The explorer, in a statement, revealed that rock sampling saw high grades up to 23.4% copper, as well as 3.2 grams per tonne gold and 952 grams per tonne silver.
“These results from our maiden soil and rock sampling program at Copper Dome have exceeded our expectations,” said David Price, Rockfire chief executive.
“The coherent distribution of the copper-in-soil is encouraging for tonnage potential, whilst the copper grades in the soils are almost 80 times background levels."
Rockfire noted that just over a fifth of samples (23% of them) measured grades above 0.5 grams per tonne gold, 5 grams per tonne silver and 0.1% copper.
It noted that the samples define ridges radiating from the mapped centre of the porphyry system and said that there is also a potential for high-grade, vein-hosted mineralisation.
Rockfire also highlighted that copper was found in soils at a new, undrilled location to the north of the previous drilling. Sampling will now be extended to the south, to explore a second mapped porphyry.
Price added: "Our plan is to continue soil sampling towards the south to determine the extent of the copper-in-soil anomalism, which remains open towards the south and east.
“We will also expand our soil sampling towards the west, to explore the new western areas identified by rock sampling and geological mapping.
“This expansion of the original programme will occur after the field crews have completed ground magnetics at Double Event within the Lighthouse tenement."
In afternoon trading, Rockfire shares were 17% higher at 0.85p.
-- Adds share price --