Tenke advances Alto Rico (March 24, 2003)

Vancouver — Tenke Mining (TNK-T) has tabled encouraging early results from its geophysical program at the low-sulphidation epithermal gold-silver prospect known as Alto Rico, in the Argentine portion of Patagonia.

Crews outlined large coincident geophysical and geochemical anomalies at the 43-sq.-km property following induced-polarization and resistivity surveys totalling 62 line km. Resistor and chargeability anomalies span an area measuring 3 by 1 km, and they lie along trend with the main vein and stockwork zone. In addition, Tenke has dug and sampled 40 trenches totalling 2,500 metres.

Assay values range from 0.35 to 4.5 grams gold per tonne in veins and up to 2 grams gold in stockwork. Mercury anomalies range from 5,400 to 26,500 parts per billion, whereas arsenic ranges from 180 to 951 parts per million and antimony ranges from 29 to 117 parts per billion.

Mineralization exhibits banded textures with open-space fillings. Other features, such as bladed calcite replaced by quartz, suggest conditions near the top of an epithermal system above the boiling zone — a level at which pressure and temperature conditions favour precious metal precipitation.

The Alto Rico vein system has been traced for more than 12 km. It consists of five principal sub-parallel veins that trend to the northeast. The veins vary between 1 and 10 metres in width and have an average outcrop width of 3 metres. They converge on a hill that shows signs of extensive stockwork, silicification, acid leaching and argillic alteration.

Mineralization is hosted in permeable dacitic-to-andesitic tuffaceous rocks. Fieldwork is expected to be completed by early April, and drilling is anticipated by the end of that month.

Meanwhile, 30 km to the northwest, Tenke is working on a similar prospect, El Macanudo, which is part of the overall Alto Rico project. El Macanudo hosts a thick (up to 40 metres) and extensive (at least 4 sq. km.) sinter sequence hosted in volcanic tuffs and ignimbrites.

Sinters represent indicators of low-temperature silica precipitation above active epithermal systems that may have the potential to host precious metal deposits. The area hosts strong mercury, arsenic, manganese and calcium anomalies, which are being sampled. Initial geophysical surveys (induced-polarization and resistivity) indicate a possible feeder structure below the sinter.