The Industrial Development Corporation of South Africa is providing 100 million rand (US$7 million), as first announced in October.
Commercial diamond recoveries from Mothae started earlier this month via the new 1.1 million tonne per annum plant.
The plant includes advanced diamond recovery technology including two XRT modules designed to recover large and rare Type IIa diamonds ahead of the secondary crushing circuits to avoid breakage.
The project is a 70:30 joint venture between Lucapa (as operator) and the Lesotho government.
The JV has received proceeds of around $1.5 million from the sale of roughly 4000 carats produced via bulk sampling.
The sale included prices of up to $15,000 per carat for individual diamonds.
Earlier this month a 78 carat white diamond was recovered, the largest so far.
The first sale of commercial diamonds is expected in the March quarter.
Shares in Lucapa (ASX: LOM) fell half a cent yesterday to A18.5c, valuing the company at $86.4 million.