Glencore already has an offtake agreement in place for four million tonnes of annual production from Macarthur's proposed Lake Giles mine in Western Australia, over the first 10 years of the operation.
Macarthur plans to use note proceeds to advance Lake Giles through its bankable feasibility study phase this year.
Glencore joins Exception Capital as major participants in the note offer, with Exception taking a $1 million share.
Macarthur CEO Cameron McCall said he believed the agreed terms were attractive to both parties and provided the junior with funding certainty while minimising shareholder dilution.
Macarthur shares have tripled in value to C9c in Toronto since the start of 2019, taking the company's market capitalisation to $27.54 million.