TRAIN LINE AND MINES - A PATH OF COPPER

To my father, grandfather and father in law who worked in these mines.

June 1975.
Suddenly I'm with my family and some boxes at the door of the house of my grandfather in Vila Velha de Rodão, Portugal. We were one of thousands of people displaced and pushed of a war triggered to the seizure of power by the armed movements to liberation of Angola. In the beginning were difficult days and comforted me touch on a few minerals has brought from Angola. My grandfather noticing the affection that had to the stones one day gave me a smile with a chalcopyrite specimen. I asked him "grandfather where is from the stone?" And he replied "take the train line to S. Pedro bridge and easily you find the mines.” Past few days I take the Line of Mines…until now!! With minerals from around the world.

1-Introduction
The copper mineralization of Ingadanais mines correspond to main occurrence of copper in Portugal located on north of Tagus River and are integrated in Geopark Naturtejo territory, recognized since 2006 by the integration into European and Global Network of Geoparks, under the auspices of UNESCO, and has a history with more 3000 years of mining activity which was scoring and transforming the landscape. It brings together the municipalities of Castelo Branco, Idanha-a-Nova, Nisa, Oleiros, Proença-a-Nova and Vila Velha de Ródão, with 4617 km2 of territory, away from coast and large urban centers, a geological landscape that tells a story with more than 600 million years.



2-Location
In Castelo Branco District, near and north of Vila Velha de Ródão ville and close to the train line of Beira Baixa there are located some mines with copper explorations and that presently are contained. Their names are as follows:

1- Enxarrique riverside mine.

Location of Ingadanais Mines

Ingadanais Mines, Vila Velha de Rodão, Castelo Branco District, Portugal

2- S. Pedro nº 3 riverside mine.
3- S. Pedro nº 2 riverside mine.
4- S. Pedro-o-Cabeiro mine.
5- Sítio do Cobre mine.
6- Vila Velha de Ródão nº 2 mine.
7- Vila Velha de Ródão mine.
Locally the whole area of these mines is denominated by Ruins of Ingadanais Mines.
The mines nº 1, nº 2 and nº 3 are located on slope along the train line and before of S. Pedro riverside train bridge. Mine nº 1 is located to Km 65.9 of train line. Mine nº 2 is located to Km 66.2 of train line. Mine nº 3 is located to Km 66.7 of train line a few dozen meters from S. Pedro riverside train bridge. The mines nº 4 and nº 5 are located between S. Pedro riverside and Açafal riverside. The mine nº 4 is located to Km 67 of train line and below of S. Pedro riverside train bridge and near the riverside. The mine nº 5 is located to Km 68 and out of train line, near Tostão village, more to NW on the W slope of the Açafal riverside and close of Açafal barrage. The concession area of mine nº 6 is probable located between Km 68 of train line close Tostão village and Km 70 of train line. The concession area of mine nº 7 is located between Km 70 and Km 72 of train line close Tojeirinha village.





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3- Miners work
Works with greater extension and resourcefulness were executed in Enxarrique riverside mine. In this mine has a well which will have reached 143 m of depth and is flooded and stuffed. Near the well exists one dump with well marked stratification, where there are remains of vegetal coal and slag’s. At this location the dismantling was done by the technique of reversed steps. Here occur the foundations of the old machine shop preparation of ore, which is evident by the pool settling in shale, developed on three different levels. The product wash possess 15-18% copper.
S. Pedro riverside nº 3 mine has a well flooded and stuffed. It is verified a dump close the train line.
In S. Pedro riverside nº 2 mine there are two zones that correspond to sub-vertical veins very rusty, verifying works with a dump along the train line, which was partly removed to improving a path.
S. Pedro-o-Cabeiro mine, consists of a gallery extending over 175 m, giving access to two parallel mineralized veins and spaced 38 m. Presently the mouth and the gallery of mine are slaughtered, indicating dumps on slope that are covered by vegetation.
In Sitio do Cobre mine are two wells with galleries / trenches aligned NE-SW, with well nº 1 to 140 m elevation and well nº 2 to 160 m elevation. It is possible to observe in these works, secondary copper minerals resulting from runoff. In well nº 2 there are a quartz vein under which the gallery follows. On the same side there is a dump with brownish yellow color resulting a dismantling of the oxidation level (iron hat) which extends up to the path, that passing below the dump.
In other concessions of Vila Velha de Rodão nº 2 mine and Vila Velha de Rodão mine could not find any traces of exploitation. Proved useless because this area is out of the failure with mineralization.

4-Geology
The mineralized structures are embedded in thin shales, sometimes micaceous, with alternating greywackes belonging to the Beiras Group of Complex shale-greywacke to Ordovician. These mineralization correspond a philoniane epigenetic structures installed in segments of Ponsul failure, a shutdown left and tardy Variscan with complex geometry, reactivated during the Alpine orogeny (DIAS & CABRAL, 1989). The deposit occurs in a network of sub-parallel veins N60 º-70 º E, tilting 80 º to NW. The width of the mineralized quartz veins with pyrite, native copper, chalcopyrite, chalcocite, azurite, malachite and cuprite ranges from 0.5 to 1.4 m, reaching a length of 3 km. In sections of the path connecting the concessions show a supergene alteration of mineralizated vein, particularly in the area of tectonic breccias associated with Ponsul failure. Here there are clear overlaps of pelitic rocks of Beiras Group, with about 600 million years ago, over to formations of Cabeço do Infante rocks, with 50 million to 30 million years.

