Among the latest high-grade surface drilling results, the company reported 1.9m at 0.1g/t gold and 660g/t silver, 1.3% lead and 0.58% zinc; and 0.2m at 0.31g/t gold, 3,210g/t silver, 7.9% lead and 13.5% zinc from San Patricio.

Underground sampling from the Sierra Plata part of the historic Veta Colorada mine included 331.2g/t silver, 1.4% lead and 0.96% zinc from muck on the 5.5 mine level.

Parral spans 3,432ha in Chihuahua and includes four historic mines, including La Palmilla which supplied silver to Mexico's federal mint in the late 1800s, Endeavour said.

"With the success of the 2018 surface drilling, underground sampling and metallurgical testing programs, management now views the Parral project as having good potential to become a profitable new mine," CEO Bradford Cooke said.

The statement follows Endeavour recently flagging an expected 5% shortfall to its 2018 production guidance and likely cost increase, citing delayed commercial production at El Compas, lower gold grades at Bolañitos and lower mine output at Guanaceví.

It is planning to complete an updated resource estimate for Parral, a preliminary economic assessment and start mine permitting, along with more definitive drilling, underground sampling and metallurgical testing in 2019.

The company had established resources for Parral earlier this year, including an indicated gold-silver 37,000 tonne resource grading 184g/t silver and 0.27g/t gold for 238,500oz silver-equivalent.

The inferred gold-silver resource comprised 2.28Mt at 262g/t silver and 0.25g/t gold for 20.57Moz AgEq.

Parral's Cometa silver-gold-lead-zinc resource has an indicated 8.78Moz AgEq and an inferred 5.4Moz AgEq.

Endeavour's Toronto shares rose about 10.6% or C27c yesterday to close at $2.82, capitalising it over $368 million.