Golden Minerals Co.'s inferred resource at its Santa Maria silver-gold project in Mexico declined 25% to 120,000 tonnes due to an adjustment in the location of the claim.
The project now holds indicated resources of 180,000 tonnes at 404 g/t of silver equivalent for 2.31 million ounces and inferred resources of 120,000 tonnes at 411 g/t of silver equivalent for 1.64 million ounces.
According to a March 31 release, the resource adjustment will reduce the net present value of the project by less than 3%, to US$6.3 million.
In February, a preliminary economic assessment for the Santa Maria project defined an after-tax net present value of US$6.4 million, at an 8% discount rate, with an internal rate of return of 84%.
Meanwhile, Hecla Mining Co. unit Minera Hecla SA de CV exercised its right to extend the lease of Golden Minerals' oxide mill in Durango, Mexico, for an additional 18 months, to Dec. 31, 2018.
Golden Minerals received about US$4.4 million in net cash flow from the lease in 2016 and expects net cash of about US$4.8 million in 2017.