Clinton Creek Asbestos Mine
Executive Summary
Clinton Creek is an abandoned asbestos mine about 100 km northwest of Dawson City, Yukon, within the Traditional Territory of the Tr'ondëk Hwëch'in.[1] Cassiar Asbestos Corporation Ltd. operated it from 1968 to 1978, extracting more than 12 million tonnes of serpentine ore containing 940,000 tonnes of asbestos from three open pits.[1] The ore was serpentinite containing white asbestos, known as chrysotile.[3]
The mine left 60 to 70 million tonnes of waste rock and 12 million tonnes of asbestos tailings in the Clinton Creek and Wolverine Creek valleys.[1] By 1974 the waste rock pile had moved downslope, blocked the valley bottom, and formed Hudgeon Lake.[1] The federal government says asbestos is the primary contaminant of concern, but that the main risks relate to the stability of the tailings and waste rock and the lake impounded behind them.[1]
A 2019 risk assessment for the Government of Yukon predicted unacceptable risks from airborne asbestos for hunter/gatherer and camper groups under site conditions at the time, and found that the tailings are the major source of asbestos on site.[3] The Government of Canada took over sole responsibility for the cleanup in 2025.[1] Work on lowering Hudgeon Lake and upgrading the creek channel was scheduled to begin in summer 2026.[4]
Clinton Creek Mine: At-a-Glance
Clinton Creek Asbestos Mine at a glance:
- About 100 km northwest of Dawson City — on Clinton Creek, 9 km upstream of its confluence with the Fortymile River, which flows into the Yukon River[1]
- 1968–1978 — years Cassiar Asbestos Corporation Ltd. operated the mine, per Crown-Indigenous Relations and Northern Affairs Canada[1]
- 940,000 tonnes of asbestos — extracted from more than 12 million tonnes of serpentine ore in three open pits[1]
- 12 million tonnes of asbestos tailings — deposited along the Wolverine Creek valley, alongside 60 to 70 million tonnes of waste rock along Clinton Creek[1]
- Hudgeon Lake (1974) — formed when the Clinton Creek waste rock pile moved downslope and blocked the valley[1]
- Unacceptable airborne asbestos risk — predicted for hunter/gatherer and camper groups in the 2019 risk assessment update[3]
- Type II site since April 1, 2003 — designated under the Yukon Devolution Transfer Agreement, which left Canada responsible for pre-2003 environmental liabilities[1]
- 2025 — the governments of Canada and Yukon agreed that Canada would assume all responsibility for remediation, funded through the Northern Abandoned Mine Reclamation Program[1]
- 4.25 metres — planned lowering of Hudgeon Lake, with 1.4 km of the Clinton Creek channel to be upgraded[4]
Key Facts
| Measure | Finding (Source) |
|---|---|
| Operator and years | Cassiar Asbestos Corporation Ltd., 1968–1978 — CIRNAC[1] |
| Start date in Yukon's 2003 assessment | October 1967 to August 1978 — Government of Yukon screening-level risk assessment, 2003[2] |
| Ore and asbestos extracted | More than 12 million tonnes of ore; 940,000 tonnes of asbestos — CIRNAC[1] |
| Open pits | Three: Porcupine, Snowshoe and Creek — Government of Yukon, 2003[2] |
| Waste rock | 60–70 million tonnes along the Clinton Creek valley — CIRNAC[1] |
| Asbestos tailings | 12 million tonnes along the Wolverine Creek valley — CIRNAC[1] |
| Airborne asbestos risk (2019) | Unacceptable risk predicted for hunter/gatherers and campers; not predicted for occasional visitors — Wood, for the Government of Yukon, 2019[3] |
| Main source of asbestos on site | The tailings — Wood, 2019[3] |
| Dam classification | "Significant" under Canadian Dam Association guidelines; no permanent population at risk — Wood dam breach assessment, 2019[5] |
| Hudgeon Lake drawdown | 4.25 metres planned — CBC News, March 2026[4] |
| Final closure goal | 2036 — CIRNAC, as reported by CBC News, July 2025[6] |
Where Is Clinton Creek and Who Ran the Mine?
The mine sits along Clinton Creek, called Dätl'äkay dëk in the Hän language, 9 km upstream of its confluence with the Fortymile River.[1] The Fortymile drains into the Yukon River, and that drainage, called Ch'ëdä Dëk in Hän, was an important travel and trade corridor for First Nations people.[1] The site is reached by a seasonal road.[1]
Cassiar Asbestos Corporation Ltd. ran the operation. The federal government dates mining to 1968 through 1978.[1] A 2003 Government of Yukon risk assessment records the mine as operating from October 1967 to August 1978,[2] and a 2019 risk assessment also gives 1967 as the start.[3] The sources do not explain the difference.
