Author 1:
Name & Surname: Petrov A. N.
Company: North Eastern Federal University (Yakutsk, Russia)
Work Position: Head of department
Scientific Degree: Assistant Professor, Candidate of Engineering Sciences

Author 2:
Name & Surname: Petrov D. N.
Company: Institute of Mining of the North, Siberian Branch, Russian Academy of Sciences (Yakutsk, Russia)
Work Position: Researcher
Contacts: e-mail: petrovdn74@mail.ru

The article describes the developments of the Institute of Mining of the North, SB RAS, represented by a new design of room-and-pillar mining with ice-rock backfill in permafrost zone and a technology of ore extraction by slightly inclined rooms (entry ways) and their layer-by-layer filling with rocks that are then watered and frozen under cold airflow (in winter). The mining and backfilling technology is based on using modern self-propelled drilling machines and load–haul–dumpers, and, as against the traditional scraper transportation of broken ore and backfill mixture, ensures lower labor content and higher safety of mining operations. Rooms are divided into first and second stage extraction: first, extraction, backfilling and freezing is performed in rooms that are entry ways (first stage) and then in rooms that are pillars between the entry ways. Ore cutting in inclined rooms is carried out bottom-up, and ice–rock backfill is placed top-down (down grade), by layers 50 cm thick. Ore is extracted with blasting, shotholes are drilled by self-propelled drill rigs, broken ore and rocks are hauled off by self-propelled load–haul–dumpers. The ice-rock backfill is recommended to be made of barren rocks broken in rock drifts, as well as of sand, sand-and-gravel mixture, mill tailings and boilerhouse waste with fragments not larger than 20 cm. The necessary conditions for the ice-rock backfill technique implementation are air accumulation in mine workings in cold season and use of various heat-insulation methods in warm season. Backfilling should be started when ground surface temperature reaches stable negative level below –15 °С.

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