The Palencia mining basin is a Spanish coal mining area located on the southern slope of the Cantabrian mountain range. It owes its name to its location, in the north of the province of Palencia, in the region of Montaña Palentina. Its main exploitations are black coal and anthracite.
Palencia's Carboniferous outcrops are located in the so-called Pisuerga-Carrión Unit, a metamorphic area that constitutes the easternmost part of the geological regions of the Cantabrian Area. They extend for about 55 km in a SW-NE direction in the north of the province. Alt URL
The discovery of coal in this area took place in 1838 between the towns of Orbó and Barruelo, in the eastern part of the basin, so they were the first areas to begin its exploitation. Coal mining completely changed the economy and demography of the region, becoming its main economic means and facilitating the installation of infrastructures for its transport, such as La Robla railway and the Barruelo–Quintanilla de las Torres railway branch.
It was the country's main source of energy during the autarky of the 1950s, but from the 1960s onwards it began a period of recession when it was replaced by other hydrocarbons, and received its final blow with Spain's entry into the European Economic Community in 1986, which led to the closure of all unprofitable installations. During the nineties, all mining operations were gradually closed, until they were reduced to two underground mines in Velilla del Río Carrión and two open-pit mines in the municipalities of Guardo and Castrejón de la Peña. In 2012 UMINSA announced the indefinite closure of all its mines in the province, which was carried out throughout 2014.
The influence of almost two centuries of mining activity has been very important in aspects such as the natural landscape, demography, economy, sociology and culture of the area.
Geographical context
Topography
Montaña Palentina is a natural region characterized by the mountainous landscape that gives it its name. It is located in the central sector of the Cantabrian Mountain Range, and its relief is characterized by a strong contrast between the river valleys and the mountainous elevations. The Ministry of Agriculture grants the region the status of High Mountain Area, according to Law 25/1982. Within it are distinguished, from west to east, three mountainous areas:
Fuentes Carrionas and La Pernía Occidental, in the westernmost part of the area, next to the provincial borders with Cantabria and León, where the highest elevations of the region are located: Curavacas (2520 masl), Espigüete (2450 m) and Pico Murcia (2431 m).Peña Prieta (2538 m) has been excluded because its summit is in Cantabria. Sierra del Brezo and La Peña, extending some 30 km from Fuentes Carrionas to the Pisuerga basin, with Peña del Fraile (2025 m) and Peña Redonda (1993 m) as the highest peaks.ƒ Sierra Braña, Sierra de Peña Labra and Sierra de Híjar, in the easternmost part of the region, next to the provincial border with Cantabria. Its most representative peaks are Valdecebollas (2139 m), Peña Sestil (2063 m) and Peña Labra (2029 m).
In Montaña Palentina there are two important sedimentary basins, the Douro basin, with the source in the area of two important affluents: the Carrión and the Pisuerga; and the Ebro basin, which crosses a small portion to the NE of the region.
Geographic subdivision
Ricardo Becerro de Bengoa, one of the first historians to document the basin, established in 1874 in his Libro de Palencia the first geographical subdivision of the Palencia mining area:
Rubagón basin: the area around the Rubagón river, with Barruelo de Santullán and Orbó as main centers. Carrión basin: in the vicinity of the Carrión river, with the farms of Guardo, Velilla del Río Carrión and Santibáñez de la Peña as centers. Pisuerga basin: mining operations north of Cervera de Pisuerga, mainly La Pernía and San Salvador de Cantamuda.
This subdivision carried out in the 19th century has continued to be considered valid by modern authors.
Subdivision by rank
Black Coal Black coal is mainly found around the Santullán valley, with the main center being the town of Barruelo. It was the geologist Casiano de Prado who was the first to study the León and Palencia coal basins. According to a study published in 1875 by Román Oriol y Vidal, the coal layers were mainly found in Valle, Orbó, Barruelo and San Cebrián de Mudá, although they also extended as far as Guardo in the western part and towards Verdeña, San Salvador de Cantamuda, Lores and Piedrasluengas in the north. According to this study, there are 16 layers of coal in the valley divided into three groups: the lower group, comprising the four oldest layers of the formation, which were already being exploited at the time; the middle group, made up of eight layers, also being exploited; and the upper group, composed of three layers of good condition and a fourth of poor quality. From the lower to the middle group it was estimated a distance of 100 m, and from this one to the upper one a distance of about 500 m, being the thickness of each layer of approximately one meter. Its reserves are estimated at 75 million tons, plus another probable 50 million tons.
Anthracite The anthracite basin is located in the northwest of the province, from the border with the province of León to Cervera de Pisuerga. It is a narrow strip bounded to the north by the mountainous elevations of Fuentes Carrionas and Sierra del Brezo and to the south by the towns of Velilla del Río Carrión, Guardo, Santibáñez de la Peña, Castrejón de la Peña and Dehesa de Montejo. Further north, there is another center around La Pernía and San Salvador de Cantamuda.
