The investigation and report by consulting firm, RSC Mining & Mineral Exploration, shows maiden gold resource reports made up 42% (37 of the 88) of all initial resources reported in 2017.

While five more maiden gold resource reports were filed in 2017 compared with the previous year, there was a plus-20 million-ounce jump in the inferred, indicated and measured resources reported. A major part of the increase came from Polymetal International's Nezhda project in Russia.

The 88 maiden mineral resources for 35 different commodities reported by public companies in 2017 compared with 81 in 2016.

After gold, silver, copper and lithium accounted for the bulk of the maiden resources, though zinc (10) and lead (8) resource reports surged, and there was a fourfold rise in coal resource reports.

Geographically, Australia accounted for 20 maiden resources in 2017 (mirroring 2016) and the USA had 14 maiden resources reported.

RSC analysed 3,237 exploration drilling updates released during 2017, up 51% on the number released in 2016. The consulting firm said there were no big surprises in the locations of exploration drilling: "Australia was the most popular location, closely followed by Canada. The USA and Mexico also released a large amount of exploration drilling reports," it said.