|
|
 General Information > Outline of Mining |
 |
|
| |
 Mining History |
A. End of the Choseon Dynasty
With a self-sufficient economy based on the farming industry, all industries were underdeveloped. With the Mines Act of Korea promulgated in 1906 because of the prior occupation of Korea's mineral resources by the Imperialist Japanese, however, exploitation of minerals was easy and the development of the gold and silver, which were easily converted into cash, was revitalized.
B. During Japanese Colonial Rule
With the Mines Decree promulgated in 1915, exploitation of resources to supply war materials for Japanese Imperialists was conducted in full swing. Production of gold and silver, which is easily convertible into cash, as well as the production of strategic materials such as tungsten, iron, and anthracite, were encouraged. At the end of the Japanese Colonial Rule, the gold mining decree was enforced to increase production of gold. The development of mines was also monopolized.
C. After Independence
Under the leadership of the Bureau of Mining under the Ministry of Commerce and Industry, mineral products were exploited and exported for economic reconstruction. With general industrialization in its infancy, production of mineral products such as tungsten for export was emphasized. The export of mineral products accounted for 78% of total exports in 1953.
D. Economic Development Period
Korea Resources Corporation, a government-owned company, was established in 1967. The Ministry of Power and Resources was created in 1977 to enforce the mining policy designed to increase the production of Anthracite, a national fuel. At the same time, by developing general mines mainly composed of metal mines, production of energy minerals and raw mineral materials for key industries was encouraged.
E. Present
Anthracite for fuel has lost its international competitiveness. Since the latter part of the 1980s, the coal industry has been rationalized because of very poor development conditions and the trend in the use of clean and convenient energy. Most of metal mines were also shut down owing to very poor development conditions. Thus, the government resorted to importation. Currently, its imports account for 99% of its domestic consumption. With only two or three metal mines currently in normal operation, the importation of metal minerals from overseas has become inevitable. The development and market conditions of non-metal mines are very favorable. Non-metal mines account for 73% of domestic mineral production. With a high degree of industrialization, however, the importation of highly refined minerals is on the rise. |
| |
| Geology |
The Korean peninsula constitutes in general an eastern part of the Sino-Korean paraplatform except in a few minor regions on which Phanerozoic geological events took place in nearly the same fashion as those of northern China.
Archeozoic rocks compose the foundation of a paraplatform and crop out widely on Korean peninsula particularly in Kwanmobong, Nangnim, Gyeonggi and Yeongnam Massifs.
Proterozoic sequences resting upon the basement complex were known, prior to 1945, as the Macholloyong and Sangwon Systems in North Korea and the Yonchon and Okcheon Groups in South Korea. However, some more Proterozoic sequences have been identified in many regions. Recently, Precambrian formations have been more clearly defined, yet the tectonic movements and igneous activities during Precambrian are not precisely understood despite the fact that numerous age dating of these rocks were taken.
At the beginning of Cambrian, the sea invaded the paraplatform developing Pyongnam Basin in northwestern Korea, and northeastern part of the Okcheon Basin in mid-eastern Korea, both of which are believed to be connected through the western part of the East Sea, marine sediments had been deposited in these basins until mid-Ordovician time. The sediments in these basins are dominantly composed of calcareous marine sequences which are known as Choseon Supergroup.
It is believed that sedimentation virtually ceased from Middle Ordovician to Middle Carboniferous and this is known as the "Great Hiatus" in Korea. However, recent study has revealed that the Silurian carbonate sequence lies unconformably on the Ordovician carbonate sequences, so that it is reasonable to think that the Cambro-Ordovician sea has probably extended intermittently until the Silurian.
The granite ranging from late-Silurian to early-Devonian has been age-dated recently, indicating that metamorphism took place during Silurian. These facts together with sporadic outcrops of Silurian strata might suggest that a minor orogenic movement had taken place during what is known as the Great Hiatus.
