Heavy pitch fully mechanized coal mining face open-off cut pilot drilling construction method

The invention discloses a heavy pitch fully mechanized coal mining face open-off cut pilot drilling construction method. The method comprises the steps of carrying out drilling and hole expanding, rod removing and wall protecting and fixedly steering for forming a coal discharging channel. In the drilling and hole expanding step, waste rock drag in a drill hole is removed pneumatically, jamming of a drilling tool is effectively prevented, a wall protection sleeve is made of an iron sheet with the thickness ranging from 2.5 mm to 3.0 mm, the internal diameter of the wall protection sleeve is 480 mm, the length of the wall protection sleeve is matched with the length of a drill rod, and joints can be connected and fixed through the cooperation of an iron clamping plate (a steel plate with the thickness being 8 mm) and a bolt with the M equal to 16 mm and can also be connected through rabbets. The construction method further comprises the step that a steel barrel with the hole diameter being 450 mm and the length being 1.5 m is embedded in the wall protection sleeve, the impact resisting strength of the wall protection sleeve is improved, a steel wire rope with the diameter being 15.5 mm and the length being 2 times of the coal discharging channel is installed in the channel, a rope clamp is fixed on the lower section every 10 m, the rope is coiled and stored at the appropriate position of a machine lane, and the upper end of the steel wire rope is fixed to a special air way winch for dredging the coal discharging channel later.