Environmental Engineering Reference
In-Depth Information
Until the eighties the exploitation and processing
of natural stone was performed using manual
processes and the stone was used almost exclu-
sively in religious, civil and military architecture.
since then new extractive methods have been
introduced that allowed to increase production,
to improve the quality and to increase the variety
of products to be used in civil construction, public
works and funerary art. in general, the applications
given over time to the natural stone of the azores
are in accordance with the results obtained in the
physical-mechanical tests being carried out.
The lithological varieties corresponding to the
so-called “pedra de lavoura” and “welded pyro-
clasts” impede any type of polishing due to several
factors: the low hardness of many of their miner-
als, the existence of glass in some stones, the poros-
ity exhibited by others, and the alteration degree as
well as the weak cohesion between minerals shown
in some others.
Despite the existing textural (porosity, size of
the volcanic fragments, and xenoliths) and compo-
sitional differences shown by the studied litholo-
gies, the obtained results are very similar. such
findings are important to assure both quality and
certification of the manufactured products and
the consumer confidence. however, it is recom-
mended the consultation of the harmonized stand-
ards corresponding to the different products to be
manufactured, as well as the periodic control of
raw materials, of products dimension and of the
processing equipments.
The waste from the processing of natural stone
in the azores is almost totally utilizable. in what
concerns the so-called “pedra de lavoura” (hawaiite,
trachybasalt and trachyte) the waste is utilized, either
in the production of pre-fabricated, or sold as the so-
called “lajetas” applied to face walls and pavements,
whereas the waste from the “welded pyroclasts”
(tuff and lapilli tuff) after being ground is utilized
both as soil for greenhouses, and as inert material in
the manufacture of bricks for civil construction.
making available the set of natural stone samples
required to perform the physico-mechanical tests
as well as the petrographic, mineralogical and
chemical analyses.
ReFeRences
costa, l. Rodrigues, leite, M.R. Machado & Moura, a.
casal (1995). o futuro da indústria das Rochas orna-
mentais. Bol. Minas, v. 32, nº. 1, 1-13.
caetano, s.D. (2007). Prospecção de Recursos Minerais:
Modelo integrador de Valores ambientais e de
ordenamento do Território. Tese de Mestrado em
ordenamento de Território e Planeamento ambiental.
Universidade dos açores, Ponta Delgada, Portugal.
caetano, s.D., lima, e.a., Medeiros, s., & nunes, J.c.
(2008). caracterização Geotécnica de agregados natu-
rais dos açores. Xi congresso nacional de Geotecnia,
iV congresso luso-Brasileiro de Geotecnia. coimbra,
Portugal, 8p.
França, Z., cruz, J.V., nunes, J.c., Forjaz, V.h. & Borges,
P. (2003). Geologia dos açores: Uma Perspectiva
actual. Revista açoreana. sociedade afonso chaves.
Ponta Delgada.
Gomes, c.s.F. & silva, J.B.P. (1997). Pedra natural do
arquipélago da Madeira. importância social, cultural
e económica. Madeira Rochas-Divulgações científicas
e culturais, câmara de lobos, 173p.
Francis, P. (1993). Volcanoes: a planetary perspective.
oxford University Press (edition), 443p.
Moura, a. casal (1991). Rochas ornamentais:
características das rochas ornamentais portuguesas e
a importância do seu conhecimento actual. Geonovas,
nº. 2 (especial), 123-136.
Moura
et al
. (1983/4/5 e 1995). catálogo de Rochas
ornamentais Portuguesas. edição instituto Geológico
e Mineiro, lisboa, v. i, ii, iii, iV.
nunes, João c. (2002). novos conceitos em vulcanologia:
erupções, produtos e paisagens vulcânicas. Geonovas,
nº. 16, 5-22.
le Bas, M.J., le Maitre, R.W., streckeisen, a. & Zanettin,
B. (1986)—a chemical classification of volcanic rocks
based on the total alkalis-silica diagram. Journal of
Petrology, v. 27, 3, 745-750.
silva, J., Ferraz, e., Moura, c., Grade, J. & Gomes, c.
(2002). natural stone of the Madeira archipelago:
commercial
types
and
properties.
eurock
2002,
Funchal, Workshop on Volcanic Rocks, 115-124.
silva, J.B.P. & Gomes, c.s.F. (2004). Tipologias de
pedra natural utilizadas no simpósio internacional
de escultura em Pedra (sineP, 2004). câmara
Municipal de câmara de lobos e Madeira Rochas—
Divulgações científicas e culturais, 77-98.
acknoWleDGMenTs
Thanks are due to the enterprises herdeiros de
agostinho Ferreira de Medeiros lda, José Dâmaso
e Filhas lda, and Mário Batista for preparing and
