Bauxite

{{short description|Sedimentary rock rich in aluminium}} {{Use American English |date=June 2024}} {{Use mdy dates |date=June 2024}} {{about|the ore|the town in Arkansas|Bauxite, Arkansas}} thumb|Reddish-brown bauxite [[File:BauxiteUSGOV.jpg|thumb|Bauxite with US penny for comparison]] [[File:Qemscan pisoliths.png|thumb|QEMSCAN mineral maps of bauxite ore-forming pisoliths]]

'''Bauxite''' ({{IPAc-en|ˈ|b|ɔː|k|s|aɪ|t|audio=LL-Q1860 (eng)-Naomi Persephone Amethyst (NaomiAmethyst)-Bauxite.wav}}) is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite ({{chem2|Al(OH)3}}), boehmite (γ-AlO(OH)), and diaspore (α-AlO(OH)), mixed with the two iron oxides goethite (FeO(OH)) and hematite ({{chem2|Fe2O3}}), the aluminium clay mineral kaolinite ({{chem2|Al2Si2O5(OH)4}}) and small amounts of anatase ({{chem2|TiO2}}) and ilmenite ({{chem2|FeTiO3}} or {{chem2|FeO*TiO2}}).<ref>{{cite book | author=Geological Survey (U.S.) | title=Geological Survey Professional Paper | publisher=U.S. Government Printing Office | issue=v. 1076, pt. 2 | year=1986 | url=https://books.google.com/books?id=bMVUAAAAYAAJ&pg=SL2-PA20 | page=2-PA20}}</ref><ref>{{cite web | url=http://www.clays.org/GLOSSARY/Clay_Glossary.htm | title=The Clay Minerals Society Glossary for Clay Science Project | url-status=dead | archive-url=https://web.archive.org/web/20160416024036/http://www.clays.org/GLOSSARY/Clay_Glossary.htm | archive-date=2016-04-16}}</ref> Bauxite appears dull in luster and is reddish-brown, white, or tan.<ref>{{cite web | title=Aluminum | publisher=Minerals Education Coalition | url=https://mineralseducationcoalition.org/minerals-database/aluminum/#:~:text=Aluminum%20is%20the%20most%20abundant,gibbsite%2C%20boehmite%2C%20and%20diaspore.&text=Because%20it%20is%20a%20mixture,a%20rock%2C%20not%20a%20mineral}}</ref>

The origin of the name stems from its discovery in 1821 by the French geologist Pierre Berthier near the village of Les Baux in Provence, Southern France.<ref>P. Berthier (1821) [https://books.google.com/books?id=53wkLqfF6tQC&pg=PA531 "Analyse de l'alumine hydratée des Beaux, département des Bouches-du-Rhóne"] (Analysis of hydrated alumina from Les Beaux, department of the Mouths-of-the-Rhone), ''Annales des mines'', 1st series, '''6''' : 531–534. Notes: * In 1847, in the cumulative index of volume 3 of his series, ''Traité de minéralogie'', French mineralogist Armand Dufrénoy listed the hydrated alumina from Les Beaux as "beauxite". (See: A. Dufrénoy, ''Traité de minéralogie'', volume 3 (Paris, France: Carilian-Goeury et Vor Dalmont, 1847), [https://books.google.com/books?id=XxwOAAAAQAAJ&pg=PA799 p. 799.]) * In 1861, H. Sainte-Claire Deville credits Berthier with naming "bauxite", on p. 309, "Chapitre 1. Minerais alumineux ou bauxite" of: H. Sainte-Claire Deville (1861) [http://babel.hathitrust.org/cgi/pt?id=hvd.hx3dz6;view=1up;seq=321 "De la présence du vanadium dans un minerai alumineux du midi de la France. Études analytiques sur les matières alumineuses."] {{Webarchive|url=https://web.archive.org/web/20210427142748/https://babel.hathitrust.org/cgi/pt?id=hvd.hx3dz6;view=1up;seq=321 |date=April 27, 2021 }} (On the presence of vanadium in an alumina mineral from the Midi of France. Analytical studies of aluminous substances.), ''Annales de Chimie et de Physique'', 3rd series, '''61''' : 309–342.</ref><ref>{{Cite web |last=Burgess |first=N. |date=October 26, 2015 |title=March 23, 1821: Bauxite Discovered |url=https://www.earthmagazine.org/article/march-23-1821-bauxite-discovered/ |access-date=2021-07-31 |publisher=Earth}}</ref>

