Coal Age

SEP 2013

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coal handling continued During train unloading operations, the train moves continuously over the hopper at 0.232 miles per hour and coal is sent to stockpile at a rate of 2,800 tons per hour (tph). serves the ski resort and community of Steamboat Springs; • Electrical transmission lines, plant ponds and ash disposal pit; and • Wildlife habitat (bald eagle, migratory birds, game animals) and significant agricultural properties. To determine the best new coal delivery method, working with local government officials, the community and various agencies, more than 26 options of delivery routes were studied. Options included rail delivery, truck delivery, and combinations of rail/conveyor delivery and rail/truck delivery. The estimated costs for these options ranged between $15 million and $85 million. In the spring of 2007, after an exhaustive analysis in a public process, Xcel Energy applied to the county for a special use permit (SUP) to obtain the necessary approvals for a rail link from the Hayden power plant to the nearby railroad mainline track. A preferred option was selected from among the 10 alternatives that received detailed analysis. The county approved the permit for the rail link in the fall of 2007. In addition to the major county SUP, at least 22 other permits or approvals were required from various state, county and other interested agencies. Detailed Engineering Led by CDG Engineers of St. Louis, Mo., detailed engineering began in January 2008. The project was designed in accordance with the county SUP and conditions, mitigation agreements, railroad standards and requirements, and CDOT standards, requirements and agreements. 26 www.coalage.com The chosen rail spur route used Xcel Energy's existing 75-ft wide right-of-way from the existing mainline rail into Hayden Station. Approximately 2,700 ft of the spur passed through designated wetlands of the Yampa River. Careful attention was required to keep the amount of wetland disturbance below 0.5 acre to qualify for a Corps Nationwide Permit 14 for Linear Transportation Projects. The narrow right-of-way precluded the use of conventional earthen side slopes and a portion of the track was elevated on a system of 22-ft wide parallel retaining walls. These retaining walls were built from 2,200 individual stacked precast concrete units, weighing up to 6 tons each, and having an architectural surface finish with an appearance of natural stacked stones. The rail spur was 1.75 miles long, rising 100 ft in elevation between mainline and the plant, with a maximum grade of 1.6%, and required four new rail bridges— two over public roads, one stream crossing and one wildlife opening. The design required the relocation of major utilities to meet code requirements for track clearances. A high-pressure gas pipeline, 169kV electrical transmission line, 138kV distribution line, and plant raw water pipelines were relocated. A short length of the county road was also relocated. Geotechnical testing was conducted along the rail spur route to ensure that all potential geologic hazards were identified and mitigated. An area of slope instability was discovered and a lateral force resisting system was designed to address the stability issues. At Hayden Station, the existing coal unloading and coal handling systems were evaluated and considered for modification to allow for the new use of train unloading. It was determined that the existing coal stockpile systems could not be economically modified to safely accommodate the higher demands required for train unloading. A new coal unloading facility—including enclosed hopper, stockpile conveyor and a stacking tube—was designed to accommodate either train or truck fuel delivery. The facility was designed to accommodate a unit train composed of four locomotives and 115 rapid discharge bottom dump coal cars. During train unloading operations, the train moves continuously over the hopper at 0.232 miles per hour and coal is sent to stockpile at a rate of 2,800 tons per hour (tph). Rail car doors are opened and closed automatically. Under design conditions, a 115-car unit train can be unloaded in about 5 hours. A 60-inch wide, 2,800-tph stockpile conveyor was designed to carry coal from below the dump hopper to the top of a new stacking tube. This new, totally enclosed conveyor was designed at a slope of 14.5°, 3° flatter than previous sloped conveyors on the site. Using a reduced conveyor slope allowed coal to be unloaded at a higher capacity during cold, wet or icy weather than was previously possible. Other major features of the new coal unloading facility include a 95-ft tall concrete stacking tube that can accommodate a 38,000-ton coal pile, a belt magnet, two rail sidings, and two new coal crushers that were installed beneath existing reclaim openings in order to provide the ability to crush on reclaim in lieu of crushing before coal stack out. Construction Stage The construction phase of the project began in the spring of 2009 and was completed in October 2011. Coordination with local officials and residents continued during this phase of the project. The project employed experienced consultants to develop plans, perform studies, and ensure overall project compliance with environmental policies, permits and regulations. All construction contractors were required to submit a site specific Quality Assurance Plan. Contract requirements mandated that the contractor provide submittals for major materials and equipment used on the project. Major construction contractors sub- September 2013

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