In line with its indicative offer, IMIC has tabled a bid of 120 pence a share, 80 pence of which is in cash.
There is also a two-year convertible loan note component with an 8% coupon, which is valued at 40 pence a share.
The deal is priced at more than double the 10-day volume average weighted price of shares of Afferro, whose major asset is the 2.5bn Nkout iron ore deposit in Cameroon.
Afferro chairman David Netherway said: "We are pleased to have reached this point with IMIC.
"We believe that the deal offers our shareholders a unique opportunity to realise value, particularly in light of broader market conditions.
"The acquisition has been structured to provide a significant cash element, and also a deferred element, as IMIC makes progress to provide a robust infrastructure solution for our flagship Nkout Project."
IMIC, with its close ties to African Iron Ore Group, run by Afren founder Bert Cooper, plans to become the continent's preeminent provider of infrastructure to countries such as Cameroon and has relationships with the end users.
And its links with some of China's largest steel companies and traders means it will have a ready customer base for the output from the Afferro developed 2.5bn-tonne Nkout iron ore deposit in Cameroon if the deal goes ahead.
IMIC chairman Haresh Kanabar said: "I am delighted that Afferro's board has acknowledged the rationale and attractiveness of our offer by recommending it to Afferro shareholders.
"The combination of IMIC and Afferro is a compelling opportunity that brings together Afferro's iron ore assets with IMIC's innovative infrastructure, financing and offtake solution."
Disclosure: I have no positions in any stocks mentioned, and no plans to initiate any positions within the next 72 hours.