Esco Corp., a maker of mining and construction parts, plans to demolish its large Northwest Portland main plant.

That would open much of the 15-acre site for redevelopment. It sits on the edge of an industrial sanctuary but borders a booming section of Northwest Portland. City zoning, however, restricts its future use.

The company shuttered the foundry, parts of which are a century old, last year amid a protracted downturn in product orders. The company said it would move the work to Esco factories in Newton, Mississippi, and Taiyuan, China, as well as a sourcing partner in Italy.

Shannon Huggins, an Esco spokeswoman, said the company hasn't determined its plan for the site, but that it had always intended to "decommission" the plant. The company has previously discussed research and development functions on the site, but it's also considering a sale.

"Our leadership team is looking at options, but everything is still on the table," Huggins said.

The company plans to keep intact its world headquarters at 2141 N.W. 25th Ave., as well as a research site across the street. It has other scattered holdings in Northwest Portland.

One part of the site, a 1940 factory building, is listed on the city's Historic Resource Inventory. Esco has asked to have it removed to clear the way for the demolition.

The plant sits blocks away from a section of Northwest Portland that's seen hundreds of new apartments and retail stores, including on former industrial sites.

The Esco site is currently zoned for heavy industry. But Esco successfully pushed for the city's comprehensive plan to designate the land for "mixed employment," which would allow the company or a future owner of the land to seek a change to that more flexible zoning.

That zoning would allow a broader range of uses, including for businesses that more resemble offices than industry. It follows the model of Portland's Central Eastside, where software and creative marketing firms work alongside the industrial firms that have long called that district home.

But the zone would not allow for residential uses, and it would restrict retail uses.

That company couldn't seek the zoning change until the city's comprehensive plan takes effect in January.

-- Elliot Njus

enjus@oregonian.com

503-294-5034

@enjus