ASH POND SERVICES

The underground is the most complex environment in construction, and coal ash ponds are no exception. Required compliance with the recent CCR Rule has created an additional challenge to pond closure – a deadline. Time is running out.

No company has more experience with the complexities of underground construction than Moretrench and no company is better suited to help close these ponds in the allotted timeframe.

Closure Options
Overview

To comply with EPA-mandated regulations for the closure of coal ash impoundments, ash drainage is required for either clean closure or cap in place to safely execute closure plans. Water treatment, perimeter cutoff barriers, and dam/levee rehabilitation will also be necessary for the compliant closure of most ponds.

No other contractor has greater experience in stabilizing ash and industrial by-product than Moretrench. Our engineering and operations teams work closely with Owners, Engineers and General Contractors to develop and implement plant-specific closure plans.

Clean Closure

Stabilizing ash ponds using predrainage dewatering for safe and efficient ash removal presents very specific challenges. The interaction of the ash pond with the surrounding aquifer, ponds or cooling water channels and the potential impact of any “hidden” external sources of water recharge, such as old stream beds or springs, must be thoroughly investigated and understood. A small amount of inflow into the base of the pond can render a tremendous amount of ash unstable. To ensure safe excavation and removal of the ash thorough drainage is essential. Adequate site characterization, most effectively accomplished with pilot dewatering tests is necessary for an effective plan. With a finite amount of compliance time remaining, early action is both prudent and cost effective.

Cap In Place

Where water levels are close to the pond surface, predrainage dewatering of the ash is essential to create a surface crust that will safely support construction equipment in order to perform cuts and fills and place a cap. Due to the variability of the ash, the thickness of the crust that will be required will vary from pond to pond, and should be evaluated with a pilot dewatering test prior to the start of construction. Permanent subsurface cut-off barriers can be installed to prevent the off-site movement of water. Embankment stability, utility support, and protection of outfall pipes can be achieved through a number of ground improvement techniques such as jet grouting and ground freezing.

Real Results

A wellpoint pilot test was performed to evaluate the drainage characteristics of the ash. Prior to, and after 10 days of system operation test pits were dug to evaluate the before and after effects of pre-drainage dewatering. This video shows the dry stable excavation through what was previously highly unstable wet ash.

Experience First

We have been applying our specialty services to ash and industrial by-products such as gypsum since the early 1980s. Given our experience of several clean closures, numerous pilot tests, and more than 3,000,000 cubic yards of product dewatered to date, a call to Moretrench will be the only call you need to make.

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NO ONE HAS SEEN MORE

At Moretrench we’ve been resolving challenging geotechnical problems for the civil, industrial and environmental industries for over 100 years. In fact, Moretrench pioneered the first practical dewatering wellpoint, revolutionizing the approach to deep excavation and paving the way more efficient and safer construction practices.

The wellpoint and the deep well are core services that have been applied countless times, nationally and internationally, to dewater and thus stabilize saturated soils and industrial by-product for efficient handling. We also offer a wide range of geotechnical methods to complement our dewatering services. These include grouting techniques and cut-off and containment methods for applications such as dam seepage control, groundwater cut-off and containment, support of existing utilities, and protection of outfall pipes.

We have earned our reputation as an industry leader through product quality, commitment, and a corporate philosophy that emphasizes safety as much as service. Whatever or wherever the challenge may be, we have the technology, the expertise and the people to deliver the optimum solution.

Talk to a Moretrench Coal Ash expert today.

PILOT DEWATERING TESTING

Every ash pond has its own personality.

Every pond is different. There are variations in the type of coal burned, boiler performance, method of ash transportation, deposition at the pond, subsurface soils, and size, shape pond and settlement profile of the pond. Conditions can also vary widely within each individual pond. Grain-size will vary from coarse to fine between the deposition point and the outfall. Accurate determination of the hydrogeological behavior of the pond by pilot testing is therefore critical to an early and effective resolution.

The Moretrench pilot dewatering program goes hand in hand with the geotechnical site investigation. It will reveal vital information on the properties and behavior of the ash and if relevant, the underlying soil. This will assist the design of the dewatering program – whether deep wells or wellpoints are required, and the number, depth of installation and arrangement of the dewatering devices. To define the personality of your pond, and start to determine a plan of action, talk to our ash pond experts today.

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SERVICE PROGRAM

The collective experience of the Moretrench team is uniquely qualified to help manage the complexity of these pond closures. The core services we’re able to apply to these projects are:

A PERSONALITY FOR EVERY POND -TRIED AND TRUE CONSTRUCTION SOILS PRACTICES HOLD PROMISE FOR ASH POND DEWATERING. ASH AT WORK ISSUE 2, 2015

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Source: Ash At Work, Issue 2 2015 As the clock ticks down toward mandatory compliance with the Environmental Protection Agency (EPA) coal combustion residuals (CCR) ruling, facility owners and their…

UNDERGROUND CONSTRUCTION EXPERT PROVIDES NEEDED CLARITY ON MANDATED ASH POND CLOSURES. POWER MAGAZINE, 7/28/2015

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The underground is the most complex environment in construction, and coal ash ponds are no exception. By now, everyone is aware of the recent CCR ruling, which provided technical requirements…

Construction Considerations Are Key in Closure Planning for Coal Ash Ponds

| Coal Ash | No Comments

Mark Johnson, PG and Kent Nilsson, PE When faced with a variety of options for coal ash pond closure, use a holistic approach rather than choosing what seems to be…

Ash Pond Brochures & Technical Papers

TALK TO US

Whether you’re ready to have us visit your project site, or you just would like a questions answered by our team of experts, we’re here to talk to you.

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