Cleo is 1.5km away from the main deposit, with RC intercepts including 5m grading 3.8 grams per tonne gold and 5m at 4.2gpt.
"Mineralisation in fresh rock is hosted by fine grained micro-diorite to amphibolite, as compared to granodiorite gneiss at the Rebecca, Duchess and Duke deposits, and this potentially opens new exploration fronts to the south, and in other under-explored parts of the project," Apollo said.
"Mineralisation is also notably present in the shallow oxidised profile, which is unusual for the project area."
Meanwhile, drilling is continuing at the mainstay 775,000 ounce Rebecca deposit.
Apollo started the quarter with A$19.8 million cash.
Shares in Apollo were unchanged at 34.5c in early trade, capitalising the company at $93 million.