Editing Inco Superstack

{{short description|Second-tallest freestanding chimney}}
{{Use mdy dates|date=June 2020}}
{{Use Canadian English|date=October 2024}}
{{Infobox building
| name                = Inco Superstack
| image               = Inco Superstack.JPG
| image_size          = 250px
| image_alt           = <!-- or | alt = -->
| image_caption       = The Vale-Inco (former Inco) Superstack at the Inco Copper Cliff smelter
| map_type            =
| map_alt             =
| map_caption         =
| map_size            =
| map_dot_label       =
| map_dot_mark        =
| relief              =
| alternate_names     = Vale Superstack
| status              =
| cancelled           =
| topped_out          =
| building_type       = Chimney
| location            =
| address             =
| location_city       = [[Greater Sudbury]]
| location_country    = Canada
| coordinates         = {{coord|46|28|48.23|N|81|3|23.43|W|display=inline,title}}
| altitude            =
| current_tenants     =
| namesake            =
| groundbreaking_date =
| start_date          = 1970
| stop_date           =
| est_completion      =
| topped_out_date     =
| completion_date     = 1972
| opened_date         =
| renovation_date     =
| closing_date        =
| demolition_date     = <!-- or | destruction_date    = -->
| cost                = $25 million ($160 million inflation adjusted)
| ren_cost            =
| owner               = [[Vale Limited]]
| height              = {{convert|381|m|ft|abbr=on}}
| diameter            = at base: {{convert|35|m|ft|abbr=on}}<br/>at top: {{convert|16|m|ft|abbr=on}}
| circumference       =
| weight              =
| other_dimensions    =
| structural_system   =
| material            = Reinforced concrete with stainless steel liner
| size                =
| architect           =
| architecture_firm   =
| developer           =
| engineer            =
| structural_engineer =
| main_contractor     =
| designations        =
| known_for           =
| website             = <!-- {{URL|example.com}} -->
| references          = <ref name=facts/>
| footnotes           =
| highest_prev        = [[Mitchell Power Plant]]
| highest_next        = [[Ekibastuz GRES-2 Power Station]]
| highest_start       = 1971
| highest_end         = 1987
| highest_region      = the world
| highest_reflabel    =
}}

The '''Inco Superstack''' in [[Greater Sudbury|Sudbury]], [[Ontario]], with a height of {{convert|381|m|ft}}, is the tallest [[chimney]] in [[Canada]] and in the [[Western Hemisphere]] and the [[List of chimneys|second-tallest]] freestanding chimney in the world, after the [[Ekibastuz GRES-2 Power Station]], in [[Kazakhstan]]. It is also the second-tallest freestanding structure of any type in Canada, behind the [[CN Tower]] but ahead of [[First Canadian Place]]. As of 2023, it is the [[List of tallest freestanding structures in the world|51st-tallest freestanding structure]] in the world. The Superstack is located on top of the largest nickel [[smelting]] operation in the world at [[Vale Limited|Vale]]'s [[Copper Cliff, Ontario|Copper Cliff]] processing facility in the city of Greater Sudbury.

