OJSC «Uralmekhanobr», Yekaterinburg, Russia:

M. S. Tankov, Head of Laboratory, tankov_ms@umbr.ru

One of the major objectives in hybrid mining is safe and efficient extraction of ore reserves from pit wall and bottom. This article discusses the successful experience of extracting ore from a pillar in the pit wall at the Molodezhnoe deposit. It was earlier planned to extract the pillar at the late stage of mining using the unsafe method of sublevel caving. Mining safety and planned capacity to be maintained dictated the earlier stage extraction of the ore pillar. Based on the feasibility study, it was decided to extract ore reserves both from the bottom and wall of the pit using the cut-and-fill method with cemented backfill in two stages. The first stage was extraction of mineral reserves from the pit bottom by a single open stope later on backfilled with cemented mixture. At the second stage, before mining, a composite barrier composed of dirt rocks in the capacity of an encasement and a cemented backfill layer was made along the ore-bearing pit wall. Then, under the shelter of the composite barrier, ore reserves in the pit wall were extracted by the open stoping from center to sides. Within an extraction panel, the ore body was divided into stopes oriented across the strike of the ore body. The proposed mining technology allows safe and efficient extraction of ore reserves from pillars at the lowest loss in quantity and quality.

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