In your research, seek USFS and BLM ground that is not under claim. Contact both state and federal agencies for a free list of available publications. Remember you are mostly interested in epithermal class precious mineral deposits associated with Tertiary acidic volcanics such as rhyolite and andesite. Also, epithermal silver and gold ores are often found as electrum, a gold alloy containing at least 20 percent silver. Seek old worked out drywash areas.
Small areas are best because they haven t been worked as much.
Also seek old, worked out, idle mines, preferably ones that had a history of free-milling gold values. Instead, detect the dump itself. Look for spills along old haulage roads, especially any sharp switch-backs. Most importantly, detect the dry slopes, arroyos, and gullies for at least a quarter-mile within the watershed below the mine. The country rock near epithermal veins is often altered even though the vein is fresh looking.