Reliable Welding Inspection for Welded Structures in Mining Equipment14 September 2018
It’s hard to imagine a more abrasive environment. Grizzly screening bars and primary feeder chutes are experiencing a high-volume load as it exits a bank of mining equipment. The rocks are coarse, incredibly rough-edged, and they’re subjecting the alloy-reinforced equipment to almost unendurable levels of mechanical force. Fasteners are destroyed in a few short days by the heavy mineral aggregate, yet weld seams keep right on performing as the ultimate equipment glue.
Reliable Weld Inspections: Mining Equipment
Approaching the scene from another vantage point, we see the sad truth: bad equipment welds spill aggregate material. The high-velocity stream simply tears them apart. Meanwhile, the welding inspection is getting underway. The team notes the effects of fatigue loading, tests abraded seams for mechanical integrity, and carries out several non-destructive weld assessment routines. The job, as always, is to ensure the welds are capable of handling a nominated load, plus, at least in this case, the abrasive impacts that accompany that load fatiguing effect.
Stronger Than All the Rest
When it comes to toughened mining equipment, metal fabricators source carbon-toughened steels. Oftentimes, their surfaces are coated in chute liners, so the aggregate impact and abrasive force are dampened. Welding inspections look beyond this dampening material, for those replaceable liners could be concealing cumulative damage. The inspection documents crack initiation phases, studies fissures as they propagate along productivity-critical pathways, and concludes in a tough but unbiased decision. Granted, the decision could cause the mining equipment to be taken out of service, but this option is still less costly than a complete fatigue-related system collapse, one that was caused by a nearly invisible weld defect.
Battling the Shakedown Effect
Think of the rocky streams in a mining complex as equipment aging engines. The accelerated effects of the rattling, impact-shocking aggregate are hard to manage, although plastic liners, reinforced with engineering plastics, do mitigate the fatigue loading factors. Principally, though, it’s the indented marks, developing seam splits, and abrasive patterns on the welds that receive the most attention. Those liners and plastic screens are all replaceable, after all, but the mining equipment is there for the long haul. As such, reliably conducted weld quality audits are a common practice in mines.
Life on the front line, that’s what a welding inspector can expect when descending into the bowels of a mine. It simply wouldn’t be realistic, not down there, to leave a needed instrument or tool on the surface. Expect mine-savvy engineers to plan their weld auditing activities before they ever step foot inside this harsh and abrasive environment.
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