Coal mining The town remained modest until the early 20th century, when several mines were opened (including the Emma), caused a substantial increase in population. This necessitated the construction of new residential areas, with the result that
Heerlen & Hoensbroek grew closer to each other.
Today Hoensbroek &
Heerlen now form a contiguous and built-up area. Only the tip, the former Oranje Nassau III mine, currently designed as a park, represents a kind of barrier between the towns. The mines in the area are now all closed, but many of the workers before landscaped areas still exist. ==Transport==