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Some contractors might be intimidated by large-scale projects, but C.J. Mahan Construction Co. has made these its main focus. Based in Grove City, Ohio, the firm specializes in heavy civil engineering projects, including the development and rehabilitation of bridges, water treatment facilities, locks and dams.

Founder Charles Jeffrey Mahan started the company in 1972 as a surveying business. Over time, the company expanded to provide construction and construction management services, and today, it is known for such projects as bridges spanning the Ohio River and civil structures in Ohio, West Virginia, Kentucky, Indiana and Tennessee.

C.J. Mahan “is dedicated to safety, the creation of cost-effective projects and the innovative application of progressive, dynamic construction techniques and equipment,” it says. “Integral to its successful strategy is the recruitment and development of quality core personnel, responsible growth and financial conservatism.”

Powering Up

C.J. Mahan’s current projects include American Municipal Power (AMP) Inc.’s Smithland Hydroelectric plant project on the Ohio River and near Smithland, Ky. C.J. Mahan will design and construct a cofferdam for the project, which is one of several AMP has developed at the existing dams on the Ohio River.

“AMP is embarking on an aggressive generation asset development effort designed to diversify the power supply portfolio of our member companies and provide insulation from the volatile wholesale electric market,” AMP President and CEO Marc Gerken said in a statement. “Hydroelectric generation is an important component of AMP’s power supply strategy.”

According to AMP, a run-of-the-river facility like this one will use the river’s natural flow and elevation drop from the high to the low side of the dam to generate electricity. C.J. Mahan’s cofferdam will divert water during construction.

“The Smithland Hydroelectric project has an estimated capacity of 76 megawatts and represents a capital investment of approximately $432 million,” AMP says. “Once the plant is operational, it will employ seven [to] nine permanent operators.”

Deep Analysis

C.J. Mahan’s team on the Smithland project includes Paul C. Rizzo (RIZZO) Associates Inc., a Pittsburgh-based engineering firm that specializes in work in the dam, nuclear power plant and tunneling markets. According to RIZZO, it was hired to design the excavation and associated dewatering system.

To design the dewatering system, RIZZO says it conducted pumping tests to characterize the hydrogeologic properties of the site’s subsurface materials. “The data obtained during the five pumping tests were analyzed by RIZZO to determine the hydraulic conductivities of the upper sand, lower sand, and gravel and bedrock,” it says.

In addition, the company also performed two-dimensional seepage analyses with the Sepp2D program and three-dimensional analyses with the Visual MODFLOW software package. With the results, RIZZO could complete its design for the system, “which includes the installation of 65 36-inch-diameter deep wells,” the company adds.

Reliable Services

Based in Columbus, Ohio, AMP is a nonprofit organization that owns and operates electrical facilities. The corporation was founded in 1971 when a group of municipally owned electric systems partnered to lower costs and increase the reliability of the power supply to the benefit of consumers and owners.

Now, AMP serves public power communities in Ohio, Pennsylvania, Michigan, Virginia, Kentucky and West Virginia, along with a joint action agency in Delaware. “As a nonprofit corporation, we are owned and governed by our members, who are in turn owned and governed by their more than 565,000 customers,” it states.

“AMP manages and supplies competitively priced, reliable wholesale power to member municipal electric systems,” the company continues. “We purchase wholesale electric power and sell it to members at rates based on the purchase price and dispatch fees, plus a small service fee.”

AMP also operates an energy control center to serve its member communities. “AMP owns and manages a diverse array of power resources, allowing members to select the sources that best meet their unique needs,” it states. “We [also] own fossil fuel and renewable generation [resources] and are developing a number of other generation assets to meet members’ short- and long-term needs through a variety of joint ventures.”


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