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).
 

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.