Workers pour concrete to form the base of a 10-foot oil derrick replica in the middle of Grand Lake, south of Kozy Marina. A barge hauled a cement truck bearing 20 yards of concrete to the site to hold the rip-rap placed there earlier this year. Once the concrete is set, a pad will be erected to hold the derrick, which is expected to arrive in two pieces. It will be removed during the winter months. Brad Fisher, a member of the Grand Lake Recreation Club that spearheaded the venture, said the project cost is about $5,000 and was raised through club and private donations. The replica will sport a sponsors' plaque and a navigational aid light so boaters can see it at night, Fisher said. Grand Lake in 1891 was home to the world's first offshore oil well. Hundreds of oil and natural gas-producing structures were once visible along the shoreline.