The AIM-listed company owns a 24.44% stake in the project with Canada-listed Group Eleven the operator and majority holder.
Two step-out holes will be drilled to a total of 810 metres to test the extensions of the current resource of 5.1mln tonnes at 8.7% zinc and 2.6% lead.
The project, in Limerick, is adjacent to Glencore's Pallas Green zinc-lead deposit.
John Teeling, Arkle’s chairman and CEO, said "This is good news for shareholders. We are very well positioned in the emerging zinc province in the Limerick basin.
“These targeted holes are expected to grow the existing 5 million-plus tonne resource."
Shares rose 2.6% to 0.98p.