Cheliax is pretty sure it can find a million gold pieces in actual gold to redeem money owable to the Project, without that doing anything strange to their economy. If it's more than that, they want to be able to repay him in other valuables that Keltham approves, with a fallback to a guarantee to pay in standard valuables that would be available to somebody requesting to redeem currency at the Chelish central bank. At the same value in those valuables per face-value gold-piece instrument as would have existed at the time of signing this contract, if Keltham is worried about currency devaluation.
Keltham adds a note that the key date will actually be a day before Keltham's arrival, so they can't just drop all those valuations by a factor of 100 for one minute while signing the contract, but otherwise sure. Also just to be sure, can somebody give him three examples of standard redeemables and prices as they were on that day?