Much harder for Fire Depts to get Burning permits today. Most FDs are looking for houses. Not too much into buildings especially condemned ones. Generally only the County owned landfills, accept Burned material. They usually charge more than Private landfills, & don't permit Private LF to accept burn material, roofing, or construction material.
Most Every Vintage Mill taken down now days, are "recycled" as much as possible. Old Brick, just like Old Lumber is valuable. Then the steel is scraped, & the left over brick & concrete is ground or hauled to a recycling seller. Biggest amount to be Dumped, is the roofing material. I don't have names, but Companies Pay to recycle these Mills.