OD (Overburden Drilling) CASINGS
OD (Overburden Drilling) is a system for top hammer drilling with a "standard” inner drill string, usually a T38, T45, T51 or 88, 9 rods, as well as an outside tube, (OD-tube). You will have the possibility to drill the outer tube (casing) first, and then drill out with the "normal" inner drill string, or to drill both inner and outer at the same time. If you choose to drill both at the same time you simply connect the rods and tubes at the flushing head and the flushing/ejection bell. This system is a retrievable method where you use the rods and tubes over and over again. All joints are threaded.