The terms of the deal were first set out in a memorandum of understanding in August.
READ: Caledonia Mining declares quarterly dividend, remains on track for full year payout of US$0.275
In total the transaction is worth US$16.667mln, and includes the cancellation of an US$11.67mln loan and the issue of just over 725,000 shares at a price of US$7.15, the prevailing price at the time the MoU was agreed.
On completion of the transaction, Caledonia will have a 64% shareholding in Blanket and Fremiro will hold 6.42% of Caledonia's diluted equity.
Separately, Caledonia has moved to reassure investors that the ongoing shortage of foreign exchange in Zimbabwe has not impacted operations at Blanket. The company said it is in touch with the highest levels of government in Zimbabwe, and that the matter is receiving urgent attention.