| dc.description.abstract | Loa  Gagak  sub-block  operated  PT  MHU  is  known  to  have  discontinuous  coal  seam which is interpreted to be the results of wash-out. Moreover, mapping the hard and soft material area seems to be  very  challenging. Thus, an ERT survey  has  been conducted using Wenner and Dipole-Dipole configuration with 9 lines each, 235 meters length, and up to 40 meters depth of penetration. The main objective of this study is to delineate the lithology  including  the  coal  seam  based  on  the  resistivity  value  on  every  line  of  the measurements. The results of ERT survey are displayed in resistivity section as a result of inversion on each line with two configurations. The result of Dipole-Dipole configuration is able to image the North-East trend of coal continuity while Wenner configuration could image the upright stratigraphy trend. Though these two configurations confirms coal seam with  NE-SW  trend,  the  results  of  resistivity  imaging  need  to  be  optimized  using  other configuratiosn  in  order  to  able  to  increase  the  accuracy  by  correlating  them  with  other geological data.    Furthermore,  the  ERT  method  has  not  been  able  to  determine  the  boundaries  of  swamp deposits clearly. Another method is needed to identify swamp material so that it can map the thickness and the depth of both soft and the hard material. The SRT method seems to able to image the hardness of the rock based on P-wave velocity based on 3 trial lines.     Keywords: coal, ERT, Wenner, Dipole-Dipole, SRT | en_US |