The utility model provides a mining damp formula patching machine material loading mouth subtracts dirt device, includes dust cover (1) and bucket formula bush (2), is the dust cover including the cover body (1 1 ), filter sieve (1 2 )And shielding plate (1 3 ), the embedded upper end at the cover body of filter sieve, the one end of shielding plate is fixed in the junction of filter sieve with the cover body, the other end towards the direction downward sloping of bucket formula bush, and is the shielding plate personally experienced sth. Part of the body with the cover towards the one end ofbucket formula bush direction and is formed fore shaft (1 between the lower extreme 4 ) is bucket formula bush provided with the central through hole (2 that is parallelogram 1 ), the port size is unanimous down with the cover body for the central through hole size, and cover body bottom fixed mounting is on bucket formula bush. The device can prevent on the one hand that the thick liquids in the patching machine agitator tank from kicking up, reduces the on -the -spot dust concentration of patching machine operation, on the other hand, when patching machine delivery line blockked up, the device can prevent that the whitewashing material from in the twinkling of an eye from the blowout of patching machine material loading mouth, preventing that the spun thick liquids from causing the injury to operating personnel.