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Proposed Regulatory Framework for

Beneficial Use of Coal Combustion Products

as Geotechnical Construction Material

(Draft 5/22/09)

Background

Coal Combustion Products (CCPs) can be safely and effectively used as geotechnical construction

material in properly engineered and constructed beneficial reuse projects. Some, but not all CCPs can be

equivalent and sometimes superior materials for use as geotechnical fill compared to natural mined

alternatives. However to mitigate any possible risks to the environment or to human health, CCPs need

to be properly characterized and evaluated and projects need to be properly engineered and managed.

While hundreds of such projects have been implemented successfully without detrimental impact on

the environment, a few poorly planned and executed projects, utilizing the wrong materials in the

wrong applications have raised concerns. Moreover, some entities have inappropriately described some

large scale disposal programs as beneficial reuse applications, further clouding the picture and calling

into question the future legitimate beneficial reuse of these materials.  

The EPA has indicated its intention to develop proposed rule making by the end of 2009 to address the

management and disposal of coal combustion residuals in disposal facilities. As the current regulations

concerning management of CCPs are being reconsidered, the opportunity exists to implement a

regulatory framework for safe and effective management of CCPs for use as geotechnical construction

materials so as to preserve and enhance the long term environmental and economic benefits that result

from this activity.  Implementation of appropriate regulatory oversight and applicable engineering and

environmental guidance can ensure that risks to the environment are minimized and inappropriate uses

and projects are curtailed. A regulatory and engineering framework that works across State jurisdictions

can encourage safe beneficial reuse activities in new areas, expanding the positive impacts on the

environment and the economy.  

Why Use CCPs as Geotechnical Construction Material?

Properly designed and implemented geotechnical fill projects can offer an environmentally friendly and

economically positive way to beneficially reuse CCPs which can contribute to the long term sustainability

and economic vitality of the community in a number of ways:

1. Beneficial reuse of CCPs conserves natural resources. By reusing CCPs in place of virgin materials

as geotechnical construction material, the need for new mining or creation of new borrow pits is

reduced. This prolongs the availability of local materials to projects and reduces the

environmental damage caused by mining and related transport and extraction activities.

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2. Beneficial reuse of CCPs reduces CO2 emissions. As the result of energy savings achieved from

reduced mining activity and the typically reduced distances required to transport reuse material

from source to jobsite, less CO2 is released into the atmosphere.

3. Beneficial reuse of CCPs strengthens local economies. Local economies are benefited as the

result of the availability of lower cost construction materials that frequently make an otherwise

unaffordable project feasible. This is particularly valuable for public facilities and projects

including road construction, agricultural infrastructure and expanding small businesses. In some

cases, these projects result in previously unusable land being converted to productive, taxable

use. In these areas and others, beneficial reuse of CCPs as geotechnical construction material

promotes economic activity that creates jobs.

4. Beneficial reuse of CCPs preserves landfill space. CCP material utilized as geotechnical

construction material is kept out of landfills and impoundments thereby preserving the space

for other disposal needs and prolonging the useful life of existing landfills. CCPs are the second

largest industrial byproduct stream in America today, expected to grow to as much as 170

million tons annually by 2015. Absent alternative use, the disposal of this enormous volume of

materials would require the development of hundreds of new landfills.  

5. Beneficial reuse saves money   Utilizing CCP materials in a construction project in place of virgin

fill materials can save hundreds of thousands of dollars in the cost of a project. Utilities may find

that having their CCPs used in beneficial use projects is less costly than disposal, which can

translate into lower rates for utility customers.   

Achieving these substantial benefits cannot be done at the expense of the environment. Potentially

damaging constituents within the materials must be understood and safeguards must be established so

that any risks to the environment or to human health are eliminated.  

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The remainder of this document suggests technical and environmental guidelines that could be

incorporated in a regulatory framework that should be adopted for the use of CCPs as geotechnical

construction material. These guidelines parallel some of the most comprehensive and progressive

regulations now being utilized at the State level, and add new considerations to further insure the safety

and viability of all such projects in the future.  

Utilization of CCPs as geotechnical construction material must take in to account that a sizable body of

scientific study of CCPs clearly identifies certain risks in using the material that must be well understood

and guarded against in reuse applications. Universal, standardized and accepted materials testing

protocols should be followed to establish both the chemical makeup and geotechnical properties of

CCPs for reuse. Materials identified through testing to pose potential risk to the environment should be

restricted from use. CCPs should only be used as geotechnical construction material in projects where

the materials are unlikely to be disturbed over time and the potential for direct contact with human

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activity is remote. Projects should be designed so as to physically isolate the materials from current or

future contact with ground water or the potential to leach damaging elements into aquifers. Materials

should be placed and compacted in such a manner that permeability is limited and segregation from the

surrounding environment is assured. Finally, once projects are completed, suitable design and

environmental documentation and notification should be maintained to reduce the possibility that the

materials will be disturbed or disrupted in the future or the original design compromised.  

