Copper investors will be keeping close tabs on Indonesia as the government mulls the possibility of imposing a 25 percent export tax, which may go up to 50 percent in 2013, on base metals as well as coal. Indonesia is home to Freeport-McMoRan's (NYSE: FCX) Grasberg mine as well as other key sites of multinational mining groups. Last year, Indonesia exported about $3.8 billion worth of copper.Copper company news Chilean state-owned Codelco announced a senior management shake up this week in an effort to maintain its position as the world's largest copper producer. Julio Aranis will head its North division, which is responsible for the Chuquicamata, Gaby, and Radomiro Tomic mines, the Chuquicamata smelter and refinery, and the Ministro Hales deposit. Codelco's smallest mine, the Salvador mine, was shifted to the Central-South division headed by Jorge Gomez, a former executive of Antofagasta (LSE: ANTO). In addition, two new vice presidencies, one for business development, and the other for technology and innovation, were created. CuDeco (ASX: CDU) signed a structural steelwork supply contract with China's Sinosteel. The contract will allow it to move ahead in developing its Rocklands project in Queensland. Sinosteel will be solely responsible for providing the Australian mining group with the structural steel requirements needed for the entire mineral processing plant. The world's oldest copper mine, at Skouriotissa, has now produced 50,000 tonnes of copper according to Cyprus Mail. The mine is owned by Hellenic Copper Mines and is the sole copper producer in Cyprus. Junior company news Dia Bras Exploration (TSXV: DIB) said its El Gallo mine in Mexico has expanded the boundaries of the current resource. In addition, drilling at El Salto has shown that the Upper and Lower Skarns extend to this area, which is 600 meters east of the current mining area. The latest results “represent a potentially major expansion of the resources of the Bolivar property....We have only just begun to discover the full potential of this extensively-mineralized area, " said President and CEO Daniel Tellechea. Vancouver-based Geologix Explorations (TSX: GIX) began trading on the OTCQX market under the ticker symbol GIXEF. The company's primary focus is the Tepal gold-copper project in Michoacán State, Mexico, where it has completed a preliminary economic assessment study.