Help ; Drilling problems in Chert for Slope Stability studies

[JENG]

Will welcome suggestions on approach to drilling/coring in formation with interlayering of clay and chert. We have cored ~ 40 feet in chert and get stalled by presence of voids in chert formation with loss of drilling mud and cuttings falling back in the borehole. Still need to go down at least another 25 feet

 

[derubertis]

A technique that might work in your application is sonic drilling.  You can inquire by contacting Boart Longyear at the office nearest to you.  The office with which I am familiar is located in Otis Orchards, Washington, 509-926-9576.  Ask for Bob Buto or John Sine.