To achieve these objectives, a regulatory frame work is proposed in the attached Appendix A that

establishes five steps in the process of utilizing CCPs as geotechnical construction material:  

Step 1: Evaluate the Materials

The inorganic and organic components of the CCPs proposed for reuse should be evaluated with respect

to an identifiable set of standards to protect human health and the environment so as to provide

specific risk based design standards for use. CCPs that do not meet these standards should not be used

as geotechnical construction materials. Materials should also be tested using standard geotechnical

engineering tests to determine what uses are appropriate for the material.  

Step 2: Qualify the Beneficial Use

Use of the materials should be confined to projects that constitute legitimate beneficial use identified in

a specific listing of suitable projects. Applications of the material should be based on good engineering

practices guided by nationally recognized standards.

Step 3: Evaluate the Proposed Project Site

The physical characteristics of the project site including soil, surface and groundwater resources, land

use, natural resource values and adjacencies must be assessed and factored into the design.  

Step 4: Standardize the Design and Construction Process

Good engineering practices should be used to design and construct projects including standard

environmental safeguards to minimize the impact to land, air and water, during and after construction.  

Step 5: Follow Up after the Project is Complete

Risk based factors should be used to determine the need, extent, and length of time that projects should

be monitored to evaluate their physical integrity following project completion. Each project should be

documented and recorded and provisions should be made to inform future land users of the presence of

the CCP materials.

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Appendix A

Proposed Regulatory Framework

The following proposed regulatory framework is based on a review of regulations of CCPs in various

states, extensive implementation experience, engineering judgment, and practical issues related to the

public’s acceptance of the use of the material.  This proposed regulatory framework would be applicable

to all use of CCPs as geotechnical construction material and could be further supplemented by state and

local guidelines where appropriate.  

1. MATERIAL ASSESSMENT

a. CCPs would be tested in order to determine their potential to impact the environment

and human health.  A set of categorical standards would be used to guide the

appropriate use and engineering design compatible with its potential to impact the

environment.  Standard tests such as those included in EPA SW‐846 should be used.

Based upon this testing, specific uses would be defined for the acceptable use of the

material as geotechnical construction material.  

b. CCPs would also be tested to determine compaction properties as measured by Proctor

tests and load bearing capacity (e.g. CBR).  ASTM E‐2277‐03 Standard Guide for Use of

Coal combustion byproducts in Structural Fills can be utilized for this purpose.  

2. DETERMINATION OF BENEFICIAL USE

Those applications that would be considered acceptable beneficial use of CCPs as geotechnical

construction material will be limited to the following:

a. Subgrade fill for the construction of commercial, industrial and agricultural buildings (but

not residential buildings).

b. Subgrade fill for the construction of a paved parking or storage surface

c. Subgrade fill for the construction of a paved roads including federal, state, and municipal

roadways

d. Utility trench back fills

e. Bridge abutment backfills not associated with road riparian crossings

f. Transportation facility embankments  

g. Reclamation of inactive quarry high walls for safety purposes  

h. Sight and sound and safety berms for screening, sound attenuation and physical protection

i. Development of land for future commercial and  industrial use

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3. PROJECT SITE

Suitable sites for beneficial use of CCPs as geotechnical construction materials must meet the

following characteristics:

a. Removed from any wetlands or surface waters

b. Minimum setback from closest water well.

c. Separated from nearest residential use by a minimum distance.

d. Appropriate site zoning not including residential use

e. No potential impact on threatened or endangered species  

4. DESIGN AND CONSTRUCTION

The following minimum set of standards is to be applied to project design and construction:

a. CCP materials should be placed so that they are separated from seasonal high

groundwater levels by a minimum distance that reflects the nature of the soils and the

hydrology of the area.

b. Erosion control measures should be established as well as procedures to minimize

dusting including the covering of trucks delivering materials to the site.

c. Materials should be placed in layers of uniform thickness and properly compacted to

achieve required density through the full depth of the layer.

d. Materials determined by testing to be suitable for use in an unconfined geotechnical fill

application should be covered with a minimum depth of native soils and seeded as soon

as practical after placement.  

e. Materials determined by testing to be suitable for use in a confined geotechnical fill

application should be covered with an impervious surface such as concrete or asphalt

and side slopes should be covered with native soils, configured to allow for proper

water runoff and seeded as soon as practical after placement.  

5. FOLLOW UP

Following project completion, performance of the project relative to design specifications is to

be monitored as follows:

a. Post project Inspections of cover material of the site or monitoring of water infiltration

by use of a lysimeter or other device should be considered for very large fill projects,

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factoring in the nature of the use, the soils involved, the potential for environmental

risk, and the design of the project.  

b. At the completion of larger projects, information regarding the fill should be recorded

on the landowner’s deed for the property.   

For all projects utilizing CCPs as geotechnical construction material, documentation would be

maintained for a minimum of five years following project completion, including a summary of

the size, depth and volume of the fill, and the material used and the environmental

characteristics of that material.  

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