== Formation == thumb|Bauxite with core of unweathered rock Numerous classification schemes have been proposed for bauxite but, {{As of|1982|lc=y}}, there was no general agreement.<ref name="BatdossyKarst1982">{{cite book | title=Karst Bauxites | publisher=Elsevier | author=Bárdossy, G. | year=1982 | location=Amsterdam | page=16 | isbn=978-0-444-99727-2}}</ref>

Vadász (1951) distinguished lateritic bauxites (silicate bauxites) from karst bauxite ores (carbonate bauxites):<ref name="BatdossyKarst1982"/> * The carbonate bauxites occur predominantly in Europe, Guyana, Suriname, and Jamaica above carbonate rocks (limestone and dolomite), where they were formed by lateritic weathering and residual accumulation of intercalated clay layers – dispersed clays which were concentrated as the enclosing limestones gradually dissolved during chemical weathering. * The lateritic bauxites are found mostly in the countries of the tropics. They were formed by lateritization of various silicate rocks such as granite, gneiss, basalt, syenite, and shale. In comparison with the iron-rich laterites, the formation of bauxites depends even more on intense weathering conditions in a location with very good drainage. This enables the dissolution of the kaolinite and the precipitation of the gibbsite. Zones with highest aluminium content are frequently located below a ferruginous surface layer. The aluminium hydroxide in the lateritic bauxite deposits is almost exclusively gibbsite.

In the case of Jamaica, recent analysis of the soils showed elevated levels of cadmium, suggesting that the bauxite originates from Miocene volcanic ash deposits from episodes of significant volcanism in Central America.<ref>{{Cite journal |last1=Muhs |first1=Daniel R. |last2=Budahn |first2=James R. |date=2009 |title=Geochemical evidence for African dust and volcanic ash inputs to terra rossa soils on carbonate reef terraces, northern Jamaica, West Indies |doi=10.1016/j.quaint.2007.10.026 |journal=Quaternary International |volume=196 |issue=1–2 |page=15 |bibcode=2009QuInt.196...13M }}</ref>

==Production and reserves== {{see also|List of countries by mineral production}}

thumb|upright=1.8|World bauxite production in 2005

[[File:Weipa-bauxite-mine.jpg|thumb|upright=1.3|One of the world's largest bauxite mines in Weipa, in northern Queensland, Australia]]

Guinea is the largest producer of bauxite, followed by Australia and China.<ref name="BauxiteAlumina2024">{{Cite web |last= |first= |date=April 2025|title=Bauxite and Alumina 2025 Annual Publication |url=https://pubs.usgs.gov/periodicals/mcs2025/mcs2025-bauxite-alumina.pdf |archive-url= |archive-date= |access-date=26 April 2025 |website=U.S. Geological Survey}}</ref> Bauxite is usually strip mined because it is almost always found near the surface of the terrain, with little or no overburden. Increased aluminium recycling, which requires less electric power than producing aluminium from ores, may considerably extend the world's bauxite reserves.

==Aluminium production== {{See also | Aluminium#Production and refinement}} [[File:CaboRojoDRBauxite.jpg|thumb|upright=1.3|Bauxite being loaded at Cabo Rojo, Dominican Republic, to be shipped elsewhere for processing; 2007]] thumb|Bauxite being digested by washing with a hot solution of sodium hydroxide at {{convert|175|C}} under pressure at National Aluminium Company, Nalconagar, India {{As of|2010}}, approximately 70% to 80% of the world's dry bauxite production is processed first into alumina and then into aluminium by electrolysis.<ref>{{Cite web|url=http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/periodictable/electrolysisrev3.shtml|title=BBC – GCSE Bitesize: Making aluminium|language=en-GB|access-date=2018-04-01|archive-url=https://web.archive.org/web/20180225224144/http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/periodictable/electrolysisrev3.shtml|archive-date=2018-02-25|url-status=dead}}</ref> Bauxite rocks are typically classified according to their intended commercial application: metallurgical, abrasive, cement, chemical, and refractory.<ref>{{Cite web |last=Australia |first=Geoscience |date=2023-12-19 |title=Bauxite |url=https://www.ga.gov.au/scientific-topics/minerals/mineral-resources-and-advice/australian-resource-reviews/bauxite |access-date=2024-03-06 |website=Geoscience Australia |language=en}}</ref><ref>{{Cite web |title=Bauxite and Alumina Statistics and Information {{!}} U.S. Geological Survey |url=https://www.usgs.gov/centers/national-minerals-information-center/bauxite-and-alumina-statistics-and-information |access-date=2024-02-08 |website=www.usgs.gov}}</ref>

