Among the highlights, Arizona hit 48.77m assaying 7.3% combined zinc-lead, 170.1g/t silver and 1.6% copper.

The company said the step-out drilling showed the potential for resource growth at the zinc-lead-silver deposit in Arizona's Santa Cruz county, plus robust copper grades in the new zone and another previously identified zone to the east.

Meanwhile Arizona has started work on its twin exploration declines at Taylor ahead of schedule after gaining approval in March.

It is aiming to deliver a feasibility study mid-year and is targeting first mineralised material to plant in 2020.

Australian-based South32 (ASX: S32) holds 17% of Arizona and said earlier this month it was "committed to working with the company to unlock the full potential of the Hermosa project".

Arizona said Taylor would be one of the world's top five zinc-equivalent producers when it released its updated preliminary economic assessment in January.

The company had cash and equivalents just over US$41 million at the end of the March quarter.

Its share price has almost doubled in 12 months and closed down C7c yesterday to $4.08, capitalising it around $1.28 billion.