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 251⁰-290⁰ so unfavorable. It has weight = -10. In siltstone also discontinuity parallel axis of the tunnel. The range located between 241⁰-300⁰. 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.

To prevent landslides, the slope is a crucial component that needs to be evaluated. Mining activities produce slopes, both natural slopes and artificial slopes, and if a slope is not designed properly, its stability will be adversely affected. The purpose of this study is to determine the stability of a slope supported by sedimentary rocks as the constituent material of the slope. Data processing is carried out using the RS2 Version 11 software and finite element methods (FEMs) by considering the value of the strength reduction factor (SRF) and maximum displacement of the slope. The results obtained for stage 1 show that a maximum displacement of 0 m was obtained, along with a critical value of SRF = 1. A maximum displacement of 0.2 m was obtained in stage 2, with a critical SRF of 1.25. In stage 3, 0.2 m was the highest attained displacement, and the critical SRF was 1.26. A maximum displacement of 0.4 m and a critical SRF of 1.31 were found in stage 4. The maximum displacement in stage 5 was 0.8 m, while the critical SRF was 1.34, and the critical SRF in stage 6 was 1.35, while the maximum displacement was 0.8 m. Finally, the maximum displacement in stage 7 was 1.6 m, while the critical SRF was 1.36. A general pattern emerged from the results of stages 1 through 7. Specifically, the maximum permitted displacement value increased with the critical value of SRF. As the slope moved, it also became more stable, with a big critical SRF. If a slope’s deformation exceeds 1.6 m, it will collapse at a safety factor of 1.36. Furthermore, the contour level showed that the factor of safety (FoS) falls between 1.4 and 4.2. Additionally, as sigma 1 and 3 increase, the resulting FoS value increases as well.

Slopes are formed as a result of mining operations. These slopes are classified as artificial slopes. Improper planning of slopes can lead to instability and potentially trigger landslides. PT. Allied Indo Coal Jaya employs the open-pit mining method in its coal mining operations. Slopes are naturally formed in open-pit mines. Additionally, PT. Allied Indo Coal Jaya utilizes blasting for rock demolition. Therefore, it is crucial to assess the impact of blasting activities on slope stability. This study investigates the influence of blasting on slope stability in coal mines using the limit equilibrium method (LEM). The study evaluates the effects of factors such as ground vibration, blast distance, and blast hole count on the factor of safety (FoS) of slopes. The limit equilibrium method (Fellenius, Bishop, Janbu, Spencer, and Morgenstern-Price) is employed to determine the factor of safety. The factor of safety is modeled using RocScience SLIDE version 6.0 in this study. The factor of safety (FoS) is defined as the ratio of the stabilizing force to the destabilizing force acting on the slope. This study also models the influence of ground vibration, distance, and total number of blast holes on the factor-of-safety (FoS) value. The results indicate that the slope remains stable both pre- and post-blasting, with an overall FoS value greater than 1 for the five slopes examined using various limit equilibrium method (LEM) techniques. However, the FoS value decreased prior to blasting due to the impact of ground vibration and blast distance. It is evident that the ground vibration (PPA) increases with the number of blast holes. The amount of ground vibration decreases as the number of blast holes increases. An increased number of blast holes leads to a decrease in the FoS value. The observed decline in slope FoS values and the increase in PPAs is attributable to the growing number of blast holes. The type of explosive, along with its power and rate of detonation, influences the amount of energy produced, which in turn affects the degree of ground vibration. The findings indicate that the slopes remain stable (FoS > 1) both before and after blasting, although blasting slightly reduces the FoS. The study reveals that as the number of blast holes increases, both ground vibration (PPA) and the reduction in FoS increase, underscoring the effects of explosive power and detonation rate on slope stability.

