| Summary: | This research is aimed to determine optimal pit limit that gives economic
value in coal mining. Study area is located at East Barito District, Central
Kalimantan Province within the exploration area of PT. Senamas Energindo
Mineral. The optimal pit limit is determined using Break Even Stripping Ratio
(BESR) analysis.
There are two models of BESR analysis that will be used at this research.
The first model is fixed BESR that has constant variables such as sale of coal per
ton, overburden stripping cost per Bank Cubic Meter (BCM) and coal production
cost per ton as long as mine time. The other is dynamic BESR that has variables
like selling price of coal per ton changing based on econometric forecasting and
overburden stripping cost changing based on changes of dumping distance per
year as long as mining periods.
Research area has a surface of approximately 2.000 hectares. There are
115 points of bore hole at research area. Maximum depth of drilling point is 80
meters with intevals 400 meters.
The coal resources estimating using poligon method indicate a measured
resources of 113.880.060,94 tonnes. As the value of fixed BESR that is obtained
from the analysis is 8,16 BCM/ton which give total coal reserve 60.308.016 ton
with Net Present Value (NPV) USD 21.490.207,90, Internal Rate of Return (IRR)
19% and pay back period 3 year 1 month. Mine age of fixed BESR is 10 years. As
dynamic BESR give total coal reserve 65.297.477 ton with NPV USD
826.886.944,92, IRR 85% and pay back period 1 year 7 month with 11 years of
mine age.
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