In 2018, Vale announced that the stack would be decommissioned and dismantled, beginning in 2020.<ref>[https://www.cbc.ca/news/canada/sudbury/superstack-demolition-begins-1.4829643 "Superstack dismantling will begin in 2020, Vale says"]. [[CBCS-FM|CBC Northern Ontario]], September 19, 2018.</ref> Two new, smaller stacks were constructed under the company's Clean Atmospheric Emissions Reduction Project.<ref>Molly Frommer, [https://northernontario.ctvnews.ca/two-new-smaller-stacks-are-ready-decommissioning-of-sudbury-s-superstack-about-to-begin-1.5100192 "Two new smaller stacks are ready, decommissioning of Sudbury's Superstack about to begin"]. [[CTV Northern Ontario]], September 10, 2020.</ref> In July 2020, Vale announced that the Superstack had been officially taken out of service but would remain operational in standby mode for two more months as a backup in the event of a malfunction in the new system,<ref name=operational>[https://www.northernontariobusiness.com/regional-news/sudbury/sudburys-iconic-superstack-operational-no-more-2597116 "Sudbury's iconic Superstack operational no more"]. ''[[Northern Ontario Business]]'', July 28, 2020.</ref> and the dismantling of the Superstack would then begin.<ref>Lindsay Kelly, [https://www.northernontariobusiness.com/regional-news/sudbury/slow-process-of-demolition-to-start-on-vales-superstack-2598483 "Slow process of demolition to start on Vale's Superstack"]. ''[[Northern Ontario Business]]'', July 29, 2020.</ref> Although some have called for the stack to be left in place as a tourist attraction,<ref>Judith Van Boxel, [https://www.thesudburystar.com/opinion/columnists/column-why-tear-down-the-superstack-turn-it-into-a-tourist-attraction "Column: Why tear down the Superstack? Turn it into a tourist attraction"]. ''[[Sudbury Star]]'', May 17, 2023.</ref> in September 2024, Vale announced an updated plan, which will see the stack dismantled by 2029.<ref>[https://www.northernontariobusiness.com/industry-news/mining/sudburys-superstack-slated-for-demolition-by-2029-9474247 "Sudbury's Superstack slated for demolition by 2029"]. ''[[Northern Ontario Business]]'', September 4, 2024.</ref>

In addition to further reducing [[sulphur dioxide]] emissions by 85 per cent, the decommissioning of the stack was expected to cut the complex's [[natural gas]] consumption in half.<ref name=operational/>

==History==
The Superstack was built by Inco Limited (and later purchased by [[Vale Limited|Vale]]) at an estimated cost of 25 million dollars. Construction on the structure was underway during the [[Sudbury tornado]] of August 20, 1970; the structure swayed heavily in the wind but remained standing and suffered only minor damage.<ref name=torstar1>"90 mile winds smash Sudbury area". ''[[Toronto Star]]'', August 20, 1970. p. 1.</ref> Six workers were on top of the construction platform when the storm hit, all of whom survived.<ref name="torstar1" /> The same day was the final day of construction on the stack, with the construction fully completed by the evening of August 21, 1970.<ref>"Smokestack resisted gale to become world's tallest". ''[[Toronto Star]]'', August 22, 1970. p. D3.</ref>

The stack entered into full operation in 1972.<ref name=facts>{{cite web|title=Vale's Iconic Superstack: History and Key Facts|url=http://www.vale.com/canada/EN/aboutvale/communities/sudbury/Pages/Superstack%20History%20Fact%20Sheet_FINAL.pdf|access-date=September 20, 2020|archive-date=July 18, 2021|archive-url=https://web.archive.org/web/20210718142116/http://www.vale.com/canada/EN/aboutvale/communities/sudbury/Pages/Superstack%20History%20Fact%20Sheet_FINAL.pdf|url-status=dead}}</ref> From the date of its completion until the [[Ekibastuz GRES-2]] chimney was constructed in 1987 in [[Kazakhstan]],<ref>{{cite web |title=GRES-2 Chimney (Ekibastuz, 1987) |url=https://structurae.net/en/structures/gres-2-chimney |website=structurae.net |publisher=Structurae |access-date=28 December 2020 |language=en}}</ref> it was the world's tallest smokestack. Between 1972 and 1975, it was the tallest freestanding structure in [[Canada]].

[[File:Blackened rocks in Sudbury, Ontario.JPG|thumb|left|Blackened rocks in 2012]]
Prior to the construction of the Superstack, the waste gases had contributed to severe local ecological damage. The Copper Cliff smelter was already home to some of the world's tallest stacks, including two {{convert|500|ft|abbr=on}} chimneys constructed in 1928-29 and 1936.<ref>[http://www.sudburymuseums.ca/triangle/data/INCOTriangle-19621201.pdf INCO Triangle, December 1962, pp. 6–7, 14.]</ref> However, they proved to be insufficient and were compounded by open coke beds in the early-to-mid-20th century and by logging for fuel, which inevitably caused a near-total loss of native vegetation. Of particular interest to geologists are the now-exposed rocky outcrops, which have been permanently stained charcoal black by the pollution wafting over the decades from the roasting yards and then by the [[acid rain]] in a layer which penetrates up to three inches into the once pink-grey [[granite]].

