16

Rio de Frades mines


The path of the black gold

The tungsten and tin exploration in the zone of the Rio de Frades mines is dated back to at least 1921-22, when the first licenses to the mining exploration for this area were granted. The W-Sn field of Rio de Frades is placed along a fault system, with the N-S approximate direction, occurring on early Ordovician metasedimentary rocks and at west of the Regoufe plutonite. The metasomatic effects caused by the proximity of an apophysis in the Regoufe granite in the edge of the contact aureole with the mentioned metasediments were the responsible for the quartz veins’ mineralization, that are rich in wolframite (the most abundant), cassiterite and, more exceptionally, scheelite. The arsenopyrite is the main sulfide identified, occurring others like pyrite, sphalerite, marcasite, pyrrhotite, stannite and native bismuth. 

In 1923, the Companhia Mineira do Norte de Portugal was founded. As it worked with German captains, it was also known as “Companhia Alemã” (German company), and it was dedicated to the exportation of tungsten to Germany. In 1941 occurred the period of the biggest activity of exploration and exportation of tungsten to Germany. According to some estimates, there were more than 3000 people working in this field. Being the mining company with a bigger number of concessions and, consequently, a bigger territorial area, the “Companhia Alemã” realized most of the investments and improvements of the region, such as an electric transformer substation, a compressor central with very powerful electric compressors, and even a temporary station for the GNR (National Republican Guard). There was also an improvement of the social conditions of the facilities, both for the managerial staff and the workers, namely in the construction of more and better houses, an infirmary, a medical office, a canteen, a barbershop and a shower room, with compartments for men and women, as well as sanitation works.

The ruins of the Frades mining exploration and facilities are spread among three main cores: a) the traditional village with schist houses, b) the “Bairro de Cima”, a set of old residences of the technical and administrative staff of the mines, some of them still occupied by their family; and c) main core of the mines work area, located in the valley bottom, constituted by the office building, infirmary and medical office, laundry, settling tanks, garages and other technical facilities, as well as the Santa Bárbara chapel. In the slopes of the mining pole, it is also possible to observe the remains of old houses of miners and warehouses, as well as several galleries, with particular reference to the gallery of the Cerdeira valley that, according to some historical data and people’s memories, was the most productive in terms of tungsten when compared to all of the mining concessions of Rio de Frades. Nowadays, it can be crossed through a trail of about 200 m, bringing memories of the past mining stories. After crossing this gallery, we can see a beautiful waterfall in the tributary stream of the Frades river, as the result of a dike built to carry water to a superior spot through the gallery to the mining complex. Rio de Frades is also the best river for practicing canyoning on the Arouca Geopark territory.

Useful information

Rio de Frades, União de Freguesias de Albergaria da Serra e Cabreiros
330 m
40.515318 | -8.170646

Other geosites

_MG_9935.jpg
1

Panorâmica do Detrelo da Malhada

Explore
Côto do Boi
2

Côto do Boi

Explore
S. Pedro Velho
3

S. Pedro Velho

Explore
Marmitas de gigante
4

Marmitas de Gigante do Caima

Explore
Contacto Litológico da Mizarela
5

Contacto Litológico da Mizarela

Explore
Frecha da Mizarela
6

Frecha da Mizarela

Explore
_MG_9717.jpg
7

Pedras Parideiras

Explore
Dobras da Castanheira
8

Campo de dobras da Castanheira

Explore
_MGL0623.jpg
9

Filão de quartzo de Cabaços

Explore
Torre Meteorológica 8.jpg
10

Panorâmica da Costa da Castanheira

Explore
2600.jpg
11

Pedras Boroas do Junqueiro

Explore
_MGL0754.jpg
12

Pias do Serlei

Explore
Pedras Cebola 4.jpg
13

Quartzodiorito de Espinho (Pedras Cebola)

Explore
Viveiros Granja 4.jpg
14

Bolas Quartzodioríticas dos Viveiros da Granja (Pedras Cebola)

Explore
DSC06279.JPG
15

Minas da Pena Amarela

Explore
123.jpg
17

Icnofósseis de Mourinha

Explore
128.jpg
18

Livraria do Paiva

Explore
Conheiros de Janarde
19

Conheiros de Janarde

Explore
78.jpg
20

Meandros do Paiva

Explore
Icnofósseis da área de Meitriz
21

Icnofósseis de Meitriz

Explore
36.jpg
22

Minas de Regoufe

Explore
_MG_8381.jpg
23

Portal do Inferno e Garra

Explore
_MG_8240.jpg
24

Panorâmica da Senhora da Mó

Explore
PO-01811_p106e107.jpg
25

Coleção de Fósseis do Centro de Interpretação Geológica de Canelas

Explore
IMG_2616.jpg
26

Glaciação ordovícica

Explore
IMG_2581.jpg
27

Afloramento do Silúrico inferior

Explore
IMG_2653.jpg
28

Conglomerado do Carbónico

Explore
96.jpg
29

Gralheira d'Água

Explore
Praia fluvial do Vau
30

Vau

Explore
IMG_5537.jpg
31

Gola do Salto

Explore
Aspectos geotectónicos de Espiunca
32

Falha da Espiunca

Explore
Icnofósseis da área de Vila Cova
33

Icnofósseis de Vila Cova

Explore
Icnofósseis da área de Vilarinho
34

Icnofósseis de Vilarinho

Explore
arouca_0206-27-2.jpg
35

Cascata das Aguieiras

Explore
2.jpg
36

Garganta do Paiva

Explore
15.jpg
37

Icnofósseis de Cabanas Longas

Explore
pag122e123_1_Avelino.jpg
38

Mira Paiva

Explore
Marco geodésico da Pedra Posta
39

Pedra Posta

Explore
PedraMa2.jpg
40

Pedra Má

Explore
Panorâmica da marco geodésico de Sobreiros
41

Panorâmica de Sobreiros

Explore