Southerngurl asked where to file a mining claim. Any BLM land that is not national forest, national park, wildlife preserve, military base, or otherwise reserved for some special purpose. Most BLM land can be claimed for minerals.
I live in Nevada and most any place in the state can be claimed. Same is true for Arizona, New Mexico , Utah, etc.
I just checked and the rules have changes somewhat. In addition to the county recording fee (usually about $10) a $100 annual fee must be paid to the BLM. The BLM fee was enacted to stop cheaters, who used to simply swear-out a statement that $100 work had been done when it hadn't.
To see where mineral claims have been filed in your county you could check with your county recorder's office. They can give you an idea where claimable land might be found in your area.