** Shares of Sun Silver SS1.AX gain as much as 6.3% to A$0.850, their highest level since June 10
** The silver and gold explorer says it has received the regulatory approval needed for drilling across the Maverick Springs silver-gold project in Nevada, U.S.
** Co says approval allowed co to drill across key targets of the project
** Stock up 32% this year, including the day's move
(Reporting by Rajasik Mukherjee in Bengaluru)
((Rajasik.Mukherjee@thomsonreuters.com))