The management of physical resources in an organization involves several processes related to innovation and continuous improvement. For this reason, the proper study of the reliability and maintainability analysis is considered essential and is treated as one of the main pillars for decision-making at the tactical and operational levels. This paper proposes a useful support tool for decision-making in the field of maintenance management and reliability analysis, so that such decisions remain aligned with the vision, strategy and economic indicators of the business or industrial organization. This research clearly shows how the variability of different load levels (inflows) on the grinding lines, affects the reliability of a specific sulphur plant (located in Chile), determining after that, what the optimum load should be. The paper identifies the relationship between each line load ranges and the corresponding reliability, all through the development of a real case study conducted in a mining company located in northern Chile.