Since the facility was initially proposed in 2003, Triad has been supporting the development of Longview Power Plant, located near Fort Martin, Monongalia County, WV. Longview Power, owned by GenPower Holdings, L.P., will be a 695 megawatt supercritical pulverized coal-fired generating facility geared to provide “clean, reliable and sustainable power generation” to the regional area, which currently faces growing electricity demands and limited capacities for new power. Currently, a contract is in place with PPL Corp. to purchase 300 megawatts of electricity once the plant is operational. The remaining output will be sold through the PJM east coast wholesale electricity market.
Construction on the plant began in January 2007, and the total cost of the development is estimated to be near $1.82 billion. Work is being led by a joint contractor consortium of Siemens Power Generation, Inc. and Aker Construction, Inc. Triad has provided services for both firms, as well as other subcontractors, in the areas of geotechnical investigations, drilling and sampling, surveying and mapping, and materials testing.
Numerous subsurface investigations have been conducted since the preliminary exploration was completed in 2004. Explorations have included drilling for plant structures, coal handling facilities, dam embankments, water lines, pump stations, storage tanks, water treatment facilities and river intake structures. Drilling to investigate the river intake structure area was conducted from a barge in the Monongahela River.
Up to 100 feet of surface mine spoil was penetrated beneath some areas of the site. Deep foundations, consisting of micropiles, were deemed the most cost-effective support for the larger plant structures. Potential settlements were computed for smaller buildings that were to be founded on spread footings or mats, and recommendations were provided to minimize the potential detrimental effects of the pyritic materials contained within the mine spoil. Abandoned deep mines, some of which were not mapped, are also present beneath portions of the site. Triad conducted an evaluation of the potential for subsidence, aided by deep core borings, beneath the planned freshwater dam embankment and reservoir area. Based on the findings of this evaluation, the dam was eliminated in favor of an above-ground water storage (tank) system.
Triad’s surveying crews have provided ongoing support with establishment of horizontal and vertical control benchmarks, mapping of the site throughout development, construction and boring stake-outs, as-built position surveys, and survey design. Field services and testing personnel are also on-site regularly, and will continue to monitor portions of the construction until the plant is completed.