Early in 2004, Rio Tinto and Rio Tinto Zimbabwe approved expenditure of US$11 million on a small scale plant to start diamond production at Murowa near Zvishavane in southern Zimbabwe. An updated feasibility study confirmed the existence of three kimberlite pipes representing a mining reserve of 18.7 million tonnes of ore at a grade of 0.9 carats per tonne. Commercial production commenced in the third quarter. Diamonds from Murowa are marketed through Rio Tinto Diamonds in Antwerp. Safeguards are in place regarding the chain of custody of the product. Zimbabwe is a signatory of the Kimberley Process.