Diablo Resources (ASX: DBO) is advancing exploration across its United States portfolio, with the company highlighting the potential of its Horn Silver Project in Utah after first-pass sampling returned high-grade results.

The initial sampling program delivered high-grade silver, gold and copper results, providing an early indication of the mineralisation present across the project and strengthening the company's interest in the broader Horn Silver system. The project takes its name from Utah's historic Horn Silver mine, located in the Frisco mining district in the state's west, which was one of the major silver producers in the United States during the late 19th century before closing after a mine collapse in 1885. The district has seen comparatively little modern systematic exploration, a factor that often draws junior explorers to historic mining camps where historical workings can guide, but not substitute for, contemporary drilling.

According to the company, the latest results represent an early stage of exploration at Horn Silver. Surface sampling is generally treated as a preliminary tool in exploration, and companies in this position typically look to confirm whether grades observed at or near old workings persist at depth through drilling. Diablo now intends to build on the initial sampling work by extending it across the broader project area.

The progression of the patented claims option is also described as an important step for the project. Broader access could potentially allow Diablo's exploration team to work across a more consolidated area. Securing patented claims in the US can also simplify permitting relative to unpatented claims on federal land, since patented ground is privately held.

Beyond Horn Silver, Diablo is preparing to commence drilling at its North Star Project, which the company says provides another near-term exploration catalyst. Drill programs at early-stage projects are typically the first opportunity for investors to test whether surface results are indicative of mineralisation at depth.

With activity planned across both Horn Silver and North Star, Diablo is entering a period of increased exploration activity as it works to advance its US assets. The company is one of a number of junior explorers pursuing precious and base metal targets in the western United States, a jurisdiction that has attracted renewed exploration interest in recent years.

Managing director Lyle Thorne discussed the Horn Silver results, the path towards drilling and the outlook for the company's US exploration portfolio in a HotCopper interview accompanying the original article at The Market Online.