DRILLING FLUIDDuring the hole drilling process a drilling fluid is used. The most important functions of the drilling fluid are:• Loosening the soil in front of the bit,• Providing power to the drill bit via the jetting action,• Lubrication of the drill string and BHA,• Removal of soil particles out of the hole,• Keeping the soil particle sin suspension,• Stabilization of bore hole wall.The proposed drilling fluid for this project will comprise Bore-Gel, a propriety single sack boring fluid specially designed for use in HDD which provides optimum gel strength with minimum viscosity for cutting suspension and transport. It improves borehole stability in poorly consolidated sand and gravel formations and reduces filtration by providing a thin filter cake with low permeability. Bore-Gel is mixed with potable water to achieve the required fluid properties for the ground conditions being drilled through. If required, additional additives will be available on site to enhance the carrying capacity of the fluid to remove cuttings from the drilled hole and to prevent bit balling halting progress.