Red Brush Road Project
Alcoa’s property west of Yankeetown Road, north of Red Brush Road and south of Eble Road, was mined prior to reclamation laws enacted in 1977. The mining left an old "strip pit" that is commonly referred to as the "Y Pit" (due to its shape). For several years, the Indiana Department of Natural Resources (DNR) Division of Abandoned Mine Lands (AML) has discussed with Alcoa the potential reclamation of the site by filling in the pit to mitigate safety issues associated with the high wall on the pit’s east side. The reclamation will use Coal Combustion Products (CCPs) for fill material and will take the contour of the land closer to its original configuration.
Characterization of Structural Fill Material
Alcoa has managed the fly and bottom ash produced at the Warrick Power Plant (WPP) for more than 50 years, establishing a solid knowledge base about CCPs and how they react in the environment. Ash is the oxidized mineral content that remains when coal is burned to make electricity. Alcoa did not add the minerals to the coal. Rather, they were present when the coal was mined, either from the natural environment in which the coal was formed or by the mining process itself, which may have penetrated surrounding rock layers.
In 2005, Alcoa Warrick began to develop a new strategy for CCPs because existing handling solutions would become insufficient by 2010. Alcoa actively pursued numerous options, including the sale of the material to various industries, including cement and aggregate businesses.
The nearly $500 Million investment to install scrubbers at WPP to reduce air emissions by more than 60% is also creating a new need to manage a byproduct of the scrubbers: Wallboard-grade gypsum. This is the same material used to make the drywall found in most homes. Alcoa has a contract to sell the gypsum for the first five years of the scrubber’s production, but a plan is needed if Alcoa is unable to sell the remainder.
None of the CCPs to be used at the Y pit – fly ash, bottom ash and gypsum – are considered hazardous wastes by the Environmental Protection Agency. In fact, several states and countries have embraced their use as a reclamation/structural fill material.
In December 2006, Alcoa began further characterization of the CCPs, including tests for dissolved metals of the CCPs and also testing the water where CCPs have been stored. Tests were conducted on fly ash, bottom ash, gypsum, and water drawn directly from Alcoa's "C" Pond, where ash has been managed since 1978.
Characterization of the Red Brush Road Site
In late 2006 and continuing into 2007, Alcoa has been doing work to ensure a thorough understanding of the Red Brush Road site and its surrounding environment. This work has included a phased site exploration; ground water and surface water chemical characterization; geotechnical and hydro geologic analyses; and testing of water samples from various wells and the Y Pit itself.
Specifically, Alcoa worked with an experienced contractor to install eleven wells around the Y Pit in 2006, and an additional five wells in 2007 as step-offs from these wells. In 2008, after meeting with the project neighbors, three more wells were added. In addition to the contractor, a veteran professor of geology from the University of Southern Indiana has consulted with Alcoa to increase the understanding of the site’s geology and development of site characterization plans. The Indiana State Geological Survey, through an Indiana University professor, is also consulting on the project.
With more than 12 months of sample collections, Alcoa has gathered data on water quality and groundwater levels during record wet weather and during drought conditions. Each distinct condition has demonstrated different attributes about the site, creating a comprehensive database that will guide reclamation work.
The groundwater in the area is not being used for drinking water (humans or domestic animals), and does not meet current drinking water standards. It may be discolored and might stain clothing or porcelain plumbing fixtures due to elevated iron, manganese and aluminum and would likely have an unpleasant taste due to elevated levels of iron, manganese, and total dissolved solids. Water samples taken from Alcoa's "C Pond" (where ash is currently managed) have been tested and compared with drinking water standards. The tests showed that the water from the C Pond, which has been in contact with the CCPs, is of comparable quality, based on drinking water standards, to the water in and near the Y pit. The groundwater flow in the highwall (unmined) side is significantly lower and is not capable of producing sufficient water quantity and quality for a modern, domestic household.
Samples of the CCPs were compared to soil samples from a Newburgh-area public park and tested for 25 different constituents. In only two cases (sulfates and dissolved solids) were the concentrations significantly greater in the CCPs than in the park’s soil.
Ensuring Future Protection of the Environment and Neighbors
Any work ultimately done on the site would be covered by specific construction and inspection standards. The work will also be covered by a National Pollution Discharge Elimination System (NPDES) permit, which establishes what parameters will be monitored on an ongoing basis during the project’s construction and reclamation phases.
Compaction rates will be controlled to ensure that the site remains structurally sound. Alcoa will also control dust at the site by maintaining the moisture level in the CCPs. The moisture and other control methods should limit airborne material.
The placement of ash is not anticipated to adversely affect any usable groundwater. As part of the reclamation, however, Alcoa will install a compacted soil buffer on the highwall side of the pit for increased groundwater protection. Also, ditches and other methods will be used to divert surface water flow away from the site.
The CCPs used for fill do not have inherent odors, and Alcoa does not currently experience odor problems where the materials are currently managed.
Work will be conducted Monday through Friday between 7 a.m. and 5 p.m., with some weekend shifts. Equipment used at the site will be conventional dump trucks, rubber-tired bulldozers, water trucks and road graders. Any traffic associated with the site and the hauling of materials will be contained on Alcoa property. The only use of public roads will occur at the crossing with Red Brush Road.
Finally, the dense tree growth on Alcoa property will serve as a natural barrier between the Y Pit and most neighbors. Alcoa has been working to minimize any potential inconvenience for homeowners who live near the site. This carefully-considered reclamation project is expected to improve safety by eliminating a dangerous artifact of prior mining operations.