BHP has put a secret change of control clause in the contract that gives it rights to all the nickel produced by Mincor Resources, setting up another potential complication for Andrew Forrest as he mulls whether to spend $760 million to acquire the company.

Wyloo’s proposed acquisition of Mincor was rocked last week after the nickel producer said it was struggling to meet the product quality standards demanded by BHP. The disclosure blindsided Wyloo and prompted it to review legal options, including whether to seek permission from the corporate regulator to withdraw the March 21 offer that compels it to buy Mincor shares on market when offered at $1.40 per share.