Bauxite ore is usually heated in a pressure vessel along with a sodium hydroxide solution at a temperature of {{cvt|150|to|200|°C|-1|}}. At these temperatures, the aluminium is dissolved as sodium aluminate (the Bayer process). The aluminium compounds in the bauxite may be present as gibbsite (Al(OH)3), boehmite (AlOOH) or diaspore (AlOOH); the different forms of the aluminium component will dictate the extraction conditions. The undissolved waste, bauxite tailings, after the aluminium compounds are extracted contains iron oxides, silica, calcia, titania and some un-reacted alumina. After separation of the residue by filtering, pure gibbsite is precipitated when the liquid is cooled, and then seeded with fine-grained aluminium hydroxide. The gibbsite is usually converted into aluminium oxide, Al2O3, by heating in rotary kilns or fluid flash calciners to a temperature in excess of {{cvt|1000|°C||||}}. This aluminium oxide is dissolved at a temperature of about {{cvt|960|°C||||}} in molten cryolite. Next, this molten substance can yield metallic aluminium by passing an electric current through it in the process of electrolysis, which is called the Hall–Héroult process, named after its American and French discoverers.

Prior to the invention of this process, and prior to the Deville process, aluminium ore was refined by heating ore along with elemental sodium or potassium in a vacuum. The method was complicated and consumed materials that were themselves expensive at that time. This made early elemental aluminium more expensive than gold.<ref>{{cite web |url=http://www.worldwidewords.org/articles/aluminium.htm |title=Aluminium versus aluminum |author=Michael Quinion |publisher=Worldwidewords.org |date=2006-01-23 |access-date=2011-12-19 |archive-date=October 23, 2019 |archive-url=https://web.archive.org/web/20191023061812/http://www.worldwidewords.org/articles/aluminium.htm |url-status=live }}</ref>

==Maritime safety== As a bulk cargo, bauxite is a Group A cargo that may liquefy if excessively moist.<ref>{{cite web|title=IMSBC CODE GROUP A CARGOES|url=https://www.bimco.org/cargo/solid-bulk-cargo/imsbc-code/imsbc-code-group-a-cargoes|access-date=21 November 2021|publisher=Baltic and International Maritime Council}}</ref> Liquefaction and the free surface effect can cause the cargo to shift rapidly inside the hold and make the ship unstable, potentially sinking the ship. One vessel suspected to have been sunk in this way was the MS ''Bulk Jupiter'' in 2015.<ref>{{cite web|title=Bulk Jupiter sinking: A stark reminder of bauxite cargo risks|url=https://safety4sea.com/cm-bulk-jupiter-sinking-a-stark-reminder-of-bauxite-cargo-risks/|website=Safety4Sea|date=September 20, 2019|access-date=21 November 2021}}</ref> One method which can demonstrate this effect is the "can test", in which a sample of the material is placed in a cylindrical can and struck against a surface many times.<ref>{{cite web|title=What a Can Test Can Do|url=https://www.nepia.com/articles/what-a-can-test-can-do/|date=8 February 2021|access-date=21 November 2021|archive-date=February 17, 2022|archive-url=https://web.archive.org/web/20220217155413/https://www.nepia.com/articles/what-a-can-test-can-do/|url-status=live}}</ref> If a moist slurry forms in the can, then there is a likelihood for the cargo to liquefy; although conversely, even if the sample remains dry it does not conclusively prove that it will remain that way, or that it is safe for loading.

