Tech investor and Southern Highlands local Peter Crown is believed to be behind the purchase of Hume Coal's Mereworth Aggregation in Berrima.
Title documents link two companies registered to Mr Crown to the property, which was offered to market in a rapid two-week campaign following the NSW Independent Planning Commission's rejection of Hume Coal's proposal for a mine on the site.
Hume Coal is a subsidiary of Korean steel-making company POSCO.
Listing agent Kim Watts of Ray White Rural declined to comment on the sale and no sale price has been disclosed.
Feedback during the sales campaign had pegged expectations at above $60 million.
The listing consisted of nine properties on a 1308 hectare land parcel, and included the historic Mereworth House.
The nine-bedroom property dates back to 1820 and was built to designs from acclaimed architect John Amory.
1970ML of water licences were also on offer as part of the sale, though it is unclear whether Mr Crown had also acquired those as part of the deal.
Mr Crown, who had not responded to requests for comment at the time of publishing, is the founder of private investment company Resilient Investments and owns property in nearby Burradoo.
His LinkedIn profile lists him as a director of property software platform Ailo and co-founder of social impact tech platform Ouno.