Image Number 14 for United States Patent #4691788.
A lateral hole boring method whereby a lateral hole of a desired length is formed underground by repeatedly performing the following steps. A vertical hole is prepared, and a lateral hole boring apparatus equipped with a leading auger of a smaller length than the diameter of the vertical hole is lowered into the vertical hole to a predetermined position. The apparatus is manipulated from the ground level to advance and rotate the leading auger to bore a lateral hole. When the lateral hole has reached a predetermined length commensurate with the length of the leading auger, the advance movement of the leading auger is stopped, and the lateral hole boring apparatus is manipulated from the ground level to detach the leading auger therefrom, and is lifted above the vertical hole while leaving the leading auger in the lateral hole. A coupling auger of a smaller length than the diameter of the vertical hole is attached to the lateral hole boring apparatus outside the vertical hole, and the apparatus is lowered into the vertical hole again. Then, the lateral hole boring apparatus is manipulated from the ground level to couple the coupling auger to the leading auger left behind in the lateral hole.
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