historical open-pit, with subsequent extraction of the material via an underground drawing and backfill collecting system. Figure 5 illustrates the dumped backfill cone within the open-pit mine. The historical waste dump is marked by the blue line. 5. CONCLUSIONS AND OUTLOOK The study demonstrates the technical feasibility of underground magnesite extraction at Bürgl using sublevel stoping with rockfill, selected for safety, selectivity, and cost-effectiveness in a complex alpine setting. Design parameters were derived from empirical and numerical methods, incorporating stope geometries, local stope pillars, and barrier pillars to manage shear along the porphyroid zone, alongside a strict mining-andbackfill sequence and integration of existing infrastructure. A key operational risk is seasonal backfill availability; the proposed winter storage in the former open pit with underground draw mitigates sequence disruptions and supports year-round stability. Next steps include refining geotechnical characterization of weak units, deploying instrumentation for pillar and stope monitoring. Moreover, the feasibility of an underground draw of backfill has to evaluated using DEM-simulations. Besides that, the design of appropriate ventilation has to done.
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