Dec '12/Jan '13

From reactive to proactive

Intelligent approach to inspections finds its niche in mining

By Alexandra Lopez-Pacheco

Mosaic’s mechanical integrity inspections go far beyond regulatory compliance | Courtesy of The Mosaic Company

Mechanical integrity risk-based inspection has been central to maintenance in the oil and gas industry for years, “but it’s almost unheard of for the mining industry,” says William Minter, client solutions engineer for Pinnacle AIS. Pinnacle, a Houston, Texas-based firm, is hoping to change that; it specializes in asset integrity management, engineering consulting services and asset management software. The Mosaic Company was one of the first mining companies to seek out Pinnacle’s expertise.

Mosaic’s new risk-based inspection program, unlike those rooted in regulatory compliance, is based on assessing risk for every stationary and structural asset in the mine. “Today, inspections are not required for all assets, only regulated ones, so you find facilities that may have never inspected many assets – sometimes more than half of their assets in the field,” Minter says. On the other hand, “risk-based inspections are performed for all assets at a facility, so all are included,” he adds.

According to Minter, mining companies have lagged in adopting risk-based mechanical integrity programs for a number of reasons. Traditionally, mines have been built with a life expectancy of 30 or 40 years, which is relatively short. But with today’s advances in processes and technologies, and a growing economy, mine life cycles are being extended indefinitely. In addition, the consequence of a common failure in the mining industry is very different from one in the oil and gas industry. Even one small malfunction can mean immediate, major problems in the energy sector. “Leak-type failures in a refinery can easily lead to a fire or even an explosion,” Minter explains. “Catastrophic failures can cost lives and get the ­attention of both regulating bodies and the media. In the mining industry, the most common failures typically don’t get that attention because the failures aren’t catastrophic – if a pipe is leaking, it’s likely only leaking water.”

What has been overlooked in mining, says Minter, is that common failures can trigger a ricochet effect, with one small failure affecting other assets and leading to more serious failures, which can result in lost production time if a shutdown for repairs is needed. In some cases, a catastrophic failure can result in injury of personnel in the area.

Every risk measured

Failures of major assets in potash and phosphates led Mosaic’s management to look at a new system for safety inspections. However, they were not the only forces driving the change, says Lorne Huyghebaert, former manager of mechanical integrity at the Mosaic Potash business unit. “Over the long term, it makes you a more cost-efficient company,” he says. “As well as being safer, when you inspect your assets in the right places at the right frequency, you have less surprises to react to.”

With help from Pinnacle, Mosaic is in the process of computing a number value for every potential risk that exists: nothing is left in the margin. “There are a lot of failures that can happen before the catastrophic ones,” says Minter. “So we want to look at the most common and likely failures, like a beam buckling, which is an early indication that the roof might collapse eventually.”

The risk-based mechanical integrity system looks at both the consequence and probability of failure. “The consequence of an asset failure is specific for each individual asset,” says Minter. “We consider consequence to health and safety, environment, public image and economic loss.” The probability of failure is based on a degradation study that identifies what will cause an asset to fail, and the likelihood of failure, he notes. “We not only know when to inspect an asset, we also know how and where to inspect that asset. The degradation study also tells us who should inspect that asset; for advanced inspections, we need to use a specific type of inspection personnel.” Highest-risk assets get inspected first.

According to regulations, an ammonia storage tank would require a simple five-year external visual inspection and a 10-year internal inspection. “Aside from these regulated inspections, a company may have no idea how to inspect, when they should inspect, where to focus inspections, and who should be hired to perform the inspections,” says Minter. Now, at Mosaic, each individual ammonia tank will have inspection schedules that fluctuate over time, adapting to changes in the field.

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