Sonic vs. auger drilling: which method your site actually needs

"Which drilling method should we spec?" is one of the most common questions we get from consultants — and the honest answer is: it depends on your site, not on what the driller happens to own. That's exactly why we run both.

Here's how sonic and hollow-stem auger really compare, in plain terms, so you can spec the right one.

The short version: auger is fast and economical for routine shallow work in soft soils. Sonic gives you a cleaner, continuous core, goes deeper, and powers through gravel, cobbles, and fill — for a higher day rate. Match the method to the ground and the data you need.

Hollow-stem auger

Auger is the workhorse of Lower Mainland environmental and geotechnical work. A hollow flighted stem turns into the ground and doubles as temporary casing, so you can drop samplers or set a monitoring well right through it.

It shines when:

• The soils are soft to medium — the sands, silts, and clays that cover most of the Valley.
• You're staying relatively shallow (roughly the top 20–30 m, ground depending).
• You want split-spoon SPT samples and a cost-effective hole.
• You're installing shallow monitoring wells.

It struggles when:

• You hit gravel, cobbles, or dense fill — refusal comes early.
• You need a continuous, undisturbed core.
• You're going deep.

Sonic

Sonic uses high-frequency vibration to advance the casing and core barrel. It gives you a continuous core in a sealed liner and pushes through the material that stops an auger cold.

It shines when:

• You need a continuous, high-recovery core — a full picture of the profile, not just sampler intervals.
• The ground is difficult — gravel, cobbles, till, or fill near the Fraser or on old industrial sites.
• You're going deeper than auger comfortably reaches.
• You want less waste soil to characterize and dispose of on a contaminated site.
• Speed through tough ground matters — sonic is often faster where an auger would grind.

The trade-off: a higher day rate. On easy, shallow ground, that premium isn't buying you anything auger wouldn't.

Side by side

How we'd actually decide on your site

We look at three things: the soils you expect, the depth you need, and the data the report has to defend. Routine geotech borehole in Valley silt to 15 m? Auger, every time. Chasing a plume through gravel to 30 m with a continuous core? Sonic earns its rate. A lot of sites are obvious once we talk them through — and a few genuinely go either way, where we'll tell you the cheaper option is the right one.

That's the advantage of a driller who owns both: the recommendation isn't shaped by which rig is sitting in the yard.

Getting the rig to your site

We're owner-operated and we bring the rig to you — across the Lower Mainland and the Fraser Valley. If you've got a scope coming up and you're not sure which method to spec, send it over. We'll give you a straight read on which one your site needs before you commit to a day rate.