This area is estimated to consist of ten to twelve anthracite layers of varying quality, approximately one meter thick. Reserves are estimated to be about 85 million tons certain plus another probable 20 million tons.
Geology
General geology
The Palencia mining basin is located on the so-called Pisuerga-Carrión Unit, which is the easternmost part of the geological regions of the Cantabrian Area.
It is composed of Paleozoic materials on which the Quaternary deposits of the northern end of the Douro basin are based. The Carboniferous system, which extends for about 55 km in a SW-NE direction through the north of the province of Palencia, is characterized by the presence of series of sediments with important facies variations. Alt URL The outcrops of the Lower Carboniferous are very homogeneous and are linked to the Devonian, so they are considered pre-orogenic, while from the Namurian onwards their composition is much more complex and varies depending on the area, having differentiated at least five areas with different stratigraphic characteristics.
The carboniferous sediments of the Palencia basin belong to four sequential periods marked by successive tectonic phases: Westphalian, Stephanian and Lower Pre-Permian. Although both basins (coal and anthracite) were intensely folded during the Asturian phase of the Westphalian A, their origin, as shown below, is different.
Geology by area
Black coal basin The black coal basin dates to the Westphalian B phase of the Carboniferous period. Sedimentation in this basin was mainly deltaic, composed mainly of marine phases between which continental episodes were interspersed with coal beds. Filling took place during two stages: Westphalian B basal deposits and Westphalian C shales, peats and limestones.
In this subarea of Barruelo, of mainly marine sedimentation, the thickness of the sedimentary succession is about 8000 m. Six lithostratigraphic units with coal layers have been distinguished, with the following yield:
Peña Cildá Formation: >500 m Barruelo Formation: 1200 m Brañosera Formation: 870 m Ojosa Formation: >2200 m Vergaño Formation: 1350 m
Anthracite basin The Guardo-Cervera subarea belongs to the Westphalian D period. Unlike the Barruelo subarea (predominantly marine), this basin is of continental influence. Its sedimentary series rests on the remains of the Devonian and Lower Carboniferous, and is composed of mainly continental sections alternating with marine ones.
The carboniferous belt that extends from Guardo to Cervera de Pisuerga is originated by the alpine movement that gave rise to the Sierra del Brezo, which dragged a carboniferous formation from the interior of the plateau to fold over the Cantabrian mountain range, forming a fault where the carboniferous deposits are located.
Petrography According to a study published in the specialized journal Geogaceta in 2006, coals from the Guardo-La Pernía area reach the anthracite grade depending on their volatile matter content. Alt URL It also indicates that the high rank reached by the coals in this area, as well as the presence of natural coke and pyrocarbons in them, implies their exposure to high temperatures and an important thermal alteration. As a conclusion, it is pointed out that the tectonics of the area has had an important influence on the range and the physical-structural characteristics of its coals. Alt URL
The coal from the Santullán valley and Rubagón basin is classified as black coal, and belongs to the so-called Northern Coal Formation, which also includes the deposits of Asturias and León, with which it shares characteristics. Hard coal is an organic sedimentary rock, a type of coal formed by the compression of lignite.
Mining activity
History
Context
Two facts conditioned the beginning of mining activity in the northern part of the province of Palencia: the need for coal for the new technology that arose after the Industrial Revolution and the new mining legislation enacted in Spain at the time.
The appearance of the steam engine, the driving force of the industrial revolution that began in the second half of the 18th century, increased the world's consumption of fossil fuels, especially coal. Alt URL Its application to the railroad, the means of transportation that revolutionized this era, led to the mine, the factory and the railroad as the generating agents.
In Spain, the need to liberalize the mining sector and favor private initiative allowed successive modifications in the legislation, and the reform carried out by Fausto de Elhuyar in 1825 under the reign of Ferdinand VII was followed by the definitive Mining Law of 1868, which allowed the definitive transfer of the ownership of the mines, previously owned by the Crown, to the hands of private investors. Alt URL
The beginning of coal mining in Spain was in Asturias, where the mining engineer Guillermo Schulz carried out between 1832 and 1834 a precise geological study that allowed the exact location of the black coal deposits. At the end of the 1830s, the first mining companies were born in the area, which would give rise to other more powerful ones, such as Duro Felguera.
First prospections
Black coal basin
The versatile Ricardo Becerro de Bengoa attributes in his writings the discovery of coal in the Montaña Palentina to the parish priest of Salcedillo, Ciriaco del Río, in 1838. According to Becerro de Bengoa, the priest (who a few days before had read an article in a newspaper about coal and its exploitation) was returning one afternoon from Aguilar de Campoo when, between the towns of Orbó and Barruelo, he found some pieces of black stone on his way. Alt URL After verifying that the mineral burned and kept the heat, he ascertained the presence of greater quantities, contacting the mining company Collantes of Reinosa to begin the exploitation of the deposit. This thesis is maintained by the existing historiography on the subject.