Board Thread:Questions and Answers/@comment-5842496-20140706094700/@comment-5840147-20140706154334

You can only expand from mining 20 times :/ so if you've collected enough of the little island pieces and expanded 20 times it doesnt let you use the expansion part of the mine because you've already maxed out your expansions. They have already once added to the amount of times you can expand (used to be 10 now its 20) so maybe some day they will add more expansions so you can use the expansion part of the mine but until then im afraid you cant use it :( next time stop expanding before you get to the last one (for example if the max it 20 times, then stop expanding when you expand 19 times so you can continue to use it)