Hello, I have a lingering question regarding the calculation of system availability in the context of an underground mine with multiple ore handling systems. Specifically, I am looking into how to factor in the presence of buffers in the overall availability assessment. The mine has two main systems and an auxiliary system that hoist ore up through a central shaft. There are two methods we use to calculate availability: one involves using data on breakdowns, operations, idling, and preventive maintenance hours over a set period to determine availability. The other method considers Mean Time Between Failures (MTBF) and Mean Time To Repair (MTTR). For example, if we have 10 pieces of equipment in one of the systems (such as bins, conveyors, crushers), and we treat it as a series system where the failure of one component can halt production, the overall availability is the product of each equipment's availability. However, I am unsure about how to account for equipment like bins or ore passes that have capacity buffers. Even if the lower conveyor fails, the bin several levels above can still receive ore and remain operational. Should I exclude these buffers and focus solely on the mechanical equipment for availability calculations? While the bins and other components do undergo maintenance and occasionally experience hangups, they are still considered part of the system.
Hello AJ. While I'm not an expert in this area, it's important to have data for each individual capacity buffer. In order to calculate availability, you need to assign a redundancy factor to each buffer and then incorporate this into the overall formula. This formula combines parallel and series calculations using adjusted figures for each buffer. It is calculated as x1 * x2 * x3 * x4 * x5 * x6 * x7 * x8 * x9 * (time monitored - (downtime(bin1 + bin2 + bin3 + bin4 + bin5) * redundancy factor) / time monitored. This calculation assumes a uniform redundancy factor of 20% above. I hope this explanation clarifies things, but feel free to reach out if you need further assistance or information.
Incorporating buffers in your system availability computation is a sensible approach since they are part of your system and play a crucial role in its operation. While technically they may not cease functioning as often as other operational components, their unavailability can indeed affect the overall productivity. That said, you might want to consider a different method for calculating the availability of your buffering equipment, perhaps factoring in the frequency and duration of maintenance or hangups rather than purely breakdowns. Perhaps the use of a modified version of your MTBF/MTTR methodology taking into account the unique nature of these buffering components could work. And maybe, you could weigh these availability figures differently when combining them with the availability of other system components. It's all about representing the actual operational reality in your calculations as closely as possible.
Hi there! Determining system availability in a complex, multi-system setup like an underground mine can indeed be quite challenging. You raise an excellent point about the presence of buffers like bins and ore passes. Part of the concept of availability ties strongly to capacity utilization, so buffers do play a role. While it's true that a conveyor failure wouldn't immediately halt the reception of ore into the bin due to its buffering capacity, continuous failure of the conveyor would eventually prevent the overall functioning of the system once the bin is full. I’d suggest you should factor in the availability of buffer components but possibly with lesser weightage compared to crucial mechanical equipment. The weight assigned could be proportional to how critical they are in maintaining the flow of operations. Moreover, the role of buffers isn't just to maintain operations during equipment failure, but also during maintenance activities, so considering their availability does make sense even while calculating using MTTR and MTBF methods. This approach would provide you a more holistic perspective of system availability.
It sounds like you're dealing with a complex system there! When it comes to including buffers like bins in your availability calculations, a good approach might be to incorporate them as a separate factor rather than excluding them outright. Since they can maintain some level of operation despite mechanical failures downstream, treating them as part of a broader availability assessment could provide a more realistic picture of your system’s efficiency. You might consider simulating scenarios where some equipment is down while others (including the buffers) continue to operate; this could help you gain insights into overall performance and identify critical points in your process. Balancing the reliability of the buffer capacity with the mechanical equipment's reliability can give you a clearer view of availability in practice.
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Answer: - System availability in such mines can be calculated using methods that consider breakdowns, operations, idling, preventive maintenance hours, Mean Time Between Failures (MTBF), and Mean Time To Repair (MTTR).
Answer: - Buffers like bins and ore passes can complicate availability calculations as they may continue to function even if a lower-level component fails. Deciding whether to include or exclude buffers in availability calculations depends on their criticality to the overall system operation.
Answer: - While bins and other components with buffers undergo maintenance and can experience issues, they are still integral parts of the system. Deciding on their inclusion in availability calculations should consider their role in system functionality and potential impact on production.
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