Perucca, Juan Carlos; Cano, Ester; Castro, Graciela; Matar, María
Angélica.Universidad Nacional de San Juan - Av. del Libertador San Martín
1109 (Oeste), SAN JUAN 5400 (Argentina)
San Juan is one
of the three provinces most important producers of marble in Argentina, along
with Cordoba and Buenos Aires. Of this production, can be highlighted travertine
marble for its quality and for being exploited since the end of XIX century,
which has noticed since then a clear preference for the use of ornamental rocks
in public buildings and in the houses of the rich people, both in San Juan as
well as in Mendoza and Cordoba. The deposits are located in a basin with geothermal
activity, used for therapeutical ends in pre-Columbian age, situated about 45
km north of the capital city in La Laja, Department of Albardon.
The distance
to the ports of Atlantic Ocean varies from 1200 to 1800 km, while towards the
Pacific oscillates between 450 and 650 km, crossing the Cordillera de Los Andes.
The region is dry and semi desert, with very dry and scarce water, the temperature
varying from 42º C in summer and -6º in winter, with summer rains
that do not exceed 50 mm annually. The general height oscillates around 750
m above sea level and one some days exceeds 95%.
Physical - Mechanical Characteristics
In San Juan there is a distinction between two types of travertine, dark and
clear, that can be cut along the veins or "to the water" (parallel
to it).
The physic-mechanical tests according to the norms of the European Community,
UNE (Unification of Spanish Norms) and UNI (Unification of Italian Norms), were
realised in the laboratory of Mechanica de Rocas del Instituto de Investigaciones
Mineras, in the Institute Geominero in Madrid (Spain), and in the Dipartimento
di Georisorse e Territorio, of the Politecnico di Turino (Italy).
According to these results one can conclude that the quality of travertine
of San Juan completes with the requirements established for this type of rocks
in the European Union.
ENSAYOS TRAVERTINO CLARO TRAVERTINO OSCURO
TESTS CLEAR TRAVERTINE DARK TRAVERTINE
Porosidad/Porosity (%) 4,02 5,72
Absorción/Absortion (%) 1,65 2,48
Pe aparente/Apparent Pe (%) 2,43 2,30
Pe aparente en H2O / 2,53 2,43
Apparent Pe in H2O
Compresión/Compression (Kg/cm2) 479,45
Compresión T/Compression T (Kg/cm2) 503,91 716,00
Flexión/Flextion (Kg/cm2) 150,00 101,12
Resistencia al choque/ 35 cm 20 cm
Resistance to blows
Resistencia al desgaste/ 40 40
Wear resistance (%)
Dilatación Térmica/ 4,9x10-6 °C 4,7x10-6 °C
Thermic dilatation
Microdureza / Micro-strength 1,63 ----
Methods of exploitation
There are 5 quarries
in San Juan with fronts that vary between 50 and 50 metres length, in banks
of 2 to 12 height.
The traditional method consists of perforation with hand drill realised in
straight lines with space of 4 to 8 cm between drills, and loading one of each
10 with black gunpowder.
Currently, the main quarries operate with diamond cable and chain saws with
teeth of widia, in fronts that go from 4 to 12 m height. The blocks are separated
from the front by means of hydro-pneumatics wedges and received one "bed"
of fine material.
Labour
The quarries functioning normally employ between 6 and 10 workers each, totalling
an average of 30 to 50 people. At the same time, the three plants or saws each
employ 10 to 15 workers, with a total of 30 to 45 permanent workers. (Perucca
et al 1984).
If to these personnel one adds those in transport and other workers in accessory
tasks (administration, truck repair, workshop mechanics, spare parts, etc.)
one can assume that the number of people related to the mining of travertine
marble in San Juan exceed 120.
Uses
In this region (San Juan, Mendoza, San Luis, La Rioja) there exists a clear
tendency towards the use of natural stone in the construction of residential
buildings of medium to high level, in great part helped by the dry climate that
keeps the fronts clean and unaltered. In the rest of the country, the use of
stone is limited to public buildings, banks and monuments, except in certain
touristic centres such as Mar del Plata and Cordoba, where one can appreciate
the particular tastes for granite and quartzite that is extracted in the respective
neighbourhood.
In the city of San Juan there exists a marked preference for the use of travertine
marble in construction of fountains and gardens, both in houses as well as public
buildings. One of the most common applications is, cutting in small blocks applied
in supports by hand finished in general. Another very common form is to install
it in polished slabs as cladding, especially in front of public buildings.
In recent times the use has started, increasingly with greater intensity, of
a combined form of ornamentation of facades integrating the fronts or walls
with diverse materials: various marbles, travertine, limestone or blocks of
sandstone, with polygonal multicolour design. With this system one gets a great
number of variety of forms, type and colour, with striking and exclusive solutions,
a reason that explains its exclusivity.
In a statistical analysis it was observed that in the centre of the capital
city about 53% of family houses have fronts with marble, granites, porphyry,
quartzite and sedimentite of different types. In the commercial centres, banks
and public offices, the use of polished slabs in fronts and staircases reaches
70%.
A very particular use is in monuments in streets and squares, as well as fronts
in historical buildings. In this sense, making use of the ease of working because
of low level of strength and the great number of craftsmen that exist in San
Juan, the soft and clear and very homogenous colour, is also an important attraction,
added to the traditional taste of the people of this region for all artistic
manifestation related to the use of natural elements such as regional stone
and wood.
There is competition generated by other varieties of sedimentary and metamorphic
marbles, almost all produced also in San Juan (Marroquí, Lunel, Bardiglio,
Cipollino, white type Carrara, Ciampo Venato, Andine Black and other diverse
commercial names), apart from the granites proceeding from Cordoba, San Luis,
Buenos Aires and Brazil.
Published on LITOS printed edition. March 2003, no. 65
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Last Updated: July 2008
