METALS, Venezuela Virtual Geology Museum
GOLD
Etymology:
From Latin aurum.
Chemical formula:
Au.
Physical :
- System : Cubic.
- Habit: are rare octahedron-shaped crystals, cubic or dodecahedral, usually presents a very small grains and reports disseminated flakes in a matrix of quartz or rock, forms DC are rare, in common placeresson also compact and round aggregates, known as the nugget.
- Color: Yellow brass, silver-rich gold is paler, while the copper impurity gives a reddish tinge.
- Raya : golden yellow.
- Brightness: cash.
- Hardness: 2.5.
- Density: 19.3.
Description:
Gold with Silver, platinum, etc, are the precious metals group. Gold has had a great influence on the population of some regions, since the news of its existence has always brought thousands of people eager to get rich quickly. As a body of international economic transactions, gold has been expressed on the basis of unit carat pure gold is 24 karat law.
Source:
like Gold Plate, is sometimes found in a pure state. It is extracted from the following sources: in the veins of gold, usually accompanied by quartz, the alluvial gold, and as a byproduct of other manufacturing factories, such as Copper, Tin and Zinc.
Gold is genetically linked acidic intrusions, the most characteristic is the source of hydrothermal quartz veins, which is accompanied by the Pyrite, Arsenopyrite, laGalena, ores gray, Chalcopyrite, the bismutina, the earthquakes. In addition, Gold is found in ore deposits of polymetallic, copper, rare metals, uranium and others, which is extracted simultaneously.
in Venezuela Background:
The discovery of gold in the Venezuelan Guayana is the Brazilian Pedro Joaquin Ayres who in 1824 caught the attention of the inhabitants of the village of Tupequén on the gold content of the sands of Yuruari.
Production began in 1829, but soon interrupted from 1830 to 1856, led to the period of unrest and political turmoil which the country experienced in the early days of his life as an independent nation. Despite all this in 1849, Mr. Pedro Monasterio, Andres Hernandez and others, established the first placer gold in the alluvial sands of Yuruari. Then came a break between 1858 and 1865.
Location
The first deposits Venezuela Gold mineralization is associated with a hypothermic type Au-Fe-W that affected much of the central region of the Guayana Shield, mainly pastoral groups and training him to Callao. Because of the vastness of this metallogenic zone, secondary deposits of gold in alluvial deposits and eluviones are abundant throughout the eastern and central regions of the Guayana Shield.
Of the primary gold mineralized regions, the El Callao looms large. This region has been the center of gold production since the colonial era in the eighteenth century. In the ring gold of El Callao, have been exploited over 230 quartz veins, auriferous pyrite and native gold.
Geologically, the deposits are mainly associated with the lavas of the Callao Training and the Training Caballape and even with metagabbro, but the veins embedded in the lavas are the most popular and extensive and higher production.
existing reservoirs in regions close to rivers and Cuyuní Yuruari and the Botanamo River, consist of quartz veins and gold-bearing reefs of the type of filling cracks. In general, show dips slopes with runs of about 200 m (although some spend 1 km), average thickness of 60 cm and a vertical extent of 200 - 400 m.
The mineralization of the veins and lodes are simple and consist mainly of quartz, gold and pyrite, although some mines are small amounts of tetrahedrite, chalcopyrite, bornite and Scheelite. Are typical mesothermal deposits.
The cause of the mineralization in the Guayana Shield has been an unexposed granitic magma. Several deeper mineralized zones have been noted acidic intrusive rocks or at least shown them. In the region of El Callao, mines Laguna, Remington, and Old Callao, have been observed depth aplite dikes that suggest a granitic magma. In addition to the aplites, has established the presence of granites and diorites in nearby areas.
Tectonically, the most important repositories of the region are located along shear zones, as in El Callao, or in areas of gaps caused by faulting of the veins as in the case of Botanamo, Vuelvan Caras, Bochinche, Save the Fatherland and Introduction. In Botanamo mines, Vuelvan Caras y La Estrella, was took in a system of primary fractures, accounting for directions to the shale host rocks, which appear to determine the course of the veins. Another system was also observed after the first fracture, accounting for the failures that led to the breccia zones. This system is more complex fractures in the region of El Callao, where it has been observed no additional deformations.
Due to the large geographical extent of the primary hydrothermal gold deposits in the eastern state of Bolivar, whole region has many eluvional Gold concentrations in ancient and modern avenues, terraces and eluviones of different ages and geomorphological features. The most productive areas are associated with the drainage of rivers Yuruari, Cuyuni Botanamo, Corum, Gurampín, Matupa, Hondo, Grande, Oronato, Carichapo, Macarumo and Supamo.
Application:
is mainly used as a basis for monetary sitema and as a means of payment in international trade. From the earliest times has been used in the manufacture of jewelry and ornaments and coins. It is also used for professional, artistic and industrial, such as: jewelry, making X-rays, radiation, sound transmitting apparatus, photographic equipment, the manufacture of armaments, dentures, etc..
Associations:
is the principal ore of gold, with regard to Native Gold deposits, Gold minerals other scarce and rare, and pyrite (S2Fe) , tetrahedrite, argentite (SAG2) and gold galleries, far behind. The sites are rapidly depleted by the eagerness and intensity with which they are operated, and so happen to be poor in countries with ancient gold civilization.
Most farms gold Gold has been the state of free metal finely divided. Certain amount of gold found in the sulphides, pyrite and Mispiquel, in solid solution, especially in some hydrothermal veins extrusive.
and market statistics:
As gold ore, the Corporacion Venezolana de Guayana (CVG) estimated a total investment of approximately 1.7 billion dollars to 1998.
CVG estimates indicate that in Bolivar state, there are approximately 5 000 metric tons of gold that can be exploited in the area and other 3 000 by underground mining.
Its production recorded 3.5 tons (MEM) in 1988 and Goldfields estimated 20 tons in the same year, official registration in 1992 up to 8.5 tonnes and 11.7 were estimated according to other international sources , then in 1994 there were 10 tonnes, against 13.7 were estimated by unofficial sources. For 1999, the estimated amount was close to 15 tons.
References :
BALESTRINI, C. (1959) Mining and Petroleum Economics, Caracas. Universidad Central de Venezuela.366 p.
CAMIVEN: 1999 WAS A BAD YEAR FOR THE MINING INDUSTRY. Economy Today, Caracas (Venezuela), 01/24/1900.
GOLD, GG & J. JUBANY CASANOVAS. Atlas of mineralogy. sl, Stock ATLAS OF SCIENCE, EDIBOOK, SA, 94 p.
KLOCKMANN, F. & Ramdohr, P. (1955). Treaty of Mineralogy, Barcelona. Edit. Gustavo Gili SA 716 p.
MILOVSKI, AV & OV Kononov. (1952). Mineralogy, Moscow. MIR. 319 p.
MINISTRY OF MINES AND OIL, GENERAL MANAGEMENT (1963).
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