Gold Panner's Manual by Garnet Basque
Back of the book blurb: "Test your Midas Touch!
Here's your guide to every aspect of gold panning and prospecting. Pick up a piece or two of surprisingly simple equipment and size up that stream by your campsite—these days, even a few grams of gold are worth hundreds of dollars.
The techniques, the pans, the pickaxes and the educated guessing required to pan gold haven't changed much since the Klondike gold rush. In a few chapters, you'll have the information you need to strike out and maybe even strike it rich.