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Markland Dam lock undergoes inspection and salvage work

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By Dave Taylor

Inspections are underway this week to determine if one of the miter leaf gates was damaged when the downstream lock gate on the 1,200-by-110 foot chamber failed during operation Sunday, Sept. 27.

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The second of the two leaves is resting on the bottom of the lock chamber. The other inoperable lock leaf remained affixed to the lock chamber and required stabilization after what was termed a “catastrophic failure,” by officials from the U.S. Army Corps of Engineers Louisville District.

On Monday, the Henry M. Shreve floating crane, of the Corps’ Louisville Station Repair fleet, lifted the damaged middle wall miter gate leaf out of the lower end of the main lock chamber and placed it on a DeLong barge for inspection. If salvageable, a repair will be undertaken.

“The Shreve is an integral component of miter gate repairs and travels all over the region, as far away as St. Louis in maintenance operations,” said Carol Labashosky, media spokeswoman for the Corps’ Louisville District.

The Shreve displaces 5,400 tons. The barge-mounted crane has a 200-foot boom with a lifting capacity of 550 tons, Labashosky said. A typical miter gate leaf weighs 250-300 tons.

On Monday, the repair crew used the Shreve, to attach a lifting beam to two

lifting eyelets at the top of the gate leaf while it hung secured in the lock chamber. Once connected, the Shreve lifted the gate leaf, swinging it about 120 degrees, and suspended it above the waiting DeLong barge. While the leaf was suspended, the repair crew attached rockers to the leaf. The gate was then placed on the DeLong barge and laid in a prone position.

    The process was lengthy and weather dependent. Wind speeds had to be less than eight miles per hour.

    “This is just right,” Laboshosky said of Monday’s weather conditions as a Louisville television crew circled overhead in a helicopter.

    With the gate placed on the Delong barge, the repair crew will be able to assess the structural integrity and determine if the it is salvageable. Once that determination is complete, engineers will then develop and implement a repair plan.

    A contract for $352,000 has been awarded to Ohio River Salvage, Inc., Crescent, Pa., to provide equipment and services to pull and salvage the submerged miter gate leaf of the bottom of the bulkhead sill, Laboshosky said.

That gate leaf became separated from the lock wall and sank during the Sept. 27 incident, coming to rest in the lock chamber. Water from the lock cannot be emptied until the gate leaf is pulled away from the bulkhead sill. This work is part of the preliminary repair plan that is ongoing, Laboshosky said.

A salvage crew will be working to move the submerged gate leaf off the lock chamber sill. Then bulkheads can be installed and the chamber can be dewatered.

Since the lock failure tows and barges have been using Markland’s smaller auxiliary lock, which is 600 feet long and 110 feet wide. The locks are used to raise and lower chamber water levels to enable boats to navigate between the upper pool water level of 455 feet, and the 420-ft lower pool level. As a safety precaution the auxiliary lock was closed to river navigation during Monday’s salvage operation.

The Corps received funding earlier this year for new miter gates for Markland. Oregon Iron Works in Eugene, Ore., was awarded the contract to place new miter gates. The miter gates were scheduled for delivery in late 2010 with installation in 2011.

The Markland Lock miter gates will be delivered ready for use nine months ahead of schedule, Laboshosky said. The delivery date for the 1,200-foot lock chamber was originally June 2010 but was subsequently delayed until December 2010. The Louisville District has arranged for the contractor to deliver the downstream gates by March of 2010.