The 712MT micro trencher features a unique automatic wheel drive propulsion system. This trencher utilizes a load sensing hydraulic valve to adjust the trenching wheel speed to the load on the digging chain. The automatic adjustment to the wheel speed eliminates the responsibility on the operator to constantly adjust their wheel speed. One control lever operates the wheel drive and one lever operates the chain drive. This machine is designed for digging trenches in "normal" ground of reasonably soft dirt and stones up to 3" (15cm) in diameter. Ground that is extremely hard packed, contains larger stones, high clay content or is in a very dry or frozen condition may be unsuitable for normal trenching. Consider using a larger trencher, backhoe or other heavy equipment for such conditions.