자원환경지질 (Economic and Environmental Geology)

  • 제55권3호
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  • Pages.241-259
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  • 2022
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  • 1225-7281(pISSN)
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  • 2288-7962(eISSN)
대한자원환경지질학회 (The Korean Society of Economic and Environmental Geology)
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함희토류 탄층: 비전통적 희토류 광체로서의 가능성에 대한 고찰

Rare Earth Elements (REE)-bearing Coal Deposits: Potential of Coal Beds as an Unconventional REE Source

  • 최우현 (연세대학교 BK21 지구.대기.천문 교육연구단) ;
  • 박창윤 (경북대학교 지질학과)
  • Choi, Woohyun (BK21 Institute of Earth Atmosphere Astronomy, Yonsei University) ;
  • Park, Changyun (Department of Geology, Kyungpook National University)
  • 투고 : 2022.06.11
  • 심사 : 2022.06.14
  • 발행 : 2022.06.28
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초록

희토류 원소 (Rare Earth Elements; REE)는 전통적으로 카보나타이트나 풍화잔류광상에서 채광이 이루어졌다. 하지만, 최근 각종 첨단산업에 활용되는 희토류 원소의 수요증가로 인해, 추가적인 희토류 부존량 확보를 위한 비전통적인 희토류 광상으로서 함희토류 탄층이 주목받고 있다. 함희토류 탄층은 일반적인 탄층보다 높은 농도 (> 300 ppm)의 희토류 원소를 함유하는 탄층을 의미한다. 이는 크게 3가지 성인유형으로 분류되며, 두가지 이상 성인의 복합작용으로 형성되기도 한다. 우선, 육성형 (terrigenous) 함희토류 탄층은 주로 보크사이트 광상 기원 광물들의 이동 및 재퇴적에 의해 형성되며, 주로 LREE (Light REE)가 부화된다. 응회질형 (tuffaceous) 함희토류 탄층은 화산 분출에 기인한 화산재가 석탄 분지에 유입이 되어 형성된다. 이 유형은 주로 화산재기원의 함희토류 광물들과 자생기원의 인산염 광물들이 탄층과 톤스테인층의 경계부에 얇은 층상으로 농집되며, 희토류가 균질하게 분포하는 수평형 REE 패턴을 갖는다. 마지막으로, 열수형 (hydrothermal) 함희토류 탄층은 화성암기원 열수에 의해 희토류가 유입되어 형성된다. 이러한 탄층에서는 함할로겐 인산염 광물들과 함수광물들이 세립질의 자생형으로 존재하며, 주로 HREE (Heavy REE)가 부화된다. 미국은 이미 켄터키주 파이어 클레이 탄층을 대상으로 탐사로부터 선별 및 공정개발을 통해 고순도 산화 희토류의 생산에 성공하였으며, 연간 희토류 소비량의 약 7% 공급을 목표로 연구를 확장하고 있다. 한국의 경우, 경주-영일 탄전의 갈탄층이 응회암층과 함탄층이 협재하는 특징을 보이고, 압밀작용의 영향이 상대적으로 적은 신생대 제3기의 연대를 갖는 것으로 보아 응회질형 함희토류 탄층으로서의 개발 가능성이 기대된다. 따라서, 국내 희토류 공급망 다각화를 위해 함희토류 탄층 대상의 광물, 광상 및 퇴적학적 연구를 통한 개발 가능성 평가가 우선적으로 요구된다.

