The offering consisted of 700,000 common shares at 50 cents each.
The miner said the new funds will be used for general working capital.
In October, Vancouver-based Rathdowney said it optioned out 31 of its prospecting licenses in the Irish Midlands zinc-lead district to Teck Resources' Irish subsidiary.
The licenses comprise the Westmeath South, Westmeath North, Galway, Laois, Longford and Meath properties in Ireland.
"Rathdowney's work on these prospecting licenses in Ireland has provided a solid platform for Teck Ireland to advance exploration and include in its regional geophysical surveys, targeting major concealed zinc-lead mineralizing systems," said Rathdowney's CEO and president, John Barry, in a statement at the time.
The Teck subsidiary has the option to acquire a 100 per cent interest in the prospecting licenses by spending C$4.39 million on or before December 31, 2016.
Rathdowney will retain a 2 per cent net smelter returns royalty on minerals extracted from the areas covered by the licenses.
Rathdowney retained a significant participation in any major economic discovery, while also being able to focus its current resources on the Project Olza zinc-lead project in Poland.
The private placement was part of the option deal, and took place once approval from the deal was received from the Ministry in Ireland.
The junior zinc and lead explorer is focused on its Olza project in Poland, located in the prolific Upper Silesian Mineral District, an area of extensive Mississippi Valley-type deposits in which zinc-lead mining has taken place since the 12th century.
In September, Rathdowney was granted a third exploration concession, expanding its Olza zinc-lead property to now cover some 150 square kilometres. The third concession, called Chechlo, covers 50.8 square kilometres and is next to the company's Rokitno concession.