Development of an appropriate maintenance strategy for excavators operating at Ilgin Çavuşçugöl lignite mine

This study aims to determine the optimum maintenance strategies and maintenance intervals for the excavators used in the Ilgın-Çavuşçugöl Lignite open pit mine. Within this scope, failure data, maintenance–repair durations, failed components, production losses due to downtime, spare part replacement costs, and maintenance costs of four excavators (H1, H2, SM1, and SM2) operating in the field between 2019–2022 and 2019–2025 were monitored. Statistical analyses were conducted using the failure data of the body–engine, undercarriage, boom, and bucket components of the excavators to identify the most suitable probability distribution type representing the failure behavior and to estimate the corresponding parameters for each excavator. Based on the determined distribution parameters, the time between failures was modeled using Monte Carlo simulation. To evaluate the consistency of the simulated data with the actual field data, descriptive statistics such as mean, standard deviation, skewness, and kurtosis were calculated, confirming the validity and reliability of the simulation results. Based on the developed simulation model, optimum maintenance strategies for the excavators were analyzed. In 1–5-year operation scenarios, different maintenance intervals (ranging from 3 to 12 months) were tested, and failure maintenance costs, planned maintenance costs, and total costs were calculated for each scenario. The results revealed that the failure behavior of the excavators varied depending on the component type. Optimum maintenance intervals were found to range between 7–11 months for body–engine components, 3–5 months for boom components, and 4–9 months for bucket components. In one-year maintenance planning, total costs remained relatively low, as the limited number of failures helped keep expenses under control, while planned maintenance costs were the dominant factor. However, in 2–5-year maintenance planning, maintenance costs increased due to the rising number of failures, and the addition of overhaul costs led to a cumulative increase in total expenses. This finding indicates that as the equipment ages, wear intensifies and maintenance costs inevitably rise.