borehole is advanced in a straight line. When the bit is advanced without rotation the borehole is deviated toward the untapered side of the bit. This technique allows the borehole to have multi-
ple points of curvature and to be brought back to the surface after traversing the area through which the well is to be placed. Well cas-
ing is installed by pulling the cas-
ing back through the boring. The UICD method is advantageous in two respects: it generates a mini-
mum of secondary waste, and it requires a small amount of drilling fluids, minimizing the prospects for interference with soil vapor extraction.

River Crossing Industry Drilling (RCID)

The river crossing drilling techno-
logy demonstrated used a slant rig and a steerable hydraulic jet drill bit. The bit consists of an off-center jet through which mud is pumped. The jet of mud cuts through uncon-
solidated sediments and the bit advances in the direction the jet is pointed, or the drill string is rotat-
ed to advance in a straight line. A mud rotary bit can be used to ad-
vance through consolidated rock. Drilling proceeds by alternately advancing the drill string and then advancing a washover pipe over the drill string. When drilling is