In general, the REE were produced by mining conventional deposits, such as the carbonatite or the clay-hosted REE deposits. However, because of the recent demand increase for REE in modern industries, unconventional REE deposits emerged as a necessary research topic. Among the unconventional REE recovery methods, the REE-bearing coal deposits are recently receiving attentions. R-types generally have detrital originations from the bauxite deposits, and show LREE enriched REE patterns. Tuffaceous-types are formed by syngenetic volcanic activities and following input of volcanic ash into the basin. This type shows specific occurrence of the detrital volcanic ash-driven minerals and the authigenic phosphorous minerals focused at narrow horizon between coal seams and tonstein layers. REE patterns of tuffaceous-types show flat shape in general. Hydrothermal-types can be formed by epigenetic inflow of REE originated from granitic intrusions. Occurrence of the authigenic halogen-bearing phosphorous minerals and the water-bearing minerals are the specific characteristics of this type. They generally show HREE enriched REE patterns. Each type of REE-bearing coal deposits may occur by independent genesis, but most of REE-bearing coal deposits with high REE concentrations have multiple genesis. For the case of the US, the rare earth oxides (REO) with high purity has been produced from REE-bearing coals and their byproducts in pilot plants from 2018. Their goal is to supply about 7% of national REE demand. For the coal deposits in Korea, lignite layers found in Gyungju-Yeongil coal fields shows coexistence of tuff layers and coal seams. They are also based in Tertiary basins, and low affection from compaction and coalification might resulted into high-REE tuffaceous-type coal deposits. Thus, detailed geologic researches and explorations for domestic coal deposits are required.

키워드

과제정보

이 논문은 한국연구재단 우수신진연구사업 (NRF-2022R1C1C1007661)에 의해 지원되었다. 논문의 질적 향상을 위해 건설적인 비평을 해주신 두 익명의 심사위원와 편집위원께 깊은 감사를 표한다.

참고문헌

  1. Ahn, J.-W., Lim, K.-M., Park, S.-W., Kim, J.-Y., Shin, H.-Y., Park, J.-K., Kim, G.-M., Kim, K.-Y., Lee, S.-H., Hong, H.-J. and Lee, M.-H. (2021). Development of Rare Earth Element Recovery Technologies based on Carbon Mineralization Technology. Korea Institute of Geoscience and Mineral Resources, 307p.
  2. Aide, M.T. and Aide, C. (2012). Rare earth elements: their importance in understanding soil genesis. Int. Scholarly Res. Notices, v.2012, 783876. doi: 10.5402/2012/783876
  3. Andrews, M. and Fuge, R. (1986). Cupriferous bogs of the Coed y Brenin area, North Wales and their significance in mineral exploration. Appl. Geochem., v.1(4), p.519-525. doi: 10.1016/0883-2927(86)90057-0
  4. Arapov, Y.A., Boitsov, V.E. and Kremchukov, G.A. (1984). Uranium Deposits of Czechoslovakia. Nedra, Moscow. 445p.
  5. Arbuzov, S., Ershov, V., Potseluev, A. and Rikhvanov, L. (2000). Rare elements in coals of the Kuznetsk Basin. Kemerovo, Russia. 499p.
  6. Arbuzov, S., Ershov, V., Rikhvanov, L. and Rikhvanov, L. (2003). Rare-Metal Potential of Coals in the Minusa Basin. Acad. Sci. (Siberian Division): Novosibirsk, Russia, 347p.
  7. Arbuzov, S. and Mashen'kin, V. (2007). Oxidation zone of coalfields as a promising source of noble and rare metals: a case of coalfields in Central Asia. Problems and Outlook of Development of Mineral Resources and Fuel-Energetic Enterprises of Siberia, p.26-31.
  8. Armands, G. (1961). Geochemical prospecting of a uraniferous bog deposit at Masugnsbyn, northern Sweden. In: Kvalheim, A. (Ed.), Geochemical Prospecting in Fennoscandia, p.127-154.
  9. Bao, Z. and Zhao, Z. (2008). Geochemistry of mineralization with exchangeable REY in the weathering crusts of granitic rocks in South China. Ore Geol. Rev., v.33(3-4), p.519-535. doi: 10.1016/j.oregeorev.2007.03.005
  10. Birk, D. and White, J.C. (1991). Rare earth elements in bituminous coals and underclays of the Sydney Basin, Nova Scotia: Element sites, distribution, mineralogy. Int. J. Coal Geol., v.19(1-4), p.219-251. doi: 10.1016/0166-5162(91)90022-b
  11. Boyle, R. (1977). Cupriferous bogs in the Sackville area, New Brunswick, Canada. J. Geochem. Explor., v.8(3), p.495-527. doi: 10.1016/0375-6742(77)90094-2
  12. Cannon, H.L. (1955). Geochemical relations of zinc-bearing peat to the Lockport dolomite, Orleans County, New York. USGS Bull., p.119-185. doi: 10.3133/b1000d
  13. Chalmers, D. (1990). Brockman multi-metal and rare earth deposit. Geology of the mineral deposits of Australia and Papua New Guinea, v.1, p.707-709.
