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This study made observations on mineralogy, petrological, and petrographic textures related to diagenesis and traces of methane presence in cuttings samples in sedimentary rock in well XS-01, Makassar Strait, Indonesia. The research methods carried out included a description of the cuttings sample, XRD, and petrography aimed at obtaining information on mineralogy, petrology, and diagenesis aspects of rocks, as well as documenting petrographic texture of the presence of methane in samples that prove the presence of methane in the recent past. The results showed that the identified mineralogy are calcite, quartz, amorphous silica, kaolinite, and montmorillonite. The rock types include claystone, siltstone, wackestone, packstone, and crystalline limestone. There are three (3) petrographic textures related to diagenesis: fracturing, calcite cementation, and silicification. Cement is drusy calcite and amorphous silica, representing the diagenesis stage of mesogenesis. The micrite petrographic texture shows as clotted peloidal micrite in wackestone, which was interpreted as a product of microbial activity during carbonate mineral precipitation stimulated by the Anaerobic Oxidation of Methane (AOM) process. This texture indicates the remnant of methane that characterizes the biogenic gas from the chimney gas zone. The gas chimney is common geological structures within the subsurface realm, which is recorded on the seismic sections.very easy to see or easily distinguished from other geologic features on the seismic section. However, the characterization of mineralogy, petrology, and petrographic textures is still rarely found in the literature due to limited accessibility to the interior of gas chimneystill quite rare. In this study, observations were made on mineralogy, petrological, and petrographic textures related to diagenesis and traces of methane gas presence in cuttings samples in sedimentary rock in well XS-01, Makassar Strait, Indonesia. The research methods carried out included a description of the cuttings sample, XRD test, and thin-section petrography aimed at obtaining information on mineralogy, petrology, and diagenesis aspects of rocks, as well as document-ing petrographic textures of traces of the presence of methane gas in samples that prove the presence of methane gas in the recent past. The results showed that the identified mineralogy are calcite, quartz, amorphous silica, kaolinite, and montmorillonite. The rock types include claystone, siltstone, wackestone, packstone, and crystalline limestone. There are three (3) petrographic textures related to diagenesis, namely fracturing, calcite cementation, and silicification. Cements are, with the types of cement including drusy calcite and amorphous silica which represent the diagenesis stage of mesogenesis. The micrite petrographic texture shows as clotted peloidal micrite in wackestone which were interpreted as a product of microbial activity during carbonate mineral precipitation stimulated by the Anaerobic Oxidation of Methane process. This texture is an indicator of remnant of methane that characterizes the biogenic gas from the chimney gas zone. [ABSTRACT FROM AUTHOR]

CV. Bara Mitra Kencana is one of the coal mining company in Sawalunto, Indonesia. The mining activities' pattern of excavation yields natural and artificial slopes. Following observations in BMK-35 mining, it was regularly discovered that there were tiny failures and hanging rocks due to the abundance of rock discontinuity and excessively steep slopes of more than 80°. This study aims to analyze the strength of rocks by testing the Block Punch Index, analyzing the mass class of rocks with the SMR method, and knowing the safety factors using Software Slide Version 6.0. The test results obtained an average compressive strength for Sandstone of 0.3 MPa and 0.4 MPa for siltstone. While the UCS value from BPI is approximately 1.8 MPa for sandstone and 2.2 for siltstone. The acquired UCS measure is in use to determine the rock class. It is observed that the rock condition of the research object is poor category, the type of avalanche occur was the wedge failure. Pit slope safety factor BMK-35 was obtained by of 4.9. [ABSTRACT FROM AUTHOR]

Narogong weir was planned to be located in West Java, Indonesia. The rock types in the weir location are dominated by alternating siltstone and shale marlstone. The tunnel's line was designed to be perpendicular to the axis of an anticline. This study aimed to determine the quality of rock masses at the Narogong diversion tunnel and recommend the tunnel excavation method and support system. The Geological Strength Index (GSI) and Central Research Institute of Electric Power Industry (CRIEPI) classifications were used to determine the rock mass classes and the rock mass qualities. Then, the tunnel excavation method and support systems were resolved by the Rock Mass Rating (RMR) table based on the newly developed GSI-RMR correlation. The laboratory testing shows that siltstone and shale marlstone in the research area had low Uniaxial Compression Strength (UCS) values ranging from 4.5 to 25 MPa and fell into a weak rock class. Although the siltstone and shale marlstone had low UCS values, the drill core evaluations indicated that the alternating layers were classified as fair and good quality rock masses based on GSI and CM – CH class based on CRIEPI. The lower GSI values of the rock masses in BT-09 and BT-12 were affected by the presence of the anticline fold. The tunnel excavation method and support system were divided into two segments based on rock mass qualification. [ABSTRACT FROM AUTHOR]

