scholarly journals Analisis Kualitas dan Perkuatan Terowongan Eksplorasi Uranium Eko Remaja Kalan, Kalimantan Barat menggunakan Metode RMR (Rock Mass Rating)

EKSPLORIUM ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 25
Author(s):  
Yuni Faizah ◽  
Wira Cakrabuana ◽  
Dhatu Kamajati ◽  
Putri Rahmawati
Keyword(s):  
Rock Mass ◽  
Uranium Deposit ◽  
Rock Mass Rating ◽  
Geological Structures ◽  
West Kalimantan ◽  
Classification Parameter ◽  
Research Facilities ◽  
Weak Zones ◽  
Actual Rock

ABSTRAK Terowongan Eksplorasi Uranium Eko Remaja Kalan (TEURK) di Kalimantan Barat yang dibangun pada tahun 1980 merupakan salah satu sarana penelitian cebakan uranium di Indonesia. Terowongan ini menembus Bukit Eko Remaja sepanjang 618 m, mulai dari pintu Remaja hingga TRK-7. Mineralisasi uranium di lokasi ini dikontrol oleh urat-urat tak beraturan (stockwork) yang sangat rapat pada batuan metalanau dan metapelit. Tingginya kerapatan struktur geologi tersebut membentuk beberapa zona lemah di dalam terowongan. Zona lemah tersebut berpotensi menyebabkan terjadinya longsor batu dan tanah. Penyangga sementara terbuat dari tiang-tiang kayu dipasang di zona tersebut untuk perkuatan terowongan. Saat ini tiang kayu tersebut tidak lagi mampu menyangga terowongan sehingga sering terjadi longsor batu dan tanah di dalam terowongan. Penelitian ini bertujuan untuk mengetahui kualitas massa batuan aktual dan menentukan jenis perkuatan yang sesuai agar terowongan tetap aman. Survei palu Schmidt dan scanline pada zona tak berpenyangga (kedalaman 50–297 m dan 355–538 m) dilakukan untuk mengambil data parameter klasifikasi Rock Mass Rating (RMR). Hasil pengukuran menunjukkan bahwa massa batuan TEURK di kedalaman tersebut memiliki nilai RMR 52-71 (sedang–baik). Perkuatan yang direkomendasikan adalah pemasangan baut batu dan beton semprot konvensional.ABSTRACT Tunnel for Exploration of Uranium Eko Remaja Kalan (TEURK) in West Kalimantan, built-in 1980, is one of the uranium deposit research facilities in Indonesia. The tunnel penetrated Eko Remaja Hill along 618 m, from Remaja to TRK-7 access. Uranium mineralization in this area controlled by dense stockwork veins on metasilt and metasandstone rocks. The high-dense geological structures create some weak zones in the tunnel. These zones are potentially causing rocks and soil slides. Temporary supports made of wood-piles were installed in these zones to support the tunnel. Currently, these piles are not capable at the tunnel, so that rocks and soil slides occurred inside the tunnel. The research aimed to determine the quality of actual rock mass and determine the appropriate type of reinforcement to keep the tunnel safe. Schmidt hammer and scanline surveys on the unsupported zone (50–297 m and 355–538 m depth) carried out to collect the classification parameter data of Rock Mass Rating (RMR). The measurement result shows that the rock mass of TEURK on the depth has an RMR value of 52–71 (fair-good). Reinforcement recommendations for the tunnel are rock bolts and conventional shotcretes installation.

scholarly journals Evaluasi Massa Batuan Terowongan Eksplorasi Uranium Eko-Remaja, Kalan, Kalimantan Barat

EKSPLORIUM ◽  
2016 ◽  
Vol 37 (2) ◽  
pp. 89
Author(s):  
Dhatu Kamajati ◽  
Heri Syaeful ◽  
Mirna Berliana Garwan
Keyword(s):  
Rock Mass ◽  
Uranium Deposit ◽  
Rock Mass Rating ◽  
Rock Support ◽  
Safety Level ◽  
West Kalimantan ◽  
Rock Mass Characterization ◽  
Ground Support ◽  
Uranium Exploration ◽  
Weak Zones

