Coal Combustion Residuals (CCR)

Minnesota Power uses coal as part of a diversified portfolio for energy production to ensure its customers access to reliable and affordable energy. On April 17, 2015 EPA published the Coal Combustion Residual (CCR) Rule. The rule directly impacts coal burning facilities by establishing nationwide criteria for the disposal of coal ash in landfills and surface impoundments. The rule is effective October 19, 2015.

What is CCR?

Coal Combustion Residual (CCR), commonly referred to as coal ash, is the byproduct of coal that remains after it is burned to produce electricity. CCR can also be identified in more specific terms by physical characteristics. Common types of coal ash are fly ash., bottom ash, boiler slag, or flue gas desulfurization (FGD) materials. Coal ash can be handled and stored in wet or dry form. Dry ash is stored in dry ash landfills while ash mixed with water is stored in surface impoundments often referred to as ash ponds.

Existing State Regulatory Framework

All Minnesota Power facilities that generate and receive coal ash are operated safely and are in full compliance with State of Minnesota permits. Permits issued by the Minnesota Pollution Control Agency and the Minnesota Department of Natural Resources are designed to be fully protective of human health and the environment.

Minnesota Power facilities regulated by the federal CCR Rule are Laskin Energy Center and Boswell Energy Center. Taconite Harbor Energy Center discontinued disposal of ash in the facility’s dry ash landfill prior to the applicability date of the CCR Rule, such that Minnesota Power believes that the CCR Rule is not applicable to that landfill.


In 2015, Laskin Energy Center converted its coal burning boilers to natural gas, eliminating the generation of CCR at this facility. The legacy ash pond at Laskin is currently being decommissioned.


Boswell Energy Center continues to generate and safely handle, dispose, and beneficially re-use coal ash. The ash ponds and dry ash landfill are in compliance with all state regulations. Changes will be made to the ash basin as needed to continue to operate in full compliance with all federal CCR Rule requirements.

Taconite Harbor

In 2016, Taconite Harbor Energy Center idled its two units that were still in operation (the third unit having been retired in 2015). Taconite Harbor Energy Center has a state-permitted dry ash landfill. Before the applicability date of the CCR Rule in 2016, Minnesota Power ceased disposal of ash at the Taconite Harbor landfill, such that Minnesota Power does not believe that the landfill is subject to the CCR Rule. Nevertheless, in response to a request by the EPA, Minnesota Power has provided the documents at the above link. By doing so, Minnesota Power does not admit that the Taconite Harbor landfill is a CCR landfill subject to the CCR Rule and Minnesota Power expressly preserves all rights and defenses with respect to such characterization.

Beneficial Re-Use

Recycling of coal ash is referred to as beneficial re-use, a common practice encouraged by the EPA and the Minnesota Pollution Control Agency. Coal ash is used to enhance manufactured products such as grout, concrete, and roofing materials. At Boswell Energy Center, as much of the coal ash as possible is recycled or reused to reduce the need for new materials in manufacturing products as well as reduce the costs associated with coal ash disposal. Ash also is beneficially used to close existing landfills and ash ponds. to learn more about beneficial re-use visit EPA's and/or MPCA's websites:

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