Editing Fumarole (section)

== Economic resources and hazards ==
[[File:Bergelut dengan asap nan beracun.jpg|thumb|upright|Traditional [[sulfur mining]] at [[Kawah Ijen]].]]

The acidic fumes from fumaroles can break down the rock around the vents, producing brightly colored ''alteration haloes''.<ref name=PhilpottsAgue2009/> At Sulphur Banks near [[Kīlauea|Kilauea]] in Hawaii, mild alteration reduces the rock to gray to white [[opal]] and [[kaolinite]] with the original [[Texture (geology)|texture]] of the rock still discernible. Alteration begins along [[Joint (geology)|joints]] in the rock and works inwards until the entire joint block is altered. More extreme alteration (at lower [[pH]]) reduces the material to [[clay mineral]]s and [[iron oxides]] to produce red to reddish-brown [[clay]].{{sfn|Macdonald|Abbott|Peterson|1983|p=134}} The same process can produce valuable [[hydrothermal mineral deposit|hydrothermal ore deposits]] at depth.<ref name=PhilpottsAgue2009/>

Fumaroles emitting sulfurous vapors form surface deposits of sulfur-rich minerals and of [[fumarole mineral]]s. Sulfur crystals at Sulfur Banks near Kilauea can grow to {{convert|2|cm|sigfig=1|sp=us}} in length, and considerable sulfur has been deposited at Sulfur Cone within [[Mauna Loa]] caldera.<ref name=MacdonaldEtal1983/> Places in which these deposits have been mined include:

* [[Kawah Ijen]]<ref name=JakartaPost>{{cite news  |url=http://www.thejakartapost.com/news/2011/12/19/kawah-ijen-between-potential-threat.html |title=Kawah Ijen: Between potential & threat |newspaper=The Jakarta Post |date=19 December 2011}}</ref><ref>{{cite news |last1=Dukehart |first1=Coburn |title=The Struggle and Strain of Mining "Devil's Gold" |url=https://www.nationalgeographic.com/photography/article/the-struggle-and-strain-of-mining-devils-gold |archive-url=https://web.archive.org/web/20210409213710/https://www.nationalgeographic.com/photography/article/the-struggle-and-strain-of-mining-devils-gold |url-status=dead |archive-date=9 April 2021 |access-date=1 March 2022 |agency=National Geographic |date=17 November 2015}}</ref> and [[Arjuno-Welirang]],<ref>{{cite web |last1=Pfeiffer |first1=Tom |title=Welirang volcano photos |url=http://www.decadevolcano.net/photos/welirang_volcano_photos.htm |website=Volcano Discovery |access-date=1 March 2022 |date=2006}}</ref> Indonesia
* [[Purico Complex]]<ref>[http://www.volcano.si.edu/volcano.cfm?vn=355094 Global Volcanism Program, National Museum of Natural History, Smithsonian Institution]</ref> near [[San Pedro de Atacama]] in Chile
* [[Mount Tongariro]] in the central [[North Island]], New Zealand (mined by [[Māori people|Māori]] until 1950)<ref>{{cite journal |last1=Simpson |first1=Mark P. |last2=Bignall |first2=Greg |title=Undeveloped high-enthalpy geothermal fields of the Taupo Volcanic Zone, New Zealand |journal=Geothermics |date=January 2016 |volume=59 |pages=325–346 |doi=10.1016/j.geothermics.2015.08.006|bibcode=2016Geoth..59..325S }}</ref>
* [[Whakaari / White Island]] in the [[Bay of Plenty]], New Zealand (mined from the 1880s to the 1930s)<ref>{{cite web |title=Eruption on Whakaari White Island kills 10 people |url=https://nzhistory.govt.nz/page/eruption-whakaari-white-island-kills-10-people |website=nzhistory.govt.nz |access-date=26 October 2021 |language=en}}</ref><ref>{{cite web |title=Disaster at White Island |url=https://www.nzgeo.com/stories/disaster-at-white-island/ |website=New Zealand Geographic |access-date=26 October 2021 |language=en-NZ}}</ref>
* [[Sicily]], which had a near-monopoly on sulfur prior to development of the [[Frasch process]] for mining sulfur from salt domes.<ref>{{cite book |last1=Ferrara |first1=Vincenzo |title=Essays on the History of Mechanical Engineering |chapter=The Sulphur Mining Industry in Sicily |series=History of Mechanism and Machine Science |date=2016 |volume=31 |pages=111–130 |doi=10.1007/978-3-319-22680-4_8|isbn=978-3-319-22679-8 }}</ref>

Sulfur mining in Indonesia is sometimes done for low pay, by hand, without respirators or other protective equipment.<ref name=JakartaPost/>

In April 2006 fumarole emissions killed three [[Ski patrol|ski-patrol]] workers east of Chair 3 at [[Mammoth Mountain Ski Area]] in California. The workers were overpowered by an accumulation of toxic fumes (a ''[[mazuku]]'') in a crevasse they had fallen into.<ref>{{cite news |url= https://www.latimes.com/archives/la-xpm-2006-apr-09-me-mammoth9-story.html |title= How Routine Turned to Tragedy at Mammoth |date= 2006-04-09 |first1= Steve |last1= Hymon |first2= Amanda |last2= Covarrubias |access-date= 2011-05-09 |newspaper= Los Angeles Times}}
</ref><ref>{{cite journal |last1=Cantrell |first1=Lee |last2=Young |first2=Michael |title=Fatal Fall into a Volcanic Fumarole |journal=Wilderness & Environmental Medicine |date=March 2009 |volume=20 |issue=1 |pages=77–79 |doi=10.1580/08-WEME-CR-199.1|pmid=19364170 |s2cid=207182190 |doi-access=free }}</ref>