Lower Slate Lake Tailings Dam

LOWER SLATE CREEK· City and Borough of Juneau, Alaska· Built 2010· Rockfill· 63 ft tall
Significant Hazard Tailings Private

Key Takeaway

Lower Slate Lake Tailings Dam is classified as significant hazard in Alaska. It was completed in 2010 and is 16 years old. Its primary use is tailings. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 63 ft (taller than 78.8% in AK)
Dam Length480 ft
Dam TypeRockfill
Max Storage2.8K acre-ft
Normal Storage2.3K acre-ft
Surface Area53 acres
Drainage Area1 sq mi
Max Discharge1,020 cfs
Year Completed2010 (16 years old)
NID IDAK00308

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: July 28, 2020
State Regulated: Yes
Regulatory Agency: AKDNR

Ownership

COEUR ALASKA INC.

Private

Frequently Asked Questions

What is the hazard classification of Lower Slate Lake Tailings Dam?

Lower Slate Lake Tailings Dam is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Lower Slate Lake Tailings Dam?

Lower Slate Lake Tailings Dam is owned by COEUR ALASKA INC. (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Lower Slate Lake Tailings Dam built?

Lower Slate Lake Tailings Dam was completed in 2010, making it 16 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Lower Slate Lake Tailings Dam?

Lower Slate Lake Tailings Dam serves the following purposes: Tailings. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Lower Slate Lake Tailings Dam?

Lower Slate Lake Tailings Dam has a dam height of 63 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Lower Slate Lake Tailings Dam last inspected?

Lower Slate Lake Tailings Dam was last inspected on July 28, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.