Viridis Mining and Minerals (ASX:VMM) completed the definitive feasibility study (DFS) for its Colossus rare earth project in Brazil, returning a pre-tax net present value (NPV) of $1.87 billion and an after-tax NPV of $1.2 billion at an 8% discount rate, with an after-tax internal rate of return (IRR) of 36.4%, according to a Thursday Australian bourse filing.

The company said the project has a capital cost to first production of $405 million excluding contingency, a payback period of 2.7 years after tax, and total revenue of $8.54 billion over a 25-year production target, the filing added.

The company's shares fell 2% in recent Thursday trade.