The major's affiliate Rio Tinto Exploration Canada (RTEC) will use RAB drills to test copper showings, structural, geophysical, geochemical and boulder train targets generated by ongoing mapping and prospecting. RTEC says it is looking for higher-grade and thicker openpit stratiform horizons.

RTEC has also applied for a diamond drilling permit that it expects to receive by mid-July.

Meanwhile, an eight-person prospecting and mapping team has started systematic traversing at 2km intervals over the 52km-wide property. The team is also conducting geophysical and geochemical orientation surveys over mineralisation drilled last summer.

Forum CEO Rick Mazur said the exploration programme had the potential to uncover "the full extent" of copper and silver mineralisation at Janice Lake.

"We have barely scratched the surface on exploring this sedimentary basin which stretches for over 50km."

RTEC is earning an 80% interest in the 38,250-hectare Janice Lake property over four years, by spending C$30 million on exploration and making staged cash payments to Forum and project generator Transition Metals.

Noranda drill results from work in 1993 returned 0.77% copper over 33m, including 1.6% copper over 6m at 35m depth. Grab samples by Transition have returned values ranging from 0.34-9.35% copper and 0.7-61.7g/t silver, while 2018 drilling by Forum encountered 18.5m grading 0.94% copper and 6.7g/t silver, including 5.2m at 2.22% copper and 16.5g/t silver.

Shares in Forum (TSXV:FMC) have more than doubled over 12 months to a recent high of 11c, but have since fallen back to 8c, capitalising it at $9 million (US$6.7 million).