Shares in Sunrise Resources PLC (AIM:SRES) rose 28% to 0.018p after the AIM-quoted explorer reported further high-grade zinc, lead and silver results from surface sampling in Nevada.
Narrow vein samples at the Ridge Top prospect, part of the Reese Ridge project, graded up to 9.9% zinc, more than 20% lead and 192 grammes of silver per tonne.
More significant for the project's economics, mineralisation was confirmed in the rock on either side of those veins.
A 0.6 metre chip sample from the hanging wall returned 4.8% zinc, while a footwall sample graded 5.8% zinc, 1% lead and 17 grammes of silver.
Hanging wall and footwall refer to the rock above and below a mineralised structure, and grades at those widths matter because narrow veins alone rarely support a mine.
The full width of the footwall zone has yet to be exposed.
Sunrise is building a three-dimensional geological model combining the new mapping with historical airborne geophysical data to select drill targets.
That geophysics identified a zone of low resistivity, which can indicate the presence of sulphide minerals, extending from near surface to almost 1,000 metres depth.
All the high-grade mineralisation found so far sits directly above it.
Patrick Cheetham, executive chairman, said the company wanted to drill both the down-dip continuation of the surface results and the deeper anomaly, which it believes could represent a large sulphide system.
Sunrise argues the project fits the carbonate replacement deposit model, in which metal-bearing fluids replace limestone near an igneous intrusion.
Cheetham pointed to South32's Taylor deposit in Arizona, which holds 138 million tonnes at a zinc-equivalent grade of 8.61%, and to i-80 Gold's Ruby Hill discoveries in Nevada as examples of the scale such systems can reach.
Earlier sampling at Reese Ridge returned assays of up to 29.6% zinc, alongside gallium values of up to 69 parts per million.
Gallium is classified as a critical mineral because of its use in semiconductors and solar technology.
The next phase, comprising further ground geophysics and drilling, is subject to funding.
The results follow a strategy update on 14 July that refocused the company on base and precious metals.
One inconsistency worth querying: the highlights describe the footwall chip sample as 3.3 metres, while the detailed section and sample LR-056 give it as 3 metres.