Sebuku (old spelling Seboekoe) is a island south-east of

Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and eas ...

and administratively part of

South Kalimantan South Kalimantan ( id, Kalimantan Selatan) is a Provinces of Indonesia, province of Indonesia. It is the smallest province in Kalimantan, the Indonesian territory of Borneo. The provincial capital was Banjarmasin until 15 February 2022 when it wa ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

. Sebuku is home to a large

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dea ...

mine operated by Straits Asia Resources, which produces 3 million tonnes of coal every year.

Overview

Sebuku is located to the south-east of Borneo, approximately from

Laut Island Laut (literally "sea") is an island in the Kota Baru Regency Kotabaru Regency is one of the eleven regencies in the Indonesian province of South Kalimantan. It consists of two parts; the smaller but more populated part comprises Laut Island , t ...

. It is roughly from north to south and from east to west at its widest point, covering a total area of . Administratively, it is part of

. It is on the Kanibungan Fault. Coal was first found on the island by the Dutch colonial government in 1925. Large deposits of coal, dating from the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

, have been found in Sebuku's south-west region; the main deposit forms a

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimpose ...

which trends from north to south. The

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

around the coal is mainly

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

and

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

. Sebuku is home to roughly 4,900 people, with a total population density of . Prior to the opening of the coal mine, it had no infrastructure; now there are small roads, a port, and a small airfield.

Mining

Although the Dutch originally discovered at least 25 coal deposits on Sebuku, after realizing that the island may not survive mining they cancelled their plans. Instead, they kept the island as a preserved park to serve as a buffer for Laut Island. Due to estimates of coal reserves measuring eleven million metric tonnes, infrastructure for a mine was built beginning in June 1997; mining began in December of the same year, despite concerns that the mining could sink the island. The mine is operated by

Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, borde ...

-based Straits Asia Resources, a subsidiary of Straits Resources. Mining is done using multiple

open pits Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow. This form of mining ...

. As of 30 June 2008, the total remaining coal was estimated at 384 megatonnes, with a reserve base of 19 megatonnes. Production is estimated to be 3 megatonnes per annum.

References

{{reflist Coal mines in Indonesia Islands of Kalimantan Landforms of South Kalimantan Populated places in Indonesia