The details were spelled out in two building consents issued by council staff to Calder Stewart last month, and released to the ODT yesterday.
Details of the company's plans have not been disclosed, pending confirmation of the deal, and Calder Stewart staff have so far refused to comment.
Mayor Dave Cull said in February the company was expected to take "weeks or months" to confirm its decision to buy the property.
However, documents attached to the consents refer to a four-month timeframe to reach a decision, which would give Calder Stewart until next month to conclude the deal.
Mr Cull could not be contacted yesterday and Calder Stewart development director Alan Stewart did not respond to questions.
The consent documentation also showed the demolition work was expected to cost the company $350,000.
The company has released tender documents calling for expressions of interest from other companies interested in the work, as part of detailed due diligence work still under way, the ODT was told yesterday.
New Zealand Historic Places Trust Otago-Southland area manager Owen Graham last month said the trust was talking to the council about a covenant to protect the turnstile building, but not to spare other features of the old ground.
"That's what turns out to be a business decision between the council and the purchaser," he said.