Los Ríos Region
The Los Ríos Region (Spanish: ''Región de Los Ríos'', , ''Region of the Rivers'') is one of Chile's 16 regions, the country's first-order administrative divisions. Its capital is Valdivia. It began to operate as a region on October 2, 2007, ...
,
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
. Mulpún lies in the commune of
Máfil
Máfil (Mapudungun for ''embraced between rivers'') is a town and commune of the Valdivia Province, Los Ríos Region in southern Chile, about 30 km northeast of Valdivia. The main economic activities of Máfil are forestry, cattle farming, c ...
a few kilometers to the west of the
Chile Route 5
Chile Highway 5 or Route 5 known locally as ''Ruta 5'' is Chile's longest route, . It is part of the Pan-American Highway.
Stretch
It runs from the Peruvian border connecting with Peru Highway 1 north of Arica to Puerto Montt where it connects ...
The mine was exploited during parts of the 20th century when its coal powered the electric grid of the city of
Valdivia
Valdivia (; Mapuche: Ainil) is a city and commune in southern Chile, administered by the Municipality of Valdivia. The city is named after its founder Pedro de Valdivia and is located at the confluence of the Calle-Calle, Valdivia, and Cau-Cau R ...
. The mine has been owned by ''Compañía Carbonífera San Pedro de Catamutún'' since 1987. In 1992 and 1993 a
gravimetric
Gravimetry is the measurement of the strength of a gravitational field. Gravimetry may be used when either the magnitude of a gravitational field or the properties of matter responsible for its creation are of interest.
Units of measurement
Gr ...
exploration
Exploration refers to the historical practice of discovering remote lands. It is studied by geographers and historians.
Two major eras of exploration occurred in human history: one of convergence, and one of divergence. The first, covering most ...
campaign was conducted. The mine was planned to re-open in 1997. As the Catamutún mines closed in the late 1990s some miners were transferred to Mulpún, but mining in Mulpún ended in 2001 after an explosion accident.
An
underground coal gasification
Underground coal gasification (UCG) is an industrial process which converts coal into product gas. UCG is an ''in-situ'' gasification process, carried out in non-mined coal seams using injection of oxidants and steam. The product gas is brought t ...
project in the closed Mulpún mine was made public in 2009 but was put on hold in 2013. The project was a
joint-venture
A joint venture (JV) is a business entity created by two or more parties, generally characterized by shared ownership, shared returns and risks, and shared governance. Companies typically pursue joint ventures for one of four reasons: to acces ...
At Mulpún there is one sub-horizontal coal layer whose thickness vary from 9 to 11 m. The coal is
sub-bituminous Sub-bituminous coal is a lower grade of coal that contains 35–45% carbon. The properties of this type are between those of lignite, the lowest grade of coal, and those of bituminous coal, the second-highest grade of coal. Sub-bituminous coal i ...
type. Geologically the coal layers of Mulpún are belong to the so-called Mulpún Beds, a unit similar to the Pupunahue Beds that extends across large of the sub-surface of Los Ríos Region and whose coal has also been mined at
Catamutún Catamutún is a coal mine and locality in Los Ríos Region, Chile.Pupunahue. The coal layers are of Oligo-
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
age and lie near the base of Pupunahue Beds. Below these lies the
basement
A basement or cellar is one or more floors of a building that are completely or partly below the ground floor. It generally is used as a utility space for a building, where such items as the furnace, water heater, breaker panel or fuse box, ...
which is made up by the
Bahía Mansa Metamorphic Complex
The Bahía Mansa Metamorphic Complex or BMMC ( es, link=no, Complejo metamórfico Bahía Mansa, CMBM), also known as the Western Series, is a group of metamorphic geologic formations of the Chilean Coast Range in southern Chile. It consists main ...
. The Mulpún Bedsare overlaid across an angular uncorformity by
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
deposits. The coals of Mulpún and the whole Mulpún Beds lie in Mulpún Basin, a sub-basin of the larger Pupunahue-Mulpún Neogene Carboniferous Basin.
The sedimentary strata have been interpreted to reflect the former existence of four distinct environments:
*A fluvial
estuary
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...
with
sand bar
In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It o ...
s and
peat
Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficien ...
accumulations
*A slightly saline
swamp
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
with peat accumulations
*A
tidal flat
Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal fl ...
*A
continental shelf
A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...