British Columbia-based Lucara Diamond Corp. beat its full-year revenue guidance after taking US$52.9 million in its final diamond tender of 2019, 16% higher than expected.

The December tender brought the company's 2019 revenue to US$192.5 million, exceeding the guidance range of US$170 million to US$180 million.

The company said Dec. 18 that in the year's final tender, it sold diamonds at an average price of US$468 per carat, with 30 diamonds sold for more than US$1 million each.

Meanwhile, the company approved a budget of up to US$53 million for preparatory work at a proposed underground mine at the Karowe diamond operation in Botswana. An investment decision is expected in the second half of 2020.

A feasibility study on the Karowe underground project outlined a posttax net present value of US$388 million, discounted at 5%, with an internal rate of return of 16% and a payback period of 2.4 years.

Lucara's expectation that diamond prices will continue to improve over the next 12 to 24 months "bodes well, not only for our current open pit operations, but also supports our plans for underground expansion to extend Karowe's mine-life to at least 2040, with the potential to generate an additional US$4 billion in revenue," CEO Eira Thomas said.