PROBABILITY OF FAILURE ANALYSIS OF LOWWALL AND HIGHWALL SLOPE DESIGN OF OPEN PIT COAL MINE PT XYZ IN SOUTH KALIMANTAN
PT XYZ which is a coal open mining company plans to optimize coal reserves at the Mining Business Permit Area (WIUP). This study is conducted to analyze the overall slope stability conditions on the lowwall and highwall slopes based on the PT XYZ Life of Mine (LOM) design and to provide a geotech...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/42119 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | PT XYZ which is a coal open mining company plans to optimize coal reserves at the
Mining Business Permit Area (WIUP). This study is conducted to analyze the overall
slope stability conditions on the lowwall and highwall slopes based on the PT XYZ Life
of Mine (LOM) design and to provide a geotechnically safe overall slope geometry
recommendation as refferen for optimizing the amount of mined reserves in WIUP owned
by PT XYZ.
In accordance with Minister of Energy and Mineral Resources No. 1827K/30/
MEM/2018, slope stability analysis is performed by calculating the safety factor (FK) of
the LOM slope design statically and dynamically, and by calculating probability of
failure (PK). The PK calculation is preceded by determination of distribution function
obtained through the processing of goodness of fit test using Kolmogorov-Smirnov
method and Akaike Information Criterion test for cohesion, friction angle, and density
data of the slope materials. The result of the goodness of fit test processing is selected the
best distribution and produce input parameters in the Monte-Carlo simulation method
using Slide 6.0 software.
Simulation results for the slope of Pit A highwall at pore water pressure factor (hu): 0,6
and 0,8 are stable with probability of failure (PK) of 0% and the value of dynamic safety
factor (FK) are respectively 1,86 and 1,60. The slope of Pit C highwall, that has PK value
of 0%, is stable at hu 0,6 with dynamic FK value of 1,51, but is unstable at hu: 0,8 with
dynamic FK values of 1,23 (below 1,5). The slope of Pit A lowwall at hu: 0,6 and 0,8 are
stable with PK of 0% and the dynamic FK values are respectively, 2,23 and 1,95. The
slope of Pit C lowwall at hu: 0,6 and 0,8 are unstable with PK values ranging between
8,4%-100% and dynamic FK values ranging from 0,45-1,09 (below 1,3).
Based on the results, the slope design recommendations are given by reducing the slope
steepness, reducing the slope height, and changing the geometry of a single slope,
therefore the value of dynamic safety factor (FK) for the slope of Pit C highwall at hu:
0,8 of 1,69 is obtained. While for the slope of Pit C lowwall at hu: 0,6 and 0,8, the PK
value is around 0%-0,3% and the dynamic FK value is between 1,35 - 1,81. |
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