Pekerjaan eksplorasi batubara yang dilaksanakan pada Triwulan I Tahun anggaran 1976/1977 ini adalah kelanjutan dari pelaksanaan pekerjaan dari tahun anggaran sebelumnya, yaitu eksplorasi batubara di daerah Sapandalam dan Parambahan yang merupakan kuassa pertambangan eksplorasi dari P.N Tambang Batubara Ombilin
the reports mentioned in dr. leithe's expert opinion of may 15, 1956, have also been used for the present report. before the departure of the "wedexro" experts to indonesia a detailed program for the taking of coal samples had been set up.
Indonesia has been known quite a long past for its rich coal deposits. Our company was given a reconnaissance permit in coal Blocks No.I and II in North Kalimantan in February of this year and conducted an on-spot survey in the area.
The geological knowledge of this arean was very limitedbefore mapping by the geological survey of sumatra had started. only one observation had been published in the "topographische end geologischetion of south sumatra)
The BT. balirang forms two semi-circular craterwalls, whereas the sekincau is a younger eruption-point. the sekincau does not possess an actual cone - shape; it is rather an irregular dome, concicting of andesitic material.
This sheet encludes the topographical map-sheets 1:100.000 Nr. 32, 42 and 43 and the top.detail -maps 1:25.000 Nr.43 a, b, g and h. During the geological survey mimerous rivers were measured which had been roughly indicated on the topographical maps; the geological maps were brough up to date according to these measurements.
During May 1973, a geological investigation was carried out in the central part of prangat anticline belonge to prengat ondrangle. The perpose was to looste and to collect data on rock expesure in the central.