The Superstack was built to disperse [[sulfur|sulphur]] gases and other byproducts of the smelting process away from the city of Sudbury. It did so by placing the gases high in the air, where they normally blew right past the city on the [[prevailing winds]]. As a result, the gases could be detected in the atmosphere around Greater Sudbury in a {{convert|240|km|mi}} radius of the Inco plant. During the 1970s and 80s, the sulphur dioxide plume formed a permanent, opaque, cloud-like formation running across the entire horizon as seen from a distance. Periodic [[inversion (meteorology)|inversions]] would cause the plume to fall into the city.{{cn|date=October 2020}}

Construction of the Superstack was followed by an environmental reclamation project, which included rehabilitation of existing landscapes and selected water bodies such as [[Lake Ramsey]]. An ambitious regreening plan saw over three million new trees planted within the Greater Sudbury area. In 1992, Inco and the city were given an award by the United Nations in honour of their environmental rehabilitation programmes.{{citation needed|date=March 2023}}

On November 3, 2014, Vale announced that it might decide to stop using the stack after a $1 billion project to reduce emissions by 85% that negates the need for the stack. If no other use for it is found, Vale might decommission the Superstack, demolish it, and replace it with a much smaller chimney.<ref>{{cite news|author1=Jonathan Migneault|title=Vale examines Superstack's future|url=http://www.northernlife.ca/news/localNews/2014/11/03-superstack-sudbury.aspx|newspaper=[[Northern Life (newspaper)|Northern Life]]|access-date=November 4, 2014|date=November 3, 2014}}</ref> In 2017, Vale announced plans to decommission the Superstack upon the construction of two smaller, more energy efficient stacks.<ref>{{Cite web |url=http://www.cbc.ca/news/canada/sudbury/vale-announces-superstack-done-1.3949500 |title=Superstack to be decommissioned, but no immediate plans for demolition |date=January 24, 2017 |website=cbc.ca |access-date=January 25, 2017}}</ref><ref>{{Cite press release |title=Continuous Improvement: The Superstack to be taken out of service |url=http://www.vale.com/canada/EN/aboutvale/communities/sudbury/Pages/superstack.aspx}}</ref> On July 28, 2020, Vale updated that news and stated that the Superstack at its Copper Cliff Complex had been taken out of service. It would remain on "hot standby" for about two months while the replacement flue connections were tested, but it would then be demolished over the years.<ref>{{Cite news |date=July 30, 2020 |title=Sudbury's iconic Superstack no longer operational |url=https://www.timminstoday.com/local-news/sudburys-iconic-superstack-no-longer-operational-2599596 |access-date=July 31, 2020 |work=TimminsToday}}</ref>

==Emissions==
[[Image:Sudbury sunset.JPG|thumb|250px|The Inco Superstack dominates the Sudbury skyline.]]
While the Superstack lowered the ground-level pollution in the city, it has dispersed [[sulphur dioxide]], and [[nitrogen dioxide]] gases over a much larger area. Though not the single source of [[Freshwater acidification|lake acidification]], it appears the heavily industrialized [[Ohio Valley]] has contributed to the ecological problem of lakes as far north as northern Ontario. Research from data gleaned up to the late 1980s demonstrated acid rain to have affected the biology of some 7,000 lakes.

Prior to Vale's purchase of Inco, a major construction effort by Inco in the early 1990s dramatically scrubbed waste gases before pumping them up the Superstack. The upgrades were completed in 1994 and emissions have since been much reduced.<ref>{{Cite web |url=http://www.inco-sudbury-airquality.com/SO2Emissions.htm |title=Process Overview<!-- Bot generated title --> |access-date=March 14, 2007 |archive-url=https://web.archive.org/web/20070701043702/http://www.inco-sudbury-airquality.com/SO2Emissions.htm |archive-date=July 1, 2007 |url-status=usurped }}</ref> By comparison to the plume prior to installation, the plume now disperses quite rapidly and is often see-through even at the stack site.

