The deal also includes the buyer, MW Sorter LLC, taking on $11.8 million in liabilities.
Dateline and MW had been planning a joint venture at Gold Links prior to this deal.
The initial $2.27 million is to be paid in multiple payments over the next seven months or so, while $2 million of the $5.5 million in performance payments is due upon the first ounce of gold produced.
Colosseum operated in the late 1980s/early 1990s and is understood to have yielded about 344,000oz.
Dateline's previous drilling at the project "confirm(ed)" the presence of 812,000oz resource, 70% of which is measured and indicated.
Two previous holes completed by Dateline were about 100m below the historical resource shell, with one "over 100m (at) an average of 4.16 grams gold per tonne".
Colosseum covers about 1600 acres 8km north of Mountain Pass and includes "numerous outcrops that contain rare earth anomalies".
A rig currently drilling gold targets is set to move to the rare earth targets next.
Dateline's major shareholder is chairman Mark Johnson who holds around 15%, while managing director Stephen Baghdadi owns about 6%.
The company had cash of A$2.9 million at the end of March with another $1.2 million currently incoming as well as the payments for Gold Links.
Shares in Dateline were trading Monday at 2.4c, capitalising the company at $18 million.
