Augering pier holes with 305e2 Cat

We run a Cat 305e2 that we use for site work for custom homes. Recently we got a request to drill pier holes for some CMU retaining walls. This would be a new scope for us and am looking for any advice. The pier holes will be 18'' diameter by 12 feet deep. We have a Cat 19b auger motor that we have used to drill post holes. So I guess the main question is, will the 305 handle this job. Oh yeah the soil is a silt clay down to about 5 feet then weathered serpentine shale. and how do you get...

Augering pier holes with 305e2 Cat

Augering pier holes with 305e2 Cat