Detailed gold deposit exploration project of Torghabe: The report on detailed exploration of gold (Volume I)
Mohammad Javad Vaezi Pour
Geoscience Development Co
Alireza Babakhani - Fereydoun Kuze-Kannani
following the contract No. 16182 between Overall Exploration Program representative Mohammad Javad Vaezi-Pour and the Geoscience Development Co. representative Mr. Ali Mohammad Joabady at 2000, detailed exploration conducted on the gold deposit of Torghabe. In fact those additional exploration operations include the drilling of exploratory holes, removal of cores and sampling from them, taking a representative sample of deposit for processing tests at semi-industrial scale, and ultimately determination of the probable reserve. Technical and operational teams of the Company travelled to the Torghabe deposit and within three months of drilling and sampling from cores, took the representative samples for processing studies. Totally, 380.35 m exploratory cores in the five holes achieved, 104 samples of core for chemical analysis, 18 samples for studies of polished sections, 6 ore samples for ore-dressing and four samples for thin section studies, harvested and sent to the laboratories. The results of each study are also enclosed. Representative sample of the mineralization zone adjacent to the boreholes BH3 submitted for processing tests that results of it will be presented in a separate report. The results of boreholes and core samples are presented as follows.
The gold deposit of Torghabe includes granite mass, known as Mashhad granite and metamorphic rocks. The metamorphic rocks can be three parts: the remained metamorphic masses in the granite (auriferous unit), metamorphic slate and phyllite in the granite margin or located in the contact between the metamorphic rocks and granite mass and andalusite-garnet schist hosting the granite.
In the mass of granite with different differentiation process from granodiorite, quartz monzonite to granite, there is a significant amount of biotite, tin and tungsten mineralization in a vein phases. The high ratio Al2O3/K2O + Na2O +CaO +Fe2O3 (more than 1 / 1), showes a S type granites. The absolute age of granite is 125 to 146 million years (upper Jurassic-Lower Cretaceous) based on potassium – argon method. Mineralization of gold in the Torghabe has occurred inside metamorphic residual mass within granite that is long and narrow (750 * 450 m). the strip of metamorphic residual mass strongly influenced by the granite-induced heat hydrothermal solutions to show a gneissic-migmatitic appearance. In the polished sections, gold exits in the form of free element in the silica and as inclusion. The gold mineralization associated with a small amount of arsenopyrite in the crushed fault zones. Based on sampling from superficial trenches the gold grade is between 0.1 to more than 23 grams per ton. Based on the semi-detailed study, blocking of ore deposit into 11 blocks estimated 330 kg of gold reserve.