Nine Indonesian mining firms have resumed export of mineral concentrates, an official said on Tuesday. Bachrul Chairi, Director General of Foreign Trade in the Trade Ministry, said that the firms commenced shipping the mineral products in February soon after they obtained export permits. Bachrul was upbeat on the improvement in the export earning of processed mineral ores, as there would be more mining firms applying for export permits. "As revenue loss is foreseen at 6 billion U.S. dollars this year, the resumption is going to offset it by about 2 billion U.S. dollars," he said. The halt to export of unprocessed minerals from Jan. 12 is partly to blame for 430.6 million U.S. dollars trade deficit in the month, the statistic bureau said. The shipments of mineral ores overseas in January witnessed a steep decline by 70.13 percent to 291.8 million U.S. dollars from a month earlier, it said. On Jan. 12, Indonesia slapped a broad export ban on raw mining products such as nickel, bauxite, tin, chromium, gold and silver as they don't have intermediate products, but still allowed the exports of copper, lead, zinc, iron and manganese till 2017 with the miners being subject to punitive export tax between 25 and 60 percent. Only miners committed to building smelter are allowed to continue exporting mineral concentrates, but they must get export permits. On Feb. 20, Bachrul said that the trade ministry had already approved export permits for the nine firms.