WEST LEBANON — Twin State Sand and Gravel is again asking the city to extend its approval of a 92-acre mixed-use development slated for West Lebanon.

The company doesn’t have the $10 million required to build a system of roads, water and sewer lines to support its proposed Iron Horse Park, it said in a March letter to the Lebanon Planning Board.

And efforts to find a buyer for the development — which proposed 660,000 square feet of retail, office and industrial space in the area of Glen Road — haven’t proved fruitful, Manchester attorney Megan Carrier wrote.

The project, which was first approved in 2012, will move forward “once a developer has signed on,” she wrote. But until then, Twin State will require another two-year extension.

The proposal likely will be met with resistance when the Planning Board meets next week. Board members two years ago approved the project by a 6-2 margin, but also expressed concerns that plans to construct a 150,400-square-foot big-box store early on are no longer viable.

Others have suggested to no avail that developers try a different strategy altogether and refocus the project on industrial buildings.

Messages left for Bud Ames, co-owner of Twin State Sand and Gravel, were not returned.

The property was placed on the market in 2016 and remains listed for $15 million, according to real estate firm Cushman & Wakefield, which listed the development through its Manchester office.

However, leases for three industrial lots totaling 82,500 square feet within the development are now shown on the firm’s website as “off the market,” presumably because businesses have expressed interest in either buying or leasing them.

In her letter, Carrier said denying an extension would “render meaningless decades of work aimed at developing this property.” She said Twin State has invested at least $7 million in the project so far, with $600,000 of that spent in the last two years.

But even if the board approves an extension, it could be another 20 years before the development is complete.

A schedule submitted to city planners predicts construction on roads, sewer and water mains will begin this year, followed by the big box store in 2020. Ultimately, the developers hope to finish building industrial space in 2038.

The Planning Board is scheduled to discuss Twin State Sand and Gravel’s extension request at 6:30 p.m. on Monday, May 13, at City Hall.

Tim Camerato can be reached at tcamerato@vnews.com or 603-727-3223.