New documents reveal that Colombia was hit with a $16.5 billion arbitration notice last month by a U.S. gold mining company that said its mineral rights were illegally revoked, and an attorney for the company told Law360 Monday that many more claims could soon be filed. Tobie Mining & Energy Inc. and two other companies that planned to dig in the remote Taraira South mining concession told the Colombian government in February that it violated a U.S.-Colombia free trade agreement when it created a national park in the same area that rendered its concession “inoperable,” according to an arbitration notice made public last weekend. Tobie and its Canadian partner Cosigo Resources Ltd. said they spent $11 million to prepare to mine a gold deposit whose value had been pegged at $16.5 billion in geological surveys.