The copper mine of Herdade da Mostardeira
Last Updated: 19th Jan 2013
The copper mine of Herdade da Mostardeira, a few notes of its story
The mine of Herdade da Mostardeira, probably discovered by the Romans, exploited existent copper ores in quartz veins, formed in post-tectonic faults.
Granted in August 1862, it had a short productive life, because it scarcity in ores, it low content in copper and a lack of suitable technology. At the time, there were major copper mines offering serious competition by the same markets, also.
One century over its closing, it still remains major traces of great activity, denounced by ore and scoria wastes and by the old shafts and main buildings. From the whole, it stand out the old chimney of the roasting plant, majestic memory, built in stone, raised indifferent to the times and weather (*)
The Mostardeira Mine is included in a large number of small copper mines associated to lode structures dispersed throughout the country, which had its biggest development in the second half of the twentieth century. Its mining operations which was sporadic due to the limited reserves was induced in the Southern Portugal by the strong mining activity developed around large masses of sulphides in the Iberian Pyrite Belt. Some of these world-class deposits have been exploited by the Romans who extracted Cu, Ag and Au from their gossan outcrops.
Some of these small mines such as the long abandoned Mostardeira, still materialize the memory of the copper "booming" that occurred in the second half of the last century and witnessed the days when the steam engine was a symbol of modernity and the journeys of 10 hours inside the galleries depended on the faint light of oil lamps.
Mostardeira scorodite, a relatively common secondary mineral resulting from the oxidation of arsenopyrite
The Mostardeira Mine area is in the Sousel-Barrancos band integrated in the Estremoz-Barrancos sector of the Ossa-Morena Zone.
Overlooking the Campo Vale de Rei and situated about 4.5 km SSE of Estremoz, the Mostardeira Mine explored the copper mineralization. The ore occurs in quartz veins associated with carbonates (siderite) and is composed by pyrite, chalcopyrite, arsenopyrite, native copper, tenantite / tetraedrite and a rare blend. At the top of the structure it is observed secondary copper minerals such as malachite, cuprite and chalcanthite accompanied by hematite.
Although the discovery rights have been requested by José Rodrigues Torcha who saw his request recognized by royal decree of 25 February 1861, the Mostardeira had already been the target of works in “ancient times” as reports by the mine inspector João Ferreira Braga in 1861.
There are now ample evidences that the copper mining in Portugal dates back to pre-Roman period, however it seems to have been this people who gave the greatest incrementation along with many testimonies of their activity in the Ossa-Morena Zone.
Although elements of the economic evaluation of the mine are confined practically to prospecting and research conducted by R. Torch in old wells, J. F. Braga did not hesitate, to propose the progress of the works, convinced of their potential interest. The lodes were dismantled by the system of reversed steps with the subsequent filling of the voids. In the area of the Glória well the lode reached a width of 4.5 m.
Only in the mining plan submitted in 1862 by B. Guerreiro whom was the first responsible person for the mine it was foreseen the assembly of iron rails in the transversal galleries and in the gallery that followed the progress of the vein. However the fact that R. Spengler reported in 1876 that the ore inside the mine was made in wheelbarrows, leads us to admit that such a system has never been installed. It is also in the 1872 Spengler report that is referred that only in September of 1871 that the tower elevation of the Eugénia well started operating using animals.
While the works did not reach great depths, the sewage was ensured by a gallery that discharged W of Mostardeira. The bilge pumps powered by steam engine only started working at the main well in 1870. In the following year, when the well was 140 m depth the pumps failed and the mine became flooded. This flood caused major damage due to the rubble of shafts and galleries. The production never have reached very high values. The values of 1871, when the mine was fully labored, refer 330 tons of raw ore with 2.2% Cu.
Before the bleaching tests and installation of the rosting oven the ore mined was essentially for exportation. It was simply crushed by men with mallets and chosen by women’s hands. The discovery of native copper in the Glória well led to propose the installation of cementation tanks but there is no sure indication that this method has ever been applied. From the existing reports it can be concluded that the mine employed annually between 30 and 80 workers, an amount that varied with the fluctuations of the exploration. While only men worked in the depths, the choice of the ore also occupied women and boys who were paid lower salaries.
The low economic interest of the deposit which had to compete with more productive ones and the difficulties in removing the quite sturdy rock were perhaps the main reasons for abandoning the mine.
An inventory done in 1920 for the purpose of sharing between the heirs of João de Matos includes: a mine in ruins, eight water wells, a bread oven oser, a dwelling for the engineer, seventeen houses of miners, a home for experiments with ore and annexed land with olive trees. Almost all still exist except for the machinery and the equipment.
The places that mostly stand out in all the small mining neighborhood built on the hill of Mostardeira in 1863, are the ruins of the house where the steam engine was and the impressive ruins of the treatment facilities. This heritage is a set of great architectural, historic and scenic interest without equivalent throughout the Ossa-Morena Zone.
(*) Brandão, José Manuel; Matos, João Xavier - Memórias do cobre: nota sobre a criação de um parque arqueo-industrial na Mina da Herdade da Mostardeira (Estremoz, Portugal). In: Libro de Actas del Primer Simposio sobre la Minería y la Metalurgía antigua en el Sudoeste Europeo, Centro d'Arqueología d'Avinganya, Serós, Segrià, Catalunya, España, del 5 al 7 de Mayo de 2000. Segrià: SEDPGYM, 2002, Vol. 2, p. 483-493.
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Locality Updated: Mt Wyatt area, Whitsunday Region, Queensland, AustraliaFrom Steve Sorrell, 19th May 2013 05:43:10