Luanda, Angola, 27 April – The 1st Angolan International Mining Fair (FIMA) is due to open Thursday in Luanda with the presence of 115 companies linked to the mining industry, especially those from the diamond sector.
Amongst the exhibitors, who will take up two pavilions at the Luanda International Fair (FILDA), on the outskirts of the Angolan capital, are several foreign companies from Portugal, South Africa, Zimbabwe, Egypt, Namibia, India, Canada, Argentina, Zambia, Israel, Italy and Brazil.
The fair, which will be held until Sunday, will also involve Angolan companies representing every province in the country with mining activities.
Research, production, sales, equipment manufacturing and support services companies are all taking part in the fair, which aims to cover all sub-sectors of this area of activity, from diamonds to ornamental stone, as well as precious and semi-precious stones, base metals, and mineral industries.
As part of the fair, seminars will be held to analyze issues related to mining in Angola, including legislation regulating investment in the country.
Angola is recognized as having particularly rich and varied mining resources and it is estimated that it harbors 35 of the 45 most important minerals for world trade, including oil, natural gas, diamonds and phosphates, as well as iron, gold and ornamental stone, amongst others.
Despite this variety Angola’s mining industry has been restricted, since its independence, to oil, diamonds and on a smaller scale
marble and granite.
FIMA has been organized by EXPOANGOLA, a company specialized in organizing fairs, and state diamond company Empresa Nacional de Diamantes de Angola (ENDIAMA), with the support of the Ministry of Geology and Mines. (macauhub)
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 | | Marble | MARBLE: CHARACTERISTICS
This standard includes general information on the characteristics
and common uses of marble and identifies typical problems
associated with the material.
INTRODUCTION
Marble is an extremely hard, metamorphic stone composed of calcite
(CaCO3). It is formed as a result of the recrystallization of
limestone under the intense pressure and heat of geologic
processes. The effect of this process is the creation of a stone
with a very tight crystalline structure and small but definite
porosity. Because of its structure, marble can take a very high
polish and is a very popular decorative stone for architectural and
sculptural uses. The limited porosity of marble, especially
polished marble, makes it less vulnerable to the leaching effects
of water. Calcium carbonate, however, of which marble is composed,
is highly susceptible to attack by acidic agents. Marble is
readily dissolved by acids, even very dilute acids, however the
actual results of acidic exposure will vary with the nature of the
acid. Chlorides, nitrates, sulfates and other chemical compounds
react differently with marble and produce various by-products,
which have a wide range of solubility and impact on the durability
of marble. For this reason, it is always important to determine
the exact type of pollutants causing marble deterioration.
Marble itself can be of two types, one composed of calcite and the
other of dolomite. Dolomitic marble is much more resistant to acid
attack than calcite marble. The color of marble ranges from the
brilliant white of calcite to black, including blue-gray, red,
yellow and green, depending upon the mineral composition.
TYPICAL USES
Marble has many decorative and structural uses. It is used for
outdoor sculpture as well as for sculpture bases; in architecture
it is used in exterior walls and veneers, flooring, decorative
features, stairways and walkways. The way in which the stone is
used may be a factor in limiting or controlling the severity of
exposure. The use or function of the marble may also affect the
feasibility of applying certain treatments, but type of use is not
the primary factor in the major types of deterioration and damage
to which marble is susceptible. | |  |
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Linear Mode
