Below the tall building in Zaozhuang is a coal mine.

When designing a building, a feasibility study report or preliminary design shall be issued. If what you say is true, it means that there are obvious defects in engineering design.

According to what you said, if there is a small coal mine, it should be a private small mine, which is a legacy of unsound policies and systems in the early stage. Any regular ore field must carry out geological exploration in the area where the ore field belongs. There are protective coal pillars around villages, factories and roads in the ore field, and the scope is strictly regulated.

The cement column you mentioned is called "pile foundation", which is the foundation that must be laid for high-rise buildings. This is very important. To solve this problem, you'd better have actual evidence and call the police. Even if there is no coal seam under the building, it is a serious engineering quality problem that the pile foundation is not driven.

I estimate that the coal they said was left by the former residents (probably), even if the coal seam exposed by the open pit mine is below 50m. If you say that you can find the coal seam by driving a pile foundation of 20-30 meters, your place has already become a world-famous open pit mine and a national key energy production base, far exceeding the major open pit coal mines in China.