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.

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.

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.