New data regarding the resources of tellurium and its distribution in the waste dumps and tailing dam from the Certej-Sacaramb ore deposit, Metaliferi Mts., Romania

The Sacaramb ore deposit is located in the so-called ‘Golden Quadrangle’ area situated in the Metaliferi Mts. and it is the most important Au-Ag tellurides deposit in Romania and in Europe, too. Genetically, it is a hydrothermal vein deposit with Au-Ag tellurides. The ore veins are located in an andesitic stock (pyroxene andesite of Sacaramb) generated by the Neogene calc-alkaline magmatism in the Metaliferi Mts. The vertical extension is about 600 m and the surface of this stock is ca. 1 km². Over 100 mineral species have been identified in the Sacaramb ore deposit, some of them firstly described in the world (nagyagite, petzite, krennerite, stuetzite, muthmannite, museumite). Till recently, tellurium was interesting only from scientific–mineralogical point of view and there was no interest for resource estimation in Romania. Since 2005 this element started to be considered as an important one, when the company “First Solar”, USA used it in the construction of solar panels with photovoltaic cells based on Cd-Te technology.
   The first estimation regarding tellurium resource of the Sacaramb ore deposit was made by Udubaşa & Udubaşa (2004), taking into consideration Au/Te ratio, (i.e 1/2) into the most common tellurides - nagyagite and sylvanite (1/2 ratio) and the amount of gold extracted from Sacaramb ore deposit (over 1746-1941), calculated as being ~ 30 t Au. Therefore, the amount of Te mined and unprocessed (i.e. just dumped) would be ~ 60 t.
   Our report presents the results of the last two-year research on the tellurium resources hosted into three waste dumps (Sectors I, II and III – at Sacaramb area) and into the “Iazul Avariat/Damaged Tailings Dam” at Certej. The tellurium contents have been determined using ICP-MS on the previously analyzed samples where Au-AA26 method for Au- and Agcontents was made. Based on the resulting data the Au/Te ratio was obtained and the tellurium resources were estimated. Concerning the Au/Te ratio, it should be mentioned that this is ~ 0.25 in the case of the damaged tailing dam and it is averaging 0.35 in the three waste dumps; these values are different from the above mentioned theoretical values. The explanation of the existence of a higher Au/Te ratio in the damaged tailing dam is that the tailings originate from the processing plant where gold has been recovered, but tellurium has not. Consequently, the Au/Te ratio changes for Te. There is a difference in the content of useful elements in all four investigated zones, meaning that the waste dumps have higher Au and Te contents in comparison with the ore deposit. According to the new data, accepting that the Au/Te ratio is 0.3, it would result in a resource of ~ 85.7 t of tellurium for all the perimeters of Sacaramb.
   Regarding the correlation degree, tellurium is directly well correlated with gold and silver respectivelly, confirming that tellurium is related to gold and silver mineral compounds. Actually, the Au, Ag and Te distribution map into the tailings dam area and waste dumps area indicates an overlap of the enrichment zones for all these elements.
   Acknowledgements: This work is part of a research project funded by the Ministry of Education and Research. Many thanks to Deva Gold SA, for the support provided in the field research programme.