The so-called open-pit mine was actually a very large mine pit. At this point, the mining methods were still rather crude, directly igniting explosives within the pit. When the explosives were detonated, the ground would split open, and then survivors were arranged to collect the resources.
The vast open-pit mine was divided into four areas, with mining taking place simultaneously in each. Once the four pits reached a certain depth, the collectors from all four areas would collectively retreat, then explosives would be placed in the central area. After detonation, they would collect the ore from the central region.
After understanding the collection process here, Dong Tianyu found his father, Mr. Thompson, in a tent near the mine pit. Mr. Thompson was leisurely playing cards with a few officers at that time.