Gold Deposits in Chile

A review of gold and gold bearing base metals deposits in Chile, indicate the existence of at least six different type of ore deposits, most largely formed during the Cenozoic with predominance in the Miocene. Mesozoic deposits are common but less relevant regarding their size and gold content. These hydrothermal ore deposits are genetically associated with subduction related Andean arc magmatism. Due to its relationship with episodic magmatism migrating eastward, there is a tendency for the deposits to be in distinct, north-south trending, belts with a progressive west to east decrease in mineralization age. After analysing 82 cases in total, main gold concentration can be assigned to high-sulfidation epithermal and porphyry type deposits. Low-sulfidation epithermal, IOCG and mesothermal type appears as less relevant. Gold bearing copper deposits constitute an important part of Chile’s total gold production. Both IOCG type but especially porphyry copper deposits are and will remain as a substantial source to supplement the future output of the gold in the country. The 82 deposits with their tonnage and grade studied, represent a total gold content of 11,662 t equivalent to 375 Moz, excluding past production for those exploited. A number of probable gold bearing base metals high tonnage deposits (IOCG and porphyry copper) do not include their gold content in public format, hence the number delivered could be estimated conservative. Methodical geochronological, ore types and zonation studies are required to better appreciate this metallogenic setting widening current understanding and future exploration results.

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Geochronology of the porphyry copper deposits and related mineralization of Mexico

Canadian Journal of Earth Sciences ◽

10.1139/e83-095 ◽

1983 ◽

Vol 20 (6) ◽

pp. 1052-1071 ◽

Cited By ~ 60

Author(s):

Paul E. Damon ◽

Muhammad Shafiqullah ◽

Kenneth F. Clark

Keyword(s):

Porphyry Copper ◽

Volcanic Rocks ◽

Basin And Range ◽

Ore Deposits ◽

Porphyry Copper Deposits ◽

Volcanic Arc ◽

Copper Deposits ◽

Plate Convergence ◽

The North ◽

Narrow Belt

K–Ar dating demonstrates that all but eight of 41 dated porphyry copper and related ore deposits of Mexico were emplaced during the Laramide episode of maximum plate convergence. One older deposit is related to the Jurassic volcanic arc of western North America, one is pre-Laramide Cretaceous, four are Oligocene in age, and two late Cenozoic deposits are within the modern trans-Mexican–Chiapenecan volcanic arc. Thirty-three of the deposits lie within a long narrow belt that continues into Arizona and New Mexico, and widens from 100 km to over 300 km in the region of maximum extension in the southern Basin and Range Province. Eighty-five percent of the deposits were emplaced during the eastward transgression of the Cordilleran volcanic arc in middle Cretaceous through Eocene time.The occurrence of the porphyry copper deposits of Mexico appears to be independent of the terrane intruded and the copper content of the wall rocks where the wall rocks predate the volcanic arc, which is syngenetic with the porphyry stock. However, strontium is significantly more radiogenic where the host porphyry has intruded terrane having a Precambrian crystalline basement. Most frequently, the porphyry pluton can be observed to have intruded penecontemporaneous volcanic rocks or the batholith itself. The porphyries appear to be apophyses of the batholiths. The relationships suggest that the ore components are contained within the calc-alkaline batholiths and concentrated in the subvolcanic porphyries and wall rocks during transport of hydrothermal fluids to the volcanic orifice.The shape of the Cordilleran copper belt is controlled by magma composition, existence of a protective capping of dominantly volcanic rock, uplift, time, and erosion. As the continental volcanic arc that produced the porphyry copper deposits progressed eastward, the associated magma became more alkalic and copper poor. Thus, enrichment to ore grade became increasingly improbable to the east. Uplift and ample time for erosion prior to the return of the continental volcanic arc reduced the probability of ore preservation to the west. Optimum conditions for preservation were present within the belt where burial of calc-alkalic porphyry plutons under a thick volcanic cover occurred before removal of the ore zone by erosion. The broader width of the porphyry belt to the north is probably the result of both more extensive basin-and-range extension and basin-and-range taphrogeny that exposed some of the porphyries to relatively recent denudation and consequently made them available for economic exploitation.

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Geological and mining features of gold deposits development of Ryabinovoe gold deposit

RUDN Journal of Engineering Researches ◽

10.22363/2312-8143-2020-21-2-113-122 ◽

2020 ◽

Vol 21 (2) ◽

pp. 113-122

Author(s):

Sergey V. Ryzhov ◽

Marina V. Rylnikova ◽

Ekaterina N. Esina

Keyword(s):

Gold Deposit ◽

Complex Structure ◽

Mining Industry ◽

Production Capacity ◽

Integrated Approach ◽

Gold Deposits ◽

Ore Deposits ◽

Production Volume ◽

Gold Content ◽

Gold Bearing

The significant role of the gold mining industry in the development of the Russian mineral resource system determines the search for new organizational, technical and geotechnical solutions to improve the completeness and efficiency of deposit development. Most of Russia's gold deposits are in remote, sparsely populated areas, where there is a lack of energy, transport communications, and infrastructure. It is shown that the Ryabinovoe gold deposit, located in the Republic of Sakha (Yakutia), is characterized by a complex structure, relatively low occurrence of ore deposits and a widespread in the value of mineral raw materials. Features of the Ryabinovoe deposit consist in a complex structural structure and alternation of mineralized gold-bearing and low-gold-bearing or ore-free areas of various capacities and complex morphology. The main criteria for open Geotechnology have been clarified and justified. This ensures safe and efficient development of the Ryabinovoe field with the achievement of the maximum possible total discounted income and the shortest recoupment period for the project. In general, an integrated approach is the basis of the development strategy of the Ryabinovoe gold deposit. It includes increasing the level of extraction of useful components, increasing the production volume and a differentiated approach to the choice of a method for processing ores of different quality. It is shown that the achievement of rational production capacity in the complex development of the Ryabinovoe gold deposit is based on optimizing the variation of the onboard and average gold content with justification of the ratio of production capacity of the mining and processing cycle.

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