However , its proximity to both Fukuoka City and Kitakyushu City cushioned the effect of the coal industry shutdown and kept the local economy from going into freefall .
Since the coal mines closed , Iizuka City has suffered from a consistently declining population base .
Iizuka City 's proximity to both Fukuoka City and Kitakyushu City cushioned the effect of the coal industry shutdown and kept the local economy from going into freefall .
Since the coal mines closed , Iizuka City has suffered from a consistently declining population base .