An experimental study is carried out of the deformation process of the samples of siltstone and limestone with joints under direct shear with constant compressive load. The values of the degree of water saturation and the roughness coefficient of surfaces of joints varied. The aim of the work was to study the character of changes of the parameters of microseismic emission signals depending on the degree of water saturation and the roughness coefficient of the samples under direct shear loading. The first signals of microseismic emission appear at the stresses of 0.3–0.4 of the shear strength for the siltstone samples with high surface roughness values. The number of signals increases at the maximum load value and remains significant until the residual strength section. The highest values of the acceleration amplitude correspond to the break-downing of high roughness peaks. The direct shift occurs during monotonous sliding without sharply pronounced damage for limestone samples that are in a completely water-saturated state. It is confirmed by the absence of significant changes of the characteristics of microseismic emission signals. [ABSTRACT FROM AUTHOR]

RMR (Rock Mass Rating), or also known as the geo mechanics classification has been modified and made as the International Standard in determination of rock mass weighting. Rock Mass Rating Classification has been developed by Bieniawski (since 1973, 1976, and 1989). The goals of this research are investigate the class of rocks base on classification rock mass rating Bieniawski 1989, to investigate the long mass of the establishment rocks, and also to investigate the distance of the opening tunnel without a support especially in underground mine. On the research measuring: strength intact rock material, RQD (Rock Quality Designation), spacing of discontinuities, condition of discontinuities, groundwater, and also adjustment for discontinuity orientations. On testing samples in the laboratory for coal obtained strong press UCS of 30.583 MPa. Based on the classification according to Bieniawski has a weight of 4. As for silt stone obtained strong press of 35.749 MPa, gained weight also by 4.From the results of the measurements obtained for coal RQD value average 97.38%, so it has a weight of 20. While in siltstone RQD value average 90.10% so it has weight 20 also. On the coal the average distance measured in field is 22.6 cm so as to obtain a weight of 10, while for siltstone has an average is 148 cm, so it has weight = 15.Presistence in the field vary, on coal = 57.28 cm, so it has weight is 6 and persistence on siltstone 47 cm then does it weight to 6.Base on table Rock Mass Rating according to Bieniawski 1989, aperture on coal = 0.41 mm. That is located in the range 0.1-1 mm, so it has weight is 4. Besides that, for the siltstone aperture = 21.43 mm. That is located in the range > 5 mm, so the weight = 0.Roughness condition in coal and siltstone classified into rough so it has weight 5. Infilling condition in coal and siltstone classified into none so it has weight 6. Weathering condition in coal and siltstone classified into highly weathered so it has weight 1. Groundwater condition in coal classified into dripping so it has weight 4. and siltstone classified into completely dry so it has weight 15. Discontinuity orientation in coal parallel axis of the tunnel. The range is 251°-290° so unfavorable. It has weight = - 10. In siltstone also discontinuity parallel axis of the tunnel. The range located between 241°- 300°.Base on weighting parameters according to Bieniawski 1989, concluded for rocks are there in class II with value is 62, and able to establishment until 6 months. For the distance of the opening tunnel without a support as far as 8 meters. [ABSTRACT FROM AUTHOR]

The research objective is to describe potential, to analyze the quality and quantity of limestone, and to know the limit distribution of rocks based on the value of resistivity, the pattern of distribution of rocks by drilling, the influence mineral growing on rock against resistivity values, the model deposition of limestone based on the value resistivity of rock and drilling, and the comparison between the interpretation resistivity values based on petrographic studies by drilling. Geologic Formations study area consists of assays consisting of altered sandstone, phyllite, slate, siltstone, grewake, and inset limestone. Local quartz sandstone, schist, genealogy, which is Member of Mersip Stylists Formation, consists of limestone that formed in shallow seas. Stylists Formation consists of slate, shale, siltstone and sandstone. This research methodology is quantitative using experimental observation by survey. This type of research methodology by its nature is descriptive analysis. [ABSTRACT FROM AUTHOR]

The Bee Bluff Structure of South Texas in Zavala County near Uvalde has been found to exhibit unusual features permitting study of impactites and meteorite impact processes from the standpoint of grain-level, nanosecond shock-compression science. The site is characterized by a thin cap of Carrizo Sandstone covering a thin hard Indio fm calcareous siltstone. A soft calcareous silt lies below the hard cap. Calculations based on the Earth Impact Effects web-based program indicate that the site is best described by a 60 m diameter iron meteorite striking the ground at 11 km/sec. Such an impact into sandstone is expected to produce a shock pressure of 250 GPa. A large release wave originates from the bottom of the hard target with upward moving melt-vaporization waves of solid, liquid and vapor products that become trapped at the impact interface. Numerous distinctive types of impactites result from this ‘bottom-up’ release behavior. Evidence for hydrodynamic instabilities and resulting density gradients are abundant at the impact interface. An unusually valuable breccia sample called ‘The Uvalde Crater Rosetta Stone’ contains at least seven types of impactites in a well defined arrangement that can be used to read the billion nanosecond history of the impact and identify scattered impactites relative to their place in that history. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]