Compressive strength is one of the mechanical properties of rock behavior. This study focuses on the Balikpapan and Kampungbaru Formations located in the Kutai Kartanegara area, East Kalimantan. The Schmidt Hammer testing method was applied due to the lack of previous studies utilizing this tool to evaluate rock hardness in correlation with compressive strength. The research site is situated in the Kutai Kartanegara area, specifically in the districts of Muara Badak, Muara Jawa, and Sanga-Sanga. Field observations revealed the presence of claystone slopes at predetermined locations. Based on the test results, the uniaxial compressive strength (UCS) values for the Balikpapan Formation range from 3.453 MPa to 5.454 MPa, while the Kampungbaru Formation ranges from 3.317 MPa to 8.571 MPa. The Schmidt Hammer rebound number (RN) values for the Balikpapan Formation range from 17 to 19.6, and for the Kampungbaru Formation from 15 to 23.7. A negative correlation was found between the rebound number and UCS, where higher RN values tend to correspond with lower UCS values. This is supported by the linear regression analysis showing a negative coefficient (-0.450).
 

In the Kutai Basin area, seasonal changes such as high rainfall can significantly increase groundwater content, so that the effect of water content on the shear strength of claystone, increasing water content in rocks tends to decrease shear strength. Water in the pores or fractures can increase pore water pressure and reduce effective normal stress. Shear strength is one of the most important mechanical parameters used to assess soil and rock stability, this parameter is very important in slope stability analysis, foundation planning, and various civil engineering and mining applications. Therefore, this study was conducted to determine whether the water content in rocks can affect the strength of rocks in receiving shear forces. The method used in this study is more quantitative and specific to the effect of water content on the shear strength of claystone in this area. Increasing water content in rocks tends to reduce shear strength. This study was conducted by taking claystone samples from several locations in the Kutai Basin. Data collection in the form of primary data and secondary data for testing physical properties and testing mechanical properties, in testing physical properties, the water content value will be taken as supporting data which is one of the factors that affect rock strength, in testing mechanical properties, claystone shear strength data will be taken. From the results of the physical properties test calculations, the air content in each Formation is obtained, namely, in the Kampungbaru Formation the minimum air content value is 15.54% and the maximum is 20.17%, in the Balikpapan Formation the minimum air content value is 10.21% and the maximum is 12,88%, in the Palaubalang Formation the minimum air content value is 10.49% and the maximum is 22.87%. The results of the strength of the claystone in receiving shear forces in the Kutai Basin are the Muara Jawa location 0.486MPa, Tanah Datar location 0.500 MPa, Sanga-sanga location 0.333 MPa, Muara Badak location 0.269, Air Putih location 0.711MPa, Mugirejo location 0.021 MPa and Lempake location 0.092 MPa.

Durability is defined as a measure of a rock's resistance to weathering and disintegration when the rock undergoes weathering processes over a short period of time. The susceptibility of rocks to disintegration is related to their low durability. Rock durability is often measured using the slake durability test. The slake durability test is widely used to assess physical changes resulting from wetting-drying processes (Franklin and Chandra, 1972). Therefore, slake durability testing is conducted to understand the weathering of rocks caused by heat and water, particularly clay stones which are one of the constituent rocks on a slope. The sampling location is around Sanga-sanga and Muara Badak. Sampling was conducted with coordinate points and the Balikpapan and Kampungbaru formations. The claystone samples taken were then brought to the Mineral and Coal Technology Laboratory of the Engineering Faculty of Mulawarman University for Slake Durability tests. In this study, the lowest index value obtained was 45.7% and the highest value was 93%, indicating high to very high durability. The difference in the durability index values of claystone at the research locations indicates the presence of variables that can affect the slake durability index values of the claystone in the Balikpapan and Kampungbaru formations, including grain size and mineral content as well as geological conditions at the research site. Based on the results of the claystone durability tests, the durability index value (Id2) was obtained, indicating that the sandstone at the research location falls into the classification of high to low.