5-History
The copper Mines of Ingadanais and its mineralization were studied by Guimarães dos Santos (1945) to “Empresa Portuguesa de Estanhos, Lda.” The first records of concessions with works dating from 1904 to S. Pedro-o-Cabeiro mine and Sitio do Cobre mine, which belonged to the French mining company "Société Minière Ibérique", based in Brussels and branch in Vila Velha de Ródão ville, which declared abandoned in 1916 and 1921, respectively.
The other concessions belonged to the French company "Société Anonyme des Mines de Cuivre de Rodan", which came to be located in Gavião de Rodão village until 1921. This firm registered in 1911 the grants of Vila Velha de Rodão nº 2 mine and Vila Velha de Rodão mine. All grants were subsequently awarded to “Empresa Portuguesa de Estanhos, Lda.”. The mining operations ceased in 1968 to S. Pedro-o-Cabeiro mine, Sitio do Cobre mine, Vila Velha de Rodão nº 2 mine and Vila Velha de Rodão mine, 1986 to Enxarrique riverside mine and S. Pedro riverside mines nº 2 and nº 3.

6-Mineralogy
The primary mineralizations of these deposits are catalyzed by the silicium of quartz veins. Are generally constituted by copper, iron, sulfur, arsenic and in lower quantity silver, zinc and lead. Ore base of Ingadanais mines consists in chalcopyrite with quartz and accompanying with pyrite, marcasite, arsenopyrite, covellite and traces of tenantite, galena and pyrrhotite.

















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The secondary mineralization resulting from oxidation of this ore is visualized very well in (iron hat) of Sitio do Cobre mine with changes in other sulphides, oxides, hydroxides and sulfates of copper as well oxides, hydroxides and sulfates of iron.



















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Less common are arsenates and phosphates of copper. The copper of (iron hat) is dislodged by rainwater that will stay in the cementation zone of copper carbonates. The secondary minerals most important are: Copper, chalcocite, cuprite, goethite, malachite, azurite, antlerite, etc. In this deposit is visually identified arsenates and phosphates of copper like clinoclase, olivenite and libethenite. Requires a more detailed study of mineralogy because probably have other representations of sulphates, arsenates and phosphates of iron or copper with other elements. Normally the mineralized fluids drag other elements such as K, Al, Ca, Cl etc. that fit well in the crystalline grids.



7- Slag’s
In Sitio do Cobre mine and along the Açafal riverside near a Roman bridge, there is a slag dump resulting from the smelting of copper ore. These foundry works are prior to registration of the concession in 1904. The slag’s of Ingadanais mines were studied and analyzed by João Carvalho and Miguel Gaspar (2009), which identified another slag dump in Enxarrique riverside mine with works of foundry in fifties. Found that the slag’s from the old foundry of Sitio do Cobre mine are more dense, less vacuolar more devitrified and much more rich in copper when compared with the slag’s of fifties, suggesting a less efficient reduction and that dated this smelting ancient work to the period of Roman occupation in Lusitania.



Roman slag’s present a cover of greenish color due to copper oxidation, are vacuolar with adhesions of shale and vegetal coal. Sometimes exhibit metallic globules inclusions due to the reduction less efficiently. These metallic globules were identified as native copper and cuprite. The globules of native copper, usually bordered by cuprite are common and are frequently modified / decomposed to other metallic phases yet unidentified. Minerals such as cuprite, native copper, covellite, bornite, pyrrhotite and / or cubanite (?), Pentlandite (?), copper sulfates, hematite and goethite tend to fill partially or completely the vacuolar spaces resulting from exhaust gases.



















The copper sulfates normally lodge in the vacuolar spaces along the outer periphery of the slag and was identified brochantite, connellite, antlerite (?).The brochantite presents in prismatic crystals frequently with altered colors to light green, yellow, brown and white, indicating pseudomorphs or series by identifying. Chalcophyllite was identified visually because of the hexagonal crystal structure, analysis effected subsequent to this mineral in Austria by Dr. Uwe Kolitsch indicated 'Unnamed (Cu-S-Si-O-OH)', in all a similar occurrence with slag´s in the locality of Lechnerberg in Austria.
These Roman slag’s explained above also require a more detailed study of Mineralogy, making Sitio do Cobre mine an interesting place in the study of minerals. A brief note about the slag´s of Enxarrique riverside mine, resulting from mining '50s, indicate low density, more vacuolar and vitrified. Present a coating of ferrous oxidation, relics of vitrified rock, vegetal coal, and rarely secondary copper minerals.
How should calculate this article is subject to various interventions update. Any suggestions and if anyone wants to help in building this article with photos or other reference, accepted willingly, in which I will mention to the author.
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Article based on the references cited in Ingadanais Mines.

Martins da Pedra

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