MARBLEHEAD – Workmen are nearly a month into the clean-up and rehab of the landfill-contaminated condo property at 52 Stony Brook Road and Director of Public Health Wayne Attridge said they are on schedule to complete the project in mid-to-late December.Charter Environmental Inc. of Quincy was hired to do the work on a low bid of just under $644,000. They started Nov. 4.?They?re right on schedule,” Attridge said. “They?re doing a good job, very clean, very organized and they?re trying to keep the neighbors happy.”Selectmen voted Aug. 24 to take an eight-month easement on the property, but residents plan to return to the partially contaminated four-unit building at 52 Stony Brook Road as soon as the work is complete, so the town scheduled that clean-up first.Once that work is done the clean-up will continue on the contaminated areas at 55, 56 and 57 Stony Brook Road, which the town has purchased.Contaminated material is scheduled to be removed from the site and deposited in the town?s landfill, which will be capped after a new transfer station is built.