Embankments Stability of an Opencast Mine with the Proposal of a New Mining Method For its Reopening (Kef Essennoun, Algeria)

Abstract

The main purpose of our study is to treat the stability problem of the phosphate Kef Essennoun quarry in the mining field of Jebel Onk located in the Northeastern part of Algeria. To achieve these objectives, we started by monitoring the unstable area, using two monitoring systems: control stations and inclinometer. We then carried out a digital assessment of the Northwestern edge stability of the quarry, under the current operating conditions of exploitation. After that, we proposed a new operating plan for the reopening of the depot under the required security conditions. At the end, we carried out an assessment of the edge stability, as the work to reopen and develop the Kef Essennoun quarry progressed. The results show that, under the current operating conditions of exploitation, the Northwestern edge of the Kef Essennoun quarry is unstable (FS<1). The backfilling of the pilot pit of the mine, lead to the assurance of the mine walls stability, by increasing the values of safety factors with a rate of more than 30%. The backfilling of the pilot pit of the mine and the resumption of top-down mining exploitation will ensure the stability of the quarry during and after the operating exploitation mining. The study of the stability of the embankments bleachers, the edges of the quarries and the facings of the slag heaps during the open pit mining of useful ores deposits is an essential step that must be done gradually according to the development of mining works to guarantee the safety of personnel, materials, reserves and the environment.