How deep can you drill?
There is no easy answer for this question, because of the inherent variations in subsurface conditions and circumstances. With our equipment It can range from 6-7 feet with the Pionjar in a very hard, dry, clay till material to over 50 feet with the Big Beaver and Mini-Mole in more ideal conditions.
With the Pionjar drill, the PEP, and the Rota-Hammer, you are generally restricted to depths of less than 15-20 feet. In very hard materials you may reach refusal much sooner.
The Big Beaver and the Mini-Mole are generally more suited to depths greater than 10 feet, because there is more equipment required and longer set up time to use it, but you greatly increase the penetration ability with these drills over the hand held percussion units. The Mini-Mole and the Big Beaver use a 140lb hammer to pound a 2″ split spoon connected with AW rods – this is the same process as a conventional geotechnical/environmental truck mounted drilling rig. Therefore the ability to penetrate soils with the split spon is identical to a regular rig. The Big Beaver though, does not have the weight (~700lbs) or engine power of a truck mounted rig for the augering process; therefore it is not as powerful for the augering component of drilling. While the Mini-Mole has approximately 5 times the weight and power of the Big Beaver, it still does not match the substantial power of the CME55 and CME75 truck mounted drills commonly used in Southern Ontario for areas of unlimited access. These drills (particularly the Big Beaver) may be restricted if significant rocks or rubble is encountered. The penetration ability will also depend on the size of auger used and whether it is a solid stem or a hollow stem. The most common application for the Big Beaver and Mini-Mole is drilling holes between 10 and 25 feet deep, though we have drilled holes to 55 feet in ideal conditions.
Therefore the short answer to the question of depth is: it depends!
Drilling FAQs