  14. Chi, R. and Tian, J. (2008). Weathered crust elution-deposited rare earth ores. Nova Science Publishers. New York, 288p.
  15. Crowley, S.S., Stanton, R.W. and Ryer, T.A. (1989). The effects of volcanic ash on the maceral and chemical composition of the C coal bed, Emery Coal Field, Utah. Organ. Geochem., v.14(3), p.315-331. doi: 10.1016/0146-6380(89)90059-4
  16. Dai, S. and Finkelman, R.B. (2018). Coal as a promising source of critical elements: Progress and future prospects. Int. J. Coal Geol., v.186, p.155-164. doi: 10.1016/j.coal.2017.06.005
  17. Dai, S., Finkelman, R.B., French, D., Hower, J.C., Graham, I.T. and Zhao, F. (2021). Modes of occurrence of elements in coal: A critical evaluation. Earth-Sci. Rev., v.222, 103815. doi: 10.1016/j.earscirev.2021.103815
  18. Dai, S., Jiang, Y., Ward, C.R., Gu, L., Seredin, V.V., Liu, H., Zhou, D., Wang, X., Sun, Y. and Zou, J. and Ren, D. (2012). Mineralogical and geochemical compositions of the coal in the Guanbanwusu Mine, Inner Mongolia, China: Further evidence for the existence of an Al (Ga and REE) ore deposit in the Jungar Coalfield. Int. J. Coal Geol., v.98, p.10-40. doi: 10.1016/j.coal.2012.03.003
  19. Dai, S., Li, D., Chou, C.-L., Zhao, L., Zhang, Y., Ren, D., Ma, Y. and Sun, Y. (2008). Mineralogy and geochemistry of boehmiterich coals: new insights from the Haerwusu Surface Mine, Jungar Coalfield, Inner Mongolia, China. Int. J. Coal Geol., v.74(3-4), p.185-202. doi: 10.1016/j.coal.2008.01.001
  20. Dai, S., Li, D., Ren, D., Tang, Y., Shao, L. and Song, H. (2004). Geochemistry of the late Permian No. 30 coal seam, Zhijin Coalfield of Southwest China: influence of a siliceous low-temperature hydrothermal fluid. Appl. Geochem., v.19(8), p.1315-1330. doi: 10.1016/j.apgeochem.2003.12.008
  21. Dai, S., Li, T., Jiang, Y., Ward, C.R., Hower, J.C., Sun, J., Liu, J., Song, H., Wei, J. and Li, Q., Xie, P. and Huang, Q. (2015). Mineralogical and geochemical compositions of the Pennsylvanian coal in the Hailiushu Mine, Daqingshan Coalfield, Inner Mongolia, China: Implications of sediment-source region and acid hydrothermal solutions. Int. J. Coal Geol., v.137, p.92-110. doi: 10.1016/j.apgeochem.2003.12.008
  22. Dai, S., Liu, J., Ward, C.R., Hower, J.C., French, D., Jia, S., Hood, M.M. and Garrison, T.M. (2016). Mineralogical and geochemical compositions of Late Permian coals and host rocks from the Guxu Coalfield, Sichuan Province, China, with emphasis on enrichment of rare metals. Int. J. Coal Geol., v.166, p.71-95. doi: 10.1016/j.coal.2015.12.004
  23. Dai, S., Luo, Y., Seredin, V.V., Ward, C.R., Hower, J.C., Zhao, L., Liu, S., Zhao, C., Tian, H. and Zou, J. (2014). Revisiting the late Permian coal from the Huayingshan, Sichuan, southwestern China: Enrichment and occurrence modes of minerals and trace elements. Int. J. Coal Geol., v.122, p.110-128. doi: 10.1016/j.coal.2013.12.016
  24. Dai, S., Ren, D., Chou, C.-L., Li, S. and Jiang, Y. (2006). Mineralogy and geochemistry of the no. 6 coal (Pennsylvanian) in the Junger Coalfield, Ordos Basin, China. Int. J. Coal Geol., v.66(4), p.253-270. doi: 10.1016/j.coal.2005.08.003
  25. Dai, S., Ren, D., Hou, X. and Shao, L. (2003). Geochemical and mineralogical anomalies of the late Permian coal in the Zhijin coalfield of southwest China and their volcanic origin. Int. J. Coal Geol., v.55(2-4), p.117-138. doi: 10.1016/s0166-5162(03)00083-1
