Black Bear Minerals (ASX: BKB) is ramping up on-site activities in the lead-up to the start of underground drilling at the Shafter silver project in Texas, USA.

According to the company, work at the site is progressing, with drill planning underway and the initial holes expected to focus on areas around previously operated stopes that are difficult to test efficiently from surface.

Shafter, located in the Chinati Mountains of Presidio County in West Texas, is a past-producing silver operation. Silver was mined at the site from the early 1880s, with historically reported production of roughly 30 million ounces before the original Presidio mine closed in 1942. The project was most recently operated in 2012–13, when then-owner Aurcana Corporation poured silver before suspending operations at the end of 2013 amid a falling silver price.

"We're completing the final operational-readiness steps to access the underground developments at Shafter and commence underground drilling, leveraging existing decline development and ground support that remain in good condition," CEO Dennis Lindgren said.

"Drill planning is underway, targeting extensions to high-grade silver mineralisation while supporting planned JORC conversion, MRE updates and key mine-restart inputs. Leveraging the underground workings allows us to rapidly advance exploration while supporting our restart ambitions."

Mr Lindgren said Black Bear has been progressively returning the Shafter site and its underground infrastructure to an operational-ready state. The restart work coincides with record global industrial demand for silver in recent years, driven largely by photovoltaic and electronics applications, according to the Silver Institute's World Silver Survey.

Planning for the initial underground drilling program will concentrate on areas accessible from the existing underground development, including the Presidio East and Ramp areas. The program will be designed to support further definition of the mineralised system and to test for extensions to silver mineralisation both within and beyond the footprint of the existing foreign mineral resource estimate (MRE). Under the JORC Code, which governs resource reporting for ASX-listed miners, Shafter's estimate is classified as a foreign estimate because it was originally reported under Canada's NI 43-101 standard, and the planned conversion would see it re-reported as a JORC-compliant mineral resource.

The underground campaign will also aim to provide additional drilling coverage in and around the Presidio mine workings. The company has previously reported that mineralisation remaining within the mine area, which is currently excluded from the foreign MRE, encompasses approximately 1km of strike that is yet to be adequately quantified.

In addition, underground drilling is intended to complement further planned surface exploration drilling across the broader Shafter project, and will provide additional geological information to support resource definition, the planned JORC conversion and future MRE updates.

Priority work is expected to include resource validation and infill drilling in areas relevant to potential early mine sequencing, improved geological and geotechnical definition around existing developments, and verification of conditions in areas that may be incorporated into future mine planning.

In trading, shares in BKB were up 0.76% at 66.0¢, with a market capitalisation of $99.84 million.