This study aims to evaluate the performance of the loading and unloading equipment in coal mining activities at the Mahakam Pit, PT Insani Bara Perkasa Site Km 11, East Kalimantan. The research was motivated by the importance of achieving mechanical equipment performance standards according to the Decree of the Minister of Energy and Mineral Resources No. 1827 of 2018. Data were obtained through direct observation and analysis of actual working time and evaluation of operational constraint factors. The results of the analysis showed that before the evaluation, the mechanical availability (MA) value was 87.24%, physical availability (PA) 88.51%, availability utilization (UA) 88.73%, and effective utilization (EU) 78.54%. After evaluating the constraint time, there was an increase in all parameters: MA to 88.71%, PA to 89%, UA increased to 90%, and EU reached 80%. This evaluation also had an impact on increasing the productivity of the loading and unloading equipment from 268.41 bcm/hour to 284.43 bcm/hour. Thus, the evaluation of work obstacles is proven to be effective in increasing the efficiency and productivity of the digging-loading equipment at the research location.

Disposal area is an area at an open pit mine that is used as a place to store or dispose of worthless materials. Disposal must also follow the specified safety factor standards, if the disposal design is not safe after being analyzed by a geotechnical engineer, the design must be redesigned to achieve the desired safety factor value. One way to increase the fk value is to make a Counterweight plan in making disposal. Where Counterweight is a fill material that is made with special treatment so that the soil bearing capacity increases which functions to withstand the load on it. Landslides on disposal slopes are one of the serious problems faced in mining activities, especially in areas with vulnerable geological and topographic conditions. PT Jembayan Muarabara, which operates in Marangkayu District, Kutai Kartanegara Regency, East Kalimantan Province, is no exception to this challenge. The A–A’ cross section shows a safety factor value of 1.118 in saturated conditions, which indicates that the slope is at a stable limit and needs to be improved through engineering such as adding counterweights. The B–B’ cross-section has a safety factor value of 2.332, which is included in the safe category and has met the provisions of the ESDM Ministerial Decree No. 1827 K/30/MEM/2018. The C-C’ cross-section has a safety factor value of 1.511, which is included in the safe category and has met the provisions of the ESDM Ministerial Decree No. 1827 K/30/MEM/2018.

The mining system applied by PT Bukit Baiduri Energi is an open pit mining system utilizing the open-pit method. The application of the open-pit method creates a depression that has a high potential to become a catchment area for both surface runoff and groundwater. In the mining pit of PT Bukit Baiduri Energi, there is a sump located at an elevation of -86 meters above sea level (mdpl). The planned mining boundary is at an elevation of -110 mdpl. Therefore, this research aims to determine the area of the catchment, runoff discharge values, sump capacity, and pump capacity, so that the volume of incoming water can be known, allowing for the control of the sump to prevent overflow that could disrupt mining activities.. Based on the data obtained and the calculations performed, the catchment area was found to be 103.42 ha. In the calculation of runoff discharge using the rational method, the total runoff discharge entering sump A9 was found to be 4,211.66 m3/day. The capacity of the sump was measured at 125,187.62 m3. In the pump capacity calculation, the pump capacity based on the pumping discharge was found to be 2,926.80 m3/day.