  26. Dai, S., Ren, D., Tang, Y., Yue, M. and Hao, L. (2005). Concentration and distribution of elements in Late Permian coals from western Guizhou Province, China. Int. J. Coal Geol., v.61(1-2), p.119-137. doi: 10.1016/j.coal.2004.07.003
  27. Dai, S., Xie, P., Jia, S., Ward, C.R., Hower, J.C., Yan, X. and French, D. (2017). Enrichment of U-Re-V-Cr-Se and rare earth elements in the Late Permian coals of the Moxinpo Coalfield, Chongqing, China: Genetic implications from geochemical and mineralogical data. Ore Geol. Rev., v.80, p.1-17. doi: 10.1016/j.oregeorev.2016.06.015
  28. Dai, S., Yan, X., Ward, C.R., Hower, J.C., Zhao, L., Wang, X., Zhao, L., Ren, D. and Finkelman, R.B. (2018). Valuable elements in Chinese coals: A review. International Geology Review, v.60(5-6), p.590-620. doi: 10.1080/00206814.2016.1197802
  29. Dai, S., Zhang, W., Ward, C.R., Seredin, V.V., Hower, J.C., Li, X., Song, W., Wang, X., Kang, H. and Zheng, L., Wang, P. and Zhou, D. (2013). Mineralogical and geochemical anomalies of late Permian coals from the Fusui Coalfield, Guangxi Province, southern China: influences of terrigenous materials and hydrothermal fluids. Int. J. Coal Geol., v.105, p.60-84. doi: 10.1016/j.coal.2012.12.003
  30. Dai, S., Zhou, Y., Ren, D., Wang, X., Li, D. and Zhao, L. (2007). Geochemistry and mineralogy of the Late Permian coals from the Songzo Coalfield, Chongqing, southwestern China. Sci. China Ser. D., v.50(5), p.678-688. doi: 10.1007/s11430-007-0001-4
  31. Danchev, V. and Strelyanov, N. (1979). Exogenic Uranium Deposits. Formation Conditions and Examination Methods: Izdvo Atomizdat, Moscow. 248p.
  32. Daukeev, S., Votsalevskiiy, E. and Pilifosov, V. (2002). Deep Structure and Mineral Resources of Kazakhstan. Oil and Gas [in Russian]. Almaty, v.3, p.110-115.
  33. Denson, N.M. (1959). Uranium in coal in the western United States (Vol. 1055). US Government Printing Office. 315p. doi: 10.3133/b1055
  34. Eskenazy, G., Mincheva, E. and Rousseva, D. (1986). Trace elements in lignite lithotypes from the Elhovo coal basin. Doklady Bolgarskoj akademii nauk. v.39(10), p.99-101.
  35. Finkelman, R.B. (1980). Modes of occurrence of trace elements in coal. University of Maryland, College Park. Ph.D. Thesis. 301p. doi: 10.3133/ofr8199
  36. Finkelman, R. B. (1993). Trace and minor elements in coal. Organ. Geochem., p.593-607. doi: 10.1007/978-1-4615-2890-6_28
  37. Gayer, R. and Rickard, D. (1994). Colloform gold in coal from southern Wales. Geology, v.22(1), p.35-38. doi: 10.1130/0091-7613(1994)022%3C0035:cgicfs%3E2.3.co;2
  38. Hower, J.C., Berti, D., Hochella Jr, M.F. and Mardon, S.M. (2018). Rare earth minerals in a "no tonstein" section of the Dean (Fire Clay) coal, Knox County, Kentucky. Int. J. Coal Geol., v.193, p.73-86. doi: 10.1016/j.coal.2018.05.001
  39. Hower, J.C., Eble, C.F., Backus, J.S., Xie, P., Liu, J., Fu, B. and Hood, M.M. (2020). Aspects of rare earth element enrichment in Central Appalachian coals. Appl. Geochem., v.120, 104676. doi: 10.1016/j.apgeochem.2020.104676
  40. Hower, J.C., Ruppert, L.F. and Eble, C.F. (1999). Lanthanide, yttrium, and zirconium anomalies in the Fire Clay coal bed, Eastern Kentucky. Int. J. Coal Geol., v.39(1-3), p.141-153. doi: 10.1016/s0166-5162(98)00043-3
  41. Ivanov, V., Katz, A.Y., Kostin, Y.P., Meitov, E. and Solov'ev, E. (1984). Economic types of natural germanium concentrations. Nedra, Moscow (in Russian). 246p.
