ABSTRACT
The mine was located in the city of Opole in southwest Poland. Its owner Odra SA Cement Factory in 2011 celebrated its 100th anniversary. The Odra II Opencast mine covered area of approximately 60 ha and was founded in 1961. Its south part was located closely to the apartment buildings of the city and its east part was situated closely to the Odra River Valley. In the last years the exploitation was conducted mainly in the north-eastern and central part of the pit. The basic parameters of the mining operation are presented below:
– Mining depth: 25.0 m (148 m above the sea level) – Exploitat. level height: lower 18.0 m, higher 7.0 m – Actual angles of slope exploitation levels: 75◦–60◦ – Final slope exploitation angle: 45◦ – General excavation slope angle: 32◦ – Minimum mining level width: 15 m
The mine was operated by two exploitation levels: No.1/153.0-156.0 m and No.2/148.0-150.0 m. In its southern and western part mine was shaped using the explosives and already reached its target range. In these regions the slopes were exposed on the weathering processes from a few to tens of years. As a result of use of the explosives the rocks had numerous cracks, which affected slope stability. The change
into the direct mining techniques resulted in reducing of mining process interference to the structure of rocks. Limestone rock exploitation was conducted by Komatsu hydraulic excavators.They was throwing output rocks directly to the operating level. (Fig. 1-4). As a result of limited operating range of mining excavator the new mining technology necessitates exploitation of several layers approximately of 3 m thick (Fig. 2).
