Amazon is expanding its presence in Tucson with a major development under construction on the city’s west side.

The e-commerce giant is building an auxiliary distribution site for independent contractors and flex drivers to load up goods and gadgets for delivery.

Paperwork filed with the city of Tucson Planning and Development Services Department shows the project, dubbed Project Cactus, will receive and sort packages from larger warehouses to be transferred onto vans and smaller delivery vehicles.

The site is at the southwest corner of Silverlake Road and the Interstate 10 frontage road. Construction crews have already begun grading the land and placing infrastructure.

City records show the project received an initial building permit of $4.3 million.

A vehicle storage, washing and fueling station will also be at the site, as well as a customer pickup station for preordered merchandise.

The single-story warehouse and adjacent vehicle support stations will sit on about 12 acres and will operate 24 hours a day.