The funds will be used to develop current projects, acquisition of new projects and for general working capital , it said.
The note carries interest at 3% a year and has the option on or before the maturity date to convert, all or a portion of the unsecured note into units of Tango.
Each unit consists of one share and one share purchase warrant, exercisable for two years, to buy one share for 10 cents each.
Earlier this month, Tango told investors that production had restarted at its Oena diamond mine in the Northern Cape of South Africa.
Contractor Bluedust 7 Proprietary Ltd has mobilized and commissioned mining and processing equipment, including a Bourevestnik X-ray sorter, to the site.