After retreating during mid-Paleozoic, the sea invaded again the same basin area and also the Duman River Basin to the extreme northeastern region of Korea in Middle Carboniferous where shallow marine sediments accumulated in an early stage with thick non-marine sediments deposited during mid to late stage. The sequence known as the so-called "Pyeongan System" covers from Late Carboniferous to Early Triassic. Important coal beds (anthracite) were embedded in the Permian strata.
In Middle Triassic time, an orogenic movement took place and affected all sedimentary strata of the intra-cratonic basins in the Sino-Korean Paraplatform causing faulting and folding in them. This is known as the "Songnim Disturbance".
The movement was generally believed to be more severe in North Korea where granites of Triassic age were intruded, but no such granites are known in South Korea. Judging from regional distribution of the Pyeongan and Daedong Supergroup of the Late Triassic to Jurassic age in South Korea, the Songnim Disturbance was quite severe too in the south in contrast to the established theory thus far, and some geologists believe that the west-northwest trend of basin structure in the northeastern parts of Okcheon zone were manifestation of the structures originated by the Songnim Disturbance.
The Songnim Disturbance left behind some small scattered intermontane basins in the previous sedimentary basins, namely, Pyeongnam, the Okcheon Neogeosynclinal Zone and the southwestern part of the Gyeonggi Massifs, where the Daedong Supergroup and equivalent sequences of terrestrial origin were deposited during Late Triassic to Jurassic.
The Daedong Supergroup possesses a different lithology and sequence in the different basins, but is characterized by the presence of numerous conglomerate beds. It contains mineable coal beds in some areas. These conglomerate beds may testify to tectonic instability during the Jurassic, revealed also by the extensive distribution of granites whose age ranges from Early- Jurassic to Early-Cretaceous. These facts indicate that the Songnim Disturbance continued to the ensuing orogeny which is designated as the "Daebo Orogeny" of Jurassic.
The Daebo Orogeny was so severe in intensity that all the previous formations were intensely deformed and some were mildly metamorphosed. The granite batholiths in the Gyeonggi and Yeongnam massifs and the Okcheon folded belt are aligned in a direction of southwest to northeast diagonally across the Korean peninsula. The Okcheon folded belt itself also trends in the same direction, so that it is believed that the belt was generated by the Daebo Orogeny.
Following the Daebo Orogeny a large Cretaceous basin was formed in south-eastern part of Korea, and in various scattered troughs where non-marine sediments, volcanoclastic and volcanic rocks were accumulated. This sequence composes the Gyeongsang Supergroup. A thick pile of volcanoclastic and volcanic rocks in the upper part of the Supergroup consist of acidic to intermediate effusive rocks, lavas and tuffs. The intrusion of the Bulguksa granite followed mainly in the basin area and its adjacent localities. It has been previously known that the emplacement of Bulguksa granite terminated at the end of Cretaceous time, but recent age dating has revealed that it continued to the early Paleogene. Important mineral deposits in Korea are related to these Late- Cretaceous plutonism particularly in South Korea. The chemical composition and the age of igneous rocks, tectonic arrangement and zoned distribution of mineral deposits in Gyeongsang Basin revealed strongly that plate tectonics played an important role in geological and tectonic settings since the Late-Cretaceous in Gyeongsang Basin.
By the end of Cretaceous to Early Paleogene, the Korean peninsula had assumed its present shape and the Neogene sequences accumulated in few small basins along the east coast and in some scattered troughs. Tertiary sediment is composed mostly of earlier nonmarine and later marine strata of Miocene and Pliocene. An unconformity in the Mid-Miocene between the nonmarine and marine strata is found. The former strata were mildly deformed and also associated with volcanic sediment. This break is known as "Yonil Disturbance".
Continuing from the previous one, Quarternary alkali basalt volcanic activity was widely spread in Mt. Baekdoosan, Ullung and Cheju Islands, Chugaryong Rift Valley and in some small scattered troughs. The major stratigraphic units and tectonic movements mentioned above is summarized below. |
| |
| Major mine |
 |
|
|
