It is understood the land purchase completes a recent redevelopment phase for the foundry, including the installation of upgraded equipment and building modifications, possibly worth several million dollars.
However, Esco is in the process of registering for an initial public offering and is in a regulatory "quiet period" banning news announcements. The company declined to comment.
The Dunedin property is one of two formerly leased sites which have been sold to their respective Chinese and American owners in Otago and Canterbury for about $1 million apiece, after decisions were released by the Overseas Investment Office (OIO).
In Canterbury, Chinese-owned Synlait milk was similarly granted consent by the OIO to buy the freehold site of its milk processing facility for $1.1 million.
Consent for the Dunedin purchase was granted in late December for the 0.84ha property which had been leased from Farra Engineering since 2007, Farra having sold the foundry to Brisbane-based AustCast which then sold it to Esco in December 2010.
Esco, which employs about 4700 people globally, is a worldwide supplier of parts to the mining and construction industry, including crushers, blocks, tooth systems, dragline buckets and truck bodies, and in late December 2010 bought the shares of privately owned AustCast in Brisbane, which included the Dunedin subsidiary Newlcast.
In July 2010, Esco bought Swift Group in Brisbane, including several manufacturing facilities.
Synlait, which is majority-owned by Bright Dairy, of China, has leased the 48.5ha of land at Dunsandel from Synlait Farms Ltd.
Obtaining long-term control of the land would give Synlait a solid base and secure position on which to continue building its business to a level that would be of substantial benefit to Canterbury and New Zealand, the December decision summary said.
The company, which started processing milk in 2008, added a $100 million infant nutritional formula facility to its site last year, targeting the growing Chinese market.