TITLE:
Study on Improvement of Dumping Site Stability in Weak Geological Condition by Using Compacted Layer
AUTHORS:
Takashi Sasaoka, Tri Karian, Tsedendorj Amarsaikhan, Akihiro Hamanaka, Hideki Shimada, Kikuo Matsui
KEYWORDS:
Swamp Material, Coal Mining, Out Pit Dump, Waste Rock, Compacted Layer
JOURNAL NAME:
Open Journal of Geology,
Vol.5 No.3,
March
23,
2015
ABSTRACT: Berau Basin, a sub-basin
of Tarakan Basin, had been developed during Eocene to Miocene period. Rocks in
Berau Basin consist of sedimentary, volcanic and igneous rocks aged from
Pre-tertiary until Quaternary epoch. The youngest identified rock formation was
alluvial deposit consists of mud, silt, sand, gravel and swamp with brown to
dark color. This youngest rock formation is relatively weak geological condition
and can cause problems in the coal mining operation. PT Berau Coal as one of
the coal mining companies in Berau Basin area had experienced some problems
related to the occurrence of alluvial deposit. A large failure has occurred at
one of its out pit dumpingarea
which lies over the swamp material. The failure caused a higher operating cost
since it made that the distance for waste rock dumping became to be farther
than the designated area. Therefore, in order to prevent similar failure
occurring at dumping area which lies above swamp material, an improvement of
dumping site stability on weak geological condition has to be needed. The
proposed method for improving the stability of out pit dumping area in weak
geological condition is to construct the compacted layer of waste rock before
the out pit dumping area construction. Based on experimental results, a minimum
of 40 kPa pressure is needed to give a proper compaction to the waste rock. The
result of numerical analysis by Finite Element Method (FEM) shows that
construction of compacted layer on the base of out pit dumping area can improve
its stability.