Volcanogenic Gold in the Massive Sulfide Environment

Author(s):  
M. D. Hannington ◽  
K. H. Poulsen ◽  
J. F. H. Thompson ◽  
R. H. Sillitoe
Keyword(s):  
1976 ◽  
Author(s):  
J. S. Stacey ◽  
B.R. Doe ◽  
L.T. Silver ◽  
R.E. Zartman

Geophysics ◽  
2001 ◽  
Vol 66 (1) ◽  
pp. 70-77 ◽  
Author(s):  
B. B. Bhattacharya ◽  
Dinesh Gupta ◽  
Buddhadeb Banerjee ◽  
Shalivahan

A mise‐a‐la‐masse survey was carried out in Bhukia area, Banswara district, Rajasthan, India for auriferous sulfide occurrences. This area was originally surveyed for copper mineralization. Exploratory drilling, however, proved it to be economically not viable. The area was reopened for geophysical surveys when grab samples indicated the presence of gold. Initial geophysical surveys for copper mineralization showed electromagnetic, induced polarization, and resistivity anomalies. At first, one borehole was drilled for gold exploration on the basis of initial geophysical surveys. It encountered massive sulfide mineralization in association with gold. Borehole logging and a mise‐a‐la‐masse survey were carried out in this borehole. Three further boreholes drilled on the basis of the mise‐a‐la‐masse results encountered massive sulfide mineralization in association with gold. One of the three boreholes, 100 m from the first borehole along strike, was used for another set of mise‐a‐la‐masse measurements. A composite equipotential map was prepared using the results of mise‐a‐la‐masse results of both the boreholes. The equipotential contours show a north‐northwest‐south‐southeast trend of mineralization. The boreholes drilled on the basis of the mise‐a‐la‐masse results have delineated a strike length of more than 500 m of gold‐bearing sulfide mineralization. The sulfide content ranges from 10 to 40% and gold concentration ranges from 2 to 6 ppm. The dip and plunge of the lode, as anticipated from the mise‐a‐la‐masse results, are toward the west and north, respectively. Mise‐a‐la‐masse surveys are continuing in the adjoining areas.


Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 85
Author(s):  
Mónica Arias ◽  
Pablo Nuñez ◽  
Daniel Arias ◽  
Pablo Gumiel ◽  
Cesar Castañón ◽  
...  

The Touro volcanogenic massive sulfide (VMS) deposit is located in the NW of the Iberian Variscan massif in the Galicia-Trás-os-Montes Zone, an amalgamation of several allochthonous terrains. The Órdenes complex is the most extensive of the allochthone complexes, and amphibolites and paragneisses host the deposit, characterized as being massive or semimassive (stringers) sulfides, mostly made up of pyrrhotite and chalcopyrite. The total resources are 103 Mt, containing 0.41% copper. A 3D model of the different orebodies and host rocks was generated using data from 1090 drill core logs. The model revealed that the structure of the area is a N–S-trending antiform. The orebodies crop out in the limbs and in the hinge zone. The mineralized structures are mostly tabular, up to 100 m in thickness and subhorizontal. Based on the petrography, geochemistry and the 3D model, the Touro deposit is classified as a VMS of the mafic-siliciclastic type formed in an Ordovician back-arc setting, which was buried and metamorphosed in Middle Devonian.


Author(s):  
Tetsuo Yamazaki ◽  
Yosuke Takeda ◽  
Rei Arai ◽  
Naoki Nakatani

Because of the higher Au, Ag, and Cu contents, seafloor massive sulfides (SMS) have received much attention as future commercial mining targets by private companies and nations. One of them, Solwara 1 Project in Papua New Guinea (PNG), is scheduled to start the commercial mining operation from 2018. Because the mining site is inter-island area and almost no cost is necessary for the waste disposal in PNG, the economy of the mining is expected very well. In contrast with this, because all the SMS distribution sites in Japan locate outer ocean areas and the waste disposal cost on land in Japan is very expensive, the economy of SMS mining in Japan is quite negative. In order to overcome the problems, a self-standing riser with flexible link to the sea surface platform and a primary ore separation on the seafloor prior to the ore lift-up are proposed. The improved SMS mining concept named Japan’s model is examined.


2004 ◽  
Vol 21 (2) ◽  
pp. 77-85
Author(s):  
O. A. Orumwense ◽  
T. Negeri ◽  
R. Lastra

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