This is the 8789th most frequent Polish word.
rudnik
"Rudnik" means "mine" or "a place where minerals are extracted."
The word 'rudnik' here refers to a mine for extracting ores.
Ten rudnik wydobywa żelazo od stu lat.
This mine has been extracting iron for a hundred years.
Again, 'rudnik' is used to denote a mine where minerals are extracted.
W okolice rudnika zwykle jest pełno ciężarówek transportujących surowce.
Around the mine, there are usually many trucks transporting raw materials.
Here, 'Rudnik' refers to a proper name, a town in a specific region.