  42. Jenney, W.P. (1903). The chemistry of ore-deposition. Am. Inst. Miner. Eng. Trans., v.33, p.445-498.
  43. Ketris, M.A. and Yudovich, Y.E. (2009). Estimations of Clarkes for Carbonaceous biolithes: World averages for trace element contents in black shales and coals. Int. J. Coal Geol., v.78(2), p.135-148. doi: 10.1016/j.coal.2009.01.002
  44. Kim, B.-K., Cheong, C.-H. and Kim, S.-J. (1975). Stratigraphic Studies on the Lignite-bearing Strata Distributed in the Yeongil District, North Gyeongsang-Do, Korea. J. Geol. Soc. Korea, v.11, p.240-252.
  45. Kim, Y.-J., Choi, M.-K., Seo, J.-H., Kim, B.-R. and Cho, K.-H. (2020). Current Research Trends for Recovery of Rare Earth Elements Contained in Coal Ash. Resources Recycling, v.29(6), p.3-14. doi: 10.7844/kirr.2020.29.6.3
  46. Kislyakov, Y.M. and Shchetochkin, V. (2000). Hydrogenic ore formation. Geoinformark, Moscow, 608p.
  47. Kler, V., Nenakhova, V., Saprykin, F.Y., Shpirt, M., Rokhlin, L., Kulachkova, A. and Iovchev, R. (1988). Metallogeny and geochemistry of coal-bearing and pyroschistbearing sequences. Concentration of Elements and methods of their Study. Nauka, Moscow, 256p.
  48. Klimanov, E.V. (2002). About mineralization in Jurassic strata of Angrensk Kaolin-Lignite deposit. Geol. Miner. Resurslar, v.2, p.23-27.
  49. Korostylev, P., Andrienko, G. and Andrienko, S. (2000). Mineralization of the Sinegorsky coal field. Geology and Mining of Primorye in the Past, Present, and Future., Dal'nauka Vladivostok, p.45-47.
  50. Koscheeva, I.Y., Tyutyunik, O.A., Chkhetiya, D.N. and Krigman, L.V. (2002). Osmium in coals of the Norilsk region. Proceedings of All-Russia Symposium on Geology, Genesis, and Development of Multicomponent Precious Metal Deposits. Svyaz-Print, Moscow, p.170-173.
  51. Kostin, Y.P. and Meitov, E. (1972). About genesis of high-germanium coal deposits and criteria of their exploration. Izvestia Akad Nauk USSR, Geol., v.1, p.112-119.
  52. Laudal, D.A., Benson, S.A., Addleman, R.S. and Palo, D. (2018). Leaching behavior of rare earth elements in Fort Union lignite coals of North America. Int. J. Coal Geol., v.191, p.112-124. doi: 10.1016/j.coal.2018.03.010
