E5 Equipment reliability and availability

Topic

In mining construction, an activity typically relies on a combination of machinery and auxiliary equipment. An excavator, crane, pump, or transport unit may have a high nominal capacity, but that capacity only contributes to the project as long as the equipment remains operational and capable of performing its intended function. This model explains how failures, degradation, repairs, and maintenance policies shape available capacity over time.

Each piece of equipment serves a specific role within a workflow. Sometimes, the stoppage of a single auxiliary component is enough to halt the entire process, even if the primary machinery remains operational. Understanding this interdependency requires more than just knowing the quantity of equipment on hand; one must also consider compatibility, capacity, location, operational condition, and how each unit relates to the others. Continuous operation leads to wear and tear; furthermore, unforeseen failures can occurthe frequency and severity of which depend on the equipments history, the operating environment, and the conditions under which it is used.

When a piece of equipment fails, the resulting loss in productivity extends beyond the time spent on repairs. The process may first require identifying the issue, safely halting operations, diagnosing the root cause, securing technicians, obtaining permits and spare parts, performing the necessary work, and conducting tests before the equipment can return to service. A relatively minor breakdown can lead to a prolonged period of unavailability if a specific part is missing or if the equipment is located in an area that is difficult to access. Therefore, it is essential to distinguish between the root causes of failure, waiting times, the technical work itself, and the actual restoration of capacity.

Preventive maintenance introduces a significant trade-off: taking a machine out of service for inspection reduces immediate capacity, yet it may lower the risk of a longer, unexpected breakdown later. Postponing maintenance might temporarily boost apparent performance, but it risks compromising future operational continuity. Other options include backup strategies, alternative equipment, or changes in methodologythough these are only effective if they can be deployed in time and are not susceptible to the same failure causes. The cost of maintaining such redundancy must be weighed against the vulnerability it aims to mitigate. Monitoring requires recording hours of use, symptoms, failures, severity, interventions, spare parts, scheduled maintenance, actual availability, and the impact of each stoppage on production. The simulator allows for the comparison of different scenarios: one with preventive maintenance, another with deferred interventions, and a third involving backup equipment. It tracks periods of operation and downtime, the resulting loss in production, and the consequences for the completion of a given activity. The simulated failures serve as illustrations; generating reliable risk estimates for an actual fleet would require historical records and calibration. The demonstration aims to show that equipment availability is a dynamic process, rather than a fixed percentage that can be taken for granted.

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