If the notice filed with the district or municipal court, as aforesaid, shall state that the excavation, shaft or hole has been abandoned, and no person claims the ownership thereof, the court shall notify the county legislative authority of the location of the same, and they shall, as soon as possible thereafter, cause the same to be so fenced, or otherwise guarded, as to prevent accidents to persons or animals; and all expenses thus incurred shall be paid as other county expenses: PROVIDED, That nothing herein contained shall be so construed as to compel the county commissioners to fill up, fence or otherwise guard any shaft, excavation or hole, unless in their discretion, the same may be considered dangerous to persons or animals.