Minereset plugin causing Chunks to reset

Hello,

on my prison server after random intervals chunks reset back to the original state - meaning the mine and buildings are back to grassyhills. Now those chunks always happen to be right next to the mines that reset every hour so I assume the plugin might be causing this issue.
Images of reset Chunks that reset:
001 | 002 | 003 | 004 | 005 | 006

Source to my Minereset Plugin​

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So if anybody could take a look at the source to see if something is broken there I'd be very happy. (Please not the plugin isnt written very nicely - it was my 2nd plugin I made. Also if you find anything that isnt very effiecent in the code but doesnt have to do with the chunk resets I'd be happy for help there too )​