Gold explorer Proto Resources and Investments Ltd has launched a $3.5 million initial public offer (IPO).

The company whose assets include historic gold workings north of Broken Hill, is offering 17.5 million shares at 20 cents each.

The IPO has a minimum subscription of $2.5 million.

Proto expects to have 35.49 million shares on issue at the time of listing, giving it a market capitalisation of $7.1 million.

Proto's assets include the Tibooburra gold project north of Broken Hill, the Arunta lead-zinc project in the Northern Territory, and the prospective Mt Vetters gold and nickel project in Western Australia.

Proto Resources chairman Andrew Mortimer said the Tibooburra project had high-grade gold on the surface, running from three to 70 grams per tonne.

In the pre-1890 gold rushes, the area yielded 75,000 ounces of gold.

The IPO opens on October 9 and closes on November 3, with listing on the Australian Stock Exchange expected around November 17.