==Source of gallium== Bauxite is the main source of the rare metal gallium.<ref>{{cite web|url=https://pubs.usgs.gov/of/2013/1272/pdf/ofr2013-1272.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://pubs.usgs.gov/of/2013/1272/pdf/ofr2013-1272.pdf |archive-date=2022-10-09 |url-status=live |title=Compilation of Gallium Resource Data for Bauxite Deposits |first1=R.F. |last1=Schulte |first2=N.K. |last2=Foley |year=2014 |publisher=USGS |access-date=2017-12-01}}</ref>

During the processing of bauxite to alumina in the Bayer process, gallium accumulates in the sodium hydroxide liquor. From this it can be extracted by a variety of methods. The most recent is the use of ion-exchange resin.<ref name="Frenzel-2016">{{Cite journal|last1=Frenzel|first1=Max|last2=Ketris|first2=Marina P.|last3=Seifert|first3=Thomas|last4=Gutzmer|first4=Jens|date=March 2016|title=On the current and future availability of gallium|journal=Resources Policy|volume=47|pages=38–50|doi=10.1016/j.resourpol.2015.11.005|bibcode=2016RePol..47...38F }}</ref> Achievable extraction efficiencies critically depend on the original concentration in the feed bauxite. At a typical feed concentration of 50 ppm, about 15 percent of the contained gallium is extractable.<ref name="Frenzel-2016" /> The remainder reports to the red mud and aluminium hydroxide streams.<ref>{{Cite journal|last=Moskalyk|first=R. R.|date=2003|title=Gallium: the backbone of the electronics industry|journal=Minerals Engineering|volume=16|issue=10|pages=921–929|doi=10.1016/j.mineng.2003.08.003|bibcode=2003MiEng..16..921M }}</ref>

Bauxite is also a potential source for vanadium.<ref>{{Cite journal |last1=Cusack |first1=Patricia B. |last2=Courtney |first2=Ronan |last3=Healy |first3=Mark G. |last4=O'Donoghue |first4=Lisa |last5=Ujaczki |first5=Eva |date=2019 |title=An evaluation of the general composition and critical raw material content of bauxite residue in a storage area over a twelve-year period |doi=10.1016/j.jclepro.2018.10.083 |journal=Journal of Cleaner Production |volume=208 |issue=20 |pages=393 |bibcode=2019JCPro.208..393C |hdl=10379/14624 |via=Elsevier Science Direct|hdl-access=free }}</ref>

== Socio-ecological impacts == thumb|Mineração Rio do Norte (MRN) Bauxite Mine The social and environmental impacts of bauxite extraction are well documented. Most of the world's bauxite deposits can be found within {{convert|1|to|20|m}} of the earths surface.<ref name="Ky-2017">{{cite journal | last1=Ky | first1=Lee | last2=Ly | first2=Ho | last3=Kh | first3=Tan | last4=Yy | first4=Tham | last5=Sp | first5=Ling | last6=Am | first6=Qureshi | last7=T | first7=Ponnudurai | last8=R | first8=Nordin | title=Environmental and Occupational Health Impact of Bauxite Mining in Malaysia: A Review | journal=IIUM Medical Journal Malaysia | volume=16 | issue=2 | date=2017-12-01 | issn=2735-2285 | doi=10.31436/imjm.v16i2.346| doi-access=free }}</ref><ref name="Annandale-2021">{{cite journal | last1=Annandale | first1=Mark | last2=Meadows | first2=John | last3=Erskine | first3=Peter | title=Indigenous forest livelihoods and bauxite mining: A case-study from northern Australia | journal=Journal of Environmental Management | volume=294 | date=2021 | doi=10.1016/j.jenvman.2021.113014 | article-number=113014| pmid=34144319 | bibcode=2021JEnvM.29413014A }}</ref> Strip mining is the most common technique used for extracting shallow bauxite.<ref name="Annandale-2021" /> This process involves removing the vegetation, top soil, and overburden to expose the bauxite ore.<ref name="Annandale-2021" /> The overlying soil is typically stockpiled in order to rehabilitate the mine once operations have finished.<ref name="Annandale-2021" /> During the strip mining process, the biodiversity and habitat once present in the area is completely lost and the hydrological and soil characteristics in the region are permanently altered.<ref name="Annandale-2021" /> Other environmental impacts of bauxite mining include soil degradation, air pollution, and water pollution.<ref name="Ky-2017" />