Alternate rock-breaking techniques to drilling and blasting could include using microwaves to break up rock masses. Drilling for blasting has a significant issue with the cost of drill bit replacement in a short time (weekly). The microwave-breaking technology could be a solution, but research is continuing. This research clarifies the proposed methods through a case study of PT. ATC is an andesite quarry that employs the drill-and-blast technique to break rock. This experiment replicates the previous study’s conclusion that rock strength decreases following microwave treatment on two rock strength tests involving the Point Load Index (PLI) and Schmidt Hammer (SH). The dynamic test (PUNDIT) result indicates that the p-wave velocity of microwaved samples is greater than that of non-microwaved samples (NMW). As a consequence of evaporation and mineral transformation within the rock, the density of the rock decreases, and the porosity increases.

Worldwide mining, civil, and environmental engineering projects depend on the safe and sustainable development of slope stability assessments. The study is being conducted at PT. Parambahan Jaya Abadi's mining business license area. 3 slopes are the object of research whose constituent materials are clay and andesite stone. The purpose of this study is to determine the values of Sigma 1, Sigma 3, and FoS slopes which are the basis for determining the stability of a slope. The finite element method (FEM) estimates the factor of safety through an elastic-plastic finite element analysis by progressively decreasing the soil or rock strength variables until failure. From the results, Slope 3 has the greatest values for both cohesion and internal friction angle. The soil's resistance to friction increases with the φ value, indicating a more stable slope. The tensile strength between soil grains and slope stability increases with an increasing value of C. The three slopes are categorized as Good rocks (Rock Class II). The value of sigma 1 is decreasing as seen by the three slopes. The amount of shear stress that needs to be resisted by soil particle cohesion and friction increases with an increasing sigma value of 1. Sigma 3's value is likewise decreasing concerning its upward value. The deviatory stress needed to achieve the limit of plasticity increases with increasing sigma value of 3. The lowest FoS value of the three slopes occurred on slope 1, which was FoS = 3. A FoS value greater than 1.3 indicates that the slope is in a stable state. The Critical SRF value of 4.15 is the same for slopes 1, 2, and 3. Meanwhile, on slopes 1, 2, and 3, the greatest displacement values were 1,499, 1,486, and 1,490. Knowing each maximum displacement amount may help to remind us that if movement occurs beyond that value, a slope is deemed unstable (possible for landslides). Because of this, the company can respond swiftly to prevent landslides on the hillsides. This can be accomplished by putting in place a system of regular slope monitoring and slope strengthening.

Landslide prevention is crucial, particularly for protecting roads and infrastructure in rock landslide-prone areas. This global issue has garnered significant attention from researchers worldwide. This study addresses landslide prevention by modeling the factor of safety (FoS) for slope stability through the Geological Strength Index (GSI), limit equilibrium method (LEM), and finite element method (FEM). A GSI analysis was conducted using RocLab software version 1.0, and slope modeling was performed using RocScience SLIDE version 6.0 and RS2 version 11. The results revealed various cohesion and friction angles across six slopes, with Slope 5 exhibiting the highest FoS values (up to 3.27 with the FEM) and Slope 1 exhibiting the lowest (1.59 with the FEM). All slopes, designed with a uniform geometry, remained stable, exhibiting FoS values greater than 1.1. This study further provides an optimal slope design for the open pit in the andesite mining plan at Anugerah Berkah Sejahtera. These findings highlight the important role of accurate modeling in the assessment of slope stability. With a suggested safe slope height of 10 m and an angle of 80° (FoS = 1.62), slope stability analysis based on the factor of safety (FoS) showed that single slopes made of andesite maintain stability at steep angles. Claystone slopes, however, have a maximum slope height of 30 m at 20° (FoS = 1.27) and 27 m at 50° (FoS = 1.34), requiring more conservative geometries to maintain their stability. For an overall slope that comprises both rock types, a height of 30 m with a slope angle of 60° is recommended (FoS = 1.23) to ensure stability. The critical design condition for a claystone slope occurs at a height of 30 m with a slope angle of 50°, yielding a factor of safety (FoS) of 0.92, which indicates instability (FoS < 1.1). Similarly, a 35 m-high slope with a slope angle of 20° produced an FoS of 1.04, and a 35 m-high slope with a slope angle of 50° produced an FoS of 0.89, further confirming instability. For the overall slope configuration, instability occurs at a height of 30 m with a slope angle of 65° that produces an FoS of 1.09.