Total resources are now 7.79 million tonnes grading 6.8% zinc, 1.8% lead and 32 grams per tonne silver for 530,000t zinc, 140,000t lead and 8.04 million ounces silver using a 1% zinc cut-off.

 

Around 60% of the contained zinc sits within the indicated category. 

 

The new resource estimate comes after 15 months of drilling for 6231m, and 34 channel samples, adding 4.5Mt of zinc ore, which benefited from Alta's improved knowledge of the geology leading to more effective target selection and efficient drilling from the existing workings, particularly into the Bracca and Ponente areas.

 

Alta says around 741t were added for every metre drilled, a fourfold improvement compared to the work that informed the 2017 resource estimate.

 

Managing director Geraint Harris said the aim now was to fast-track the development of Gorno into one of Europe's premier zinc-lead-silver deposits.

 

The initial steps are mining and metallurgical studies. Early tests suggested the lead and zinc can be separated with high metal recoveries into clean, high-grade sulphide concentrates.

 

Drilling continues at the mine, targeting areas outside the resource envelope, given the deposit remains open in all directions.

 

Harris said an exploration target, which would elucidate the market on the remaining large-scale potential, was being prepared.

 

Gorno has over 230km of workings that were developed prior to its closure in 1980. 

 

A prefeasibility study completed on the 3.3Mt Zorzone area determined that the mineralisation can be mined using a modern trackless underground fleet.

 

Alta shares closed at A8c on the ASX on Tuesday, valuing the company at $23 million.

 

The stock has traded between 6-13c over the past year.