=== Red mud === {{Main|Red mud}} Red mud is a highly alkaline sludge, with a high pH around 13, that is a byproduct of the Bayer process.<ref name="Morris-2013">{{cite thesis| last=Morris | first=Jason | title=The Vietnamese Bauxite Mining Controversy: the Emergence of a New Oppositional Politics |id={{ProQuest|}} | url=https://www.proquest.com/openview/8a1c0a23799a8e21aac0251e164580cd/1?pq-origsite=gscholar&cbl=18750 |publisher=University of California, Berkeley |year=2013 |degree=PhD}}</ref> It contains several compounds such as sodium aluminosilicate, calcium titanate, monohydrate aluminium, and trihydrate aluminium that do not break down in nature. When improperly stored, red mud can contaminate soil and water, which can result in local extinction of all life. Red mud was responsible for killing all life in the Marcal River in Hungary after a spill occurred in 2010. When red mud dries, it turns into dust that can cause lung disease, cancer and birth defects.<ref name="Morris-2013" />

=== Conflicts === In the tropical regions of Asia, central Africa, South America and northern Australia, there has been an increase of bauxite mines on traditional and indigenous lands.<ref name="Annandale-2021" /> This has resulted in a number of negative social impacts on local and indigenous peoples.<ref name="Dibattista-2023">{{cite journal | last1=Dibattista | first1=Ilaria | last2=Camara | first2=Abdoul Rachid | last3=Molderez | first3=Ingrid | last4=Benassai | first4=Edoardo Maria | last5=Palozza | first5=Francesco | title=Socio-environmental impact of mining activities in Guinea: The case of bauxite extraction in the region of Boké | journal=Journal of Cleaner Production | volume=387 | date=2023 | doi=10.1016/j.jclepro.2022.135720 | article-number=135720| bibcode=2023JCPro.38735720D | url=https://lirias.kuleuven.be/handle/20.500.12942/710098 | url-access=subscription }}</ref> In the Boké Region of Guinea, there has been a significant increase in bauxite mining pressure on the local population. This has resulted in potable water issues, air pollution, food contamination, and land expropriation disputes due to improper compensation.<ref name="Dibattista-2023" />

Bauxite mining has led to protests, civil unrest, and violent conflicts in Guinea, Ghana, Vietnam, and India.<ref name="Morris-2013" />

=== Guinea === Guinea has a long history of mining related conflicts between communities and mining companies.{{cn|date=June 2024}} Between 2015 and 2018, new bauxite mining operations in the Boké Region of Guinea have caused in 35 conflicts which include movements of revolts and road blockades. These conflicts have resulted in the loss of human life, the destruction of heavy machinery, and damage to government buildings.{{cn|date=June 2024}}

=== Ghana === The Atewa range in Ghana, classified as an ecologically important forest reserve with an area of {{convert|17,400|ha}}, has been is a recent site of conflict and controversy surrounding bauxite mining.<ref name="Purwins-2022">{{cite journal | last=Purwins | first=Sebastian | title=Bauxite mining at Atewa Forest Reserve, Ghana: a political ecology of a conservation-exploitation conflict | journal=GeoJournal | volume=87 | issue=2 | date=2022 | issn=0343-2521 | pmid=32989342 | pmc=7512217 | doi=10.1007/s10708-020-10303-3 | pages=1085–1097| bibcode=2022GeoJo..87.1085P }}</ref> The forest reserve is one of the only two upland evergreen forests in Ghana, and makes up a significant portion of the remaining 20% of forested habitat left in Ghana. The Atewa range falls under the jurisdiction of Akyem Abuakwa Traditional Area and is overseen by the king known as Okyenhene.<ref name="Purwins-2022" /> In 2013, an NGO called A Rocha Ghana held a summit with the forestry and water resource commission, the minister of lands, the minister of the environment, and other important stakeholders. They came to the conclusion that no future government should mine bauxite in the region because the reserve is environmentally and culturally significant.<ref name="Purwins-2022" />

In 2016, the government along with NGO's began the process of upgrading the reserved to a national park. However, that year an election took place, and before it became official, the newly elected National Patriotic Party (NPP) rejected the plan.<ref name="Purwins-2022" /> In 2017, the government of Ghana signed a Memorandum of Understanding with China to develop new bauxite mining infrastructure in Ghana. Although there was no official plan to mine the Atewa Forest Reserve, tensions between local communities, NGO and the government began to rise. In 2019, tensions began to reach a peak when the government presented the ''Ghana Integrated Bauxite and Aluminium Development Authority Act'' that would create the legal framework required to develop and establish an integrated bauxite industry.<ref name="Purwins-2022" /> In May of that year, the government began drilling deep holes in the reserve.