Ore came from three open pits, named Porcupine, Snowshoe and Creek, on the south side of Clinton Creek.[2] It was carried by aerial tramway to the mill.[3] The mill buildings and the associated townsite, about 10 km southeast of the mine, were auctioned off in 1978.[2]
What Asbestos Was Mined at Clinton Creek?
The ore was a serpentinite rock containing white asbestos, known as chrysotile.[3] The National Cancer Institute classes chrysotile as serpentine asbestos and notes that it is the form used most widely in commercial applications.[7]
According to the National Cancer Institute, the International Agency for Research on Cancer has found that "there is sufficient evidence that asbestos causes mesothelioma (a relatively rare cancer of the thin membranes that line the chest and abdomen), and cancers of the lung, larynx, and ovary."[7]
For the mineral types and how they differ, see Chrysotile.
What Was Left Behind?
Mining produced two large waste piles. Between 60 and 70 million tonnes of waste rock went into the Clinton Creek valley, and 12 million tonnes of asbestos tailings went into the Wolverine Creek valley.[1]
By 1974, the Clinton Creek waste rock pile had moved downslope, blocked the valley bottom, and formed Hudgeon Lake. Around the same time, the Wolverine Creek tailings pile blocked the Wolverine Creek valley.[1]
In 1992, before bankruptcy and abandonment, Cassiar Asbestos Corporation Ltd. decommissioned most of the site infrastructure, including the mill, tram and camp.[1] The site was abandoned after the company's bankruptcy.[1]
What Are the Health Risks at the Site Today?
The 2019 Human Health and Ecological Risk Assessment Update, prepared by Wood for the Government of Yukon, looked at soil, country foods and airborne asbestos fibres.[3] Its human health conclusions included:[3]
- Unacceptable risks due to airborne asbestos exposure are predicted for the hunter/gatherer and camper receptor groups under the site conditions assessed.
- Unacceptable risks due to airborne asbestos exposure are not predicted for occasional site visitors.
- Where tailings remain accessible and could be disturbed, there are potential unacceptable risks to human health from inhaling airborne asbestos and/or direct exposure to nickel in the tailings.
- Where there is no access to and no disturbance of the tailings, unacceptable risks are not predicted.
- The tailings contain consistently higher metals and asbestos content than the waste rock and soil, and are the major source of asbestos on site.
The assessment states that its findings describe the conditions at the time and would need to be revised if site conditions change during closure and reclamation.[3]
The federal government frames the site's main risks as physical. Asbestos is the primary contaminant of concern, but the main risks relate to the stability of the tailings and waste rock and the impoundment of Hudgeon Lake behind them.[1] A 2019 dam breach assessment classified the waste rock dam as "Significant" under Canadian Dam Association guidelines, noting that no permanent population is at risk.[5] It modelled a breach as raising water levels on the Fortymile and Yukon rivers by about 1.4 m, "which is still well within bank levels of each river."[5]
Who Is Responsible for the Cleanup?
On April 1, 2003, the abandoned mine was designated a Type II site under the Yukon Northern Affairs Program Devolution Transfer Agreement.[1] Under that agreement, the Government of Canada is responsible for pre-2003 environmental liabilities and remediation costs at abandoned Type II mine sites, which at Clinton Creek covers all liabilities on site.[1] Canada funded and planned the work, the Government of Yukon handled care, maintenance and monitoring, and both worked with the Tr'ondëk Hwëch'in, the Affected First Nation.[1]
In 2025, the governments of Canada and Yukon reached a new agreement under which Canada assumed all responsibility for remediation, in addition to funding it through the Northern Abandoned Mine Reclamation Program.[1] Work is done in consultation with the Tr'ondëk Hwëch'in.[1]
The remediation objectives the three governments set in 2015 are to protect human health and safety; protect the environment, including land, air, water, fish and wildlife; return the site to a state that supports community and traditional land uses; maximize local, First Nation and Yukon socio-economic benefits; and minimize project liability, risk and costs.[1]
What Has Been Done So Far?
The federal timeline for the site records the following milestones:[1]
- 2002–2003 — construction in the Clinton Creek channel to stabilize the lake outlet and reduce the risk of downstream flooding
- 2006 — Government of Yukon care and maintenance begins
- 2010 — a significant flood damages part of the Clinton Creek channel, later repaired with an articulated concrete block mat chute (2015–2016)
- 2018 — interim repairs after erosion damage, including large riprap and reshaped embankments
- 2019–2020 — closure concepts developed and costed at 10 percent design; selection paused until approaches consistent with current risks and available funding could be developed
- 2023 — cost-sensitivity analysis for long-term channel upgrades; two feasible options identified
- 2025 — preferred channel upgrade option selected; Canada assumes management of the site from Yukon
What Is Happening in 2026?