ABSTRAKTerowongan eksplorasi uranium Eko Remaja, Kalan, Kalimantan Barat merupakan salah satu sarana penelitian cebakan uranium yang sangat penting. Terowongan ini dibangun tahun 1980 dengan panjang 618 meter dan menembus Bukit Eko di kedua sisinya. Batuan di terowongan ini relatif kompak, tetapi memiliki zona lemah di beberapa bagiannya. Penyanggaan merupakan metode yang digunakan untuk menanggulangi keruntuhan tanah dan batuan yang terjadi pada zona lemah di terowongan. Pemasangan penyangga yang selama ini dilakukan berdasarkan pola keruntuhan yang terjadi pada saat pembukaan terowongan tanpa melalui studi khusus menyangkut karakterisasi massa batuan dan kebutuhan sistem penyangga. Penelitian ini dilakukan untuk mengevaluasi tingkat keselamatan terowongan Eko-Remaja dan kesesuaian lokasi penyangga. Evaluasi dilakukan dengan membandingkan karakteristik massa batuan menggunakan metode Rock Mass Rating (RMR) antara lokasi penyangga batuan terpasang dan lokasi penyangga batuan tidak terpasang. Berdasarkan hasil analisis, nilai RMR pada lokasi terpasang penyangga diklasifikasikan ke dalam kelas IV atau batuan buruk. Sementara itu, di lokasi tidak terpasang penyangga batuan diklasifikasikan ke dalam kelas II atau batuan baik. Berdasarkan korelasi antara hasil perhitungan RMR dengan roof span terowongan Eko-Remaja disimpulkan bahwa posisi penyanggaan terowongan yang diwakili oleh lokasi pengamatan pada kedalaman 38 m, 73 m, dan 165 m sudah sesuai dengan sistem karakterisasi massa batuan menggunakan metode RMR. ABSTRACTEko-Remaja uranium exploration tunnel, Kalan, West Kalimantan is one of the important facilities for uranium deposit research. The tunnel was built in 1980 with a length of 618 meters penetrating Eko Hill on both sides. The rock inside the tunnel is relatively compact, but it has weak zones in some area. Ground supporting is a method used to overcome the soil and rock collapses which occurred in the tunnel weak zones. Installation of ground supporting system throughout the recent time based on the soil collapse pattern, which occurred when the tunnel opened without any specific study related to rock mass characterization and the requirement of ground support system. This research conducted to evaluate the safety level of Eko-Remaja tunnel and the suitability of ground support location. The evaluation performed by comparing the rock mass characteristics using Rock Mass Rating (RMR) method between the installed rock support and uninstalled rock support locations. Based on the analysis result, RMR value on the installed ground support is classified as class IV or poor rock. Meanwhile, on uninstalled location, the rock is classified as class II or fair rock. Based on the correlation between RMR calculation result and Eko-Remaja tunnel roof span, it is concluded that tunnel ground supports position which are represented by observation location on 38 m, 73 m, and 165 m depth are suitable with rock mass characterization system using RMR method.

scholarly journals Quantifying influence of drilling additional boreholes on quality of geological model

2019 ◽  
Vol 56 (3) ◽  
pp. 347-363 ◽  
Author(s):  
Marie-Hélène Fillion ◽  
John Hadjigeorgiou
Keyword(s):  
Rock Mass ◽  
Drill Hole ◽  
Open Pit ◽  
Hole Density ◽  
Geological Model ◽  
Mine Sites ◽  
Definition Of ◽  
Actual Rock ◽  
Geotechnical Model

Geotechnical stability analysis in open-pit mines requires access to a representative geotechnical model. The confidence level in the collected geotechnical data influences slope design. This paper investigates the influence of the number of boreholes, drilled to collect geological information, on the quality of one component of the geotechnical model, the geological model. The number of boreholes influences the number of rock core samples collected for the identification of rock type, and the definition of geotechnical domains and their boundaries within the rock mass. A challenge in the definition of the geotechnical domains is the determination of the drill hole density that minimizes the variation in the interpreted geological model from the actual rock mass. To quantify the influence of the drill hole density, boreholes are simulated in the most recently updated geological model for three mine sites. The simulated drill hole density is increased progressively until the variation of the interpreted section, compared with the original section, is minimized. A classification strategy was developed to determine the complexity level for each geotechnical domain. Furthermore, a series of empirical quantitative guidelines are presented prescribing the minimum drill hole density per domain complexity, while limiting variations from the actual rock mass.

