1 Material and labor for a wood retaining wall runs approximately $20-$25 a square face foot (and there's usually a minimum charge for small projects), which would be about $1,000-$1,300 for a 50-square-face-foot wall. Materials and installation for a stone retaining wall start around $25-$40 a square face foot and go up depending on materials, site conditions, and other factors.
MFWD (mechanical front wheel drive) or front wheel assist tractors generally have smaller tires on the front and the front axle can be mechanically disconnected from the rest of the powertrain in some manner or another.
Measurement While Drilling (MWD), also known as Logging While Drilling (LWD), is a measurement taken of the well bore (the hole) inclination from vertical, and also magnetic direction from north. Using basic trigonometry, a three-dimensional plot of the path of the well can be produced.