MARBLEHEAD-The Conservation Commission and the town want some questions answered on the clean up of the former Chadwick Lead Mills property on the Salem line.The commission?s third meeting to discuss the clean-up is scheduled for Thursday at 7 p.m. Meetings between the commission, the town and National Lead, the firm which has contracted to clean up the contaminated property, the site of a proposed 44-unit condominium development, began in September.NL Industries Inc. of Texas, the former owner of the property, has applied for commission approval of part of their cleanup plan, but they still need approval from the town.The cleanup is independent of the construction and will happen whether or not the construction is approved. Work is scheduled to begin in October 2008.Assistant Town Counsel Lisa Mead has told the commission that NL Industries is delaying the progress toward reaching an agreement for access and clean up and they have reneged on various time schedules.She also told the commission that there is no urgency and they should take all necessary time to insure proper review, and cautioned them to insure they have final plans before making any decisions.Dan Garson of Woodard & Curran, the firm that will perform the cleanup, has said the present NL application does not cover work on the coastal bank area because the town has requested a detailed plan on that work. Garson said the firm will file another application for the coastal bank area when the negotiations are finished.The commission has requested more information on the Wyman Woods parcel of the Chadwick property,Commission members have requested a new or amended notice of intent (application), describing work on the entire clean up, to insure the complete clean up of the entire site.