Trace Element Geochemistry of Chalcopyrites and Pyrites from Golpu and Nambonga North Porphyry Cu-Au Deposits, Wafi-Golpu Mineral District, Papua New Guinea

Studying elemental geochemistry of hypogene sulphides can discriminate the hydrothermal fluids responsible for ore formation. To determine whether Golpu porphyry Cu-Au deposits are related to the Nambonga North porphyry system which is located 2.5 km apart in the Wafi-Golpu Mineral District, Papua New Guinea, we compare the trace element compositions of drill core chalcopyrites and pyrites analysed using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS). The results for the Golpu chalcopyrites revealed high concentrations of Au, As, Se, Mo, Sb, Te and Bi and lower concentrations of Ag and Zn compared to those from Nambonga. Pd and Pt were below the detection limit in chalcopyrites for both deposits. The results for the Golpu pyrites indicated high concentrations of Pt, Au, Se, Mo, Sb, and Te and lower concentrations of Cu, Zn, As, Ag, Pb, Pd and Bi compared to those from Nambonga North. Au concentrations in the pyrites from both the porphyry deposits were higher compared to chalcopyrites, which mean that pyrite is the Au-bearing sulphide responsible for the higher Au content. In contrast, Cu values in pyrites from Nambonga North are higher than those from Golpu. Overall, it is envisaged that the ore fluids were exsolved at different times during the evolution of both porphyry deposits, although these porphyry centres may be related in space and time.

Studi Perbandingan Kadar Ni dan Fe Berdasarkan Sampel Cek Pit dan Sampel Cek Stock Pile Mining Nikel pada PT. Bintangdelapan Mineral Sulawesi Tengah

Nickel mining in PT. Bintangdelapan Mineral District located in the village Fatufia Bahodopi Morowali, Central Sulawesi. The purpose of this research study sampling techniques and sample checks pit stock pile, and aimed to compare the levels of Ni, Fe. The authors limit the issues on comparative levels of Ni, Fe, based on sampling and sample checks pit mining production and production sample port stock pile, using the analysis tool Minipal. Field research methods consisting of the preparation stage, the stage of data collection, data processing stage and phase of Thesis. Results in getting the checks on the sampling pit, mining samples, and sample port is an increase in levels, this is because the mining PT. Bintangdelapan Minerals has applied to both selective mining mining methods. In this sample, the researcher applied sampling method and sample check stock pile pit nickel laterite operations in accordance with standard PT. Bintangdelapan Minerals, the data obtained is processed using Microsoft Excel and then presented in the form of reading SPSS (Statistical Product And Service Solution).

Mineralization constraints on the origin of polymetallic (Pb, Ag, Zn, Cu, Au) deposits hosted in the metasedimentary Lajeado Group, Southern Ribeira Belt, Brazil

The sediment-hosted polymetallic (Pb, Zn, Ag, Au-Cu) mineralization of the Vale do Ribeira Mineral District has been known since the beginning of the 20th century, but exploration was interrupted just before the turn of the century. The Vale do Ribeira Mineral District is part of the Southern Ribeira Belt, developed during the Brasiliano-Pan African orogeny. Polymetallic mineralization is mainly hosted in metalimestones of the Lajeado Group, a typical platform carbonate sequence of a passive margin, which has been deformed during the Gondwana assembly. The region has a gap of research since the mines were closed, which justifies new projects on their mineral economic potential. Fieldwork, petrographic and geochemical analyses were developed in five currently inactive mines (Panelas, Barrinha, Rocha, Lajeado, and Furnas) and their surroundings, along with the description of a drill core executed in the 1980s. The main type of ore consists of polymetallic fault-fill veins of massive sulfide, which are composed essentially by argentiferous galena, sphalerite, pyrrhotite, arsenopyrite, and chalcopyrite. The highest ore grades were obtained from samples in the Panelas Mine, with contents of up to 35% lead, 5% zinc, > 1% copper and 564 ppm silver, as well as 23% iron. New ore occurrences were described in a secondary gallery of the Barrinha Mine, whose gold grades reached up to 5,630 ppb. The main controls of the mineralization are lithological - since the ore occurs exclusively in carbonate rocks, irrespective of the geological unit - and structural, related to NE high-angle strike-slip fault zones, including evidence of fault-valve behavior. Fault zones as the main control of the polymetallic veins is an innovative interpretation, increasing the perspectives for mineral exploration in the area. Although they are small deposits, the presented data indicate that the region has potential for new discoveries and that the mined deposits are probably not exhausted.