These actions sparked several protests, including a {{convert|95|km|adj=on}} march from the reserve to the presidential palace, an informational billboard campaign led by A Rocha Ghana, and a youth march.<ref name="Purwins-2022" /> In 2020, A Rocha Ghana also sued the government over the drilling in the reserve after they failed to provide a statement explaining their actions.<ref name="Purwins-2022" />

=== Vietnam === In early 2009, the Vietnamese Government proposed a plan to mine remote regions of the central highlands.<ref name="Morris-2013" /> This proposal was highly controversial and sparked a nationwide debate and the most significant domestic conflict since the Vietnam War. Government scientists, journalists, religious leaders, retired high level state officials, and General Võ Nguyên Giáp, the military leader of anti-colonial revolution, were among the many people across Vietnamese society who opposed the governments plans.<ref name="Morris-2013" /> In an attempt to stop the spread of information across the globe, the government banned domestic reporters from reporting on bauxite mining. However, reporters turned to Vietnamese language websites and blogs where the reporting and discussion continued.

On April 12, 2009, several well-respected Vietnamese scholars started a petition against the mining of bauxite that was signed by 135 accomplished and well known "Intellectuals".<ref name="Morris-2013" /> This petition helped unite the scattered anti-bauxite movement into a unified opposition against the state. These acts of governmental defiance were met with repressive state actions. Many domestic online reporters were arrested, and legislative action was taken to repress scientific research.<ref name="Morris-2013" />

=== India === Most of India's bauxite ore reserves, which are among the top ten largest in the world, are located on tribal land.<ref name="Padel-2015">{{cite book |last=Padel |first=F. |year=2015 |chapter=The Bauxite-Aluminium Industry and India's Adivasis |title=Mining, the Aluminium Industry and Indigenous Peoples |pages=101–112 |url=https://www.forestpeoples.org/sites/default/files/news/2015/11/Mining%2C%20the%20Aluminium%20Industry%20and%20Indigenous%20Peoples.pdf#page=107}}</ref> These tribal lands are densely populated and home to over 100 million Indigenous Indian peoples. The mountain summits located on these lands act as a source of water and greatly contribute to the regions fertility.<ref name="Padel-2015" /> The Indian bauxite industry is interested in developing this land for aluminium production, which poses great risk to the terrestrial and aquatic ecosystems. Historically, the Indigenous peoples living on these lands have shown resistance to development, and oppose any new bauxite mining projects in the area. This has led to violent conflicts between Indigenous communities and police.<ref name="Padel-2015" /> On December 16, 2000, police killed three Indigenous protestors and wounded over a dozen more during a protest over a bauxite project in the Rayagada district of Odisha.<ref name="Padel-2015" />

==References== {{Reflist}}

==Further reading== * Bárdossy, G. (1982): ''Karst Bauxites: Bauxite deposits on carbonate rocks''. Elsevier Sci. Publ. 441 p. * Bárdossy, G. and Aleva, G.J.J. (1990): ''Lateritic Bauxites''. Developments in Economic Geology 27, Elsevier Sci. Publ. 624 p. {{ISBN|0-444-98811-4}} * Grant, C.; Lalor, G. and Vutchkov, M. (2005) ''Comparison of bauxites from Jamaica, the Dominican Republic and Suriname''. Journal of Radioanalytical and Nuclear Chemistry p. 385–388 Vol.266, No.3 * Hanilçi, N. (2013). ''Geological and geochemical evolution of the Bolkardaği bauxite deposits, Karaman, Turkey: Transformation from shale to bauxite''. Journal of Geochemical Exploration

==External links== {{commons category|Bauxite}} * [https://minerals.usgs.gov/minerals/pubs/commodity/bauxite/ USGS Minerals Information: Bauxite] {{Webarchive|url=https://web.archive.org/web/20090506220703/http://minerals.usgs.gov/minerals/pubs/commodity/bauxite/ |date=May 6, 2009 }} * [https://web.archive.org/web/20051003232659/http://www.mii.org/Minerals/photoal.html Mineral Information Institute] * {{Cite NIE|wstitle=Bauxite |year=1905 |short=x}} * usgs.gov (Mineral Commodity Summaries 2025): [https://pubs.usgs.gov/periodicals/mcs2025/mcs2025.pdf#page=42 Bauxite]

Category:Sedimentary rocks Category:Aluminium minerals Category:Bauxite mining Category:Articles containing video clips Category:Regolith Category:Weathering