Although the excavation of the frozen ground is progressing slowly at the moment, it is still within Zhang Chen's tolerance range, and he can accept it. He is still young, and he has plenty of time. He can afford to wait! Moreover, he has not sat idle; he is thinking of other methods.
Zhang Chen collected firewood and only ignited it in the pit on his way home to observe the effect the next day.
"The underground space is quite sealed, the fire burns for a long time, and the heat accumulates for a long time. Once the fire starts burning, it's no different from a kiln. Even the coldest frozen ground should be somewhat melted."
Zhang Chen took out the flint, first lit some moss, and only reluctantly exited the cave once he saw the pile of firewood burning.
