* Minera to receive 0.4 US Gold shares for each share
* McEwen is chairman, chief shareholder and CEO of both (Adds details, recasts)
TORONTO, June 14 (Reuters) - The largest shareholder and chief executive of US Gold UXG.TO has proposed a takeover of Minera Andes Inc MAI.TO, another company he runs, to form a mid-tier silver miner with operations in the Americas.
Under the terms of the all-stock proposal by Rob McEwen, the goldbug founder of No. 2 gold miner Goldcorp (G.TO), Minera Andes shareholders would receive 0.4 of a US Gold common share for each Minera share currently held.
At that conversion rate, Minera's 282.7 million shares outstanding would be worth some 113.08 million US Gold shares, which closed on Monday at C$5.38, giving the deal a total value of C$608.37 million ($626.25 million).
"The merger of US Gold and Minera Andes would be transformative, creating a dynamic, new precious metal company," said Rob McEwen, who is chief executive of both companies and whose investment in the combined company would amount to about C$345 million.
Rob McEwen was the founder and former chairman of Goldcorp, the world's second-largest gold miner by market capitalization. He also heads other junior mining companies.
US Gold explores for gold and silver in the Americas and is advancing its El Gallo project in Mexico and its Gold Bar project in Nevada toward production.
Minera Andes is an exploration company looking for gold, silver and copper in Argentina, where it has stakes in three assets, including a 49 percent interest in Minera Santa Cruz, owner of the San Jose Mine near the Cerro Negro project owned by Goldcorp.
It is also 100 percent-owner of the Los Azules copper deposit as well as a portfolio of exploration properties in Santa Cruz province.
($1=$0.97 Canadian) (Reporting by Pav Jordan; editing by Rob Wilson)