INTERNSHIP REPORT — PT BUKIT ASAM
Forty-five report figures move from Pit N terrain and outcrop description through seam-quality plots, core-scale facies and wireline correlation. Interpretations are kept proportional to sample support: the Seam D plot has only two points, Seam A1 only three, and the conflicting Seam B1 values are flagged for reconciliation rather than averaged away.
ALBUM
45 records
The borehole map is the spatial control for every internship correlation that follows. Collar distribution, coordinate reference system, elevation datum and the distinction between mapped seam traces and subsurface picks determine where continuity is observed and where it is interpolated.
The photograph records an active open-pit landscape rather than an untouched natural landform. Excavated slopes, haul access, exposed benches or working surfaces and spoil have modified relief, drainage and exposure, while low residual hills preserve part of the inherited terrain.
Only three plotted observations support the Seam A1 quality panel. Ash and inherent moisture appear to vary inversely with calorific value within that small set, whereas sulfur and volatile matter show no stable visual relation.
The source reports low ash (about 1.30–3.42%) and low sulfur (about 0.18–0.24%) for the plotted Seam A2 samples. That makes A2 the cleanest interval in this limited comparison, but it does not prove a raised-mire origin or a uniform product specification.
The Seam B1 source is internally inconsistent: one summary gives ash of 3.30–4.15%, sulfur of 0.26–0.35% and calorific value of 4,836–4,920, while the later plot/table text gives ash of 2.8–7.0%, sulfur of 0.12–0.20% and calorific value of 4,327–5,030.
Seam B2 combines moderate ash values reaching roughly 6.8% with sulfur around 0.96–1.06% in the source dataset. The restricted sample population can show the observed range, not its mine-wide frequency.
For Seam C, the source gives ash of approximately 3.03–7.29% and sulfur of 0.38–1.39%. The spread is geologically meaningful because it may reflect parting abundance, mineral matter, sulfur mode or sampling support, yet the scatter plot alone cannot choose among those explanations.
Seam D is represented by only two values: total moisture about 24.60–26.78%, ash 4.12–4.90%, sulfur 1.00–1.32% and calorific value 5,171–5,189 in the source table. Two points define a line mathematically but provide no estimate of natural scatter, so correlation coefficients, causal claims and rank comparisons beyond the sampled material would be misleading.
The source places Seam D at about 142–147 m in RTB 09 and 181–185 m in RTS 01; the correlated coal interval is approximately 4 m thick and is described as banded coal, locally with a clay band or parting. In the internship report, the core photograph establishes recovered lithology and vertical order; it cannot measure continuity between boreholes.
Seam C is traced through five boreholes and is described as an 8–14 m banded-coal interval containing a clay parting; the larger control count makes it better constrained laterally than Seams D, B2, B1, A2 or A1. In the internship report, the core photograph establishes recovered lithology and vertical order; it cannot measure continuity between boreholes.
The C–D interburden is represented by very fine- to fine-grained sandstone and siltstone, locally coarser, with flaser, wavy and lenticular bedding. Those heterolithic structures record alternation between traction and suspension fallout, but they do not, on their own, distinguish tidal modulation from other fluctuating-current processes.
The panel correlates Seam B2 at approximately 104–109 m in RTB 11, 107–112 m in RTS 74 and 161–165 m in RTS 06. Across those three wells the source treats it as a roughly 4–5 m banded-coal interval.
The B2–C interburden is dominated by very fine sandstone and siltstone. Its heterolithic character is the principal core observation; environmental assignment requires bed-boundary relationships, sedimentary structures and lateral persistence rather than a log motif alone.
Seam B1 is correlated through RTB 11, RTS 74 and RTS 06 as a comparatively thick, approximately 9–14 m coal body. Clay partings of roughly 0.5–2.5 cm are recorded within the seam and must be carried into any clean-coal thickness or quality calculation.
Between B1 and B2, the source describes pale grey claystone and siltstone with fine heterolithic layering. This interval is a correlation separator as well as a depositional record, so thickness changes must be distinguished from drilling loss, core breakage and marker-pick uncertainty.
This composite panel places Seams A2 and A1 beside the A1–A2 interburden and the partings that interrupt the coal.
The A2 interburden panel records fine heterolithic clastics together with the Suban marker used in the source correlation. The marker is operationally useful because it provides a recognisable level between seam packages, but visual similarity alone does not make it an isochron.
