Directional drilling used in Mississippi River crossing

Tennessee Gas Pipeline Co. recently completed its longest large-diameter directional bore and pulled nearly 3,000 feet of 20-in. replacement pipe under the Southwest Pass of the Mississippi River. The replacement was necessary to allow for planned widening and deepening of Southwest Pass. This article explains why conventional dredging methods were not possible. It then explains how the directional drilling was done. Given favorable soil conditions such as found along much of the Gulf Coast, the speed of installation, environmental consideration of dredging eliminated, and the cost-competitive posture Tennessee found among the directional drilling contractors, Tennessee plans to utilize this technique increasingly in the future.