With Bergerson-Caswell Inc. struggling to set a tremie line through the annular space of the boring on a late September 2020 project, David Henrich, CWD/PI, CVCLD, turned to his industry resources.
“I read Marvin’s (Glotfelty) book (The Art of Water Wells), talked to a few of my friends, and successfully grouted an 8-inch well in a 12-inch hole on a project we had been having nothing but trouble with,” says Henrich, president of Bergerson-Caswell in Maple Plain, Minnesota, and the 2018 president of the National Ground Water Association.
While installing a 295-foot Darcy heat exchange well (500-plus gallons per minute) for the Pipefitters & Steamfitters Union Hall in St. Paul, Minnesota, Henrich opted to use the braden-head grouting method for the first time. The project was becoming a head-scratcher for Henrich’s drilling crew as the glacial tills seemed to be causing the bore to have an irregular path.
“Even though we were using a freshly built-up stabilizer, we still were having issues setting a tremie line through the annular space of the boring,” Henrich explains. “After dealing with a plugged-up grout line on the first boring, we started exploring other options.
“After talking with an industry friend and reading Marvin’s book, it was apparent that there was a much easier way to install our grout.”
Henrich says any of the displacement methods would have worked, but the braden-head method seemed like the easiest for his company to build and use in a short time. Henrich’s industry friend provided pointers on how to build an assembly, and within a couple of hours, the company had a new grouting tool ready to go in its shop.
“Considering our grouting time was cut by three quarters, I would say that I got some sound advice,” Henrich says. “The overall process was much easier than using a tremie line and was much less time consuming. Since you don’t ever have to pull any pipe—like you would during a tremie grout job—you can continuously pump grout until the boring is filled. Since the grout is continuously pumped from the bottom of the boring towards the top, the grout seal is arguably as solid as it possibly could be.”
An inspector from the Minnesota Department of Health was initially reluctant about the company using the braden-head method, mainly because it was Henrich’s driller’s first time executing the process. But Henrich says “he (the inspector) seemed somewhat impressed by the time we were finished even though we had to top off that specific boring the next day.”
“The boring took an excessive amount of cement which went well beyond our expectations and our safety factor,” Henrich continues. “Once we switched over to using cement trucks and a commercial cement pump, the process only took about an hour to complete. Once the cement was pumped in, we could actually drive the pipe into the bedrock which made for an incredibly good interface seal.”
Henrich says the first night the company finished at 10:30 p.m., but it had to manually mix 2½ pallets of cement. “Had we known that we were going to need 2½ times the bore volume, we would’ve called a truck in from the get-go,” he says. “Once we switched to trucks, the process went very quick.”
Bergerson-Caswell will more than likely use the braden-head method anytime it needs to pump two or more yards of cement. Henrich recommends finding someone who has used the method to get their input before giving it a try.
“Make sure you have all the steps planned out and then execute,” he says.
To learn more about the braden-head method, read the Water Well Journal’s “Drawing from the Well” column.
—By Mike Price