After paying Cortadera's vendor $2 million in July, Hot Chili will now hand over a further $3 million, with another $10 million due within the next 12 months and $15 million in 24 months.
Cortadera is promoted as major global discovery showing "all the hallmarks of a company-maker".
The current fundraising, involving undisclosed new institutions plus existing backers Taurus and Hot Chili's chairman Murray Black, is being priced at A3.6c per new share, with capital markets firm Veritas acting as lead manager.
Planned exploration includes completion of a 15,000m reverse circulation and diamond drilling campaign.
Cortadera is 14km from Hot Chili's large-scale potential Productora copper development.
Shares in Hot Chili were up 3% to 3.8c in early trade, capitalising the company at $31 million.