This is how it is done ...

ASX-listed potash upstart Kalium Lakes has called in Macquarie Capital's bankers to help prepare the company for the final piece of a $200 million-plus funding puzzle.

Expectations are that Kalium Lakes could be cap in hand in front of fund managers seeking up to a $100 million injection next quarter, when the company is due to make a final investment decision on its Beyondie Potash project in the Pilbara.

And should it hit the green light - as expected - Macquarie Capital will be in its corner helping with the raising.

It comes as Kalium Lakes charges full-steam ahead towards the country's first sulphate of potash production project, which is on track for first production next year.

Fresh from locking in $74 million development funding from the Northern Australia Infrastructure Fund and a $102 million senior project debt package with German KfW IPEX-Bank, Kalium Lakes has inked another milestone in the form of an offtake agreement.

Street Talk can reveal the company has secured a binding 10-year offtake agreement for the full 90,000 tonnes of annual production from its mooted low-cost, long-life potash Beyondie project.

The buyer is German fertiliser giant K+S - which has been in talks with the company and running due diligence for months - and the contract is expected to deliver about $650 million of revenue over the 10-year life of the deal.

Sulphate of potash is a premium fertiliser and is a critical component in the global food supply chain and the K+S deal guarantees that the full production from the Beyondie project is now spoken for.

Kalium Lakes' team has been working with corporate adviser BurnVoir to lock in the financing - and all eyes are now on the mooted equity piece.

Macquarie's research analysts have assumed an $85 million equity raising in their forecasts, along with a $100 million debt facility. The analysts just about hit the debt number on the head with the KfW IPEX-Bank agreement.

It comes as Macquarie's bankers seek to lock in funds for another ASX-listed resources upstart, Aeris Resources. Aeris, with the help of Macquarie and RBC Capital Markets, has its eyes on a $US185 million to $US240 million equity capital raising to help buy the CSA mine from Glencore, as revealed by Street Talk last week.