scholarly journals Analysis of Rock Mass Rating Classification with Using RMR Method

2021 ◽  
Vol 6 (1) ◽  
pp. 133-136
Author(s):  
Sukardan Tawil ◽  
Muh. Imran Syam ◽  
Irianto Uno
Keyword(s):  
Rock Mass ◽  
Slope Angle ◽  
Friction Angle ◽  
The Other ◽  
Rock Mass Rating ◽  
The Road ◽  
A Value ◽  
On The Road ◽  
Central Sulawesi

The looseness that occurs on the road along Tawaeli-Toboli is a very important issue to be examined because the road is the most important axis road in Central Sulawesi - Indonesia. The goal to be achieved is to know the value of the quality of the rocks and their relation to the size of the slope angle on the road, especially at km 16 to km 26 from Palu City, using the Rock Mass Rating (RMR) method. From the analysis of RMR obtained one slope whose description of rocks is poor, namely on slope 3 with a value of RMR of 28 and a medium description with a value of 51 is on slope 1, for the other six slopes the description of the rock is still a good rock state with values ranging from 63-73. It is concluded that the lowest RMR value requires special attention to be on slope 3. Thus, the friction angle in small rocks, the value of RMR is also small, and the type of soil indicated is bad.

scholarly journals ROCK MASS RATING OF CAVITY LIMESTONE LAYER IN REMBANG, CENTRAL JAVA, INDONESIA

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
R. Andy Erwin Wijaya ◽  
Dwikorita Karnawati ◽  
Srijono Srijono ◽  
Wahyu Wilopo
Keyword(s):  
Rock Mass ◽  
Solution Process ◽  
Research Area ◽  
Rock Mass Rating ◽  
Mine Design ◽  
Weak Zone ◽  
Rock Mass Characterization ◽  
Central Java ◽  
Geological Conditions

mine design. Mine design is determined by the rock mass quality, which varies from one mine location to another, depending on the geological conditions. The research area is located in limestone quarry of Sale District, Rembang Regency, Central Java Province, Indonesia. In the study area, a cavity zone is exposed at the wall of quarry bench and occurs by a solution process. The cavity layer zone is a weak zone which has caused bench failures. The objective of this research is to evaluate the quality of the cavity limestone layer for a safe mine design using Rock Mass Rating (RMR) system. Final result of the research is a rock mass characterization, specifically for the cavity limestone layer. Keywords: Rock mass rating, limestone, cavity layer

scholarly journals Finite-difference based response surface methodology to optimize tailgate support systems in longwall coal mining

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Satar Mahdevari ◽  
Mohammad Hayati
Keyword(s):  
Compressive Strength ◽  
Response Surface Methodology ◽  
Rock Mass ◽  
Finite Difference ◽  
Longwall Mining ◽  
Support Systems ◽  
Rock Mass Rating ◽  
Slake Durability Index ◽  
Proposed Model ◽  
Durability Index