In March 2026, CBC News reported that the planned work includes mining and hauling material from the Kilometer 63 quarry, upgrading 1.4 kilometres of the Clinton Creek channel, and lowering Hudgeon Lake's water level by 4.25 metres.[4] Channel upgrade work was tentatively scheduled to begin in summer 2026.[4]
In September 2026, Canadian Occupational Safety reported that remediation was beginning, with the current phase focused on lowering Hudgeon Lake to reduce flood risk and building fish passage through the Clinton Creek channel.[8]
CIRNAC told CBC News in 2025 that it could not give a timeline for a final reclamation plan, and that the goal is final closure of the site by 2036.[6]
Frequently Asked Questions
Where is the Clinton Creek asbestos mine?
About 100 km northwest of Dawson City, Yukon, on Clinton Creek, 9 km upstream of the Fortymile River, within the Traditional Territory of the Tr'ondëk Hwëch'in.[1]
When did Clinton Creek operate?
The federal government dates operation to 1968 through 1978.[1] A 2003 Government of Yukon assessment records October 1967 to August 1978.[2]
What kind of asbestos came from Clinton Creek?
Chrysotile, or white asbestos, mined from serpentinite rock.[3]
Is it safe to visit the Clinton Creek mine site?
The 2019 risk assessment did not predict unacceptable airborne asbestos risk for occasional visitors, but did predict it for people hunting, gathering or camping on site, and flagged potential risks wherever the tailings are accessible and disturbed.[3] Those findings describe conditions in 2019, and remediation is now changing the site.[3][8]
Who is paying for the cleanup?
The Government of Canada, which assumed all responsibility for remediation in 2025 and funds it through the Northern Abandoned Mine Reclamation Program.[1]
What is Hudgeon Lake?
A lake formed by 1974, when the Clinton Creek waste rock pile moved downslope and blocked the valley.[1] The cleanup plans to lower it by 4.25 metres.[4]
Can asbestos from a mine like Clinton Creek cause mesothelioma?
The International Agency for Research on Cancer has found sufficient evidence that asbestos causes mesothelioma, as reported by the National Cancer Institute.[7] The NCI also notes that symptoms of asbestos-related diseases "may not become apparent for many decades after the exposure."[7]
Quick Statistics
- 940,000 tonnes of asbestos extracted[1]
- 12 million+ tonnes of serpentine ore mined from 3 open pits[1]
- 60–70 million tonnes of waste rock[1]
- 12 million tonnes of asbestos tailings[1]
- 1974 — Hudgeon Lake forms behind the waste rock[1]
- 1992 — most site infrastructure decommissioned[1]
- 2003 — designated a Type II site[1]
- 2025 — Canada assumes all responsibility for remediation[1]
- 4.25 m — planned Hudgeon Lake drawdown[4]
- 2036 — goal for final closure[6]
Related Pages
- Asbestos Miners
- Chrysotile
- Vermiculite and Libby Montana
- Environmental Asbestos Exposure
- Pleural Mesothelioma
- Mesothelioma Prognosis
External Links
- Government of Yukon — Clinton Creek mine site reports — historical and current engineering, water-quality and risk-assessment reports on the abandoned mine
- Danziger & De Llano — Malignant Mesothelioma — overview of malignant mesothelioma and its link to asbestos exposure
- Mesothelioma.net — patient resources, treatment information, and compensation guides
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 1.29 1.30 1.31 1.32 1.33 1.34 1.35 1.36 1.37 1.38 1.39 1.40 1.41 1.42 1.43 1.44 1.45 1.46 1.47 1.48 1.49 1.50 1.51 Clinton Creek Mine Remediation Project, Crown-Indigenous Relations and Northern Affairs Canada, page modified 2026-03-11.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Final Report on Human Health Screening Level Risk Assessment for Clinton Creek Abandoned Asbestos Mine, Government of Yukon, 2003.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 3.14 Clinton Creek Remediation Project: Human Health and Ecological Risk Assessment Update, Wood Environment & Infrastructure Solutions for the Government of Yukon, July 2019.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Tentative remediation plan outlined for Yukon's Clinton Creek mine, Isabella Calissi, CBC News, March 20, 2026.
- ↑ 5.0 5.1 5.2 Clinton Creek Remediation Project: Dam Breach Assessment, Wood Environment & Infrastructure Solutions for the Government of Yukon, 2019.
- ↑ 6.0 6.1 6.2 Federal government assumes control of Clinton Creek remediation in the Yukon, CBC News, July 30, 2025.
- ↑ 7.0 7.1 7.2 7.3 Asbestos Exposure and Cancer Risk, National Cancer Institute.
- ↑ 8.0 8.1 Crews to reshape asbestos tailings as Clinton Creek mine cleanup begins, Jim Wilson, Canadian Occupational Safety, September 22, 2026.