Stockpiles are accumulations of materials such as coal or ore stored at specific locations. Accurate stockpile volume measurement is crucial in the mining and logistics industries for inventory management and cost efficiency. Conventional methods like Real-Time Kinematic (RTK) GPS rely on surface coordinate measurements but require numerous points, especially for irregular-shaped objects. Newer technologies like Terrestrial Laser Scanners (TLS) offer high-precision alternatives by capturing thousands of points per second, expediting and enhancing the resolution of volume measurements. This study compares TLS and RTK GPS methods in measuring the volume of andesite rock stockpiles at PT Bara Tabang. This research uses a quantitative approach, involving six Ground Control Points (GCPs) measured using the Sokkia GRX2 RTK GPS on October 24, 2024. TLS generated over 8.6 million point cloud data filtered down to 35,197 points, while RTK GPS yielded 2,276 coordinates. Accuracy testing showed very small RMSE values (RMSEr: 0.008 m; RMSEz: 0.007 m), and both LE90 and CE90 demonstrated 90% confidence within a 0.012 m range. Volume calculation using Surpac software with the cut and fill method showed TLS produced a volume of 18,766 bcm (51,982 tons/m³), while RTK GPS resulted in 18,694 bcm (51,782 tons/m³), with a difference of 72 bcm or 0.211%.These results indicate that both methods offer acceptable accuracy; however, TLS provides greater data density, efficiency, and precision, particularly for complex or large-scale stockpile objects. Therefore, TLS is recommended for high-accuracy volume measurement in mining operations that require efficiency and detailed analysis.

Mining roads play an important role in supporting the smooth running of mining activities, especially in the process of transporting materials. The bearing capacity of the soil as a road subgrade greatly affects the stability and resistance of the road to heavy equipment loads. This study aims to analyze the effect of the plasticity index and compaction parameters on the California Bearing Ratio (CBR) value, as well as to determine the thickness of the road layer based on the laboratory CBR value. Testing was carried out at the South Pit of PT. Bina Sarana Sukses site PT. Baramulti Suksessarana with a field test method using the Dynamic Cone Penetrometer (DCP) and laboratory tests such as proctor tests, Atterberg limit tests, and CBR tests on various variations of clay and sand soil mixtures. The results showed that increasing the plasticity index decreased the CBR value, while increasing the maximum dry density and decreasing the optimum water content increased the CBR value. Based on the laboratory CBR value, recommendations were obtained for the appropriate road layer thickness to ensure optimal bearing capacity for heavy equipment passing through the research area.

In rehandling activities In coal processing activities, mechanical tools such as crushers are needed to obtain production results in accordance with the company's desired targets according to the crusher target, therefore in processing it is necessary to carry out precise calculations, so that the ability of the tool (crusher) and know what things greatly affect the production processing process, so that it can be used optimally and has a high efficiency value for optimal production. Therefore, it is necessary to evaluate the results of the crusher production and the productivity of the support unit during rehandling activities in achieving the production target at ROM Port Area 2 in order to adjust the ability of the tool and other influencing factors with the crusher production target desired by the company. Actual rehandling productivity meets the crusher production plan target of 1100tph. Productivity in each zone with DT wheel 10, namely zone H there are 2 of 120,620 tph and 154,935 tph, zone L of 135,351 tph, zone M of 138,313 tph, zone I of 189,709 tph. And constraints on the crusher during a month that also affect obstacles in rehandling include schedule time with a total time of 176.72 hours, breakdown time with a total time of 4.84 hours, unscheduled time with a total time of 154.62 hours.

Landslides or commonly called landslides are a disaster that often hits areas with tropical climates. The damage caused by landslides is most dominantly structural damage such as damaged road sections that are cut off. At the research location, there was a landslide that resulted in the obstruction of the road flow which was originally two lanes to one lane, it is feared that landslides will occur again, so one of the landslide prevention techniques is to use retaining walls. Based on this, this study is deemed necessary to determine the slope safety factor and to determine the safety of the slope after using retaining walls. The purpose of this study was to determine the level of slope safety without being given a load, the level of slope safety after being given a load of 25 Kpa and the level of slope safety after being given a load of 25 kpa and the addition of a retaining wall on the research slope using a Retaining Wall. In this study using the Finite Element Method in the calculation to find the level of safety of a slope, the researcher used the help of Plaxis 2D V20 Software, and the results of the calculation obtained a slope safety factor of 1.31, after being given a load of 25 kpa the slope safety factor was 1.14 and after being given a retaining wall the slope safety factor increased to 2.46.