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).
 

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.

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.

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.

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.

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.

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.

Dump truck tires are an important component in the operation of wheel-type units that require routine inspection because they directly affect the availability and performance of the transport equipment. In the OHT 777 type unit, six tires are used with a configuration of two tires in the front and four tires in the rear. This study aims to evaluate tire performance through the analysis of Key Performance Indicator (KPI) parameters, namely Ton Kilometer Per Hour (TKPH), Tread Utilization Rate (TUR), and tire life (lifetime), in order to assess the achievement of performance targets. The research method uses a quantitative approach with actual data collection in the field, including the preparation stages, primary and secondary data collection, data processing, and preparation of the final report. The data is processed to obtain the tire KPI value. The results of the analysis show that the TUR value for MICHELIN brand tires is 68.9% and BRIDGESTONE is 70.7%, still below the company's target of 85%. The TKPH value for the OHT 773 unit is 149 (with a TKPH rating of 207) and the 777 unit is 241 (with a TKPH rating of 514). The actual lifetime of BRIDGESTONE tires was recorded at 1,698.6 hm and MICHELIN at 2,268 hm, far below the target of 8,500 hm. Tire damage found included impact (23%), sidewall damage (18%), run flat (18%), bread damage (18%), sounder cut (14%), and foreign object puncture (9%). This evaluation is expected to be the basis for improving tire management, so that tire performance in the future can be more optimal and support the smooth operation of the unit.
 

Drilling is an essential operation in mining activities, particularly in borehole preparation for blasting purposes. The efficiency of blasting hole preparation depends significantly on the drilling speed to penetrate the rock formations.Drilling Rate Index (DRI) measures the ease or difficulty of drilling through rock formations. It combines two tests: Brittleness (S20) and SJ value. DRI serves as a common metric to predict drilling capabilities and is classified according to a table classification of drilling rate index.The classification of DRI values for sandstone and mudstone of Balikpapan Formation at PT. RCI Job Site ABK indicates a very high classification with DRI values ranging from 66 to 86. Testing results for samples SBP1 (DRI 75.9), SBP2 (DRI 81.7), SBL1 (DRI 66.6), and SBL2 (DRI 71.1) all fall within the very high classification range.