Tinka has identified some 55 million tonnes of indicated and inferred minerals resources to date at Ayawilca, hosted in a limestone formation, and the discovery of a second zinc-bearing limestone formation underneath the first has opened up the possibility to quickly and dramatically increase the resource size.

"We are seeing a repeat of the mineralisation at depth and have found strong evidence that the limestone repeats under the resource at a depth of 500 to 600m. If we find another high-grade pod it will make a big difference to the size of the project," Carman said.

Tinka plans to drill 10,000m in 2019, with six or seven holes testing the second limestone formation. These will drill through the existing resource and also act as additional in-fill holes.

The company expects to publish a PEA mid-year and results of metallurgical testwork. If drilling results are good the company may increase the drilling programme by 5,000m or 10,000m with a view to then update the mineral resource estimate and preliminary economic assessment.

"We are targeting a resource of 35Mt at a higher grade of 8% zinc equivalent," Carman said. "We have two types of ore and so we are looking at producing a zinc concentrate and a lead-silver concentrate."

Tinka has about C$12 million in cash and will spend $7 million on its 2019 work programme.

Carmen thinks once the PEA and metallurgical testwork are published the company may be attractive to a strategic investor. However, he cautioned that while zinc prices have been climbing recently as bonded warehouse inventories have fallen to multi-year lows, zinc companies are not getting a break on their share prices and continue to remain either flat or trending down.