I have previously stated I have not been out as isolating, also I was saying if a tunnel inside was full up with sand then yes remove it their is nothing rong with that in my eyes if you already enter a cave / mine many tunnels are like that ,It is a very common thing to remove backfilled passages tunnels to enter deeper , I am not saying go equipped and start breaking in to new places atall if they are already inside wich they obviously are then yes after this virus buggers of by all means I say go and further explore if you have to remove some sand from a tunnel that has been filled in I don’t see a single problem