  53. Lee, H.-K., Moon, H.-S. and Oh, M.-S. (2007). Economics Mineral Deposits in Korea. Daewoo Academic Series.
  54. Lin, R., Soong, Y. and Granite, E.J. (2018). Evaluation of trace elements in US coals using the USGS COALQUAL database version 3.0. Part I: Rare earth elements and yttrium (REY). Int. J. Coal Geol., v.192, p.1-13. doi: 10.1016/j.coal.2018.04.004
  55. Lyons, P.C., Outerbridge, W.F., Triplehorn, D., Evans Jr, H.T., Congdon, R.D., Capiro, M., Hess, J. and Nash, W.P. (1992). An Appalachian isochron: a kaolinized Carboniferous air-fall volcanicash deposit (tonstein). Geol. Soc. Am. Bull., v.104(11), p.1515-1527. doi: 10.1130/0016-7606(1992)104%3C1515:aaiakc%3E2.3.co;2
  56. Mardon, S.M. and Hower, J.C. (2004). Impact of coal properties on coal combustion by-product quality: examples from a Kentucky power plant. Int. J. Coal Geol., v.59(3-4), p.153-169. doi: 10.1016/j.coal.2004.01.004
  57. Mashkovtsev, G.A., Kochenov, A.V. and Khaldei, A.E. (1995). On hydrothermal sedimentary formation of stratiform uranium deposits in Phanerozoic depressions. Rare-metal-Uranium Ore Formation within Sedimentary Rocks., Nauka, Moscow, p.37-51.
  58. Palmer, C. and Cameron, C. (1989). The occurrence of gold and arsenic in Sumatra, Indonesia, peat deposits. J. Coal Qual, v.8(3-4), p.122.
  59. Panov, B.S., Alekhin, V.I. and Yushin, A.A. (2001). Gold-bearing coals of the Dnieper brown coal basin. Geol. Coal Dep., v.11, p.248-252.
  60. Park, S.-U., Kim, J.-K., Seo, Y.-S., Hong, J.-S., Lee, H.-B. and Lee, H.-D. (2015). Evaluation of some rare metals and rare earth metals contained in coal ash of coal-fired power plants in Korea. Resources Recycling, v.24(4), p.67-75. doi: 10.7844/kirr.2015. 24.4.67
  61. Park, S.-W. (1990). Petrology and geochemistry of coals in Samcheog and Chungnam coalfields. Seoul National University. Ph.D Thesis., 142p.
  62. Qi, H., Hu, R., Su, W., Qi, L. and Feng, J. (2004). Continental hydrothermal sedimentary siliceous rock and genesis of superlarge germanium (Ge) deposit hosted in coal: a study from the Lincang Ge deposit, Yunnan, China. Sci. China Ser. D., v.47(11), p.973-984. doi: 10.1360/02yc0141
  63. Rice, C., Belkin, H., Henry, T., Zartman, R. and Kunk, M. (1996). The Pennsylvanian Fire Clay tonstein of the Appalachian basinIts distribution, biostratigraphy, and mineralogy: Discussion and reply discussion-Reply. Geol. Soc. Am. Bull., v.108(1), p.121-125. doi: 10.1130/spe294-p87
  64. Robbins, E., Zielinski, R., Otton, J., Owen, D., Schumann, R. and McKee, J. (1990). Microbially mediated fixation of uranium, sulfur, and iron in a peat-forming montane wetland, Larimer County, Colorado. USGS Research on Energy Resources-1990 Program and Abstracts: USGS Circ., v.1060, p.70-71.
  65. Robl, T. and Bland, A. (1977). Distribution of Aluminum in Shales Associated With the Major Economic Coal Seams of Eastern Kentucky. Third Coal Refuse Disposal and Utilization Symposium, 3rd, p.97.
  66. Ruppert, L., Finkelman, R., Boti, E., Milosavljevic, M., Tewalt, S., Simon, N. and Dulong, F. (1996). Origin and significance of high nickel and chromium in the Pliocene Kosovo Basin lignite, Central Yugoslavia. Int. J. Coal Geol., v.29, p.235-258. doi: 10.1016/0166-5162(95)00031-3
  67. Seredin, V. (1991). On a new type of rare earth elements' mineralization of Cenozoic coal-bearing depressions. Doklady Akademii Nauk SSSR, v.320(6), p.1446-1450.
  68. Seredin, V. (1994). The first data on abnormal Niobium content in Russian coals. Dokl. Earth Sci, p.634-636.
  69. Seredin, V. (1996). Rare earth element-bearing coals from the Russian Far East deposits. Int. J. Coal Geol., v.30(1-2), p.101-129. doi: 10.1016/0166-5162(95)00039-9
  70. Seredin, V. (1998). Rare earth mineralization in late Cenozoic explosion structures (Khankai massif, Primorskii Krai, Russia). Geol. Ore Deposits, v.40.
