Sanford Lab CSI: a case of bad vibrations

The water level continues to drop in the Sanford Underground Laboratory?down to 5,679 feet underground this morning, which is just 6 feet higher than the low-water mark set earlier this year before the deep submersible pump failed. 

That submersible pump was replaced in August, but now a large, rebuilt Ingersoll Rand pump on the 5000 Level is ailing, barely two weeks after installation. The troubleshooting, which continues this week, illustrates how our experienced, creative technical staff keeps the lab running safely and on budget.

Facilities Technician Rich Ellison first noticed the oil in the pump had prematurely blackened. Then he noticed a faint but odd sound? ?kind of like a ?grrrrrrr.?? 

?Rich is super-tuned to stuff like that,? says Planner/Scheduler Kirby Denton. Ellison spent 24 years maintaining pumps and hydraulic systems at Merillat Industries in Rapid City before joining the Sanford Lab nearly three years ago.

Following up on Ellison?s report, Project Engineer Mike Johnson tested the pump with an Emerson CSI 2120 Vibration Analyzer, which confirmed the bad vibrations. But the CSI didn?t solve the mystery.

?We?re still in the middle of troubleshooting,? Denton said. Frequent oil changes and a preemptive bearing change every week or two will keep the pump running safely until Sulzer Pumps technicians from a Denver service center can visit the lab. Meanwhile, a spare is available if necessary.

The Ingersoll Rand can pump 1,500 gallons a minute from the 5000 Level to the 3650 Level. Identical pumps on the 3650, 2450 and 1250 levels lift water in stages from the deep pool to the surface.

The rebuilt pumps were all donated by Homestake Mining Co. New pumps would cost hundreds of thousands of dollars, so keeping the current ones running is cost-effective. However, a newer pump, another rebuilt  Ingersoll Rand, is due for installation soon at the 3650 Level. Like the older pumps, it was a gift from Homestake.