抄録
The Atacama Kozan Mine is located in the Candelaria-Punta del Cobre district which is known to host IOCG type ore deposits. The ore deposit of the mine lies at 300m-400m below the surface and it is completely a concealed ore deposit.
The Nittetsu Mining Co., Ltd. has conducted exploration work in the area consisting of surface geological surveys, geophysical surveys and drilling surveys in order to develop the Atacama Kozan Mine.
In the early days of the exploration the ore deposit type to be expected in this area was thought to be of breccia (vein) type from the analogy to the deposits of the Socavon Rampa Mine and the Carola Mine just across to the east of the valley. But as the drilling survery went on, frequent occurrences of layered copper ore accompanying abundant, magnetite were recognized from a certain horizon of the strata and a horizontally elongated shape of the ore body was implied by subsequent geophysical surveys such as CSAMT, TDEM, and PEM logging survey. So the target ore deposit type was modified to the one composed of strata-bound (manto) ore deposit although it was still in an early stage of the exploration.
Based on this ore deposit model, an exploration tunnel was excavated and drilling surveys were conducted both from the surface and the underground. Consequently an ore reserve of 30 million tons (with the recoverable ore of 20 million tons) at the copper grade of 1.5% was discovered and finally the Atacama Kozan Mine was developed.
