The March drilling hit 32m at 4.9 grams per tonne gold from 93m, including 1m at 20.2gpt and 1m at 40.3gpt.
It represents the best diamond drilling assay to date, with coarse gold also evident in the core.
Another hole hit 23m at 1.73gpt gold from 83m, including 2m at 5gpt and 3m at 5.9gpt.
The true width of the intersections is estimated at about 10m.
Earlier this month, First Au reported a maiden inferred resource for Gimlet of 642,359 tonnes at 3.33gpt gold for 68,731 ounces of gold, using a 1.3gpt cut-off.
The resource was announced after only two reverse circulation drilling programs.
A 5000m aircore program will begin next week along strike of Gimlet, with first results anticipated in July.
First Au completed a backdoor listing in June last year, and discovered Gimlet in late 2018.
Gimlet is just 15km outside Kalgoorlie and is within trucking distance of the Mungari, Lakewood, KCGM, Kanowna Belle and Paddington mills.
The project neighbours Intermin Resources' 289,000oz Teal project.
The company raised A$5.3 million when it listed last year and had $2.5 million cash at the end of March.
Shares in First Au jumped 11.8% to 1.9c, but rose as high as 2.1c intraday.