The Vancouver-based company says its 2012 drilling program found a previously undiscovered area, which it calls the Legacy zone, close to the mine's central pit.
Novagold says it plans to continue drilling this year to get more information about the size of the Legacy zone, which is at least 700 metres long.
Galore Creek has the potential to become Canada's largest and lowest-cost copper mine, according to the company.
Novagold is developing Galore Creek through a 50-50 partnership with Teck Resources Inc. (TSX:TCK.B), one of Canada's largest mining companies.
Teck shares traded at $32.02, up 26 cents, on the Toronto Stock Exchange as part of a general rally in Canadian resource stocks. Novagold shares gained five cents to $4.12.