AbstractDesigning a suitable support system is of great importance in longwall mining to ensure the safe and stable working conditions over the entire life of the mine. In high-speed mechanized longwall mining, the most vulnerable zones to failure are roof strata in the vicinity of the tailgate roadway and T-junctions. Severe roof displacements are occurred in the tailgate roadway due to the high-stress concentrations around the exposed roof span. In this respect, Response Surface Methodology (RSM) was utilized to optimize tailgate support systems in the Tabas longwall coal mine, northeast of Iran. The nine geomechanical parameters were obtained through the field and laboratory studies including density, uniaxial compressive strength, angle of internal friction, cohesion, shear strength, tensile strength, Young’s modulus, slake durability index, and rock mass rating. A design of experiment was developed through considering a Central Composite Design (CCD) on the independent variables. The 149 experiments are resulted based on the output of CCD, and were introduced to a software package of finite difference numerical method to calculate the maximum roof displacements (dmax) in each experiment as the response of design. Therefore, the geomechanical variables are merged and consolidated into a modified quadratic equation for prediction of the dmax. The proposed model was executed in four approaches of linear, two-factor interaction, quadratic, and cubic. The best squared correlation coefficient was obtained as 0.96. The prediction capability of the model was examined by testing on some unseen real data that were monitored at the mine. The proposed model appears to give a high goodness of fit with the accuracy of 0.90. These results indicate the accuracy and reliability of the developed model, which may be considered as a reliable tool for optimizing or redesigning the support systems in longwall tailgates. Analysis of variance (ANOVA) was performed to identify the key variables affecting the dmax, and to recognize their pairwise interaction effects. The key parameters influencing the dmax are respectively found to be slake durability index, Young’s modulus, uniaxial compressive strength, and rock mass rating.

scholarly journals Influence of the groundwater level on the bearing capacity of shallow foundations on the rock mass

2021 ◽  
Author(s):  
Ana Alencar ◽  
Rubén Galindo ◽  
Svetlana Melentijevic
Keyword(s):  
Rock Mass ◽  
Bearing Capacity ◽  
Groundwater Level ◽  
Sensitivity Study ◽  
Shallow Foundations ◽  
Unit Weight ◽  
Geological Strength Index ◽  
Strength Index ◽  
Mass Type

AbstractThe presence of the groundwater level (GWL) at the rock mass may significantly affect the mechanical behavior, and consequently the bearing capacity. The water particularly modifies two aspects that influence the bearing capacity: the submerged unit weight and the overall geotechnical quality of the rock mass, because water circulation tends to clean and open the joints. This paper is a study of the influence groundwater level has on the ultimate bearing capacity of shallow foundations on the rock mass. The calculations were developed using the finite difference method. The numerical results included three possible locations of groundwater level: at the foundation level, at a depth equal to a quarter of the footing width from the foundation level, and inexistent location. The analysis was based on a sensitivity study with four parameters: foundation width, rock mass type (mi), uniaxial compressive strength, and geological strength index. Included in the analysis was the influence of the self-weight of the material on the bearing capacity and the critical depth where the GWL no longer affected the bearing capacity. Finally, a simple approximation of the solution estimated in this study is suggested for practical purposes.

scholarly journals Weightage Effect during Back-Calculation of Rock-Mass Quality from the Installed Tunnel Support in Rock-Mass Rating and Tunneling Quality Index System

2019 ◽  
Vol 9 (10) ◽  
pp. 2065 ◽  
Author(s):  
Jonguk Kim ◽  
Hafeezur Rehman ◽  
Wahid Ali ◽  
Abdul Muntaqim Naji ◽  
Hankyu Yoo
Keyword(s):  
Rock Mass ◽  
Quality Index ◽  
Rock Bolt ◽  
Rock Mass Rating ◽  
Rock Mass Quality ◽  
Back Calculation ◽  
The Difference ◽  
Bolt Spacing ◽  
Q System ◽  
Selection Of

In extensively used empirical rock-mass classification systems, the rock-mass rating (RMR) and tunneling quality index (Q) system, rock-mass quality, and tunnel span are used for the selection of rock bolt length and spacing and shotcrete thickness. In both systems, the rock bolt spacing and shotcrete thickness selection are based on the same principle, which is used for the back-calculation of the rock-mass quality. For back-calculation, there is no criterion for the selection of rock-bolt-spacing-based rock-mass quality weightage and shotcrete thickness along with tunnel-span-based rock-mass quality weightage. To determine this weightage effect during the back-calculation, five weightage cases are selected, explained through example, and applied using published data. In the RMR system, the weightage effect is expressed in terms of the difference between the calculated and back-calculated rock-mass quality in the two versions of RMR. In the Q system, the weightage effect is presented in plots of stress reduction factor versus relative block size. The results show that the weightage effect during back-calculation not only depends on the difference in rock-bolt-spacing-based rock-mass quality and shotcrete along with tunnel-span-based rock-mass quality, but also on their corresponding values.

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