by Al Price
In the summer of
2009, Dan Kelleher and Ken Borrell of the Midwest Geosciences group drove 20
hours from their home city of Waverly, Minn., to the University of Calgary in
Calgary, Alberta, to experience their first sonic borehole in Canada.
Midwest Geo was
offering one of its workshops on glacial successions for more than 50
geologists from Canada and the United States. The course teaches the principles
of sedimentary depositions, the effects of sedimentary weathering and the
methods to describe those elements on boring logs.
The workshop also
allows the university’s geological, engineering and environmental sciences
students to identify the same geological units in different boreholes in the
“The sonic drill
was awesome,” says Kelleher, a hydrogeologist and project manager with Midwest
Geo and co-founder of the company.
“The company that
actually drilled in Calgary was Crater Lake Drilling from Red Deer, Alberta,
working with personnel from Sonic Drilling Ltd. of Surrey, British Columbia.
The crew did a world-class job of carefully sampling and providing 100-percent
core recovery, which makes teaching sedimentary sequences much easier,” adds
First, the team drilled
a pilot hole the day before the course, to better understand the geology of the
region. Next, for the instructional hole, Kelleher had the sonic rig drill down
100 feet. The continuous core then was placed from end to end on a table,
enabling them to analyze it, and read the story of the sediments below.
“The soil core is
remarkable when inspecting it in this manner,” says Kelleher. “The sedimentary
story is so much easier to read and the geologic history is apparent, even to
those without a science background.”
Developed by Ray
Roussy, president of the Sonic Drill Corp. and Sonic Drilling Ltd., sonic
drills use water instead of drilling mud to case the hole. Looking much like a
conventional air or mud rotary drill rig, a sonic can be easily recognized by
its drill head, which is slightly larger than a standard rotary head. It is
this drill head that allows rapid drilling through most geological formations
through a combination of forces including rotary motion, oscillation and vibration.
In environmental investigations like the Calgary workshop, high sample recovery
rates combined with large sample volumes increase subsurface resolution.
“The sonic’s wide
sample diameter of 4.5-inches allows for large-volume samples,” says
Kelleher. “That is priceless when
geologic conditions are comprised of buried large gravel and cobbles. Plus, the rapid sampling rate often does not
reduce the sample recovery, yielding financial benefits for appreciable-sized
Although the Calgary instructional hole was
drilled only to 100 feet, sonic drill rigs are capable of providing
uninterrupted core samples to 300 feet and beyond.
Sonic Drill Helps Students Reveal Glacial Secrets
January 22, 2010