  71. Seredin, V. (2004). Metalliferous coals: formation conditions and outlooks for development. Coal Resources of Russia, v.6, p.452-519.
  72. Seredin, V. (2005). Rare earth elements in germanium-bearing coal seams of the Spetsugli deposit (Primor'e Region, Russia). Geol. Ore Deposits, v.47.
  73. Seredin, V. and Shpirt, M.Y. (1999). Rare earth elements in the humic substance of metalliferous coal. Lithology and Mineral Resources C/C of Litologiia I Poleznye Iskopaemye, v.34, p.244-248.
  74. Seredin, V.V. and Dai, S. (2012). Coal deposits as potential alternative sources for lanthanides and yttrium. Int. J. Coal Geol., v.94, p.67-93. doi: 10.1016/j.coal.2011.11.001
  75. Seredin, V.V. and Finkelman, R.B. (2008). Metalliferous coals: a review of the main genetic and geochemical types. Int. J. Coal Geol., v.76(4), p.253-289. doi: 10.1016/j.coal.2008.07.016
  76. Sergeev, A.C. (1997). Uranium in fossil fuel and carboniferous rocks. Introduction in Metallogeny of Fossil Fuel and Carboniferous Rocks. Sankt-Petersburg University.
  77. Shvets, V. and Boyarko, G.Y. (1999). On industrial value of rare earth and germanium in the main coal seams of Southern Yakutia. In Geology and Tectonic of Platforms and Orogenic Belts of the North-Eastern Asia, Yakutsk., v.2, p.186-189.
  78. Sozinov, N. (1966). Uranium-germanium ore in Miocene coalbearing strata. Materialy koordinatsionnogo soveta., v.2, p.55-59.
  79. Stone, R.W. (1912). Coal near the black hills Wyoming-South Dakota. U.S. Geol. Surv. Bull., v.499, p.1-66. doi: 10.3133/b499
  80. Valiev, Y.Y., Goffen, G. and Pachadzhanov, D. (2002). Gold in Jurassic coals in the mountainous framing of the Tajik Basin and its prospecting significance. Geochemistry International, v.40(1), p.96-99.
  81. Vine, J.D. (1962). Geology of uranium in coaly carbonaceous rocks. US Geol. Surv., 356p. doi: 10.3133/pp356d
  82. Ward, C.R., Spears, D., Booth, C.A., Staton, I. and Gurba, L.W. (1999). Mineral matter and trace elements in coals of the Gunnedah Basin, New South Wales, Australia. Int. J. Coal Geol., v.40(4), p.281-308. doi: 10.1016/s0166-5162(99)00006-3
  83. Zhang, W., Noble, A., Yang, X. and Honaker, R. (2020). A comprehensive review of rare earth elements recovery from coal-related materials. Minerals, v.10(5), p.451. doi: 10.3390/min10050451
  84. Zhang, W., Rezaee, M., Bhagavatula, A., Li, Y., Groppo, J. and Honaker, R. (2015). A review of the occurrence and promising recovery methods of rare earth elements from coal and coal byproducts. Int. J. Coal Prep. Util., v.35(6), p.295-330. doi: 10.1080/19392699.2015.1033097
  85. Zhao, L., Dai, S., Graham, I.T., Li, X., Liu, H., Song, X., Hower, J.C. and Zhou, Y. (2017). Cryptic sediment-hosted critical element mineralization from eastern Yunnan Province, southwestern China: Mineralogy, geochemistry, relationship to Emeishan alkaline magmatism and possible origin. Ore Geol. Rev., v.80, p.116-140. doi: 10.1016/j.oregeorev.2016.06.014
  86. Zhuang, X., Querol, X., Zeng, R., Xu, W., Alastuey, A., Lopez-Soler, A. and Plana, F. (2000). Mineralogy and geochemistry of coal from the Liupanshui mining district, Guizhou, south China. Int. J. Coal Geol., v.45(1), p.21-37. doi: 10.1016/s0166-5162(00)00019-7