Full year losses more than doubled at UK based explorer Alba Minerals to £1.03m from £442,662 a year earlier, largely due to a £683,000 write-down on the carrying value of the group's exploration projects.The auditors report also raised fears about the firm's ability to continue as a going concern if it fails to raise extra cash.Kalahari Minerals is going well after the miner said results from Rossing South in Namibia suggest the Husab uranium project is part of one of the largest uranium mineral systems in the world.An update from Extract Minerals, of which Kalahari owns 39%, indicates a resource on zone 1 and 2 at Rossing South "well in excess" of 200 million pounds of uranium oxide (U3O8).Platinum Australia has raised A$61.2m from a private placement of 60m shares at $1.02 each, which was oversubscribed, according to managing director John Lewins.Proceeds will be used to retire the Standard Bank debt in regard to the Smokey Hills project in South Africa, crystallize the value in the Smokey Hills hedgebook, develop existing projects, buy and evaluate new projects and for general working capital. Gold producer Minera has identified a strong geophysical chargeability anomaly at its La Falda porphyry gold project in Chile. A Letter of Intent was signed with Catalina Resources in early April in which Minera can earn a 75% position in the project. A full agreement is due at the end of August.Silver explorer Arian Silver posted a pre-tax loss of $481,000 in the quarter to March 31 after deferring all Mexican silver exploration until it receives new funding.