Emissions reductions and increases in [[thermal efficiency]] have reached the point that [[Stack effect|natural draught]] is no longer sufficient to draw flue gas up the stack and necessitate the use of induced draught fans and/or reheating of the flue gas using natural gas burners.<ref>[http://www.northernontariobusiness.com/Industry-News/mining/CVRD-Inco-plugs-sulphur-dioxide-holes.aspx Northern Ontario Business]</ref>

As well as SO<sub>2</sub> emissions, Inco's Superstack has had very high [[arsenic]], [[nickel]], and [[lead]] emissions to the atmosphere. In 1998, Inco emitted 146.7 tonnes of lead from Copper Cliff while producing 238,500 tonnes of nickel-copper matte. That is 150 times more lead emission than would be permitted by a US EPA-regulated lead smelter producing 238,500 tonnes of lead.<ref>{{Cite web |url=http://www.pollutionprobe.org/old_files/publications/Smelter%20Report.pdf |title=Pollution Probe - Sulphur Dioxide and Toxic Metal Emissions from Smelters in Ontario |page=14 |access-date=August 23, 2012 |archive-url=https://web.archive.org/web/20140109050614/http://www.pollutionprobe.org/old_files/publications/Smelter%20Report.pdf |archive-date=January 9, 2014 |url-status=dead }}</ref> As a result of the excessive lead emissions from the Inco Superstack, soil tests of the surrounding community of Copper Cliff was found to have levels of lead that are sufficient to cause harm to young children.<ref>[http://www.sudburysoilsstudy.com/EN/media/support/reports/SSS_RM_REPORT.pdf Risk Management - Follow Up to the Sudbury Soils Study Human Health Risk Assessment]</ref>

==See also==
* [[List of chimneys]]
* [[List of tallest freestanding structures in the world]]

==References==
{{reflist}}

==External links==
{{Commons category}}
* {{Cite web |url=http://www.emporis.com/buildings/212441/inco-superstack-greater-sudbury-canada |archive-url=https://web.archive.org/web/20150924144633/http://www.emporis.com/buildings/212441/inco-superstack-greater-sudbury-canada |url-status=usurped |archive-date=2015-09-24 |title=Emporis building ID 212441 |work=[[Emporis]]}}
* {{SkyscraperPage|1511}}
* {{usurped|1=[https://web.archive.org/web/20070701043538/http://www.inco-sudbury-airquality.com/ Inco Air Quality Site]}}
* [http://www.northernontariobusiness.com/Industry-News/mining/CVRD-Inco-plugs-sulphur-dioxide-holes.aspx CVRD Inco plugs sulphur dioxide holes]
* [https://www.youtube.com/watch?v=4J8EgTE2eyc 'A View Rarely Seen' - Aerial video footage of the Sudbury (INCO) Superstack]
* [https://www.youtube.com/watch?v=caUPzdiCgJM 'A View Rarely Seen Part II' - Aerial video footage of the Sudbury (INCO) Superstack]

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{{succession box
| title=World's tallest chimney<br/><small>380&nbsp;m (1247&nbsp;ft)</small>
| before=Chimney of [[Mitchell Power Plant]]
| after=[[Ekibastuz GRES-2 Power Station]] chimney
| years=1971–1987}}
{{s-end}}

{{Supertall chimneys}}
{{Authority control}}

[[Category:Towers completed in 1970]]
[[Category:Buildings and structures in Greater Sudbury]]
[[Category:Chimneys in Canada]]
[[Category:Metallurgical facilities]]
[[Category:Industrial buildings in Ontario]]
[[Category:1970 establishments in Ontario]]
[[Category:Vale S.A.]]