The stand-out intersection reported was 363.1m at 1.02g/t gold, 0.51% copper and 1.72g/t silver, or 1.81g/t AuEq, within a broader 904.12m at 0.98g/t AuEq from 15m.
"Porphyry discoveries of this scale and tenor are uncommon," exploration vice-president Charles Greig said.
GT Gold said seven widely-spaced holes had targeted the porphyry this year, and all had achieved strong visual intercepts of the target mineralised monzodiorite over "considerable intervals".
The company raised more than C$6.4 million earlier this month and said it was fully funded into 2019 for the expansion drilling programme underway.
Greig said GT saw tremendous upside for expansion at Saddle North.
GT Gold's shares shot up more than 46% yesterday to C$1.14, valuing it close to $114 million.
They have spent much of this year around the 70c mark but had traded above $2 just over 12 months ago, as the company reported multiple high-grade intercepts at its Saddle South gold discovery.