As you expand to left of the Mine, there are 52 (4?4) spaces to expand. Once you expand the last space, you will stop receiving Dynamite to Mine with.
Click image for larger version. 

Name:	Screenshot_20200406-025317_Dragon Story.jpg 
Views:	52 
Size:	78.3 KB 
ID:	55119
This Island, I expanded to the end.
Click image for larger version. 

Name:	Screenshot_20200330-235030_Dragon Story.jpg 
Views:	51 
Size:	76.7 KB 
ID:	55120
This Island, I never expanded the last last block, so I continue to get Dynamite to mine for food and coins.