The A2 parting photograph isolates a thin non-coal interval within an otherwise thick, approximately 12–15 m seam envelope. Its thickness, lithology and continuity affect clean-coal thickness, dilution and quality sampling, so it should be logged separately rather than absorbed into an average seam description.
Seam A1 is correlated in RTB 11, RTS 74 and RTS 06 at approximately 29–37 m, 14–24 m and 87–96 m respectively. The source describes a variable 3–10 m seam with clay bands or partings about 2–8 cm thick beneath a mudstone–shale roof.
The A1–A2 interburden is described as fine, locally tuffaceous sandstone with subordinate finer beds. Volcanic input may aid recognition, but a tuffaceous appearance is not automatically an isochron unless petrography or geochemistry demonstrates a correlatable event bed.
The internship panel compares the core-defined D interval across two boreholes with its wireline character. The low-gamma, broadly boxcar-to-cylindrical response is compatible with a laterally recognisable low-clastic interval, while short excursions can be checked directly against the recorded partings.
The internship panel compares the core-defined C interval across five boreholes with its wireline character. The low-gamma, broadly boxcar-to-cylindrical response is compatible with a laterally recognisable low-clastic interval, while short excursions can be checked directly against the recorded partings.
The internship log panel brackets the C–D between core-constrained coal markers. Its serrated or irregular gamma expression is compatible with the alternation described in core—the c–d interburden is represented by very fine- to fine-grained sandstone and siltstone, locally coarser, with flaser, wavy and lenticular bedding.
The internship panel compares the core-defined B2 interval across three boreholes with its wireline character. The low-gamma, broadly boxcar-to-cylindrical response is compatible with a laterally recognisable low-clastic interval, while short excursions can be checked directly against the recorded partings.
The internship log panel brackets the B2–C between core-constrained coal markers. Its serrated or irregular gamma expression is compatible with the alternation described in core—the b2–c interburden is dominated by very fine sandstone and siltstone.
The internship panel compares the core-defined B1 interval across three boreholes with its wireline character. The low-gamma, broadly boxcar-to-cylindrical response is compatible with a laterally recognisable low-clastic interval, while short excursions can be checked directly against the recorded partings.
The internship log panel brackets the B1–B2 between core-constrained coal markers. Its serrated or irregular gamma expression is compatible with the alternation described in core—between b1 and b2, the source describes pale grey claystone and siltstone with fine heterolithic layering.
The internship panel compares the core-defined A2 interval across three boreholes with its wireline character. The low-gamma, broadly boxcar-to-cylindrical response is compatible with a laterally recognisable low-clastic interval, while short excursions can be checked directly against the recorded partings.
The internship log panel brackets the A2–B1 between core-constrained coal markers. Its serrated or irregular gamma expression is compatible with the alternation described in core—the a2–b1 package contains heterolithic fine-grained clastics and the suban marker used in the source correlation.
The internship panel compares the core-defined A1 interval across three boreholes with its wireline character. Here the diagnostic target is the coal-top boundary: the upward change into a finer, generally higher-gamma roof is more important than the shape of the coal trace in isolation.
The internship panel compares the core-defined A1 interval across three boreholes with its wireline character. Here the diagnostic target is the seam body, including short departures from the low-gamma motif that can be tested against the documented internal partings.
The internship log panel brackets the A1–A2 between core-constrained coal markers. Its serrated or irregular gamma expression is compatible with the alternation described in core—the a1–a2 interburden is described as fine, locally tuffaceous sandstone with subordinate finer beds.
These five linked records extend the internship report from topographic and seam-surface control into volumetric cells, geometry validation and resource-domain coding. They remain part of the 127-record software archive and are cross-linked here without being counted twice.
Topographic control for the geological model is documented in MineScape at the 01 · topographic control stage. Topographic control for the geological model is documented in MineScape at the 01 · topographic control stage.
Stacked seam-floor surfaces is documented in MineScape at the 02 · stratigraphic surfaces stage. Stacked seam-floor surfaces is documented in MineScape at the 02 · stratigraphic surfaces stage.
Stratigraphic cell framework is documented in MineScape at the 03 · cell framework stage. Stratigraphic cell framework is documented in MineScape at the 03 · cell framework stage.
Wireframe review of model geometry is documented in MineScape at the 04 · geometry review stage. Wireframe review of model geometry is documented in MineScape at the 04 · geometry review stage.
Spatial-domain coding review is documented in MineScape at the 05 · domain review stage. Spatial-domain coding review is documented in MineScape at the 05 · domain review stage.