In the Southeast we have used, and modern day well diggers use, reinforced concrete pipe sections (2.5-3 feet in diameter and approx. 2 feet high) to dig wells. After you have excavated 3 or 4 feet, you need to place a platform with a wench over the hole and begin placing pipe sections. As you dig, the pipe sections slide downwards, providing an iron reinforced concrete well lining as you go. The sections interlock, come in a variety of diameters, are a lot cheaper than heavy equipment, and allow you to go to at least 45 feet (which is what we did in one well). A 45 foot vertical column would be next to impossible for a backhoe. Tom Wheaton